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Digital CCTV
A Digital system converts the continuous analogue video signal into a sequence of separate images or snapshots. Each snapshot contains a complete still video image as at a single moment in time. The snapshot image is defined as a regular matrix of points in the image, the content of each point (or pixel) can be described by a number - hence the digital description. The resolution of the image is defined by the number of pixels, the higher the digital resolution the more numbers required to describe the image.A digital video snapshot is in the same form as computer data, it is therefore possible to use computer technology to store and process this data. We will come onto some of the significant advantages of digital data but one of its disadvantages is that each image contains a comparatively large amount of data, which have implications in processing and storage.
It is important to note that analogue and digital are different. Digital is not just an 'improved' analogue system. There may be instances where a digital system is inappropriate (for example if a camera is linked just to a monitor and no recording or transmission is required), although in most installations the digital recording unit offers significant advantages when configured appropriately.