Multi-scale Attentive Image De-raining Networks via Neural Architecture Search

Abstract

Multi-scale architectures and attention modules have shown effectiveness in many deep learning-based image de-raining methods. However, manually designing and integrating these two components into a neural network requires a bulk of labor and extensive expertise. In this article, a high-performance multi-scale attentive neural architecture search (MANAS) framework is technically developed for image deraining. The proposed method formulates a new multi-scale attention search space with multiple flexible modules that are favorite to the image de-raining task. Under the search space, multi-scale attentive cells are built, which are further used to construct a powerful image de-raining network. The internal multiscale attentive architecture of the de-raining network is searched automatically through a gradient-based search algorithm, which avoids the daunting procedure of the manual design to some extent. Moreover, in order to obtain a robust image de-raining model, a practical and effective multi-to-one training strategy is also presented to allow the de-raining network to get sufficient background information from multiple rainy images with the same background scene, and meanwhile, multiple loss functions including external loss, internal loss, architecture regularization loss, and model complexity loss are jointly optimized to achieve robust de-raining performance and controllable model complexity. Extensive experimental results on both synthetic and realistic rainy images, as well as the down-stream vision applications (i.e., objection detection and segmentation) consistently demonstrate the superiority of our proposed method.Index Terms-Image de-raining, multi-scale attentive neural architecture search, multi-to-one training strategy. I. INTRODUCTIONW HEN people take photos in an outdoor environment, the captured images could suffer from visibility degradation owning to various bad weather conditions such as rain [1], [2], haze [3], [4], or snow [5]. Particularly, on a rainy day, the presence of rain can seriously degrade the visual quality of outdoor images, and as a result affects the visual authenticity of human perception and the performance