PIT: A Plug-and-Play Image Translator for Making Off-the-Shelf Models Adapt to Corruptions

Visual recognition models pretrained on clean images usually do not perform well in the presence of image corruptions, such as blurring or noise, which limits their applicability in real-world scenarios. To solve this problem, existing approaches usually design complex data augmentations to train a robust model from scratch or adapt a pretrained model to corrupted scenarios. These approaches ignore the existence of the large number of deployed models in our community, causing extensive computation and storage costs for making deployed models adapted. Based on this consideration, this paper focuses on solving a practical problem of making many clean-image-pretrained models adapt to unlabeled corrupted images through one training procedure. To this end, we aim to learn a Plug-and-play Image Translator (PIT) that can be directly combined with recognition models after training. Existing approaches, such as vanilla image translation and restoration, are not proper for solving this problem, as they are mostly based on supervised training and are not recognition-oriented. To address this issue, we propose a recognition-oriented unsupervised image translation framework to make PIT produce images with indistinguishable recognition predictions from the clean ones. We verify the effectiveness of PIT on several recognition tasks and show that PIT boosts the performance of clean-image-pretrained models significantly in the presence of image corruptions.