A robust single-shot phase extraction strategy via dual-channel hybrid phase-shifting framework

Two-step phase-shifting interferometry faces the challenge of balancing efficiency and accuracy in dynamic measurement. Traditional methods suffer from limited accuracy owing to inevitable filtering operations, which renders them highly vulnerable to noise interference. To address this issue, this paper proposes a single-shot two-step phase-shifting demodulation method based on a dual-channel hybrid phase-shifting network (DCH-PSN). Two interferograms with a fixed phase difference of π/2 are simultaneously acquired through two optical channels during a single temporal acquisition event and are used as dual-channel inputs, the method extracts fringe features separately through two encoder branches with independent parameters. Swin-Transformer modules are embedded at the low-resolution stage and the bottleneck layer, where the window and shifted-window self-attention mechanisms are adopted to capture long-range dependencies of interference fringes. The network-predicted π-shifted interferogram is combined with the two simultaneously measured interferograms to establish an equivalent three-step phase-shifting scheme, and phase extraction is finally accomplished via the three-step phase-shifting algorithm without iterative calculation. This method significantly improves the phase recovery accuracy and robustness to noise of the two-step phase-shifting method while maintaining high efficiency in dual-frame acquisition, providing a fast, high-precision phase extraction method for dynamic phase measurement.