Phase recovery from a single undersampled interferogram.

A new method of phase determination from a single undersampled interferogram is described. Two low-fringe-density synthetic interferograms corresponding to the phase differences along orthogonal directions are obtained from neighboring pixels of the aliased measured data. The only assumption is that the illumination background, the modulation intensity, and the searched phase are smooth and continuous functions. The synthetic interferograms are demodulated by use of either standard frequency or spatial-domain procedures to obtain the phase differences. The phase is then recovered by integration of the phase differences with a least-squares method. The proposed method is demonstrated to be noise tolerant.