Phase retrieval algorithm in spatial phase-shift shearography based on dynamic mode decomposition

Spatial phase-shift shearography is an important non-destructive technique that offers low experimental setup complexity and dynamic event measurement capability. Phase retrieval from the specklegram/shearogram forms the most critical part of the shearographic measurement process. In the present work, we propose a dynamic mode decomposition (DMD)-based algorithm for phase retrieval in spatial phase-shift shearography. The DMD offers a promising alternative to traditional Fourier transform (FT)-based phase extraction in shearography, particularly addressing the challenge of spectral overlap. The phase estimation performance of the proposed DMD-based algorithm is experimentally validated for varying aperture sizes and shear amounts. A performance comparison with the FT and Stoilov algorithms is presented, indicating the practical applicability of the proposed algorithm.