Deep multiscale divergence hashing for image retrieval

Abstract. Image retrieval based on deep learning of hash has made great progress. The hash method increases retrieval speed greatly while saving storage space. However, some problems exist, such as the distinctiveness of image feature still needs to be improved and some image features are still redundant. We propose a new deep learning to hash method, namely, deep multiscale divergence hashing, which provides a high diversity and compact image feature for image retrieval. The discriminative features from deep neural networks are identified by the importance criterion in network pruning techniques and the feature redundancy is reduced. Then, the selected features across different layers are fused in a certain proportion to increase the diversity of features for image retrieval. We also present a hybrid loss function in hash space, which consists of the weighted pairwise cross-entropy loss function and the KL-divergence. It tends to minimize the hamming distance between similar images and maximize the hamming distance between different images, which helps improve the accuracy. Massive experimental results show that our method achieves better feature distinguishability and more advanced image retrieval accuracy, and surpasses HashNet by 11.46%, 7.58%, and 13.86% on MS COCO, NUS-WIDE, and CIFAR-10 datasets, respectively.