水面高动态范围场景分焦平面偏振成像的自适应增强方法  

Adaptive Enhancement Methods for Division of Focal Plane Polarimetric Imaging of Water Surface High Dynamic Range Scenes

作　　者：王美淑 杨建国 金伟其 裘溯 王艺学 Wang Meishu;Yang Jianguo;Jin Weiqi;Qiu Su;Wang Yixue(MOE Key Laboratory of Optoelectronic Imaging Technology and System,School of Optics and Photonics,Beijing Institute of Technology,Beijing 100081,China;Guangdong Key Laboratory of Intelligent Detection in Complex Environment of Aerospace,Land,and Sea,Zhuhai 519088,Guangdong,China)

机构地区：[1]北京理工大学光电学院光电成像技术与系统教育部重点实验室,北京100081 [2]广东省“天临空地海”复杂环境智能探测重点实验室,广东珠海519088

出　　处：《光学学报》2024年第18期213-223,共11页Acta Optica Sinica

基　　金：国家自然科学基金面上项目(62171024)。

摘　　要：在户外真实场景的水域成像过程中,太阳光经水面反射会形成强部分偏振耀光,水域场景通常伴随亮度变化范围大难以清晰成像的问题。本文提出了一种名为“WP-HDR”的基于分焦平面可见光偏振相机抑制太阳耀光实现水面场景高动态范围成像的方法。通过偏振处理抑制高强度水面耀光,Otsu算法与滤波配合实现对区域的分割,最后通过自适应线性融合实现对过暗部分的增强。实际场景的实验结果表明,处理后得到的高动态范围图像中,水面耀光得到了有效的抑制,背景和目标细节的轮廓信息更清晰,复合对比度、标准差和平均梯度均得到显著改善。本文提出的复合对比度可同时体现耀光抑制程度和暗目标清晰化程度,在本文的实验结果中最高可提升三倍。实验证明本文所提方法可用于强反射干扰下的水面成像以及水域目标的识别。Objective China has vast water areas and a long coastline.Unlike sensor detection technology,imaging detection technology provides a direct display of water conditions through non-contact remote sensing images,which is of great significance for the development of water economy and water-related scientific research.In an outdoor environment,sunlight reflected on the water surface forms strong polarized glints and affects the water brightness,making it extreme challenging to obtain clear images and affecting water surface imaging.This leads to large-area pixel saturation and pixel information loss in imaging detector.Therefore,high dynamic range(HDR)imaging is required for water surface scenes.Fully utilizing polarization information can provide new insights for HDR technology in water scenes.Although glint on the water surface exhibits distinct polarization characteristics,polarized images can reduce such impacts on the rough water surface.In this study,we report a method called water surface polarization HDR(WP-HDR),which utilizes a division of focal plane(DOFP)system to suppress sunlight glints and achieve HDR imaging of water scenes.Real-time water surface HDR imaging is achieved based on the DOFP system.We hope that our basic strategy and findings can contribute to applications such as water environment protection and aquatic meteorological monitoring.Methods We focus on the polarization water surface HDR method and use the DOFP system to obtain four images in polarization directions in 0°,45°,90°,and 135°,respectively.Firstly,based on the principles of polarization imaging and Stokes vector calculation,we process a frame of an image from the DOFP system to obtain an image in any polarization direction.Through polarization processing,we suppress the high-intensity glints on the water surface,obtaining the maximum and minimum grayscale images simultaneously,Imax and Imin.We then use the Otsu segmentation method and filtering to segment Imax and identify the regions of interest Idark for enhancement.Finally,

关 键 词：图像处理 大气与海洋光学 水面偏振成像 高动态范围成像 自适应线性增强 

分 类 号：O436.3[机械工程—光学工程]