DERIVATION OF RETARDATION PHASE IN COMPUTER-AIDED PHOTOELASTICITY BY USING CARRIER FRINGE PHASE-SHIFTING

Previous phase-shifting schemes in computer-aided photoelasticity requ ired the processing of six fringe patterns to derive the phase differe nce due to retardation. A technique in which a carrier fringe is used is demonstrated to reduce to four the number of fringe patterns requir ed. The use of fewer fringe patterns lowers the computation time and t he number of phase-step errors. The basis of the technique is outlined in detail, and experimental results are presented as well. (C) 1997 O ptical Society of America.