An Educational Blog
Closed-Circuit Television (CCTV):
CCTV pictures showing Al Qaeda’s terrorists Mohamed Atta and Abdulaziz Alomari boarding a 6:00 a.m. flight from Portland to Boston’s Logan International Airport on September 11, 2001.
CCTV footages of 2015:
In the past people didn’t misbehave because they thought God was watching them. Today we’ve replaced an all-seeing God with the glassy eye of the CCTV camera. A CCTV camera can operate 24 hours a day, seven days a week, and 365 days a year without a toilet break or lunch. It does not need a holiday, maternity leave and rarely goes sick. There were 25 million CCTV cameras in operation worldwide, with 2.5 million in the UK in 2002 but today the figure is doubled. Practically every major city now boasts a CCTV system aimed at, among other things, preventing, detecting and reducing crime. Increasingly these developments are mirrored in villages, shopping malls, residential estates, transport systems, schools and hospitals. In short, for many citizens it is now impossible to avoid being monitored and recorded as we move through public space. One of the most high-profile cases where CCTV has helped solve crime is the 7/7 London bombings. Police examined an estimate of around 2,500 items of CCTV footage in order to identify the four suicide bombers. The four suspects were isolated on railway station footage within four days of the attacks. A common argument in favor of CCTV is: ‘If you are doing nothing wrong, you have nothing to worry about.’ However, this does not answer the question: ‘If you are doing nothing wrong, why are you being watched at all?’ Is crime control the principal motivation behind increased surveillance or are the reasons more complex? Does surveillance violate peoples’ right of privacy? What are its implications for social control? Does surveillance actually reduce crime? I attempt to answer these questions. Humans are utilizing three technologies in 21’st century, computer-internet, cell phone and CCTV; and they are all inter-connected. I have already discussed cell phone and computer-internet in my earlier articles and today I complete the circle by discussing CCTV.
Abbreviations and synonyms:
VCR = video cassette recorder
DVR = digital video recorder
SD cards = secure digital cards
IP = internet protocol
CCD = charged couple device
CMOS = complementary metal oxide semiconductor
ADC = analog-to- digital converter
DAC = digital-to-analog converter
IR = infrared
DSP = digital signal processing
HD = high-definition
SDI = Serial Digital Interface
TVL = television lines
SD CCTV = standard definition CCTV
IPTV = internet protocol TV = watching TV on internet
FPS = frames per second
LED = light emitting diode
PTZ = pan-tilt-zoom
NTSC = National Television System Committee
PAL = Phase Alternate Line
SECAM = Sequential Color and Memory
VHS = video home system
LCD = liquid-crystal display
CRT = cathode ray tube
DVD = digital video disc = digital versatile disc
CD = compact disc
NVR = network video recorder
VGA = video graphics array
JPEG = Joint Photographic Experts Group
MPEG = Motion Picture Experts Group
ASB = anti-social behavior
VA = video analytics = video content analysis = VCA
ANPR = Automatic Number Plate Recognition
VMD = Video Motion Detection
CCTV is an acronym of many things:
People must know that Chinese Central Television is also abbreviated as CCTV which is a predominant state television broadcaster in mainland China. There is another meaning of CCTV i.e. Closed circuit televisions used by individuals who have low vision. Here a CCTV is a video magnifying system that uses a stand-mounted or handheld video camera to project a magnified image onto a video monitor, television screen or computer monitor. Potential uses for such a portable CCTV include reading your mail, newspapers, magazines, bills, books, prescription bottles, writing cheques, filling out crosswords puzzles, viewing pictures, etc. Although cable television is technically a form of CCTV, the term is generally used to designate TV systems with more specialized applications than broadcast or cable television. Other common forms of CCTV include live on-site video displays for special events (e.g. conventions, arena sports, rock concerts); pay-per-view telecasts of sporting events such as championship boxing matches, and “in-house” television channels in hospitals, airports, racetracks, schools, malls, grocery stores, and municipal buildings. CCTV has many industrial and scientific applications, including electron microscopy, medical imaging and robotics, but the term “closed circuit TV” refers most often to security and surveillance camera systems. In this article, Closed-circuit television (CCTV) means cameras doing video surveillance. Video surveillance is defined as surveillance by a closed circuit television system for direct visual monitoring and/or recording of activities of a person or place. Surveillance is the monitoring of the behavior, activities, or other changing information, usually of people for the purpose of influencing, managing, directing, or protecting them. Surveillance is very useful to governments and law enforcement to maintain social control, recognize and monitor threats, and prevent/investigate criminal activity.
Introduction to CCTV:
Closed-circuit television (CCTV) surveillance has become ubiquitous in everyday life. Their employment is commonplace in a variety of areas to which members of the public have access. While walking down Republic Street, visiting a shop or bank or sipping a cup of coffee, we are caught on camera. One feels compelled to recall one of George Orwell’s most famous novels of the twentieth century, titled ‘Nineteen Eighty-Four’, where Orwell sets in an imaginary totalitarian future with each person being subjected to round the clock surveillance. He makes use of bold phrases, the most notorious of which being, ‘Big Brother is watching you’.
Closed Circuit Television (CCTV) is a television transmission system in which live or prerecorded signals are sent over a closed loop to a finite and predetermined group of receivers, either via coaxial cable or as scrambled radio waves that are unscrambled at the point of reception. CCTV systems are based on strategically-placed video cameras, which capture footage and then broadcast it to either a private (closed) network of monitors for real-time viewing, or to a video recorder (either analog or digital) for later reference. The most recent development is web camera server which uses the Internet for remote surveillance.
CCTV also known as video surveillance is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors. It differs from broadcast television in that the signal is not openly transmitted, though it may employ point to point (P2P), point to multipoint, or mesh wireless links. Though almost all video cameras fit this definition, the term is most often applied to those used for surveillance in areas that may need monitoring such as banks, casinos, airports, military installations, and convenience stores. The use of video in distance education is included in CCTV ambit. An obvious use for CCTV is to prevent crime and malpractice but it is also a valuable business management tool offering staff protection, supporting Health & Safety initiatives, aiding investigations, proving innocence and avoiding lawsuits; other examples of its use are help with production control and other observational objectives in factories where, for example, conditions are unsuitable for human intervention. It can be used a wide range of other applications, such as traffic surveys, keeping an eye on livestock and for monitoring wildlife activity, to name but few. The use of CCTV in the home environment is becoming more popular. Not only does it improve general security, it can help to defend against anti social behaviour, and is a way of keeping an eye on children and pets.
Changes in CCTV technology have been driven by three main requirements:
1. The first is the need to reduce the cost of recording and storing video for long periods.
2. The second is the need to reduce the amount of space required by these systems.
3. And the third is the need for improved accessibility.
Camcorder vs. CCTV camera:
A camcorder is an electronic device combining a video camera and a video recorder, typically used for consumer video recording. The earliest camcorders were videotape-based, recording analog signals onto videotape cassettes. In the 21st century digital recording became the norm, with tape replaced by storage media such as internal flash memory and SD cards. Analog CCTV cameras are not camcorder as they need VCR or DVR for video recording and storage. IP CCTV camera may be called camcorder because they can record and store video images on SD cards. Secure Digital (SD) is a nonvolatile memory card used extensively in portable devices, such as mobile phones, digital cameras, GPS navigation devices, handheld consoles, and tablet computers. It is a family of solid-state storage media.
Webcam vs. IP (internet protocol) camera:
Unlike an IP camera (which connects using Ethernet or Wi-Fi), a webcam is generally connected by a USB cable, or similar cable, or built into computer hardware, such as laptops. Their most popular use is the establishment of video links, permitting computers to act as videophones or videoconference stations. Other popular uses include security surveillance, computer vision, video broadcasting, and for recording social videos.
CCTV vs. IPTV:
CCTV refers to video cameras for surveillance purpose.
IP TV is watching TV on the internet.
History of CCTV:
The first CCTV system was installed by Siemens AG at Test Stand VII in Peenemünde, Germany in 1942, for observing the launch of V-2 rockets. The noted German engineer Walter Bruch was responsible for the technological design and installation of the system. In the U.S. the first commercial closed-circuit television system became available in 1949, called Vericon. Very little is known about Vericon except it was advertised as not requiring a government permit. The earliest video surveillance systems involved constant monitoring because there was no way to record and store information. The development of reel-to-reel media enabled the recording of surveillance footage. These systems required magnetic tapes to be changed manually, which was a time consuming, expensive and unreliable process, with the operator having to manually thread the tape from the tape reel through the recorder onto an empty take-up reel. Due to these shortcomings, video surveillance was not widespread. VCR (video cassette recorder) technology became available in the 1970s, making it easier to record and erase information, and use of video surveillance became more common. During the 1990s, digital multiplexing was developed, allowing several cameras to record at once, as well as time lapse and motion-only recording. This increased savings of time and money and the led to an increase in the use of CCTV. Recently CCTV technology has been enhanced with a shift towards internet-based products and systems, and other technological developments.
In September 1968, Olean, New York was the first city in the United States to install video cameras along its main business street in an effort to fight crime. During the 1980s video surveillance began to spread across the U.S. specifically targeting public areas. It was seen as a cheaper way to deter crime compared to increasing the size of the police departments. Some businesses as well, especially those that were prone to theft, began to use video surveillance. Today, systems cover most town and city centers, and many stations, car-parks and estates.
From broadcast industry to CCTV:
Prevalence and market of CCTV:
There were about 25 million CCTV cameras in operation worldwide in 2002. The British Security Industry Authority (BSIA) estimated there are up to 5.9 million closed-circuit television cameras in the country, including 750,000 in “sensitive locations” such as schools, hospitals and care homes. The survey’s maximum estimate works out at one for every 11 people in the UK, although the BSIA said the most likely figure was 4.9 million cameras in total, or one for every 14 people. Using a more complex methodology than previous studies, the BSIA produced a high, low and medium figure for each sector of the economy and then added the number together to say that the low estimate is 4 million cameras, the medium estimate is 4.9 million and the high estimate is 5.9 million. Importantly, they were counting all CCTV surveillance cameras, regardless of whether they face the public or not. So a camera in a storeroom or other area that is seldom visited by anyone counts just as much as a camera looking at the pavement outside a shop. The UK has more CCTV cameras per head of population than any other country. Harrods London store has in excess of 500 CCTV cameras installed. London’s Metropolitan Police Force has approximately 200,000 cameras installed around the capital.
Britain the surveillance state:
Britain has one and a half times as many surveillance cameras as communist China, despite having a fraction of its population. In China, which has a population of 1.3 billion, there are just 2.75 million cameras, the equivalent of one for every 472,000 of its citizens. Britain has established itself as the model state that the Chinese authorities would love to have. It is estimated that Britain has 20 per cent of cameras globally and that each person in the country is caught on camera an average of 300 times daily. There are 70 times more privately owned surveillance cameras in the UK than government ones.
•An article written in The Telegraph (14th June 2013) titled ‘Britons embrace CCTV cameras’ revealed that in a survey questioning 6,000 adults in France, Germany, Spain, Sweden and the UK, Britain was found to have “the second highest number of people who felt that CCTV did not affect freedom, after Sweden.”
•The same survey revealed that 67% of people in Britain do not think that CCTV poses a problem; with 81% believing that it helps police fight crime.
•Following the riots in August 2011, BSIA member Synectics conducted a survey that revealed that 76% of individuals surveyed felt safer knowing that CCTV is in operation in public areas.
•62% of those surveyed also claimed that they would like to see more CCTV in their local area.
According to industry estimates, the global video surveillance market is expected to grow from $11.5 billion in 2008 to $37.7 billion in 2015. A 2013 New York Times/CBS poll found that 78% of respondents supported the use of surveillance cameras in public places, and authorities tend to point to spectacular successes — for example, crucial images cameras provided of the Boston Marathon bombing suspects or the identification of those responsible for the 2005 London attacks. The CCTV Market for the Global CCTV is expected to grow at the compound annual growth rate (CAGR) of around 14% during 2013-2017.
The human eye and its brain interface, the human visual system, can process 10 to 12 separate images per second, perceiving them individually. The threshold of human visual perception varies depending on what is being measured. When looking at a lighted display, people begin to notice a brief interruption of darkness if it is about 16 milliseconds or longer. Observers can recall one specific image in an unbroken series of different images, each of which lasts as little as 13 milliseconds. When given very short single-millisecond visual stimulus, people report duration of between 100 ms and 400 ms due to persistence of vision in the visual cortex. This may cause images perceived in this duration to appear as one stimulus, such as a 10 ms yellow flash of light immediately followed by a 10 ms blue flash of light perceived as a single green flash of light. Persistence of vision may also create an illusion of continuity, allowing a sequence of still images to give the impression of motion. However, persistence of vision, that is popularly taught as the reason for motion illusion, is in reality merely the reason that the black spaces that come between each “real” movie frame are not perceived, which makes the phi phenomenon the true reason for motion illusion in cinema and animation, including the phenakistoscope, zoetrope, and others. The phi phenomenon is the optical illusion of perceiving continuous motion between separate objects viewed rapidly in succession. The phi phenomenon is the apparent motion caused by a changing static image, as in a motion picture. A visual form of memory known as iconic memory has been described as the cause of this phenomenon. In the motion picture industry, where traditional film stock is used, the industry standard filming and projection formats are 24 frames per second (fps). Shooting at a slower frame rate would create fast motion when projected, while shooting at a frame rate higher than 24 fps would create slow motion when projected.
Eyes and cameras work in same fashion:
To see an object, light must fall on object and reflected light from object enters eyes and processed in visual cortex as image. Similarly, for image to develop in camera, light must fall on object and reflected light enters camera to fall on image sensor that convert incident photons into displacement of electrons due to photoelectric effect. The displaced electrons in image sensor would elicit change in voltage and consequent analog signal akin to incident light. This analog signal would be converted into image on a film. This is still image. When many still images are taken sequentially and seen by eyes sequentially, an illusion of motion is created in our brain due to phi phenomenon and that is what we call video. In contrasting persistence of vision theory with phi phenomena, a critical part of understanding that emerges with these visual perception phenomena is that the eye is not a camera. In other words vision is not as simple as light passing through a lens, since the brain has to make sense of the visual data the eye provides and construct a coherent picture of reality.
The lux is the unit of illuminance and luminous emittance, measuring luminous flux per unit area. The basic unit of light within the European Standards is the lux – the amount of visible light per square metre visible on a surface. In Europe this is measured with a lux meter although in the USA you would use a foot-candle meter as the lux is also equivalent to 1 lumen per square metre or 0.093 foot-candles. Although it may seem simplistic to say so, in addition to needing light of the correct quality from a well-directed source, cameras require light in the right quantity. This is not always easy to find! Available light in our everyday lives varies to a surprising extent. A bright sunny day may generate 100,000 lux while the average operating table will be bathed in 20,000 lux. A hotel kitchen may enjoy 1,000 lux, a normal office 500 lux and a bank counter 200 lux. Compare this to street lighting which is typically between 5 and 50 lux and full moonlight weighs in at 0.1 lux! It takes considerable technical knowledge, skill and experience to ensure that the right camera systems with the right components are properly located and calibrated to take full advantage of these widely varying lighting conditions which are, themselves, subject to fluctuation due to time, season, weather conditions and other contributing factors. The opportunities to get the right camera in the wrong place or the wrong camera in the right place are legendary. Specifications for video cameras such as camcorders and surveillance cameras often include a minimum illuminance level in lux at which the camera will record a satisfactory image. A camera with good low-light capability will have a lower lux rating. Still cameras do not use such a specification, since longer exposure times can generally be used to make pictures at very low illuminance levels, as opposed to the case in video cameras where a maximum exposure time is generally set by the frame rate.
Frame rate (also known as frame frequency) is the frequency (rate) at which an imaging device produces unique consecutive images called frames. The term applies equally well to computer graphics, video cameras, film cameras, and motion capture systems. Frame rate is most often expressed in frames per second (fps). Real time recording is about 25 to 30 fps. To calculate the fps per camera, take the total fps that the system could offer and divide it by the number of video inputs. For example, a 100 fps DVR (digital video recorder) with 4 video inputs would give 100/4, 25 fps per camera.
Light to video:
Light is energy in the form of electromagnetic radiation. The different forms of electromagnetic radiation all share the same properties of transmission although they behave quite differently when they interact with matter. Light is that part of the electromagnetic spectrum that can be detected by the human eye. Visible radiations are the wavelengths of light that are visible to the human eye and are from approximately 380 nm to 760 nm. Infrared light is considered to be wavelengths longer than 715 nm. As stated light is a form of electromagnetic radiation, its power is measured in Watts and its intensity measured in Watts per square meter (W/m^2). This goes for all wavelengths. The visible spectrum is, however, normally measured in lumens for power and intensity in lux. The lumen is related to perceived power or brightness and because of this, the relationship between lumens and Watts is dependent on wavelength. Lumen values diminish virtually to zero at infrared wavelengths. This is why it is not possible to express infrared radiation in terms of lux values. Only natural light provides absolutely even illumination, although it is of course affected by clouds and shadows. All forms of artificial light suffer from the fact that as the distance increases from the light source so the illuminance reduces. This is due to the inverse square law of illumination where the illuminance falls to a quarter of its value if the distance is doubled. This factor is particularly important in considering the light available for a camera. For instance a light source providing a level of 30 lux at 20 meters will provide 7.5 lux at 40 meters and only 3.3 lux at 60 meters. The other effect of this is that the wide range of light levels can cause problems with automatic iris lenses. Unless set up correctly, the foreground light will cause the iris to close and lose definition in the distance. The reverse is if the iris is set to the distant light level in which case there will be a lot of flare in the foreground. Another factor that affects the light level of an area is if the light is striking the surface at an angle. When light strikes a diffuse surface at an angle, the effective area of the surface is reduced proportionally to the cosine of the striking angle of incident light and the specific reflectance of target or scene. The sensor in a CCD (charged couple device) camera is composed of thousands of tiny photo-sensitive diodes, a camera with a resolution of 570 lines incorporates over 400,000 such diodes. Incidentally, all camera sensors are monochrome, colour is obtained by inserting red, green and blue filters (RGB wavelength regions) in front. This is why colour cameras have less resolution than monochrome cameras. Also due to the filters, colour cameras are not sensitive to infrared light. Therefore all the discussion on camera sensitivity and suitability for infrared illumination is confined to monochrome cameras. This is except for the Dual Mode cameras now becoming available which potentially offer the best of both worlds.
As an image is the recording of reflective light images, the amount of ambient light in the field of view determines the quality of the image being captures. For example, if a CCTV camera is mounted to capture the images of people coming into a store and if the store entrance is to the outside and exposed to sunlight, without the proper camera lens, at the time of the day when the sun is shining into the store, the quality of the images captured will be very poor. Similarly, where there is a low light situation, unless a type of lens which uses Infrared technology and contains a wide angle view is installed, the images will be extremely poor. The use of vari-focal lens permits adjustments to the camera lens to increase or reduce the amount of light coming into the camera and to thereby improve the quality of the images recorded.
An understanding of the principles of light is important to the design of CCTV systems because without adequate light there can be no pictures. What is ‘adequate light’ is dependent on many factors, some of which have already been mentioned in the specification of cameras and lens. The most important aspects of light affecting the design of CCTV systems are: Light level in lux; Reflectance and the wavelength of the light source. The light level and reflectance are interrelated and decide the camera sensitivity. The wavelength must be related to the spectral response of the camera.
Analog cameras tend to have older and less expensive sensors in them, so they need more light. A lot of Analog cameras have built in “illuminators” (invisible infra-red LED’s around the lens to help light up objects in front of the camera), so these would consume more power than a newer more efficient network camera. Alternatively, more lights can be left on at night to help the analog cameras work better but this is even worse from a power stand point.
Need for CCTV lighting:
1. Most crime occurs during darkness
2. All cameras need light to see
3. Regular street lighting is not good enough
4. Provide evidence for judicial purposes
5. IP cameras need more light
6. Megapixel cameras need more light
7. Video analytics only works with good clean images
LED (light emitting diode) light and CCTV:
With ongoing product development and improvements based on frequent night-test sessions, LED illuminators have been refined to provide the even quality illumination that is exactly what CCTV cameras need. With the right products the light can be easily targeted and adjusted to give both the correct range (typically up to 370m+) and angle of coverage (typically anything from 10-180°) for each application. LED lights are also highly flexible in use; they start up immediately (with no warm up period) and so can be used for active warning systems, and for intelligent detector-driven CCTV applications. At night or in low light conditions, CCTV lighting can really enhance images, meaning that you can still monitor activity in your chosen areas with no compromise on picture quality.
Infrared (vide infra):
Infrared illuminators are designed to work in conjunction with B&W or Day and Night Cameras providing a light invisible to the human eye but fully visible to the CCTV camera. They pick up images clearly without attracting attention to the camera as there’s normally nothing more than a very dim glow on the unit.
LED (light emitting diode) based white-light illuminators deliver perfect white-light for use with colour cameras. LED white-light simulates daylight unlike the more standard incandescent sources, and it will illuminate your images, brightening any chosen area. Whether you want to deter potential problems or offer support in darkened areas, this is a great solution.
The figure above shows that White Light LED technology allows accurate colour image capture at night and ensures that the CCTV system works at its best 24/7. White Light LED products can be used as a powerful deterrent.
Remember, infrared LED illumination provides capture of image at night without notice of intruder and white-light LED illumination provides capture of image in color at night with notice of intruder. Infrared illumination can catch crime at night while white light illumination can deter crime at night.
Analog (analogue) and Digital Signals:
When an image is being captured by a camera, light passes through the lens and falls on the image sensor. The image sensor converts the received amount of light into a corresponding number of electrons. The stronger the light, the more electrons are generated. The electrons are converted into voltage which varies from positive to negative and back again in a sine-wave-shaped pattern. An analog signal represents the information it is intended to convey by presenting a continuous waveform analogous to the information itself. If the information is a 1000 Hertz sine-wave tone, for example, the analog signal is a voltage varying from positive to negative and back again, 1000 times per second, in a sine-wave-shaped pattern. A digital signal, unlike an analog signal, bears no superficial resemblance to the information it seeks to convey. Instead, it consists of a series of “1” and “0” bits, encoded according to some particular standard, and delivered as a series of rapid transitions in voltage. Ideally, these transitions are instantaneous, creating a “square wave.” Electrons don’t know whether they’re “digital” or “analog.” But that does not mean that digital and analog signals behave alike.
An analog signal is an ‘any time continuous signal’ where some time varying features of the signal is a representation of some other time varying quantity. It differs from a digital signal in that small fluctuations within the signal are meaningful. Analog is usually thought of in an electrical context, however mechanical, hydraulic and other systems might also transmit analog signals. Each stage of the process, from camera through cabling, switching/multiplexing, recording and finally display, involves a transfer of this signal with unavoidable loss in both accuracy, and quality. On the other hand, digital signals are represented by binary numbers, through a series of 0’s and 1’s in relevant order, and this precision of quantity is measured in bits. A digital signal is transferred through each of these stages with total precision, because each tiny element of the signal is represented by a number. Transmissions are coded, so that errors can be detected and corrected, or part of the signal can be repeated. Ideally, video signals need to be generated in a digital format, and then processed from start to finish in the digital domain to avoid the initial loss of accuracy that would occur were the signal initially to be converted from analogue input into. This is exactly the trend current CCTV systems are following.
Camera and Video:
The starting point for any CCTV system must be the camera. The camera creates the picture that will be transmitted to the control position. Apart from special designs CCTV cameras are not fitted with a lens. The lens must be provided separately and screwed onto the front of the camera. There is a standard screw thread for CCTV cameras, although there are different types of lens mounts. Not all lenses have focus and iris adjustment. Most have iris adjustment. Some very wide angle lenses do not have a focus ring. The ‘BNC’ plug is for connecting the coaxial video cable. Line powered cameras do not have the mains cable. Power is provided via the coaxial cable. Cameras can be internal or external, highly visible or covert. They can be static or fully controllable/movable from a remote location. You can have one camera or hundreds; you can record for one day or 21 days. With a suitable internet connection, you can even view your property when you are abroad. There are many types of CCTV cameras. They can be categorized by the types of images they are able to capture, the amount of frames they can take per minute, the type of connection to the monitor or video recording device, whether they are able to move position, and special functions they can provide.
You have the choice of a mono, colour or colour/mono CCTV camera, which each have their advantages. Mono cameras are only able to capture images in black and white, but are the cheapest option and ideal for those on a budget. Colour CCTV cameras are better for use as evidence as they will display a full colour image, making it easier to identify people or objects in the image. For example, you will be able to see the hair colour and clothing colour of a suspect in a robbery. Colour/mono cameras however are able to capture full colour images during the day and then monochrome images at night when a standard colour camera would struggle to capture anything.
Some types of camera:
◦Infrared Day/Night (color during the day, black and white and infrared viewing in complete darkness.)
◦Dome Security Cameras (a favorite for indoor applications)
◦Bullet Security Cameras (size of a finger “thus called bullet.”)
◦Box Security Cameras (you see in banks a lot)
◦PTZ Security Camera (Controllable Pan Tilt Zoom Cameras such as the airport)
◦Hidden Cameras (smoke detector, motion sensor, clocks)
Some cameras can be used outdoor or indoor. This will be specified on the product. Never use an indoor camera outdoor or there will eventually be video issues.
Most security cameras have a fixed 6mm lens that allows you to see facial features out to about 30 feet and provides a 56 degree angle of view. Resolution levels for black and white security cameras are about 400 lines, any higher and the benefits are minimal. For color cameras, the higher the resolution the better. Infrared security cameras are also very popular as they allow an image to be seen in little or no lighting conditions. Most infrared security cameras are bullet style and can be used inside or out. The cameras have infrared lighting installed around the outer edge of the lens which allows the security camera to see in no light. Varifocal camera lenses allow you to adjust the focus from 5 to 50 mm. These lenses can be used inside only unless you put it in special housing for outdoor use. Dome security cameras basically provide a different look. Everyone has seen these security cameras in businesses and stores. Because of its shape, it is difficult to tell exactly where the camera is aiming unless you see it up close. Dome cameras are generally used inside buildings.
To provide optimum performance neither too much nor too little light should fall on the camera sensor. This can be adjusted by means of the lens iris. A smaller iris opening offers greater depth of field and better focus, but the reduced amount of light admitted into the camera results in poor quality images in low lighting levels. A fixed iris lens offers no adjustment to different lighting conditions, so is therefore limited in use and not suitable for applications where fine detail is consistently required. A manual iris can be adjusted at the time of installation, allowing an optimum picture to be obtained for a fixed lighting level. These lenses are best suited to indoor applications, where the lighting level is controllable and consistent. Both manual and fixed iris lenses can be used with cameras which offer a feature known as ‘electronic iris’ – an on-board technology to effectively reduce the sensor exposure to compensate for the lack of iris control. This can be cost effective, but does not provide the increased depth of field offered by a correctly sized iris. For external use (where conditions generally vary the most), an automatic iris lens offers the best performance, as the iris aperture automatically adjusts to create the optimum image by monitoring the output signal from the camera. There are a number of different lens types offering this method of iris control. The original design for automatic iris (Al) lenses was wholly self-contained, with the image analysing technology built into the lens and an iris that was adjusted by servomotors.
The function of lens of CCTV camera is to focus incoming light on image sensor. The CCTV lens performs two main functions. First it determines the scene that will be shown on the monitor; this is a function of the focal length. Second it controls the amount of light reaching the sensor; this is a function of the iris. The human eye is an incredibly adaptable device that can focus on distant objects and immediately refocus on something close by. It can look into the distance or at a wide angle nearby. It can see in bright light or at dusk, adjusting automatically as it does so. It also has a long ‘depth of field’; therefore, scenes over a long distance can be in focus simultaneously. It sees colour when there is sufficient light, but switches to monochrome vision when there is not. It is also connected to a brain that has a faster updating and retentive memory than any computer. Therefore, the eyes can swivel from side to side and up and down, retaining a clear picture of what was scanned. The brain accepts all the data and makes an immediate decision to move to a particular image of interest, select the appropriate angle of view and refocus. The eye has another clever trick in that it can view a scene of great contrast and adjust only to the part of it that is of interest. By contrast, the basic lens of a CCTV camera is an exceptionally crude device. It can only be focused on a single plane, everything before and after this plane becoming progressively out of focus. The angle of view is fixed. At any time, it can only view a specific area that must be predetermined. The iris opening is fixed for a particular scene and is only responsive to global changes in light levels. Even an automatic iris lens can be only be set for the overall light level, although there are compensations for different contrasts within a scene. Another problem is that a lens may be set to see into specific areas of interest when there is much contrast between these and the surrounding areas. However, as the sun and seasons change so do light areas become dark and dark areas become light. The important scene can be ‘whited out’ or too dark to be of any use. A controversial but important aspect of designing a successful CCTV system is the correct selection of the lens. The problem is that the customer may have a totally different perspective of what a lens can see compared to the reality. This is because most people perceive what they want to view as they see it through their own eyes. Topics such as identification of miscreants or number plates must be debated frequently between installing companies and customers. There are two other main factors that must be considered when selecting the most appropriate lens for a particular situation. The focal length and the type of iris control. Within each of these factors, there are other features that will also need to be considered. Lenses may be obtained with all combinations of focal length and iris control. The selection will depend on the site and system requirement. A zoom lens is one in which the focal length can be varied manually or using motor over a range.
Focal length of lens:
When rays of light pass through a convex lens, they tend to converge at a single point at some distance ahead of the lens. This distance between the lens and the point where they focus is known as the focal length. In case of a CCTV camera, the lens focuses the rays at a point where the sensor is placed. The combination of the focal length of the lens and the size of the sensor determine the field of view of the CCTV camera. The shorter the focal length, the wider the field of view, and vice versa. A short focal length (e.g. 3.6mm) represents a wide angle of view while a long focal length (16mm) represents a narrow angle of view. The size of the camera’s CCD image device will also affect the angle of view. CCTV Cameras come in different chip sizes – 2/3″, 1/2″, 1/3″ and 1/4″. The smaller the CCD Chip – the narrower the angle of view.
Wide Angle Lenses:
Wide angle lenses have many advantages for CCTV and IP video surveillance. The first advantage is wide field of view. The second advantage is good low-light performance. And last but not least, wide angle lenses provide good depth of field as compared to telephoto lenses. However these advantages do come with a few drawbacks as well such as the possible geometrical distortion which appears as visible curvatures at the edges of a camera image and higher requirements for the camera resolution. Hence it is important to maintain a proper balance between the wide field of view and possible drawbacks of wide angle lenses.
Field of View:
The CCTV Camera must be placed in a position to permit it to capture the images wished to be captured. This is called the “field of view”. If the field of view is in a confined space directly in front of the camera, a particular lens to capture these relative close images will be used. However, if the field of view extends a distance away from the camera such as in the length of a store aisle, to record images with sufficient resolution to utilize them properly, a CCTV camera with a lens to capture this field of view should be used.
Depth of Field:
The Depth of Field is the distance within which objects in a picture are in focus as seen in the figure below.
A large Depth of Field means almost all objects in the Field of View are in focus.
A small Depth of Field means only a small section of the Field of View are in Focus.
The following factors can lead to a greater Depth of Field: using a Wide Angle Lens, High F-Stop, using an Auto Iris.
Range of CCTV camera:
IR range is a largely made up number based around how far away from the camera Infra red light can be detected. It has nothing at all to do with the effective range at which detail can be filmed. The distance at which detail can be captured using a camera is its optical range. Some PTZ cameras have 10 km range. The table below shows an approximate guide to the optical range of different lens cameras i.e. the distance at which a number plate or a person can be identified.
|2.8 mm lens||1.5 meters|
|3.6 mm lens||3 meters|
|6 mm lens||5 – 6 meters|
|9 mm lens||8 – 9 meters|
|12 mm lens||10 meters|
|22 mm lens||15 meters|
|60 mm lens||50 meters|
What is C and CS mounts?
