A robust procedure for analyzing fringe patterns obtained from speckle interferometric techniques is proposed. The fringes generally are observed only in a region <i>S</i> of a rectangular lattice <i>L</i>. We give a method for computing (from <i>S</i>) the region <i>R</i>, where the unwrapped phase is to be computed; this computation is done by use of a morphological filter (in particular, a closing filter). We then use a fast-unwrapping algorithm to compute the phase: a preconditioned conjugate-gradient algorithm that uses the discrete Fourier transform.
© 1997 Optical Society of America
Mariano Rivera, Ramon Rodriguez-Vera, and Jose L. Marroquin, "Robust procedure for fringe analysis," Appl. Opt. 36, 8391-8396 (1997)