In [[Factory|industrial plants]], CCTV equipment may be used to observe parts of a process from a central [[control 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, using [[digital video recorder]]s (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 camera]]s, perhaps equipped with megapixel sensors, support recording directly to [[network-attached storage]] devices, or internal flash for completely stand-alone operation.
By one estimate, there will be approximately 1 billion surveillance cameras in use worldwide by 2021.<ref>{{Cite web|last=Nash|first=Jim|date=2020-01-10|title=Global sales of video surveillance equipment projected to surpass $20 billion this year|url=https://www.biometricupdate.com/202001/global-sales-of-video-surveillance-equipment-projected-to-surpass-20-billion-this-year|access-date=2020-10-26|website=Biometric Update|language=en-US}}</ref>{{update inline|date=September 2021}} About 65% of these cameras are installed in Asia. The growth of CCTV has been slowing in recent years.<ref name="SDM2016">{{cite web|url=http://www.sdmmag.com/articles/92407-rise-of-surveillance-camera-installed-base-slows|title=Rise of Surveillance Camera Installed Base Slows|date=5 May 2016|access-date=5 January 2017}}</ref>{{Unreliable source?|date=September 2022}} 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.<ref>{{Cite book|title=Encyclopedia of the City|last=Caves|first=R. W.|publisher=Routledge|year=2004|pages=114}}</ref>
