On accounting for speckle extinction via DIC and PCA

Rafael Vargas (1, 2) , R B Canto (1) , François Hild (2) , Stéphane Roux (2)

1 UFSCar - Federal University of São Carlos
2 LMPS - Laboratoire de Mécanique Paris-Saclay

Digital Image Correlation (DIC) is a full-field measurement technique that generally relies on brightness conservation principles. This work aims to analyze cases in which the speckle pattern vanished after heating, thereby severely altering the brightness. Sets of images acquired during \textcolor{red}{\bf 6} experiments were registered and then used to obtain optimal sets of reference images for each time step via Principal Component Analysis (PCA). The proposed methodology significantly reduced the gray level residuals and provided insight into brightness variations that occurred in the analyzed cases. It was possible to study cases with severe speckle pattern changes by updating the reference image when standard DIC did not converge and using the PCA methodology to obtain optimal reference states.

Mots clés: Brightness conservation; Digital Image Correlation (DIC); High temperature; Principal Component Analysis (PCA); Wedge Splitting Test (WST)

Domaines: Mécanique des matériaux [physics.class-ph]

Rafael Vargas, R B Canto, François Hild, Stéphane Roux. On accounting for speckle extinction via DIC and PCA. Optics and Lasers in Engineering, 2022, 149, pp.106813. ⟨10.1016/j.optlaseng.2021.106813⟩. ⟨hal-03358220⟩