2-DIMENSIONAL PHASE UNWRAPPING WITH MINIMUM WEIGHTED DISCONTINUITY

Given an interferometric phase image of a surface profile, the task of two-dimensional phase unwrapping is to reconstruct the profile by add ing multiples of 2 pi to the image. Discontinuities in the unwrapped p hase must be restricted to areas of noise and true discontinuity in th e profile. Such areas can often be identified by their low quality. Th is suggests that the unwrapped phase should be chosen to minimize a we ighted sum of discontinuity magnitudes. An algorithm is presented that computes such an unwrapped phase from any initial guess. The elementa ry operation of the algorithm is to partition the image into two conne cted regions, then raise the unwrapped phase by 2 pi in one of the reg ions, reducing the weighted sum; this is done repeatedly until no suit able partitions exist. The operations are found by creating paths that follow discontinuity curves and extending them to form complete parti tions. The algorithm terminates when no path can be extended. The beha vior of the algorithm and the benefits of weighting are illustrated wi th an example. (C) 1997 Optical Society of America.