Wavelet transform method of phase-step determination

摘要

The phase-shifting technique is the most popular phase-retrieving technique applied in optical testing. Most of the phase retrieval algorithms rely on stability and accuracy of phase steps. A sufficiently exact phase-step calibration is necessary for phase measurements with high accuracy. We introduce a new method for phase-step calibration between interferograms. The method is based on a recently introduced continuous wavelet transform demodulation technique. For the method proposed here only two phase-stepped images are required. Simulation results indicate that the phase shift error of the proposed method is less than 0.05%.