License plate luminance contrast based camera shutter and gain composite control method

Abstract

The invention discloses a comprehensive method of gain control and a camera shutter based on the brightness and contrast of the vehicle license plate, belonging to the field of intelligent information-collection of the vehicles, image-processing, automatic identification of the vehicles and computer processing system. An initial parameter-setting module, an initial adaptation module and a preciseadaptation module are provided in the instruction module of the industrial control device. When the acquired vehicle images by the camera according to the triggered signals of the induction coil are sent to the industrial control device, the camera is initially adapted in accordance with the initial adaptation module of the industrial control device and the basic images of the vehicles in the positioned license plate are acquired. The device analyzes gray characteristics of the license plate and goes on the precise adaptation to make sure the shutter and gain control and finally sends instruction to the camera to carry out the gain control, thus settles the problem of camera control in identifying the license plates. The invention has advantages of the around-the-clock application of the identification technology in all weather conditions under any circumstances of brightness and the accuracy rate reaches as high as 95%. The invention can be widely applied in traffic and public security areas and others.

Description

technical field [0001] The invention discloses a camera shutter and gain comprehensive control method based on the brightness contrast of a license plate, which belongs to the image processing technology in an intelligent vehicle information collection system and relates to the field of automatic license plate recognition and computer processing systems. Background technique [0002] In the bayonet system of urban roads or expressways, it is necessary to shoot passing vehicles around the clock and automatically recognize vehicle license plates. Since it is not possible to use supplemental lighting equipment such as flashlights that may cause danger to the driver, in order to obtain a vehicle license plate image that can be recognized, the camera must be controlled to a certain extent to achieve the goal. At present, the automatic aperture is basically used to control the incident light of the camera. This method is generally only suitable for large-scale monitoring scenario...

AI Technical Summary

Problems solved by technology

However, the technical solution of this patent document is a license plate character recognition method that combines Laplace transform, region growing method and license plate prior knowledge, which is completely different from the technical route of the present invention.

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