Fast quality-guided phase unwrapping algorithm through a pruning strategy: applications in dynamic interferometry

The quality-guided phase unwrapping algorithm is one of the most employed spatial algorithms due to its computational efficiency and robustness. It uses a quality map to guide the unwrapping process such that pixels are processed according to their quality values from highest to lowest. Several improvements have been proposed during the last few years with the purpose of using it in time-demanding applications. However, many of the proposals depend on the distribution of the values on the given quality map. In this paper, a novel pruning strategy based on a red-black tree data structure is proposed, whose complexity time is independent of the distribution of the given quality map. We take advantage of the partial ordering of the branches in a red-black tree together with a pruning strategy to speed up the unwrapping process. Experimental results, using real and simulated data, show that the complexity time of our proposal improves the existing quality-guide-based algorithms. Also, a series of interferometric patterns of a time-varying phase distribution experiment have been processed showing that our proposal can be used for real-time applications. The source code of the implemented algorithms is publicly available.