Closed-circuit television (CCTV), also known as video surveillance, is the use ofvideo camera to transmit a signal to a specific place, on a limited set of monitors. It differs frombroadcast television in that the signal is not openly transmitted, though it may employ point to point (P2P), point to multipoint (P2MP), or mesh wired or wireless links. Though almost all video cameras fit this definition, the term is most often applied to those used for surveillance
in areas that may need monitoring such as bars, banks, casinos,
schools, hotels, airports, hospitals, restaurants, military
installations, convenience stores and other areas where security is
needed. ThoughVideotelephony is seldom called "CCTV" one exception is the use of video indistance education, where it is an important tool.
Surveillance of the public using CCTV is common in many areas around the world. In recent years, the use of body worn video
cameras has been introduced as a new form of surveillance, often used
in law enforcement, with cameras located on a police officer's chest or
head.Video surveillance has generated significant debate about balancing its use with individuals' right to privacy even when in public.
In industrial plants, CCTV equipment may be used to observe parts of a
process from a central control room, for example when the environment
is not suitable for humans. CCTV systems may operate continuously or
only as required to monitor a particular event. A more advanced form of
CCTV, utilizing digital video recorders
(DVRs), provides recording for possibly many years, with a variety of
quality and performance options and extra features (such as motion detection and email alerts). More recently, decentralized IP cameras, some equipped with megapixel sensors, support recording directly to network-attached storage devices, or internal flash for completely stand-alone operation.
There are about 350 million surveillance cameras worldwide as of
2016. About 65% of these cameras are installed in Asia. The growth of
CCTV has been slowing in recent years.
