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(communications) Any application of television that does not involve broadcasting for public viewing; the programs can be seen only on specified receivers connected to the television camera by circuits, which include microwave relays and coaxial cables. Abbreviated CCTV.
Television transmitted to a particular audience at specific locations via coaxial cables, telephone wires, fiber-optic strands, microwave radio systems, or communications satellites, as compared to open-circuit (broadcast) television intended for the general public. See also Coaxial cable; Communications cable; Communications satellite; Microwave; Optical communications.
Closed-circuit television applications include information display, remote monitoring, instruction, cable television programming, and teleconferences and special events. See also Cable television system.
Many types of closed-circuit television systems produce pictures intended for distant viewing. These images may include those taken from a space probe passing close to a distant planet, or pictures of blast furnaces or other industrial operations that could be hazardous to human observers. The low cost of modern video equipment makes practical the use of small cameras to observe sleeping children at home and to enjoy video images of people far away while chatting with them on the Internet.
Many universities and school systems employ television for teaching. Classrooms may be equipped with closed-circuit television cameras, recorders, and receivers. Lesson material is often presented via video tape recordings, CD-ROMs, or DVD recordings. In other cases, classroom receivers are supplied with signals from specially reserved broadcast channels, cable television channels, or satellite channels. Audio circuits installed at viewing locations sometimes allow two-way conversations between lecturer and students. See also Compact disk; Magnetic recording.
The standardized television broadcast system used at present in the United States, Canada, Mexico, Japan, and some other countries was devised in the 1950s by the National Television Systems Committee (NTSC). Closed-circuit television systems are not required to use NTSC signals, but many do, mainly for economic reasons. If the transmission path to the viewer is of low quality, however, the signal can be modified to meet more closely the characteristics of the transmission system. For example, channel bandwidth can be reduced without loss of image resolution if the user accepts a rate lower than the normal 30 frames per second in the representation of image motion. This is called slow-scan closed-circuit television. Still-frame video images sometimes suffice.
Other applications require high image resolution, great sensitivity to light, the ability to respond to infrared or ultraviolet light, or very rugged system components. Closed-circuit television requirements for high-resolution display can be satisfied by increasing the number of image scanning lines and the overall video channel bandwidth. Industrial standards exist for high-resolution closed-circuit systems.
The digital revolution has affected the design of all kinds of television equipment. Video signals can be converted into digital form and processed by specialized computers, called digital signal processors. In closed-circuit television applications, digital processing can make transmission via the Internet practical and can also provide image enhancement. The advanced television systems now entering service make use of the advantages of digital signal processing to provide high-quality images to the home, to the classroom, and to industrial locations. See also Data compression; Image processing.
Television programming transmitted by cable to specific receivers intended for a select audience. Political groups or candidates will often take advantage of a closed-circuit television system and plan fund-raising events around programs to be shown only to invited guests. Also, live sporting events, such as boxing matches-particularly title bouts-will frequently be televised only on closed-circuit television and shown in specific locations. Tickets are sold to prospective viewers, who will be able to see the event on a television monitor at the location. Some large companies now conduct business meetings on closed-circuit television.
Closed-circuit television (CCTV) involves the use of video cameras to produce images for display on a limited number of screens connected directly to a non-broadcast transmission system (e.g., a network of cables). Commercial cable TV is, technically, an example of CCTV, but the term "closed-circuit TV" is generally reserved for systems serving a small number of screens that are monitored for security purposes. CCTV is a ubiquitous feature of institutional security systems. It is employed by prisons, banks, urban police forces, airports, military organizations, utilities, large corporations, various other organizations, and wealthy individuals. Some specific applications of CCTV are
Two of the most important CCTV applications are discussed in more detail below.
Perimeter security. Prior to CCTV, in order to secure the perimeter of an area, it was necessary to post guards in such a way that their lines of sight covered the entire circumference of the area. With CCTV, it is possible to reduce the number of personnel needed to secure a perimeter by placing TV cameras at strategic points and transmitting the resulting images to a control room where a few guards can monitor many screens. Ideally, these observers will note any suspicious event on their screens and alert a response team. CCTV has thus for decades been a component of the typical Perimeter Intrusion Detection System (PIDS), which combines CCTV with devices designed to detect intrusion by other means (ultrasonic movement detectors, window alarm-contacts, etc.).
