Measurement of out-of-plane deformation by combination of speckle photography and speckle shearing interferometry
We measure the derivative of out-of-plane deformation in presence of large in-plane rigid body displacement (RBD) by a combination of Electronic Speckle-Shearing Pattern Interferometry (ESSPI) and speckle photography. We use digital speckle photography in order to compensate for the in-plane RBD and eliminate any decorrelation effects. ESSPI techniques are then applied to the compensated speckle images to obtain the derivative of the out-of-plane deformation. The method is tested on an aluminum plate subjected to simultaneous out-of-plane deformation and large in-plane RBD. The results indicate that the proposed method preserves the fringe contrast observed in ESSPI.