结合天空分割和金字塔融合的多尺度图像去雾  

Multiscale Image Dehazing Method Combining Sky Segmentation and Pyramid Fusion

作　　者：肖新杰 李志伟[1,2] 张楠楠 孙雨晴 周武能 XIAO Xinjie;LI Zhiwei;ZHANG Nannan;SUN Yuqing;ZHOU Wuneng(College of Electronic and Electrical Engineering,Shanghai University of Engineering Science,Shanghai 201620,China;College of Information Science and Technology,Donghua University,Shanghai 201620,China)

机构地区：[1]上海工程技术大学电子电气工程学院,上海201620 [2]东华大学信息科学与技术学院,上海201620

出　　处：《计算机工程》2023年第12期205-213,223,共10页Computer Engineering

基　　金：国家自然科学基金(61705127);上海工程技术大学检测技术与自动化装置学科学位点建设项目(19XXK003)。

摘　　要：针对传统图像去雾方法存在对比度下降、色调偏暗和过度曝光的问题,提出一种结合天空分割和金字塔融合的多尺度图像去雾方法。利用含有梯度的分水岭算法分割天空区域,使用均值滤波计算天空区域得分,运用最高得分所对应最亮天空区域的平均灰度值获取更准确的大气光值。为了规避传统图像去雾方法估计的透射率强度值偏低或整体强度值偏高造成的负面影响,提出一种基于图像金字塔的多尺度透射率融合方法,通过拉普拉斯图像金字塔分别将暗通道先验和具有曝光特性的图像去雾算法估计的透射率图分解为多个尺度,采用感知融合方法融合拉普拉斯图像金字塔的每一层,重建融合透射率图的高斯图像金字塔,高斯图像金字塔的最底层即为融合后的透射率图;最后将所估计的大气光值和融合透射率代入大气散射模型,复原无雾图像。实验结果表明,所提去雾方法能够避免所复原无雾图像中存在的对比度下降、色调偏暗和过度曝光的问题,在SOTS室内外合成测试集上的PSNR和SSIM分别比排名第2的对比方法高出8.13%、0.59%和1.75%、1.57%。A multiscale image dehazing method that combines sky segmentation and pyramid fusion is proposed to address contrast degradation,dark tones,and overexposure in traditional image dehazing methods.First,the method uses a watershed algorithm with gradients to segment the sky region,calculates the sky region score using mean filtering,and uses the average gray value of the brightest sky region corresponding to the highest score as the atmospheric light value.Second,to avoid the negative impacts caused by the low or high overall intensity values of the estimated transmissions by traditional image dehazing methods,a multiscale transmission fusion method based on image pyramid is proposed,using Laplacian image pyramid to decompose the transmission map estimated by the dark channel a priori and the image dehazing algorithm with exposure characteristics into multiple scales respectively,using perceptual fusion method to fuse each layer of the Laplacian image pyramid,and then reconstructing the Gaussian image pyramid of the fused transmission map,and the bottom layer of the Gaussian image pyramid is the fused transmission map.Finally,the estimated atmospheric light value and fused transmission are fed into the atmospheric scattering model to recover the dehazed image.Experiments show that the proposed dehazing method can avoid contrast degradation,dark tones,and overexposure in dehazed images.The PSNR and SSIM on the SOTS indoor and outdoor synthetic test sets are 8.13%,0.59%,and 1.75%,1.57%higher than those of the second-ranked comparison method.

关 键 词：图像去雾 天空分割 透射率融合 大气光值 图像金字塔 

分 类 号：TP391.4[自动化与计算机技术—计算机应用技术]