Stroboscopic shearography techniques, including double pulse shearography, are able to image transient Lamb waves to support non-destructive testing of structures and materials. The amplitude of the signal measured with these techniques is known to depend on optical shear distance and direction but the experimental demonstrations presented in the literature are limited. We present improved experimental results that show the dependence of signal amplitude on shear distance. By carefully selecting the shear distance, we are able to visualize a defect with shearographic measurement of transient Lamb waves.

Shearography and electronic speckle pattern interferometry (ESPI) have historically been developed in limited collaboration. Both techniques have a significant entry barrier for new researchers to get reliable results. The situation is even worse regarding data and code availability: only three documented and publicly available shearography datasets and very limited open software realisations exist. The data sharing aspect gets more critical. First, AI developments are well reported, while only two datasets were published. Second, developments in phase processing are reported without publicly available code. This limits reproducing and validating the results. Following an example from open data challenges in digital image correlation (DIC), this presentation highlights the Open Science issues and proposes three shearography datasets with inspection of composites. This presentation intends to initiate a discussion in the field that could lead to better practices on data and code sharing.

We use the recently developed wave model of geometric phase to track the continuous evolution of geometric phase as a wave propagates through optical elements and throughout an optical system. By working directly with the wave properties, we encounter a natural explanation of why the conventional Poincaré sphere solid angle method must use geodesic paths rather than the physical paths of the polarization state—the “geodesic rule”—and show that the existing rules for the solid angle algorithm are incomplete. Finally, we use the physical model to clarify the differences between the Pancharatnam connection and the geometric phase of a wave.