A method for automated phase reconstruction from holographic interferograms of
nonideal phase objects based on a two-dimensional Fourier transform is described. In
particular, the problem of phase unwrapping is solved because earlier techniques are
inappropriate for the phase unwrapping from interferograms of partially absorbent
objects. A noise-level-dependent criterion for the binary mask that defines the
unwrapping path for the flood algorithm is derived. The method shows high noise
immunity, and the result is reliable provided that the true phase is free of
discontinuities. The phase distribution in the outmasked regions is estimated by a
linear least-squares fit to the surrounding unwrapped pixels.
© 1995 Optical Society of America
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