CLOSED-CIRCUIT TELEVISION

Closed Circuit Television (CCTV)

The use of video cameras to transmit 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 monitoring, such as banks, airports, military installations and convenience stores.

Increasing use of CCTV in public places has caused debate over public surveillance 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.

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 in such processes is sometimes required by law.

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. Ope

rators 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.

Closed Circuit Digital Photography (CCDP)

A development in the world of CCTV 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 h

ave 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.

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.

More recent developments

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.

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 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.

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.

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.

CONCLUSION

Video or recording from CCTV 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).

Contributed by : Nik Noor Diana Mohd Noor (2007369692)