It refers to the 2 different standards of CCTV camera lens mount. The difference between the two is the distance between the lens and the image sensor. C mount: 17.5mm, CS mount: 12.5mm. Cameras and lenses nowadays are generally CS mount rather than C mount. With CS mount cameras, both types of lenses can be used. However, the C mount lens requires an additional 5mm ring to be fitted between the camera and lens to achieve a focused image. With C mount cameras it is not possible to use CS mount lenses as it is not physically possible to mount the lens close enough to the image sense to achieve a focused image. The advantage to C-mount security cameras is that the lens can be changed. You’ll want a special camera lens if you need to see further than 35 ft. The colour C-mount security camera allows you to change lenses on the camera giving you the ability to zoom into a particular area.
A pan–tilt–zoom camera (PTZ camera) is a camera that is capable of remote directional and zoom control. Surveillance cameras of this type are often connected to a digital video recorder which records the full field of view in full quality. Pan/Tilt/Zoom or PTZ cameras permit the manipulation of the camera to change the camera’s field of view. This manipulation is done mechanically by using a control device called a “joy stick”. By using the joy stick, the viewer can change the camera’s field of view to track a person moving through the store. With the advent of digital camera technology, digital cameras are available which perform a similar function, but do so using software rather than mechanically manipulating the camera.
An innovation to the PTZ camera is a built-in firmware program that monitors the change of pixels generated by the video clip in the camera. When the pixels change due to movement within the cameras field of view, the camera can actually focus on the pixel variation and move the camera in an attempt to center the pixel fluctuation on the video chip. This process results in the camera following movement. The program allows the camera to estimate the size of the object which is moving and distance of the movement from the camera. With this estimate, the camera can adjust the cameras optical lens in and out in an attempt to stabilize the size of pixel fluctuation as a percentage of total viewing area. Once the movement exits the cameras field of view, the camera automatically returns to a pre-programmed or “parked” position until it senses pixel variation and the process starts over again.
Eye in the sky (camera):
The eye in the sky is a term given to casino and other commercial security closed circuit cameras. In casinos, they are positioned to monitor seats, tables, hallways, restaurants, and even elevators closely. The functional component is a PTZ camera. These cameras often help casino officials judge whether the person is card counting, which is popular in blackjack or past posting, which is popular in roulette. In case a crime or a cheat is detected after the fact, the casino employees can review the recorded tapes and find the culprit. The casino cameras are adjusted to focus on certain suspicious players by security workers in a separate casino room with banks of security monitors.
Housings, in essence are casings used to protect Cameras from a variety of conditions, dependent on the environment in which they are mounted. At first sight, most Camera Housings may seem similar. In practice to ensure the optimum appearance and performance of appropriate for a Camera installation, a number of factors have to be taken into consideration:
2. Risk of vandalism.
3. The total load weight of the housing and constituent elements (including Camera, Lens and any other equipment encased within, the hanging bracket and fixing surface)
4. The housing chosen has sufficient physical space for the Camera, Lens (which may have to be changed at a later stage), electrical wiring and enough room to make the connections and allow for future maintenance.
5. Try to aluminium or rust proof products. Steel is more vulnerable to the elements and will rust in time!
Housings should only be mounted onto load bearing points.
Before I go to CCTV camera, let me discuss standard film camera and movie camera:
How ordinary film cameras work:
When you take a photo, the shutter lets light enter from the lens and expose the film. A film is a long spool of flexible plastic coated with special chemicals (based on compounds of silver) that are sensitive to light. It is an analog medium because chemical change is proportional to the amount of light absorbed by each light-sensitive silver halide crystal.
Film photo to digital photo:
You can take a photograph using a conventional film camera, process the film chemically, print it onto photographic paper and then use a digital scanner to sample the print (record the pattern of light as a series of pixel values).
Classic movie cameras:
A basic movie camera is like a standard film camera that takes a photograph on to plastic film every time the shutter opens and closes. In a standard film camera, you have to wind the film on so it advances to the next position to capture another photograph. But in a movie camera, the film is constantly moving and the shutter is constantly opening and closing to take a continuous series of photographs—about 24 times each second.
The first CCTV cameras to be used were based around special vacuum tubes with a light sensitive coating on one end. Light striking this coating caused electric current to flow down the tube, proportional to the amount of light falling at each point on the coating. The circuits of the camera then converted the current to the video signal. This was a good initial design and gave cameras that had good sensitivity and resolution. However the cameras were bulky and the tubes had a limited life span, requiring regular, expensive tube changes. CCD cameras, when introduced, were smaller, lighter and required practically no maintenance. This has led to their widespread replacement of tubed cameras in CCTV systems, where CCD cameras are now used in practically all new installations. For this reason, no further discussion of tubed cameras will be made in this article.
An image sensor is a device that converts an optical image into an electronic signal. It is used mostly in cameras, camera modules and other imaging devices. Early analog sensors were video camera tubes; currently used types are semiconductor charge-coupled devices (CCD) or active pixel sensors in complementary metal–oxide–semiconductor (CMOS) or N-type metal-oxide-semiconductor (NMOS, Live MOS) technologies. At its most basic level, a camera has a series of lenses that focus light to create an image of a scene. But instead of focusing light onto a piece of film, video is focused onto a Charge Coupled Device that records light electronically. The semiconductor device (CCD) measures light with a half-inch panel of 300,000 to 500,000 tiny light-sensitive diodes called photosites. Each photosite measures the amount of light (photons) that hits a particular point, and translates this information into electrical charges. A brighter image is represented by a higher electrical charge, and a darker image is represented by a lower electrical charge. But measuring light intensity only gives us a black-and-white image. To create a color image the CCD has to detect not only the total light levels, but also the levels of each color of light. Since you can produce the full spectrum of colors by combining the three colors red, green and blue, the CCD only needs to measure the levels of these three colors to be able to reproduce a full-color picture.
Ironically, although CCD stands for “Charge Couple Device” and CMOS stand for “Complementary Metal Oxide Semiconductor” but actually neither CCD nor CMOS have anything to do with image sensing. The actuarial sensor is a device called “Photo Diode” Both CCD sensor and CMOS sensor (as so called), are actually using same kind of sensor called Photo diode. Photo diode is a P N junction diode that will convert photon of the light that is bombing the junction into proportional amount of electron. The amount of electron are them calculated and read as voltage of signal. The more the light that entering the photo diode the more the electron generated and the higher the voltage output from the sensor. CCD actually is only the technology to store the electron charge and the method to move these charges out of photo sensor in an organized way. CMOS actually is only a technology to make transistor on silicon wafer, and have no further meaning. Sensor being called CMOS sensor was a convenient way to discriminate it from CCD sensor and have nothing to do with the real ways that the sensor handling image. CMOS sensor convert electron generated by photo diode into voltage signal immediately without complicate process hence it is much faster. This good point makes CMOS sensor very useful for fast frame camera, the frame speed can be as high as 400 ~2000 frame/sec. This point makes it very good for high speed moving object survey. Since CCD image sensors charge all light particles at once, they use 100 times more power than CMOS sensors. This means the battery life of cameras with CCD sensors will be much lower than those with CMOS sensors. CCD image sensors also cost more to manufacture since they are a very complex part of the camera, which in turn makes cameras with CCD sensors more costly than CMOS cameras. Experts and hobbyists have never been able to agree completely on which image sensor is the best. While there are pros and cons to each, it really comes down to personal preference, and with the use of photo-editing software, pictures from either type of camera can come out perfect.
A lens focuses light onto the surface of the CCD image sensor. The areas of light and dark are sensed by individual photo-diodes, which build up an electrical charge proportional to the light. That is to say that the brighter the light on an individual photo-diode the bigger the charge developed. These photo-diodes are arranged in a matrix of rows and columns and are given the name picture cells or Pixels. The charge is removed from each pixel by rows of CCD cells. These CCD rows are like ladders for charge, enabling step-by-step the charge on each pixel, and consequently the light level on it, to be read off by processing electronics. An amplifier is needed to boost the signal from the CCD sensor electronics up to the level where it can be used on a monitor. A synchronising generator is also used in the CCD camera to generate the signals that read the light level charge off the CCD and the synchronisation pulses used by the video monitor to re-create the image. The mixer section combines the video and synchronisation signals to produce the composite video signal used by the monitor.
Colour CCD Cameras:
Colour CCD cameras are basically the same as monochrome cameras. However, there are additional components that have important effects on the performance of the camera. Light passes through the lens and through a colour correction filter on to the CCD. The CCD is sensitive to infrared light, which is present in normal daylight. This infrared light produces false signals from the CCD that affects the purity of the colours reproduced by the camera. The colour correction filter removes the infrared light before it hits the CCD and ensures the colour purity of the camera. However, it also means that infrared illuminators cannot be used with normal colour cameras as the colour correction filter removes all the lighting created. The actual CCD image sensor comprises of an array of pixels like a monochrome camera. However, each pixel is subdivided in to three smaller light sensitive areas that are constructed to be sensitive to red, green and blue light respectively. Consequently the pixels are larger in size than for monochrome CCDs and the number of pixels which can be fitted on to a colour CCD of a given size is less than a monochrome CCD of equal dimension. This is why, generally, monochrome cameras still have resolution which is higher than colour cameras. The colour correction filter and colour sensitivity of the pixels also tend to make colour cameras less sensitive to light that monochrome cameras. Typically, colour cameras have sensitivities between 1 lux and 2.5 lux whereas monochrome cameras have sensitivities between 0.01 lux and 0.1 lux. The separate brightness signals for red, yellow and blue are amplified separately and the used by signal processing circuits to produce the luminance (Y) signal and the chrominance (C) signal. The Y and C signals are then combine with the composite sync pulses to produce a composite colour video signal. Many colour cameras also feature a separate connector where the Y and C signals are output separately for connection to Super VHS video recorders and monitors, for improved resolution.
Monochrome or Colour?
The human eye remembers and recalls things better if they appear in colour – it’s easier to track down a brown-haired person wearing a red sweater and blue jeans than a dark, grey-clad figure that would be produced in monochrome. Colour cameras carry an additional premium in price compared with monochrome cameras. But they are also less sensitive making night usage an impractical option unless good lighting is available. Monochrome cameras can offer Infra Red (IR) sensitivity allowing their use with covert IR illumination possible. This can be particularly useful where planning permission makes extra lighting impractical or the security requirement is such that intruders should not be alerted to the existence of CCTV surveillance.
Analog and digital camera:
Video cameras are either analogue or digital, which means that they work on the basis of sending analogue or digital signals to a storage device such as VCR (for analog signals) or DVR, desktop computer/ laptop computer for digital signals. However, when ADC (analog digital converter) is used, analog signals are converted into digital signals and stored on DVD or computer. These can be subdivided further into medium resolution monochrome or color, high resolution monochrome or color, day/night cameras that provide color in the day and monochrome at night. Currently, most CCTV applications use analog baseband composite video.
Conventional CCTV camera (conventional analog camera):
In conventional CCD cameras the functions of amplification, signal processing and mixing are carried out by analogue circuits, which work on changing the voltages of the signals by various means. Adjustments to picture quality are made by small adjustable resistors which are set up to give the best overall performance across a range of camera operating conditions (light levels etc.) This approach is very cost effective and gives good quality pictures in most lighting conditions. However, these adjustments are, at best, a compromise and the effects of tolerances in the values of the electronic components and changes over the lifetime of the camera can cause the quality of pictures obtained from the camera to vary greatly.
From analog camera (conventional CCTV camera):
1. Can record straight to a VCR which is able to record analogue signals as pictures.
2. Analogue signals can also be converted into a digital signal to enable the recordings to be stored on a PC as digital recordings. In that case the analogue video camera must be plugged directly into a video capture card in the computer, and the card then converts the analogue signal to digital. These cards are relatively cheap, but inevitably the resulting digital signals are compressed 5:1 (MPEG compression) in order for the video recordings to be saved on a continuous basis.
3. Another way to store recordings on a non-analogue media is through the use of a digital video recorder (DVR). Such a device is similar in functionality to a PC with a capture card and appropriate video recording software. Unlike PCs, most DVRs designed for CCTV purposes are embedded devices that require less maintenance and simpler setup than a PC-based solution, for a medium to large number of analogue cameras.
4. Some DVRs also allow digital broadcasting of the video signal, thus acting like a network camera. If a device does allow broadcasting of the video, but does not record it, then it’s called a video server. These devices effectively turn any analogue camera (or any analogue video signal) into a network TV.
You can also have analog video output from DSP camera (vide infra) and that is also analog camera but signal processing is digital and not analog. In conventional CCTV camera, signal processing is analog.
An analogue / HD-SDI camera just converts light signals into electrons and sends the electronic signal to the recorder to do arithmetic and storage. High-definition (HD) video is video of higher resolution and quality than standard-definition. While there is no standardized meaning for high-definition, generally any video image with more than 480 horizontal lines (North America) or 576 lines (Europe) is considered high-definition. Serial Digital Interface (SDI) is a standard for digital video transmission over coaxial cable. The most common data speed is 270 megabits per second (Mbps). However, speeds of up to 540 Mbps are theoretically possible. Standard 75-ohm cable is used. This is the same type of coaxial cable used in most home television (TV) installations.
Today, most digital still cameras use either a CCD image sensor or a CMOS sensor. Both types of sensor accomplish the same task of capturing light and converting it into electrical signals. Each cell of a CCD image sensor is an analog device. When light strikes the chip it is held as a small electrical charge in each photo sensor. The charges are converted to voltage one pixel at a time as they are read from the chip. Additional circuitry in the camera converts the voltage into digital information. Virtually none of these cameras are truly digital – they merely have internal digital processing to produce a better picture, alternatively a digital interface for camera control, but they do not produce a true digital image output. True digital cameras (a type of DSP camera discussed vide infra) discard the normal analogue video standard, and at the same time all the problems of fixed frame rate, interlacing, interlace motion-blur, limited TV-line resolution, and loss of signal quality over distance. Digital cameras will produce a digital signal with a frame rate and resolution most suited to the application, and can vary this according to immediate needs. These cameras can switch rapidly from a high-frame rate, medium-resolution image, to very high-resolution snapshots, or to low frame rate, low-resolution output for video transmission over phone lines. By using non-interlaced progressive scanning, digital cameras immediately double the available vertical resolution for recording purposes. Digital cameras will also offer far more than just better resolution and image quality – they will be intelligent. Their on-board processors and memory storage will mean that, with suitable programming, they could switch on lights, detect motion, trigger alarms, open gates, close doors and record pre- and post-alarm images when required. They will also be capable of controlling their own Pan Tilt and Zoom (PTZ) mounts, triggering automatic wash/wipe functions(to clean camera lenses), and even remind system managers when scheduled maintenance is due.
Typical CCTV analog video signal:
CCD and CMOS imagers both depend on the photoelectric effect to create electrical signal from light. Both types of imagers convert light into electric charge and process it into electronic signals. Figure below shows a typical CCTV analog video signal. This is commonly known as the composite baseband video signal because the synchronising and video information are combined into a single signal without a modulated radio frequency carrier. Maximum light will produce a maximum voltage and therefore a white level. No light will produce no voltage and therefore a black level. In between these will be shades of grey, and this is the luminance information of a video signal. In the case of a color camera, the chrominance and color burst signals are superimposed onto the luminance signal to carry the color information. The total voltage produced is 1 volt peak-to-peak (Vpk-pk), from the bottom of the sync pulse to the top of the white level. The luminance portion of the signal is from 0.3 volt to 1 volt (0.7 volt maximum).
Fundamentals of analog video:
Video signals are the signals used to send closed circuit television pictures from one place to another. Television (TV) is literally, tele-vision, a means of viewing one place from somewhere else. The word video comes from the Latin verb Videre, to see. A television picture is made up from a number of horizontal lines on the television screen, which are laid down, or scanned, from the top to the bottom of the television screen. There are now only two standards for TV pictures in general use, 525 lines in the USA (EIA) and Japan and 625 lines elsewhere (CCIR). The descriptions that follow are based on the 625-line system. The number of lines describes how each still picture is created, but a television picture is made up from a number of still pictures displayed every second. If a series of still images is presented at a rate of about 14 per second, an impression of continuous movement will be perceived. This, however, would give rise to a very distracting flicker. If the rate were increased to 24 images per second, the flicker would be almost unnoticeable. Increasing this to 50 images per second would eliminate noticeable flicker. To transmit 50 complete images per second would be needlessly complex and expensive to produce. The solution is to adopt what is known as interlaced scanning. Instead of scanning the full 625 lines 50 times a second, 312.5 lines are scanned 50 times a second. Therefore, one scan produces 312 1/2 lines from the top to the bottom of the picture. This is known as one field. The next scan is arranged to start at a precise position exactly between the lines of the first scan, so that the lines of the second field interlace, like fingers, between the lines of the first field. In this way, a complete frame of video is created made up from two fields. The CCD is scanned across and down exactly 312.5 times (for a 625-line system) and this creates a video field. A second scan of 312.5 lines is exactly 1/2 a line down and interlaced with the first scan to form a picture with 625 lines. This is known as a 2:1 interlaced picture. The combined 625-line is known as a video frame and made up from two interlaced fields. Typical camera resolution is 350 TV lines, with high resolution cameras producing better than 450 lines. On a TV screen, the phosphor on the screen continues to glow from the first scan while the second scan is being displayed. In this way, although only 25 complete pictures (frames) are presented per second the screen is scanned 50 times (fields) per second. The result is to achieve a flicker rate of 50 Hz (cycles per second) while only using a bandwidth for 25 frames per second. The relationship between the length of the horizontal lines and the height of the picture is always the same and is known as the aspect ratio. The signal used to carry the scanning pictures from one place to another is called the video signal. A voltage is generated proportional to the brightness of the image at any point on a horizontal line. For the brightest parts, corresponding to a white area, a level of one volt is produced; this is the white level. For the darkest parts corresponding to a black image, a voltage of approximately 0.3 volts is produced; this is the black level. Between these levels, the camera will produce a voltage proportional to the shade of grey of the image. CCTV (Closed Circuit TV) uses one or more video cameras to transmit video and sometimes audio images to a monitor, set of monitors, or video recorder. The difference between CCTV and standard TV is that standard TV openly broadcasts signals to the public. CCTV is not openly transmitted to the public.
The bandwidth required to transmit this signal ranges from DC to 8 MHz for the three main video standards: NTSC (National Television System Committee), PAL (Phase Alternate Line) and SECAM (Sequential Color and Memory). The NTSC format was developed in the US and is used in most of the Americas (North/South/Central), Japan, Korea, Taiwan and Philippines. It utilizes a bandwidth of 6 MHz. The PAL format was developed in Europe and is used in most of Europe, Asia and Africa, and utilizes a bandwidth of 8 MHz. The SECAM format was developed in France and is used primarily in France and some eastern European countries (Bulgaria, Czech Republic and Hungary), and also utilizes a bandwidth of 8 MHz.
NTSC has the colour video signal television standard: 525 lines, 60Hz while PAL has the colour video signal television standard: 625 lines, 50Hz
Television lines (TVL) is a specification of an analog camera’s or monitor’s horizontal resolution power. It is alternatively known as Lines of Horizontal Resolution (LoHR). The TVL is one of the most important resolution measures in a video system. Traditionally we have measured the resolution of analogue CCTV cameras in TeleVision Lines (TVL). This measure counts the number of vertical lines that can be resolved across the screen. TVL is defined as the maximum number of alternating light and dark vertical lines that can be resolved per picture height. A resolution of 400 TVL means that 200 distinct dark vertical lines and 200 distinct white vertical lines can be counted over a horizontal span equal to the height of the picture.
Resolution of analog image:
Resolution can be defined as the fineness of detail that can be distinguished in an image. In CCTV cameras, resolution is measured in TV Lines (TVL). A higher number of TVL means that a camera will be able to render images with more detail. However, TVL is not the sole factor that determines the quality of the final output. For example, the resolution does not affect the color reproduction of the camera. The monitoring device and the video processing of the DVR also impact the final output. Figure below is a comparison of different TVL resolutions.
Typical camera resolution is 350 TV lines, with high resolution cameras producing better than 450 lines. Note that resolution costs money! There are now colour cameras that instead of superimposing the chrominance onto the luminance signal, provide the chrominance as a separate signal. This is known as Y/C separation and requires two coaxial cables from the camera to carry each signal separately. The effect of this technique is to increase the bandwidth and therefore the resolution, typically to better than 500 TV lines.
DSP (digital signal processing) camera:
In DSP cameras digital circuits, as shown in figure below, carry out the signal processing and mixing. The signals from the CCD are connected to an analogue to digital converter (ADC). This converts the brightness level from each point into a number. In this way, the entire picture captured by the CCD at any moment is represented by a group of numbers. These numbers are processed at high speed by the digital signal processor, which does mathematics on the numbers in order to produce the video signal at the output of the camera. The digital signal processor gives the other name used for digital cameras, DSP. The composite video signal or Y-C video signal is produced by a digital to analogue converter (DAC) which takes the finished information from the digital signal processor and produces the composite video. Most DSP cameras still produce these analogue composite video and Y-C signals as this is currently the most popular format required by the other equipment in the video system; monitors, switchers, multiplexers, VCR’s etc. DSP cameras do have the possibility to produce the video signal in a digital form and it is likely that this will become popular when a worldwide standard is agreed for sending video pictures digitally in CCTV systems.
Digital signal processing (DSP) is the mathematical manipulation of an information signal to modify or improve it in some way. It is characterized by the representation of discrete time, discrete frequency, or other discrete domain signals by a sequence of numbers or symbols and the processing of these signals. A digital signal processor (DSP) is a specialized microprocessor (or a SIP block), with its architecture optimized for the operational needs of digital signal processing. The goal of DSP is usually to measure, filter and/or compress continuous real-world analog signals. Usually, the first step is conversion of the signal from an analog to a digital form, by sampling and then digitizing it using an analog-to-digital converter (ADC), which turns the analog signal into a stream of discrete digital values (as in IP camera). Often, however, the required output signal is also analog (as in analog camera), which requires a digital-to-analog converter (DAC). Even if this process is more complex than analog processing and has a discrete value range, the application of computational power to signal processing allows for many advantages over analog processing in many applications, such as error detection and correction in transmission as well as data compression.
DSP CCTV camera basics:
At first, IP/digital and analog cameras may seem more alike than they are different. Both cameras employ an analog image sensor, which is either CCD (charge coupled device) or CMOS (complementary metal oxide semiconductor). Virtually, all analog cameras use a CCD sensor and IP cameras can utilize either type. The analog signal from the sensor is then converted to digital form by an analog-to-digital converter and further processed by the camera’s onboard digital circuitry (DSP). Remember both IP camera and digital camera have digital signal processing and digital video output but IP camera additionally has embedded web-server with IP address to transmit video & audio through internet.
Hidden (covert) camera:
Hidden cameras can be integrated into any CCTV network, and often are. They allow users to record criminal behavior when criminals are on the lookout for standard security cameras. They can be more effective in capturing video evidence, since they are harder to avoid, but sacrifice the deterrent properties of traditional CCTV cameras. On the other end of the spectrum, dummy cameras are a low-cost deterrent device, appearing to be CCTV cams, often complete with blinking lights. Many small businesses use dummy cams as an extra measure of security.
The figure above shows Smoke-alarm covert camera.
Covert Cameras, in essence, are a means of offering surveillance of an undetected or more discreet nature. Suitable for use in a broad range of internal applications, these miniature cameras have been designed and developed to provide monitoring tools that are disguised in the form of everyday commercial and domestic objects. This ensures that they are able to blend inconspicuously into any background and consequently do not catch people’s attention. As a result, there are a number of state-of-the-art products which have been introduced into the market to meet security demands, varying from office clocks to Passive InfraRed (PIR) sensors, containing a minute camera within. These products are available in monochrome or colour versions and with optional audio. Covert cameras tend to be used where there is a requirement to achieve particular objectives. These tend to fall into the following categories:
A) Covert surveillance – where there is a requirement to monitor activities in a particular location, completely undetected, e.g. in areas of high security like jewellers and banks. They are also useful for back-up surveillance in installations where the primary CCTV equipment is of a more traditional nature, i.e. standard cameras. In this case Covert Cameras can operate as a back-up where primary cameras are disabled by an intruder.
B) Discreet/Unobtrusive surveillance – often there is a need for a surveillance system that is less conspicuous, not necessarily as an attempt to hide the fact that monitoring is taking place, but more from marketing or style considerations. When introducing a covert system, it is important to recognise that access to recorded material must be kept to a minimum to ensure the privacy of individuals who may appear. A responsible policy should be introduced to ensure that footage from covert cameras is used for the purposes it was intended.
Covert cameras are also subject to privacy considerations. No person shall use covert cameras and assume law enforcement powers in an endeavor to uncover an illicit activity, such as theft or pilfering, without involving the Police. Law enforcement authorities are the competent authorities vested with executive powers to investigate these offences and prosecute accordingly. Similarly, in case of an activity captured by a camera and which might lead to criminal charges, the relevant extract of the camera’s footage shall only be disclosed to law enforcement authorities and this subsequent to the filing of a Police report.
When it comes to protecting our homes or business, a careful assessment of the risks is required to identify whether the investment is worthwhile. In many situations, dummy CCTV cameras can be a highly effective deterrent to criminals – yet for a fraction of the cost of live surveillance systems. So what kind of premises are dummy cameras suited to? Essentially they can work as a deterrent internally or externally in any commercial, public or residential setting. They can be used to prevent intrusions, or to deter people from criminal activity while on the premises (e.g. shoplifters). The level of risk and threat will determine whether they offer sufficient protection. For businesses that stock high value goods for example, or that are subject to high frequency crime (such as petrol stations), investment in live CCTV is the sensible option. For many types of property however this expense is not justified and dummy cameras can provide the appropriate level of protection in combination with other measures. Opportunistic criminals (who account for the vast majority of crime) won’t strike if they think there is a chance they will be caught on camera – they simply move on to less well protected opportunities.
Night vision security camera:
For the human eye to see clearly, it must have adequate light. The same is true for security cameras. During the day, when office spaces and parking areas are properly lit by natural or florescent lighting, security cameras provide crisp images and colourful detail. At night, when those offices are closed and parking areas are dim, traditional security cameras may produce grainy video or video that is so dark the objects within the camera’s field of view are unidentifiable. In these types of security environments, installing a night vision security camera is the most economical way to produce quality 24/7 surveillance video.
Night vision technology is delivered using one of three methods, low-light, thermal imaging and infrared illumination.
Low-light imaging cameras work by using image intensifiers. The intensifiers enlarge the available light to produce an amplified image. This is achieved when the object of light focuses on the photocathode of an image intensifier. The electrons hit a phosphor screen and the image is created. Intensified camera systems use intensifiers to create a clear image during low-light situations. This allows the broader image of the low-light scene to be viewed. These cameras need some light available to produce an image. However, during low-light scenes, the image they produce is excellent. Low-light cameras have the ability to identify people. These cameras are a popular choice for homeowners because they are affordable.
Thermal imaging technology works by operating on the principle that objects radiate infrared energy because of its temperature. This type of security camera doesn’t require light to produce an image. The higher the temperature of the object, the more infrared energy is emitted. The thermal image is created by the infrared energy. Thermal images produce black images when objects are cold and white when they are hot. You can find some thermal cameras that project images in color. Thermal imaging cameras offer a high level of thermal sensitivity. These cameras are able to detect objects at a great distance. They are not dependent on light sources.
Infrared (IR) Illumination:
IR is the abbreviation for Infrared. IR cameras have image sensors that are designed to sense and process infrared light emitted from IR LEDs. Infrared illumination combines with motion detection technology to create an effective home security camera. When the camera detects movement, the infrared illumination lights up the scene and captures the images. These cameras can display detailed images such as numbers, lettering and objects. Infrared illumination cameras are inexpensive and don’t rely on ambient light to capture images. Combined with motion detectors, they do an excellent job of monitoring the perimeter of your home. Infrared illumination works with multiple LED lights to transmit images in black and white. Black and white produces a better quality image. What makes a night vision camera unique is the way it reacts to changing light conditions and makes use of available light. Like traditional security cameras, night vision cameras provide perfect color video during the day, or when optimal light is available. However, the difference between traditional security cameras and night vision cameras is evident at night. When there isn’t enough available light to produce a quality image, the night vision camera will automatically change from a color camera to an infrared receptive black and white camera. This change enables the night vision camera to produce crisp images and fine detail in any lighting condition – even in complete darkness! Night vision security cameras do this by using filters and enhanced video imaging technology to increase its sensitivity to infrared light. This type of light is near invisible to the human eye but provides the camera with enough ambient light for clear picture quality. Because infrared is not a visible source of light, it is particularly useful in covert security installations. In addition to producing clear and detailed video in low light levels, night vision cameras will allow you to see further into the darkness than a traditional security camera. When a traditional security camera is mounted outdoors near a light fixture, the camera can see only what is immediately within its view, a 15 to 20 foot area. This is because the camera must compensate for varying degrees of dark and light. When a night vision camera is installed with IR illuminators, the view can increase from 20 feet to more than 100 feet. Many night vision cameras have IR illuminators built-in to their camera housing. Depending on the needs of your environment, night vision cameras are available with housings for indoor or outdoor use and have more or fewer IR illuminators. The more IR illuminators available, the further into the darkness your camera will see. If a night vision camera is already installed, but does not have enough available light for the camera’s field of view, a separate IR illuminator can be installed near the camera to increase its viewing distance.
The figure below shows infrared technology used in the night vision cameras to view in absolute darkness:
The advantages of IR (infra-red) camera:
Infra-red illuminators provide IR light which is invisible to the human eye but visible to the CCTV camera. Because IR is invisible to the human eye it is ideal for covert surveillance; the camera can see, but the intruder cannot. Further, as their light cannot be seen, IR illuminators are the perfect solution in sensitive areas where light pollution needs to be avoided; areas such as residential neighbourhoods and parks. IR illumination also works well over long distances, with illumination at ranges up to 370m. Therefore in many applications IR illumination is the perfect lighting tool for CCTV, allowing cameras to capture crisp, clear images in black & white, and optimising camera performance.
The law relating to infrared CCTV:
When having infrared CCTV installed you must be sure you abide by the law. Infrared CCTV doesn’t usually cause problems in residential properties so long as your neighbours do not feel you are encroaching on their privacy. So as long as your infrared camera is filming only your property, and not any adjoining properties, you should be well within the Data Protection Act (in UK). However, the rules for commercial properties are different; you will need a license, so consult a CCTV installation company for advice.
On-chip Gain Multiplication Cameras:
On-chip gain multiplication CCD cameras have become popularized for performing low-light security, surveillance and astronomical observation. CCD image detector manufacturers have substantially improved the sensitivity of certain CCD detectors by incorporating an on-chip multiplication gain technology to multiply photon-generated charge above the detector’s noise levels. The multiplication gain takes place after photons have been detected in the device’s active area but before one of the detector’s primary noise sources (e.g. readout noise). In a new multiplication register, electrons are accelerated from pixel-to-pixel by applying high CCD clock voltages. As a result, secondary electrons are generated via an impact-ionization process. Gain can be controlled by varying the clock voltages. Because the signal boost occurs before the charge reaches the on-chip readout amplifier and gets added to the primary noise source, the signal-to-noise ratio for this device is significantly improved over standard CCD cameras and yields low-light imaging performance far superior than traditional CCD cameras.
