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基于衍射理论的分块镜共相位误差检测中,衍射光斑最高峰峰值位置的定位精度直接影响最终的测量精度,峰值定位精度受限于CCD的像元尺寸。针对衍射光斑的特点及最高峰峰值位置亚像元的定位精度要求,提出了基于高斯拟合的最高峰峰值位置的定位方法。在采样间距为5μm,采样点在10个左右的情况下,定位精度高于600nm,与传统的质心法及Hilbert变换法相比,精度可以提高20%以上,且鲁棒性好。实验结果表明,该方法是一种有效的亚像元精度的峰值定位方法,为提高共相位误差的测量精度提供有效途径。
In the co-phase error detection based on the diffraction theory, the location accuracy of the highest peak and peak location of the diffracted light spot directly affects the final measurement accuracy. The peak location accuracy is limited by the pixel size of the CCD. According to the characteristics of the diffraction spot and the positioning accuracy of the sub-pixel at the peak-to-peak position, a method of positioning the peak-to-peak position based on Gaussian fitting is proposed. With the sampling interval of 5μm and the sampling point of about 10, the positioning accuracy is higher than 600nm. Compared with the traditional centroid method and Hilbert transform method, the accuracy can be improved by more than 20% and the robustness is good. The experimental results show that this method is an effective sub-pixel precision peak location method, and provides an effective way to improve the measurement accuracy of the co-phase error.