In phase-shifting interferometry using narrow-bandwidth light sources, ripple noise introduced by multiple error sources is one of the key factors limiting its wavefront calculation accuracy, this study proposed a generalized ripple suppression algorithm (GRSA) in its standard measurement scenarios. The distribution law of ripple errors caused by different error sources were investigated, and a mathematical model was established to decompose the wavefront shape components. The ripple components in wavefronts can be calculated and directly subtracted via two least-squares fittings on multiple wavefronts containing different ripple errors. Feasibility of the GRSA was verified through simulations and experiments, and the root mean square error of the simulated wavefront reaches 2.1 x 10-5 lambda. Factors affecting the accuracy of phase calculation and several special cases were analyzed, and optimization schemes for algorithm parameters were provided based on the analysis results. The experimental and simulation results show that the GRSA can effectively improve measurement accuracy and repeatability by suppressing the ripple error in the wavefront.
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