Derivation of retardation phase in computer-aided photoelasticity by using carrier fringe phase shifting

Abstract

Previous phase-shifting schemes in computer-aided photoelasticity required the processing of six fringe patterns to derive the phase difference due to retardation. A technique in which a carrier fringe is used is demonstrated to reduce to four the number of fringe patterns required. The use of fewer fringe patterns lowers the computation time and the number of phase-step errors. The basis of the technique is outlined in detail, and experimental results are presented as well. © 1997 Optical Society of America.