How Can CCTV Camera Work ---

CCD Chip Size & Chip SetsThe main function of a CCTV camera is to capture light and convert it into a video signal. At the core of a CCTV camera is a CCD sensor (Charge Coupled Device). This converts light into an electrical signal. Signal processing converts the electrical signal to a video signal that can be displayed on screen or recorded.The CCD is made up of optical detector integrated circuits that use semiconductors. The camera lens focuses light on the CCD image sensor. Photo diodes sense the image areas of light and dark and this results in an electrical charge in proportion to the level of light. A brighter area will result in a higher charge. The photo diodes form a matrix of rows and columns and are called picture cells or Pixels. The charge on the diodes are then processed.

Analogue Versus Digital

Analogue

In an analogue camera system, the camera captures an analogue signal and this is transferred via a coax cable to the DVR (Digital Video Recorder). The DVR converts the analogue signal to a digital one, compresses it and this is stored on a hard drive within the DVR. The footage can be viewed on monitors attached to the DVR or the signal can be sent across a network to be viewed on a computer screen. The DVR can be set up to transmit over the internet and when this is done with an analogue system, all of the cameras’ signals are sent as one stream using one IP address and this makes it very efficient.