Friday, June 23, 2006

ATT: Augmented Reality (X2: A Digital Layer over Real World)

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Augmented reality (AR) is a field of computer research which deals with the combination of real world and computer generated data. At present, most AR research is concerned with the use of live video imagery which is digitally processed and "augmented" by the addition of computer generated graphics. Advanced research includes the use of motion tracking data, fiducial marker recognition using machine vision, and the construction of controlled environments containing any number of sensors and actuators.



History of AR

In the original publication (Wellner et al., 1993) which coined the term, (Computer-) Augmented Reality (abbreviated AR) was introduced as the opposite of virtual reality: instead of diving the user into a synthesized, purely informational environment, the goal of AR is to augment the real world with information handling capabilities. Others define VR as a special case of AR, in the sense that AR adds to what VR already does. Additionally, augmented reality is itself a special case of the more general concept of mediated reality (med-R), in the sense that mediated reality allows for the perception of reality to be augmented, deliberately diminished, or otherwise modified.

Pierre Wellner's digital desk (see also the video) can be considered as AR's seminal research work. On the digital desk, besides being subject to the laws of physics, real objects can now react to information streams they become sensitive to (people, the environment or other augmented objects creating those streams). In a semantic sense, AR allows physical objects to supplement their "ergotic" (physical) properties with a semiotic dimension.

AR as a transformative technology

For many of those interested in AR, one of its most important characteristics is the way in which it makes possible a transformation of the locus of interaction. The interactive system is no more a precise location, but the whole environment; interaction is no more understood as a face-to-screen exchange, but dissolves itself in the surrounding space and objects. Using an information system is no more exclusively a conscious and intentional act.

AR and ubiquitous computing

AR has clear connections with the Ubiquitous computing (abbreviated UC) and Wearable computers domains. Mark Weiser stated that "embodied virtuality", the original term he used before coining "ubiquitous computing", intended to express the exact opposite to the concept of virtual reality (Mark Weiser's personal communication, Boston, March 1993). The most salient distinction to be made between AR and UC is that UC does not focus on the disappearance of conscious and intentional interaction with an information system as much as AR does: UC systems such as pervasive computing devices usually maintain the notion of explicit and intentional interaction which often blurs in typical AR work such as Ronald Azuma's work. The theory of Humanistic Intelligence (HI), however, also challenges this semiotic notion of signifier and signified. In particular, HI is intelligence that arises from the human being in the feedback loop of a computational process in which the human is inextricably intertwined, and does not typically require conscious thought or effort. In this way, HI, which arises from wearable Computer Mediated Reality, shares a lot in common with AR.

As compared to UC, Ronald Azuma's definition is more focused and covers a subset of AR's original goal, but it has come to be understood as representing the whole domain of AR: Augmented reality is an environment that includes both virtual reality and real-world elements. For instance, an AR user might wear translucent goggles; through these, he could see the real world, as well as computer-generated images projected on top of that world. Azuma defines an augmented reality system as one that

  • combines real and virtual
  • is interactive in real time
  • is registered in 3D

This definition is now often used in some parts of the research literature (Azuma, 1997).


One example of AR is the yellow first-down line seen in television broadcasts of American football games. The real-world elements are the football field and players, and the virtual element is the yellow line, which is drawn over the image by computers in real time. (Note that this example is not an augmented reality according to the definition above, because there is no interactive element). Some other examples of AR applications include:

  • Interactive three-dimensional maps that could be collaboratively modified and analyzed (e.g., for prospecting)
  • Television broadcasts in which captions point out which cars in an auto race are where
  • Visualization of hidden features (e.g., a doctor could "see" the fetus inside the mother's womb)
  • Assisting difficult tasks (e.g., the system could "label" the parts of a system in order to facilitate the mechanic's work)
  • Teleconferencing with both real and virtual participants
  • Entertainment (allowing computer-generated imagery to interact with live entertainers)
  • Games (e.g., arquake)
  • LifeClipper
  • Characteroke

Popular Culture


Gunbuster, Neon Genesis Evangelion, Hoshi no koe and Martian Successor Nadesico amongst others depict 360° augmented reality cockpits that are used to display information.


  • Wellner, P., Mackay, W. & Gold, R. Eds. Special issue on computer augmented environments: back to the real world. Communications of the ACM, Volume 36, Issue 7 (July 1993).
  • Azuma, Ronald T. "A Survey of Augmented Reality." Presence: Teleoperators and Virtual Environments 6, 4 (August 1997), 355 - 385
  • Starner, T., Mann S., Rhodes B., Levine J., Healey J., Kirsch D., Picard R., Pentland A. "Augmented Reality Through Wearable Computing." Presence: Teleoperators and Virtual Environments 6, 4 (August 1997), 386-398
  • Ramesh Raskar, Spatially Augmented Reality, First International Workshop on Augmented Reality, Sept 1998
  • J. Pair, J. Wilson, J. Chastine, M. Gandy. "The Duran Duran Project: The Augmented Reality Toolkit in Live Performance." The First IEEE International Augmented Reality Toolkit Workshop, 2002.
  • S. K. Feiner. "Augmented Reality: A New Way of Seeing: Computer scientists are developing systems that can enhance and enrich a user's view of the world." Scientific American, April 2002
  • Oliver Bimber and Ramesh Raskar, Spatial Augmented Reality: Merging Real and Virtual Worlds, A K Peters, July 2005, 360 pages
  • Rolf R. Hainich, The End of Hardware - A Novel Approach to Augmented reality, Booksurge, March 2006, 248 pages


External links

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