Quantitative detection of internal defects based on morphological opening, filling and binarizing operations on wrapped phase of out-of-plane deformation in digital speckle pattern interferometry

Abstract

A novel method used for quantitative detection of internal defects with boundary of arbitrary shape is proposed in this paper for the first time. This method can be used to determine accurately the location and size of internal defects based on sequential morphological opening, filling and binarizing operations on the wrapped phase of out-of-plane deformation in phase-shifting digital speckle pattern interferometry. Because internal defects are detected directly from a wrapped phase rather than an unwrapped phase, the method proposed in this paper requires neither unwrapping of wrapped phase nor denoising of interference fringes when used for quantitative detection of internal defects. Theoretical analysis, numerical simulation, experimental verification and error calculation are presented in this paper.