True day-night camera:
Day and night cameras are cameras that are able to provide video surveillance even at low levels of illumination. A day and night camera displays a full colour image during the daytime but produces monochrome (Black and white) video images at times when the lighting is poor. The camera has a device that is sensitive to the surrounding light conditions and switches the camera between colour and black & white modes automatically. It is designed to increase its light sensitivity in poor lighting conditions and at the same time reduce noise level in the images. True day-night capability is achieved by using an IR cut-filter mechanism (IRCF). Many of the sensors used in today’s security cameras are sensitive to both visible light (380nm~740nm), essentially what the human eye can see, as well as near infrared light (750nm~1100nm), which is emitted from sources such as sunlight, moonlight, halogen fixtures, etc. Unfortunately, to produce accurate colours, most of the IR light needs to be blocked or filtered out. Many cameras do this by using an IR Cut Filter, which sits in front of the sensor like a pair of ‘sunglasses’. With this True Day Night /IRCF feature the camera is equipped to remove these ‘sunglasses’ when the light levels drop below a certain threshold. This allows more of the visible light and available IR light to get to the sensor, dramatically improving low-light performance. Because of the filtering or blocking of the IR light, colour accuracy usually suffers in this mode. Most implementations also remove all colour information, yielding a black and white image that is not only vastly more usable but also cleaner without the chroma noise. The day and night camera will fail if the illumination (Lux) level is too low.
Day & night camera vs. IR camera:
Similar to Day & Night cameras, IR cameras turned to monochrome mode when illumination falls below a certain Lux. An IR camera differs from a Day & Night camera in which an IR camera is able to capture video images in absolute darkness with the help of infrared light source. Day & Night cameras do not have infrared lights built in but uses natural infrared light. Therefore the clarity and quality of image by IR camera is better than Day & Night camera at night. However, some Day & Night cameras have in-built IR light source and therefore can be called as IR camera.
Analog and digital image:
Traditional analogue Images are recorded in some physical form, such as frequency, amplitude or in the case of a photograph, the activation of photo-chemical emulsion.
A digital Image is recorded as a series of binary digits (called bits) – either ones or zeroes. The image is then focused onto an electronic sensor comprising individual light-sensitive elements known as pixels (picture elements). These act as switches to modify an electrical current on or off and the information is processed by a computer. It can then be displayed on a screen, stored in a variety of media or printed out.
Analog to digital conversion at DVR:
When analog video is digitized, the maximum amount of pixels that can be created is based on the number of TV lines available to be digitized. Once the camera captures the images that you want, it will send them through coax cable (or Cat 5 with Baluns) to the DVR. At the DVR, the images are converted from an analog signal into a digital format to be stored on a hard drive. This is the most important part of the chain. The greatest most powerful camera will not be effective if the image is compressed down to nothing by the DVR. The two most popular DVR resolution types are CIF and D1. CIF is defined as 320×240 pixels and D1 is 720×480. As you can tell, D1 is 4 times larger than CIF. That means that the raw analog signal of the camera will be compressed less, giving you better detail.
A digital image is either a digital still photograph or a sequence of digital video which can be viewed on a suitable display medium (including, for example, a computer monitor, a digital television, a CCTV monitor or a print out). A photograph or sequence of video is digital if it is stored in binary format in memory (including, for example, DVDs, CD-ROMs, diskettes, RAM, hard drives, RAID Arrays and tape streamer systems). Digital images can be contrasted with more familiar analog images which are typically captured as a variation in some physical property of the recording medium (including, for example, VHS cassettes or photographic film). The binary nature of digital images gives them certain advantages over analog images. For example, digital images are generally easier to copy perfectly than analog images. Moreover, because a digital image is simply recorded as a set of data in computer memory, it is generally easier to process a digital image than an analog one. Such processing could, for example, include image enhancement or image analysis. It could also include image manipulation. In addition, before a digital image is even stored in memory it is likely to have undergone some processing. Often such processing will involve the compression of the digital image in order to save memory or to make the digital image easier to transmit across a network onto a storage/viewing device. A common example of this compression processing is the DVD. This shows that digital image compression does not necessarily impair image quality.
Pixel as resolution of digital image:
A pixel is generally thought of as the smallest single component of a digital image. It is the smallest controllable element of a picture represented on the screen. The address of a pixel corresponds to its physical coordinates. LCD pixels are manufactured in a two-dimensional grid, and are often represented using dots or squares, but CRT pixels correspond to their timing mechanisms and sweep rates. The more pixels used to represent an image, the closer the result can resemble the original. The number of pixels in an image is sometimes called the resolution, though resolution has a more specific definition. Pixel counts can be expressed as a single number, as in a “three-megapixel” digital camera, which has a nominal three million pixels, or as a pair of numbers, as in a “640 by 480 display”, which has 640 pixels from side to side and 480 from top to bottom (as in a VGA display), and therefore has a total number of 640×480 = 307,200 pixels or 0.3 megapixels. Megapixel IP cameras are now quite commonly delivering 1280 X 1024 pixels. Simply multiply the two numbers to express the resolution in megapixels e.g. 1280 X 1024 = 1.31 megapixels. Two, three and five megapixel cameras have quickly become available, and plainly can deliver much greater image detail than traditional analogue CCTV cameras. There are already IP cameras capable of delivering 16 or even 21 megapixel images. These cameras can deliver images of whole street scenes for recording. There is so much resolution within those images that the recordings can be expanded to reveal facial identity after an event.
The figure above shows increase in image resolution from 0.4 megapixel to 3 megapixel.
Analog resolution in TVL and digital resolution in pixel can be correlated approximately.
520TVL equates to 752 X 582 pixels.
TVL = horizontal pixels X 0.7 i.e. 750 pixels is approximately 525 lines.
The maximum resolution a conventional analog camera can provide after the video signal has been digitized in a digital video recorder or a video encoder is D1, which is 720 X 480 pixels (NTSC) or 720 X 576 pixels (PAL).
Components of CCTV:
A CCTV system consists of three components, cameras, digital video recorders, and monitors. Cameras capture the images, the digital video recorder, usually called a “DVR” records the images and the recorded images are viewed through a video monitor.
Simple CCTV system:
The camera is the element which captures the image and transmits it back to a monitor. The camera needs a lens to be able to focus on the subject. There are a wide variety of lenses to suit different applications. The monitor is the receiver unit which converts the captured image into a picture, allowing you to see it.
Recording the CCTV:
CCTV system set-up featuring camera, lens, DVR and monitor.
As it is not usually practical to have a dedicated person to sit and watch a monitor 24 hours a day, the image captured by the camera needs to be recorded so that it can be viewed later, if necessary. Traditionally, this was done with a time lapse Video Cassette Recorder (VCR) which worked on the same principle as an ordinary domestic video but with the ability to record for a much longer period of time. However, the VCR has now been superseded by the Digital Video Recorder (DVR). The DVR stores the images on to a disk drive in the same way a home computer stores data. A DVR recording lasts longer than a video tape, it does not wear out and the quality of the image is superior. You can also search for an incident easily by time and date.
A multi camera CCTV system:
Most commercial systems today comprise of more than one camera, but you don’t need a monitor and recorder for each camera; several cameras can share one monitor and hard disc recorder or VNA. Equipment is available that will split the monitor into displaying four cameras at once, or a four way sequence unit can be used which allows you to choose which camera you would like to view. Alternatively, the automatic mode will sequence through the four cameras that are connected. However, the most common way of controlling multiple cameras is via a multiplexer. To keep it simple, a multiplexer incorporates the above facilities but also has the ability to individually code mark each image from each camera and because of this, a multiplexer allows all of the cameras on a system to be recorded onto one tape or hard drive unit. The multiplexer then uses these code marks to play back the recorded picture from the camera that you wish to view. Historically multiplexers and recording units were separate pieces of equipment, but recently a number of manufactures have developed units that do both jobs. Multiplexers digitise incoming analogue camera video signals. They then synchronise them by interleaving fields from different cameras and re-converting the digital data back to analogue for recording by an analogue VCR. So internally, a multiplexer already exploits digital technology, but in a rather half-hearted manner. Once digitised, why convert the data back to analogue with a further loss of quality? Digital video recorders already integrate most of the functions of VCRs and multiplexers, with the result that most manufacturers are phasing out multiplexers due to the extremely low demand.
A simple video switcher is designed to direct the signal from one of a series of cameras to a monitor. Most switchers have a control to enable the monitor to sequence automatically through each camera in turn. Some switchers can provide output to two monitors. One monitor can be locked on to a specific camera while the other sequences. Matrix switchers are now becoming common place in the market due to the development of microprocessor technology. This type of switcher can process the signals from a large number of cameras to many monitors. There can also be many control positions, each of which can call up any of the cameras. In a railway system for instance, it is possible to have two hundred stations each with twenty cameras. Each station would have individual control of its own cameras to sequence or select. All the stations would be connected back to a central location that could control all four thousand cameras. The central control could then be divided into say ten regions each with a control and bank of monitors for its own group of cameras.
Multiple Screen Displays:
Any system that combines more than one video signal is technically a multiplexer. These days it is customary to refer to multiplexers as equipment that can simultaneously combine eight or more signals, otherwise they are known as screen splitters or quad splitters. There will be many occasions when it will be advantageous to display more than one camera on the monitor at once. To display or record more than one picture at a time it is necessary on most systems to convert the analogue signal to a digital form. This is known as analogue to digital conversion. After processing, the signal then has to be converted back to analogue form to be displayed on a monitor. This process introduces the possibility of degradation to the original picture. Definition can be lost through the complicated conversion processes and noise can be added to the signal. Also, the final quality is dependent on the resolution in terms of the number of pixels comprising the digital information.
Picture in Picture:
This is a simple system by which one scene can be inserted in another. The camera outputs are connected to a controller that allows one camera to be designated as the main picture. The other camera is designated as the inserted picture. The inserted picture may be positioned and sized anywhere on the screen.
This is similar to a picture in picture inserter except that both camera scenes can be adjusted to compose the most useful combination. A screen splitter refers to a combination of two cameras. The split can be arranged either horizontally or vertically. The degree of overlap of either camera can also be adjusted. Screen splitters also require the cameras to be synchronised.
Quad Screen Splitters :
As the name implies, this system allows the presentation of four cameras on the one screen. The majority of quad splitters now incorporate digital image processing. This means that it is not necessary to synchronise the cameras and the picture is digitally compressed to a quarter of its size. The four images are then displayed on a single screen. Note that each picture will only be 25% of the screen resolution. There are many features that may be available with quad screen splitters and it is essential to check with manufacturers’ literature for particular models. As always, the more features it provides the more expensive a unit is likely to be. It is possible to spend more than necessary if poor selection of a piece of equipment includes more features than are required. Another factor to check out is the resolution of the displayed pictures.
Analog & digital recording:
The era of analog closed circuit television (CCTV) systems is coming to an end. The multiplexer, video cassette recorder, switcher and all of those T-160 tapes are being replaced with computers, embedded processors, capture cards, encoders, decoders, codecs, redundant array of disks (RAID), network video recorders and 10/100/gigabyte/optical networks, and that’s only the beginning of the list. With an analog system, the term “horizontal lines of resolution” dictated what the video quality and recording quality was.
Types of digital recording:
There are two types of digital recording: direct digital and encoded digital. It is important to recognize the differences between the two. Direct digital is much like a digital photographic camera, which captures pictures directly. As a result, the direct digital image (also called a frame) has a great deal of information. Some of these cameras are described as mega-pixel cameras, because the information (picture) captured can be very detailed. The larger the number of mega-pixels, the greater the detail and commensurate file size of the picture. These pictures are 100 percent digital. They are not scanned or converted and can be captured in a variety of formats, including JPEG. The second type of digital recording — encoded digital — involves encoding or capturing analog frames of video and converting them to digital pictures. Although the term “frame” is used in discussions of both digital and analog video, it has somewhat different meanings in each case. As it relates to analog, a frame refers to a single picture that interlaces two fields, which are painted onto an analog monitor as a single frame. By comparison, one frame in the digital world equates to a single photo or digital picture file. Digital recording captures the scene or the analog video picture-by-picture or frame-by-frame. The individual frames, created by either analog or digital, create the appearance of motion, but in reality the movement is just a grouping of images presented very quickly. The biggest difference between encoded and direct digital is the amount of information captured. The information captured by a digital camera is only limited to the number of pixels that can be captured in a field of view. As with digital photographic cameras, an eight mega-pixel unit captures less information than a 10 mega-pixel camera. By contrast, when analog video is encoded to a digital file, the only information available is information that has already been captured. A 400-line camera that is encoded to digital still is limited to the 400 lines that were originally captured. Although these horizontal lines of resolution are converted to digital, there is no magic process that will add information to an analog frame/field that was previously captured. As a result, the video captured cannot be enhanced — an important distinction to be aware of when it comes to direct and encoded digital CCTV. The data from digital files is large, which is why data storage and transmission are big concerns. Digital video utilizes proprietary conversion methods called codecs to strip information from the files, thereby reducing their size. This information can include image size, colors, grayscale, frames-per-second, etc.
Analog and Digital/ IP (internet protocol) CCTV:
1. Analog CCTV is a method of recording analog video and analog audio using VHS (video home system) magnetic tape on a VCR (video cassette recorder) that can play back the recording.
2. Digital CCTV uses computer technology to digitize CCTV camera images and compress them. CCTV can be stored on a PC-based system or a dedicated digital video recorder (DVR) to play back the recording. A more advanced form of CCTV, utilizing digital video recorders (DVRs), provides recording for possibly many years, with a variety of quality and performance options and extra features (such as motion detection and email alerts). More recently, decentralized IP cameras, some equipped with megapixel sensors, support recording directly to network-attached storage devices, or internal flash for completely stand-alone operation.
The figure below shows difference in image quality vis-à-vis analog CCTV and IP CCTV:
Analog CCTV systems use one of two main conduits to transmit audio-visual information. The first, and most common, is a wired configuration. The second uses a wireless transmitter to connect to a receiver. Wired CCTV installations run a cable or wire between the camera and the monitor. The image data is usually transmitted over a coaxial cable. The audio is usually transmitted over a simple copper wire or wires. The signal transmitted over these wires and cables is then fed in to a monitor or a set of monitors if the image needs to be visible in different locations. A multiplexer can be used to display feeds from multiple cameras on a single monitor. Each camera’s picture would take up a pre-set amount of space on the monitor. Analog CCTV cameras can also be routed to an image capture board on a computer to allow the audio-visual information to be viewed on a computer monitor. Wireless CCTV installations are similar to wired. The difference is that a radio transmitter is attached to the camera. A radio receiver is then attached to the input on the monitor system or computer. Wireless systems are useful in a couple of situations. The first is when the distance between the camera and the monitor is too far to be practical for a cable run. Wireless CCTV is also good when cables aren’t practical because of aesthetic reasons.
Analog CCTV System Design:
In the traditional analog CCTV application, security cameras capture an analog video signal and transfer that signal over coax cable to the Digital Video Recorder (DVR). Each camera may be powered by plugging in the power supply right at the camera or by using RG59 Siamese cable which bundles the video and the power cables. The DVR converts the analog signal to digital, compresses it, and then stores it on a hard drive for later retrieval. Intelligence is built into the DVR to handle such things as scheduling, motion detection, and digital zoom. Monitors for viewing the video are connected to the DVR, or it can be set up to publish over an internal network for viewing on PCs. The DVR can also be set up to broadcast over the Internet and can add password protection and other features. When broadcasting over the Internet, the video for all of the cameras is transmitted as one stream (one IP address). Therefore, it is very efficient.
The advantages of standard definition (SD) CCTV:
You may see standard CCTV referred to as SD (standard definition), traditional, conventional or analog (or analogue) CCTV or digital output SD CCTV. All these terms usually refer to the same CCTV technology.
What are the advantages with a standard CCTV system?
1. Analog CCTV systems are often less expensive overall:
Analog CCTV products are at this point in time still cheaper than their IP counterparts – NVRs can be twice as expensive as a DVR for example. The installation of an analog surveillance system can also be less expensive because they are quicker to install with minimal network set-up and configuration. However in some situations a single IP camera can be installed in the place of a number of standard CCTV cameras so I recommend looking at both options before making a final decision.
2. Analog CCTV systems are easier to maintain:
Overall standard CCTV security systems need little maintenance once installed. I recommend a basic check once a week to confirm all cameras are recording and footage can be retrieved from the DVR. Because an analog system is not attached to the business or home network it won’t be at the mercy of network issues. Large file sizes, limitations to the bandwidth, viruses or too many devices trying to use the network (congestion) are just some of the challenges facing the installation and ongoing maintenance of an IP system.
3. Analog CCTV cameras can perform better in some environments:
Depending on the environment an analog security camera may perform better than an IP camera in the same position. Situations where this may occur include:
•Low light: The CMOS image sensors normally used in IP cameras deliver great HD resolution but do not handle low light very well. Some IP cameras will produce a grainy picture at low light (which also uses up bandwidth and storage space because it is interpreted as motion). Many analog cameras use a CCD image sensor which has much better low light performance.
•Darkness: Most analog surveillance camera include in-built IR (infrared) that allows the camera to record images even in complete darkness. While IP cameras will record down to a very low level of light if they need to record in zero lux, separate IR illuminators will need to be installed.
•Fluorescent lighting: Fluorescent lighting is used in many indoor spaces and it can create problems, particularly for IP cameras. The frequency of the fluorescent lighting and the power source can clash which creates a constant flicker on the live and recorded video image. Accurate colour information may also be affected. Note that this problem can also affect some standard analogue CCTV cameras with CCD image sensors.
There are already several camcorders on the market that produce a digital output instead of an analogue video signal. These record onto a miniature DAT (Digital AudioTape) in digital form or download straight to codecs. The playback can be either via a digital to analogue converter in to a conventional monitor, or direct by RGB input to a computer monitor. The direct input into a computer monitor will provide a significant improvement in resolution and colour rendering. The recording capability for CCTV is still limited by the current problems of compression and storage capacity, but this is advancing rapidly and soon will not be the main problem. These cameras do not require a video capture card because they work using a digital signal which can be saved directly to a computer. The signal is compressed 5:1, but DVD quality can be achieved with more compression (MPEG-2 is standard for DVD-video, and has a higher compression ratio than 5:1, with a slightly lower video quality than 5:1 at best, and is adjustable for the amount of space to be taken up versus the quality of picture needed or desired). The highest picture quality of DVD is only slightly lower than the quality of basic 5:1-compression DV.
Talking CCTV is a CCTV surveillance camera that is equipped with a speaker to allow an operator to speak to the people at the CCTV-monitored site. Messages are typically designed for each specific location. Research has shown that although people will only obey a written notice to leave in 7% of cases, they will obey an audible command 92% of the time.
Signal to noise ratio (SNR):
The arch enemy of picture clarity on a monitor is noise; this is electronic noise that is present to some extent in all video signals. Noise manifests itself as snow or graininess over the whole picture on the monitor. There are several sources of noise; poor circuit design, heat, over-amplification, external influences, automatic gain control, transmission systems such as microwave, infrared etc. The important factor that determines the tolerance of noise is the amount of noise in the video signal, the signal to noise ratio. Note that every time that a video signal is processed in any way, noise is introduced. The only real way to reduce noise lies in correct system design, selection of equipment and transmission systems. Once it is there, it won’t go away and can only get worse.
Automatic gain control (AGC):
When the light falling on to an imaging device reduces to a certain level, it is insufficient to create a full level video signal. AGC acts to increase the amount of amplification in these conditions to bring the signal up to the required level. As well as amplifying the video signal, additional noise can be introduced, and the signal to noise ratio reduced. The result is frequently a very much degraded signal and poor picture on the monitor.
CCTV video retention period:
Under normal circumstances, a retention period of seven days is considered to be a sufficient and reasonable time for the keeping of CCTV camera recordings. After the lapse of this period, images are automatically deleted or overwritten by new images. However, this depends on various technical characteristics of the system and other factors.
CCTV installations can also be digital. Digital CCTV often uses Internet Protocol (IP) cameras although digital CCTV can be without IP camera using analog/digital DSP camera, DVR and monitors. An IP camera is a camera that contains the camera and hardware to convert the audio and video signals to a stream of packets that can then be transmitted over a local area network (LAN), wide area network, (WAN) or even over the internet. Digital CCTV has many advantages over analog. First, it can use existing wired or wireless internet, including Wi-Fi. Because of this, it isn’t limited by distance. A CCTV camera can be set up in one city and have its signal transmitted easily to another city. Another advantage of digital CCTV is that a series of cameras can be routed to a wireless hub, thus minimizing the amount of cabling required for a complex installation.
Conventional analog vs. digital IP camera:
An analog surveillance camera begins with a CCD sensor and then digitizes the image for processing. But before it can transmit the video, it needs to convert it back to analog so it can be received by an analog device, such as a video monitor or recorder (VCR). Unlike IP cameras, analog have no built-in web servers or encoders and require no technical maintenance. These functions are implemented in the recording and/or control equipment. What is commonly known as an IP camera is a camera that digitizes and processes analog images, encodes them internally, and then transmits the video information digitally over an Ethernet connection to a computer or similar device. An IP camera can have either a CMOS or a CCD sensor, and is available in the same styles as traditional surveillance cameras such as Pan/Tilt/Zoom, domes, bullets, box, infrared, covert, and wireless. For an IP camera the image is then compressed internally (encoded) and transmitted via an IP protocol (Ethernet) and is either stored in the camera or on a network video recorder (NVR). For an analog camera, the image is then converted back to analog by a digital-to-analog converter so the image can be transmitted to a video monitor, to VCR or a digital video recorder (DVR), where the image is encoded and stored. DVR reconverts analog signals into digital signals using DAC. At this point, it seems the difference between the two types of cameras is negligible. Primarily, the difference is where the video is compressed and what components it utilizes.
IP camera (network camera):
An Internet protocol camera, or IP camera, is a type of digital video camera commonly employed for surveillance, and which unlike analog closed circuit television cameras can send and receive data via a computer network and the Internet. Although most cameras that do this are webcams, the term “IP camera” or “netcam” is usually applied only to those used for surveillance. The first centralized IP camera was Axis Neteye 200, released in 1996 by Axis Communications. Analog closed circuit television uses established broadcast television formats (e.g. Common Intermediate Format (CIF), NTSC, PAL, and SECAM). Generally speaking, each make of IP camera will differ in its features and functions, video encoding (compression) schemes, available network protocols, and the API to be used by video management software. In order to address issues of standardization of IP video surveillance, two industry groups were formed in 2008: the Open Network Video Interface Forum (ONVIF) and the Physical Security Interoperability Alliance (PSIA). While the PSIA was founded by 20 member companies including Honeywell, GE Security and Cisco, and ONVIF was founded by Axis Communications, Bosch and Sony, each group now has numerous members. As of January 2009, each group had released version 1.0 of their specification.
There are two kinds of IP cameras:
•Centralized IP cameras, which require a central Network Video Recorder (NVR) to handle the recording, video and alarm management.
•Decentralized IP cameras, which do not require a central Network Video Recorder (NVR), as the cameras have recording function built-in and can thus record directly to any standard storage media, such as SD cards, NAS (network attached storage) or a PC/Server.
IP cameras or network cameras have an embedded video server having an IP address, capable of streaming the video (and sometimes, even audio). Because network cameras are embedded devices, and do not need to output an analogue signal, resolutions higher than closed-circuit television ‘CCTV’ analogue cameras are possible. A typical analogue CCTV camera has a PAL (768×576 pixels) or NTSC (720×480 pixels), whereas network cameras may have VGA (640×480 pixels), SVGA (800×600 pixels) or quad-VGA (1280×960 pixels, also referred to as “megapixel”) resolutions. An analogue or digital camera connected to a video server acts as a network camera, but the image size is restricted to that of the video standard of the camera. Network cameras can be used for very cheap surveillance solutions (requiring one network camera, some Ethernet cabling, and one PC), or to replace entire CCTV installations (cameras become network cameras, tape recorders become DVRs, and CCTV monitors become computers with TFT screens and specialised software. Digital video manufacturers claim that turning CCTV installations into digital video installations is inherently better). There continues to be much debate over the merits and price-for-performance of Network cameras as compared to analog cameras. Many in the CCTV industry claim that many analog cameras can outperform network cameras at a lower price.
IP cameras are typically equipped with an embedded web server and can be accessed and controlled over any IP network such as a WAN, LAN, Intranet, or Internet. By utilizing a standard web browser or client software users can view an IP camera’s video output from any local or remote location. IP cameras combine the capabilities of a camera with some PC functionality, do not require a direct connection to a PC to operate, and can be placed anywhere within a network. Just like any other PC on the network, an IP camera is a “network appliance”. It has its own IP address, connects directly to a wired or wireless network and requires maintenance. With the advent of IP or Network cameras, the method of installing CCTV system changes dramatically. These IP cameras are plug and play devices as far as the network is concerned. They are easy to integrate into corporate LANs or WANs. There is no need for multiplexing, coaxial cabling, balun adapters, CCTV keyboards, analog VCRs and tapes. An IP camera takes the video, compresses it and sends it over the LAN to a network attached storage (NAS) device, a storage area network (SAN) or a video server. An IP camera is always streaming video across the network, and therefore, is always using bandwidth. Hence a separate or segmented LAN is recommended to avoid bottleneck issues on the main corporate network. However, some IP cameras now incorporate both server and DVR functions and this helps to limit some of the bandwidth impact. The connection to the LAN is via 10/100/1000 Mbps Ethernet.
Power over Ethernet (POE):
Power over Ethernet or PoE describes any of several standardized or ad-hoc systems which pass electrical power along with data on Ethernet cabling. This allows a single cable to provide both data connection and electrical power to devices such as wireless access points or IP cameras. Most network cameras can be fed with their power via the same network cable that will carry the video data back to the network. Recent developments now allow for higher power devices such as pan, tilt, zoom cameras and lights to be fed via POE. Even external camera housing heaters can now be fed via POE. Traditional analogue CCTV cameras would normally require an electrician to provide an adjacent mains supply, or at the very least to be fed power separately via a second low-voltage supply cable.
Transmission of video along telephone lines or fiber optic cable requires an analogue to digital converter (ADC) to be incorporated in the transmitter and the reverse digital to analogue converter (DAC) at the receiving end. Using a direct digital output from the IP camera will render the ADC unnecessary, thus saving cost. When equipment is available that can accept a digital signal then the DAC will not be required providing further savings. It will no longer to use coaxial cable with all its problems of connectors and limited range. Instead, simple twisted pair cables can be used with greatly improved distances and quality. Multiplexers need to convert the analogue signal to a digital signal to hold in the frame store; again, this will be unnecessary. Every time a conversion from one form of signal to another is rendered unnecessary, there will be an improvement in resolution and picture quality.
IP / Network CCTV System Design:
In the IP world, each network camera captures an analog image but immediately converts it to digital inside the camera. Some digital processing can happen right at the camera, such as compression and motion detection. The digital video stream is then broadcast over the local area network (LAN) using Ethernet (CAT5 or CAT6) cable. Power is supplied to the cameras through the ethernet cable via Power-Over-Ethernet (POE) adapters built into the cameras and at the (POE enabled) switch. The ethernet cable for each camera is plugged into the switch which feeds into the network hub. As with all network devices, some set-up needs to be done for each network camera to set up its IP address and other identifying attributes. A Network Video Recorder (NVR) performs the same function as its DVR cousin in the analog world. It captures each camera’s signal, compresses, and records it. The main difference is that the video feeds are digital (and much higher resolution) and not analog. Software built into the NVR provides features such as intelligent search and zoom, etc. The NVR combines the video streams from the cameras and handles the broadcast over the LAN and internet for local and remote viewing.
How IP CCTV system works:
Utilising existing IP networks:
Most organisations now have IP-based computer networks with connections to the Internet. IP cameras can simply be added to such networks, extending its functionality to include video.
IP cameras and recorded video footage can be viewed using computers on the local network, or remotely via the Internet. User access can be limited by using passwords and IP filtering, and video can be encrypted for additional security.
Existing analogue CCTV cameras do not have to be wasted. The analogue output of CCTV cameras can be digitised using video encoders, enabling the video signals to be sent over IP networks.
Using video management software (VMS), video can be recorded and stored on computers that are part of the network. The footage can be viewed by authorised users, either locally or remotely. As an alternative to using video management software, recording and video management can also be done using a dedicated network video recorder (NVR). This is added to the network in the same way a PC or server would be added.
Existing analogue monitoring equipment does not have to be discarded either. If video monitoring is required on an existing CCTV monitors, video decoders can be used to convert IP signals back to analogue.
Potential advantages of IP CCTV system:
•Two-way audio via a single network cable allows users to communicate with what they are seeing (e.g. gas station clerk assisting a customer on how to use the pay pumps)
•Flexibility: IP cameras can be moved around anywhere on a network (wireless).
•Distributed intelligence: with IP cameras, video analytics can be placed in the camera itself allowing ability in analytics solutions.
•Transmission of commands for PTZ (pan, tilt, zoom) cameras via a single network.
•Encryption & authentication: IP cameras offer secure data transmission through encryption and authentication methods such as WPA, WPA2, TKIP, AES.
•Remote accessibility: live video from selected cameras can be viewed from any computer, anywhere, and also from many mobile smart-phones and other devices. Remote accessibility also prevents police officers from confiscating video and audio evidence that you can use against them.
•IP cameras are able to function on a wireless network.
•PoE – Power over Ethernet: Modern IP cameras have the ability to operate without a power supply. They can work with the PoE-protocol.
•IP camera communication signals are not just electronic voltage; it is numerically decoded as bits and bytes with security features and TCP/IP protocol.
Potential disadvantages of IP CCTV system:
•Higher initial cost per camera, except where cheaper webcams are used.
•High network bandwidth requirements: a typical CCTV camera with resolution of 640×480 pixels and 10 frames per second (10 frame/s) in MJPEG mode requires about 3 Mbit/s.
•As with a CCTV/DVR system, if the video is transmitted over the public Internet rather than a private IP LAN, the system becomes open to a wider audience of hackers and hoaxers. Criminals can hack into a CCTV system to observe security measures and personnel, thereby facilitating criminal acts and rendering the surveillance counterproductive.
Comparison of analog CCTV system and IP CCTV system:
Analog continues to dominate the security market representing 80% to 90% of the market (depending upon whose numbers you subscribe to.) More importantly, these figures do not take into account the significance of tens of millions of analog cameras, DVRs and the legacy infrastructure currently in service. Customers with substantial investments in analog infrastructure are interested in getting a longer useful life out of their current systems, especially in these trying economic times. By comparison, IP based CCTV solutions are more costly than analog systems of comparable quality, more complex to install and require extensive supplementary management. The issue is for decades analog video systems as well as access control and alarm systems were installed and you forgot them; little “technical” maintenance was required. The customer was not interested in hiring expensive professional staff to maintain esoteric systems. Where the incentive for change to IP cameras is greatest is in applications that are not supported well by analog such as megapixel recording, analytics on the edge and large scale wireless transmission. Of the IP cameras sold, high megapixel cameras represent a fraction of 1% of the overall market. From a “future-proofing” perspective, hybrid DVRs, which accommodate both analog and IP cameras, offer expandability without limitation to transmission method.
