论文标题

SSP置端:直接类别级对象姿势估计的对称性 - 感知形状的先验变形

SSP-Pose: Symmetry-Aware Shape Prior Deformation for Direct Category-Level Object Pose Estimation

论文作者

Zhang, Ruida, Di, Yan, Manhardt, Fabian, Tombari, Federico, Ji, Xiangyang

论文摘要

类别级别的姿势估计是由于类内形状变化而导致的一个具有挑战性的问题。最近的方法变形了预计的形状先验,将观察到的点云映射到归一化对象坐标空间中,然后通过后处理(即Umeyama的算法)检索姿势。这种两阶段策略的缺点在于两个方面:1)中间结果的替代监督无法直接指导姿势的学习,从而导致后期处理后造成姿势错误。 2)推理速度受后处理步骤的限制。在本文中,为了处理这些缺点,我们为类别级别的姿势估计提出了一个端到端的可训练网络SSP置序,该网络将Shape Priors整合到直接的姿势回归网络中。 SSP置式堆栈在共享特征提取器上的四个单独分支,其中两个分支旨在变形和匹配先前的模型与观察到的实例,并且其他两个分支被用于直接回归完全9度的自由姿势,并分别执行对称性重建和点智慧的内部掩码掩码预测。然后,自然利用一致性损失项,以使不同分支的输出保持一致并促进性能。在推断期间,仅需要直接姿势回归分支。通过这种方式,SSP置端不仅学习类别级别的姿势敏感特征以提高性能,而且还可以保持实时推理速度。此外,我们利用每个类别的对称信息来指导形状事先变形,并提出一种新颖的对称性感知损失来减轻匹配的歧义。在公共数据集上进行的广泛实验表明,与实时推理速度约25Hz的竞争对手相比,SSP置孔可以产生卓越的性能。

Category-level pose estimation is a challenging problem due to intra-class shape variations. Recent methods deform pre-computed shape priors to map the observed point cloud into the normalized object coordinate space and then retrieve the pose via post-processing, i.e., Umeyama's Algorithm. The shortcomings of this two-stage strategy lie in two aspects: 1) The surrogate supervision on the intermediate results can not directly guide the learning of pose, resulting in large pose error after post-processing. 2) The inference speed is limited by the post-processing step. In this paper, to handle these shortcomings, we propose an end-to-end trainable network SSP-Pose for category-level pose estimation, which integrates shape priors into a direct pose regression network. SSP-Pose stacks four individual branches on a shared feature extractor, where two branches are designed to deform and match the prior model with the observed instance, and the other two branches are applied for directly regressing the totally 9 degrees-of-freedom pose and performing symmetry reconstruction and point-wise inlier mask prediction respectively. Consistency loss terms are then naturally exploited to align the outputs of different branches and promote the performance. During inference, only the direct pose regression branch is needed. In this manner, SSP-Pose not only learns category-level pose-sensitive characteristics to boost performance but also keeps a real-time inference speed. Moreover, we utilize the symmetry information of each category to guide the shape prior deformation, and propose a novel symmetry-aware loss to mitigate the matching ambiguity. Extensive experiments on public datasets demonstrate that SSP-Pose produces superior performance compared with competitors with a real-time inference speed at about 25Hz.

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