PAIR: Perception Aided Image Restoration for Natural Driving Conditions

Pranjay Shyam, HyunJin Yoo; Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision (WACV), 2024, pp. 7459-7470

We present a two-stage mechanism for generic image restoration in natural driving conditions, where multiple non-linear degradations simultaneously impact perception for humans and driving assistance systems. Our approach overcomes the limitations of utilizing a single neural network that incurs excessive computational overhead and yields sub-optimal recovery. The proposed first stage comprises computationally inexpensive image processing operations applied at a patch level using a lightweight convolutional neural network (CNN) that determines their intensity of operation. This patch size is guided by the receptive field of the CNN, allowing for dynamic restoration of non-linear and non-homogeneous degradation profiles. The second stage leverages a lightweight end-to-end neural network functioning as an inpainting network. It identifies inadequately restored regions and leverages global semantic and structural information to fill the affected areas. This approach enhances the restoration process by considering the entire image and addresses the remainder of localized deficiencies. In addition, we integrate dense perception tasks such as semantic and depth estimation during the optimization cycle to ensure restored images that are perceptually pleasing and conducive for downstream perception tasks. Since datasets covering diverse degradation scenarios for high- and low-level perception tasks are lacking, we utilize a synthetic data augmentation technique to generate non-homogeneous non-linear degradation profiles. Experiments on images captured in adverse weather conditions demonstrate the efficacy of our approach, yielding higher perceptual quality in restored images and improved performance in downstream perception tasks under adverse driving conditions. Importantly, our method offers computational efficiency compared to end-to-end image restoration algorithms, making it suitable for real-time applications.