Analog camera systems transmit over coax, not the LAN, so their bandwidth is not much of an issue. The only use of the LAN in analog systems is for the DVR to broadcast video data over the network to local desktop users or to the internet. DVRs tend to broadcast video very efficiently and will only use bandwidth if people are currently viewing the cameras. In IP camera systems on the other hand, each IP camera uses the LAN to broadcast their signal to the NVR so bandwidth can be a big issue. As a general rule, an IP camera using full CIF (352 x 288) resolution, 30 frames per second (30 fps), and MPEG4 compression will require about 720K bits per second (720Kbps). Therefore, if we put 100 IP cameras running CIF on a network, we would use about 72Mbps of bandwidth. This number will double if audio is also transmitted. However, to make bandwidth matters worse for IP – most of the newest IP cameras are coming out with ‘megapixel’ resolution. This is wonderful from the standpoint of how much clarity and field-of-view can be captured, but it comes at a huge price to bandwidth. A single 2-megapixel IP camera, running 30 fps with MPEG4 compression will use a whopping 6.5Mbps of bandwidth. It should come as no surprise then that some companies have gone so far as to create an entirely separate IP network just to run their camera system.
Advantages of IP CCTV over conventional CCTV:
The Surveillance Market globally has ‘tipped’ from traditional CCTV to IP cameras. In the last year, for new projects in the US and Europe, it has become clear that IP camera sales are outpacing analogue sales. Among enterprise projects, IP’s predominance is almost shocking with more than 75% of new projects going with IP. There are some benefits and reasons to choose IP Surveillance over traditional CCTV.
1. Resolution: An analogue camera of 540TVL equates to about 0.4 MP, whereas a standard IP camera of 2 MP, can give over 5 times that resolution. With some IP cameras ranging up to 10MP, it’s easy to see how the technology can cut down on the overall number of cameras required. A typical example would be replacing PTZs on a garage forecourt with one IP/Megapixel camera.
2. Remote Access: You can login into a secure server remotely, using a web-based interface, to view real-time footage on PCs or Macs, as well as mobile devices such as the iPhone, iPad, and Android. Programs such as TeamViewer also allow for remote support and end-user training.
3. Analytics: The dramatic improvements in hardware have been matched by powerful Analytics Software. Video Management Systems (VMS) can be combined with other software to allow for applications such as license plate recognition, people counting, and motion detection.
4. Power: IP cameras utilize Ethernet cables which allow for Power over Ethernet (PoE), meaning only one cable per camera is required, to carry both power and data. Furthermore, if re-wiring would prove too costly, it is possible to install a device such as Veracity’s Highwire which can allow data and PoE over coax cable.
5. Hybrid: High end Network Video Recorders (NVRs), such as the Minotaur Server, allow existing CCTV cameras to be incorporated into the IP system. This can significantly reduce the initial costs, and allow a phased approach towards a complete IP Surveillance solution.
6. Scalability: Utilizing edge processing, and individual camera licensing, it is possible to scale from a single camera up to thousands.
7. Redundancy: It is possible to record simultaneously to a Network Video Recorder (NVR), and a SD card installed locally on the IP camera. This offers an additional safety net to recover footage in the event of damage/corruption to data on the main NVR.
8. Lossless Playback: Footage can be reviewed with multiple zoom on playback, even on fixed lens cameras, with no degradation of the image. This alleviates a common problem with analogue systems, where high levels of compression can often leave the image unreadable.
9. Open Standards: Video Management Systems (VMS), such as ExacqVision, are based on the global standards defined by ONVIF. This allows for interoperability of cameras from various manufacturers, across a single network.
10. Wireless: If it’s possible to get a line-of-sight between the camera and the server’s location, it is possible to reduce cabling costs by transmitting the data wirelessly, using a product such as the Ubiquiti NanoStation.
CCTV signals are sent with DC current, which loses power as it moves through the cable. Coax is designed to carry high-frequency signals, and to protect those signals against electromagnetic interference (EMI) from external sources. It’s a fairly common type of shielded data transmission cable, which is made up of two conductors that are coaxially oriented (hence the name), but separated by a layer of insulation. CCTV video signals are commonly transmitted using coaxial cable. Coaxial cable is designed to transmit the complete video frequency range with minimum distortion or attenuation, making it an excellent choice for CCTV. Coaxial cables are also available in different RG types. RG stands for Radio Guide and is a term used when sending Radio Frequency (RF) signals down a coaxial cable. An RG 59 cable is the most commonly used coax because it is smaller in diameter and easy to work with. Check that the cable is properly sized for the distance between your camera and your receiver. For instance, RG59 cable is frequently used in CCTV installations, but for runs longer than 1,000 feet you need RG6 or RG11 cable to avoid too much signal loss.
Can analog cables be used in digital applications?
Yes, up to a point; but the looser tolerances of older analog cable designs will limit their run lengths, at least when used in high-bandwidth applications like SDI video.
Can digital cables be used in analog applications? Yes, absolutely; the same tight tolerances which make digital cables appropriate for digital applications make them superb for analog applications. One may not “need” the improvement, but it will never hurt, and can help. SDI coax, like Belden 1694A, costs very little more than (and in many cases less than) traditional analog coax designs, and will outperform it on every measure of analog cable performance.
Why CATV (cable TV) cable does not work on CCTV system:
When pricing out the cable to use to build a Closed Circuit Television System (CCTV) to connect cameras to a central monitor location, many system operators are seduced by the much cheaper price of CATV cable. After all the specs quoted about the transmission at, say 300 MHz look really good, so after all that cable should work really well for video transmission, right? No, wrong!! While the loss of the CATV type of coaxial cable is quite low at very high frequencies such as 300 MHz, the loss at video frequencies is quite high; therefore picture content may be quite dim by comparison to cable intended for use for CCTV purposes. The reason for this difference at video frequencies (D.C. to 5MHz) is that the center conductor of the CATV type of coaxial cable is made of copper plated steel, not pure the oxygen-free copper needed for low loss at video frequencies. Steel is lower in price than copper, thus the lower price of the CATV cable. As we all know, steel has a much higher resistance (thus loss) than pure copper, therefore the CATV type of cable is not at all suitable for CCTV purposes. The reason that the CATV systems can use the steel center conductor cable is that at the higher frequencies used by that industry, the copper plating is thick enough so that none of the RF energy penetrates into the steel core and thus induce loss. It is the skin effect that makes this possible. In this case the CATV Industry only uses the steel to help support the cable between the house and the telephone pole.
Wireless security cameras are closed-circuit television (CCTV) cameras that transmit a video and audio signal to a wireless receiver through a radio band. Many wireless security cameras require at least one cable or wire for power; “wireless” refers to the transmission of video/audio. However, some wireless security cameras are battery-powered, making the cameras truly wireless from top to bottom. Wireless cameras are proving very popular among modern security consumers due to their low installation costs (there is no need to run expensive video extension cables) and flexible mounting options; wireless cameras can be mounted/installed in locations previously unavailable to standard wired cameras. In addition to the ease of use and convenience of access, wireless security camera allows users to leverage broadband wireless internet to provide seamless video streaming over-internet. Wireless security cameras function best when there is a clear line of sight between the camera(s) and the receiver. Outdoors, and with clear line of sight, digital wireless cameras typically have a range between 250 to 450 feet. Indoors, the range can be limited to 100 to 150 feet. Cubical walls, drywall, glass, and windows generally do not degrade wireless signal strength. Brick, concrete floors, and walls degrade signal strength. Trees that are in the line of sight of the wireless camera and receiver may impact signal strength. The signal range also depends on whether there are competing signals using the same frequency as the camera. For example, signals from cordless phones or routers may affect signal strength. When this happens, the camera image may freeze, or appear “choppy”. Typical solution involves locking the channel that wireless router operates on.
Analog wireless camera:
Analog wireless is the transmission of audio and video signals using radio frequencies. Typically, analog wireless has a transmission range of around 300 feet (91 meters) in open space; walls, doors, and furniture will reduce this range.
Digital wireless cameras:
Digital wireless is the transmission of audio and video analog signals encoded as digital packets over high-bandwidth radio frequencies.
Wireless IP CCTV System Design:
IP Wireless security camera system design is very similar to standard IP camera system design except for the addition of wireless access points inserted between the home network switch and the cameras. This allows you to place cameras up to 1.5 miles (plus up to 328 feet of Ethernet cable) away from your local area network (LAN).
Advantages of wireless CCTV:
1. Easy and inexpensive installation and setup – It takes a long time to set up a traditional CCTV but it takes just 3-4 hours to install a wireless CCTV. Wired cameras have to be mounted on walls. You need to fix a wall mount first and then mount the camera. There is no need or digging and drilling to install the cables. These steps are not needed for a wireless CCTV because it can be easily connected to an IP camera or other IP hardware like DVRs.
2. No wires and no tangles – These days there are too much wires and cables all over a home. There are wires for TV, computers and all other electric gadgets. Wires all over a room can affect the looks of a room. Moreover, the wires and cables get tangled with each other. Dust keeps on accumulating on them. It is difficult to remove the dust from these wires. No wires’ is a big plus for wireless CCTV.
3. Mobility -You can move your IP cameras to any place you wish. You need not worry about reinstalling the camera. It is mobile and can be carried anywhere you like. You can change the area of access from time to time.
4. Flexibility – Wired cameras cannot be installed in all places that you want. Wireless cameras can be installed even in high places because you need no switch boards and other outlets.
5. Compact size – IP cameras are compact in size. They are easy to carry and good to look at. They can be concealed in a corner or in shelves,
6. Reduced maintenance – Cable maintenance is one of the important costs incurred in wired CCTV. You can save the cost and time spent for cable maintenance. The line leasing costs are also saved.
7. Retrieval of videos – It is easy to retrieve the videos stored from IP cameras. You have scope of remote access to the data with smart phones and iPads. You can have a live footage on your phone.
8. Coverage – The coverage of IP cameras in wireless CCTV vary depending upon the price and model. There are cameras that can receive signals from a distance of up to 10 miles or more. You have the option of choosing a camera to suit your needs and your budget.
9. Security – Wireless CCTV is the best option for motion detection. It records every single movement and when you have live footage, you are assured of more security.
Disadvantages of Wireless CCTV:
1. Disruption of signals – This is the major con. Wireless IP cameras operate on one specific frequency. The chances of the signals getting disrupted are high if there are other networks, internet and microwaves.
2. Risk of hacking – If the camera is not secured properly, you have to face the risk of hacking.
3. Professional help – If there is any problem, you need the help of a professional technician to fix it. You can’t fix it yourselves.
4. Quality of images – The video may not be of high quality because of disruptions.
Experts prefer to install wired security camera systems. Here’s why:
•Wired security camera systems provide high-def resolution. With high-definition images, you have the ability to read license plate tags, do facial recognition and zoom in up to 1000x, if necessary. These capabilities are not available with images provided by wireless security camera systems.
•Wired security camera systems are more secure. Most people do not realize that wireless systems are “hackable” with the right equipment. That means a techie thief or voyeur could look into your home or property and invade your privacy. With a wired security camera system, though, your privacy is protected.
•Wired security camera systems are more reliable. Wireless camera images often contain “snow” due to poor signal strength or electronic interference. Also, a wireless system requires numerous components such as routers, broadcasters, and receivers — any one of which can fail and render your system inoperable. In addition, wireless signals do not penetrate building structures made of concrete, brick or stucco.
VCR, DVR and NVR:
There are two main ways to record video images that CCTV cameras capture. They are analog tape and digital video recorders. Most analog video recorders use VCR tapes or standard VCRs to record the images or special security time-lapse VCRs to record images for a longer period of time.
Video cassette recorder (VCR):
A tape recorder such as a security-time lapse VCR can record CCTV camera images in either black and white or color for all the way up to 960 hours, which is 40 complete days. The determining factor is how many frames per second users intend to record and how many cameras are hooked up to the VCR for recording. For instance, if a user records 30 frames per second (real time video), he/she will only be able to get a few hours of video captured on the recorder. If users record one frame per second or less, they can record for dozens of hours before the video tape is full. VCRs are very practical, very reliable, and extremely affordable. Expect to pay only a few hundred dollars for a security VCR.
Digital Video Recorder (DVR):
There are two types of DVRs (Digital Video Recorders). They are either stand alone devices or hard drives that are connected to a computer system. DVRs work similar to VCRs, but the images they capture from the CCTV camera is digital. The amount of digital images captured on a DVR is determined by a few factors including the frames per second recorded, the amount of cameras hooked up to the DVR device, the resolution that the DVR saves the images at, and the video compression used (e.g. MPEG4). For a common set up, where 4 cameras are shooting at 30 fps and an image resolution of 320 X 240 is being used, each camera only records when motion is on, and MPEG4 compression is used, users should be able fill up a 20 to 25 GB hard drive in about 80 hours.
What is the difference between a PC-based DVR and an Embedded DVR (stand alone DVR)?
A PC-based digital video recorder is basically a personal computer that has been modified with hardware and software to work as a DVR. A PC-based system looks a lot like a tower computer unit. Similar to your PC, the system’s hard drive, LAN board, motherboard, and video card are all located in the computer tower. There is also a DVD-writer to burn your security video images to and a card that records security images. An embedded digital video recorder is a video recording machine that has been manufactured specifically to record video input from CCTV cameras. A stand alone system (embedded DVR) looks a lot like a DVD player or an old VCR with all their components encased in one cabinet. This includes the CPU, IC chips, and power supplies. Everything you need to have to operate the unit is located in one cabinet. The Stand alone DVR works with very little or no help from the computer. It is a plug and play meaning that installation is very easy and recording can start as soon as the device is installed. Stand alone DVRs can support 4-16 cameras, and a television screen can be added for viewing live pictures. Stand alone DVRs provide all the features that come with computer based DVR systems including network support options that allow you to share the recorded data. The motion of the camera can be controlled based on motion and playback and search option are also available. Stand alone DVRs are as their name implies not connected to a network. However, they can be connected to the internet so that an authorized person can view the images collected on the DVRs in real time over the internet. With such an internet connection, authorized personnel can, as well, locate and view images stored on the DVR.
Most CCTV systems may record and store digital video and images to a digital video recorder (DVR) or, in the case of IP cameras, directly to a server, either on-site or offsite. There is a cost in the retention of the images produced by CCTV systems. The amount and quality of data stored on storage media is subject to compression ratios, images stored per second, image size and is affected by the retention period of the videos or images. Digital storage is the most effective and efficient method of video recording and archiving. In digital recording, each field is divided in to an array of individual points or pixels. A single frame of monochrome video needs about 450KB (Kilobytes) of space for storage and a single frame of color needs about 650KB. This is the uncompressed size. Consequently to store the same number of images as a videotape, a total storage capacity of about 280GB (Gigabytes) would be needed for one camera. This is considerably larger than hard discs and other media generally available and would also be tremendously expensive. Consequently some means of compression is required to reduce the amount of space required without adversely affecting picture quality. This has led to the introduction of digital video recorders (DVRs), which allow video to be recorded in higher resolutions than VCRs and eliminated video tapes, which in turn eradicated the need to physically change the tape. The DVR converts the analog video to digital format and compresses it before storing it on its hard drive. Alternatively, the compressed digital video can be sent over the LAN. DVRs store images in a variety of proprietary file formats. Recordings may be retained for a preset amount of time and then automatically archived, overwritten or deleted, the period being determined by the organisation that generated them. Unlike analog recording mediums, long-term digital storage media do not allow the quality on the video image to degrade over time.
What is image compression and what are the types of compression formats used?
CCTV DVR converts analog images to digital and save them in hard disk. Image compression plays an important role of improving transmission as well as reducing storage size. There are various formats of image compression in the market. Among which, JPEG and MPEG format of compression are the most widely used formats in the market currently. The major difference between JPEG and MPEG is in compression techniques. JPEG processes images by compressing one by one still pictures but MJPEG compresses images sequence by sequence. The twin objectives of video compression processing are to reduce the amount of data required to store/send a digital image whilst also maintaining the quality of that digital image. International standards bodies such as the ITU-T and the ISO6 formulate and publish various compression processing standards. There are two main ISO subdivisions that define and regulate image compression standards: namely, JPEG and MPEG. JPEG – Joint Photographic Experts Group is a group of scientists and industrialists who collectively define and regulate standards for the compression of still images (including, for example, photographs and individual frames captured from video footage). MPEG – Motion Picture Experts Group undertakes the same activities in respect of motion video (that is, two or more still images that together form a piece of video footage). These two bodies have set standards such as JPEG (commonly used in digital cameras) and MPEG-2 (the current DVD standard).
What is the maximum length I can pull my cameras away from the DVR?
Using RG59 Coaxial cable, the maximum distance is approx 600 feet away from the DVR and up to 1,000 feet using RG6 Coax. For longer distances, a video amplifier should be used.
Simplex DVR and a duplex DVR:
A simplex DVR only performs one task at a time. The DVR cannot playback recorded videos when it is recording, it can only do so when the recording is stopped. A duplex DVR is able to playback recorded footages without having to stop recording. Recording is uninterrupted and taking place concurrently as you playback the recorded videos.
Some key factors to consider when choosing which DVR to buy are:
•Frame Rate – a higher frame rate will lead to a more fluid playback (rather than a series of broken images) but will also use up more space on your hard drive. For real-time recording and playback look out for 25 fps(frames per second).
•Maximum Hard Drive Capacity – if you only want to store 24 hours worth of footage hard drive capacity won’t be a major issue. If however you want to keep a record of footage for the past few weeks or even months, you’ll need a hard drive with a large capacity to store all of that extra data without running out of space.
•Image Quality & Resolution – capturing a burglar on film won’t be much help if the image is too blurry to see his or her face, so it’s important to consider the quality and resolution of the stored images. However a high resolution will again use up your hard drive space quicker so you may need to find a good compromise between image quality and disk space.
•Backup Facilities – the most common and also the cheapest form of backup for DVRs is via CD. However a DVD backup system can store more footage per disc, or you may wish to opt for a network backup with involves streaming the data onto a computer and converting it to an AVI or other file type.
•Networkability – if you want to watch CCTV footage over the Internet or a network you need a DVR that can do this. Also consider the speed of the network you are using – a Local Area Network has the capability to provide almost real-time streaming but if you are using a slow 512kb upload speed internet connection you will not be getting much benefit from a 25fps frame rate when you can only view 0.5 to 5 frames per second.
NVR (Network Video Recorder):
Unlike its predecessor, the DVR, a NVR is not limited to be in the same area as your cameras cabling to one section. The unit can be placed virtually anywhere, it simply just needs to be on the same LAN network as the IP based cameras. In terms, network video recorders are distinct from digital video recorders as their input is assigned on a network rather than a direct connection to a video capture card. Video on a DVR is encoded and processed at the DVR, while video on an NVR is encoded and processed at the camera, then streamed to the NVR for storage or remote viewing. An NVR is a software program that records video in a digital format to a disk drive, USB flash drive, SD memory card or other mass storage device. An NVR contains no dedicated video capture hardware. However, the software is typically run on a dedicated device, usually with an embedded operating system. NVR is used in IP video surveillance systems. Because of the nature of these units, a camera that is capable of capturing High Resolution (Mega Pixel cameras) will record and playback as that desired resolution unlike a DVR system. Hybrid DVR security systems exist which incorporate functions of both NVR and DVR.
The picture created by the camera needs to be reproduced at the control position. A CCTV monitor is virtually the same as a television receiver except that it does not have the tuning circuits. Images captured by a CCTV Camera system in a store are viewed over an LCD monitor. As with camera sensors the size of monitors is the diagonal measurement of the screen. The distance at which it is to be viewed generally decides the size of monitor. There are two general types of placement for these monitors recommended by Provent, Staff Awareness Monitors and Customer Awareness Monitors.
Staff Awareness Monitors:
Where a retailer wishes staff to be able to view images captured in the store, a Staff Awareness Monitor is connected to the video recorder. The Staff Awareness Monitor is placed at the cash desk so that sales staff can monitor areas of the store not visible from the cash desk.
Customer Awareness Monitors:
To make customers aware that there is a CCTV Camera system within a store, a Customer Awareness Monitor is hung from the ceiling at the store entrance. As customers enter the store, their images are captured by a camera pointing at the store entrance and displayed on the Customer Awareness Monitor.
CCTV on internet and smart phones:
Today Internet Protocol (IP) cameras are very popular kind of CCTV devices. They use the Internet Protocol used by most Local Area Networks to transmit video across the networks in digital form. It can be transmitted through the public Internet, which allows users to view their camera via any broadband connection available via a PC or a 3G phone.
How to view images from analog CCTV cameras via the internet:
Modern CCTV recorders have the ability to act as a web server. DVRs like the DMR4-MPEG4 model have a LAN (Local Area Network) port as standard, hence allowing them to be connected to a network for both local and remote viewing. A simple network can be established by connecting the DVR directly to a PC. The DMR4-MPEG4 recorders are supplied with a simple to use viewing software. Once the program has been loaded on to the PC you can view live and recorded images from the DVR or control most functions of the DVR. Recorded images can be saved to the PC. A more useful configuration can be obtained using a router. For example, a 4 port router will allow the connection of 1 DVR and up to 3 computers. Each computer can then access the DVR data. A broadband router with a live internet connection would allow connection from a remote PC.
CCTV on smart phones and iPhones:
Now you can view live and recorded CCTV Images from your iPhone, iPad or other smart phone. Simply connect your CCTV system to the internet, download the free CCTV App and connect to your security system. With the recent advances of smart phone technology such as the Apple iPhone these devices are suited to real-time CCTV images being displayed on their large colour touch screens. With internet connectivity such as WIFI or fast 3G data access, the reality of connecting directly to your CCTV camera system is now common place.
Firstly you will need to install the relevant software on the recording computer. You may need to perform some routing actions such as, setting up port forwarding. Remote Viewing or Remote CCTV allows you to view CCTV cameras from anywhere in the world via your home broadband connection. You can view the images though your mobile phone or via a laptop or PC. In simple terms you have the Sender (your house) and the Receiver (your laptop/phone etc.) The Sender comprises of one or more cameras connected to a video streamer. The video streamer literarily streams the video signals over either a local network or the internet. In order for the receiver to be able to find the Sender it is allocated a unique IP address or a URL (web address). The receiver comprises either a laptop PC (connected to the internet) or a mobile phone with a small program installed. The user enters the allocated IP or URL address and if required, a user name and password.
Here are some of the benefits of connecting your DVR to your network.
1. Being able to watch your security cameras while you are away from the location is one of the most important features of current DVRs. This will give you the ability to prevent crimes as well as keep an eye on what is currently happening in the locations that the cameras are watching over.
2. Being able to review and back up footage from your DVR remotely so that you have a copy of what is happening even if the DVR ends up getting damaged or stolen.
3. Being able to configure the DVR and specialized cameras remotely. This is handy if you notice that the DVR needs to have some of its configurations modified.
4. Being able to change settings on cameras that are all of a sudden not able to see due to conditions changing. Some people have had issues where their cameras looked great the whole first week that they had them set up but then all of a sudden a big storm comes in and they can’t see anything anymore and one of the camera’s may have a setting which can compensate for this condition change. If you’re not able to reach the location where the DVR and cameras are installed, this will allow you to change the settings from wherever you are so that you don’t miss out on anything in the meantime. However, please note that some cameras do not have these features, but for the ones that do, being able to access them remotely is a great feature to have.
If you install an alarm system as well as CCTV, the alarm system will call your phone if an event occurs. You can then login to your camera system and check the alarm yourself and call the authorities if needed. It’s as easy as that! If you have CCTV only (i.e. no alarm), you have the option to login and view your CCTV footage from any smart phone, tablet or internet-connected computer at any time.
In October 2009, an “Internet Eyes” website was announced which would pay members of the public to view CCTV camera images from their homes and report any crimes they witnessed. The site aimed to add “more eyes” to cameras which might be insufficiently monitored. Civil liberties campaigners criticized the idea as “a distasteful and a worrying development”.
The figure below shows flow diagram of various CCTV systems:
The TV Network Protocol or TVNP as it is more commonly referred to is an open network protocol developed to enable CCTV systems from any manufacturer to be integrated into an existing CCTV network. It provides high levels of support for audio routing, video routing and camera control.
CCTV installation, maintenance and problems:
La Vigne and colleagues (2011) provide 10 lessons for creating a public surveillance system. They are:
1. Assess your needs and budget before investing
2. Plan ahead for maintenance, infrastructure, and other ongoing costs
3. Plan camera locations to maximize the view-shed
4. Consider integration with other technology (e.g. gunshot detection systems, crime mapping software)
5. Balance privacy protection with system utility
6. Weigh the costs and benefits to using active monitoring
7. Integrate camera systems with existing practices and procedures
8. Set and manage realistic expectations for video footage quality
9. Use surveillance systems to complement, not replace, routine policing, investigations, and legal proceedings
10. Incorporate video evidence with witness testimony in court
How to choose a suitable CCTV camera for your needs:
Choosing the correct CCTV Camera that fits your digital surveillance requirements is very important. Here is a simplified set of guidelines when choosing the correct CCTV camera for you application.
a) Location: Indoor or outdoor application
b) Requirement for day and night surveillance
c) The angle of view requirement. Wide angle coverage or a narrow field of view is required.
CCTV camera locations and purpose:
The purpose of CCTV cameras is to observe, detect, recognize and identify.
This is where a person or vehicle (target) occupies 5 percent of the monitor’s viewing height. Cameras located to observe and enable the viewer to know someone was there. The time and date stamp shows what time they were there. The image size will be too small for identification but will place a person or vehicle at the scene when considered with other images i.e.: recognise and identify.
A person or vehicle will occupy 10 percent of the monitor’s viewing height. At this size, the target’s image will be adequate for detection using video motion detection, if installed on the system, but would be too small to identify the person for evidence purposes. If a system is monitored it will provide enough detail to indicate the person is doing something suspicious.
A person or vehicle will occupy 50 percent of the monitor’s viewing height. At this field of view, the target’s image can be recognised if they are already known to staff. They would not be accurately identified if they are unknown. However, the person could be recognised as the same person in different camera shots.
At 120 percent of the monitor’s viewing height, images are of suitable quality to enable identification of individuals and provide distinguishing features of vehicle number plates. Police will have the greatest chance of enlarging the images and capturing vital details.
Choosing the Wrong Lens:
If you or your installation company chooses the wrong lens then there is 80% chance the police will not be able to use your pictures in court.
Choosing the Wrong DVR:
Installing a DVR with too low a resolution again means that your system will be of little use in a police prosecution.
Installing an Illegal System (in UK):
Install a system that does not comply with the Data Protection Act (DPA) and it could result in fine / criminal record, unlimited civil damages and CCTV evidence that is challenged in court.
•The DVR should be installed in a secure location where it will not be exposed to dust/water or extremes in temperature. Like a computer, a DVR generates heat so if placed in a locked cupboard adequate ventilation is necessary.
•Access to the DVR should be strictly controlled by management. If the images are used in a court proceeding, management may be required to name the individuals who were able to access the equipment in order to assure the court that the data was not interfered with.
•A monitor should be installed with the DVR to allow viewing of the recorded vision.
•Cameras should be firmly fixed and should not be subject to vibrations, knocking or other movement that will affect the quality of the images captured.
•Cameras should never look directly into the sun or strong lights since the intensity may burn a permanent spot on the sensitive surface and make permanent white scars in the presentation.
•Cameras located outside a business should be positioned out of reach of passers-by to prevent unauthorised moving or theft. Consider fitting anti-tamper brackets to all externally mounted equipment.
•Ensure there is sufficient light for the camera to view the scene at all times. This may mean installing additional lights or higher wattage globes in existing lights.
•Be aware that at different times of the day the sun, or car headlights, may shine directly into a camera’s lens. Glare will significantly affect the video image. After installation, check the quality of the recordings at different times of the day and night to ensure good quality vision.
•Professional advice is recommended when installing a new CCTV system or upgrading an existing system. Trained consultants can provide advice specifically for your business and the commercial environment in which it operates. Consulting a reputable CCTV company will ensure that your business obtains the best quality CCTV images for both crime prevention and criminal investigation purposes.
•Camera placement is critical to the success of all CCTV systems.
•Recorded vision should be ideally held on the recorder for 30 days before being overwritten.
•Ensure the capture rate is set to provide clear images of the actions of people. Low capture rates have people appearing ‘jerky’ and may miss important evidence of a crime. Faster capture rates make the person’s actions smoother, more natural and capture all of their movements. A minimum of six frames per second is recommended. Twenty-five frames per second is considered to be real time recording.
•However, the higher the capture rate the more hard disk space will be required on the DVR. Therefore, a balance between best practice and best evidence is required. Nevertheless, do not sacrifice the quality of the image to increase the length of time the vision is retained. It is a much better investment to buy a larger hard disk drive.
•Cameras should cover strategic areas that capture the action of people. At least one camera should be set to capture images of people, enabling them to be identified (both from their physical appearance and their facial qualities).
•Camera placement can be determined by sketching out a floor plan. Consider the distance from the camera to the area under surveillance and the field of view the camera will record.
•Ensure cameras are implemented at eye level behind counter areas. This enables a perfect image of an offender. Cameras on ceilings do not assist in identification.
•Ensure that any overhead mounted cameras capture sufficient facial detail of people and avoid the tendency to place a camera up high that will only focus on the tops of their heads.
•Cameras for vulnerable locations should be mounted strategically at areas of high cash turnover and also directly outside premises.
•When setting up cameras in your business, remember to play back the recorded product to ensure the image quality is appropriate. If you can’t distinguish the detail of the person in the image then neither will police.
•If a camera is set simply to cover a wide area it will usually not provide police with sufficient detail to identify the person. It is better to set up a number of cameras, each with a specific purpose. This way, when police view the recorded vision, the individual views will provide sufficient evidence to show what took place.
•Video motion detectors can be used in areas such as fire escape stairwells, health spas, and swimming pools that are used infrequently. When the CCTV system is activated and movement occurs at the target location, the DVR unit commences recording. However, do not use video motion detection on an external application without careful planning.
CCTV system maintenance and management:
For CCTV vision to be useful to investigators and accepted in a court of law, its integrity needs to be ensured. Evidence is required to show that the CCTV system has been maintained and the data appropriately managed according to the following guidelines.
•All systems should be regularly maintained and tested.
•One of the primary maintenance issues associated with CCTV systems is keeping the glass front of the housing clean. To this effect, some camera housing units actually come with their own blades and wiper fluid dispenser. Ensure that camera protective coverings are clean as a build-up of dust or dirt will degrade recorded images.
•Dome enclosures for interior ceiling-mounted cameras need to be kept free of dust and other materials.
•Each week a check should be made of the system’s time and date against a known accurate clock.
•On a weekly basis management should review the vision recorded from each camera to ensure the images are still being captured with the desired view and that they are still in focus.
•Visually check the mountings of all cameras weekly to ensure they are still securely fixed and have not been accidentally bumped or tampered with.
•A written maintenance log should be kept for the CCTV system. The log should record what checks were conducted and the details of who conducted them. It should be signed by the person completing the checks at the time they were carried out.
•Remember, all CCTV equipment has a finite life span but usually greater than 5 years. It is recommended that a maintenance contract be secured to cover CCTV installations. Such maintenance usually serves to extend the lifespan of the equipment. Plan to replace your system according to the manufacturer’s recommendation.
•Recorded vision will only be useful in evidence if its integrity can be assured.
•Therefore, recorded vision must not be manipulated, changed or enhanced in any way.
•The number of employees who have access to the CCTV equipment and the vision data should be limited to those essential for the system’s maintenance.
•Provide training on the operation of the system to key staff who will be providing police with the recorded vision. Where possible, it is preferable the staff members selected for this role are likely to be on site or readily contactable in the event of an incident so that video footage can be quickly provided to police.
•It is important to have the CCTV system documented and a user manual on hand that describes how the system operates. These can be kept with the maintenance log.
•The person who provides the vision data to police will become a witness. They should have a good understanding of the CCTV system and be able to give evidence in court on the steps they took to make a copy of the data for the police.
