The spatial orientation of the fringe has been demonstrated to be a key point in the reliable phase demodulation from a single n-dimensional fringe pattern regardless of the frequency spectrum of the signal. The recently introduced general n-dimensional quadrature transform (GQT) makes explicit the importance of the fringe orientation in the demodulation process. The GQT is a quadrature operator that transforms cosphi into −sin phi - where phi is the modulating phase - and it is composed of two terms: an orientation factor directly related to the fringe's spatial orientation and an isotropic n-dimensional generalization of the one-dimensional Hilbert transform. We present a method for the determination of the orientation factor in a general n-dimensional case and its application to the demodulation of a single fringe pattern by the GQT. We have tested the algorithm with simulated as well as real photoelastic fringe patterns with good results.
© 2005 Optical Society of America
(100.0100) Image processing : Image processing
(100.2650) Image processing : Fringe analysis
(100.6890) Image processing : Three-dimensional image processing
(120.5050) Instrumentation, measurement, and metrology : Phase measurement
J. Antonio Quiroga, Manuel Servin, J. Luis Marroquin, and Daniel Crespo, "Estimation of the orientation term of the general quadrature transform from a single n-dimensional fringe pattern," J. Opt. Soc. Am. A 22, 439-444 (2005)