A concise introduction to AR

What is Augmented Reality?

Augmented Reality (AR) is a variation of Virtual Reality (VR) (also know as Virtual Environments (VE)). To „augment“ means to supplement. Accordingly, AR suppliments reality with virtual, computer-generated imagery. As opposed to VR, where the user sees only the virtual world, AR allows users to see virtutal objects in a real-world environment. „Augmented Reality enhances a user’s perception of and interaction with the real world“ (Azuma, 1997, p. 3). For those familiar with the movie „Who Framed Roger Rabbit“, one could say the well-functioning AR should achieve the level of fluent blending of the real with the virtual as exhibited in this movie. (Azuma, 1997)

Milgram’s reality-viruality continuum

In the famous paper „Augmented Reality: A Class of Displays in the reality-virtuality-continuum“, Milgram, Takemura, Utsumi & Kishino (1994) introduce the different components of what they call Mixed Reality, placing AR one step down the line moving from the Real Environment to a totally Virtual Environment, as shown in the figure below:

AR on the RV continuum

A visualisation of AR

Azuma, in his fundamental piece „A Survey of Augmented Reality“, uses the following figure to visualise what it may look like when synthetic 3-D objects are placed in a real 3-D environment, explaining that they are „combined in 3-D, so that the virtual lamp covers the real table and the real table covers parts of the two virtual chairs“ (Azuma, 1997, p. 2). In the figure, the lamp and table are virtual, whereas both the table and phone are real life objects.

Real desk with virtual lamp and two virtual chairs

Defining AR

In his survey, Azuma (1997, p. 2) defines AR as having „the following three characteristics:

1. Combines real and virtual
2. Interactive in real time
3. registered in 3-D“

He justifies this definition by explaining that it does not limit AR to specific technologies, such as Head-Mounted-Displays (HMDs), but at the same time rules out film or 2-D overlays because they either lack interactivity, such as the film „Jurrasic Park“, or the feature of having been combined with the real world in 3-D (demonstrated in the figure 2 above). With his definition, Azuma leaves the real of AR open to a number of technologies, such as monitor-based interfaces, monocular systems and see-through HMDs (Azuma, 1997).

What good is it to start „mixing realities“? Find out more about how AR can help people of various professions to perform real-world tasks in the diverse fields of application of AR.