What is Augmented Reality?

Augmented Reality is a term used to describe the use of technology that overlays information on the real world in real time with the idea of enhancing the user's current perception of the real world and creates an interactive experience.

Milgrem et al in 1994 proposed thatt Augmented Reality is part of a continuum.

On the two extremes there are the real and virtual envirnoments. In between the two extremes is a mixed reality. On the left of the continuum is Augmented Reality and on the right of the continuum is Augmented Virtuality, an example of which is Second Life. As Augmented and Virtual technologies continue to evolve in the mixed realtiy it may be harder to categorize the technology as AR or AV. SPIE Vol 2351, Telemanipulator and Telepresence Technologies pp 282-292.

The goal of Augmented Reality (AR) is to add information and meaning to a real object or place. Unlike virtual reality, augmented reality does not create a simulation of reality. Instead, it takes a real object or space as the foundation and incorporates technologies that add contextual data to deepen a person’s understanding of the subject. For example, by superimposing imaging data from an MRI onto a patient’s body, augmented reality can help a surgeon pinpoint a tumour that is to be removed. In this case, the technology used might include headgear worn by the surgeon combined with a computer interface that maps data to the person lying on the operating table. In other cases, augmented reality might add audio commentary, location data, historical context, or other forms of content that can make a user’s experience of a thing or a place more meaningful.Educause
Augmented reality (AR) according to Ronald Azuma, Research Leader at Nokia Research Centre 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 goes on to say that, “Augmented Reality is a variation of Virtual Environments (VE), or Virtual Reality as it is more commonly called. VE technologies completely immerse a user inside a synthetic environment. While immersed, the user cannot see the real world around him. In contrast, AR allows the user to see the real world, with virtual objects superimposed upon or composited with the real world. Therefore, AR supplements reality, rather than completely replacing it. Ideally, it would appear to the user that the virtual and real objects coexisted in the same space.Azuma R.
According to the 2011 Horizon Report, Augmented reality refers to the addition of a computer-assisted contextual layer of information over the real world, creating a reality that is enhanced or augmented.