CCTV or Closed Circuit Television is now common in Commercial establishments, Banks, Traffic control systems, etc to monitor the people’s activities and to prevent the attempt of theft.Its working is simple and similar to a Web camera. The system uses a Video Camera to transfer the video signals to the receiver end which may be a Television or a Computer Monitor. The transmission of signals is short range in the case of wired systems using RF cables and long range in Wireless transmission. Usually the transmission occurs in the range of 2.5-3 GHz. Some have night vision facility also using many Infrared LEDs. In Multichannel systems, many cameras are fixed at different places and a Multiviewer circuit displays the signals from all the cameras on the same monitor. The Digital Video Recorders (DVRs) provide recording facility continuously with extra features like motion detection. The IP based CCTV has mega pixel sensors help to record the data directly to network attached storage devices for completely stand alone operation. High Definition CCTV (HD CCTV) system is now available to identify and track the objects in their field of view.
CCTV Camera is to be protected for its fail proof operation. Some costly types come with dust tight, pressurized, explosion proof casings. Presence of moisture, dust, grease etc can make the camera lens blurry to read. Laser light can easily destroy the camera so colour filters are used in some types.
The CCTV cameras do not require a video capture card and the signal can be directly saved into the computer through the USB port.MPEG format is usually used to make the video in compressed format. Computerized monitoring CCTV image is now developing so that the CCTV operator does not have to look into all screens continuously. These systems do not observe the people directly but track their behaviour body movements, clothing etc.
Wireless CCTV is popular now to avoid wiring in multiple places. Many cameras can be linked wirelessly to a single receiver system to monitor multiple places. These cameras do not require cable connection and only a power cable is necessary. The range of the transmission will be 100 meters or more in many types ideal to monitor multistoried buildings. The modern wireless camera uses digital technology to give crisper audio, sharper video and sends secure and interference free signals to the transmitter.