Auto-focus Algorithm for Moving Target Image
Auto-focus technology is the core part of the automatic optical measure system. Auto-focusing algorithm based on image processing is a longstanding topic in the literatures. The focusevaluation-function is mathematical description used to measure whether the image is focused or not The existing sharpness functions will work well for still image sometimes, but in optical tracking measure system, the size of object in image always changing. Thus, these sharpness functions will lose their function. In this paper, an efficient sharpness function based on normalization method of limited gradients is proposed. This auto-focus algorithM calculates the number of gradients bigger than a threshold between the front frame and nest frame. This threshold is variable according to image features. According to comparison of the simulating results of several focus-evaluation-functions and combination with practical application, Practical applications illuminate the proposed approach is feasible and effective.
image processing sharpness function auto focus evaluation function
Ni Jun
College of Optical and Electronic Technology, China Jiliang University, Hangzhou, Zhejiang 310018, China
国际会议
The Fifth International Conference on Image and Graphics(第五届国际图像图形学学术会议 ICIG 2009)
西安
英文
728-732
2009-09-20（万方平台首次上网日期，不代表论文的发表时间）