Piecewise polynomial phase approximation approach for the analysis of reconstructed interference fields in digital holographic interferometry

This paper proposes a new approach for the analysis of reconstructed interference fields in digital holographic interferometry. In the proposed approach the interference phase to be estimated is conceived as a piecewise polynomial signal; consequently, each segment of the reconstructed interference field is modeled as a polynomial phase signal (PPS) with constant or slowly varying amplitude. Unwrapped phase distribution is then directly computed using the maximum likelihood estimation. Salient features of the proposed approach are: it provides accurate phase estimation from a single record of the interference field; it avoids cumbersome and error prone filtering and 2-D unwrapping procedures; it paves the way to adapt well established PPS analysis tools available in signal processing literature for the phase estimation in holographic interferometry.