  Current 3D single object tracking methods are typically based on VoteNet, a
3D region proposal network. Despite the success, using a single seed point
feature as the cue for offset learning in VoteNet prevents high-quality 3D
proposals from being generated. Moreover, seed points with different importance
are treated equally in the voting process, aggravating this defect. To address
these issues, we propose a novel global-local transformer voting scheme to
provide more informative cues and guide the model pay more attention on
potential seed points, promoting the generation of high-quality 3D proposals.
Technically, a global-local transformer (GLT) module is employed to integrate
object- and patch-aware prior into seed point features to effectively form
strong feature representation for geometric positions of the seed points, thus
providing more robust and accurate cues for offset learning. Subsequently, a
simple yet effective training strategy is designed to train the GLT module. We
develop an importance prediction branch to learn the potential importance of
the seed points and treat the output weights vector as a training constraint
term. By incorporating the above components together, we exhibit a superior
tracking method GLT-T. Extensive experiments on challenging KITTI and NuScenes
benchmarks demonstrate that GLT-T achieves state-of-the-art performance in the
3D single object tracking task. Besides, further ablation studies show the
advantages of the proposed global-local transformer voting scheme over the
original VoteNet. Code and models will be available at
https://github.com/haooozi/GLT-T.
