Research On Correction Algorithm Of Phase Shift Error In Multi-wavelength Phase Shift Interferometry

Phase shift interferometry is a high-precision measurement technique based on the principle of optical interference.Compared with traditional measurement methods,phase-shift interferometry has the advantages of high precision,non-contact and non-destructive,and has been widely used in industrial manufacturing,optical measurement,biomedicine,and other fields.Single-wavelength phase-shift interferometry is prone to phase ambiguity when measuring objects with large sizes or large optical path differences.In order to solve this problem,multi-wavelength phase-shift interferometry has been proposed and widely used.However,in the actual measurement process,the phase shift error is a common problem,which will lead to the accuracy of phase distribution will be affected,thus affecting the accuracy of measurement.Therefore,it is of great significance to study the multi-wavelength correction algorithm of phase shift error.In this paper,the mathematical description of common phase extraction algorithms is given,and the error sources in the phase shifting system are analyzed.Based on the least square method,an iterative algorithm is proposed to estimate the phase shift error from the residual error,and the calculated results are used to correct the phase shift value.Through iteration of phase calculation and phase shift correction,the phase distribution is reconstructed accurately.Based on the proposed iterative algorithm,a method to estimate the coefficient of the nonlinear higher order term when the phase shift error is defined by polynomial function is given.Numerical simulation and experimental verification show that the proposed algorithm is feasible in correcting phase shift errors.