Abstract
To address the challenges of low target contrast and severe scattering noise in turbid media imaging, this paper proposes an underwater active imaging method that integrates range-gated and polarization-difference joint modulation. By establishing a physical model of spatio-polarimetric joint modulation, we systematically analyze the differences in both depolarization characteristics and time-delay properties between target-reflected light and backscattered light. A dual mechanism combining time gating for primary scattering suppression and polarization difference for residual noise elimination is utilized to achieve high-precision separation and enhancement of the target signal. Through a combination of MATLAB simulations and experimental studies, using fat emulsion solutions to emulate turbid water and a 450 nm laser as the light source, key parameters including the medium absorption coefficient and scattering intensity were adjusted to identify system-sensitive parameters and optimization strategies. Results demonstrate that the proposed polarization-difference range-gated imaging method outperforms conventional imaging approaches in both image signal-to-noise ratio and target contrast, confirming its effectiveness and advancement for target detection in turbid media. This work provides a new perspective for high-resolution optical imaging in complex underwater environments.