SiamUT: Siamese Unsymmetrical Transformer-like Tracking

Siamese networks have proven to be suitable for many computer vision tasks, including single object tracking. These trackers leverage the siamese structure to benefit from feature cross-correlation, which measures the similarity between a target template and the corresponding search region. However, the linear nature of the correlation operation leads to the loss of important semantic information and may result in suboptimal performance when faced with complex background interference or significant object deformations. In this paper, we introduce the Transformer structure, which has been successful in vision tasks, to enhance the siamese network’s performance in challenging conditions. By incorporating self-attention and cross-attention mechanisms, we modify the original Transformer into an asymmetrical version that can focus on different regions of the feature map. This transformer-like fusion network enables more efficient and effective fusion procedures. Additionally, we introduce a two-layer output structure with decoupling prediction heads, improved loss functions, and window penalty post-processing. This design enhances the performance of both the classification and the regression branches. Extensive experiments conducted on large public datasets such as LaSOT, GOT-10k, and TrackingNet demonstrate that our proposed SiamUT tracker achieves state-of-the-art precision performance on most benchmark datasets.