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.