Estimation Techniques in Phase Shifting Interferometry

Measurement of phase of interfered beams in interferometry has been a topic of immense interest for quantifying various physical parameters of interests such as displacement, deformation, or shape of an object under investigation. Several approaches have been employed to measure these parameters and one such approach based on estimation technique has proved to be efficient to measure these quantities of interest. These estimation techniques primarily measure the phase step imparted to the piezoelectric device placed in path of one of the beams in an interferometry setup. Interestingly, these techniques also exhibit the capability of simultaneously measuring dual phase steps of two piezoelectric devices, in the configuration involving four‐beam interferometry. Measurement of phase in two‐beam interferometry or multiple phases in four‐beam interferometry using piezoelectric devices is susceptible to several systematic and random sources of errors. In such cases, estimation techniques have shown to be effect...