基于光源区域自适应的夜间去雾方法  

Nighttime Image Dehazing Method Based on Adaptive Light Source Region

作　　者：王同森 史勤忠 王得法 董硕 杨国为[1] 于腾[1] WANG Tong-sen;SHI Qin-zhong;WANG De-fa;DONG Shuo;YANG Guo-wei;YU Teng(College of Electronic Information,Qingdao University,Qingdao,Shandong 266071,China;College of Computing,Qingdao University,Qingdao,Shandong 266071,China)

机构地区：[1]青岛大学电子信息学院,山东青岛266071 [2]青岛大学计算机学院,山东青岛266071

出　　处：《计算机科学》2021年第S02期327-333,共7页Computer Science

基　　金：国家重点研发计划项目(2017YFC080-4000);国家自然科学基金项目(61772277,61873071)。

摘　　要：夜间有雾图像会导致图像质量下降,主要体现在夜间有雾图像光照不均、对比度较低且色偏严重,而人工光源的存在更是使得环境光呈现出不均匀性。现有的主流算法主要是针对白天图像进行处理,并不适用于夜间场景去雾处理,导致夜间去雾难度加大。针对上述问题,通过深入分析夜间有雾图像的成像特点,提出了一种新的夜间图像去雾算法。针对夜间有雾图像的色偏问题,提出了改进的暗通道先验算法(MRP)进行颜色校正,该方法单独操作每一个颜色通道进行颜色校正,从而可以减少由MRP引起的光源区域周围的光晕效应;针对夜间场景环境光不均匀性的特点,提出了基于有雾图像低频分量的最小-最大值滤波方法,以此来实现局部环境光的估计;针对最大反射率先验(DCP)估计透射率在光源处失效的问题,提出了一种基于光源区域自适应的透射率估计算法。实验结果表明,该算法在抑制光晕和光源区域发散的同时,能够较好地重现暗部细节,恢复图像具有较好的亮度和对比度,且色彩自然。相比暗通道先验,所提方法的峰值信噪比(PSNR)与结构相似性值(SSIM)平均提升了81.8%和26.5%。Nighttime hazy image will cause image quality degradation,mainly reflected in the uneven illumination,low contrast and serious color deviation of nighttime hazy image,and artificial light source makes the ambient light nonuniformity.The existing mainstream algorithms are mainly for daytime image processing,but are not suitable for night scene dehazing processing.This makes night dehazing more difficult.In order to solve the above problems,this paper analyzes the imaging features of night image with fog and proposes a new night image dehazing algorithm.Aiming at the problem of color deviation of hazy images at night,this paper proposes an improved maximum reflectance prior algorithm(MRP)for color correction.This method operates each color channel separately for color correction,so as to reduce the halo effect around the light source area caused by MRP.As for the characteristics of nonuniformity of ambient light in night scene,a minimum reflectance prior algorithm based on low frequency component of hazy images is proposed.In order to solve the problem that the dark channel prior(DCP)estimation of transmittance fails at the light source,we propose a region adaptive algorithm of transmittance estimation based on the light source.The experimental results show that the proposed algorithm can suppress the halo and the divergence of the light source area.At the same time,it can better reproduce the dark details and restore the image with better brightness.

关 键 词：夜间图像去雾 图像去雾 图像复原 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]