Proxy-Based Semi-Supervised Cross-Modal Hashing

Due to the difficulty in obtaining label information in practical applications, semi-supervised cross-modal retrieval has emerged. However, the existing semi-supervised cross-modal hashing retrieval methods mainly focus on exploring the structural relationships between data and generating high-quality discrete pseudo-labels while neglecting the relationships between data and categories, as well as the structural relationships between data and categories inherent in continuous pseudo-labels. Based on this, Proxy-based Semi-Supervised Cross-Modal Hashing (PSSCH) is proposed. Specifically, we propose a category proxy network to generate category center points in both feature and hash spaces. Additionally, we design an Adaptive Dual-Label Loss function, which applies different learning strategies to discrete ground truth labels and continuous pseudo-labels and adaptively increases the training weights of unlabeled data with more epochs. Experiments on the MIRFLICKR-25K, NUS-WIDE, and MS COCO datasets show that PSSCH achieves the highest mAP improvements of 3%, 1%, and 4%, respectively, demonstrating better results than the latest baseline methods.