The Key Technology Research Of Camera Automatic Focusing Based On Embedded System

Digital imaging system is widely applied in various areas such as military affairs,industry, commerce, family, office, medical equipment and so on. However, auto focustechnology is one of the key technologies for digital imaging system, computer vision, videomonitoring and machine vision. For some important situation like bank, military base, prison,traffic, village, corridor and so on，we need to know what happened in the area, and of coursein modern age, the requirement of safety is increasingly improved, so we monitoring in someimportant occasions. Network deepen ceaselessly, which makes video monitoring technologyhas been rapid development. And then, when we are monitoring, we need to make sure thatthe monitoring image clear enough. And in recent ten years, in all kinds of automatic focusingtechnologies, auto focus technology based on image processing has developed rapidly.This paper firstly introduced the domestic and overseas present situation on autofocusing technology research, and briefly introduced DSP, and then we use DSP as the cameraautomatic focusing embedded system. Secondly, through the understanding of both imagingprinciple and why an image get fuzzy, we deeply researched the key technology of automaticfocusing based on image processing. And via the analysis and comparison for all kinds oftraditional image resolution methods, we improved the image resolution method. So we usedthe improved algorithm of SPSMD, based on Sobel operators, as this thesis’s auto focusingevaluation function. Thirdly, this paper also researched that, we usingDSP(TMS320VC5509A) and its external expansion chips to realize image acquisition andstorage in real time.In the process of determining the best focussing point, we studied many kinds offocussing search methods. At last, via the comparison and analysis, this paper chose theoptimized hill climbing method to complete focus search, and realize automatic focusing.