Technical problems vis-à-vis CCTV:
Many technical problems hinder the effectiveness of CCTV systems, and several of these problems are not addressed or even recognized in the first place. The lack of training and available manuals/guidelines is a major hindrance. Yet, the question to ask is: with ongoing advancements and changes of CCTV products as well as the vast diversity, can training and manuals be made available at such a pace? With the rapid changes occurring in the realm of CCTV technology, technical problems are bound to occur and the local security person accessing the CCTV central system is ill prepared for a breakdown or malfunctioning. Moreover, cameras can pose additional problems: limited area of coverage, poor design and tape quality, improper use, lack of maintenance and lack of enthusiasm by the users. These issues are crucial in terms of recognizing that technical problems hinder the effectiveness of CCTV systems, and several of these problems are not addressed or even recognized in the first place. The lack of training and available manuals/guidelines is a major hindrance.
CCTV System Problems Solutions vis-à-vis Camera:
No image out:
•Check power supply connection normal or not, voltage sufficient or not.
•Whether BNC adapter or video cable is in poor contact
•Whether lens aperture is open.
•Whether video cable and AC auto aperture lens cable connect well
Image quality poor:
•Whether lens has fingerprint or dirty
•Whether aperture is adjusted well
•Video cable is in poor contact.
•Whether electronic shutter setting or white balance setting has problems
•Whether transmission distance is too long
•Whether voltage is normal
•Whether there is interference source nearby
•Inner-elevator installation should avoid interference by ensuring camera insulates with elevator.
•Whether CS-mount is correct
Problems caused by overlong distance transmission and solutions:
•Monitor picture contrast too low, image weak:
This appearance reason lies in control server, monitor, overlong distance transmission or transmission signal loss too much. In such situation, adding cable amplifier kit and compensation kit is needed.
•Image definition low, details loss, even color signal loss or saturation under-standard:
This appearance is caused by that high frequency signal is damaged too seriously and frequency (over 3MHz) loses mostly. This problem is caused by many reasons which include transmission distance overlong (without amplifier & compensation kit), distributed capacitance overload in video transmission cable, equivalent capacitance centralized between transmission cable core and screened wire.
This appearance happens easily during long distance video transmission. The main reason lies in high-frequency section phase shift overdone. In such condition, adding phase compensation is needed.
CCTV power consumption and durability:
A CCD type CCTV camera is usually very durable partly because of its sturdy construction and because its electronic circuitry are operated by a stable power supply. They may last for many years without any problems. Most these cameras operate between -10˚ to 50˚ (Celsius scale). If a camera is to operate outside where temperatures fluctuate beyond these ranges, the CCTV technician must install a protective enclosure containing a heater and a blower. Otherwise, the equipment will malfunction or breakdown.
Choosing a Power Supply:
Each camera has its own level of power required. Most of the cameras require a 12V DC power supply but some have built in 12/24V adapters and others need 230V AC power to function. High voltage 230V cameras required a qualified electrician to connect them to the mains so if you want to install the camera yourself opt for a 12V DC camera. It is important not to supply the camera with more voltage than it is rated for as it will simply blow the board and render the camera useless. You can however over-supply amps as the camera will only take what it needs. A 12V or 24V camera requires a special power supply to convert the 230V mains power to the appropriate level. A power supply unit, or PSU, is available as individual plug-in units up to 1 Amp for single cameras, or metal boxed power supplies up to 3 Amps for multiple cameras. For example, a CCTV system with eight 12V cameras consuming 0.2 Amps each would require at least 1.6 Amps from the power supply.
The table below shows number of frames of video recorded in 80 camera CCTV system in 24 hours:
As you can see enormous information is available through CCTV system.
The applications of CCTV:
The most common use of Closed Circuit Television is in security systems and such applications as retail shops, banks, casinos, malls, condos, government establishments, home security, etc. The true scope for applications is almost unlimited.
Some examples are listed below.
1. Home Security Cameras for monitoring babies
2. Recording how their caretakers treat your elders at homes or nursing homes
3. A Television Security Camera System to check the surroundings of a block or a building
4. Television Cameras for Quality Control in factories or laboratories
5. Security Television Cameras for checking parts storage in an auto repair shop
6. Covert Cameras hidden in buses to control vandalism
7. Cameras for aerial photography from a small airplane or helicopter
8. Mini cameras or other Television Cameras for production control in a factory
9. Monitoring traffic on a bridge
10. Recording the inside of a baking oven to find the cause of problems
11. A temporary system to carry out a traffic survey in a town centre
12. Time lapse recording for the animation of plasticine puppets
13. Used by the stage manager of a show to see obscured parts of a set
14. The well-publicised use at football stadiums
15. Making a wildlife program using a large model helicopter
Home security through home CCTV:
Humans have always felt very possessive of their belongings. During ancient times, inhabitants used to live in secure caves so that they would be protected from unwanted intrusion and from deadly animals. The advancement of civilization witnessed better and improved means of home security system being implemented by humans. Technological revolution of modern age has resulted in concept of home security finding widespread popularity. Everyone worth his salt thinks of protecting his hard earned possessions. Urban population specifically has become very conscious of the important aspect of home security. Nowadays, it’s not unusual for homeowners to install security cameras around their homes and property to protect against trespassing, burglaries and vandalism. While the cameras themselves can’t do anything to physically prevent crimes from occurring in an around the home, they’ve become very effective deterrents – a well-monitored home is far less appealing to criminals than one with no security measures in place. Another form of CCTV surveillance in the home is the “nanny-cam,” a small video camera that is often disguised to look like an ordinary household object, and placed in an area of the home where nannies, babysitters, and other household staff/employees are likely to spend time. These undercover security cameras bring peace of mind to parents and homeowner who want to be reassured that their children and belongings are safe and being treated appropriately.
CCTV and crime:
Before evaluating the effectiveness of CCTV in reducing crime, it is necessary to understand the theory behind its use. According to Weiss, one of the types of crime prevention has particular relevance with regard to the use of CCTV – “Primary Crime Prevention is focused on the offence rather than the offender, and is often associated with situational crime prevention strategies which focus on the immediate and localized context of the offence”. This type of crime prevention is based on rational choice theory and assumes that the individuals most likely to commit crimes are the ones who believe that they can get away with it. Thus by employing CCTV, the confidence of aspiring criminals is shaken as they are cognizant of the fact that they may be apprehended or they may feel the cameras are watching their every move , and are loathe to risk capture and consequently they may refrain from committing the crime. Criminal recklessness is replaced by fear. As Tilley (1993) puts it, “CCTV could reduce crime by increasing the likelihood that present offenders will be caught, stopped, removed, punished and therefore deterred”. Thus when used in this particular context, CCTV seeks to reduce the opportunity to commit crime and thereby deter the potential criminal, by increasing the chances of getting caught. Situational prevention can also cause a reduction of crime, by means of diffusion of benefits. According to Clarke and Weisburd (1994), “The term refers to the fact that situational prevention can often bring about reductions in crime beyond the immediate focus of the measures introduced”. This additional benefit was demonstrated with regard to the use of CCTV in a case described by Poyner (1991), where CCTV cameras used to prevent theft in the car park at the University of Surrey not only reduced theft in the three areas being monitored, but in one not under surveillance.
It is argued that CCTV (especially if well publicized) may prevent crime because potential offenders are deterred by their increased subjective probability of detection. Also, CCTV may increase the true probability of detection, may increase pedestrian usage of places and hence further increase the subjective probability, may encourage potential victims to take security precautions, and may direct police and security personnel to intervene to prevent crime. Another possibility is that CCTV could signal improvements in the area and hence increase community pride, community cohesion, and informal social control. CCTV could also cause crime to increase. For example, it could give potential victims a false sense of security and make them more vulnerable because they relax their vigilance or stop taking precautions, such as walking in groups at night and not wearing expensive jewelry. It may encourage increased reporting of crimes to the police and increased recording of crimes by the police. CCTV may also cause crime to be displaced to other locations, times, or victims. Analysis of crime data shows that, at least in the short term, the presence of closed-circuit cameras can have a deterrent effect on a variety of offenses, especially property offenses. For example, in the section of Newcastle covered by CCTV, burglaries fell by 56 percent, criminal property damage by 34 percent, and nonmotor-vehicle theft by 11 percent.
How does CCTV prevent crime?
The general purpose of the CCTV is to prevent and reduce crime. In theory, this happens because of one or more of these reasons:
1: Deterrence – potential burglars and thieves may see the camera and decide that a store in question is too much of a risk and therefore not a good target
2: Prosecution – thieves and shoplifters may be caught on camera and this can help catch and prosecute them
3: Fear reduction – if everyone knows that there is a camera, they may feel safer in or around your business, thus preventing potential criminals from attacking
4: Monitoring and intervention – if there is a security guard monitoring the area through CCTV system, he or she may act on any suspicious behavior and thus prevent a crime from occurring. Security guards may also deploy employees to a suspicious spot or near a person detected on the monitors.
CCTV systems can vary in terms of whether they involve either active or passive monitoring:
Active monitoring by operators who monitor the cameras in real time can increase the threat of identification and help mobilise a response as operators may have open channel communication with the police. Passive monitoring refers to CCTV systems that regularly scan an area and produce a record that can later be examined, assisting with collecting evidence.
Closed circuit television (CCTV) systems can be used to enhance the safety and security of your business, CCTV footage can also provide valuable assistance to the police when investigating crimes and prosecuting offenders.
The use of CCTV systems includes the following:
•The presence of CCTV cameras may serve as a deterrent to inappropriate or illegal activity. This is the preferred role of CCTV systems – to prevent or reduce the opportunity for crime to occur.
•CCTV cameras can be used to provide real-time or recorded surveillance over large areas, i.e., the perimeter boundary of protected property, parking lots, retail stores, government buildings, etc. This use of CCTV is sometimes referred to as video patrol.
•CCTV cameras can be integrated with other sensing systems (robbery or burglary alarms), and used to view areas not immediately accessible to personnel. This is often referred to as “event-driven cameras.”
•CCTV cameras and monitoring equipment can provide an historical recall of events. Good quality preserved CCTV images can provide valuable information and evidence for police related to inappropriate or illegal activity.
•CCTV cameras may have a better viewing vantage than personnel.
If good quality CCTV footage of an incident is available, this can assist police to clear up an investigation in a short time and successfully prosecute the offender. Unfortunately, many CCTV systems are not installed properly, have not been maintained, provide poor quality video footage or are switched off/broken at the time of the incident. If evidence is gained from a CCTV system in such cases, it may be excluded by a court. A poorly installed, maintained, or functioning CCTV system is only marginally better than having no CCTV system at all.
The attributes of a good system that police can use for investigating crime are listed below:
•Colour CCTV systems are the preferred system because they generally provide better evidence than black and white (sometimes referred to as monochrome). They permit a more realistic view of the image and make identification of persons and things easier because of the more natural image. However, they do need a greater amount of light than black and white cameras and are of lower resolution (picture quality). Therefore, a minimum of 300-400 lines of horizontal resolution is recommended. Also bear in mind that colour CCTV is also more expensive than black and white cameras.
•All systems should record vision from all cameras at all times while the system is turned on. Generally, it is recommended that a CCTV system operates on a 24-hour basis.
•Digital Video Recorders (DVRs) are the preferred medium of choice for recording and storing images. DVRs have computer-style hard disk drives and have longer recording periods than Video Cassette Recorders (VCRs), which are now no longer manufactured. The image files of DVRs are of superior quality, do not degrade over time, require less storage space, are easier to search and can be viewed on a computer via a network. New data is also automatically written over the oldest vision once the hard drive is full.
•All recorded vision should be watermarked with the time, date and camera number/description that recorded it.
•The digital recorder used should be capable of generating a copy of the recorded vision so that it can be given to police investigators along with any special software required to view it.
•Dummy cameras are not recommended.
•Consider installing a small uninterrupted power supply (UPS) to provide power to both DVR and cameras should mains power fail.
•Signs warning that CCTV is in use increase the deterrent effect of CCTV cameras.
Crime solving using CCTV in UK:
There is strong anecdotal evidence that CCTV aids in detection and conviction of offenders; indeed UK police forces routinely seek CCTV recordings after crimes. Moreover CCTV has played a crucial role in tracing the movements of suspects or victims and is widely regarded by antiterrorist officers as a fundamental tool in tracking terrorist suspects. Large-scale CCTV installations have played a key part of the defenses against terrorism since the 1970s. Cameras have also been installed on public transport in the hope of deterring crime, and in mobile police surveillance vehicles, often with automatic number plate recognition, and a network of APNI-linked cameras is used to manage London’s congestion charging zone. Even so there is political hostility to surveillance and several commentators downplay the evidence of CCTV’s effectiveness, especially in the US. However, most of these assertions are based on poor methodology or imperfect comparisons. A proactive arrest happens when a council CCTV operator either alerts the police to an incident, or leads the police to a suspect after hearing a call out on the police radio and identifies the suspect using CCTV at the time of the incident. Hundreds more arrests take place as a result of police officers reviewing video and suspects being identified at a later date. CCTV is one of the most powerful tools to be developed during recent years to assist with efforts to combat crime and disorder. Another success story involved CCTV tracking down a vehicle carrying a huge haul of Class A drugs and cash. CCTV acts as deterrence rather than prevention to crime. CCTV deters ‘opportunistic’ crime, where people take advantage of a situation on the spur of the moment. The cameras are also creating a vastly increased rate of conviction after crimes are detected. Virtually everyone caught committing an offense on camera pleads guilty nowadays. Once people know they have been videotaped, they admit the offense immediately.
•In 2009, The Daily Telegraph revealed that almost seven out of ten murders are solved using footage captured by CCTV cameras.
•The study looked at the effectiveness of surveillance cameras, and revealed that almost every Scotland Yard murder inquiry used CCTV footage as evidence. Over a one year period, 86 out of 90 murder cases used CCTV in the investigation. Senior Officers claimed that 65 cases were solved by either capturing the murder itself on film, or using surveillance to track the movements of suspects before or after an attack.
•In 2010, BBC News reported that according to the Metropolitan Police, CCTV cameras across London help to solve almost six crimes a day. In 2009, the number of suspects who were identified using the cameras was 1,970, increasing to 2,512 in 2010.
•CCTV also played a vital role in Police crack-downs following the August 2011 riots. London Evening Standard revealed that almost 3,000 people suspected of offences in London during the riots had been arrested. The Metropolitan Police confirmed that CCTV acted as one of the main investigative leads, with officers reviewing thousands of hours of footage to detect suspects.
•CCTV also helped identify the “London Nail Bomber”, David Copeland, in 1999. Copeland’s nail bombs killed three people and injured 139, with four victims losing limbs. CCTV images of Copeland were given wide publicity, with a work colleague of Copeland’s alerting the police. He was convicted of murder in 2000.
•CCTV evidence from the New Strand Shopping Centre in Bootle also identified Robert Thompson and Jon Venables as being responsible for the abduction and eventual murder of James Bulger in 1993.
Research that utilizes the scientific realism approach developed by Pawson and Tilley (1997) tried to identify how CCTV works and specifically in what contexts. Academics (Armitage et al, 1999; Tilley 1993) have documented several ways or mechanisms that could result in CCTV bringing about change in an area and those devised by Tilley are as follows:
•Caught in the act – CCTV could reduce crime by increasing the likelihood that present offenders will be caught, stopped, removed, punished and therefore deterred.
•You’ve been framed – CCTV could reduce crime by deterring potential offenders who will not want to be observed by CCTV operators or have evidence against them captured on camera.
•Nosey Parker (overly inquisitiveness) – a reduction could take place because more natural surveillance is encouraged as more people use the area covered by CCTV. This may deter offenders who fear an increased risk of apprehension.
•Effective deployment – CCTV may facilitate the effective deployment of security staff and police officers to locations where suspicious behaviour is occurring. Their presence may deter offenders, or may mean they are caught in the act.
•Publicity (general) – this may assist in deterring offenders.
•Publicity (specific) – CCTV cameras and signs show people are taking crime seriously, and thus offenders may be deterred.
•Time for Crime – CCTV may have less of an impact on crimes that can be done quickly as opposed to those that take a longer time, as offenders assume that they will have enough time to avoid the cameras, or to escape from police officers and security staff.
•Memory jogging – publicity about CCTV encourages potential victims to be more security conscious and to take precautionary measures.
•Appeal to the cautious – those who are more security minded use the areas with CCTV, driving out the more careless who are vulnerable to crime elsewhere.
The list above represents a starting point to consider how CCTV can impact on crime and numerous other mechanisms can be developed across a range of settings and offence types (Ratcliffe, 2006). Coupe and Kaur (2005) examined the impact of CCTV and alarms in detecting commercial burglary and they highlighted the complex interplay of mechanisms that can result in CCTV impacting on crime and how different crime prevention measures can have conflicting mechanism. CCTV can provide evidence on film that leads to arrest, while visible CCTV cameras like alarms, may also deter burglars or displace them to other targets. In addition, visible or hidden CCTV cameras may alert a watchman or employee to the commission of a crime. On the other hand, activated alarms may frighten burglars so that they quickly flee the scene, reducing not only capture there, but also, where CCTV is additionally fitted inside the premises, of a subsequent arrest by catching the offender on film. Although CCTV will not increase actual levels of crime, the increased surveillance may result in more offences coming to the attention of the police, particularly violent offending (Brown, 1995).
The range of additional crime reduction measures that often operate alongside CCTV system make it difficult to isolate the impact of the cameras and these can include changes to policing practices (Webb and Laycock, 1992), ad hoc police operations, improved lighting, community wardens and youth inclusion projects (Gill et al, 2007). Using crime statistics alone to evaluate CCTV means that many of the potential benefits of the cameras can be missed including supporting police activity leading to cost savings in relation to police time, increased detection rates, court time and the increased level of guilty pleas and guilty verdicts obtained when CCTV evidence in available (Home Office, 2007).
CCTV can work on a number of different levels across a range of different contexts and this has resulted in mixed research findings in terms of CCTV effectiveness. Welsh and Farrington (2002) conducted a meta-analysis on studies of CCTV effectiveness and collected 46 studies but only considered 22 of the research papers to be rigorous enough for inclusion in their review. Half (eleven) of the studies found a desirable effect on crime, five found an undesirable effect on crime, five found a null effect, and one was classified as an uncertain effect. The largest impact on CCTV was found across car parks where there was evidence that crime reduced by 41% in the experimental compared to control area, which was significant. The research identified that CCTV had little or no effect on violent crime but the authors advocated the need for more high quality research that ‘established the causal mechanism by which CCTV has any effect on crime’ which should involve methodologically rigorous evaluations and interviewing offenders. A further meta-analysis of CCTV studies conducted in 2008 by Walsh and Farrington confirmed earlier findings that CCTV was effective in car parks and they advocated narrowing the use of CCTV to reflect research findings related to its effectiveness.
The Home Office’s National Evaluation of CCTV (Gill and Spriggs, 2005) attempted to address some of the deficiencies identified in previous CCTV evaluations by combining a process and impact evaluation that incorporated control areas and identified other crime control initiatives that were operating in the target area to evaluate their impact on recorded crime levels. Thirteen CCTV systems were evaluated across a range of system including town centers, city centers, car parks, hospital and residential areas. The inclusion of residential areas reflected the governments push to include these types of areas into the Phase 2 of the Crime Reduction Program(Home Office, 2007). The main findings were: Out of the 13 systems evaluated six showed a relatively substantial reduction in crime in the target area compared with the control area, but only two showed a statistically significant reduction relative to the control area, and in one of these cases the change could be explained by the presence of confounding variables. Crime increased in seven areas but this could not be attributed to CCTV. The findings in these seven areas were inconclusive as a range of variables accounted for the changes in crime levels, including fluctuations in crime caused by seasonal, divisional and national trends and additional initiatives.
CCTV systems rarely work in isolation and often form part of a crime prevention strategy. Webb and Laycock (1992) found evidence that CCTV can reduce robberies on the London Underground but the cameras were part of a package of measures to reduce crime in the area that made it difficult to identify the impact of the cameras alone. The research concluded that ‘CCTV does not seem to be very useful in large complex and crowded environments to deal with surreptitious behaviour such as pick pocketing or shoplifting’ (Webb and Laycock, 1992: 23) as the quick nature of the offences made it unlikely that they would be picked up by operators. Given that it was unlikely offenders would be detected by the cameras their effectiveness was mainly linked to whether offenders associated the cameras with an increased risk of getting caught on the London Underground.
CCTV is a type of situational crime prevention and is often used to facilitate a change in the behaviour of offenders. Mayhew (1984) suggested that formal surveillance would deter potential offenders and this follows the rational choice theory perspective (Clarke and Felson, 1993) that proposes offenders act in a rational manner and by calculating whether the perceived benefits outweigh the cost in a given situation. The application of the deterrent effect of CCTV to routine activity theory means that the presence of CCTV can be perceived to act as the capable guardian and therefore demotivate offenders. The majority of CCTV systems rely on the deterrent effect of the cameras but the deterrent is often symbolic and ‘more or less incompetent deterrence because cameras are highly visible but those under surveillance are hardly visible for an observer due to irregular monitoring, informational overkill or even deployment of dummy cameras’ (Hempel and Topfer, 2004: 33).
Research has examined the effect of CCTV on offenders’ behaviour across a range of contexts and identified that CCTV tends to be an effective deterrent against planned offences. Allard, Wortley and Steward (2008) examined whether the presence of CCTV in prisons reduced the number of incidents that were defined as ‘breaches of law or rules that may result in criminal prosecution or breach hearings and emergencies’. The research found that CCTV had a greater impact on non-violent than violent prisoner misbehaviour and affected planned behaviour to a greater extent than unplanned behaviour. The spontaneous nature of violence means that the deterrent effect of CCTV can be removed and it tends to be more ‘effective when behaviour is motivated’ (Allard et al, 2008: 416).
CCTV does not create a physical barrier to crime and therefore can rely to a large extent on changing offenders’ behaviour. Therefore key to the success of CCTV is offenders’ views regarding its effectiveness. Evaluations that use crime levels to investigate the impact of CCTV on offenders need to be supplemented with offender interview based research to develop a full picture of how CCTV can be utilised fully to address criminal behaviour (Farrington and Walsh, 2002; Gill and Loveday, 2003). Gill and Loveday interviewed 77 convicted offenders in prison and the general consensus amongst those interviewed was that they did not worry about CCTV but there was evidence that some offenders chose to take precautions against the cameras by wearing clothes that hid their identity or offended in camera blind spots. Many of the offenders committed ‘swift offences’ and therefore believed that police notified by the cameras would not arrive in time to apprehend them (see also Short and Ditton, 1998). Roughly half the sample of offenders believed that CCTV increased the risk of getting caught but those that had been caught by CCTV perceived it as more of a threat. There was a lack of understanding amongst the offenders regarding image quality and how the images could be used to increase detection. The types of mechanisms that need to be utilised to increase the perceived risk of CCTV for offenders include using publicity detailing successes of the cameras and the capabilities of systems.
A survey of offenders asked that if they knew CCTV was present, would they have still offended?
16% had offended even though they knew CCTV was present.
53% said there was no CCTV where they offended.
31% did not know if CCTV was present or not and did not much care.
This relatively high figure suggests that for a good number of offenders CCTV does not figure highly in any risk assessment undertaken prior to commission of the offence. When the offenders were asked if they would still have committed their offences if they knew the CCTV had been operational 48.2% said no, 27.7% did not know and 24.1% said they would still have offended (and this rises to 40% for juvenile offenders), suggesting that some offences may be prevented whereas others will still occur.
CCTV cost-effectiveness vis-à-vis crime:
A more open question is whether most CCTV is cost-effective. CCTV systems sales jumped by almost 700 percent from 1980 to 2000. As you can imagine, crime cameras don’t come cheap. In fact, Great Britain’s Ring of Steel cost more than $330 million from 1999 to 2001. With all the money being pumped into these mechanized eyes, you might wonder how well they curb crime. That depends on who you ask. Law enforcement officials generally support them, citing significant drops in violent crime. On the other hand, comprehensive studies by the American and British governments have shown otherwise. Massive investment in CCTV cameras to prevent crime in the UK has failed to have a significant impact, despite billions of pounds spent on the new technology. Only 3% of street robberies in London were solved using CCTV images, despite the fact that Britain has more security cameras than any other country in Europe. While low-quality domestic kits are cheap, the professional installation and maintenance of high definition CCTV is expensive. Gill and Spriggs did a Cost-effectiveness analysis (CEA) of CCTV in crime prevention that showed little monetary saving with the installation of CCTV as most of the crimes prevented resulted in little monetary loss. Critics however noted that benefits of non-monetary value cannot be captured in a traditional Cost Effectiveness Analysis and were omitted from their study. There has been discussion over the installation of CCTV as a cost-effective means for replacing the police force. However, almost every alternative crime prevention strategy has been shown to be cheaper and more effective. For example, while policemen on the beat become more effective in helping to reduce crime, cameras become less effective over time. A system of twenty city centre cameras is equivalent to the cost of thirty full time police. Crime prevention budgets are now being expended exclusively on CCTV, while tried and tested community based strategies find their funding has been eliminated. Heidi Mork Lomell (2004) suggests that CCTV systems are not a replacement for the police force, but enhance their work. Don Babwin (2007) asserts that unlike security personnel, cameras are not subject to fatigue or loss of concentration and therefore provide uninterrupted and consistent effort. Therefore, the financial burden of the initial expense of purchasing and installing the system is thwarted by its long-term efficiency over employing additional police officers who may be less valuable. Moreover, CCTV systems are also a key tool for helping police forces in solving crimes.
A 2008 meta-analysis of CCTV effectiveness on crime:
Multiple crime/offense types:
Welsh and Farrington (2008) found that closed circuit television (CCTV) had a significant, though modest, impact on crime. Through aggregating the results of 41 studies, the authors found an overall effect size of 1.19, meaning that CCTV was associated with a 16 percent reduction in overall crime.
Welsh and Farrington (2008) aggregated the results from 22 studies that examined the impact of CCTV on vehicle crimes and found a significant effect size of 1.35. This indicates that CCTV reduced vehicle crimes by 26 percent.
Welsh and Farrington (2008) examined the impact of CCTV on violent crime reported in 23 studies and found a nonsignificant effect size of 1.03. Overall, this indicates that CCTV does not have an impact on violent crimes.
A 2009 analysis by Northeastern University and the University of Cambridge, “Public Area CCTV and Crime Prevention: An Updated Systematic Review and Meta-Analysis,” examined 44 different studies that collectively surveyed areas from the United Kingdom to U.S. cities such as Cincinnati and New York.
The analysis found that:
1. Surveillance systems were most effective in parking lots, where their use resulted in a 51% decrease in crime;
2. Public transportation areas saw a 23% decrease in crimes;
3. Systems in public settings were the least effective, with just a 7% decrease in crimes overall. When sorted by country, however, systems in the United Kingdom accounted for the majority of the decrease; the drop in other areas was insignificant.
Location of CCTV and its effect on crime:
Such studies are criticized for the inclusion of confounding variables (e.g. notification of CCTV cameras on site, improved street lighting) found in the studies analyzed (including car park studies). These factors could not be differentiated from the effect of CCTV cameras being present or absent while crimes were being committed. Thus, a combination of factors might be important for the decrease in crime not just the CCTV cameras.
Effects of Closed-Circuit Television on Crime: 2013 study:
This article reports on the findings of a systematic review–incorporating meta-analytic techniques–of the available research evidence on the effects of closed-circuit television (CCTV) on crime in public space. A number of targeted and comprehensive searches of the published and unpublished literature and contacts with leading researchers produced twenty-two CCTV evaluations that met criteria for inclusion in this review. CCTV had a significant desirable effect on crime, although the overall reduction in crime was a rather small 4 percent. All nine studies showing evidence of a desirable effect of CCTV on crime were carried out in the United Kingdom. Conversely, the other nine studies showing no evidence of any desirable effect of CCTV on crime included all five North American studies. CCTV was most effective in reducing crime in car parks. It had no effect on violent crimes but had a significant desirable effect on vehicle crimes.
Does CCTV Displace Crime? [Criminology and Criminal Justice, May 2009, Vol. 9, No. 2, 207-224]
Crime displacement is a concern often raised regarding situational crime prevention measures. A national evaluation of closed circuit television cameras (CCTV) has provided an interesting test-bed for displacement research. A number of methods have been used to investigate displacement, in particular visualization techniques making use of geographical information systems (GIS) have been introduced to the identification of spatial displacement. Results concur with current literature in that spatial displacement of crime does occur, but it was only detected infrequently. Spatial displacement is found not to occur uniformly across offence type or space, notably the most evident spatial displacement was actually found to be occurring within target areas themselves.
CCTV effectiveness in reducing anti-social behavior (ASB): A study:
It seems that currently there is very little literature or research evaluating the effectiveness of CCTV in reducing antisocial behaviour. As antisocial behaviour can be an antecedent to more serious crime it is important to know which initiatives are effective in reducing the likelihood of it occurring. CCTV is a situational crime prevention method, a way to design out crime. The aim of this research was help to bridge the gap in knowledge in the area of the effectiveness of CCTV in reducing antisocial behaviour with the use of both primary and secondary sources. The results were startling, showing CCTV to have little impact on the level of antisocial behaviour in one area and the opposite in another area, as seen in the figures below.
CCTV reducing ASB:
CCTV has no impact on ASB:
As with all community safety strategies CCTV has a finite life cycle, so the effectiveness of CCTV in reducing crime and ASB must be monitored closely to ensure that any success rate is maintained. Property crime rates such as criminal damage, which falls under the category of ASB, began to increase a mere eight months after the installation of CCTV, making it essential that success stories are regularly brought to public attention, both to deter potential offenders and to reduce fear in the general public. Nacro found that street lighting was just as effective as the installation of CCTV cameras in reducing ASB and crime, but this does not tackle the issue of the fear of ASB or crime so in relation to the fear maybe CCTV is the right initiative to implement. Felson and Clarke (1998) theorise that crime can be displaced. By changing the opportunity for criminal acts to occur, such as installing CCTV cameras, crime can be moved from one place to another which has led to the government installing CCTV in residential areas as well as in town centers. The increased levels of surveillance may displace crime into the more deprived Wards, the Wards or areas where there is not a large enough budget to install CCTV, which could in turn, make the situation worse in those areas. In this sense CCTV is not a positive initiative and may increase the negative attitudes held about it.
Is CCTV is an effective safety tool for reducing crime?
