Augmented reality is a
new field of research that concentrates on integrating virtual objects into the real world. These virtual objects are computer graphics displayed so that they merge with the real world. Although in its infancy, Augmented reality holds out the promise of enhancing people’s ability to perform certain tasks. As sensing and computing technologies advance, augmented reality is likely to come to play a significant role in people’s daily lives.
An augmented-reality system merges the real scene viewed by the user with computer-generated virtual objects to generate a composite view for the user. The virtual objects supplement the real scene with additional and useful information. Sounds may be added through the use of special headphones that allow the user to hear both real sounds and synthesized sounds. There are also special gloves that a user can wear that provide tactile sensation such as hardness or smoothness. A user wearing such gloves could “feel” virtual furniture in a real room. In an augmented-reality system, users can walk around a real room, hear the echo of their footsteps, and feel the breeze from an air conditioning unit, while at the same time they can see computer-generated images of furniture or paintings.
One of the requirements of an augmented-reality system is that it needs to be interactive in real time. Animation, sound, and textures are added in real time so that what the user sees, hears, and feels reflects the true status of the real world. The most important characteristic of augmented reality is the ability to render objects in three-dimensional space, which makes them much more realistic in the eyes of the user.Virtual objects are drawn in relationship to the real objects around them, both in terms of position and size. If a virtual object is situated partially behind a real object (or vice versa) then the user should not see part of the obscured object.Occlusion of objects is the largest contributor to human depth perception.
The major difference between augmented reality and virtual reality is that in virtual reality everything that is sensed by the user is computer generated. Therefore the virtual objects must be rendered as photorealistically as possible in order to achieve the feeling of immersion. Augmented reality uses both real and synthetic sights, sounds, and touches to convey the desired scene, so virtual objects do not bear the entire burden of persuading the user that the scene is real, and therefore they do not need to be so photorealistic. Augmented reality lies in the middle of the continuum between absolute reality (in which everything sensed is real) and virtual reality (in which everything that is sensed is created).