Spatial-temporal hybrid retrievals of photoelastic phase map

Abstract

A spatial-temporal hybrid approach for retrieving the isoclinic and isochromatic phase messages of practical photoelastic problems is proposed. With the aid of the proposed method, the undefined problem caused by the null term of denominator in the phase map calculation as well as the ambiguity zone problem during temporal phase unwrapping can be respectively solved. Four plane polariscope phase stepping frames are utilized first to correctly restore the isoclinic data of the test sample, of which a white lighting source with full color CCD is used for the colored photoelastic interferograms recording to circumvent the undefined problem. Then after, the retrieved isoclinic is further substituted into the isochromatic formulation to decouple its isoclinic dependence and get a decoupled isochromatic phase map for the following spatial phase unwrapping without much difficulty. In addition, a temporal retrieving of isochromatic phase map is also implemented too; a different wavelength approach is applied to check the performance of the proposed algorithm. It is proved that the robustness and effectiveness of the proposed method are both acceptable.