CCTV technology, however, has not proved as effective in PIDS applications as was once hoped. As vigilance studies by psychologists confirm, guards who spend hours "screen gazing" at static scenes (> 20 minutes, in tests) tend to become bored and less efficient, and are then likely to miss low-frequency events, such as a figure running up to and climbing over a fence. In the words of Geoff Thiel, a British CCTV-security expert, "Contrary to popular belief, impressive control rooms with large banks of monitors generally do not provide an effective "real time" surveillance service. The vast majority of installed CCTV cameras remain unwatched and incidents are not likely to be detected while they are occurring. CCTV is therefore reduced to a "post-mortem" tool…" (1999 International Carnahan Conference on Security Technology).
Starting in the 1980s, designers sought to combat the bored-guard effect by using automatic Video Motion Detectors (VMDs). These devices are designed to automatically detect scene action by comparing successive image-frames for changes. When change is detected that exceeds a predetermined threshold, an alarm is sounded. A guard then judges whether the alarm is false or valid.
VMDs, however, have not turned out to be a security panacea. There are too many sources of image change, especially in outdoor scenes, for a simple circuit to distinguish meaningful intrusions from nuisance alarms: shifting shadows, wind-shaken foliage, birds, rodents, blowing trash or leaves, camera movement, camera auto-iris adjustments, and the like. Faced with frequent false VMD alarms, guards tend to ignore the system altogether. VMD use is therefore restricted to artificially-lighted indoor spaces or to expensive systems that employ computer processing to reduce the false-alarm rate.
In the 1990s and beyond, artificial intelligence techniques—in particular, expert systems—have been combined with VMD to increase the effectiveness of CCTV. An expert system applies higher-level processing to information extracted from the pixels of the raw CCTV image in order to identify and track objects, usually including human intruders. Such systems are a definite improvement over simplistic VMD, and have proven their potential to ignore waving tree-limbs and rabbits hopping over lawns. However, progress remains slow, as in all artificial-intelligence efforts to navigate uncontrolled, complex, real-world situations. A large number of explicit classification rules, for example, must be generated to enable a program to "understand" a given scene—and a scene may change its appearance radically depending on weather (e.g., fog, snowfall, rain), time of day, number and type of cars in the parking lot, and numerous similar factors. It is, therefore, difficult to make a PIDS expert system expert enough to be authentically useful. PIDS designers continue to emphasize that there is no near prospect of intelligent CCTV systems outperforming human guards, with all their weaknesses.
Public-surveillance CCTV. Surveillance by police of sidewalks, train stations, courtyards, parking lots, and other public spaces has proliferated rapidly throughout Europe and the United States during the last decade, propelled largely by the increased availability of inexpensive electronics. Many major cities, including Copenhagen, London, New York, and Washington, D.C., now possess public-surveillance CCTV systems, most often operated by police departments. In some cases, images from these systems are being processed using facial recognition systems (also termed biometric systems, from the Greek for "life measurement"). Facial recognition systems are software algorithms that seek to extract telltale facial features from video images and match faces in photographs to those in a database. Public-surveillance systems are thus advertised as serving two basic purposes, deterrence of crime in watched areas and identification of wanted persons.
Such systems have been criticized on several grounds. In Britain, where public-surveillance CCTV has been in use since the 1980s, studies have cast doubt on whether CCTV has any tendency to reduce crime through deterrence. Crime sometimes decreases in monitored areas, but many criminologists argue that this is because criminals simply move their activities elsewhere. Further, facial-recognition software has an extremely low success rate. Several systems, including ones deployed by the city of Tampa, Florida and by the U.S. Immigration and Naturalization Service, have been abandoned within months of deployment due to their zero or near-zero success rates. Police databases have also occasionally been used by individuals with access for illegal purposes (e.g., stalking exspouses, blackmailing), and public-surveillance CCTV systems, like any powerful surveillance tool, are vulnerable to such abuse. Further, system operators, who are usually male, sometimes use CCTV systems to voyeuristically observe women; a British study found that 1 in 10 women were targeted for voyeurism by the operators of one public-surveillance system. Studies of operators of public-surveillance systems have also shown instances of selectively monitoring dark-skinned persons. Further, powerful surveillance tools may offer a tempting aid to repression of groups such as political protestors. Many aspects of public-space behaviors that are quite legal are nevertheless confidential or at least personal by nature—courtship behaviors, travel patterns, buying habits, lawyer/client consultations, reading choices, smoking, and more. Many persons dislike the idea of such behaviors being recorded by government officials as a matter of course.
