IEEE Trans Vis Comput Graph. 2022 Nov;28(11):3705-3714. doi: 10.1109/TVCG.2022.3203109. Epub 2022 Oct 21.
Avatar-mediated symmetric Augmented Reality (AR) telepresence has emerged with the ability to empower users located in different remote spaces to interact with each other in 3D through avatars. However, different spaces have heterogeneous structures and features, which bring difficulties in synchronizing avatar motions with real user motions and adapting avatar motions to local scenes. To overcome these issues, existing methods generate mutual movable spaces or retarget the placement of avatars. However, these methods limit the telepresence experience in a small sub-area space, fix the positions of users and avatars, or adjust the beginning/ending positions of avatars without presenting smooth transitions. Moreover, the delay between the avatar retargeting and users' real transitions can break the semantic synchronization between users' verbal conversation and perceived avatar motion. In this paper, we first examine the impact of the aforementioned transition delay and explore the preferred transition style with the existence of such delay through user studies. With the results showing a significant negative effect of avatar transition delay and providing the design choice of the transition style, we propose a Predict-and-Drive controller to diminish the delay and present the smooth transition of the telepresence avatar. We also introduce a grouping component as an upgrade to immediately calculate a coarse virtual target once the user initiates a transition, which could further eliminate the avatar transition delay. Once having the coarse virtual target or an exactly predicted target, we find the corresponding target for the avatar according to the pre-constructed mapping of objects of interest between two spaces. The avatar control component maintains an artificial potential field of the space and drives the avatar towards the target while respecting the obstacles in the physical environment. We further conduct ablation studies to evaluate the effectiveness of our proposed components.
化身介导的对称增强现实 (AR) 远程临场感具有使位于不同远程空间的用户能够通过化身在 3D 中相互交互的能力。然而，不同的空间具有异构的结构和特征，这给同步化身运动与真实用户运动以及适应化身运动到本地场景带来了困难。为了克服这些问题，现有方法生成可相互移动的空间或重新定位化身的位置。然而，这些方法限制了远程临场感体验在小的子区域空间中，固定用户和化身的位置，或者调整化身的起始/结束位置，而没有呈现平滑的过渡。此外，化身重新定位和用户真实过渡之间的延迟可能会破坏用户口头对话和感知化身运动之间的语义同步。在本文中，我们首先检查了上述过渡延迟的影响，并通过用户研究探索了存在这种延迟时的首选过渡风格。结果表明，化身过渡延迟具有显著的负面影响，并提供了过渡风格的设计选择，我们提出了一种预测和驱动控制器来减少延迟并呈现远程临场感化身的平滑过渡。我们还引入了分组组件作为升级，一旦用户发起过渡，即可立即计算粗略的虚拟目标，从而进一步消除化身过渡延迟。一旦有了粗略的虚拟目标或精确预测的目标，我们根据两个空间之间感兴趣的物体的预构建映射找到相应的化身目标。化身控制组件维护空间的人工势能场，并在尊重物理环境中的障碍物的情况下驱动化身朝向目标。我们进一步进行了消融研究来评估我们提出的组件的有效性。
