Towards Making Unsupervised Graph Hashing Robust

Unsupervised hashing without supervision easily deteriorates in the case of grossly corrupted data. Motivated by robust optimization, this paper proposes a dual-graph regularized robust hashing (DGRH) based on both manifold smoothness and robust estimators in a more intuitive manner. Orthogonal to existing robust hashing methods, DGRH directly removes the outliers of datasets with M-estimator to exert robustness. In specific, it intends to recover low-rank representation from corrupted data via $l_1$ loss while preserving neighborhood relationships among samples with dual-graph regularization. Although DGRH seems a simple extension of robust PCA on graphs with hashing trick, it is easy to implement yet effective. Theory analysis is provided to support our claim. Experiments of image retrieval on three popular benchmark datasets show the efficacy of DGRH as compared to several well-behaved representative counterparts.