摘要
电子经纬仪的自动调焦是仪器实现自动化的重要部分,自动调焦的过程就是镜头按照自动调焦搜索算法来回搜索调焦评价函数求最大值的过程,传统的爬山搜索算法会受到调焦评价函数局部极值的干扰而不能准确聚焦;介绍了一种改进的自动调焦搜索算法,在选择清晰度评价函数基础上,同时考虑图像的调制传递函数(Modulation Transfer Function,MTF),综合判断搜索方向,给出了优化算法的原理和实现;实验结果表明,改进的爬山式搜索算法中Brenner函数值的标准差为0.009 3,MTF值的标准差为0.003 9,平均用时为12s,能有效地排除局部极值干扰,使系统精确、可靠的调焦。
Auto focus is an important part of electronic theodolite＇ s automation. It is the lens＇ back and forth searching process of fo- cusing criterion function for the maximum in accordance with the auto focus searching algorithm. Traditional mountain--climb searching al- gorithm couldn＇t accurately focus when influenced by the partial extremum of focusing criterion function. An improved auto focus search- ing algorithm is introduced. Based on the choice of criterion function and considering the image Modulation Transfer Function （MTF）, the searching direction is determined. The principle and implementation of the optimization algorithm is presented. The experimental results show that the standard deviation of Brenner and MTF can reach 0. 0093 and 0. 0039 respectively in the improved mountain--climb searching algorithm , which can effectively eliminate the disturbance of partial extremum, and the auto focus of the system is accurate and reliable.
出处
《计算机测量与控制》
北大核心
2014年第4期1178-1181,共4页
Computer Measurement &Control
基金
国家自然科学基金项目(41174162)
关键词
自动调焦
电子经纬仪
MTF
评价函数
爬山算法
auto focus
electronic theodolite
MTF
criterion function
mountain--climb searching algorithm
