A pyramid non‐local enhanced residual dense network for single image de‐raining

Abstract Single image de‐raining based on convolutional neural network (CNN) has made considerable progress in recent years. However, usually the de‐rained result has dark artifacts and image textures tend to be over‐smoothed. In this paper, a pyramid non‐local enhanced residual dense network is proposed to reduce such distortion. Firstly, the down‐sampled images are input into the Laplacian pyramid, which can extract the overall and partial texture clues, and subsequently a set of images of different scales are produced. Secondly, these images are fed into a non‐local enhanced residual dense block, which can not only capture long‐distance dependencies of feature maps, but also fully utilizes the hierarchical features in every dense block, leading to high accuracy of rain streaks extraction and better preservation of image edge detail. Finally, the de‐rained image is gradually restored by Gaussian reconstruction pyramid. Experimental results on both synthetic data and real‐world data show that the artifacts distortion is obviously reduced by the proposed network. And the quality of de‐rained image is significantly improved compared with the state‐of‐the‐art methods.