Multi-shear strategy for high-sensitivity and wide-range shearography

This Letter presents a multi-shear strategy to resolve the trade-off between sensitivity and measurement range in shearography. The method progressively unwraps dense fringes using wrapped phases with varying fringe densities, guided by theoretical design criteria. Simulations and experiments verify an extended measurable gradient range while preserving large-shear sensitivity. Compared with the RPUA single-frame baseline, the method effectively improves the experimental measurement range by 94.8% in the large-shear case. Therefore, the proposed strategy successfully tracks the reliable small-shear range, offering a robust framework for high-sensitivity, wide-range shearography.