A global sub-aperture stitching algorithm and its precision evaluation

Sub-aperture stitching interferometry is a method to test the surface of the large optics, which can effectively extend the lateral range of the standard interferometer and can also enhance its lateral resolution. The stitching algorithm based on the overlapping area plays a very important role in sub-aperture stitching interferometry. Due to the misalignment in the sub-aperture test cycle, relatively tilt and shift are calibrated. And the global stitching method is applied to minimize the differences of phase distributions in the overlapping areas. The inspection of stitching quality of the overlapping area is also necessary after the interferograms which have been stitched. This paper uses the statistical principle to evaluate the quality of the overlapping area.