Remove ambiguous zones using floodfill algorithm in digital photoelasticity

Abstract

Digital photoelasticity is a widely used technique for the full-field measurement of stress/strain distributions. However, ambiguous zones are present in the isochromatic phase map obtained with the commonly used ten-step phase shifting technique. Obtaining accurate isochromatic phase maps without wrapping can be challenging due to the presence of ambiguous zones. Existing methods to address this issue are complex and not fully automated. In this study, a novel approach is proposed to automatically and accurately remove the ambiguous zones using the Floodfill algorithm, an advanced digital image processing algorithm. The validity and robustness of the proposed method is demonstrated through benchmark tests on a disc and a ring subjected to diametral compression and a four-point bent beam, as well as a model with a complex geometry. The proposed method enhances the automation and simplicity of full-field stress/strain measurement in terms of the removal of ambiguous zones.