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

• Published in: NDT & E international : independent nondestructive testing and evaluation 2019-04, Vol.103, p.173-176
• Main Author: Wang, K.F.
• Format: Article
• Language: English
• Subjects: Internal defect; Morphological operation; Out-of-plane deformation; Phase-shifting digital speckle pattern interferometry; Wrapped phase
• ISSN: 0963-8695; 1879-1174
• DOI: 10.1016/j.ndteint.2019.03.002

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. •A novel method used for detection of internal defects is proposed for the first time.•The proposed method is valid for internal defects with boundary of arbitrary shape.•The proposed method is based on morphological opening, filling and binarizing.•The proposed method can detect internal defects directly from the wrapped phase.•The propose method does not require unwrapping of phase and denoising of fringes.