R. Vandenhouten et R. Grebe, PHASE RECONSTRUCTION AND UNWRAPPING FROM HOLOGRAPHIC INTERFEROGRAMS OF PARTIALLY ABSORBENT PHASE OBJECTS, Applied optics, 34(8), 1995, pp. 1401-1406
A method for automated phase reconstruction from holographic interfero
grams of nonideal phase objects based on a two-dimensional Fourier tra
nsform is described. In particular, the problem of phase unwrapping is
solved because earlier techniques are inappropriate for the phase unw
rapping from interferograms of partially absorbent objects. A noise-le
vel-dependent criterion for the binary mask that defines the unwrappin
g 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 regio
ns is estimated by a linear least-squares fit to the surrounding unwra
pped pixels.