3D Visual Communications

9.5 Augmented Reality

Computer graphics provides a virtual environment (VE) to immerse a user into a synthetic environment but a user cannot actually see the world around him or her. Augmented reality (AR), a variation on VE, allows the user to see parts of the world with virtual objects added into the real world. Therefore, AR supports reality with the appearance of both real and virtual objects rather than replacing reality. AR also provides a middle ground between VE (completely synthetic) and telepresence (completely real) [24, 25]. AR can enhance the perception of a user to helps them perform real-world tasks with the assistance of the virtual objects. AR is defined by Azuma [26] as a system that has the following three characteristics:

1. combine real and virtual objects and scenes
2. allow the interaction with the real and virtual objects in real time
3. register interactions and objects in the 3D world

The fundamental functions provided by an AR system are the ability to add and remove objects to and from a real world and to provide haptics. Current research focuses on adding virtual objects into a real environment and blending virtual and real images seamlessly for display. However, the display or overlay should be able to remove and hide the real objects from the real world, too. Vision is not the only sense of a human. Hearing, touch, smell and taste are other senses which are also important hints for interaction with the scene. Especially touch can give the user the sense ...