Research On Synchronous Phase Shift Interference Test Algorithm

The simultaneous phase shifting interferometry is the best method of anti-vibration interference measurement,which can capture multi phase shifting interferograms simultaneously and instantaneously,therefore influence caused by vibration is eliminated.The Fizeau-type simultaneous phase shifting interferometry can greatly improve the measurement accuracy and application range with co-optical paths.For the purpose of anti-vibration interference measurement of flat surface,a new method of simultaneous phase shifting interferometry base on quarter wave plate is studied in this paper.Using a quarter wave plate as a reference mirror,a pair of orthogonal polarized light are acquired.This system could capture four interferograms with ?/2 phase shift between adjacent ones.The position registration for interferograms is studied in this paper.Two methods of the circle detection based on Hough transform algorithm and phase corretlaion algorithm are realized.The circle interference background map is taken as object in the former algorithm.The contour of interferogram is obtained by domain value segmentation and Canny edge detection operator.Finally,the equation of contour is fitted by Hough transform,and the center coordinates of interferogram can be used as a basis for registration.The interference background map is also taken as object in the latter algorithm.Phase correlation algorithm is used to calculate the relative translation of four interferograms.The reliability and accuracy of two algorithms are verified by experiments.The phase unwrapping algorithm is studied in this paper.The phase unwrapping algorithm based on reliability is used,and the experimental results are compared with the ZYGO interferometer.The difference of PV value is 0.004?,RMS error value is 0.001?.An improved path-independent phase unwrapping algorithm based on total-variation minimum denoising is proposed.The experimental results show that the PV and RMS error values of unwrapped phase with denoised residual phase are better than the unwrapped phase with noised residual phase.