2D phase unwrapping algorithms

Implementations of the phase quality path following method and Goldstein's branch cut method.

Description

Two 2D phase unwrapping approaches are included:
1. Phase quality guided path following method.
2. Goldstein's branch cut method.

The algorithms are described in:
D. C. Ghiglia and M. D. Pritt, Two-Dimensional Phase Unwrapping:
Theory, Algorithms and Software. New York: Wiley-Interscience, 1998.

• Acknowledgements: This submission has inspired the following:; NF2FF
• MATLAB release: MATLAB 7.5 (R2007b)

[Deva]

Thanks for the contribution!! It is a much more elegant code than the one I was attempting to write from the pseudocode!

As I was testing out the code, I noticed that the algorithm does not go back and unwrap the branch cut pixels, as is described in Ghiglia and Pritt. Perhaps that would be a good addition to the next version?

[Hex]

 

[Eric]

Useful for unwrapping small images, but not for large images. A 510x510 array took 25 minutes on my machine. The following improvements need to be made for larger arrays:

1. Implement the "postponed" list described in Ghiglia and Pritt.
2. Avoid using Matlab's unwrap() function for unwrapping a length-two vector. Instead use Itoh's Method for a length 2 vector explicitly:
           D = psi(2)-psi(1);
           delta = atan2(sin(D),cos(D);
           phi = psi(1) + delta;
3. Resize matrices as vectors

This yields about 20X speed improvement for the 510x510 array size.