In augmented reality (AR), virtual objects can drift away from their original intended locations, significantly impairing a user’s experience. Traditionally, a virtual object’s drift is approximated by the device localization drift, which is measured using specialized hardware such as 3D scanners or laser-based positioning systems. However, with AR rapidly becoming more popular, there is a need for a lightweight, software-based approach to evaluate the drift of virtual objects. This software should be easy for researchers and developers to use, without requiring specialized hardware or extensive environment setup.Towards this, this paper presents RealityCheck, an opensource AR evaluation tool that reports the drift of AR virtual objects in the world coordinate system, requiring only paper printouts and minimal modifications to the AR app. RealityCheck is designed to measure the drift of a virtual object across time of a single user, as well as the positioning differences of the same virtual objects as seen by multiple users. Our prototype is implemented on an Android smartphone running the ARCore platform, and evaluated in indoor and outdoor scenarios under a variety of user mobility patterns with traces of different lengths. We compared the results of RealityCheck with the ground truth position of the virtual object, and showed that RealityCheck matches the ground truth within 1.5 cm on average.

Multi-user augmented reality (AR), where multiple co-located users view a common set of virtual objects, is becoming increasingly popular. For example, Google Just a Line allows multiple users to draw virtual graffiti in the same physical space. Multi-user AR requires network communications in order to coordinate the positions of the virtual objects on each user's display, yet there is currently little understanding of how such apps communicate. In this work, we address this key gap in knowledge by showing that the communicated data directly impacts the latency and positioning of the virtual objects rendered on the users' displays. We develop solutions to these problems that we find along three facets: (1) efficient communication strategies that trade off communication latency for spatial consistency of the virtual objects; (2) a new metric that enables mobile AR devices to update their virtual objects as they move around and observe more of the scene; and (3) a tool to automatically quantify how much the virtual objects' positions inadvertently change in time and space. Our evaluation is performed on Android smartphones running open-source AR. The results show that our system, SPAR, can decrease the latency by up to 55%, while decreasing the spatial inconsistency by up to 60%, compared to baseline methods.

Augmented reality is an emerging application on mobile devices. However, there is a lack of understanding of the communication requirements and challenges of multi-user AR scenarios. In this position paper, we propose several important research issues that need to be addressed for low-latency, accurate shared AR experiences: (a) Systems tradeoffs of AR communication architectures used today in mobile AR platforms; (b) Understanding AR communication patterns and adapting the AR application layer to dynamically changing network conditions; and (c) Tools and methodologies to evaluate AR quality of experience in real time on mobile devices. We present preliminary measurements of off-the-shelf mobile AR platforms as well as results from our AR system, ShareAR, illustrating performance tradeoffs and indicating promising new research directions.