For certain institutions, government agencies and social science researchers, CCTV technology is deemed as an efficient and successful tool for reducing crime rates within targeted areas. There have been, and continue to be, countless studies devoted to proving this stance and asserting the claim that CCTV systems are useful and at times the best solution. Such studies suggest that CCTV systems have preventative and reactive measures, revive business in desolate or poor areas, increase the efficiency of the police force, build social cohesion, protect the private environment of citizens and assure confidence and ensure feelings of safety and security, thus leading to a more ordered and stable society. However, opponents of CCTV technology claim that there is too much focus on the ability of CCTV to reduce crime. John Honovich (2008) states that such a focus produces misleading studies and draws away from a proper assessment and evaluation of the impact of CCTV on solving crime. Instead, he calls for a shift of the focus towards a structural approach; exploring the roots causes of crime. Most studies that found a causal link between CCTV use and reduction in crime were usually associated with property crimes or car park offences. The UK-based organization Nacro conducted a review of CCTV studies and found that property crimes reduced in areas covered by video surveillance, especially in car parks (car theft). It is commonly found that the presence of cameras in public spaces has had a positive impact on the crimes outlines above. However, the same Nacro review revealed that public video surveillance had no impact on personal crimes (assault, drunkenness). Helten and Fischer’s study (2004) in Germany reveals a similar point, whereby CCTV had little or no effect on reducing, what they term as, ‘crimes of passion’ such as public drunkenness and acts of rage. These studies demonstrate the ineffectiveness of CCTV as a crime reducing tool and moreover suggest that either there is a general lack of awareness of video surveillance cameras or an overall indifference. Other studies have explored the situation of ‘Diffusion of Benefits’ or ‘Displacement’, whereby once potential offenders are aware of public cameras they change choice or location of the crime (IACP). In the end, there is no reduction in the overall crime rate. This situation was found mainly for robbery and theft, which according to CCTV advocates are the most prominent and reduced crimes. An example of displacement is found in the Montreal pilot project on video surveillance cameras. In 2004, the Montreal police installed cameras on St. Denis to monitor and assess the effect on reducing criminal activities in the area. St. Denis, located near the Berri-Uqam metro station, is known for illicit drug deals and other criminal activities. Shopkeepers and residents have expressed concern. The study’s findings reveal that the targeted areas for video surveillance did have reduced rates of criminal activities (10% less robberies, 15% less selling of drugs) (Charest et al., 2005). This reduction was specific to the daytime. However, it is important to note that at the same time, there was an increase of police patrolling and arrests in the select areas. Critics of the study suggest that overall rates did not reduce due to the displacement effect. Once individuals knew of the cameras and noticed the increase in police they tended to moved location. One of main critiques surrounding video surveillance is that it is a ‘quick-fix’ solution and fails to tackle the real problems. In this case, social structures are discriminating and uphold disparities, which fuels crime. In Sutton and Wilson’s (2004) study in Australia, their findings reveal that most individuals interviewed noted video surveillance as irrelevant or unhelpful. The central critique was that video surveillance does not deal with the root problems or the causes of crime. Specific issues referred to economic and social inequalities, such as welfare support and housing were the main causes, which CCTV cannot and does not address, recognize or reduce. Aside for a desire to shift the focus, opponents of CCTV systems claim that there is a significant absence of evaluation, especially independent evaluation on the impact of video surveillance on crime reduction and prevention. Honess and Charman’s research (1992) on individual’s awareness of CCTV systems reveals that there was no proper assessment of the outcome of installing CCTV systems. Furthermore, interviewees expressed concern that there is no body of independent research being conducted on the use and end product of video surveillance in their locations. These points make us question CCTV technology’s ability to reduce and solve crime.
Is CCTV is an effective safety tool for building feelings of security?
In the event of reduced crime, increased feelings of security and safety can have positive impacts on the social cohesion of a community, region or even a state. Ann Rudinow Sætnan et al. (2004) claim that CCTV systems have been instrumental in reducing crime and thus building relations in a once volatile and unsafe area. Increased citizen safety encourages broad participation and interaction in public spaces, which is effective in improving a community’s profile and attracting investment (Sætnan et al. 2004). Moreover, increased stability in a specific area can have advantages for economically revitalization, in which the area will attract more investment internally and externally, leading to an improvement in the social status and quality of life of its residents and a reduction in crime. According to several researchers, CCTV does not reduce feelings of insecurity or safety, proving its ineffectiveness as a crime preventing, reducing and solving tool. Jason Ditton (2000) claims that CCTV cameras do not make people feel safer, but create a false fear, which is enhanced by intense media activity. Further, the camera targets the (innocent) citizen rather than the criminal, imposing a constant fear in public spaces. Terry Honess and Elizabeth Charman’s study (1992) found that whether it was in car parks, shopping centers or on the street, the presence of video surveillance did not make the public feel safer. Their results reveal that feelings of discomfort and increased fear in the presence of video surveillance was significantly higher among women, who are commonly labeled as the most vulnerable group to criminal events. In Sætnan et al.’s study, the operation of CCTV systems was found to be discriminatory, suggesting a ghettoization of spaces, which in fact hampers social interactions and economic investment and growth, breaks social cohesion and leads to more crime.
CCTV ineffectiveness vis-à-vis crime:
There are two sides to the argument over CCTV and crime detection and prevention. According to the Home Office research statistics the use of CCTV makes no significant difference whatsoever on crime rates in UK. Yet the Home Office itself has been promoting CCTV cameras as a major crime fighting tool. Research shows that only 14% of incidents caught using CCTV results in arrest. As a whole the installation of CCTV cameras may be a deterrent to crime but the statistics prove otherwise for individual isolated crimes. The purpose of CCTV surveillance is usually deterrence of, rather than intervention in, criminal acts. Many security cameras go unmonitored and are thus ineffective as a means of halting crimes in progress. This fact was forcefully demonstrated by a highly publicized juvenile murder case in England in 1992. After the discovery of the victim’s body and the apprehension of the perpetrators, police discovered that the initial abduction had been recorded by a shopping center’s security cameras. A 2008 Report by UK Police Chiefs concluded that only 3% of crimes were solved by CCTV. In London, a Metropolitan Police report showed that in 2008 only one crime was solved per 1000 cameras. In some cases CCTV cameras have become a target of attacks themselves. Research undertaken in Bradford, UK, adds to the case. Figures released by the police for car crime in the city’s car parks show that the highest levels of car crime occur in those car parks covered by the council’s CCTV systems. A 2013 Chicago Tribune opinion piece quoted a city spokesman as saying that surveillance cameras helped solve 4,500 crimes over four years, but the writer notes that more than a million are estimated to have taken place over that time period — meaning that the cameras’ contribution was 0.05% at best. The authors of a comprehensive Australian study stated that: “The effectiveness of CCTV as a crime prevention tool is questionable. From this research it appears CCTV is effective at detecting violent crime and/or may result in increased reporting as opposed to preventing any type of crime”.
Nine in Ten TFL CCTV cameras fail to solve a single crime:
Londoners are among the most surveyed people anywhere in the world, captured by cameras in nearly every aspect of their daily lives. Some reports have estimated that Britain is home to as many as 20% of the world’s total CCTV cameras. In November 2011 Transport for London (TFL) announced it was looking to spend between £20m and £60m on its CCTV capability. Research published by Big Brother Watch casts serious doubt on whether that investment will do anything to reduce crime or improve public safety. Figures obtained under the Freedom of Information act show how:
• TFL operates at least 82,826 CCTV cameras
• In the last twelve months, 6,972 police requests for footage were granted by TFL
• Accordingly, footage from 91.6% of cameras was not used by the police
This is hardly surprising, given it reflects previous academic studies into the use of CCTV. Indeed, the Metropolitan Police’s own research found how fewer than one crime was solved by every 1,000 cameras in the capital. Yet the British fondness for CCTV shows no sign of waning, despite a lack of any credible evidence existing that CCTV either deters or prevents crime. The significant resources being spent on surveillance are diverting money away from policing methods that could prevent crime and protect the public. CCTV is not a substitute for policing.
Police are failing to recover crucial CCTV footage, new figures of 2013 suggest:
The Metropolitan Police are failing to recover CCTV footage in almost nine out of ten burglaries and thefts allowing offenders to escape justice, new figures have suggested. British streets are among the most closely monitored in the world, with thousands of cameras providing round the clock surveillance. As well as acting as a deterrent, closed-circuit television cameras fixed on pubs, shops, offices and private homes, also provide an excellent investigative tool for catching criminals. But figures obtained under the Freedom of Information Act suggest the police are failing to recover potentially crucial footage in the overwhelming majority of cases involving acquisitive crimes, such as theft and burglary. CCTV is everywhere. For a number of reasons, the police just aren’t looking at this CCTV in around 85% of cases. As a result, criminals who could have been caught are not.
There are many studies that have found CCTV to be ineffective – below are a few:
|Title||Author(s)||Key Findings||Publication Date|
|Campbell Collaboration Report
‘Effects of Closed Circuit Television Surveillance on Crime
|Welsh & Farrington / Home Office||[…] the evaluations of CCTV schemes in city and town centers and public housing measured a much larger range of crime types and only a small number of studies involved other interventions. These CCTV schemes, as well as those focused on public transport, did not have a significant effect on crime.||2008|
|Why are fear and distrust spiraling in twenty-first century Britain||Anna Minton / Joseph Rowntree Foundation||mounting evidence shows that private security and CCTV does not reduce fear of crime or actual crime and might in fact increase crime||2008|
|The Cambridge evaluation of the effects of CCTV on crime||Farrington, Bennett & Welsh||the Cambridge evaluation is consistent with prior research in showing no significant desirable effect of CCTV on crime in city centers.||2007|
|No CCTV Interim Report on Cowley Road CCTV proposals||No CCTV||Surveillance cameras clearly present a serious threat to privacy and civil liberties and the alleged trade-offs of safety or security are unproven and vastly outweighed by the risk of creating a police state.||2007|
|National CCTV Strategy||Home Office / ACPO||Anecdotal evidence suggests that over 80% of the CCTV footage supplied to the police is far from ideal, especially if it is being used for primary identification or identities are unknown and identification is being sought, for instance, by media release.||2007|
|Data on London crime figures vs. number of cameras||Members of London Assembly||In 2007 members of the London Assembly obtained information under the Freedom of Information Act that showed CCTV has little effect on solving crime. The statistics show that more CCTV cameras does not lead to a better crime clear-up rate. In fact, four out of five of the boroughs with the most cameras have a record of solving crime that is below average At that time London had over 10,000 council/police run cameras.||2007|
|Assessing the impact of CCTV
Home Office Study 292
|Martin Gill / Home Office||It would be easy to conclude from the information presented in this report that CCTV is not effective: the majority of the schemes evaluated did not reduce crime and even where there was a reduction this was mostly not due to CCTV; nor did CCTV schemes make people feel safer, much less change their behaviour. Impulsive crimes (e.g. alcohol-related crimes) were less likely to be reduced than premeditated crime (e.g. theft of motor vehicles). Violence against the person rose and theft of motor vehicles fell in the target areas in accordance with national trends in recorded crime.||2005|
|Shoplifters on shoplifting
University of Leicester
|Hart, Gill, & Livingstone||One shoplifter articulated a perception shared by others, in that he had: “… never seen a camera jump off the wall and nick anyone.”||2003|
|National evaluation of CCTV: early findings on scheme implementation – effective practice guide||Scarman Centre National CCTV Evaluation Team||Given the current paucity of evidence as to the cost effectiveness of CCTV as a crime prevention mechanism, it is reasonable that partnerships have not provided a great deal of evidence on this subject.||2003|
|Home Office Research Study 252 – Crime prevention effects of closed circuit television: a systematic review||Welsh & Farrington||It was found that CCTV had no effect on violent crimes (from five studies)||2002|
|To CCTV or not to CCTV?||nacro||Three-quarters of the Home Office Crime Prevention budget was spent on CCTV between 1996 and 1998, yet a comprehensive review has revealed the overall reduction in crime was only five per cent. A parallel systematic review carried out by the Home Office that looked at street lighting, however, found a highly significant reduction in crime of 20 per cent.||2002|
|Towns on Television: Closed Circuit TV Systems in British Towns and Cities
Local Government Studies
|Graham, Brooks & Heery||CCTV may actually undermine the natural surveillance in towns and communities . . . the result may be a further spiral of social fragmentation and atomization, which leads to more alienation and even more crime.||1999|
|Effect of closed circuit television on urban violence
Violence Research Group, University of Wales, Cardiff
|Sivarajasingam & Shepherd||If there had been a significant deterrent effect as a result of CCTV installation then a decline in police detection of violence rather than the noted increase would have occurred. This study provides no evidence of a deterrent effect.||1999|
|Closed Circuit Television in public places: its acceptability and perceived effectiveness
Home Office Police Research Group
|Honess & Charman||page 25; “public acceptance is based on limited, and partly inaccurate knowledge of the functions and capabilities of CCTV systems in public places.”page 6: “a substantial number of respondents referred to television programs such as ‘CrimeWatch’ as a source of their information about CCTV.”||1992|
CCTV 90% Illegal and 80% Ineffective:
Whether CCTV is an existing element of your security/management strategy or you are considering investing in CCTV, you need to be sure that the system will provide unequivocal evidence. Imagine your frustration at having your CCTV evidence rejected in a health & safety claim or employment law dispute due to poor quality images or procedural mistakes. The financial impact of such cases could amount to tens if not hundreds of thousands of pounds, by comparison most instances of theft can appear almost inconsequential in terms of loss. The quality of images as seen on TV News and crime reporting programs is a damning indictment of CCTV standards. Consider the numbers quoted in the headline, 90% Illegal stated by CameraWatch is based on ‘initial research’ and refers to total or partial shortfall in Data Protection Act compliance in UK. 80% Ineffective refers to the efficacy of CCTV evidence examined by the Police and is stated in the Home Office National CCTV Strategy. These statistics are largely based on anecdotal evidence, nevertheless practical experience of those professionally involved in the assessment of CCTV systems would broadly agree with these estimates.
A British report on CCTV vs. street lighting:
It would be foolish to claim that well-planned CCTV can never have an impact, but the effectiveness of CCTV is often overstated. We have to ensure that CCTV is not favoured in place of cheaper and more effective measures such as adequate street lighting. Areas need to be appropriately policed, not remotely policed. It is time for a reassessment of the worth of CCTV in terms of is cost, both financial and in terms of privacy. The report confirms that the effectiveness of CCTV as a tool to fight crime is greatly overstated. While there may be situations where the use of CCTV has assisted in the detection of crime there is no evidence to support the argument that it prevents crime taking place. Indeed the report suggests that street lamps are far more effective way of deterring crime.
Does street lighting reduce crime?
The studies showed that improved street lighting had a positive effect in reducing crimes such as burglary and theft. It did not, however, reduce the incidence of violent crimes. When all data are considered together, improved street lighting was associated with a relative reduction in crime of 21 per cent in areas it was introduced, compared to similar areas where there were no such improvements. Perhaps surprisingly, the positive effects of improved street lighting are felt in the day–time as well as at night.
Why does it work?
There are two main explanations for why improving street lighting reduces crime.
1. By its very presence improved street lighting helps to increase surveillance, ‘guarding’ locations and deterring potential offenders. Better street lighting increases the risk of identification for offenders, it encourages more people to use public spaces, increasing the number of potential witnesses to any offence and making it less likely an offender can escape without being identified and later recognised.
2. Improved lighting signals investment in the community, increasing community pride and informal social control – and thus reversing the ‘broken windows’ effect. The broken windows hypothesis suggests that physical dilapidation in an area gives the impression that ‘nobody cares’ and thus no one will intervene against crime and disorder. Improving the environment displays ‘civic pride’ that demonstrates how much local people care about their locality. The installation of enhanced street lighting can make a location more welcoming
Criminal use of CCTV:
Criminals may use surveillance cameras to monitor the public. For example, a hidden camera at an ATM can capture people’s PINs as they are entered, without their knowledge. The devices are small enough not to be noticed, and are placed where they can monitor the keypad of the machine as people enter their PINs. Images may be transmitted wirelessly to the criminal.
CCTV, education and school:
Washington County Closed-Circuit Educational Television Project:
The Washington County Closed-Circuit Educational Television Project was the first closed-circuit television network in aiding elementary school teaching by the use of television programs.
CCTV in education as a teaching aid:
There are two categories of educational closed-circuit television, the total teaching and the visual aid.
Advantages of CCTV in education:
Benefits and Uses of CCTV Cameras in Schools:
CCTV in Classrooms:
There are a variety of situations in which CCTV cameras are used to provide surveillance, especially schools. Sometimes, in larger schools, providing security guards is not enough. It is not uncommon for some schools to install CCTV security systems in their premises to monitor and keep track of all the activities that take place. Sometimes, in larger schools, providing security guards is not enough for school security. This is usually done with complete awareness on the student’s, parent’s and teacher’s parts.
There are many benefits of using CCTV surveillance systems in schools:
-CCTV security systems help in preventing or identifying unauthorized intruders who enter the premises, thereby promoting school security.
-Keeping track of remote entrances and exits is easier through CCTV cameras.
-CCTV surveillance systems can keep track of housekeeping and ensure they are doing their work.
-CCTV security systems help organize exit in case of emergencies.
-School security measure to protect school property and identify perpetrators and vandals.
-CCTV surveillance systems help in the protection of staff vehicles.
-They keep track of teacher attendance and punctuality.
-CCTV cameras can help keep track of teacher’s attitude and methodology in teaching.
-CCTV cameras aid monitoring and preventing bullying amongst students.
-They help in ensuring discipline and punctuality amongst students.
-Prevent or track student thefts.
-Keep parents mind at ease about school security and environment.
CCTV surveillance systems in schools are a way of ensuring a safe, secure and healthy learning environment for children. Always consult with experts to work out the most strategic places to install CCTV cameras in your school.
In the United States and other places, CCTV may be installed in school to monitor visitors, track unacceptable student behavior and maintain a record of evidence in the event of a crime. There are some restrictions on installation, with cameras not being installed in an area where there is a “reasonable expectation of privacy”, such as bathrooms, gym locker areas and private offices (unless consent by the office occupant is given). Cameras are generally acceptable in hallways, parking lots, front offices where students, employees, and parents come and go, gymnasiums, cafeterias, supply rooms and classrooms. The installation of cameras in classrooms may be objected to by some teachers.
CCTV, traffic and transport safety:
CCTV and traffic monitoring:
Many cities and motorway networks have extensive traffic-monitoring systems, using closed-circuit television to detect congestion and notice accidents. Many of these cameras however, are owned by private companies and transmit data to drivers’ GPS systems. The UK Highways Agency has a publicly owned CCTV network of over 1,200 cameras covering the British motorway and trunk road network. These cameras are primarily used to monitor traffic conditions and are not used as speed cameras. With the addition of fixed cameras for the Active Traffic Management system, the number of cameras on the Highways Agency’s CCTV network is likely to increase significantly over the next few years. Other surveillance cameras serve as traffic enforcement cameras. Ever opened the mailbox to find a ticket for running a red light or speeding, even though you were never actually pulled over by police? That’s all thanks to closed circuit traffic monitoring systems. But while we all hear about the growing number of “red light cameras” popping up at busy and dangerous intersections, video surveillance isn’t just for issuing traffic tickets. With ever-increasing traffic volumes in metro areas, interstates and local roads have become far more congested, and reckless driving and accidents happen more frequently than ever. Many cities now mount surveillance cameras above busy roadways to monitor traffic flow, watch for aggressive or reckless driving, and examine the details of crashes and vehicle wrecks.
Area Traffic Control System (ATCS):
Using computerization and closed circuit television (CCTV) monitoring, ATCS allows traffic authorities and police to monitor and control traffic flows. Police can also capture on camera vehicles violating traffic laws, trace their police registration numbers and issue traffic summons. ATCS can control traffic from remote locations with officials working from central control rooms. The cameras installed are now able to capture cars breaking the law with high definition cameras, with additional capabilities for close up shots of both the driver and license plate. Loudspeakers installed at ATCS intersections will also allow direct communications with errant drivers.
Public Transport safety:
From trains and buses to subways and taxis, public transit is becoming ever more protected by CCTV, with surveillance cameras being installed not only in vehicles, but in stations and depots as well. Video monitoring helps to deter crimes against passengers, drivers and conductors, but also provides visual evidence for prosecution in the event that an individual is victimized or property is destroyed. For example, on a subway train, CCTV cameras may allow the operator to confirm that people are clear of doors before closing them and starting the train. Operators of an amusement park ride may use a CCTV system to observe that people are not endangered by starting the ride. A CCTV camera and dashboard monitor can make reversing a vehicle safer, if it allows the driver to observe objects or people not otherwise visible.
CCTV, industry and business:
Employers may install CCTV for various reasons including:
•Security: to prevent theft, violence and other crime.
•Health and safety: to check that health and safety rules are being complied with and/or so that footage is available in the event of a specific breach.
•Protecting business interests: e.g. to prevent misconduct.
•Assessing and improving productivity
•Compliance with legal and regulatory obligations: this is more likely in the financial services sector.
Industrial processes that take place under conditions dangerous for humans are today often supervised by CCTV. These are mainly processes in the chemical industry, the interior of reactors or facilities for manufacture of nuclear fuel. Special cameras for some of these purposes include line-scan cameras and thermographic cameras which allow operators to measure the temperature of the processes. The usage of CCTV in such processes is sometimes required by law.
Control of retail:
Some as software integrate with CCTV to monitor the actions of workers in retail environments. Every action is recorded as an information block with subtitles that explain the performed operation. This helps to track the actions of workers, especially when they are making critical financial transactions, such as correcting or cancelling of a sale, withdrawing money or altering personal information.
Actions which an employer may wish to monitor could include:
Each of these operations is transmitted with a description, allowing detailed monitoring of all actions of the operator. Some systems allow the user to search for a specific event by time of occurrence and text description, and perform statistical evaluation of operator behaviour. This allows the software to predict deviations from the standard workflow and record only anomalous behavior.
Corporate Uses for CCTV:
CCTV allows corporations and businesses to train, educate, and inform the workforce with ease. A training class led by one instructor can ensure that hundreds of employees are up to date on the latest techniques or requirements. Larger corporations with multiple locations, such as big box stores, often have CCTV systems in break rooms, which constantly run the latest information about the company and corporate culture. This kind of CCTV uses satellite to carry the signal instead of cable, but the concept is identical in nature. Security cameras also rely on CCTV to filter surveillance video to the appropriate viewers.
CCTV is one of the easiest ways for business owners to monitor employees and deter crimes in their establishments. Whether the place of business is a restaurant, office, bank or retail store, cameras placed in money-handling areas, back offices, storage rooms and sales floors can not only monitor employee access to these areas, but also help prevent theft, vandalism, and other forms of misconduct. Business surveillance is equally is important throughout off-hours as it is during business hours, since almost anything can happen overnight in an unoccupied facility. Security cameras not only provide evidence of theft, but also help owners and managers keep tabs on overnight cleaning and maintenance crews, to ensure that all required tasks are being carried out. CCTV systems are imperative for all businesses, whether you operate an office or own a local restaurant. They are one of the best ways to ensure commercial security for your business.
The Other Side of Using CCTV:
There are many far more interesting uses where imagination and flare can bring immediate and tangible benefits. So here I am looking at non-security applications for CCTV. Many of these applications were one off requirements, which for a purchased installation would have been impossibly expensive.
Recording the birth of a gorilla in a zoo at night:
Apparently gorillas are very private animals, particularly when expecting a birth. The BBC wildlife programme wanted to record the events leading up to and after the birth, but the problem was during the night when any illumination would be unacceptable. The solution was to use an infrared illuminator with an 850 nanometer filter which would be totally unobtrusive with an infrared sensitive camera and time lapse VCR. The result was the first recorded birth of a gorilla in captivity.
Making a wildlife program in an isolated area using a model helicopter:
Many exotic locations for wildlife filming are too remote or inaccessible to reach on foot or from conventional helicopters. One solution was to fit a miniature camera and radio transmitter to a small model helicopter. This was radio controlled and comparatively unobtrusive to the local wildlife, creating unique footage of film.
Reproducing the infrared vision of a goldfish:
A university was studying the ability of fish to apparently ‘see’ and navigate through murky water. The theory was that goldfish had vision that was sensitive to infra light. It would seem that where the visible part of the spectrum was largely reflected by water, infra light penetrates further. To simulate this, a camera was fitted with a filter that restricted its sensitivity to only the infrared part of the spectrum. An infrared illuminator was directed from above and the views from the camera noted. It was interesting to set up and different from run-of-the-mill CCTV.
Safety at Grand Prix racing:
After the tragic accident of Nicki Lauder at The Nurburg Ring in Germany, Grand Prix racing drivers banned the track for major events. In May 1994 a new Nurburg Ring was opened with a computer-designed track and many new safety measures. The particular item of interest is a Geutebruck system of cameras connected back to a video motion detection system in the control room. Each camera monitors an area of the track, with zones defined alongside the track. If a car leaves the track it is detected and a view of the area instantly displayed at the control room and the appropriate action can be set into motion. If it is an accident, emergency teams can be directed to the scene immediately; even saving seconds can make the difference between life and death. The system would also detect a spectator straying onto the trackside. If a car leaves the track and rejoins the race, the system is automatically reset.
There are many other examples of the innovative use of CCTV other than security, such as:
1. Production control in factories.
2. In a stage show to see obscured parts of a set.
3. Use at football stadia.
4. Arial photography from a hot air balloon.
Many of these applications require some lateral thinking and flexibility on the part of installation companies. Many of these systems have provided excellent value for money for the end user and can be very profitable for the installer.
Social, psychological and human aspects of CCTV:
CCTV and social control:
The rise of technological forms of social control has brought with it a dramatic shift in the nature of dealing with crime in society. A great deal of modern techniques of crime prevention are centered around the utilitarian principle of deterrence; as surveillance in the form of telephone tapping, interceptions of letters and emails and the electronic monitoring through CCTV camera systems gives the impression that the individual is under constant surveillance and therefore forces them to discipline themselves. Questions over the legitimacy of modern social control have arisen due to the fact that it tends to assert visions of order and justice on behalf of particular individuals or groups. Arguably the methods and the functioning of technological forms of social control as well as the ends serve to benefit particular social groups, as modern pervasive surveillance results in individuals aligning their own behaviour and actions in accordance with the social norms and patterns that are external to themselves. Individuals are forced to discipline their own behaviour and actions in accordance with that which is acceptable with social authority, asserting its presence through the omnipresent forms of technological social control. This correction of behaviour goes to benefit those in control of surveillance, especially considering the merger of public and private spheres in the development of surveillance. Furthermore as the political and economic elite in society have enlarged the scope of social control, this has subsequently led to the setting of social standards of behaviour and forms of etiquette that adhere to their own interests. This means that not only does modern social control marginalise and stigmatise certain social groups based on socio-economic inequalities; it also furthers the interests of society’s elite. This is due to the fact that it is a mechanism used to assert social standards, coercing individuals into certain forms of behaviour through an omnipresent threat which has an increasingly tightening grip on the decisions and actions of individuals. Powerful bureaucracies perform the task of collecting vast amounts of private information in both public and private spheres, together with technological advancements seen in the rise CCTV and the subsequent effect of forcing people to discipline themselves; this has resulted in the increasingly efficient forms of mass surveillance and control. Technological forms of social control assert particular views of order and justice to a great extent. From its conception, camera surveillance has been primarily used for the purpose of furthering the interests of the elite. With regard to this, as well as the way in which it consistently marginalises and stigmatises by targeting certain disadvantaged social groups, it arguably reveals that the views of order and justice that surveillance asserts are those of society’s elite. Individuals subject to constant and pervasive surveillance such as that in modern society are forced to discipline themselves as they are never sure when or if they are being watched, meaning they align their behaviour with that which is enforced by social control, even if it may work against their interests. Furthermore the extent of modern technological surveillance is often unbeknown to the individual, raising questions over the motives and the legitimacy of those in power managing social control. This presents the reality that not only does surveillance stigmatise and pervade privacy, but its increased efficiency leaves no room for the consideration of individual circumstances, treating people as a series of cases rather than unique individuals. This then means that the stifling regulation of the state enforced through surveillance creates a hostile and extremely impersonal environment towards the individual subject to its repression, by forcing them to act within a certain group’s idea order and justice.
CCTV: from social control to management tool:
Several countries have adopted CCTV video surveillance technology not as a measure for social control, but as a management tool to monitor and administer transport systems, rationalize the maintenance of building infrastructure and fire prevention, and for the management of social spaces. Countries like Switzerland have widely adopted CCTV technology as a tool for operational management of public areas.
Discrimination and social exclusion vis-à-vis CCTV:
As Norris and Armstrong have shown in their study of the operation of three CCTV control rooms, selection for targeted surveillance is, at the outset, differentiated by the classic sociological variables of age, race, and gender. Nine out of ten target surveillances were on men (93%), four out of ten on teenagers (39%) and three out of ten on black people (32%) Moreover, while displays of ‘suspicious behaviour’ played a part in determining who was surveilled, it was not the most important reason. From their study 36% of people who were subject to prolonged targeting, were surveilled for ‘no obvious reason’. Only one quarter (24%) of people were targeted for surveillance because of their behaviour but 34% of people were surveilled merely on the basis of belonging to a particular social or sub-cultural group. Unwarranted suspicion did not fall equally on all social groups. Two thirds (65%) of teenagers were surveilled for no obvious reason compared with only one in five (21%) of those aged over thirty. Similarly black people were twice as likely (68%) to be surveilled for ‘no obvious reason’ than whites (35%) and men three times (47%) more likely than women (16%). In short, the young, the male and the black were systematically and disproportionately targeted, not because of their involvement in crime or disorder, but for ‘no obvious reason’ and on the basis of categorical suspicion alone. As Norris and Armstrong concluded: As this differentiation is not based on objective behavioural and individualised criteria, but merely on being categorised as part of a particular social group such practices are discriminatory (Norris and Armstrong 1999:150). These British finding have been confirmed by studies in other parts of Europe. In the Netherlands, Dubbeld’s study of a railway CCTV control room described graphically the selective targeting practices of the operators: Operators had their own ways of categorising and classifying the objects of their surveillance. Operator identified suspicious individuals as ‘Naffers’ (short for North Africans, usually Moroccan or Turkish men) or called them ‘cockroachs’, ‘crazy pancakes’, ‘little rats’, ‘nazis’, ‘faggots’, annoying little men’, ‘mongols’, or ‘pancakes’ (Dubbeld 2004:121). In Milan, Fonio, on the basis of her observational study of a CCTV control room reported: In particular, North-Africans and East Europeans were tracked for no particular reasons but their appearance … Behavioral patterns did not play an important role in determining who had been monitored. Two social categories were also targeted on the basis of their appearances: young people, in particular those who were poorly dressed and nice-looking women (Fonio 2007:14). Thus, rather that promoting a democratic gaze, the reliance on categorical suspicion intensifies the surveillance of those already marginalized and increases, yet further, their chance of official stigmatisation. As von Hirsh and Shearing have noted, exclusion is frequently at the heart of situational crime prevention strategies and that is ‘now being extensively used in privately owned spaces that have public functions, such as shopping malls’ (von Hirsh and Shearing 2000:77). Wakefield’s study of an English mall with an extensive CCTV system found, over a five-week period, that 578 people were excluded and 65% of these exclusions involved ‘known offenders’ (Wakefield 2000:134:5) As McCahill reported in his study of the CCTV system in a North of England mall, it was anonymous groups of teenagers who were most likely to be targeted, deployed against and ejected; not because of any past or present legal infraction but because they were, in dress and demeanour, seen to be disrupting the commercial image of the mall (McCahill 2002). Similar results have been found in Lomell’s study of the operation of three CCTV systems in the Norwegian capital: Summing up, one can say that in Oslo, CCTV has had it most exclusionary effects in the most privatised of public spaces, where it is used mainly as a discriminatory tool ensuring marginalized people are kept out of site of consumers. Ejections were a substantial result of video surveillance operations at two of the sites namely the shopping mall and the transport center. In large part, these ejections were pre-emptive. That is to say, the majority of the exclusions were in response to appearances and categorical suspicions; only a minority of these ejections was in response to observed criminal or nuisance behaviours (Lomell 2004).
Are there Psychological Effects of CCTV?
For some people the use of CCTV in city centers does make them feel safer. For others there is the constant feeling of having their movements monitored. The adverse effects of CCTV monitoring for some people can be a constant feeling of paranoia, the feeling that an attack may occur. Many children who have had CCTV cameras placed in their school toilets would no longer use the facilities. According to the civil liberties group Big Brother Watch the UK is now raising a generation of children that are accustomed to being constantly monitored.
