Sampling moiré method: A more exact solution

Abstract

An important task in the sampling moiré method is phase measurement of a grating image by using the phase of the moiré fringe from a single-shot image. In the method, by thinning out the image, one gets N phase-shifted moiré fringes, where N is called the thinning-out index. In the conventional treatment, they are considered as phase-shifted patterns with shifts equal to multiples of 2π/N. This is not an exact supposition. It is shown in this work that the exact magnitude of the phase shift is 2π/T, where T is the period of the grating image. According to this fact, the formalism of the technique is modified. The simulation results verify the correctness of the theoretical results.

Keywords

• Sampling moiré method
• Phase shift calculation