Zero-shot discrete hashing with adaptive class correlation for cross-modal retrieval

Abstract

Zero-shot retrieval aims to transfer knowledge from seen classes to unseen classes by embedding semantic information on class attributes, thus solving the unseen class retrieval problem. However, existing works have focused mainly on unimodal zero-shot retrieval tasks. In this paper, we introduce an efficient method, termed zero-shot discrete hashing with adaptive class correlation (ZSDH-ACC), to speed up cross-modal retrieval. Specifically, this proposed method combines label information with class attribute information to construct a semantic enhancement embedding, in which the problem of class attribute correspondence of multilabel instances can be solved. Furthermore, we learn semantic enhancement embedding to merge more semantic information for feature representation, and its goal is to learn more discriminative hash codes and hash functions. In addition, our proposed method adaptively learns the correlation between class attributes and then embeds more class attribute information into hash codes. Finally, pairwise similarity is used to constrain the learning of hash codes, and thus more discriminative hash codes can be generated. Extensive experimental results on four benchmark multimodal datasets demonstrate that the proposed ZSDH-ACC method can achieve encouraging performance in cross-modal retrieval tasks. The source code of this paper can be obtained from https://github.com/szq0816/ZSDH_ACC.