基于斯托克斯参量的水下主动偏振去散射研究

Underwater Active Polarization Descattering Based on Stokes Vectors

摘要:

受浑浊水体自身吸收与微颗粒散射的影响，水下光学成像面临成像距离短、像质差的问题。本文将一种改进的主动偏振成像模型引入到水下成像去散射过程中，有效提升了探测的清晰度。相比于被动偏振成像模型，主动光源可以对入射光并 进行偏振调制，由此可以充分利用目标反射光与介质光的偏振特征差异进行分离选通。改进的主动去散射模型基于反射型目标反射光的偏振共模抑制效应，充分利用偏振斯托克矢参量S2分量，屏蔽目标信息干扰，进而准确重建介质光偏振度分布。以此同时将水下图像评价指标contrast作为反馈参量以实现背景噪声的最大化滤除。不同浑浊度水体中多目标类型的成像实验表明本文所提出的新方法相比于经典主动偏振成像方法，在噪声抑制与成像质量方面均 实现显著提升，特别是强散射环境下的成像contrast提升超过2倍以上。该项工作进一步拓展了利用偏振信息进行水下图像去散射的可行性，也证明了主动偏振成像技术在散射水体目标探测的重要应用价值。

Abstract:

Affected by the scattering of micro-particles in turbid water, optical imaging faces the problems of short imaging distance and poor image quality. In this paper, an improved active polarization imaging method is introduced into the descattering process to achieve higher imaging contrast. Compared with the passive polarization imaging model, the introduction of an active light source can perform polarization modulation on the incident light, which better serves the underwater optical transmission model to separate and solve the target information. For the first time, the S2 component of Stokes vectors based on the common mode suppression is used to eliminate the interference of the target information. Therefore, the polarization degree of backscattered light is accurately reconstructed. Meanwhile, introducing contrast as feedback optimization is to achieve determination of optimal parameters. The imaging experiments with different types of targets prove the effectiveness of the method under various turbidities water. Especially at strong scattering water, the imaging contrast is improved by more than 2 times. It is of great scientific value to introduce the polarization information into the enhancement and restoration of the target information.