Dynamic out-of-plane measurements using a speckle interferometer with a pixelated polarization camera

Abstract This work presents a dynamic electronic speckle pattern interferometry (ESPI) system with out-of-plane sensitivity based on a pixelated polarization camera. The approach employs polarization-encoded phase-shifting interferometry, enabling the simultaneous acquisition of multiple phase-shifted speckle interferograms and allowing the temporal tracking of deformation fields induced by mechanical loading. From the four polarization-resolved interference patterns, the phase is retrieved using a Fourier-based phase demodulation approach, from which the out-of-plane displacement field is reconstructed. Experimental results obtained on galvanized steel plates, including samples with and without structural defects such as cracks, demonstrate the capability of the method to resolve spatial variations in dynamic deformation, which were introduced by a piezoelectric actuator to assess the temporal stability and repeatability of the proposed system. These results indicate that the proposed approach is suitable for non-destructive evaluation and dynamic deformation monitoring of metallic components under mechanical stress.