相关函数拟合极值法在二维位相板衍射光斑定位中的影响因素

为了提高相关函数拟合极值法在二维位相板衍射光斑亚像素定位中的计算效率，针对相关函数拟合极值法中的模板大小、拟合窗口大小及相关函数三种影响因素进行了详细分析，分析过程以仿真图像检验法为理论基础。分析结果表明，三种影响因素均对计算效率产生较大影响，整像素搜索时模板和拟合窗口大小的选取对定位精度影响最大。同理，对二维位相板衍射光斑亚像素定位实验中的搜索模板和拟合窗口大小进行了优化设计：最佳模板大小为51×51pixel，拟合窗口的最佳大小为3×3pixel，与选用恰好包含整个衍射光斑时的模板（131×131 pixel）相比较，整个定位过程的计算时间缩短了40%，在不损失定位精度的同时有效提高了计算效率。

Improvement of calculation efficiency for locating diffraction spot of phase plate with correlation function fitting extreme method

In order to improve calculating efficiency of sub-pixel location of diffraction spot generated by two-dimension phase plate by correlation function fitting extreme method, three effect factors: template size, fitting window size and correlation function are analyzed in detail. Analyzing results show that the three effect factors all make bigger effect on calculation efficiency and the template and fitting window sizes make the biggest effect on locating precision during integer pixel searching. The optimal design of searching template and fitting window sizes are completed during sub-pixel location experiment of diffraction spot generated by two-dimension phase plate: the optimized template and fitting window sizes are 51×51pixel and 3×3pixel respectively. Comparing with the template of 131×131pixel which just includes the whole diffraction spot, the calculating time of whole locating process is shorted for 40%, so the calculation efficiency is improved without degrading location precision.