A new method for photoelastic fringe analysis from a single image using elliptically polarized white light

A new two-dimensional photoelastic method for the analysis of fringe order and the principal direction of birefringence from a single image combining an elliptically polarized white light and color image processing is demonst rated. To determine fringe order, a database-search approach based on the p rimary color analysis is employed. After determining fringe order, the prin cipal direction of birefringence is obtained by solving a non-linear equati on. The equation of emerging light intensity is derived and the theory of t he proposed method is described. Then, the successful application of the me thod to photoelastic analysis is shown. It is emphasized that the proposed method can be applicable to time-varying phenomena since multiple exposures are not necessary for sufficient data acquisition for the completion of st ress analysis. (C) 1998 Elsevier Science Ltd. All rights reserved.