Closed-circuit television: Difference between revisions

'''Closed-circuit television''' ('''CCTV'''), also known as '''video surveillance''',<ref>{{cite book|editor1-last=Kumar|editor1-first=Vikas|editor2-last=Svensson|editor2-first=Jakob|title=Promoting Social Change and Democracy Through Information Technology|date=2015|publisher=IGI Global|isbn=9781466685031|page=75|url=https://books.google.com/books?id=jkdLCgAAQBAJ&pg=PA75}}</ref><ref>{{cite book|last1=Dempsey|first1=John S.|title=Introduction to private security|date=2008|publisher=Thomson Wadsworth|location=Belmont, CA|isbn=9780534558734|page=78|url=https://books.google.com/books?id=qQo7oDMSVXgC&pg=PA78}}</ref> is the use of video[[closed-circuit camerastelevision camera]]s to transmit a signal to a specific place, on a limited set of monitors. It differs from [[broadcast television]] in that the signal is not openly transmitted, though it may employ point-to-point, point-to-multipoint (P2MP), or [[Mesh networking|mesh]] wired or [[Wireless|wireless links]]. Even though almost all video cameras fit this definition, the term is most often applied to those used for [[surveillance]] in areas that require additional security or ongoing monitoring ([[Videotelephonyvideotelephony]] is seldom called "CCTV"<ref>Verman, Romesh. [https://books.google.com/books?id=1VUU-eRAObAC Distance Education In Technological Age], Anmol Publications Pvt. Ltd., 2005, pp.166, {{ISBN|81-261-2210-2}}, {{ISBN|978-81-261-2210-3}}.</ref><ref>"Distance education in Asia and the Pacific: Proceedings Of The Regional Seminar On Distance Education, 26 November – 3 December 1986", Asian Development Bank, Bangkok, Thailand, Volume 2, 1987</ref>).

[[File:Bulger cctv.jpg|thumb|The two-year-old [[Murder of James Bulger|James Bulger]] being led away by his killers, recorded on shopping centre CCTV in 1993.; Thisthis [[narrow-bandwidth television]] system had a low [[frame rate]].]]

[[File:Alexis Navy Yard 012 1dsLQLVk7nY.jpg|thumb|left|Closed circuit television cameras captured the perpetrator of the [[Washington Navy Yard shooting]], Aaron Alexis, during his rampage.]]

[[File:SurveillanceCamera2.jpg|thumb|Surveillance camera mounted on the walls of Rosenbad, one of the Swedish's government buildings in central Stockholm, which houses the Prime Minister's office.; Oneone of the parliament's (Riksdagen) building can be seen in the background.]]

About 65% of CCTV cameras in the world are installed in Asia.<ref name="SDM2016">{{cite web|url=http://www.sdmmag.com/articles/92407-rise-of-surveillance-camera-installed-base-slows |website=SDM Magazine |title=Rise of Surveillance Camera Installed Base Slows|date=5 May 2016|access-date=5 January 2017}}</ref> In Asia, different human activities attracted the use of surveillance camera systems and services, including but not limited to business and related industries,{{citation needed|date=February 2016}}<ref>{{Cite book|last=Walton, Greg|title=China's Golden Shield: corporations and the development of surveillance technology in the People's Republic of China|publisher=Rights & Democracy|year=2001}}</ref> transportation,<ref>{{cite web|url=http://www.futuregov.asia/articles/australian-state-government-to-expand-cctv-use-across-transport-network|title=Australian state government to expand CCTV use across transport network|archive-url=https://web.archive.org/web/20150402091654/http://www.futuregov.asia/articles/australian-state-government-to-expand-cctv-use-across-transport-network|archive-date=2 April 2015|url-status=dead|access-date=2015-03-11}}</ref> sports,<ref>{{cite web|url=https://uk.eurosport.yahoo.com/blogs/early-doors/chinese-tv-station-cctv-provide--old-school--analysis-of-afc-asian-cup-match-133815624.html|title=Chinese TV station CCTV provide 'old school' analysis of AFC Asian Cup match|access-date=2015-03-11}}</ref> and care for the environment.<ref>{{cite web| last = Ng | first = Kelly|url=http://www.futuregov.asia/articles/4530-indian-state-government-uses-cctv-to-cut-forest-crimes|title=Indian state government uses CCTV to cut forest crimes|archive-url=https://web.archive.org/web/20141011012135/http://www.futuregov.asia/articles/4530-indian-state-government-uses-cctv-to-cut-forest-crimes|date = 11 October 2014 |archive-date=11 October 2014|url-status=dead|access-date=2015-03-11}}</ref>

