FPGA-Based Auto-Focus Video Surveillance System

Currently, as the safety concept becomes more and more important, the significance of security and protection control is gradually emerging. There are many new things continue to emerge in our daily life, such as the safe city, the intelligent community and the others. At the same time, automation and intelligent of enterprise production and logistics management improved. So video surveillance technology is used in security monitoring, industrial automation and other fields widely. According to the goals mentioned in the Twelfth Five-year-plan Outline for Security Protection Industry, to the end of "12th Five-Year", the average annual growth rate of the security industry will reach about20%, and the annual production will reach5000billion yuan in2015, so it can be predicted infinitely broad prospects for video surveillance as an important part of the security industy.Video surveillance is generally monitoring process of events, the specific details of the event are not clear enough. This is not conducive to the future forensic. The auto-focus video surveillance system merges auto-focus technology with the video monitor, auto-focus on parts we are interested in, so that the target is clearly visible, it can improve the monitoring system.The auto-focus video surveillance system is implemented on the fpga chip, it mainly includes two parts:the realization of the hardware system and software design. The system is realized on the basis of DE-2, we produces PCB of the drive module and the original image acquisition module. Taking Quartus II and Nios II as the main development software. Through customizing and realizing the whole system CPU and related peripherals, and writing system’s programs on the Nios II, the whole system is completed.A reasonable choice of the focus area can reduce the amount of data processing, also by the choice of region of interest can eliminate the impact of non-interest region of the picture to the evaluation function curve. This paper presents a new regional selection, it weighted to enhance the attention on the region of interest, Compare the various the evaluation function value of regions to select a limited part of the image to compute, it greatly reduces the amount of data processing, but also a certain degree of self-adaptive. This paper assess several common focus evaluation functions, and then Selectes the Brenner function as the image clarity evaluation function because of the good apprehensive properties. Finally, improves traditional climbing search algorithm.We design the system as follows:we designs IIC controller to Configure the CMOS image sensor to output parallel data, and then designs a IP core to capture the original image data, finally, analysis auto-focus algorithm and output the motor drive signals to control the stepper motor’s rotation direction and rotation angle. And through these steps, the auto-focus function of the video surveillance system can be achieved.