A Divided Difference Filter-Based Phase Unwrapping Method

A divided difference filter -based phase unwrapping method was presented for restoring true unwrapped phases from interferograms composed of measured wrapped phases. Firstly, a divided difference filter (DDF) was utilized into the field of phase unwrapping (PU) for wrapped fringe patterns, and was combined with a local phase gradient estimation technique to build a DDF-based PU procedure. Secondly, an efficient and robust pathfollowing strategy was constructed for guiding the path of the DDF-based PU procedure by combining a pixel classification strategy with a heapsort-based path-following strategy embedded with a new phase quality map defined by this paper, which was helpful to reduce time consumption for path search and to increase phase unwrapping accuracy. Finally, the experimental results obtained with simulated and measured interferograms with different fringe patterns showed that the proposed method performed well with acceptable time consumption and achieved more acceptable results from noisy interferograms, compared with some of the most commonly used and representative methods.