An underwater image restoration based on global polarization effects of underwater scene

Currently, most underwater polarization imaging methods assume that the backscattering is polarized and the reflected light of the target is unpolarized. In reality, this assumption is unreliable since both backscattering and reflected light contribute to polarization. Therefore, we propose an underwater image restoration method that combines the polarization effects of reflected light and backscattering. Firstly, Stokes vectors are used to automatically obtain polarization difference images. Based on the enhancement measure evaluation (EME) constraint, the initial estimate of backscattering is obtained. Then, an adaptive local optimization (ALO) method is designed to estimate global backscattering light. A variable factor is introduced for local optimization to obtain global backscattering. Finally, in order to optimize the system, particle swarm optimization (PSO) is introduced, which improves the processing speed of the system. The experimental results show that it is necessary to consider the polarization of the target during underwater polarization descattering, which not only has a good ability to eliminate scattering but also has an excellent effect on restoring target details.