Assisting Spatial Referencing for Collaborative Augmented Reality

Spatial referencing denotes the act of referring to a location or an object in space. Since it is often essential in different collaborative activities, good support for spatial referencing could lead to exceptional collaborative experience and performance. Augmented Reality (AR) aims to enhance daily activities and tasks in the real world, including various collaborations and social interactions. Good support for accurate and rapid spatial referencing in collaborative AR often requires detailed environment 3D information, which can be critical for the system to acquire as constrained by current technology. This dissertation seeks to address the issues related to spatial referencing in collaborative AR through 3D user interface design and different experiments. Specifically, we start with investigating the impact of poor spatial referencing on close-range, co-located AR collaborations. Next, we propose and evaluate different pointing ray techniques for object reference at a distance without knowledge from the physical environment. We further introduce marking techniques aiming to accurately acquire the position of an arbitrary point in 3D space that can be used for spatial referencing. Last, we provide a systematic assessment of an AR collaborative application that supports efficient spatial referencing in remote learning to demonstrate its benefit. Overall, the dissertation provides empirical evidence of spatial referencing challenges and benefits to collaborative AR and solutions to support adequate spatial referencing when model information from the environment is missing.