Dynamic interferometry with fringe projection for robust phase unwrapping and mapping error correction

This work presents an approach that combines dynamic interferometry with fringe projection to improve phase unwrapping and mapping error correction in the measurement of high-gradient flow fields. Traditional interferometry struggles with ray bending effects in strong refractive index gradients, leading to geometric distortions and phase unwrapping ambiguities. The proposed method projects a fringe pattern to extract ray deflection data, correcting mapping errors and providing additional phase information for robust unwrapping. This eliminates the need for spatial unwrapping of maps with dense 2π phase jumps or potential violations of the sampling criterion. Experimental validation demonstrates the efficiency of the phase unwrapping procedure and highlights its advantages over standard interferometry, making this approach highly suitable for real-time, high-accuracy characterization of supersonic flows, shock waves, and complex fluid dynamic environments.