Baggage Image Retrieval with Attention-Based Network for Security Checks

Baggage image search is the task of finding the same baggage across several cameras, which can improve the efficiency of security check. Since existing state-of-the-art image retrieval requires a significant amount of training data, we aim to investigate the few-shot situation, utilizing only a few samples for each baggage. In this paper, the framework we introduced is called AttentionNet, exploring the weak region-wise annotations as attention clues to improve the retrieval performance. Specifically, we integrate the semantic and recognition tasks using shared convolutional neural networks by multi-task learning. Semantic attention mechanism is used to explicitly re-weight the feature map for emphasizing the foreground. To prevent overfitting in few-shot training, we adopt a variant of the triplet loss to perform deep metric learning with an online hard triplet mining strategy. Once trained, AttentionNet identifies a probe image by computing its embedding’s cosine distance with images in the gallery. Experiments show that our method achieves state-of-the-art accuracy in image search. For instance, we obtain 82.9% Rank-1 score on the MVB dataset, dramatically outperforming the currently existing methods.