Morphological phase unwrapping

Phase unwrapping is the process of determining the absolute phase given its principal value. In this paper, we show that morphological image processing techniques can be helpful for solving this problem. The proposed procedure consists of three independent modules. The first aims at extracting a region of interest corresponding to the areas where interferences occur. This is achieved by processing the input interferograms with a combination of morphological opening and closing operators. The second finds the high boundaries of the wrapped fringes by enhancing them with a morphological gradient by erosion. Gaps along the fringe boundaries which would lead to errors in the unwrapped phase map are filled in by a morphological region growing segmentation technique. The third module consists in integrating the wrapped phase while taking into account the segmented fringes.