Two-Step Image Dehazing with Intra-domain and Inter-domain Adaption.

Recently, image dehazing task has achieved remarkable progress by convolutional neural network. However, those approaches mostly treat haze removal as a one-to-one problem and ignore the intra-domain gap. Therefore, haze distribution shift of the same scene images is not handled well. Also, dehazing models trained on the labeled synthetic datasets mostly suffer from performance degradation when tested on the unlabeled real datasets due to the inter-domain gap. Although some previous works apply translation network to bridge the synthetic domain and the real domain, the intra-domain gap still exists and affects the inter-domain adaption. In this work, we propose a novel Two-Step Dehazing Network (TSDN) to minimize the intra-domain gap and the inter-domain gap. First, we propose a multi-to-one dehazing network to eliminate the haze distribution shift of images within the synthetic domain. Then, we conduct an inter-domain adaption between the synthetic domain and the real domain based on the aligned synthetic features. Extensive experimental results demonstrate that our framework performs favorably against the state-of-the-art algorithms both on the synthetic datasets and the real datasets.