Uncertainty Modeling of the Transmission Map for Single Image Dehazing

Bokang Wang, Qian Ning, Fangfang Wu, Xin Li, Weisheng Dong, Guangming Shi

Abstract: Despite rapid progress of end-to-end optimization for single-image dehazing, a long-standing open problem is the non-homogenous haze, at the core of the differences between synthetic hazy images and real hazy images. The atmospheric scattering model (ASM) has been widely adopted to model the degradation process of haze images but based on the assumption of homogeneous haze. In realistic scenarios, non-homogeneous haze often makes it more difficult to estimate the transmission map in ASM, resulting in undesired artifacts in the restored images. To address the issue of non-homogeneous haze, we propose to model the uncertainty in the estimation of the transmission map and develop a spatially adaptive learning module for ASM correction. Specifically, we present an approach to enhancing the well-known Dark Channel prior (DCP) by relaxing the constraint with the transmission map in the DCP-net. Assuming the availability of paired training data, we have developed a strategy to address vulnerability in the DCP, leading to a more accurate estimation of the transmission map. Then, we explore the uncertainty between the estimated transmission map and target transmission map (Ground Truth) to reformulate the ASM for the presence of non-homogeneous haze. A robust and accurate estimated transmission map can boost the final dehazing performance of our DCP-net. Experiments on three popular synthetic and real non-homogeneous datasets show that our proposed approach has achieved better results on both synthetic scenes and real non-homogeneous scenes. The code is available at https://see.xidian.edu.cn/faculty/wsdong/Projects/Projects/project_dehazing_TCSVT2024.htm