There is also widespread willingness in some countries, however, to give up a large measure of privacy in the quest for security from terrorism. A survey conducted by Business Week in November, 2001 found that 63% of U.S. adults favored increasing use of public-surveillance CCTV and that 86% favored the use of facial-recognition software to scan for terrorists in public places (as was done with taped images of over 100,000 attendees at the 2001 Superbowl). CCTV, enhanced by computer processing, will probably play a growing role in both its traditional security applications and in public life in years to come.
Further Reading
Books
Nieto, Marcus, Kimberly Johnston-Dodds, and Charlene Simmons. Public and Private Applications of Video Surveillance and Biometric Technologies. Sacramento, CA: California Research Bureau, California Public Library, 2002.
Periodicals
Notton, John. "The Use of Technology in Policing the City of London," in proceedings from the International Carnahan Conference on Security Technology, Larry D. Sanson, ed., IEEE, 35–39, 1998.
Sage, Kingsley, and Steward Young. "Computer Vision for Security Applications," in proceedings from the International Carnahan Conference on Security Technology, Larry D. Sanson, ed., IEEE, 210–215, 1998.
Thief, Geoff. "Automatic CCTV Surveillance: Towards the VIRTUAL GUARD," in proceedings from the International Carnahan Conference on Security Technology, Larry D. Sanson, ed., IEEE, 42–48, 1999.
Walters, Peter. "CCTV Operator Performance and System Design," in proceedings from the International Carnahan Conference on Security Technology, Larry D. Sanson, ed., IEEE, 32–37, 1993.
Electronic
American Civil Liberties Union (ACLU). "What's Wrong With Public Video Surveillance?" <http://archive.aclu.org/issues/privacy/CCTV_Feature.html> (December 19,2002).
Closed-circuit television (CCTV) is the use of video cameras to transmit a signal to a specific, limited set of monitors. It differs from broadcast television in that the signal is not openly transmitted, though it may employ point to point wireless links. CCTV is often used for surveillance in areas which need security, such as banks, casinos, and airports or military installations. Increasing use of CCTV in public places has caused debate over public security versus privacy. In industrial plants, CCTV equipment may be used to observe parts of a process that are remote from a control room, or where the environment is not comfortable for humans. CCTV systems may operate continuously or only as required to monitor a particular event.
The first CCTV system was installed at Test Stand VII in Peenemünde Germany in 1942, for observing the launch of V2-rockets.[citation needed] The noted German engineer Walter Bruch, was responsible for the design and installation of the system.[citation needed] CCTV recording systems are often used at launch sites to record the flight of the rockets, in order to find the possible causes of malfunctions.[citation needed] Film cameras are also used for this purpose. Larger rockets are often fitted with CCTV allowing pictures of stage separation to be transmitted back to earth by radio link.[citation needed] CCTV is also used to observe the launch pad before the launch, especially when no person may be there because of safety reasons.[citation needed]
Over 80% of the worlds CCTV cameras are in the UK.[citation needed]
Industrial processes which 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. Use of thermographic cameras allow operators to measure the temperature of the processes.
The usage of CCTV in such processes is sometimes required by law.
CCTV for use outside government special facilities was developed as a means of increasing security in banks. Today it has developed to the point where it is simple and inexpensive enough to be used in home security systems, and for surveillance. Surveillance of public areas in the United Kingdom by CCTV was developed partly in response to IRA bombings. Experiments in the UK during the 1970s and 1980s (including outdoor CCTV in Bournemouth in 1985), led to several larger trial programs in the early 1990s. These were deemed successful in the government report "CCTV: Looking Out For You", issued by the Home Office in 1994, and paved the way for a massive increase in the number of CCTV systems installed. Today, systems cover most town and city centres, and many stations, car-parks and estates. The exact number of CCTV cameras in the UK is not known but a 2002 working paper by Michael McCahill and Clive Norris of UrbanEye[1], based on a small sample in Putney High Street, estimated the number of surveillance cameras in private premises in London is around 500,000 and the total number of cameras in the UK is around 4,200,000. The UK has one camera for every 14 people.
