基于插值法波面拟合的球面光学元件检测

为了实现在线自动化检测球面光学镜片的面形偏差，在已有的光学检测系统基础上，对光学检测系统采集的干涉图样进行图像处理和波面拟合算法研究。首先对干涉图样预处理，再根据球面光学镜片大多是圆形孔径，对预处理后的干涉条纹通过最小二乘法拟合出干涉图样的圆边界，确定数据取值边界点的中心和半径值;然后采用Multi-quadric函数插值法拟合出波面的面形轮廓，计算波面的峰谷偏差EPV值及均方根偏差ERMS值;最后用上述方法对Zygo干涉仪采集的干涉图的处理结果与Zygo干涉仪测试结果进行比较分析。结果表明:通过边界处理可有效提高波面拟合精度，采用multi-quadric函数插值法拟合可以理想的还原出波面，且测量误差与国标相比能够控制在0.2的误差范围内，与Zygo干涉仪检测结果相比可以控制在0.03误差范围内，都能够满足球面光学镜片在线检测的精度要求。

Wavefront fitting with interpolation to detect optical surface deviation

In order to realize on-line automatic detection of surface form deviation of spherical optical elements based on the existing optical detection system, the steps of image processing of interferogram were introduced and the method of fitting the wavefront of interferograms was mainly studied.Firstly the introduction of interferogram pretreatment process was presented. According to the optical elements which were mostly circular, the boundary circle of interferogram was fitted by the least-square method, so as to determine the circle center and raduis accurately. Then the algorithm of wavefront fitting with multi-quadric(MQ) interpolating function was analyzed.After the wavefront of optical elements was reconstructed, the values of EPV and ERMS were calculated. Finally the comparative analysis of the processing results of national standard interferogram was presented.Experimental results indicate that the wavefront fitting accuracy can be improved through boundary processing,the wavefront can be reconstructed ideally by fitting with MQ interpolation method,moreover, the measurement error can be controlled in 0.2 range for national standard interferogram, and in 0.03 rang for Zygo interferometer result, which can satisfy the requirements of the optical element on-line measuring precision.