Choice and videocamera adjustment
At job with a videocamera it is necessary to consider, that on the computer the driver of a used videocamera should be established, and the chamber should satisfy to following characteristics. Image sharpness of a number plate strongly depends on an electronic shutter of a videocamera (to be exact from speed of its operation): for motor transport, moving with a speed to 40 km/h, its value should be no more than 1/500 c; it is more 40 km/h - no more than 1/1000 with. If the chosen chamber supposes it, demanded value is established manually. If possibility to establish demanded value manually is not present also a chamber shutter copes in an automode, it is necessary to provide such level of illumination at which the image of a number plate will not be greased in a zone of the control.
The horizontal permission of the black-and-white chambers approaching for definition of registration licence plates of motor transport, is obliged to be not less than 520, colour - not less than 480, the size ПЗС matrixes 1/2 "or 1/3".
Usually, in real conditions of street it is difficult to provide invariable level of light exposure of a controllable zone, therefore special attention it is necessary to give to a choice of an objective for the chamber. To choose it is necessary objectives with automanagement of a diaphragm - cheaper under the price objectives with the fixed diaphragm or its hand control do not allow to receive the high-quality image round the clock.
Is better to use варифокальный an objective (with the motorised or manual adjustment), it will relieve you of necessity to select an objective with the fixed focal length, and will give the chance to be guided at registration number of motor transport most precisely.
For a choice вариообъектива with a necessary range of focal lengths, it is necessary to use following recommendations. The standard width of a controllable zone for the analogue chamber makes 3 - 3,5 m. If to digitize a PAL-signal with the maximum permission (720×576) then the height of signs on a number plate in a shot will make т demanded 12-24 pixels (width of a plate - 72-144 pixels).