The paper presents approaches based on traditional phase shifting, flexible least-squares, and signal processing methods in dual phase shifting interferometry primarily applied to holographic moiré for retrieving multiple phases. The study reveals that these methods cannot be applied straightforward to retrieve phase information and discusses the constraints associated with these methods. Since the signal processing method is the most efficient among these approaches, the paper discusses significant issues involved in the successful implementation of the concept. In this approach the knowledge of the pair of phase steps is of paramount interest. Thus the paper discusses the choice of the pair of phase steps that can be applied to the phase shifting devices (PZTs) in the presence of noise. In this context, we present a theoretical study using Cramér-Rao bound with respect to the selection of the pair of phase step values in the presence of noise.
©2006 Optical Society of America
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