User interface management techniques for collaborative mobile augmented reality

Mobile augmented reality systems (MARS) have the potential to revolutionize the way in which information is provided to users. Virtual information can be directly integrated with the real world surrounding the mobile user, wh o can interact with it to display related information, to pose and resolve queries, and to collaborate with other users. However, we believe that the benefits of MARS will only be achieved if the user interface (UI) is active ly managed so as to maximize the relevance and minimize the confusion of th e virtual material relative to the real world. This article addresses some of the steps involved in this process, focusing on the design and layout of the mobile user's overlaid virtual environment. The augmented view of the user's surroundings presents an interface to cont ext-dependent operations, many of which are related to the objects in view- the augmented world is the user interface. We present three UI design techn iques that are intended to make this interface as obvious and clear to the user as possible: information filtering, UI component design, and view mana gement. Information filtering helps select the most relevant information to present to the user. UI component design determines the format in which th is information should be conveyed, based on the available display resources and tracking accuracy. For example, the absence of high accuracy position tracking would favor body- or screen-stabilized components over world-stabi lized ones that would need to be exactly registered with the physical objec ts to which they refer. View management attempts to ensure that the virtual objects that are displayed visually are arranged appropriately with regard to their projections on the view plane. For example, the relationships amo ng objects should be as unambiguous as possible, and physical or virtual ob jects should not obstruct the user's view of more important physical or vir tual objects in the scene. We illustrate these interface design techniques using our prototype collaborative, cross-site MARS environment, which is co mposed of mobile and non-mobile augmented reality and virtual reality syste ms. (C) 2001 Published by Elsevier Science Ltd.