Human side of CCTV:
We tend to look at CCTV as a detection tool, but there’s no real detection going on. In reality, today’s CCTV systems still rely on their human operators. And humans are… only human. But it is possible to improve operator surveillance by recognising and playing to the limitations of human biology. Active surveillance is an intellectually demanding task. It requires you to sit behind a screen and focus intensely. Really, 30 to 40 minutes is the maximum you can monitor effectively what’s going on in a very complex environment. For dedicated surveillance, operators can really only focus on between 1 to 2 monitors at a time. A good operator must also have the ability to differentiate between colours, pick up on motion and speed, recognise patterns and anomalies, and have a good memory. They must also have good observation skills, including the ability to scan, focus, and make use of their peripheral vision, and have access to good intelligence information. A good operator who understands what’s going on in the environment can detect individuals who are preparing to commit crimes, intervene and prevent the crime from being committed. You might have an operator in a control room with a couple of hundred cameras. They could have up to 20 or more screens to monitor. They could also be manning a phone and other things. In this case they are not necessarily going to see the subtle behaviours that will alert them to an incident starting to emerge.
Is manned guarding or CCTV more effective?
Some companies are asking themselves whether it is more economical and efficient to choose a CCTV over manned guarding. CCTV is a vital part of any security system and should definitely be included in your budget; however, there are certain things that CCTV cameras are unable to accomplish, like covering those blind spots. Using a manned system has many advantages over CCTV. CCTV lacks a personal touch and is unable to use judgement in situations. A human is able to pick out which situations and events they fell are threatening of suspicious whereas a camera is unable to do this. With a manned guarding system in place, you can be assured that whether or not you have a CCTV system on site, the human touch can maximize the effective functionality of any equipment that you may choose to operate in your establishment. If you ensure you have a good manned guarding system in place you can be safe in the knowledge that your building will be protected twenty four hours a day. Due to the fact a guard is able to see immediately what the trouble is they are more likely to act upon it straight away which is not the case with CCTV. In order to prevent accidents and any other possible threats, the security guard is constantly monitoring the security cameras themselves. By using both methods, you ensure that you establishment has maximum protection. Unlike CCTV people have emotions which means that they are more likely to do a better job for you because they care about what they are doing You must be aware though that people do occasionally make mistakes. By ensuring you have employed a good mix of reliable people you will probably find they won’t let you down because they want to get paid! Additionally if you employ people with a previous background in the security sector they will be able to assist you with other security related issues. One of the main reasons for choosing manned guarding is the fact that security guards are human beings. There is usually a tough training process involved in becoming a security guard. Security guards have other skills such as communication and the ability to fill out paperwork which gives them another advantage over cameras.
Only a few years ago, specialist consultants in CCTV were a rare breed and often associated with installation companies who cannot give independent and unbiased advice. Now there are quite a number of consultants offering independent advice on many aspects of CCTV.
What are the benefits of employing an independent CCTV consultant?
One of the most important reasons for using the services of a consultant is to receive completely unbiased and objective advice. Most installing companies have preferred products for very sensible commercial reasons. It is natural therefore that they should present these in the best possible light. It can be very difficult for a customer to differentiate between the claims of competing salespeople.
Serving your interest:
A professional consultant is employed by you and has no incentive to promote any particular product or system. Most consultants keep up to date on the performance of various products through experience with installations and trouble shooting. Not all products that appear equal to the layperson are necessarily so, the consultant can steer you away from products with a poor track record for performance or reliability. The pressure on the customer to differentiate between competing proposals is eliminated.
Saving your time:
Most business people these days have little enough time to spare and will be directing their efforts into running and sometimes, the survival of their company.
Saving you money:
Most people have had experience of the wide variations in price between competing quotations for apparently the same specification. Unlike the purchase of machines or standard products, CCTV or access control systems are likely to be a new venture by many companies and local authorities. They simply cannot be expected to have the experience and detailed knowledge on which to judge differing proposals.
Peace of mind:
Technology moves rapidly ahead these days, with many ways of increasing the effectiveness of both new and existing systems. Multiplex recording, video transmission, colour cameras, detection of movement, etc. are all very much more advanced than only one year ago. Even so, products with apparently similar specifications to the layperson can differ dramatically in actual performance under particular circumstances. This is especially true today in the case of digital recording and so called digital cameras. Here again, objective advice can be invaluable in the selection of the right equipment for the job.
CCTV, laws and privacy:
The need for video surveillance has grown in this technologically driven era as a mode of law enforcement. Video Surveillance is very useful to governments and law enforcement to maintain social control, recognize and monitor threats, and prevent/investigate criminal activity. In this regard it is pertinent to highlight that not only are governments using this system, but residential communities in certain areas are also using this system to create a safer environment. However, this move is fundamentally opposed by many civil rights and privacy groups across different jurisdictions and have expressed concern that by allowing continual increases in government surveillance of citizens that we will end up in a mass surveillance society, with extremely limited, or non-existent political and/or personal freedoms. We have now moved into an age where security seems to be the primary issue for most countries and their citizens. Video surveillance is increasingly being used to assuage the fears of the citizens and bring perpetrators to justice. In such a scenario, the issue of privacy rights of individuals seems to have taken a backseat. While some countries such as Canada and Britain have attempted to strike a balance between the need for surveillance and the privacy rights of the people, other countries such as the United States of America and Japan do not seem to have made much progress in terms of creating video surveillance norms or regulations to protect the privacy rights of citizens. Considering the pressing need for video surveillance to address national security issues, India surprisingly has no laws on the same. In this regard, India needs to draw from the experience of the United Kingdom and Canada. The first step is to enact laws permitting video surveillance. These laws should be tightly worded and strictly connoted, considering the encroachment on civil liberties. Further, in order to balance security with privacy, the next step is to create an office for the information commissioner. It should be created and powers should be conferred to ensure that the privacy related disputes are handled efficiently and expeditiously. Furthermore, the misuse of the powers conferred upon surveillance authorities should be deterred by giving further powers to the commissioner to impose pecuniary liability.
A 1978 survey on the topic of CCTV in the workplace found that 77% of employers interviewed supported the use of CCTV on the job. However, it also found that a majority of employees felt that CCTV in the workplace constituted an unwarranted intrusion, and favored the passage of laws prohibiting such surveillance. Ironically, the ascendancy of more sophisticated electronic employee surveillance technologies such as keystroke monitoring of information workers has rendered CCTV somewhat obsolete as a visual management technology.
The Data Protection Act (DPA) 1998 in the United Kingdom led to legal restrictions on the uses of CCTV recordings, and also mandated their registration with the Data Protection Agency. In 2004, the successor to the Data Protection Agency, the Information Commissioner’s Office clarified that this required registration of all CCTV systems with the Commissioner, and prompt deletion of archived recordings. However, subsequent case law (Durant vs. FSA) limited the scope of the protection provided by this law, and not all CCTV systems are currently regulated. However, private sector personnel in the UK who operate or monitor CCTV devices or systems are considered security guards and have been made subject to state licensing. The UK Home Office published a code of practice in 2013 for the use of surveillance cameras by government and local authorities. The aim of the code is to help ensure their use is “characterized as surveillance by consent, and such consent on the part of the community must be informed consent and not assumed by a system operator. Surveillance by consent should be regarded as analogous to policing by consent.” Under the law, all public surveillance cameras must be registered with the Information Commissioner, and the following conditions must be met:
• An appropriately sized (at least A4) sign must be present to indicate the presence of a camera.
• The sign must state the purpose of the camera system.
• Information captured should only be used for its intended purpose.
• Cameras should be placed to avoid capturing irrelevant or invasive images.
• Individuals have a right to a copy of any data held about them.
Request CCTV footage of yourself in UK as per DPA:
You have the right to request closed circuit television (CCTV) footage of yourself. The CCTV owner must provide this within 40 days, and can charge up to £10. You need to make a request in writing to the owner of the CCTV system. The owner’s details are usually written on a sign attached to the camera, unless the owner is obvious (like a shop). You should tell them you’re requesting information held about you under the Data Protection Act, and provide information to help them identify you, like:
•a specific date and time
•proof of your identity
•a description of yourself
The CCTV owner decides how they provide the footage, and can edit it to protect the identities of other people. The CCTV owner can invite you to a viewing of the footage, but only if they’re unable to provide you with the footage itself.
They can refuse your request if:
•the footage has other people in it
•it would put a criminal investigation at risk
CCTV footage of a crime:
If the CCTV footage relates to a crime and the police have the footage, they will tell you if you can see it.
Can I give the footage to anyone else?
Giving camera surveillance footage to a third party outside the agency who does not already know it (and is not in a position to find it out) is called a ‘disclosure’. The privacy principles have rules about when you can disclose personal information. Some of the circumstances in which you would be able to disclose footage containing personal information include:
•If the individual captured by the camera was reasonably made aware this would occur (for example, there was a collection notice posted near the camera that said the disclosure would occur)
•If the disclosure is authorised or required by law
•If satisfied on reasonable grounds that the disclosure is necessary for a law enforcement activity being carried out by a law enforcement agency or to prevent or lessen a serious threat to an individual or the public.
Legal issues vis-à-vis CCTV:
Admissibility of Digital Images as Evidence:
A common misconception in the surveillance and monitoring industry is that digital images are inadmissible as evidence in court. The truth is that digital images are admissible as evidence in courts, provided that the digital images are appropriately authenticated. It is the ease with which digital images can be processed, or are processed before being recorded in memory, which has caused some in the surveillance and monitoring industry to doubt whether or not digital images are admissible as evidence in court. The compression of digital images is actually quite a procedurally straightforward (if mathematically complex and intensive) exercise. The second concern which some in the surveillance and monitoring industry have regarding the admissibility of digital images as evidence in court relates to the ease with which a digital image can be processed. Digital images are usually stored in binary format in computer memory. This generally means that they can be processed just like any other computer data. Indeed many modern films rely on such processing in order to achieve dramatic cinematic effects and most newspapers now use digital processing techniques to touch-up photographs or to create montages. Therefore digital images like other types of evidence, require to be appropriately authenticated. What is meant by authentication in this context? For these purposes, authentication is the process of convincing the court that a document (which would include a digital image) is what it purports to be: of proving the origin of the image and that it has not subsequently been altered (or, where alteration has occurred, proving the nature of the alteration). Such alteration could include, for example, image enhancement or image manipulation. There are the technical methods by which digital images may be authenticated including, for example, by watermarking, by encryption or by digital signature. In event of doubt, the court may seek opinion of forensic laboratory to know whether digital image/video is doctored or not using science of digital forensics. In India, all electronic records are now considered to be documents, thus making them primary evidence. Increasingly, incidents or crimes are being captured and recorded on CCTV recorders. Such recordings are accepted by the courts as being real evidence. In order to use video/tape recordings as evidence, the prosecution must prove that the tape or video recording is authentic or genuine. The prosecution must explain how and why the recording was made and who had control of the recording afterwards. The defense may object on these grounds and it will then be a matter for the judge to decide whether or not to allow the recording to be put to the jury. In around 70% of all cases, CCTV footage is found to be inadmissible as evidence in a Court of Law because the quality of the evidence is considered inadequate. This can result from the poor design and bad installation of the system and highlights the importance to seek professional advice from the outset.
Problems with using CCTV Evidence in Court:
Photographic or video evidence is often seen as infallible – either damning or exonerating suspects. However, it can have its problems. There are many different types of CCTV cameras and image quality can vary greatly. Some cameras record still frames at intermittent times; for example, they may take a photo every second or half-second which can miss vital parts of an incident. Many cameras still record in black and white, and most do not record sound – which can present problems of its own. Poor quality images can be problematic from the perspective of both the defense and prosecution. From a prosecution point of view, cameras that take pictures at intermittent times may fail to pick up an offending act e.g. a punch or kick. The defense will often be able to rely upon this omission to establish ‘reasonable doubt’ regarding the commission of the act. From a defense perspective, such footage may omit defensive movements by the defendant or aggressive actions by the complainant. Furthermore, prosecutors will sometimes engage expensive experts to identify suspects from blurry footage using facial and body mapping techniques. Such ‘expert evidence’ may be difficult to overcome, especially if a defendant cannot afford the extra thousands of dollars for a report of their own. And how accurate can ‘facial mapping’ really be if the image is poor or the person featured is wearing a disguise? Some say that such ‘expert opinions’ are just as prone to error as traditional eye witness testimony. In Scotland, William Mills was wrongfully convicted on the basis of CCTV images which showed a man wearing sunglasses and a scarf over his mouth. Police identified Mills as the man in the video, and eye witnesses picked him out during an identity parade. Mills was found guilty despite continuing to proclaim his innocence and declaring he had lost faith in the justice system. But he was ultimately released when it was found that he was not the bank robber at all. This is just one example of the problems with identification evidence – whether by way of CCTV footage, eye-witness testimony or facial mapping.
Recognition standard of CCTV:
So if you are using the PAL (analog) system and wish to identify an Unknown Person they need to be 100% of screen height and to recognise a Known Person then must be a minimum of 50% of the height of the screen. However if you have a recorder that produces pictures in 4CIF or D1 (digital), because the resolution is better than PAL, to identify an Unknown Person they only need to be 70% of screen height and to recognize a Known Person they must be a minimum of 35% of the height of the screen. The Home Office Operational Requirements Manual for CCTV states that while recording one picture per second per camera is adequate where there is little activity, 6 to 12 pictures per second per camera should be recorded where there is busy activity such as doorways. Home Office guidelines recommend a minimum 120% size image for identification by CCTV to be permissible in court – this means that you should provide a view (of at least) from the head to the knees to outwit the arguments of a sharp barrister.
CCTV and privacy:
The House of Lords (UK) have expressed their view that privacy is an “essential prerequisite to the exercise of individual freedom”. We can no longer say that we live private lives when every move is being watched by CCTV cameras. Such surveillance renders our society as equivalent to a large scale big brother. Our every move can be traced and information can be gathered about our daily activities. If this information were to be misplaced, which central government seems to do frequently, then who knows what other breaches our freedoms will endure. The use of CCTV can be an invasion of privacy. The cameras are capable of recording innocent people going about their daily activities. Under the Human Rights Act 1988 the use of CCTV in certain circumstances can be seen as an infringement on privacy. An individual who installs a CCTV camera that points on their neighbour’s property can be infringing on the neighbour’s right to privacy. CCTV cameras installed in the home should be used for home security only.
Everyone has the right to respect for his private and family life, his home and his correspondence. The right to privacy protects you against unnecessary and heavy-handed state surveillance and intrusion into your personal life. The right to privacy can only be limited by law when it is necessary to do so in a democratic society for reasons such as national security, public safety, the prevention of crime or protection of the rights and freedoms of others. Any limitation on this right must be proportionate. The importance of the right to personal privacy becomes self-evident in the immediate aftermath of the horrors of the Second World War. The right to a private life is based on principles of human dignity and is inherently linked to many other rights such as equal treatment and free expression. A society that does not pay proper regard to personal privacy is one where dignity, autonomy and trust are fatally undermined.
Human Rights and the Use of CCTV:
Article 8 of the European Convention on Human Rights concerns the right to family and private life. This includes the right to respect for an individual’s home and correspondence. The right contained in Article 8 is known as a qualified right which means that there may be circumstances in which some interference with it is justifiable. This right means that an individual has the right to the level of personal privacy which is compatible with a democratic society, taking into account the equivalent rights and freedoms of others. Any interference with this right by a public authority may be subject to a test of acceptability. The state and public authorities are permitted to interfere with an individual’s Article 8 right to privacy if the interference has an obvious legal justification. Amongst other reasons, this could be because the interference is necessary to protect national security or for the prevention of crime. In addition to having a clear legal justification, the amount of interference with the right must be proportionate to the end result achieved and only go as far as is required to achieve that result. Public authorities, including the police and local councils, must balance the benefits of using CCTV against an individual’s right to privacy.
As the use of cameras and video recorders becomes more common, society at large is becoming concerned about privacy issues related to cameras and other security surveillance devices. Many people feel that cameras, especially hidden ones, are a threat to their right of privacy. Security professionals and facility managers who use cameras and other surveillance devices need to understand the legal implications of installing such devices. In today’s litigious environment, people who feel that their privacy was invaded are likely to sue, particularly if your company is a well-established company with “deep pockets”. The improper use of surveillance devices may also subject your company and its managers to prosecution for violation of federal or state laws.
Here are a number of things to consider prior to installing any type of camera or other surveillance device:
•Camera surveillance and video recording in “public” spaces is usually legal.
•Camera surveillance and video recording in “private” spaces is usually not legal. A private space is a space where a reasonable person would have an “expectation of privacy”. Areas where an “expectation of privacy” exists include restrooms, showers, dressing rooms, lockers rooms, employee lounges, first aid rooms, and other similar spaces.
•The laws relating to the recording of audio are usually much stricter than the laws relating to the recording of video. Despite the fact that most video recorders allow the recording of audio as well as video, the use of the audio recording feature is illegal in many applications.
•Some jurisdictions may require that a sign be posted giving notice that the area is under video or audio surveillance.
•Cameras that observe employee work areas are usually legal, but can create morale problems if employees feel that the cameras are being used to track their productivity and work habits. The coverage and purpose of cameras and other surveillance devices should be clearly communicated to all employees. It is suggested that this topic be included in the company employee handbook.
•Companies who have employees represented by a union or other trade organization should verify that the installation of cameras or other surveillance devices does not violate the terms of any collective bargaining agreement.
•Be especially careful with hidden or “covert” camera installations. While it may be tempting to try and catch a thief, an improperly obtained recording is useless as evidence and may subject the company to legal damages costing far more than any theft ever would. The use of covert cameras in theft investigations is not a “do-it-yourself” project and is best left to skilled investigators who are familiar with the applicable laws. Check the laws concerning audio and video surveillance applicable in your country or province. The proposed use of cameras (particularly covert cameras) in questionable areas should be reviewed by your attorney prior to installation.
Despite its usefulness, the use of CCTV surveillance is not without controversy. CCTVs can be regarded as some to be an invasion of one’s privacy. For instance, if they are installed thoughtlessly at say someone else’s bedroom or bathroom, it will indeed be an intrusive act. CCTVs should also not capture part or all of the properties of one’s neighbour since this may constitute an act of voyeurism or harassment. Some employers, with the intention of making sure their staffs do not waste time on the job (e.g. surfing the Internet and chatting) or steal from them, install CCTVs to monitor them. The employees may feel offended if they hold the view that their employers are spying on them. Mistrust and hostility may result as constant monitoring puts workers ill at ease. Employees must be notified of the installation should the employer wishes to do so. Therefore, it is of paramount importance to understand the rationale behind the need to install a CCTV and the location at which this is done so as not to be perceived as a personal intrusion of one’s privacy. It is an abuse of CCTVs when they are used to observe someone’s behaviour or to obtain personal information. Users must exercise responsibility and should not distribute footage to unauthorised personnel or make it public. Essentially, they should only target specific areas that have specific problems to be solved. There should be provisions for sanctions/ punishments for any abuse of CCTVs and remedies/ protection for those harmed by its misuse.
Opponents of CCTV point out the loss of privacy of people under surveillance, and the negative impact of surveillance on civil liberties. Furthermore, they argue that CCTV displaces crime, rather than reducing it. Proponents of CCTV cameras have argued that the cameras are not intruding into people’s privacy, as they are not surveilling private, but public space, where an individual’s right to privacy can reasonably be weighed against the benefits of surveillance. However, anti-surveillance activists have held that there is a right to privacy in public areas. Furthermore, while it is true that there may be scenarios wherein a person’s right to public privacy can be both reasonably and justifiably compromised, some scholars have argued that such situations are so rare as to not sufficiently warrant the frequent compromising of public privacy rights that occurs in regions with widespread CCTV surveillance. Widespread CCTV surveillance violates citizens’ rights to privacy and anonymity within the public sphere by jeopardizing both their liberty and dignity and therefore CCTV surveillance should be reserved for specific circumstances in which there are clear and reasonably demonstrated benefits to its implementation and few ethical compromises.
Privacy and ethics vis-à-vis CCTV:
According to the 2006 Privacy International Report, government’s policy initiatives on security are ‘destabilizing core elements of personal privacy’. Therefore, there must be an understanding on how changes in privacy laws vis-à-vis CCTV technology affect legal and constitutional protections, individual rights, freedoms and democratic institutions. The use of CCTV technology has stirred ethical concerns. These concerns refer to the lack of privacy protection, the repression of individual liberties for the ‘greater good’ and mounting fears of insecurity. They have stimulated the rise of rules and regulations which aim to protect individuals’ rights and freedoms as well as regulate the use and output of information captured by such systems. Politicians who abide by CCTV as an effective and successful method in the field of crime prevention, suggest that the presence of CCTV systems in public spaces act as a deterrence to criminals or potential offenders. Therefore, innocent individuals should not be bothered by its presence. The cameras target offenders and thus offer no harm to the general public. This mentality is widely used to convince the public that CCTV systems are used for a specific reason and do not impinge on issues of privacy or civil liberties. This mentality in fact poses an ethical concern, which assumes that in general individuals are innocent and must give up some liberties for the ‘greater good’ (to detect the ‘rotten apples in society’). For many, this entails a repression of rights and freedoms in the name of an ineffective method (Bach 2008). In several countries, the public has expressed concern over the issue of how improvements in technology (increasing places under surveillance) are detrimental to the protection of privacy and personal data (Ruegg et al. 2004). France’s Commission national de l’informatique et des libertés (CNIL) warns of the dangers of CCTV of taking away freedoms of individuals (Guibert and Langellier 2007). In this case, there is also an absence of structures of accountability when it comes to controlling, monitoring and assessing information from CCTV systems. Fay (2004) suggests that there is a concern that authorities and operators of CCTV systems may abuse it for personal or collective interests: bribing, entertainment, court cases, etc. Another ethical issue surrounding CCTV is its role in the increasing exclusion and discrimination of certain groups and individuals. Stephen Graham (2002) refers to ‘exclusionary and inclusionary’ powers, which lead to social boundaries or the exclusion of certain groups in society which are deemed as ‘disruptive’ to social order. This situation results in unfair targeting of groups and stigmatization. Honess and Charman found that video surveillance controllers were overscrutinizing young black males, and ‘scruffy people’ without due cause. CCTV imposes stereotypical expectations, guilty by association charges and misinterpreted innocent actions. A study conducted in Oslo, Norway revealed that citizens articulated a concern about video surveillance controllers targeting ‘scruffies’ for no obvious reason, which causes marginalization. Stephen Graham (2002) says that these outcomes reflect a dangerous level of power given to “automated, algorithmic and invisible systems of social control” which can cause more harm than good to certain individuals. Klauser (2004) discusses the impact on spaces and interactions: “video surveillance is changing the territoriality of public space users”. In other words, CCTV is restructuring the urban landscape as places of consumption, whereby private management systems are taking over and controlling public spaces as well as social, political, economic and spatial processes. Fay (1998) says that dominating consumption landscapes are the reason for installing CCTV technology. In this case, the reasons are ‘egotistical’ and entail economic benefit to retailers in urban settings. The outcome is that individuals are stigmatized and excluded from certain public spaces due to their geographical location, ethnicity and social status for the sake of capitalistic motives.
Women commuters raise privacy issues, delay CCTV installations in local trains in Mumbai:
The decision to install close-circuit television cameras (CCTV) in Mumbai’s local trains has now been delayed further as women commuters have raised privacy issues and the railways are now reworking on the proposal to install them on train’s corridors and passages and not near the seating area. A section of women commuter associations in Mumbai have a different view on the matter. According to them CCTVs must be installed in all corners of the trains. “When one is travelling by public transport, there is nothing like privacy. Safety should be utmost priority. There have been big fights and crimes in trains and in case someone dies, the cameras will be an important evidence in nailing the criminal,” Vandana Sonawane, commuter activist said.
Neighbourhood watch: how domestic CCTV is sweeping the UK:
Many UK homes are now bristling with CCTV cameras, sometimes causing bitter disputes between neighbours. “We get a lot of submissions from the public with regard to problems they are having with their neighbours’ CCTV,” says Peter Fry, director of the CCTV User Group. Fry’s organisation primarily concerns itself with CCTV use by local authorities and companies, but in the absence of a domestic equivalent they are getting an ever-increasing number of complaints about domestic use. “The problems are many and varied,” says Fry. “There are accusations of paedophilia if cameras are pointed into gardens where children play; there are issues of harassment, and concerns about people using zoom lenses. When people raise these issues with me, I usually suggest they take it up with the police.” He says the rules are confused and need clarification, but that, even though there is no specific law covering domestic CCTV, it may still be deemed to constitute harassment, and the courts may be willing to issue an asbo against the camera user.
A 2010 document from the European Forum for Urban Security, “Charter for a Democratic Use of Video-Surveillance” provides a useful overview of the issues at stake as well as a set of principles and tools to ensure that citizens’ rights are respected with CCTV systems. These include:
•Necessity: The use of camera systems must be justified empirically, ideally by an independent authority. Objectives and intended outcomes must be defined.
•Proportionality: CCTV equipment must be appropriate for the problem it is intended to address. Technology should “respond to the established objectives, without going further.” Data should be protected and the length of time it is retained be clearly defined.
•Transparency: Citizens should know what the objectives of a CCTV system are, what its installation and operational costs are, the areas being surveyed, and what the results are. Reports should occur regularly so citizens can make informed decisions.
•Accountability: Those in charge of public CCTV systems should be clearly identified and accountable to the public, whether the systems are run by the government or private firms.
•Independent oversight: An external body should be charged with ensuring that systems respect the public’s rights and are achieving their stated objectives. Ideally citizens would have a voice in the oversight process.
The world should follow British model for CCTV use:
CCTV pros and cons:
CCTV cameras have the potential of creating unintended effects, good and bad. The “halo effect” refers to the potential for greater security in areas outside the view of cameras; this could be offset by the “displacement effect,” which pushes antisocial activity to other parts of the city. Cameras could also promote a false sense of security and lead citizens to take fewer precautions, or they could also cause more crimes to be reported, and thus lead to a perceived increase in crime. CCTV footage is frequently too poor to identify anything useful; police are often too slow to collect CCTV (by which time the footage has been wiped); or, in cases where people allege misconduct by the authorities, footage has sometimes mysteriously disappeared. If criminals are wearing masks or have their faces obscured while being recorded on CCTV cameras, there may be very little that the police can do to successfully identify them if there isn’t more useful information to use. And as with the 2013 revelations of widespread data collection by the U.S. National Security Administration, the indiscriminate gathering of information on law-abiding citizens, however well-intentioned, has the potential for misuse. The Washington Post reported in February 2014 that new aerial video surveillance technologies are being deployed that can monitor virtually everything in an area the size of a small city.
CCTV does have weaknesses—some technical, and some related to camera placement and monitoring. First, systems that are cheaply made or improperly installed have limited value. Cameras can be vandalized or disabled, and standard cameras do not capture images well under poor lighting conditions, although newer technology can compensate for this. Hackers and guerilla artists have exposed the vulnerabilities of the video systems in an act dubbed “video sniffing”, they have crossed feeds, uploaded their own video feeds and used the video footage for artistic purposes. Second, CCTV works best in areas with open and plain layouts. Complex areas and layouts make a high degree of camera coverage difficult to obtain. Third, when cameras are used for surveillance, fatigue—both physical and mental— can affect the performance of staff watching the monitors. Finally, some critics maintain that the cameras mainly record minor offenses, such as public urination, graffiti, and vandalism. On the other hand, the growth in CCTV installations demonstrates a general consensus that the presence of cameras seems to deter crime. Moreover, so far no one has been able to prove definitively that the use of cameras in one area displaces crime to neighboring areas.
Apart from their numerous strengths, CCTV Cameras may be disadvantageous when it comes to personal privacy, too. Homeowners who’ve got CCTV camera systems set up in their own homes are going to be monitored 24/7. They won’t have the capacity to perform what they wish to do because they are being watched every single second, every single minute, every single day. Getting several CCTV Cameras and installing the best CCTV cameras at home can certainly help protect against as well as discourage crooks and also intruders. Yet, you’re also limited from performing a lot of things without restraint.
Advantages of CCTV:
There are many benefits of using a CCTV security system. Some are obvious, others less so. The most common benefits that get reported to us are:
1. Increased deterrent – CCTV systems are a great deterrent to potential thieves. Once they realize that your home or business is protected by a closed circuit television system they invariably choose to go somewhere else.
2. Safer working environment – CCTV helps to ensure adherence to health and safety policies and can be invaluable in staff training.
3. Reduced retail theft – shop lifters deliberately target businesses with poor security and will think twice if there is an increased risk they may be caught on camera.
4. Increased detection – the prosecution rates for businesses / home owners using CCTV is many times higher than that for those without CCTV. If you are unfortunate enough to be a victim of crime at least there will be a strong chance of detection and conviction.
5. Eliminate fraudulent insurance claims – in an increasingly litigious society is has never been more important to protect your business against claims that are not legitimate. CCTV can eliminate this and reduce your premiums.
6. Remote monitoring – keep an eye on your home or business when you aren’t there. CCTV systems can be viewed and controlled remotely over the internet (via an iPhone, laptop etc).
7. Reduced fear of crime – knowing you are well protected gives a feeling of security that should not be underestimated.
8. Receive warnings in advance – CCTV systems can alert you of any suspicious activity (via text or email), enabling you to view what’s happening and if necessary notify the police before a crime has been committed.
9. Increased professionalism – CCTV is an excellent staff training tool.
10. Staff protection – CCTV is perfect for preventing assaults and false claims of misconduct (ideal for schools, hospitals etc).
11. CCTV today often supervises industrial processes that take place under conditions too dangerous for humans.
12. Many cities and motorway networks have extensive traffic-monitoring systems, using closed-circuit television to detect congestion and notice accidents.
13. Monitoring the situation at home : maid, children, sick family members etc.
Disadvantages of CCTV:
1. Encourage complacency:
Security cameras should be one part of a more comprehensive business security system complete with alarms, electronic access control panels and environmental hazard detectors (smoke alarms, carbon monoxide detectors and sprinkler systems). You need additional security measures to ensure complete protection for your business.
2. Can’t stop robberies in progress:
Cameras capture footage so you can receive justice in court, but they can’t stop a robbery in action. They don’t alert police like an alarm system does. That means, even with the perpetrator behind bars, you’ll still have intangible losses to deal with, such as the goodwill lost when customers no longer feel safe, and the time wasted in court, making insurance claims and reordering stolen inventory.
3. Can be useless in police investigations:
Most thieves will do everything they can to hide their identity while doing a misdeed. If the perpetrator is masked and hooded, the footage picked up by a security camera can prove worthless in an investigation.
4. CCTV does not reduce crime:
A recent study by the Scottish Centre for Criminology shows that virtually all claims of crime prevention are false. Crimes of passion, crimes involving drugs and alcohol, and actions by professional criminals are not prevented by the cameras. One study by Brighton University’s Health and Social Policy Research Centre flatly concluded that there is no evidence they are having any deterrent effect on criminals. In fact, the report says the incidence of violence and disorder in the areas covered by the cameras is on the increase. In many instances the cameras have made the streets a more dangerous place. Cameras might make some people feel safe but the vast majority of crimes committed within the range of cameras are not detected. The cameras are often looking in a different direction, are not functioning, or are unable to recognise a crime being commissioned. Criminals have eyes too, and they know which direction a camera is facing.
5. CCTV is misused as replacement of policing:
Across Britain, CCTV is being used to engineer a fundamental change to policing practice. Instead of police being there, on the street, to prevent crime, they are reacting to acts that appear on a screen. While the occasional well publicised interception may occur, most criminals have escaped long before the police arrive. Many small towns have installed CCTV only to find their police numbers are immediately reduced. Hardware is being used to replace community spirit and traditional community policing. And while the police retreat further and further from the people they are supposed to protect, we become more vulnerable to crime.
