The design of mobile navigation systems adapting to limited resources will be an important future challenge. Since typically several different means of transportation have to be combined in order to reach a destination, the user interface of such a system has to adapt to the user's changing situation. This applies especially to the alternating use of different technologies to detect the user's position, which should be as seamless as possible. This article presents a hybrid navigation system that relies on different technologies to determine the user's location and that adapts the presentation of route directions to the limited technical resources of the output device and the limited cognitive resources of the user.

In this work we investigate building indoor location based applications for a mobile augmented reality system. We believe that augmented reality is a natural interface to visualize spacial information such as position or direction of locations and objects for location based applications that process and present information based on the user's position in the real world. To enable such applications we construct an indoor tracking system that covers a substantial part of a building. It is based on visual tracking of fiducial markers enhanced with an inertial sensor for fast rotational updates. To scale such a system to a whole building we introduce a space partitioning scheme to reuse fiducial markers throughout the environment. Finally we demonstrate two location based applications built upon this facility, an indoor navigation aid and a library search application.

Augmented Reality (AR) provides a natural interface to the "calm" pervasive technology anticipated in large-scale Ubiquitous Computing environments. However, the range of classic AR applications has been limited by the scope, range and cost of sensors used for tracking. Hybrid tracking approaches can go some way to extending this range. We propose an approach, called Ubiquitous Tracking, in which data from widespread and diverse heterogeneous tracking sensors is automatically and dynamically fused, and then transparently provided to applications. A formal model represents spatial relationships between objects as a graph attributed with quality-of-service parameters. This paper presents a software implementation, in which a dynamic data flow network of distributed software components is thereby constructed in response to queries and optimisation criteria specified by applications. This implementation is demonstrated using a small laboratory example, and larger setups modelled in a simulation environment.

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, who 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 actively managed so as to maximize the relevance and minimize the confusion of the 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 context-dependent operations, many of which are related to the objects in viewFthe augmented world is the user interface. We present three UI design techniques that are intended to make this interface as obvious and clear to the user as possible: information filtering, UI component design, and view management. Information filtering helps select the most relevant information to present to the user. UI component design determines the format in which this 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-stabilized ones that would need to be exactly registered with

We present a mobile augmented reality (AR) system to guide a user through an unfamiliar building to a destination room. The system presents a world-registered wire frame model of the building labeled with directional information in a see-through heads-up display, and a three-dimensional world-in-miniature (WIM) map on a wrist-worn pad that also acts as an input device. Tracking is done using a combination of wall-mounted ARToolkit markers observed by a head-mounted camera, and an inertial tracker. To allow coverage of arbitrarily large areas with a limited set of markers, a structured marker re-use scheme based on graph coloring has been developed.

All augmented reality (AR) systems must deal with registration errors. While most AR systems attempt to minimize registration errors through careful calibration, registration errors can never be completely eliminated in any realistic system. In this paper, we describe a robust and efficient statistical method for estimating registration errors. Our method generates probabilistic error estimates for points in the world, in either 3D world coordinates or 2D screen coordinates. We present a number of examples illustrating how registration error estimates can be used in AR interfaces, and describe a method for estimating registration errors of objects based on the expansion and contraction of their 2D convex hulls.

We present a novel, inexpensive, coarse tracking system that determines a person’s approximate 2D location and 1D head orientation in an indoor environment. While this coarse tracking cannot support precise registration of overlaid material, it can be used to drive user interfaces that can adapt to the quality of tracking available. Our approach uses a set of strong infrared beacons, each of which broadcasts a unique ID. The beacons are deployed in the environment such that their zones of influence strategically overlap, partitioning the area of coverage into a set of uniquely identifiable fragments. We use a compound, omnidirectional infrared receiver, composed of a set of individual, directional infrared receivers, to infer 2D position (parallel to the ground plane) and 1D orientation (azimuth), employing a Kalman-filter–based architecture for smoothing and data integration with other tracking systems available. To test our ideas, we have applied them to a prototype head tracker, and present results from our tests. 1.

Any significant real-world application of mobile augmented reality will require a large model of location-bound data. While it may appear that a natural approach is to develop application-specific data formats and management strategies, we have found that such an approach actually prevents reuse of the data and ultimately produces additional complexity in developing the application. In contrast we describe a three-tier architecture to manage a common data model for a set of applications. It is inspired by current Internet application frameworks and consists of a central storage layer using a common data model, a transformation layer responsible for filtering and adapting the data to the requirements of a particular applications on request, and finally of the applications itself. We demonstrate our architecture in a scenario consisting of two multi-user capable mobile AR applications for collaborative navigation and annotation in a city environment.

In this dissertation, we present typical components of, useful services associated with, and user interactions possible with mobile augmented reality systems, based on a comprehensive series of hardware and software infrastructures and application prototypes we developed. We define a practical taxonomy of user interface components for such systems and establish methodology for adaptive mobile augmented reality interfaces that dynamically rearrange themselves in response to changes in user context. The research contributions to the state-of-the-art in augmented reality begin with the author’s participation in the design of the ”Columbia Touring Machine ” in 1997, the first example of an outdoor mobile augmented reality system, and his lead in developing later prototypes. We develop a series of hardware and software infrastructures for prototyping mobile augmented reality applications that allow multiple users to participate in collaborative tasks taking place indoors and outdoors. We present exploratory user interfaces for many different applications and user scenarios, including the Situated Documentaries application framework for experiencing spatially distributed hypermedia presentations. Based on these explorations, we develop

Research on mobile augmented reality (AR) so far concentrated on building and deploying prototypes and investigating technical and user interface aspects. To create plausible application scenarios other concerns also need to be addressed. In particular, the size of the physical world made accessible by mobile AR raises new challenges in terms of scalability: the system will among others need a very large 3D world model, display this model efficiently without visual clutter or graphics overload, should operate in networked mode with arbitrary collaborators, provide tracking anywhere etc. In this paper we address some of these scalability issues, namely data management for very large geographic 3D models, and efficient techniques for collaborative outdoor user interfaces. As an application scenario, we use a tourist group guide application operating in the city of Vienna.