Parameter mismatch phase extraction method for spatial phase-shifting interferograms

Mismatch of interferogram parameters, such as the contrast and the fringe frequency inconsistency, can lead to phase error in simultaneous phase-shifting interferometry. In the dynamic Fizeau interferometer (DFI) based on the lateral displacements of light sources, an extended light source is used to suppress coherent noise. Aiming at the contrast mismatch generated by the extended light source and the inherent fringe frequency mismatch of the DFI, We propose a phase-extraction method to solve these problems. Based on this dynamic interferogram model, a linear relationship is constructed between the tilt angle and interferogram contrast, carrier frequency error, phase-shift error. Use the two steps of initial estimation and fine iterations to extract the phase. The RMS of the residuals was better than 1.5 x 10(-5)lambda for the simulation and 0.004 lambda for the experimental calculation, which demonstrates that the ripple error was suppressed during phase extraction.