Bi-Direction Label-Guided Semantic Enhancement for Cross-Modal Hashing

Supervised cross-modal hashing has gained significant attention due to its efficiency in reducing storage and computation costs while maintaining rich semantic information. Despite substantial progress in generating compact binary codes, two key challenges remain: (1) insufficient utilization of labels to mine and fuse multi-grained semantic information, and (2) unreliable cross-modal interaction, which does not fully leverage multi-grained semantics or accurately capture sample relationships. To address these limitations, we propose a novel method called Bi-direction Label-Guided Semantic Enhancement for cross-modal Hashing (BiLGSEH). To tackle the first challenge, we introduce a label-guided semantic fusion strategy that extracts and integrates multi-grained semantic features guided by multi-labels. For the second challenge, we propose a semantic-enhanced relation aggregation strategy that constructs and aggregates multi-modal relational information through bi-directional similarity. Additionally, we incorporate CLIP features to improve the alignment between multi-modal content and complex semantics. In summary, BiLGSEH generates discriminative hash codes by effectively aligning semantic distribution and relational structure across modalities. Extensive performance evaluations against 18 competitive methods demonstrate the superiority of our approach. The source code for our method is publicly available at: https://github.com/yileicc/BiLGSEH.