A fast implementation of the minimum spanning tree method for phase unwrapping.

A new implementation of the minimum spanning tree (MST) phase unwrapping method is presented. The time complexity of the MST method is reduced from O(n2) to O(n log2 n), where n is the number of pixels in the phase map. Typical 256 x 256 phase maps from magnetic resonance imaging can be unwrapped in seconds, compared with tens of minutes with the O(n2) implementation. This makes the pixel-level MST method time efficient and practically attractive. Index Terms-Image processing, magnetic resonance imaging, medical imaging, phase unwrapping.