In-situ sub-aperture stitching measurement based on monoscopic phase measuring deflectometry

This study introduces a novel sub-aperture stitching method based on monoscopic deflectometry for measuring large-aperture optical surfaces. The proposed method involves capturing sub-apertures of the surface under test (SUT) at different fields of view by rotating the SUT, and utilizing the gradient deviation and form deviation at the overlapped areas of adjacent sub-apertures as an objective optimization. This approach not only corrects the system calibration error but also improves the relative positions between sub-apertures. Then the SUT is reconstructed by integrating the global gradient to achieve full-aperture measurement of the SUT. The feasibility of the method is validated through experiments, demonstrating that the stitching accuracy is comparable to that of off-site optical measuring instruments.