Phase unwrapping by region growing

The phase unwrapping problem consists in singling out an integer field whose values make the original wrapped phase field continuous. Even if in principle the problem is very simple—a direct integration of the wrapped phase field suffices—in the presence of noise and͞or undersampling, the solution is no longer unique and the direct integration methods usually fail to find an acceptable solution. This work presents what is to my knowledge a new unwrapping algorithm that attempts to find the solution by iteratively merging and shifting the continuous areas until a single region is built or no further moves are possible. Unlike the tile methods, the regions can have arbitrary shape and need not be single-connected so that, by removing the predefined size and shape constraint, the algorithm is very robust. The greater freedom of the regions’ shape makes their handling more problematic, so that certain implementation aspects, critical to algorithm performance, are presented here. Some unwrapping examples are also presented and memory requirements are discussed.