There were an estimated 30 million surveillance cameras in the United States in 2011.<ref>{{cite book|title=Technocreep : the surrender of privacy and the capitalization of intimacy.|date=2014|publisher=Greystone Books|location=[S.l.]|isbn=978-1771641227|page=28|url=https://books.google.com/books?id=RExHBAAAQBAJ&pg=PA28|postscript=none}}; {{cite news|title=Surveillance Society: New High-Tech Cameras Are Watching You|url=http://www.popularmechanics.com/military/a2398/4236865/|access-date=31 October 2015|work=Popular Mechanics|date=30 September 2009|postscript=none}}; {{cite news|title=Lawmakers want more surveillance on the ground -- and in the sky|url=http://usnews.nbcnews.com/_news/2013/04/20/17830619-lawmakers-want-more-surveillance-on-the-ground-and-in-the-sky?lite|access-date=31 October 2015|work=NBC News|date=20 April 2013|postscript=none}}; {{cite book|last1=Dempsey|first1=John|last2=Forst|first2=Linda|title=An Introduction to Policing|date=2015|publisher=Cengage Learning|isbn=9781305544680|page=485|url=https://books.google.com/books?id=W4TCBAAAQBAJ&pg=PA485}}</ref> Video surveillance has been common in the United States since the 1990s; for example, one manufacturer reported net earnings of $120 million in 1995.<ref>{{cite web|title=Public Video Surveillance: Is It An Effective Crime Prevention Tool?|url=http://www.library.ca.gov/crb/97/05/|publisher=California Research Bureau|access-date=5 February 2015|date=June 1997|quote=The popularity of CCTV security systems has not gone unnoticed by the manufacturers of camera surveillance systems. ...A leading CCTV manufacturer reported net earnings of $120 million in 1995, compared with net earnings of $16 million the previous year. ...Over 50 percent of all CCTV surveillance equipment sales are to industrial and commercial clients. CCTV surveillance is also very common in the American workplace.|archive-date=17 April 2017|archive-url=https://web.archive.org/web/20170417005043/http://www.library.ca.gov/CRB/97/05/|url-status=dead}}</ref> With lower cost and easier installation, sales of home security cameras increased in the early 21st century. Following the [[September 11 attacks]], the use of video surveillance in public places became more common to deter future terrorist attacks.<ref name="Yesil, Bilge"/> Under the [[Homeland Security Grant Program]], government grants are available for cities to install surveillance camera networks.<ref>{{cite book|last1=Minoli|first1=Daniel|title=Building the internet of things with IPv6 and MIPv6 the evolving world of M2M communications|date=2013|publisher=Wiley|location=New Jersey|isbn=9781118647134|page=86|url=https://books.google.com/books?id=6DW8UbAiaLEC&pg=PT85}}</ref><ref>{{cite magazine|title=The great surveillance boom|url=http://fortune.com/2013/04/26/the-great-surveillance-boom/|magazine=Fortune|access-date=24 January 2016|date=26 April 2013}}</ref><ref>{{cite news|title=Privacy Fears Grow as Cities Increase Surveillance|url=https://www.nytimes.com/2013/10/14/technology/privacy-fears-as-surveillance-grows-in-cities.html|access-date=5 January 2017|work=The New York Times|date=13 October 2013}}</ref> In 2009, there were an estimated 15,000 CCTV systems in [[Chicago]], many linked to an integrated camera network.<ref name=WSJ2009>{{cite news|title=Chicago's Camera Network Is Everywhere|url=https://www.wsj.com/articles/SB10001424052748704538404574539910412824756|access-date=5 January 2017|work=[[The Wall Street Journal]]|date=17 November 2009}}</ref><ref>{{cite web|url=httphttps://abclocal.goabc7chicago.com/wlsarchive/story?section=news7370352/local&id=7370352|title=Chicago Links Police, Private Cameras|publisher=[[WLS-TV]]|year=2010|access-date=2010-08-16|archive-url=https://web.archive.org/web/20100406171238/http://abclocal.go.com/wls/story?section=news%2Flocal&id=7370352|archive-date=6 April 2010|url-status=deadlive}}</ref><ref>{{cite web|title=Chicago's Video SURVEILLANCE CAMERAS: A PERVASIVE AND UNREGULATED THREAT TO OUR PRIVACY|url=http://www.aclu-il.org/wp-content/uploads/2012/06/Surveillance-Camera-Report1.pdf|publisher=ACLU of Illinois|access-date=5 January 2017|date=February 2011|archive-url=https://web.archive.org/web/20160327043725/http://www.aclu-il.org/wp-content/uploads/2012/06/Surveillance-Camera-Report1.pdf|archive-date=27 March 2016|url-status=dead}}</ref> New York City's [[Domain Awareness System]] has 6,000 video surveillance cameras linked together,<ref>{{cite news|title=NYPD expands surveillance net to fight crime as well as terrorism|url=https://www.reuters.com/article/usa-ny-surveillance-idUSL2N0EV0D220130621|access-date=31 October 2015|work=Reuters|date=21 June 2013}}</ref> there are over 4,000 cameras on the subway system (although nearly half of them do not work),<ref>{{cite news|title=Lack of Video Slows Hunt for a Killer in the Subway|url=https://www.nytimes.com/2010/03/30/nyregion/30subway.html|access-date=31 October 2015|work=The New York Times|date=29 March 2010}}</ref> and two-thirds of large apartment and commercial buildings use video surveillance cameras.<ref>{{cite news|title=The State Of Surveillance|url=https://www.bloomberg.com/bw/stories/2005-08-07/the-state-of-surveillance|access-date=31 October 2015|work=Bloomberg Business|date=7 August 2005}}</ref><ref>{{cite news|title=The Building Has 1,000 Eyes|url=https://www.nytimes.com/2013/10/06/realestate/more-surveillance-cameras-at-new-york-residences.html|access-date=5 January 2017|work=The New York Times|date=4 October 2013}}</ref> In [[Washington, D.C.]] there are more than 30,000 surveillance cameras in schools,<ref>{{cite news|title=30,000 Surveillance Cameras Monitor D.C.-Area Public Schools|url=http://www.nbcwashington.com/news/local/30000-Surveillance-Cameras-Monitor-DC-Area-Public-Schools-287297041.html|access-date=31 October 2015|work=NBC Washington|date=1 January 2015|archive-url=https://web.archive.org/web/20151006071902/http://www.nbcwashington.com/news/local/30000-Surveillance-Cameras-Monitor-DC-Area-Public-Schools-287297041.html|archive-date=6 October 2015|url-status=dead}}</ref> and the [[Washington Metro|Metro]] has nearly 6,000 cameras in use across the system.<ref>{{cite news|title=Metro Plans to Triple Number of Security Cameras|url=http://www.nbcwashington.com/news/local/Metro-Plans-to-Triple-Number-of-Security-Cameras-200859881.html|access-date=31 October 2015|work=NBC Washington|date=1 April 2013}}</ref>

