Closed-circuit television

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The usage of surveillance cameras is increasing rapidly.

Eric Harris and Dylan Klebold, in the Columbine High School Massacre via CCTV cameras

This article refers to a surveillance system. For the TV service also abbreviated CCTV, see China Central Television.

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 two-year-old Jamie Bulger being led away by his killers, recorded on shopping centre CCTV.

1 History
2 Industrial processes
3 Crime prevention and detection
4 Monitoring for safety
5 Closed Circuit Digital Photography (CCDP)
6 Traffic monitoring
7 Privacy
8 Abuses of technological developments
9 Retention, storage and preservation
10 Special uses
11 CCTV countermeasures
12 See also
13 External links

[edit] History

The first CCTV system was installed at Test Stand VII in Peenemünde in 1942, for observing the launch of V2-rockets. 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. 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. CCTV is also used to observe the launch pad before the launch, especially when no person may be there, because of safety reasons.

[edit] Industrial processes

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 at such processes is sometimes required by law.

[edit] Crime prevention and detection

Sign warning that premises are watched by CCTV cameras

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 centers, 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, "guesstimated" the number of surveillance cameras in private premises in London is around 400,000 and the total number of cameras in the UK is around 4,000,000. 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, 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 [2] [3], and also in mobile police surveillance vans [4]. In some cases CCTV cameras have become a target of attacks themselves. [5] Middlesborough council have recently installed "Talking CCTV" cameras in their busy town-centre. [6]

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. [7] There are 2,200 CCTV systems in Chicago.[8]

The men believed to be responsible for the 7 July attacks on London, captured on CCTV.

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.

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, Jean Charles de Menezes was shot dead by police at Stockwell tube station. CCTV footage has debunked some police claims. [9] Because of the follow-up bombing attempts the previous day, some of the tapes had been supposedly removed from CCTV cameras for study, and they were not functional. [10] The use of DVR technology may solve this problem. [11]

[edit] Monitoring for safety

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.

[edit] Closed Circuit Digital Photography (CCDP)

See also Closed-circuit television camera.

A surveillance image captured using a megapixel CCDP camera.

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.

[edit] Traffic monitoring

Many cities and motorway networks have extensive traffic-monitoring systems, using closed-circuit television to detect congestion and notice accidents.

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.

[edit] Privacy

A surveillance room being surveilled itself.

A mobile closed-circuit TV van monitoring a street market

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. [12]

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. Disturbingly to some, corporations may legally record video even in changing rooms. The Talisman Centre in Calgary, Alberta a fitness centre, has numerous video cameras in the men's changing room that record men changing and showering.

[edit] Abuses of technological developments

Security camera at London (Heathrow) Airport

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.

Security camera outside a McDonalds highway drive-in.

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. [13]

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.

Eye-in-the-sky surveillance dome camera watching from a high steel pole

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 movement, 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., 100m).

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.

[edit] Retention, storage and preservation

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).

[edit] Special uses

A very special use of CCTV is at Hessdalen AMS where by it is used for discovery of unidentified flying objects.
In the earlier days of television, some programs, and selected live sporting events, were shown on closed-circuit television in theaters across the United States. From 1965-1970, the Indianapolis 500 was shown live on closed-circuit television in many movie theatres. The first few WrestleMania events were shown in such a way as well.

[edit] CCTV countermeasures

Criminals have long sought to undermine video surveillance. Unless physically protected, CCTV cameras have been found to be vulnerable against a variety of tactics.

Some will deliberately destroy cameras [14].
Simply spraying certain substances over the lens will make the image too blurry to be read.
Laser pointers will temporarily blind some cameras, [15] and higher powered lasers can damage them. However, since lasers are monochromatic, color filters can reduce the effect of laser pointers.
For wireless networks, broadcasting a signal at the same frequency of the CCTV network is reported to be able to jam it.
Some will shoot at the cameras. Some outdoor cameras, such as those employed by the Chicago Police Department, have bullet-resistant housing.