影响水下成像质量的核心因素是后向散射光的干扰。偏振差分水下成像技术能够显著抑制后向散射光,是在水下散射环境中获取清晰图像的有效方法。传统的偏振差分方法是基于两个正交偏振方向上的偏振图像进行差分的,该方法虽然对后向散射光有明显的抑制效果,但其调制自由度低,限制了成像质量的进一步提升。针对这一问题,提出一种改进型偏振差分水下成像方法,该方法基于两个最优偏振方向的偏振图像进行差分,并通过引入差分项的权重系数,最终实现具有三个自由度的偏振差分水下成像。实验结果显示,该方法相对于传统的偏振差分成像方法,可更好地抑制后向散射光、凸显物体信号光,最终实现了更高质量的水下清晰成像。

The technology of underwater polarization difference imaging can significantly suppress the backscattered light, the key factor affecting the quality of underwater imaging. Therefore, it is an effective method to obtain clear images in the underwater scattering environment. Traditional polarization difference methods are based on the polarization images at two orthogonal polarization directions and have obvious effects on suppressing the backscattered light. However, the corresponding degree of modulation freedom is low, which limits the further improvement of imaging quality. To solve this problem, we proposed an improved method of underwater polarization difference imaging in this paper. After the difference of polarization images in two optimal polarization directions and the introduction of the weight coefficient for the difference item, this method could realize the underwater polarization difference imaging with three degrees of freedom. The experimental results show that compared with the traditional polarization difference imaging, the proposed method can better restrain the backscattered light, highlight the signal light of the objects, and finally achieve the underwater clear imaging with higher quality.