Many consumers are turning to wireless security cameras for home surveillance. Wireless cameras do not require a video cable for video/audio transmission, simply a cable for power. Wireless cameras are also easy and inexpensive to install but lack the reliability of hard-wired cameras.<ref>{{Cite web |title=CCTV Camera Installation Guide |url=https://is3tech.com/commercial-security-camera-systems/cloud-based |access-date=2023-10-30 |website=iS3 Tech}}</ref> Previous generations of wireless security cameras relied on analogue technology; modern wireless cameras use digital technology which delivers crisper audio, sharper video, and a secure and interference-free signal.<ref>{{cite book|title=Digital Video Essentials: Shoot, Transfer, Edit, Share By Erica Sadun|url=https://books.google.com/books?id=x_yb92nsqnUC&q=video+digital+vs+analog&pg=PA3|access-date=16 October 2013|isbn=9780470113196|last1=Sadun|first1=Erica|date=26 December 2006| publisher=John Wiley & Sons }}</ref> Now-a-days Smart dual light is used in cameras for night vision and to record brighter videos of dark rooms.<ref>{{Cite web |date=2024-03-27 |title=Smart Dual Light - thaiccd.com |url=https://thaiccd.com/smart-dual-light/ |access-date=2024-06-26 |language=th}}</ref>