Dual Structural Knowledge Interaction for Domain Adaptation

Domain adaptation aims to transfer knowledge from a label-rich source domain to an unlabeled target domain. A common strategy is to assign pseudo-labels to unlabeled target samples for performing representation learning. However, most existing methods only apply the source-guided classifier to generate the source-biased pseudo-labels for self-training, leading to biased target representations. Moreover, the generated pseudo-labels ignore the manifold assumption that neighboring samples are likely to have the same labels. To address the above problem, we formulate a novel structural knowledge to assign target-oriented and manifold-guided pseudo-labels for unlabeled target samples. The structural knowledge consists of cluster-based knowledge and locality-based knowledge. The cluster-based knowledge denotes the label consistency between the target samples and the non-parametric target cluster centers, making the pseudo-labels target-oriented. The locality-based knowledge constrains the target sample and its neighbors to satisfy the manifold assumption. As the neighbors contain the source and target samples, the source and target locality-based knowledge are utilized to boost the descriptions. With the structural knowledge, we propose a novel Dual Structural Knowledge Interaction (DSKI) framework for domain adaptation. For generating aligned and discriminative features, knowledge consistency constraint and instance mutual constraint are proposed in DSKI. Evaluations on three benchmarks demonstrate the effectiveness of the Dual Structural Knowledge Interaction, e.g., 74.9%, 87.7%, and 90.8% for Office-Home, VisDa-2017, and Office-31, respectively.