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Closed-Circuit Television

​Closed-circuit television(CCTV), also known asvideo surveillance,[1][2]is the use ofclosed-circuit television camerasto transmit a signal to a specific place on a limited set of monitors. It differs frombroadcast televisionin that the signal is not openly transmitted, though it may employpoint-to-point,point-to-multipoint(P2MP), ormeshwired orwireless links. Even though almost all video cameras fit this definition, the term is most often applied to those used forsurveillancein areas that require additional security or ongoing monitoring (videotelephonyis seldom called "CCTV"[3][4]).

The deployment of this technology has facilitated significant growth in state surveillance, a substantial rise in the methods of advanced social monitoring and control, and a host of crime prevention measures throughout the world.[5]Though surveillance of the public using CCTV is common in many areas around the world, video surveillance has generated significant debate about balancing its use with individuals'right to privacyeven when in public.[6][7][8]

Inindustrial plants, CCTV equipment may be used to observe parts of a process from a centralcontrol room, especially if the environments observed are dangerous or inaccessible to humans. CCTV systems may operate continuously or only as required to monitor a particular event. A more advanced form of CCTV, usingdigital video recorders(DVRs), provides recording for possibly many years, with a variety of quality and performance options and extra features (such asmotion detectionandemailalerts). More recently, decentralizedIP cameras, perhaps equipped with megapixel sensors, support recording directly tonetwork-attached storagedevices or internal flash for stand-alone operation.