Two-dimensional phase unwrapping of subsampled phase-shifted interferograms

A novel procedure for phase recovery from undersampled phase-shifted interferograms is described. First, synthetic interferograms are used to calculate the wrapped phase differences along two orthogonal directions. Second, they are unwrapped to recover the true Laplacian of the phase. The final step is to integrate the unwrapped phase differences to obtain the required phase. This method may be used with either path-independent or path-dependent phase unwrapping algorithms. The technique overcomes the sensitivity to noise of previous algorithms when low pass filtering techniques are applied during the calculation of the phase differences and least square methods are employed in the final step of phase integration.