Ren Wenqi, Zhang Jingang, Xu Xiangyu, Ma Lin, Cao Xiaochun, Meng Gaofeng, Liu Wei
IEEE Trans Image Process. 2018 Oct 15. doi: 10.1109/TIP.2018.2876178.
Recent research have shown the potential of using convolutional neural networks (CNNs) to accomplish single image dehazing. In this work, we take one step further to explore the possibility of exploiting a network to perform haze removal for videos. Unlike single image dehazing, video based approaches can take advantage of the abundant information that exists across neighboring frames. In this work, assuming that a scene point yields highly correlated transmission values between adjacent video frames, we develop a deep learning solution for video dehazing, where a CNN is trained end-to-end to learn how to accumulate information across frames for transmission estimation. The estimated transmission map is subsequently used to recover a haze-free frame via atmospheric scattering model. In addition, as the semantic information of a scene provides a strong prior for image restoration, we propose to incorporate global semantic priors as input to regularize the transmission maps so that the estimated maps can be smooth in the regions of the same object and only discontinuous across the boundaries of different objects. To train this network, we generate a dataset consisted of synthetic hazy and haze-free videos for supervision based on the NYU depth dataset. We show that the features learned from this dataset are capable of removing haze that arises in outdoor scenes in a wide range of videos. Extensive experiments demonstrate that the proposed algorithm performs favorably against the state-of-the-art methods on both synthetic and real-world videos.
近期研究表明,使用卷积神经网络(CNN)实现单图像去雾具有潜力。在这项工作中,我们更进一步探索利用网络对视频进行去雾的可能性。与单图像去雾不同,基于视频的方法可以利用相邻帧中存在的丰富信息。在这项工作中,假设场景中的一个点在相邻视频帧之间产生高度相关的透射值,我们开发了一种用于视频去雾的深度学习解决方案,其中CNN经过端到端训练,以学习如何跨帧累积信息进行透射估计。随后,估计的透射图通过大气散射模型用于恢复无雾帧。此外,由于场景的语义信息为图像恢复提供了强大的先验信息,我们建议将全局语义先验作为输入纳入以正则化透射图,以便估计的图在同一物体区域内可以平滑,仅在不同物体的边界处不连续。为了训练这个网络,我们基于NYU深度数据集生成了一个由合成模糊和无雾视频组成的数据集用于监督。我们表明,从这个数据集中学习到的特征能够去除广泛视频中出现在户外场景的雾气。大量实验表明,所提出的算法在合成视频和真实世界视频上均优于现有方法。