Deep Hashing with Active Pairwise Supervision

n this paper, we propose a Deep Hashing method with Active Pairwise Supervision(DH-APS). Conventional methods with passive pairwise supervision obtain labeled data for training and require large amount of annotations to reach their full potential, which are not feasible in realistic retrieval tasks. On the contrary, we actively select a small quantity of informative samples for annotation to provide effective pairwise supervision so that discriminative hash codes can be obtained with limited annotation budget. Specifically, we generalize the structural risk minimization principle and obtain three criteria for the pairwise supervision acquisition: uncertainty, representativeness and diversity. Accordingly, samples involved in the following training pairs should be labeled: pairs with most uncertain similarity, pairs that minimize the discrepancy between labeled and unlabeled data, and pairs which are most different from the annotated data, so that the discriminality and generalization ability of the learned hash codes are significantly strengthened. Moreover, our DH-APS can also be employed as a plug-and-play module for semi-supervised hashing methods to further enhance the performance. Experiments demonstrate that the presented DH-APS achieves the accuracy of supervised hashing methods with only $30\%$ labeled training samples and improves the semi-supervised binary codes by a sizable margin.