ThailandCCTV มีบริการครบวงจรด้านระบบกล้องวงจรปิด CCTV

ThailandCCTV เป็นผู้จำหน่ายและออกแบบติดตั้ง ระบบกล้องวงจรปิด (CCTV) สำหรับ โรงงาน สำนักงาน และที่พักอาศัย จากประสบการณ์ของ ThailandCCTV บริษัทได้คัดสรรผลิตภัณฑ์ที่มี คุณภาพให้กับลูกค้า ผลิตภัณฑ์ของบริษัททุกชิ้นได้รับ มาตรฐานCE และ ISO ดังนั้นท่านจึงมั่นใจใน ผลิตภัณฑ์ที่จะทำให้ท่านคุ้มค่ากับการลงทุน

23 กุมภาพันธ์ 2552

Closed Circuit Television CCTV

Closed Circuit Television (CCTV) is a television transmission system in which live or prerecorded signals are sent over a closed loop to a finite and predetermined group of receivers, either via coaxial cable or as scrambled radio waves that are unscrambled at the point of reception.


CCTV takes numerous forms and performs functions ranging from image enhancement for the partially-sighted to the transmission of pay-per-view sports broadcasts. Although cable television is technically a form of CCTV the term is generally used to designate TV systems with more specialized applications than broadcast or cable television. These specialized systems are not subject to regulation by the Federal Communications Commission (FCC), though CCTV systems using scrambled radio waves are subject to common carrier tarriffs and FCC conditions of service.


CCTV has many industrial and scientific applications, including electron microscopy, medical imaging and robotics, but the term "closed circuit TV" refers most often to security and surveillance camera systems. Other common forms of CCTV include live on-site video displays for special events (e.g. conventions, arena sports, rock concerts); pay-per-view telecasts of sporting events such as championship boxing matches, and "in-house" television channels in hospitals, airports, racetracks, schools, malls, grocery stores, and municipal buildings.


The conception of many of these uses of CCTV technology dates back to the earliest years of television. In the 1930s and 1940s, writers such as New York Times columnist Orrin Dunlap predicted that closed circuit TV systems would enhance industry, education, science, and commerce. Dunlap and other writers envisioned CCTV systems for supervising factory workers and for visually coordinating production in different areas of a factory, and anticipated CCTV systems replacing pneumatic tubes in office communications. In the world of science, closed circuit television was heralded as a way of viewing dangerous experiments as they took place; in the sphere of education, CCTV was seen a way of bringing lessons simultaneously to different groups of students in a school or university.


Many of today's CCTV systems were first implemented in the postwar years. For example, pay-per-view closed circuit sports broadcasts can be traced back to a postwar Hollywood invention known as "theater television," a CCTV system used for viewing sports in movie theaters that became a lucrative source of ancillary revenue for boxing promoters in the fifties, sixties, and seventies. With the growth of cable television and satellite delivery systems CCTV telecasts have become an integral part of the business of sports today, not only in the boxing industry but also in horseracing, baseball, and golf.


Educational TV and video advertising in retail stores are other CCTV applications that originate in the postwar period. The controversial Channel One, a now defunct commercial CCTV channel for schools founded in the 1980s, was only the latest of several CCTV experiments in education dating back to the 1950s. Today's "on-site" media industry, which places video advertising monitors in grocery stores, shopping malls, and other retail sites, dates back to a series of tests involving closed circuit advertising in department stores that took place in the 1940s (See Gannon, 1945).


Although all of these applications of CCTV are fairly common, perhaps the most pervasive use of CCTV is for surveillance. Security cameras are now an ubiquitous feature of many institutions and places, from the corrections facility to the convenience store. In prisons, CCTV systems reduce the costs of staffing and operating observation towers and make it possible to maintain a constant watch on all areas of the facility. CCTV is also used as a means of monitoring performance in the workplace; in 1992, according to an article in Personnel Journal, there were ten million employees in the United States whose work is monitored via electronic security systems. Retail stores often install CCTV cameras as a safeguard against theft and robbery, a practice which municipal authorities have adopted as a way of curtailing crime in public housing and even on city streets. In the United Kingdom, for example, police in several cities have installed closed circuit cameras in busy public areas.


These uses of CCTV technology are not neutral; indeed, they are often a matter of some controversy. These controversies center on the status of legal evidence acquired via closed circuit TV, and on the Orwellian implications of constant perceived surveillance. Police use of CCTV security cameras in Britain has led to charges of civil liberties violations (Dawson,1994.) A 1978 survey on the topic of CCTV in the workplace found that 77% of employers interviewed supported the use of CCTV on the job. However, it also found that a majority of employees felt that CCTV in the workplace constituted an unwarranted intrusion, and favored the passage of laws prohibiting such surveillance. Ironically, the ascendancy of more sophisticated electronic employee surveillance technologies such as keystroke monitoring of information workers has rendered CCTV somewhat obsolete as a visual management technology.


In addition to these civil liberties isssues, another controversy surrounding security cameras concerns their effectiveness in crime prevention. The purpose of CCTV surveillance is usually deterrence of, rather than intervention in, criminal acts. Many security cameras go unmonitored and are thus ineffective as a means of halting crimes in progress. This fact was forcefully demonstrated by a highly publicized juvenile murder case in England in 1992. After the discovery of the victim's body and the apprehension of the perpetrators, police discovered that the initial abduction had been recorded by a shopping center's security cameras.

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  • เวลา 24 พฤษภาคม 2553 13:22 , Blogger fernando กล่าวว่า...

    Hi,

    You have an informative blog. Fixing up surveilance cameras in home and office has become mandatory for security reasons. There are many online stores that sell home security products. To know the best online store you can make an research online.

     

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