环形子孔径拼接算法的精度影响因素分析

优化的拼接算法是环形子孔径扫描测量大口径非球面光学元件的关键问题。针对一种基于离散相位值的环形子孔径拼接算法,从精度评定判据入手,对随机噪声、高阶噪声、重叠区宽度及子孔径数目这几个主要影响因素进行了数值仿真分析。结果表明,该算法对高阶噪声和随机噪声均不灵敏,高阶噪声的影响略大于随机噪声的影响;对口径和相对口径较大的非球面,相邻子孔径间重叠系数应大于 0.15,对于非球面度不大的非球面,重叠系数可大于 0.25, 能以较高精度求得拼接参量。

Analysis for the influencing factors to an annular sub-aperture stitching algorithm

Optimal stitching algorithm is extremely important for testing large-aperture aspherical optical elements by annular sub-aperture scanning technique. In view of an annular sub-aperture stitching algorithm based on discrete phase data, and accuracy evaluation criterion, numerical simulation and analysis for several main influencing factors such as random noise, high-order noise, overlapping width and sub-aperture number are carried out. Analysis results show that the algorithm is insensitive to both high-order noise and random noise. The influence of high-order noise is a bit larger than that of random noise. For aspherics with a large aperture and relative aperture, its overlapping coefficient of adjacent sub-apertures should be more than 0.15. For aspherics with small asphericity, its overlapping coefficient may be more than 0.25 and the stitching parameters with higher accuracy can be obtained.