Claims that they reduce or deter crime have not been clearly borne out by independent studies[2], though the government claims that when properly used they do result in deterrence, rather than displacement. One clear effect that has been noted is a reduction of car crime when used in car parks. Cameras have also been installed in taxis to deter violence against drivers[3][4], and also in mobile police surveillance vans.[5] In some cases CCTV cameras have become a target of attacks themselves.[6] Middlesbrough council have recently installed "Talking CCTV" cameras in their busy town-centre.[7] It is a system pioneered in Wiltshire which allows CCTV operators to communicate directly with the offenders they spot.[8] This idea is first known to have appeared in George Orwell's famous cautionary tale Nineteen Eighty-Four.
The use of CCTV in the United States is less common, though increasing, and generally meets stronger opposition. In 1998 3,000 CCTV systems were found in New York City.[9] There are 2,200 CCTV systems in Chicago.[10]
The most measurable effect of CCTV is not on crime prevention, but on detection and prosecution. Several notable murder cases have been solved with the use of CCTV evidence, notably the Jamie Bulger case, and catching David Copeland, the Soho nail bomber. The use of CCTV to track the movements of missing children is now routine.[citation needed]
After the bombings of London on 7 July 2005, CCTV footage was used to identify the bombers. The media was surprised that few tube trains actually had CCTV cameras, and there were some calls for this to be increased.
On July 22, 2005, Jean Charles de Menezes was shot dead by police at Stockwell tube station. CCTV footage has debunked some police claims.[11] Because of the bombing attempts the previous day, some of the tapes had been supposedly removed from CCTV cameras for study, and they were not functional.[12] The use of DVR technology may solve this problem.[13]
A CCTV system may be installed where an operator of a machine cannot directly observe people who may be injured by unexpected machine operation. 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.
A development in the world of CCTV (October 2005) is in the use of megapixel digital still cameras that can take 1600 x 1200 pixel resolution images of the camera scene either on a time lapse or motion detection basis. Images taken with a digital still camera have higher resolution than those taken with a typical video camera.Relatively low-cost digital still cameras can be used for CCTV purposes, using CCDP software that controls the camera from the PC.
Images of the camera scene are transferred automatically to a computer every few seconds. Images may be monitored remotely if the computer is connected to a network.
Closed Circuit Digital Photography (CCDP) is more suited for capturing and saving recorded photographs, whereas Closed Circuit Television (CCTV) is more suitable for live monitoring purposes.
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 London congestion charge is enforced by cameras positioned at the boundaries of and inside the congestion charge zone, which automatically read the registration plates of cars. If the driver does not pay the charge then a fine will be imposed. Similar systems are being developed as a means of locating cars reported stolen.
Opponents of CCTV point out the loss of privacy of the people under surveillance, and the negative impact of surveillance on civil liberties. Furthermore, they argue that CCTV displaces crime, rather than reducing it. Critics often dub CCTV as "Big Brother surveillance", a reference to George Orwell's novel Nineteen Eighty-Four, which featured a two-way telescreen in every home through which The Party would monitor the populace.
The recent growth of CCTV in housing areas also raises serious issues about the extent to which CCTV is being used as a social control measure rather than simply a deterrent to crime.
Quite apart from government-permitted use (or abuse), questions are also raised about illegal access to CCTV recordings. The Data Protection Act 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. The successor to the DPA, the Information Commissioner in 2004 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) has limited the scope of the protection provided by this law, and not all CCTV systems are currently regulated.[14]
A 2007 report by the UK's Information Commissioner's Office, highlighted the need for the public to be made more aware of the "creeping encroachment" into their civil liberties created by the growing use of surveillance apparatus. A year prior to the report Richard Thomas, the Information Commissioner, warned that Britain was "sleepwalking into a surveillance society". [15]
In 2007, the UK watchdog CameraWatch claimed that the majority of CCTV cameras in the UK are operated illegally or are in breach of privacy guidelines. In response, the Information Office denied the claim adding that any reported abuses of the Data Protection Act are swiftly investigated. [16]
In the United States there are no such data protection mechanisms. It has been questioned whether CCTV evidence is allowable under the Fourth Amendment which prohibits "unreasonable searches and seizures". The courts have generally not taken this view.
