Workspace Awareness in Collaborative AR using HMDs: A User Study Comparing Audio and Visual Notifications

For most professional tasks nowadays, it is necessary to work in teams. Such collaboration often requires the exchange of visual context-related information among the team members. For so-called shared workspace collaboration, awareness of other people's activities is of utmost importance. We have developed an augmented reality (AR) framework in order to support visual communication between a team of two people who are virtually co-located. We address these people as the remote user, who uses a laptop and the local user, who wears a head-mounted display (HMD) with an RGB camera. The remote user can support the local user in solving a spatial problem by providing instructions as virtual objects in the view of the local user. For placing virtual objects in the shared workspace, we use a state-of-the-art algorithm for localization and mapping without markers. In this paper, we report on a user study that explores on how automatic audio and visual notifications about the remote user's activities affect the collaboration. The results show that in our current implementation, visual notifications are preferred over audio or no notifications independent from the level of difficulty of the task.