We investigate mobile phone pointing in Spatial Augmented Reality (SAR), where digital content is mapped onto the surfaces of a real physical environment. Three pointing techniques are compared: raycast, viewport, and direct. A first experiment examines these techniques in a realistic five-projector SAR environment with representative targets distributed across different surfaces. Participants were permitted free movement, so variations in target occlusion and target view angle occurred naturally. A second experiment validates and further generalizes findings by strictly controlling target occlusion and view angle in a simulated SAR pointing task using an AR HMD. Overall, results show raycast is fastest for non-occluded targets, direct is most accurate, and fastest for occluded targets in close proximity, and viewport falls in between. Using the experiment data, we formulate and evaluate a new Fitts’ model combining two spatial configurations in a SAR pointing task to capture key characteristics, initial target occlusion, target view angle, and user movement. Analysis shows it is a better predictor than previous models.

我们研究了空间增强现实（SAR）中的移动电话指向，其中数字内容被映射到真实物理环境的表面上。比较了三种指向技术：光线投射，视口和直接。第一个实验在现实的五投影仪SAR环境中检查了这些技术，其代表性目标分布在不同的表面上。允许参与者自由移动，因此自然会发生目标遮挡和目标视角的变化。第二个实验通过使用AR HMD在模拟的SAR指向任务中严格控制目标遮挡和视角，从而验证并进一步概括了发现。总体而言，结果表明，对于非遮挡目标，光线投射最快，对于最接近的遮挡目标，直接光线投射最准确，并且视口介于两者之间。使用实验数据，我们制定并评估了一个新的Fitts模型，该模型在SAR指向任务中结合了两种空间配置，以捕获关键特征，初始目标遮挡，目标视角和用户移动。分析表明，它比以前的模型更好。