DISPLAYING PICTURE FROM MULTIPLE CAMERAS

According to the Technical Experts of iWatch Systems, most CCTV system deploy picture of one camera exactly but for some of systems regulating images from more than one camera are quite difficult. There are several equipments which can be used for displaying picture from multiple cameras:

1)      Switcher: a CCTV switcher is a unit that changes between camera pictures one at a time, the output being viewed on a monitor or passed to the recording device. As switchers can use any VCR to record in true real-time, the fact that they provide true real-time recording unlike a snapshot from a multiplexer means they provide a superior picture quality. This can sometimes out weight the disadvantages that can only record one picture at a time. The disadvantage of the switcher is that it can record the data of one camera at a time.

1)      Quadsplitters: Quad unit enable 4 camera pictures to be displayed on a screen simultaneously. It is usefull to monitor several areas at the same time. With a quadsplitter, one can only record one camera or 4 at a quarter of the screen size.

3)  Multiplexer: A multiplexer allows simultaneous recording of multiple full-sized camera pictures on to one VCR tape providing more comprehensive recorded surveillance that with a switcher or a quadsplitter.

Multiplexer are used when a high degree of surveillance is required and it is necessary to record full-size pictures from a number of cameras at a time. It overcomes the problem of both switchers and screen splitters. The pictures from the camera arrive at the multiplexer and are well unsynchronized.

Functions of Video Multiplexers:

a)      Encoding- Taking a single picture from each camera in turn and feeding it out to a video recorder in rapid succession.

b)      Decoding- Playing back previously encoded recordings showing only the selected camera for display.

c)      Mullti-screen- Showing live pictures in many different formats including PIP and split screen up to 16 ways.

Types of Video Multiplexers:

a)      Simplex- Capable of performing any one of the above functions at any one time.

b)      Duplex- Capable of performing any two of the above functions at any one time. They can simultaneously record and play back.

c)      Triplex- Capable of performing all three functions at the same time. It allows the operator to keep monitoring the site whilst reviewing previously recorded tapes.