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(n ²) to O(n log ₂ n), where n is the number of pixels in the phase map. Typical 256×256 phase maps from magnetic resonance imaging can be unwrapped in seconds, compared with tens of minutes with the O(n ²) implementation. This makes the pixel-level MST method time efficient and practically attractive.