TransferAttn: Transferable-guided Attention Is All You Need for Video Domain Adaptation

Unsupervised domain adaptation (UDA) in videos is a challenging task that remains not well explored compared to image-based UDA techniques. Although vision transformers (ViT) achieve state-of-the-art performance in many computer vision tasks, their use in video domain adaptation has still been little explored. Our key idea is to use the transformer layers as a feature encoder and incorporate spatial and temporal transferability relationships into the attention mechanism. A Transferable-guided Attention (TransferAttn) framework is then developed to exploit the capacity of the transformer to adapt cross-domain knowledge from different backbones. To improve the transferability of ViT, we introduce a novel and effective module named Domain Transferable-guided Attention Block~(DTAB). DTAB compels ViT to focus on the spatio-temporal transferability relationship among video frames by changing the self-attention mechanism to a transferability attention mechanism. Extensive experiments on UCF-HMDB, Kinetics-Gameplay, and Kinetics-NEC Drone datasets with different backbones, like ResNet101, I3D, and STAM, verify the effectiveness of TransferAttn compared with state-of-the-art approaches. Also, we demonstrate that DTAB yields performance gains when applied to other state-of-the-art transformer-based UDA methods from both video and image domains. The code will be made freely available.