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Digital CCTV
A digital system converts the continuous analogue video signal into a sequence of individual snapshots, each containing a complete still video image, taken 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) being described by a number - hence the digital description. The resolution of the image is defined by the number of pixels, so 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. There are significant advantages of digital data, but one disadvantage is that each image contains a comparatively large amount of data, which have implications in processing and storage.
It is important to note that digital is not just an improved analogue system, both systems have their role. There may be instances where a digital system is inappropriate (for example if a camera is linked to a monitor with no recording or transmission required), although in most installations the digital recording unit offers significant advantages when configured appropriately.