Florian Ledermann

Towards massively multi-user augmented reality on handheld devices

Augmented Reality (AR) can naturally complement mobile computing on wearable devices by providing an intuitive interface to a three-dimensional information space embedded within physical reality. Unfortunately, current wearable AR systems are relatively complex, expensive, fragile and heavy, rendering them unfit for large-scale deployment involving untrained users outside constrained laboratory environments. Consequently, the scale of collaborative multi-user experiments have not yet exceeded a handful of participants. In this paper, we present a system architecture for interactive, infrastructure-independent multi-user AR applications running on off-the-shelf handheld devices. We implemented a four-user interactive game installation as an evaluation setup to encourage playful engagement of participants in a cooperative task. Over the course of five weeks, more than five thousand visitors from a wide range of professional and socio-demographic backgrounds interacted with our system at four different locations.

APRIL: a high-level framework for creating augmented reality presentations

While augmented reality (AR) technology is steadily maturing, application development is still lacking advanced authoring tools - even the simple presentation of information, which should not require any programming, is not systematically addressed by development tools. Moreover, there is also a severe lack of agreed techniques or best practices for the structuring of AR content. In this paper we present APRIL, the Augmented Presentation and Interaction Language, an authoring platform for AR presentations which provides concepts and techniques that are independent of specific applications or target hardware platforms, and should be suitable to raise the level of abstraction on which AR content creators can operate.

Managing Complex Augmented Reality Models

Mobile augmented reality requires georeferenced data to present world-registered overlays. To cover a wide area and all artifacts and activities, a database containing this information must be created, stored, maintained, delivered, and finally used by the client application. We present a data model and a family of techniques to address these needs.

Two-handed direct interaction with ARTootKit

A mobile augmented reality system for 3D interaction requires an easy to use, interactive input device. In our work on the Studierstube project, we had long-term experience with two-handed direct manipulation interfaces based on tracked props. However, for a mobile setup, props are no longer appropriate as they permanently occupy the users hands and prevent the user from performing everyday tasks such as opening doors. Instead, we resorted to the common tool which is very intuitive to use and can be applied for nearly all interactions: our hands. A big advantage of hand based interaction is the intuitive use of gestures such as pointing, grabbing or stretching.