Self-Supervision & Meta-Learning for One-Shot Unsupervised Cross-Domain Detection

Deep detection models have largely demonstrated to be extremely powerful in controlled settings, but appear brittle and fail when applied off-the-shelf on unseen domains. All the adaptive approaches developed to amend this issue access a sizable amount of target samples at training time, a strategy not suitable when the target is unknown and its data are not available in advance. Consider for instance the task of monitoring image feeds from social media: as every image is uploaded by a different user it belongs to a different target domain that is impossible to foresee during training. Our work addresses this setting, presenting an object detection algorithm able to perform unsupervised adaptation across domains by using only one target sample, seen at test time. We introduce a multi-task architecture that one-shot adapts to any incoming sample by iteratively solving a self-supervised task on it. We further exploit meta-learning to simulate single-sample cross domain learning episodes and better align to the test condition. Moreover, a cross-task pseudo-labeling procedure allows to focus on the image foreground and enhances the adaptation process. A thorough benchmark analysis against the most recent cross-domain detection methods and a detailed ablation study show the advantage of our approach.