Unveiling the role of scattering medium: how physical properties govern resolution and contrast in speckle-correlation imaging

In the field of high-resolution optical imaging through complex scattering media, speckle-correlation technology (SCT) faces a critical challenge: the multiple scattering effects induced by medium inhomogeneity (e.g., refractive index distribution, particle arrangement) disrupt the speckle information encoding mechanism. When the scattering complexity exceeds the imaging system’s critical threshold, nonlinear degradation in imaging resolution and contrast occurs. To elucidate the physical mechanisms behind SCT performance deterioration and propose novel quantitative evaluation methods, this study introduces a dual-correlation-path mathematical model, establishing a relationship between scattering medium complexity metrics and the imaging system’s point spread function (PSF). The model analyzes the mathematical connections between scattering media with diverse physical properties and PSF characteristics, while also linking imaging targets to PSF through a medium-complexity-driven framework. A complexity metric is proposed as a discriminant for the permissible threshold of SCT-based imaging systems. Numerical modeling and imaging experiments quantitatively demonstrate the significant influence of scattering medium properties on resolution and contrast, alongside the sensitivity of imaging system thresholds to target complexity. This research provides new insights for high-fidelity imaging through dynamically complex scattering media.