Auto-Focus And Auto-Exposure Control System Design Based On ARM Processor

This thesis proposed a detailed study and design of a camera auto-exposure andauto-focusing system based on S3C6410microprocessor. Since the system’s dynamic modelcannot be derived easily, intelligent control methods inc luding fuzzy controller and fuzzysliding-mode controller are designed respectively to deal with auto-focus control for CCDcamera in this thesis. The motor rotating angles will be adjusted by the controllers such thatthe positions of the lens can be moved and the objective for obtaining auto-focus can beachieved. The frequency is the significant index for evaluating the sharpness of the image. Inthis study，we first convert the CCD camera output， analog video， to digital video, and thensent the digital video signal to the processor to be filtered. In the same time thehigh-frequency component of the image is extracted to evaluate the clarity of the image. Weuse the high-frequency component of image and the differences of high-frequency componentas the fuzzy controller inputs variables to establish the fuzzy rule base and the membershipfunction. The fuzzy output inferred is converted into motor rotating angles to move the lens sothat the system can achieve auto-focus.In this thesis, the specific design of both the hardware and software are covered. In termsof hardware, including a CCD camera, a video decoder, and the ARM board. On the softwareside, including the transplantation of embedded systems, image acquisition, imagepre-processing.