Stitching interferometry using Computer-Generated Hologram (CGH) based on sub-aperture adjustment aberration of 2-D Chebyshev polynomial

摘要

Limited by the field of view of the computer-generated hologram (CGH), full-aperture measurement of long cylindrical mirror with large curvature have been challenging. This paper reports a stitching interferometry based on sub-aperture adjustment with an aberration model represented by 2D Chebyshev polynomials. Firstly, a mathematical model under null measurement between the sub-aperture adjustment and its corresponding aberration is established by combining 2-D Chebyshev polynomials, which can correct sub-aperture position deviation. Secondly, on the basis of the adjustment aberration model, a global stitching algorithm based on the self-residual iterative algorithm (SRIA) is proposed. The algorithm uses the global stitching matrix and the sub-aperture spatial position constraint of the adjustment aberration model to iterate repeatedly for sub-aperture position. The experimental results verify the validity and feasibility of the proposed method. Finally, compared with full-aperture measurements using CGH, the proposed stitching method can obtain high-precision smooth stitching surface, and the repeatability is better than 0.7 nm RMS (P-V).