Two-step iterative algorithm immune to tilt shifts for phase extraction

A two-step iterative algorithm (TSIA) immune to tilt shifts is proposed for phase extraction in phase-shifting interferometry (PSI). The TSIA constructs a model of the least-squares iteration of the phase distribution and the tilt shifts based on parametric decoupling. Finally, the phase distribution is extracted via the least-squares method. The experimental results show that the PTI has high accuracy and fast iterative convergence speed for the conditions of the large amplitude of tilt shifts, closed fringes, nonuniform background and modulation.