Orthogonal polynomials and global optimization based demodulation of two-shot fringe patterns

We propose a simple yet effective phase demodulation algorithm for two-shot fringe patterns with random phase shifts. The phase to be recovered is decomposed into a linear combination of finite terms of orthogonal polynomials; the expansion coefficients and the phase shift are exhaustively searched through global optimization. The technique is insensitive to noise or defects, and is capable of retrieving phase from low fringe-number interferograms. The retrieved phase is continuous and no further phase unwrapping process is required. The method is expected to be promising to process interferograms with regular fringes.