CCTV stands for closed circuit television. It differs from ordinary television because the signal is not openly transmitted. They are mostly used for surveillance purposes in banks, stadiums, homes and in the streets. Surveillance using CCTV security cameras is common in the UK where there are more cameras per person than any other country in the world. Thus the UK is the country that uses CCTV cameras the most for monitoring public activity. The precise number of cameras in the United Kingdom is not known but it is estimated that those used in private homes number near five hundred thousand units and those used in public places are close to 4.2 million.
Experiments were first done in the UK over two decades, the 1970s and the 1980s. This led to bigger programs and in 1994 these trials were judged to be successful by the government. This spelled the start of massive increases in the number of cameras in the UK. Nowadays there are cameras in city stations, subways, city centers, and car parks. This camera is also in use in the United States but is less common.
The recordings from CCTV security systems are stored mostly on hard drives although tape may be used. There are limits by law of how long data can be kept depending on the country the camera is operating in. Recordings made by cameras are kept for several reasons. Some may include monitoring a store. Recordings also need to be kept for a reasonable amount of time before they are destroyed because they may be need as evidence, in case a crime has occurred in the area. Lastly they may be kept and evaluated for research purposes, such as fashion trends etc.
A growing section in these cameras is the development of IP cameras. These cameras use Internet protocol similar to that used in LAN’s to broadcast video images in digital form. The internet can be used to send these images which would enable people to view images of what is happening on a 3G enabled phone. Another development in these cameras is the introduction of wireless security cameras. These do not need some kind of cable for video or audio broadcasting but merely a cable to supply power to the camera.
Many users will also discover that wireless cameras are very easy and cheap to install. Previously these cameras relied on analog signals to transmit data from the camera. Nowadays the signals are transmitted using digital signals which allow for higher quality audio and video. It also provides an interference free signal which is secure.
There is also more technology available to protect the cameras themselves from being tampered with. CCTV cameras can be prone to illegal attacks. Some people will knowingly destroy a CCTV camera, so in view of this outdoor cameras are being housed in bulletproof material. Some people will also spray material on the lens making the images produced afterwards very blurry. Some cameras come with wipers to wipe the substances off the lens, in view of this. With wireless networks it seems that transmitting a signal with the same frequency as that being emitted by the wireless security camera can jam it.