In Canada the use of video surveillance has grown exponentially.[citation needed] In Ontario, both the Municipal and Provincial versions of the Freedom of Information and Protection of Privacy Act outline very specific guidlines that control how Images and Information can be gathered by this method and/or released.
The first CCTV cameras used in public spaces were crude, conspicuous, low definition black and white systems without the ability to zoom or pan. Modern CCTV cameras use small high definition colour cameras that can not only focus to resolve minute detail, but by linking the control of the cameras to a computer, objects can be tracked semi-automatically. For example, they can track movement across a scene where there should be no movement, or they can lock onto a single object in a busy environment and follow it. Being computerised, this tracking process can also work between cameras.
The implementation of automatic number plate recognition produces a potential source of information on the location of persons or groups.
There is no technological limitation preventing a network of such cameras from tracking the movement of individuals. Reports have also been made of plate recognition misreading numbers leading to the billing of the entirely wrong people.[17]
CCTV critics see the most disturbing extension to this technology as the recognition of faces from high-definition CCTV images. This could determine a persons identity without alerting him that his identity is being checked and logged. The systems can check many thousands of faces in a database in under a second. 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.
Computerized monitoring of CCTV images is under development, so that a human CCTV operator does not have to endlessly look at all the screens, allowing an operator to observe many more CCTV cameras. These systems do not observe people directly. Instead they track their behaviour by looking for particular types of body movement behavior, or particular types of clothing or baggage. The theory behind this is that in public spaces people behave in predictable ways. People who are not part of the 'crowd', for example car thieves, do not behave in the same way. The computer can identify their movements, and alert the operator that they are acting out of the ordinary. Recently in the latter part of 2006, news reports on UK television brought to light new technology developed which uses microphones in conjunction with CCTV. If a person is observed to be shouting in an aggressive manner (i.e., provoking a fight), the camera can automatically zoom in and pinpoint the individual and alert a camera operator. Of course this then lead to the discussion that the technology can also be used to eavesdrop and record private conversations from a reasonable distance (e.g., 100 metres or about 330 feet).
The same type of system can track an identified individual as they move through the area covered by CCTV. This is being developed in the USA as part of the project co-funded by the US Defense Advanced Research Projects Agency. With software tools, the system will be able to develop three-dimensional models of an area and track/monitor the movement of objects within it.
To many, the development of CCTV in public areas, linked to computer databases of people's pictures and identity, presents a serious breach of civil liberties. Critics fear the possibility that one would not be able to meet anonymously in a public place or drive and walk anonymously around a city. Demonstrations or assemblies in public places could be affected as the state would be able to collate lists of those leading them, taking part, or even just talking with protesters in the street.
The long-term storage and archiving of CCTV recordings is an issue of concern in the implementation of a CCTV system. Re-usable media such as tape may be cycled through the recording process at regular intervals. There also may be statutory limits on retention of data under some sort of Data Protection Act. However, individual recordings may be retained for indefinite periods for use in investigations or as evidence in legal proceedings.
Recordings are kept for several purposes. Firstly, the primary purpose for which they were created (e.g., to monitor a facility). Secondly, they need to be preserved for a reasonable amount of time to recover any evidence of other important activity they might document (e.g., a group of people passing a facility the night a crime was committed). Finally, the recordings may be evaluated for historical, research or other long-term information of value they may contain (e.g., samples kept to help understand trends for a business or community).
Unless physically protected, CCTV cameras have been found to be vulnerable against a variety of tactics.
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The difficulty of avoiding CCTV detection often appears in games and films.
Stars of CCTV, the debut album from Staines-based British band HARD-Fi, was nominated for the 2005 Mercury Music Prize.
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