数字式光学传递函数测量的自动对焦技术  

The Auto-focus technique for digital MTF measurement system

作　　者：于冬[1] 李晓英[1] 吕乃光[1] 邓文怡[1] 

机构地区：[1]北京机械工业学院电子信息工程系,北京100085

出　　处：《北京机械工业学院学报》2004年第4期27-30,共4页Journal of Beijing Institute of Machinery

基　　金：机电系统测控北京市重点实验室开放研究项目[项目编号:KF20021123202]

摘　　要：为了提高数字式光学传递函数测量的精确度,介绍了2种自动对焦评价方法:锐度函数法和均方差函数法。系统采用步进电机驱动微动工作台,实现CCD沿光轴方向的直线运动,其中CCD用于接收图像,通过搜索对焦评价函数最大值来完成自动对焦。实验结果表明在该系统中锐度函数法作判据的效果要优于均方差函数法,最后分析误差因素并提出修正途径。To improve the accuracy of digital MTF (modulation transfer function) measurement system, two auto-focus evaluation methods (acutance function method and mean square error function method) are introduced. A stepping motor is used to drive the workbench and make CCD move along the rays in a straight line.CCD is employed to receive the image of target. Auto-focus is accomplished by searching the maximum value of evaluation functions. Experiment shows that acutance function method is better than mean square error function method. The error factors are analyzed and corresponding improvement approaches are put forward.

关 键 词：光学传递函数 CCD 自动对焦 均方差 接收 锐度 步进电机驱动 函数法 途径 最大值 

分 类 号：TH74[机械工程—光学工程] G633[机械工程—仪器科学与技术]