Yu Tao, Wang Xiaolei, Xi Sixing, Mu Quanquan, Zhu Zhuqing
Opt Express. 2023 Jan 2;31(1):459-468. doi: 10.1364/OE.477243.
Polarization imaging techniques have more prominent advantages for imaging in strongly scattered media. Previous de-scattering methods of polarization imaging usually require the priori information of the background region, and rarely consider the effect of non-uniformity of the optical field on image recovery, which not only reduces the processing speed of imaging but also introduces errors in image recovery, especially for moving targets in complex scattering environments. In this paper, we propose a turbid underwater moving image recovery method based on the global estimation of the intensity and the degree of polarization (DOP) of the backscattered light, combined with polarization-relation histogram processing techniques. The full spatial distribution of the intensity and the DOP of the backscattered light are obtained by using frequency domain analysis and filtering. Besides, a threshold factor is set in the frequency domain low-pass filter, which is used to adjust the execution region of the filter, which effectively reduces the error in image recovery caused by estimating the DOP of the backscattered light as a constant in traditional methods with non-uniform illumination. Meanwhile, our method requires no human-computer interaction, which effectively solves the drawbacks that the moving target is difficult to be recovered by traditional methods. Experimental studies were conducted on static and moving targets under turbid water, and satisfactory image recovery quality is achieved.
偏振成像技术在强散射介质成像方面具有更为突出的优势。以往的偏振成像去散射方法通常需要背景区域的先验信息，且很少考虑光场不均匀性对图像恢复的影响，这不仅降低了成像的处理速度，还在图像恢复中引入误差，特别是对于复杂散射环境中的移动目标。本文提出一种基于后向散射光强度和偏振度（DOP）全局估计，并结合偏振关系直方图处理技术的浑浊水下运动图像恢复方法。利用频域分析和滤波获取后向散射光强度和DOP的完整空间分布。此外，在频域低通滤波器中设置一个阈值因子，用于调整滤波器的执行区域，有效减少了传统方法中在非均匀照明下将后向散射光的DOP估计为常数而导致的图像恢复误差。同时，我们的方法无需人机交互，有效解决了传统方法难以恢复移动目标的缺点。在浑浊水下对静态和移动目标进行了实验研究，取得了令人满意的图像恢复质量。
