Dual-wavelength multi-intensity phase retrieval utilizing adaptive wavelength calibration

Dual-wavelength multi-intensity phase retrieval extends the unambiguous measurement range of quantitative phase imaging by exploiting the synthetic wavelength. However, wavelength deviations and temporal drifts inherent in low-cost laser sources lead to mismatches in the diffraction model, thereby degrading reconstruction accuracy. To reduce system cost while ensuring accurate measurement, an Axial Distance Error Wavelength Self-Calibration (ADE-WSC) phase retrieval method is proposed. The proposed method incorporates an adaptive wavelength calibration strategy into a parallel Amplitude-Phase Retrieval (APR) framework. By utilizing the equivalence between wavelength variation and axial propagation distance under equally spaced measurements, the equivalent axial spacing of each measurement plane is adaptively optimized by maximizing the structural similarity index (SSIM). The iterative optimization simultaneously compensates for axial distance errors and estimates the true illumination wavelengths. Numerical simulations and experiments demonstrate that ADE-WSC accurately corrects the wavelengths and significantly reduces reconstruction errors, leading to more robust dual-wavelength phase retrieval under non-ideal illumination conditions. The proposed framework offers a practical and cost-effective solution for large-range quantitative phase imaging with low-cost, wavelength-unstable laser sources.