Jason Wither

Mobile Augmented Reality: Indirect augmented reality

Developing augmented reality (AR) applications for mobile devices and outdoor environments has historically required a number of technical trade-offs related to tracking. One approach is to rely on computer vision which provides very accurate tracking, but can be brittle, and limits the generality of the application. Another approach is to rely on sensor-based tracking which enables widespread use, but at the cost of generally poor tracking performance. In this paper we present and evaluate a new approach, which we call Indirect AR, that enables perfect alignment of virtual content in a much greater number of application scenarios. To achieve this improved performance we replace the live camera view used in video see through AR with a previously captured panoramic image. By doing this we improve the perceived quality of the tracking while still maintaining a similar overall experience. There are some limitations of this technique, however, related to the use of panoramas. We evaluate these boundaries conditions on both a performance and experiential basis through two user studies. The result of these studies indicates that users preferred Indirect AR over traditional AR in most conditions, and when conditions do degrade to the point the experience changes, Indirect AR can still be a very useful tool in many outdoor application scenarios.

The Westwood Experience: Connecting story to locations via Mixed Reality

The Westwood Experience is a location-based narrative using Mixed Reality effects to connect participants to unique and evocative real locations, bridging the gap between the real and story worlds. This paper describes the experience and a detailed evaluation of it. The experience itself centers around a narrative told by the “mayor” of Westwood. He tells a love story from his youth when he first came to Westwood, and intermixes the story with historical information. Most of this story is told on a mobile computer, using Mixed Reality and video for illustration. We evaluate the experience both quantitatively and qualitatively to find lessons learned about the experience itself and general guidelines for this type of experience. The analysis and guidelines from our evaluation are grouped into three categories: narration in mobile environments, social dynamics, and Mixed Reality effects.

Mobile Augmented Reality at the Hollywood Walk of Fame

This work introduces techniques to facilitate large-scale Augmented Reality (AR) experiences in unprepared outdoor environments. We develop a shape-based object detection framework that works with limited texture and can robustly handle extreme illumination and occlusion issues. The contribution of this work is a purely geometric approach for detecting marker-like objects under difficult and realistic outdoor conditions. We demonstrate these techniques for mobile AR experiences by detecting and tracking star-shaped pentagrams embedded in the Hollywood Walk of Fame at 30Hz on a Nokia N900 phone.

Comparing spatial understanding between touch-based and AR-style interaction

There are currently two primary ways of viewing location specific information in-situ on hand-held mobile device screens: using a see-through augmented reality interface and using a touch-based interface with panoramas. The two approaches use fundamentally different interaction metaphors: an AR-style of interacting where the user holds up the device and physically moves it to change views of the world, and a touch-based technique where panorama navigation is independent of the physical world. We have investigated how this difference in interaction technique impacts a users spatial understanding of the mixed reality world. Our study found that AR-style interaction provided better spatial understanding overall, while touch-based interaction changed the experience to have more similar characteristics to interaction in a separate virtual environment.

Tagger: Bringing Real World Graffiti Social Interaction to Virtual San Francisco

We present Tagger, a game designed to reproduce the social interactions of graffiti lifestyle in a geo-accurate virtual mirror world. Players interact by placing user-generated artwork on photo realistic panoramas of the city of San Francisco. Tagger is unique in the scope and accuracy to which it reproduces an entire city in a virtual environment. We present our design, implementation experience, and results from two user studies. We show that real world graffiti social interactions occurred in our mirror world despite limitations with our first generation game play rules that inadvertently disincentivized this behavior. We also show that setting the game in a mirror of the real world contributes to players enjoyment and choice of strategies. We expect Tagger will continue to serve as a powerful research platform as we investigate broader questions around how the virtual mirror world, perhaps combined with augmented reality technology, can extend social interactions beyond what is possible in todays physical world of graffiti.