视觉几何Transformer的Token选择指南
阅读原文· arxiv.org视觉几何Transformer是多视图3D重建的有力架构,但其全局注意力机制导致计算成本随输入序列长度二次增长。为此,研究提出一种通用的token选择策略,以限制每个查询交互的key/value token数量。该策略采用两阶段框架:首先在帧间通过多样性策略保留关键帧,然后在选定帧内基于注意力熵进行层级稀疏化以移除冗余token。实验表明,该方法在包含500张图像的场景中能加速超过85%,同时保持甚至提升基线性能,为该类架构提供了更优的速度-精度权衡。
Visual geometry transformers have become powerful architectures for multi-view 3D reconstruction, enabling joint prediction of multiple 3D attributes in a feed-forward manner. However, their computational cost grows quadratically with the input sequence length due to the global attention layers inside these models. This limits both their scalability and efficiency. In this work, we address this challenge with a simple yet general strategy: restricting the number of key/value tokens that each query interacts with during global attention. To achieve effective token selection, we introduce a two-stage framework. First, an inter-frame selection step operates at the frame level to identify frames that should be preserved. Second, an intra-frame selection step further discards more redundant tokens within the selected frames. Our analysis highlights the advantage of a diversity-based strategy for inter-frame selection, which ensures broad coverage of the scene. For intra-frame selection, we show that layer-aware sparsification is necessary, with the selection process guided by the entropy of the global attention pattern. Our approach offers a superior speed-accuracy trade-off compared to existing solutions. Extensive experiments show that it accelerates visual geometry transformers by over 85% for scenes with 500 images while maintaining, or even improving, baseline performance, which hints that how our token selection strategy can play a crucial role in future applications of visual geometry transformers. Our project website is available at https://zsh2000.github.io/good-token-hunting.github.io.