Virtual Reality is a person-machine hub that allows a computer-generated reality that addresses a number of senses to be perceived as reality. "The Virtual Reality concept is mostly associated with a computer supported and generated copy of our real surroundings that is as sensor-motorically perfect as possible." (Hans-Jörg Bullinger)
Artificial Reality - VR without imersion
The user becomes an outside observer of an artificial world in Artificial Reality whereas Virtual Reality makes use of an immersive approach. Immersion requires that the user experience the artificial world as being real and technology to dissappear into the background entirely in the ideal case. This makes the degree of immersion a form of quality measurment for the virtual surroundings.
Augmented Reality is a variant of Virtual Reality in which virtual and real surroundings blend into one picture Reality is enhanced through otherwise invisible material increasing the effectiveness of perception of real circumstances.