The paper introduces the design of a kind of video processor with the function of auto-focusing. The video processor receives digital YCbCr video signal. Utilizing a piece of DDR2 SDRAM as frame buffer
the video processor realizes the function of format conversion
frame up-scaling and color space conversion. The paper proposes and realizes an improved gray scale differential auto-focus algorithm and calculates the focus value of the current image real-timely. The mountain climbing searching strategy is applied to control the moving of the focus motor
and the auto-focusing of image is realized. The whole design is realized in VHDL and verified with Xilinx XUPV5-LX110T FPGA developing board.
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