A stochastic method for generalized data reduction in holographic moiré

A novel generalized phase shifting method is described in this paper. The method enables the simultaneous determination of phase information carried in both moiré and carrier in holographic moiré. In holographic moiré, two simultaneous phase shifts are required for the recording of a frame. A direct stochastic algorithm for global search is applied for the exact determination of these simultaneously applied phase steps. The phase steps are varied by changing the path lengths in the interferometer by means of PZT devices, which in general show a nonlinear response. The algorithm can be utilized to characterize the nonlinear response of the PZTs and the determined phase steps are subsequently applied in a linear regression technique for the simultaneous extraction of phase information in holographic moiré. The evaluation of the algorithm has been carried out using computer generated moiré fringes.