Separation of isoclinics and isochromatics from photoelastic data with a regularized phase-tracking technique

We present the application of a regularization algorithm to the processing of photoelastic fringe patterns. The method used is a modified regularized phase-tracking (RPT) algorithm applied to phase-shifted images. In particular, we present an algorithm for isoclinic-isochromatic separation that uses only five images. In the case of isoclinics the method can deal with problems associated with modulation of isochromatics and with isotropic points by means of a modified cost functional. With respect to the isochromatics the problems associated with regions of high fringe density are solved in a robust way by the unmodified RPT algorithm by use of the modulation information. The performance of the method is discussed, and experimental results are presented. (C) 2000 Optical Society of America. OCIS codes: 100.2650, 120.5050, 260.5430.