用于影像测量仪垂直尺寸测量的自动对焦技术  

Auto-focusing Technology in Perpendicular Length Measurement of Video Measuring Machine

作　　者：车一峰 杨国舜 陈立国[1] CHE Yi-feng;YANG Guo-shun;CHEN Li-guo(School of Mechanical and Electrical Engineering,Soochow University,Suzhou,Jiangsu 215137,China;Aerospace Engineering Equipment Suzhou Co.Ltd,Suzhou,Jiangsu 215103,China)

机构地区：[1]苏州大学机电工程学院,江苏苏州215137 [2]航天工程装备(苏州)有限公司,江苏苏州215103

出　　处：《计量学报》2023年第4期521-526,共6页Acta Metrologica Sinica

基　　金：国家重点研发计划(2018YFB2002900)。

摘　　要：影像测量仪垂直尺寸测量的自动对焦精度越高,垂直尺寸测量误差就越小。通过对清晰度评价函数性能指标的比较,选择了改进的Tenengrad梯度评价函数;对焦窗口选择全窗口;提出粗精结合的搜索策略,粗对焦时,使用结合二分法的爬山搜索算法;精对焦时,使用结合全局搜索算法的高斯曲线拟合法。实验结果表明:自动对焦算法鲁棒性良好,对焦精度高,可达到5μm(1/20景深),平均对焦时间为10 s,能满足实时性要求。The higher the auto-focusing accuracy is,the smaller the perpendicular length measurement error of video measuring machine would be.The improved Tenengrad gradient evaluation function is selected by comparing the performance indexes of definition evaluation function.The full window is selected as the focus window.A search strategy combining rough and fine focus is proposed.In rough focus,mountain climbing search algorithm combined with binary search algorithm is used.And Gaussian curve fitting method combined with global search algorithm is used in fine focus.The experimental results show that the auto-focusing algorithm has good robustness and high accuracy which can reach 5μm(1/20 depth of field),and the average focusing time is 10 seconds which can meet the real-time requirements.

关 键 词：计量学 影像测量仪 垂直尺寸测量 自动对焦技术 清晰度评价函数 对焦窗口 搜索策略 

分 类 号：TB92[一般工业技术—计量学]