Closed-circuit television (CCTV) is the use of television cameras for surveillance.
The use of CCTV surveillance cameras has been in steady growth for the last 25 years of the 20th century and CCTV cameras are becoming ubiquitous in many western cities in the 21st century.
Proponents of CCTV suveillance say that is has the effect of reducing crime in the areas under surveillance. Opponents of CCTV point out the loss of privacy of the people under surveillance, and the negative impact of surveillance on civil liberty. Furthermore, they argue that CCTV displaces crime, rather than reducing it.
George Orwell predicted the intrusive use of CCTV in the form of the two-way "telescreens" in every home in his novel Nineteen Eighty-Four.
The combination of CCTV with facial recognition technology 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.
See also: Bugging
Closed circuit TV (CCTV) - where the picture is viewed or recorded, but not broadcast - initially developed as a means of security for banks. Today it has developed to the point where it is simple and inexpensive enough to be used in home security systems, and for everyday surveillance.
The widespread use of CCTV by the police and governments has developed over the last 10 years. In the UK, cities and towns across the country have installed large numbers of cameras linked to police authorities. The justification for the growth of CCTV in towns is that it deters crime - although there is still no clear evidence that CCTV reduces crime. 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.
The first CCTV cameras used in public spaces were crude, low definition black and white systems. Modern CCTV cameras use 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.
Currently, in some areas of the UK such as London, CCTV is being combined with computer imaging systems to track car number-plates. This is being developed in part as a security measure, or as a means of identifying cars reported stolen. But there is no reason why a network of such cameras could be used to track the movement of individuals. The proposed road tolling system for London will also rely on reading car number plates to generate billing information - therefore producing a potential source of locational information on persons or groups.
Critics see the most disturbing extension to this technology is the recognition of faces from high-definition CCTV images. With this technology, it would be possible to determine a person's identity without the need to stop and ask them in the street, or even alert them that their identity is being checked and logged. The systems can check many thousands of faces in a database in under a second.
The latest developments in CCTV and imaging techniques, being developed in the UK and USA, is developing computerised monitoring so that the CCTV operator does not have to endlessly look at all the screens. This also means that an operator can run 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. In public spaces people behave in set and 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. Potentially, waiting in a busy street to meet someone could trigger this system.
The same type of system can, if required, go one step further and track an identified individual as they move through the area covered by CCTV. This is currently 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.
The development of CCTV in public areas, linked to computer databases of people's pictures and identity, presents a serious breach of civil liberties to many. 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.