Study On All-weather Vehicle Image Acquisition

In the field of All-Weather Monitoring System, it is always a technical puzzle to capture the image of high-speed vehicles under environmental light alterations. The basis of the License Plate Recognition is the legible vehicle picture, where considerable attention has been arisen and much study has been developed. Some CCD vendors produce Two-Channel Video device: Color Mode on the day and Gray Mode at night, just to increase the dynamic range. For the purpose of reducing the requirement level of the vehicle photo's quality, some venders try to implement high-level Light Compensation, while some use Flash-Light Compensation. All these efforts gained some achievements, but the final solution is still on going.This dissertation expatiates one design of the Flash Light Compensation in image equipments based on Video Synchronization technique, which includes the following two aspects: 1, the Video Synchronization Compensation technique; 2, the embedded system integration, including the compensation system, the image collection, image transmission and image recognition.This dissertation also researches the Video Synchronization Compensation technique, calculates the compensation light flux and light flash moment, and develops a system based on our analysis. We defined a criterion, which fixes coming-vehicle-trigger-signal, field synchronization signals and the flash-light-trigger-signal at the same position. The experimental results also prove that this system has reached the application goal.Last but no least, the dissertation includes the design of the embedded system, which integrates SAA7111 chip (video processing unit), CPLD (sample control unit) and Cy7c68013 (USB2.0 transmission unit). Furthermore, we converted the idea designinto applicable PCB board, successfully finished elementary debugging, and the debugging of the whole system is ongoing.