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Guide to Closed Circuit TV (CCTV)

TRUSTED - Target Recognition Using Surveillance Technology for Evidence and Detection - A campaign to improve the effectiveness of existing video surveillance security systems.

CCTV Camera Operation - in a little more detail

CCTV Camera Controls - Resolution

With modern CCD Closed Circuit Television cameras, the resolution figures quoted for General Purpose units are around 380 - 400 lines Black and White, 330 lines Colour, and High Resolution 560 - 600 lines Black and White, and 400 - 470 lines Colour.

There are also an increasing number of colour cameras on the market which can resolve 520 - 540 lines, and in Doktor Jons humble opinion, they are well worth a look. Having said that, if you consider that in the Broadcast Television industry, there are cameras with CCD imagers that can resolve in excess of 1000lines, it tends to put current CCTV performance firmly in perspective!

< 1/3" Interline Transfer (IT) CCD Imager

This photo shows the working end of a Sony 380 line resolution Black and White CCD imager, seen through a protective window. Note how extremely fine gold wires are used to connect the contact pads located above and below the imaging 'pixel array', with the external solder pins used to mount the "chip" package onto a printed circuit board. The pixel array is the area where thousands of individual light sensitive "pixels"or "picture elements" are located.This is the surface where a lens will bring the sharp image into focus.

The one key consideration for camera resolution which is so often overlooked, is that there is no earthly point in using a High Resolution camera fitted with a very cheap poor quality lens - overall the result would look pretty similar to a General Purpose unit costing much less. Conversely, fitting a very expensive high quality optic on a cheap 'jobbing' camera, is probably also a less than brilliant idea.

You will recall that some manufacturers prefer to quote resolutions as 'pixels' .... not good practice!
A pixel is an individual light sensitive 'picture element', and any given CCD imager may contain hundreds of thousands of them. The problem is that whilst a manufacturer may quote an array figure number, e.g. 795 horizontal x 596 vertical, in practice many pixels are not active imaging elements, so the actual working part of the sensor might reasonably be 752 (h) x 582 (v); this configuration is in fact capable of resolving 520 lines on a colour camera. The bigger the number, the more impressive it appears.

More information on camera controls>

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