Underwater active polarization imaging for targets with complex polarization properties based on dual global estimation

Imaging for the targets with complex polarization properties tends to be a challenge in underwater polarization imaging, and its practical application is hindered by the reliance on human-computer interaction, background region and prior knowledge. In this paper, we analyze the underwater active polarization imaging model, and propose a novel underwater active polarization de-scattering method by globally estimating both degrees of polarization (DoPs) of the backscattered light and the target reflected light. The global DoP of the backscattered light is estimated by combining the Gaussian low-pass filtering with the mutual statistical independency of the target reflected light and the backscattered light, from which the global DoP of the target reflected light can be then obtained. The proposed method does not require background region in the underwater images, and the dual global estimation of DoPs is applicable for handling the complex targets with different polarization properties. The experimental results demonstrate that the backscattered light is well suppressed and the quality of underwater images with different scenes is effectively improved with or without background region by this method.