6. CCTV is a tool to enforce morality and public order:
Originally installed to deter burglary, assault and car theft, in practice most camera systems have been used to combat ”anti-social behaviour,” including littering, urinating in parks, underage smoking, traffic violations, graffiti, fighting, obstruction, drunkenness, indecency, and evading meters in town parking lots. The majority of so called “detections” by cameras are of this nature. CCTV is also used by authorities to track the movement of individuals “of interest”, and to monitor public meetings, marches and demonstrations.
7. CCTV is a honey pot for perverts:
There is a rapidly growing body of evidence that CCTV is being abused. The recent commercial distribution of the “Caught in The Act” video involving people in a variety of intimate situations created widespread anxiety. One camera operator in Mid Glamorgan has been convicted on more than 200 counts of using cameras to spy on women, and then making obscene phone calls to them from the control room. The prestigious magazine New Scientist reports that one leisure centre has placed cameras in a women’s changing room. The images are monitored by men.
8. CCTV is a tool for prejudice and discrimination:
In many instances, CCTV system operators routinely exercise their prejudices to discriminate against race, age, class or sexual preference. They openly proclaim that this is a necessary part of their duties. One camera operator in Burnley told a Granada documentary “people mainly with shirts and ties are OK. Most people you can tell just by looking at them”. Another said “I tell by the hair”. A recent report by Hull University highlighted endemic discrimination against blacks, gays, minorities and young people.
Electronic tracking is type of surveillance using electronic device like cell phone, electronic tag etc.
Here is comparison of CCTV with electronic tracking:
Unless physically protected, CCTV cameras have been found to be vulnerable against a variety of (mostly illegal) tactics:
1. Some people will deliberately destroy cameras. Some cameras can come with dust-tight, pressurized, explosion proof, and bullet-resistant housings.
2. Spraying substances over the lens can make the image too blurry to view.
3. Lasers can blind or damage them. However, since most lasers are monochromatic, color filters can reduce the effect of laser pointers. However, filters will also impair image quality and overall light sensitivity of cameras. Also, complete protection from infrared, red, green, blue and UV lasers would require use of completely black filters, rendering the camera useless.
CCTV technological development:
It is beyond the scope of this article to discuss in detail various technological developments and innovations of CCTV over years. However, a brief overview of technological developments and innovations is indispensable.
Video analytics (video content analysis):
Video Analytics (VA), also referred to as Video Content Analysis (VCA), is a generic term used to describe computerized processing and analysis of video streams. Computer analysis of video is currently implemented in a variety of fields and industries, however the term “Video Analytics” is typically associated with analysis of video streams captured by surveillance systems. Video Analytics applications can perform a variety of tasks ranging from real-time analysis of video for immediate detection of events of interest, to analysis of pre-recorded video for the purpose of extracting events and data from the recorded video. Relying on Video Analytics to automatically monitor cameras and alert for events of interest is in many cases much more effective than reliance on a human operator, which is a costly resource with limited alertness and attention. Various research studies and real-life incidents indicate that an average human operator of a surveillance system, tasked with observing video screens, cannot remain alert and attentive for more than 20 minutes. Moreover, the operator’s ability to monitor the video and effectively respond to events is significantly compromised as time goes by. Furthermore, there is often a need to go through recorded video and extract specific video segments containing an event of interest. This need is growing as the use of video surveillance becomes more widespread and the quantity of recorded video increases. In some cases, time is of the essence, and such review must be undertaken in an efficient and rapid manner. Surveillance system users are also looking for additional ways to leverage their recorded video, including by extracting statistical data for business intelligence purposes. Analyzing recorded video is a need that can rarely be answered effectively by human operators, due to the lengthy process of manually going through and observing the recorded video and the associated manpower cost for this task. While the necessity for, and benefits of, surveillance systems are undisputed, and the accompanying financial investment in deploying such surveillance system is significant, the actual benefit derived from a surveillance system is limited when relying on human operators alone. In contrast, the benefit accrued from a surveillance system can be significantly increased when deploying Video Analytics. Video Analytics is an ideal solution that meets the needs of surveillance system operators, security officers, and corporate managers, as they seek to make practical and effective use of their surveillance systems.
Video analytics is the use of sophisticated algorithms applied to a video stream to detect predefined situations and parameters. These can include but are not limited to the following.
1. Motion Tracking – Following a moving object across the cameras view
2. Object detection – Detect a moving object in the cameras view
3. Object classification – Identify the type of object moving (Person, animal, Vehicle)
4. Direction Flow – Identify the direction of a moving object
5. Loitering – Alert if object stationary beyond a predefined time
6. Left/Removed object – Alert if an item is left or removed from a predefined area
7. Face detection – Detect and record faces
8. People Counting – count people in and out of a defined area
There are many processes involved in developing a video analytics platform right from obtaining the video data, this can be from either an analogue camera or an IP camera, it could also be with some systems from a video file (avi, wmv). The video images are then passed through image extraction, feature and edge detection algorithms. These will check the image for recognisable details, compares the foreground to the background and differentiates between them by only detecting foreground objects. At this point the systems have enough information to make intelligent decisions based on the pre-set rules and parameters set in the software. It can then either ignore or raise alarm depending on these rules. Along with all the obvious security uses video analytics is being developed constantly and new features create new opportunities in different market places. Areas such as marketing and retail can also benefit from a VA systems as it can track how many people enter a building or area, how long people stay in certain areas. It can also monitor queue lengths, queue times, provide heat maps and show customer flow. All this information allows the end user to have a better understanding of how their business operates and provides measurable performance.
Modern high-definition cameras feature a lot of computer-controlled technologies allowing them to identify, trace, and categorize objects. Video Content Analysis (VCA) is actually the capability of automatically analyzing video to capture and define temporal events which aren’t based on a single image. In other words, it can be regarded as the automated equivalent of the biological visual cortex. Systems that employ VCA are able to recognize changes in the environment, identify and compare objects stored in the database by size, speed, and even color. One can program the camera’s actions based on what it sees – for instance, an alarm can start if a certain object has moved in a specified area, or if it is missing, or if someone has spray painted the lens. Besides, VCA analytics can be used to detect various unusual patterns in a videos environment – the CCTV system can be set to reveal anomalies in a crowd, like a person moving in the opposite direction in airports in the area where passengers are only allowed to walk in one direction, or in a subway where people can’t exit through the entrances. Another feature of VCA is that it can track people on a map by calculating their position from the images. After you linked several cameras, you can track a person through the entire building or area, which is useful for tracking a person without analyzing hours of film. Today the surveillance systems can’t easily identify people from video alone, but if you connect them to a key-card system, you will see the identities displayed as a tag over their heads on the film. A difference in where the VCA technology is located is either the information is processed within the cameras or by a centralized server, because both technologies have their benefits and drawbacks.
Facial recognition system:
It is a computer application for automatically identifying or verifying a person from a digital image or a video frame from a video source. One of the ways to do this is by comparing selected facial features from the image and a facial database. The combination of CCTV and facial recognition has been tried as a form of mass surveillance, but has been ineffective because of the low discriminating power of facial recognition technology and the very high number of false positives generated. This type of system has been proposed to compare faces at airports and seaports with those of suspected terrorists or other undesirable entrants.
Face recognition useless for crowd surveillance:
Using face-recognition technology to scan airport crowds for terrorists is, quite simply, worthless in that situation. As an authentication tool, used in controlled settings, face recognition has real value. Here we can expect a false acceptance rate (FAR) of one in 250. This means that under controlled circumstances….you could expect one false positive out of 250 people when face recognition is used alone. But in uncontrolled settings, such as we’d encounter in a surveillance context, the performance of face recognition falls to absurd depths. With indoor light, and a prior image taken at 1.5m camera-subject separations and another taken at 2m camera-subject separations, the best false detection rate (FDR) was 33 per cent, with a false acceptance rate (FAR) of ten per cent. This means that to detect 90 per cent of terrorists we’d need to raise an alarm for one in every three people passing through the airport. It’s absolutely inconceivable that any security system could be built around this kind of performance.
Next Generation Identification (NGI) – Developed by FBI, USA:
Next Generation Identification (NGI) is a technology developed by FBI, USA. NGI is a face recognition system for CCTV Cameras. By using this technology FBI is planning to catch known criminals. NGI has an algorithm that matches people faces with an archive of mug shots. This new technology has capability to identify people using security camera footage and pictures uploaded to the Internet. It also uses biometric tools like Iris Scans, DNA Analysis and Voice recognition which matches the surveillance with known criminal’s photos and help agencies better identify and catch suspects. This technology can identify faces even from a busy crowded street. As per the reports provided, the project has an accuracy of 92% in identifying the people faces over 1.6 million mug shots.
1. It cannot identify the face of person, if he/she covers his face or wears dark glasses.
2. It only recognizes the known criminals in the database which matches with FBI records but can’t study the aggressive behaviour of people who are ready to attack
3. It can identify only the people but not the deadly weapons like guns, knives, bombs etc
Automatic Number Plate Recognition (ANPR):
Automatic Number Plate Recognition (ANPR) is an important growth product to take off in the world and in fact, it is already beginning to be the biggest potential earner for installation companies. ANPR is the generic term generally used in the UK but other terms are common in other parts of the world such as; NPR (Number Plate Recognition), LPR (License Plate Recognition). If you scan a document into your PC and then open it in a word processor you cannot edit or alter it in any way. This is because it is simply one bitmap made up of thousands of individual pixels. However there is software available, frequently a freebie with scanners that can convert these groups of pixels into characters. This is Optical Character Recognition (OCR), which scans each group of pixels and estimates whether or not it could be a letter and replaces the pixels with the ASCII (American Standard Code for Information Interchange) code for the letter. For instance the ASCII code for the lower case ‘a’ is 01100001. So, the software scans the whole document and produces a page of letters exactly the same as though you had typed them in, which can be edited or manipulated in any way. OCR is the fundamental technology used in ANPR and provides the capability to store and sort data. ANPR cameras need to be a special type and set up within certain important parameters. As a vehicle approaches the camera the software takes a series of ‘snapshots’ and stores them in a file. When the number plate is of sufficient size for the OCR software the frame is scanned and the registration number is converted to ASCII code and held in a list. This continues for a series of images according to the speed and position of the vehicle. The list is scanned for similarities and a ‘favourite’ selected to retain. The system would typically scan and compare 10-15 images, with 5 being considered the minimum for high accuracy but some systems only take one image at a certain position. This then, is the start of the ANPR capture and is totally dependent on the correct set up of camera, lens, illumination, angle of view and configuration. Get one wrong and you have a disappointed customer who won’t pay the bill.
Video Motion Detection devices (VMD):
The primary function of a VMD system is to relieve CCTV operators from the stress of monitoring one or many screens of information that may not change for long periods. The VMD system will be monitoring all the cameras in its system, and only reacting when there is suspicious activity in one of the scenes. During the long periods of inactivity the operator can continue with other tasks, secure in the knowledge that when something occurs the system will immediately respond. Even a moderate sized system, with eight cameras, would prove impossible for an operator to monitor. Eight monitors could not be viewed with any degree of concentration for more than about twenty minutes. If the monitors were set to sequence, then activity on seven cameras is lost for most of the time and would be totally ineffective to detect intruders. With more cameras in a system, the task of detecting intruders becomes impossible and technology must take over the strain. The idea of VMD systems is that the processor is continuously monitoring all the cameras in the system. During this time, the, operator may select or sequence cameras using the conventional switching system. The system may include an additional monitor connected to the VMD system that will normally show a blank screen. When activity in any camera occurs that the VMD system interprets as an intruder, the alarmed camera is immediately switched to the blank monitor and a warning sounded to alert the operator. The operator’s attention, is therefore, immediately focused on the camera covering the alarm. The detection of an intruder can also set off further events, such as setting a video recorder to real time recording, setting a matrix switching system to sequence through a specific series of cameras, etc. The operator can analyse the scene and take the appropriate course of action. An intruder could generate an alarm and be out of view of the camera before it is displayed. The operator would therefore see just a blank screen and be unsure about what to do next. To overcome this, at the time of detection, many VMD systems will capture an alarm image sequence containing one or more freeze frames. This may be displayed as the first view on the previously blank screen. The operator may then examine the scene at the instant of alarm in more detail.
Video Motion Detection is an electronic method of detecting a change in the field of view of a camera. In its simplest form, this is achieved by storing one frame of the video information and then comparing the next frame with this to decide whether there has been a change. The change detected would be a difference in the video voltage, indicating a change of brightness within the scene. This would be initially ignored as an alarm until a further frame confirmed the change, or not. If confirmed as a change of brightness in the scene, then an alarm would be generated. This could cause a contact to close and activate some warning device such as a buzzer, or cause the switcher to select the camera that detected the motion. The sampling process may take somewhere between one fiftieth of a second and one second to detect a change, depending on the method of sampling. This simple detector could be used in an environment where all conditions were absolutely stable and the only possible change in brightness would be due to an intruder. However, the intruder could be a mouse or a person. The system couldn’t differentiate between the two. In addition, by the time the alarm is displayed on a monitor, the cause of it could be out of view. If the scene were being continuously recorded, the event could be reviewed but this may be too late to take effective action.
The figure below shows VMD detecting change in signal:
The upper segment shows genuine alarm and lower segment shows false alarm:
There are really only two types of alarm, genuine alarms and false alarms. Sometimes mention is made of ‘spurious alarms’, unexplained alarms and system failures. These must only be considered as false alarms because the system has alarmed for no apparent reason. A genuine alarm is one created by deliberate nefarious human action, e.g. by movement of a person or vehicle into the detection field or disturbance of the alarm system. A false alarm is one that has no deliberate human input, such as those caused by animals, birds or any malfunction of equipment. One measure of the efficiency of a system is the ‘False Alarm Rate’ (FAR). This is the ratio of false alarms to a time scale, i.e. five per day. The FAR level will depend on many local site considerations. The objective is to reduce this to the minimum without missing any real alarms. Another measure is the ‘probability of detection’ (PD) rate, which is the ratio of detections to the number of attempts in controlled tests. The ideal for PD is 100%.
The 10% Rule:
There is an empirical rule used widely in CCTV system design that in order to distinguish a person on a monitor, they must be at least 10% of the height of the screen. ‘To distinguish’ in this context, means that the image can be seen to be a person. This 10% is also considered to be the minimum resolution necessary for an efficient VMD system to recognise an alarm situation. Many VMD systems will certainly respond to smaller targets, but with the probability of generating a higher number of false alarms, and the difficulty of identifying the cause. There may be occasions where a different factor is required; in these cases the equations can be adapted to the need.
Limitations of Simple VMD Systems:
The limitations of the types described for demanding external situations are as follows.
• Will not cope with moderate changes in light levels.
• Sporadic generation of alarms in high contrast scenes.
• Will not cope with changing weather conditions.
• Lack of size discrimination means compromise in setting up.
• Non-uniform sensitivity with range.
• Will not cope with size variation due to perspective.
• Slow processing speed can miss moving action.
• Inability to discriminate between small high contrast dark and large low contrast objects.
• Prone to false alarm due to camera shake.
• Cell measurements prevent accurate area discrimination.
• Restricted to small areas of view.
• Unlikely to detect a person at 10% of screen height.
• Only simple algorithms can be computed.
• Cannot distinguish between a person moving in a line and a waving object.
• Single processor increases time between frame comparisons.
Closed-circuit digital photography (CCDP):
Closed-circuit digital photography (CCDP) is more suited for capturing and saving recorded high-resolution photographs, whereas closed-circuit television (CCTV) is more suitable for live-monitoring purposes. However, an important feature of some CCTV systems is the ability to take high resolution images of the camera scene, e.g. on a time lapse or motion-detection basis. Images taken with a digital still camera often have higher resolution than those taken with some video cameras. Increasingly, low-cost high-resolution digital still cameras can also be used for CCTV purposes. Images may be monitored remotely when the computer is connected to a network.
Spot aggressive behavior using CCTV:
A computer program can analyze CCTV images and spot aggressive human behaviour nine times out of ten, according to research published in the International Journal of Computational Vision and Robotics. The research is an important step forward in intelligent security systems that could raise an alarm without requiring constant human vigilance. Image-processing experts in Algeria used a geometrical analysis of images to create a silhouette of a person on the screen. The system then maps the movements of the person’s limbs, the team then correlates those movements with aggressive and passive behaviour so that the algorithm learns what particular changes in geometry are associated with aggression. The program can automatically distinguish between hand clapping, waving and a punch being thrown, for instance. The system can also discern whether a person is walking, jogging or running. The resulting algorithm has 90 percent accuracy, compared with other systems the best of which is around 80 percent accurate. On a standard data set the accuracy is as high as 98 percent whereas the best alternative is 95 percent. The team points out that the algorithm is robust and not susceptible to changes in lighting conditions and noise in the images. This allows it to work well in a variety of indoor and outdoor settings, street, airport, sports stadium etc. Moreover, the simplification of the images to human silhouettes reduces the computational overhead significantly and allows the analysis to be carried out quickly without the need for a high-performance computer. With increasing numbers of CCTV cameras monitoring people in city centers as part of crime-reduction efforts, technology that can automate the process of spotting aggressive behaviour without increasing numbers of people to monitor the video streams is becoming more and more important.
Kintense System – Developed in University of Virgina:
Inspired from Microsoft’s gaming sensor Kinect, a research scholar from University of Virgina designed a sensor for CCTV Camera to predict a person’s aggressive behaviour such as kicking, pushing, hitting and throwing. The system Kintense analyses a person’s body and identifies where the joints are in order to create a real-time 3D skeleton figure. This concept is not fully developed, it is still under development.
1. Person need not face camera
2. Recognizes the person’s aggressive behaviour
CCTV software advances:
Some of the most interesting CCTV technology advances are being made in the software that digital CCTV systems use.
1. Automatic CCTV identification and analytics:
The latest trend is the development and adoption of automatic identification and analytics packages. Huge advances have been made, particularly in the fields of sound and gait recognition, along with other advanced suspect identification and tracking systems. It’s cutting out the tedious human effort of monitoring large numbers of screens and making the CCTV operative’s job much more efficient and focused on responding to actual threats.
2. Sound recognition:
Advanced audio recognition CCTV software means that sounds like gunfire, breaking glass or arguments or aggressive voices can be picked up automatically and warnings sent out to the CCTV operative.
3. Gait recognition:
CCTV software can even identify people by how they walk. Facial recognition software is becoming better, but particularly where you have large crowds, it’s hard to identify people by their faces. However, people’s gaits are all individual and hard to fake, and advanced CCTV systems are actually able to identify people by the way they walk.
4. Suspect identification and tracking:
An innovative new ‘tag and track’ system has also been developed by Kingston University. The system identifies the suspect from their appearance and other features, and then ‘tags’ them, so that other cameras on your CCTV network pick up on them and continue monitoring them. Depending on where and when they were first identified, a realistic number of your cameras are notified, rather than system resources being needlessly used up by having the whole system searching for them.
CCTV and cloud computing: Recording off-site ‘to the cloud’:
The latest technology enables recording the captured footage off-site, via the internet over ethernet or cellular networks (3G, 4G and soon 5G). This is saved ‘to the cloud’ – meaning it is stored on computers in data centers – made possible by a visual network adapter (VNA) which also fully encrypts the visual data. VNAs can, as a fail-over precaution, usually store the video straight onto digital media such as SD cards using the site’s internal computer network – wired/ethernet or WiFi (in case the phone-line or mobile signal are lost). A cloud-based management system (dashboard style software) allows playback of the video, either in real-time or recorded, using the internet on a computer and mobile device.
Advantages of video surveillance in the cloud:
Video surveillance is one of the latest applications to reap the potential benefits of a cloud makeover. Let’s briefly examine the potential advantages of putting video surveillance in the cloud. One of the first has to be the ability to make video surveillance both more accessible and affordable, mostly by removing the need for a complex and often expensive local storage and monitoring infrastructure. Local recording is still possible for those that want it – but why not host the required infrastructure in the cloud and deliver access as a service? Then the customer only needs cameras and connectivity. The cloud also makes it a lot easier to include remote and otherwise inaccessible locations in the CCTV mix, especially given the ready availability of WiFi and mobile internet connectivity options. Cameras can be deployed in the most vulnerable areas where fixed line communications simply aren’t available. And then there’s the little matter of managing and monitoring, a task that traditionally involved banks of displays in dedicated control rooms, plus complex VPN technology to protect links to remote sites. Move CCTV into the cloud and all you need is a desktop or laptop PC with a browser and internet access. You can even use a smart-phone or tablet to see what’s going on. Moreover, security can be delivered using the same tried and tested encryption technologies used to routinely protect other internet services. Migrating CCTV into the cloud makes sense for many and addresses numerous shortcomings associated with analogue and digital IP systems – all the more so because it needn’t be an ‘all-or-nothing’ solution. There’s no reason why cloud-based CCTV can’t be deployed alongside – and integrated with – existing on-premise surveillance technologies to enhance and extend the reach of those systems. It makes sense and – as with so many other applications – putting CCTV in the cloud is something we’re all going to get used to.
Aerial CCTV surveillance:
There is growing interest in performing aerial surveillance using video cameras. Compared to traditional framing cameras, video cameras provide the capability to observe ongoing activity within a scene and to automatically control the camera to track the activity. However, the high data rates and relatively small field of view of video cameras present new technical challenges that must be overcome before such cameras can be widely used. Airborne surveillance has been widely used in different range of applications in civilian and military applications, such as search and rescue missions, border security, resource exploration, wildfire and oil spill detection, target tracking, surveillance, etc. Besides using manned aircrafts, the unmanned airborne vehicle (UAV) can also be used for aerial surveillance which is equipped with special sensors (day / night) to image objects in ground and assigns the actual recognition task (surveillance) to the crew or record image data and analyze them off-line on the ground. Pilot less airborne vehicle with sensor carrying platforms transmit data to a ground control station for analysis and data interpretation.
Aerial surveillance technologies include:
1. Aerial Video Surveillance
2. Multi-sensor Fusion
3. Automatic Fuselage Vision Inspection
4. Satellite Image processing
Future Technology in CCTV:
The best CCTV in future would have following features.
1. The future CCTV Camera should be able to detect people away from half a mile
2. The system should be able to recognize the face of the person from any angle i.e. person no need to face camera completely in order to get recognised
3. The system should be able to capture the criminal in a large crowd and send an alert or alarm to security if the record is already in the security database
4. The system should also identify the people carrying deadly weapons and send an alert to security
5. The system should be able to identify the aggressive behaviour of person like kicking, pushing, throwing, jumping and hitting
6. Not only the aggressive behaviour, the system should also identify the unusual behaviour of the people who are possible risk for terrorist attacks. Here the unusual behaviour includes
-Keeping bag/luggage at a particular place and leaving away
-Covering the face completely in order to hide from security surveillance
-Apart from individual person, the system should be able to identify the group of people who are behaving in an unusual manner
7. The system should be able to detect the potential risk of chain snacking, pick pocketing, kidnapping, robbery etc by studying the unusual behaviour of the person or group of people in a crowd and send an alarm to security.
Future CCTV should be such that no criminal can escape police.
Moral of the story:
1. Closed-circuit television (CCTV) means cameras doing video surveillance of activities of a person or place either ‘live’ or through video recording. Closed circuit means installation of directly connected components creating a circuit which cannot be viewed by anybody outside the circuit, unlike a terrestrial television broadcast system which can be viewed by anybody with the appropriate reception equipment.
2. Britain has 1% of world’s population but 20% of its CCTV cameras in 2007. Britain has more CCTV cameras per person than anywhere else in the world. An average British citizen is caught on camera 300 times a day.
3. For image to develop in camera, light must fall on object and reflected light enters camera to fall on image sensor (CCD or CMOS) that convert incident photons into displacement of electrons due to photoelectric effect. The displaced electrons in image sensor would elicit change in voltage and consequent analog signal akin to incident light. This analog signal would be converted into image on a magnetic tape. This is still image. CCTV is nothing but a sequence of still images taken by camera that gives impression of motion and that optical illusion of motion is what we call video. The phi phenomenon is the optical illusion of perceiving continuous motion between separate objects viewed rapidly in succession utilizing visual form of memory known as iconic memory in our brain. Traditional CCTV systems are analogue, tape-based systems. When analog signals from image sensor (CCD or CMOS) are digitized in the camera itself using digital signal processing (DSP), it becomes digital camera which makes digital image of an object. Images are captured as digital files and stored in computer’s hard drive or DVD or NVR or IP camera itself. Traditional analog CCTV system can be upgraded by connecting to DVD which converts analog images into digital images obviating need of video tapes but the captured video cannot be enhanced.
4. Analog CCTV camera (conventional CCTV) has analog signal processing with analog video output while IP camera and digital camera have digital signal processing and digital video output but IP camera additionally has embedded web-server with IP address to transmit video & audio through internet. Digitalization allows distribution of the images over the Internet almost instantaneously to anywhere in the world, and to a variety of devices such as mobile phones or hand held computers.
5. Analog signal is a signal in continuous waveform analogous to the information itself where small fluctuations within the signal are meaningful, and invariably small fluctuations would occur as signals pass from camera through cabling, switching/multiplexing, recording and finally display (many stages), resulting in loss of accuracy and quality of image. Digital signal is a signal where signals are represented by binary numbers, through a series of 0’s and 1’s in relevant order, and this digital signal is transferred through each of these stages with total precision, because each tiny element of the signal is represented by a number. Therefore digital image of an object would closely resemble the object without loss of quality. Also digital images can be copied, transmitted, stored, processed and retrieved without loss of quality.
6. Shorter the focal length of lens and larger the size of CCD (charged couple device), wider the field of view of CCTV camera. One should not confuse field of view with depth of field. The field of view is that part of the world that is visible through the camera and expressed as an angle of view. Depth of field is that part of field of view where objects are in focus of camera. Objects outside depth of field are out of focus of camera even though they may be in the field of view. The distance at which detail can be captured using a camera is its optical range. It varies from few meters to even 10 kilometers.
7. Resolution can be defined as the fineness of detail that can be distinguished in an image. Analog resolution in TVL (television lines) and digital resolution in pixel can be correlated for comparison. Maximum resolution of conventional analog CCTV image is 0.4 megapixels while IP (internet protocol) CCTV image can have resolution from 1.3 megapixels to even 21 megapixels. There is so much resolution within IP CCTV images that the recordings can be expanded to reveal facial identity after an event. Besides better resolution; use of video analytics, large scale wireless transmission, remote access and remote viewing are distinct advantages of IP CCTV over conventional CCTV. There is no need for multiplexing, coaxial cabling, balun adapters, CCTV keyboards, analog VCRs and tapes when IP camera is used. However conventional analog CCTV are cheaper, having easy maintenance and perform well in low light, darkness or fluorescent lighting. 2012’s statistics indicate that only 16% of all CCTV cameras sold worldwide were IP cameras.
8. CCTV camera having infrared LED (light emitting diode) illumination is ideal for covert surveillance at night; the camera can see but the intruder cannot, as IR (infrared) is invisible to the human eye. IR illumination also works well over long distances with optical range up to 300 meters in total darkness. However IR camera should not be misused to invade privacy of others at night.
9. CCTV complements existing police system and not replaces it. Over the time, policemen on the beat become more effective in helping to reduce crime while cameras become less effective. London Metropolitan Police report showed that in 2008 only one crime was solved per 1000 cameras. The significant resources being spent on surveillance are diverting money away from policing methods that could prevent crime and protect the public. Only 3% of street robberies in London were solved using CCTV images, despite the fact that Britain has more security cameras than anywhere else in the world. CCTV is not cost-effective and almost every alternative crime prevention strategy has been shown to be cheaper and more effective.
10. Good street lighting at night is more effective than CCTV for crime prevention. Improved street lighting was associated with a relative reduction in crime of 21 per cent in areas it was introduced, compared to similar areas where there were no such improvements.
11. About 0.05% to 3% crimes are solved by CCTV.
12. CCTV does not reduce feelings of insecurity but increase feelings of discomfort and fear among people.
13. CCTV does not create a physical barrier to crime and therefore can rely to a large extent on changing offenders’ behaviour. Therefore key to the success of CCTV is offenders’ views regarding its effectiveness. Ironically many offenders do not worry about CCTV. Also, potential offenders are aware of public cameras, so they change choice or location of the crime. Offenders can also vandalize or disable CCTV camera and do video sniffing to upload their own video feeds. Offenders can also wear mask to hide their identity.
14. CCTV may improve detection and reporting of violent crime but does not prevent violent crime. CCTV is most effective in preventing car thefts at car parks. Crimes of passion, crimes involving drugs and alcohol, and actions by professional criminals are not prevented by the cameras. CCTV does help the police in gathering evidence but as a deterrent to crime it is something of a failure.
15. Most studies on the effect of CCTV on crime are flawed due to presence of confounding variables (notification of CCTV cameras on site, fencing, improved street lighting, and improved policing), poor methodology and imperfect comparisons. Such studies suggest that CCTV systems have preventative and reactive measures, revive business in desolate or poor areas, increase the efficiency of the police force, build social cohesion, protect the private environment of citizens and assure confidence and ensure feelings of safety and security, thus leading to a more ordered and stable society.
16. Today’s CCTV systems still rely on their human operators. Active surveillance is an intellectually demanding task. It requires you to sit behind a screen and focus intensely. An average human operator of a surveillance system, tasked with observing video screens, cannot remain alert and attentive for more than 20 minutes. Moreover, the operator’s ability to monitor the video and effectively response to events is significantly compromised as time goes by. Therefore the actual benefit derived from CCTV is limited when relying on human operators alone.
17. Employing technological advances like Video Analytics, Automatic Number Plate Recognition and Video Motion Detection can increase prevention, detection and solving of crime significantly and decrease reliance on human operators.
18. CCTV images/video is admissible as primary evidence in court of law provided it is appropriately authenticated. However, 70 to 80 % CCTV footages are useless as evidence in court of law because of inadequacy of the quality of the evidence. This results from poor design & bad installation of the system, cameras are often looking in a different direction and technical problems. Cameras do go blind, and quality & quantity of stored images is poor. A poorly installed, maintained, or functioning CCTV system is only marginally better than having no CCTV system at all.
19. CCTV has indeed become a technological tool of social control forcing individual to discipline themselves according to what is acceptable to society’s elite. Most camera systems have been used to combat anti-social behavior and detect minor offenses including littering, urinating in parks, underage smoking, traffic violations, graffiti, fighting, obstruction, drunkenness, indecency, and evading meters in town parking lots rather than preventing crime.
20. CCTV system operators routinely exercise their prejudices to discriminate against race, age, class or sexual preference. There is widespread discrimination against blacks, gays, minorities and young people. Discrimination is not in response to observed criminal or nuisance behaviours but in response to appearances and categorical suspicions. Ironically many of those excluded from surveillance in response to their looks and trustworthiness are known offenders.
21. The introduction of CCTV creates a profound asymmetry of power between the watcher and the watched; not only are citizens watched by an unknown and unseen eye whose gaze they can neither challenge nor avoid, but data about them is increasingly extracted and automatically processed, in ways they have not given their consent to or even have any knowledge. Widespread CCTV surveillance violates citizens’ rights to privacy and anonymity within the public sphere by jeopardizing both their liberty and dignity. CCTV is often misused to observe someone’s behavior or to obtain personal information. We need a legal framework to strike balance between enhancing security and protecting privacy and personal data.
Dr. Rajiv Desai. MD.
January 6, 2015
The repression of individual liberties (privacy) for the ‘greater good’ of society (security) needs to be debated as CCTV is a classical example of clash of rights. You have right to protect your life while your neighbor has right to privacy; and CCTV installed by you can protect your life and inadvertently invade the privacy of your neighbor. Common sense suggests that security overrides privacy. However, whether CCTV indeed provides security is debatable and whether CCTV is installed for security reason and not to voyeur neighbor is also debatable.
Designed by @fraz699.