Selected Topics in Human-Computer Interaction

The theory component will provide an introductory overview of the following topics:

• Augmented reality (AR) versus virtual reality
• How does AR work?
• AR Display Technologies
• Head Tracking for Augmented Reality
• Augmented Reality Applications
• Interaction Techniques
• Mobile Augmented Reality
• Wearable Information Display
• ARQuake

We believe a wearable computer with an augmented reality (AR) [1] user interface allows for exciting new applications to be deployed in an outdoor environment. We refer to these systems as an Outdoor Wearable Augmented Reality Computer System (OWARCS). Like other researchers, we are taking the use of AR from the indoor setting and placing it in the outdoor environment. There have been a number of systems for outdoor augmented reality such as MARS [2], Touring machine [3], NRL BARS system [4], previous UniSA Tinmith navigation systems [5, 6], and UniSA ARQuake [7].

The operation of wearable computers in an outdoor setting is hampered by the lack of suitable input devices. Many traditional input devices such as mice and keyboards are not suitable for mobile work outdoors, as they require a level flat surface to operate. A second difficulty is the well-known registration problem. The field of virtual reality (VR) also suffers from the lack of proper input devices and sub-optimal tracking systems, and as a result, new input devices, interfaces, and trackers are continuing to be developed in an attempt to solve these problems. However, many of these devices require fixed infrastructure and are not useable in mobile outdoor environments. Two excellent papers by Azuma [1, 8] explain the problems of working outdoors, and the various technologies that are currently available.

The problem of registering virtual images with the user’s view of the physical world is a main focus of AR research. However, there is little previous work in the area of user interfaces for controlling AR systems in an outdoor setting. Two major issues for the development of these user interfaces are as follows: firstly, registration errors will make it difficult for a user to point at or select small details in the augmentation and secondly, pointing and selecting at a distance are known problems in virtual and augmented reality applications (compounded by the fact the user is outdoors with less than optimal six degree of freedom tracking of their head and hands).

Therefore, new user interaction techniques are required for an OWARCS, and to state the obvious, the input techniques the users are required to use will have a large impact on the usability of an OWARCS. A key element to the new user interactions is that the augmented reality systems have a varying number of coordinate systems (physical world, augmented world, body relative and screen relative) within which the user must work. In an outdoor application the registration errors of objects at a distance amplify the differences between the physical and augmented world coordinate systems.

1. Azuma, R.T., Survey of Augmented Reality. Presence: Teleoperators and Virtual Environments, 1997. 6.
2. Hollerer, T., et al., Exploring MARS: Developing Indoor and Outdoor User Interfaces to a Mobile Augmented Reality System. Computers and Graphics, 1999. 23(6): p. 779-785.
3. Feiner, S., et al., A Touring Machine: Prototyping 3D Mobile Augmented Reality Systems for Exploring the Urban Environment, in nternational Symposium on Wearable Computers. 1997, IEEE. p. 74-81.
4. Julier, S., et al. Bars: Battlefield augmented reality system. in NATO Symposium on Information Processing Techniques for Military Systems. 2000. Istanbul, Turkey.
5. Piekarski, W., et al., An Architecture for Outdoor Wearable Computers to Support Augmented Reality and Multimedia Applications, in Proceedings of the Third International Conference on Knowledge-Based Intelligent Information Engineering Systems. 1999, IEEE: Adelaide.
6. Thomas, B.H., et al. A wearable computer system with augmented reality to support terrestrial navigation. in In Second International Symposium on Wearable Computers. 1998. Pittsburgh: IEEE.
7. Thomas, B., et al. ARQuake: An outdoor/indoor augmented reality first person application. in Fourth International Symposium on WearableComputers. 2000. Atlanta, GA: IEEE.
8. Azuma, R.T. The Challenge of Making Augmented Reality Work Outdoors. in First International Symposium on Mixed Reality (ISMR '99. 1999. Yokohama, Japan: Springer-Verlag.

His experience includes 12 years at the School of Computer and Information Science, University of South Australia. He has run his own computer consultancy company, been a Computer Scientist at the National Institute of Standards and Technology (a major US government laboratory for the Department of Commerce), and a software engineer for the Computer Sciences Corporation and the General Electric Company.