用特征多项式构造相移干涉相位提取算式

Algorithm in Phase-Stepping Interferometry Based on Characteristic Polynomial

用相移干涉术测量物体表面形貌时 ,各种误差因素特别是相移器移相误差的影响使得表面形貌的测量偏离了实际值 ,甚至会产生形貌失真的现象。采用傅里叶分析的方法对相位提取算式作了理论分析 ,并根据特征多项式设计分析理论构造了新的、对移相误差不敏感的相位提取算式。经实验验证 ,该算法有效地提高了相移干涉仪测量表面形貌的Ra 值 ,重复测量精度达 5倍以上 。

When applying phase-stepping interferometry to measure a surface, distortion will be caused as a result of various error factors especially the phase-stepping error from the phase shifter. Even seriously flexuosity can be produced. Aiming at the main error sources to the phase-stepping interferometry - the phase-stepping error from the phase shifter, theoretical analyses was made for phase-stepping algorithm by applying Fourier method. Based on the theory of characteristic polynomial, a new phase-stepping algorithm, which is insensitive to disturbance and error, was put forward and improved. Experimental results show that the algorithm has effectively improved the measuring accuracy of the phase-stepping interferometry, and made the measured results more approach the actual numerical value.