光学元件表面疵病检测扫描拼接的误差分析

Error analysis of sub-aperture synthesis for detecting surface defects of optical components

为实现大口径光学元件表面疵病的高效率、高精准的检测,本文提出一种能分辨微米级疵病的光学显微散射扫描成像检测系统,因为该检测系统单个子孔径的物方视场为毫米级,所以检测大口径光学元件需对X、Y方向进行子孔径扫描成像并将子孔径图拼接成同一坐标系下的全孔径图。在进行扫描时,系统的机构误差会被引入到子孔径列阵中,导致子孔径拼接处产生像素错位,甚至造成拼接断裂的情况,从而严重影响疵病等级及位置的正确评定。鉴于此,本文对影响全孔径拼接最敏感的误差因素进行了分析,并根据其特点找到合理减小误差的方法,确保子孔径的正确拼接。

In order to detect the flaws of large aperture optical components more efficiently and accurately,the paper proposes an optic micro-scattering imaging detecting system which can recognize defects with micron size. The order of object view field for single aperture is only several millimeters, therefore, in order to examine defects of large aperture optical compo nents,two-dimension scanning stage is demanded to image the sub-apertures, and all the sub-apertures should be stitched. When scanning,the error of sub-aperture arrays which is induced by the error of institution would result in the mismatching of pixels at the stitching place, and even the failure of stitching, thus, it would affect the evaluation of defects detecting. Therefore,to make sure the successful synthesis of sub-apertures,this paper carried on analysis to the error which can significantly affect the correct stitching of sub-aperture,and figure out how to reduce the stitching error.