Research on target enhancement in turbid media based on range-gated polarization difference imaging.

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.