子孔径拼接检验法中倾斜的影响及消除方法

Influence of tilt in stitching interferometry and how to eliminate it

在子孔径拼接检测大口径光学平面时,子孔径检测的数据往往存在倾斜,它将会导致拼接的数据沿着一个方向的倾斜累加,最后引入很大的倾斜误差。由于这种倾斜误差难以手动修正,通过实验,先用最小二乘法编制软件对所测子孔径数据进行消除倾斜处理,然后把去倾斜的子孔径数据进行拼接处理,对比消除倾斜的子孔径拼接结果与全口径直接检测结果,证明了去倾斜处理在子孔径拼接检测处理中的有效性。

During the test of large plane optics by stitching interferometry, acquired the data of sub-aperture test often include influence of tilt, and one sub-aperture＇s tilt may leads to all stitching data tilt in the direction, which will bring large error at last. Moreover, the tilt can＇t be eliminated manually. So we remove tilt from sub-aperture＇s measurement by software which uses the algorithm of the least-square method before stitching. The data are measured in stitching interferometry and in direct measurement respectively. The result proves that eliminating tilt before stitching is valid.