九步相移抗串扰算法的相移误差分析

The Analysis of Phase Shifting Error in a 9 Step Phase Shifting Algorithm

在横向剪切干涉仪中,使用一种9步相移算法来消除零级衍射光对干涉信号的影响。为了分析相移误差对该9步相移算法相位复原精度的影响,本文通过建立理论模型,推导近似的相位复原误差函数,分析了相位复原误差与相移误差的关系的特性,结果表明这种算法的相位复原误差随着相位角的变化成正弦变化,并且该算法对相移误差不敏感,具有很强的适应性。同时这种9步数相移剪切干涉算法的相位复原误差函数存在两个奇点,相移误差接近奇点时,相位复原误差迅速增大。通过分析奇点位置,对控制相移误差和提高相位复原精度具有指导作用。

A 9 step phase shifting algorithm is used to eliminate the undesired zero order effect in the lateral shearing interferometer.In order to analyze the impact of the 9-step phase shift algorithm phase reconstruction accuracy with phase shifting error,the approximate phase reconstruction error function is derived through the establishment of a theoretical model.The characteristics of phase restored error with phase shifting error are shown in this paper.The results showed that phase reconstruction error of sinusoidal change with the phase angle,the algorithm is not sensitive to the phase shifting error and it is highly adaptive.There are two singular points in the reconstruction error function,phase shift error close to the singularity,the phase reconstruction error increases rapidly.By analyzing the position of the singularity,it is benefit to improve the accuracy of phase reconstruction.