Object detection under adverse weather conditions remains a challenging problem to date. To address this problem, a joint image and feature enhancement method called JE-YOLO is proposed. Firstly, a lightweight image enhancement network is used to enhance the low-quality image captured under adverse weather conditions. Secondly, to provide rich information for detection, two detection backbones are applied in parallel to extract features from both the low-quality image and its enhanced result. Afterwards, the extracted features are further enhanced by a foreground-guided feature refinement module (FFRM), which introduces a task-driven attention mechanism and explores inter-layer correlation. Finally, the enhanced features from different branches are fused by the adaptive multi-branch weighting (AMW) strategy, and then fed to the neck and head of detector. Experiments are carried out on both the low-light and foggy conditions, and the results demonstrate that compared with state-of-the-art (SOTA) methods, the proposed JE-YOLO is able to achieve the highest accuracy of detection in all cases. Code will be available at https://github.com/Murray-Yin/JE-YOLO.

Detecting objects on low-resolution (LR) images is a challenging task, as small structures and details contained in LR images are insufficient. To improve the detection accuracy on LR images, a two-stage enhancement framework is proposed in this paper. In the first stage, a lightweight image super-resolution (SR) sub-network is built by incorporating the external guidance obtained by the detection backbone, so that the potential discriminant features can be well preserved. Moreover, to alleviate the hardship of directly learning a nonlinear mapping from the LR space to the high-resolution (HR) space, an auxiliary module which maps the SR results back to the degraded LR images provides additional constraint. In the second stage, the multi-scale features produced by the detection heads are further enhanced by the lightweight feature adaptation modules, which aim to further bridge the gap between the SR result and the corresponding HR image. During training, the detector is kept frozen in our framework, leading to a flexible plug-and-play mechanism. Experiments demonstrate that our approach achieves better performance on LR images than many state-of-the-art methods. To facilitate further study, our source code will be available at: https://github.com/Zijian-Yuan/TSE-YOLO.