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Technology of CCTV

Closed-circuit television (CCTV) has become a popular tool for preventing and detecting criminal behavior, or simply monitoring what is going on inside or outside premises. In its simplest form, the technology of CCTV consists of a video camera, a monitor and a recorder linked together so that the owner can view live or recorded pictures.
  1. Cameras

    • A simple CCTV system might consist of just a single camera, but multiple camera systems allow several images to be viewed one after another, or at the same time, on one or more monitors. CCTV cameras can be fixed in position, or panned and tilted by remote control to focus on activity in a particular area. Zoom lenses can provide a broad or close-up view of the monitored area. Technological advances have allowed CCTV cameras to become smaller, use infrared night vision and transmit pictures over the Internet.

    Recording

    • CCTV systems can record in black and white or color and to analog video tape or digital media, such as hard-disk drive. Digital recordings are easier to store and faster to review than analog recordings. Videotapes are easy to remove from the system and hand over to law enforcement agencies, whereas supplying digital recordings in a usable format, may be more difficult.

    Facial Recognition

    • Some CCTV systems can automatically recognize human faces, either by measuring the distance between specific points on a face, or comparing the face with a library of standard facial patterns. When the system matches a face it alerts the operator, who can decide what action, if any, to take. The accuracy of facial recognition CCTV systems varies widely from application to application. Some CCTV systems -- including those triggered by sudden changes in noise levels, such as shouting -- can also record audio. Generally speaking, audio cannot be recorded legally without proper justification.

    Limitations

    • CCTV systems do have some technical and operational limitations. Cheaply made, improperly installed or improperly maintained CCTV cameras can be vandalized, may not perform well under poor lighting conditions, or may simply break down altogether. CCTV systems work best in open areas, where a high degree of coverage is easy to obtain. Whatever the layout of the monitored area, camera equipment and positioning must produce images of sufficient quality to make the system worthwhile. If a CCTV system is supposed to provide identification of criminal suspects, for example, then grainy, partial images are of little use.


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