Augmented reality refers to the practice of introducing computer graphics into the real world. The usual method for doing this is "video-see-through" AR. The user wears a head-mounted-display with a camera mounted to the front (top right). The camera sees the world from the user's perspective, but the video-stream is modified so that extra objects are drawn in (right).

The major technical challenge is calculating the transformation between an object in the world and the head. This transformation allows us to draw graphics so that they appear to be stable and attached to the object in question. An interesting side-effect of this is that one can manipulate the computer graphics simply by manipulating the object they are attached to - this is called "tangible interaction"

The most common approach is to use a fiducial marker, which is a known pattern printed on a flat 2D plane. Most of the academic work that I was involved in was "natural feature tracking" - here we register the virtual content by tracking unprepared visual environments. This is useful for outdoors applications, such as annotating geographical environments (right), or when markers are not practical for other reasons.

Video-see-through AR setup and results


Annotation of natural environments for wearable computing

DOWNLOADABLE MEDIA

• Example Video for my tracking system (32 Mb, MPEG, Canada)
• Plane Based Natural Feature Tracking (4.26 Mb, MPEG, Asia)
• General Natural Feature Tracking (3.55 Mb, MPEG, Asia)
• General Natural Feature Tracking 2 (16Mb, AVI, Canada)
• Interesting art project using my marker tracking

PUBLISHED WORK

• S.J.D. Prince, K. Xu and A.D. Cheok. “Robust camera tracking for augmented reality based on planar homographies,” IEEE Computer Graphics and Applications Vol. 22, pp. 39-45, 2002.
• K. Xu, S. J. D. Prince, A. D. Cheok, Y. Qiu, and K. G. Kumar, “Visual Registration for Unprepared Augmented Reality Environments,” Journal of Personal and Ubiquitous Computing, Vol. 7, pp.287-298, 2004.
• A.D. Cheok, W. Wang, X. Yang, S.J.D. Prince, S.W. Fong, M. Billinghurst and H. Kato. “Interactive theatre experience in embodied and wearable mixed reality space,” International Symposium on Mixed and Augmented Reality, pp.59-68, 2002.
• K. Xu, A.D. Cheok, K. Chia and S.J.D. Prince. “Visual registration for geographical labeling in wearable computing,” International Symposium on Wearable Computing, pp. 109-116, 2002.
• A.D. Cheok , K. Krishnamoorthy and S.J.D. Prince. “Micro-accelerometer based hardware interfaces for wearable computer mixed reality applications,” International Symposium on Wearable Computing, pp. 223-230, 2002.
• K.W. Chia, A.D. Cheok and S.J.D. Prince. “Online 6 DOF augmented reality registration from natural features,” International Symposium on Mixed and Augmented Reality, pp. 305-313, 2002.