Augmented Reality (AR) is a new technology that involves the overlay of computer graphics on the real world. AR is within a more general context termed Mixed Reality (MR), which refers to a multi-axis spectrum of areas that cover Virtual Reality (VR), AR, telepresence, and other related technologies.
Virtual Reality is a term used for computer generated 3D environments that allow the user to enter and interact with synthetic environments. The users are able to “immerse” themselves to varying degrees in the computers artificial world which may either be a simulation of some form of reality or the simulation of a complex phenomenon.
In telepresence, the fundamental purpose is to extend operator’s sensory-motor facilities and problem solving abilities to a remote environment. In this sense, telepresence can be defined as a human/machine system in which the human operator receives sufficient information about the tele-operator and the task environment, displayed in a sufficiently natural way, that the operator feels physically present at the remote site. Very similar to virtual reality, in which we aim to achieve the illusion of presence within a computer simulation, telepresence aims to achieve the illusion of presence at a remote location.
AR can be considered a technology between VR and telepresence. While in VR the environment is completely synthetic and in telepresence it is completely real, in AR the user sees the real world augmented with virtual objects.
Wearable devices, like Head-Mounted- Displays (HMD), could be used to show the augmented scene, but other technologies are also available.
The scene generator is the device or software responsible for rendering the scene. Rendering is not currently one of the major problems in AR, because a few virtual objects need to be drawn, and they often do not necessarily have to be realistically rendered in order to serve the purposes of the application.
When combining the real and virtual world two basic choices are available: optical and video technology. Each of them has some tradeoffs depending on factors like resolution, flexibility, field-of-view, registration strategies, among others.
Four major classes of AR can be distinguished by their display type: Optical See- Through, Virtual Retinal Systems, Video See-Through, Monitor Based AR and Projector Based AR.
The Augmented Reality technology has many possible applications in a wide range of fields, including entertainment, education, medicine, engineering and manufacturing.