Fpga-based Image Acquisition, Display Design With The Focusing System

Auto focusing is an important technique to ensure that the image is more distinct in photographic acquisition equipment, both domestic and foreign have made extensive research on auto focusing. From the traditional focus search process by the distance measured or the sensor means, to the focus search methods based on the digital image definition evaluation function, image auto-focus technology is more and more digital and intelligent.This paper discussed the image auto focus system based on the field programmable gate array (FPGA) device, which be applied to the automatic control process of optical fiber. The system first analyzes the definition of CMOS sensor's image, through the gradient operator of digital image processing theory. And then adjust the camera position based on the evaluation results by drive the stepper motor, to find the best imaging point. At the same time, LCD modules was used for interactive control and display during the focusing process.The control logic of image acquisition, stepper motor drive and LCD module display was described by the hardware description language, and then integrate these modules into the system on a programmable chip after the logic simulations were successful. After that, programming the gradient operator, quasi-focus search control and user interface displays by the C language. Finally, the relevant experimental circuits were designed for system experiment, the automatic focusing system was tested by using of RED2-2C70 development board, and determined the focusing evaluation gradient operator and the focus point search methods. System experiments showed that the system can implement the image acquisition, storage and display functions correctly, and the image definition of optical fiber can be analyzed through the evaluation function, the modified climbing search method is designed base on the evaluation curve character of the Laplace function, its maximum search time was less than 6 seconds.