Mixed Reality Continuum

Addressing some characteristics and mixed reality application types. AR concept relies on a mixed perception and since human beings have five senses: hearing, sight, touch, smell and taste, we may imagine that for each of them, we may have a mix between a direct perception and a computer mediated one. In a well-known example, proposed by Magic Vision Lab from University of South Australia, the virtual fish is augmenting the real world by using three modalities: visually, orally and haptically. The user may see the virtual fish, hear when it says “My name is Dory” and touch it by using a force feedback pen.

It is also true that the sense commonly augmented by the majority of AR applications today is the visual modality.

The precision of positioning the virtual object in the real scene is a very relevant aspect, some applications requiring very precise positioning. In these examples, the virtual brain is tightly registered on a real human body image for an AR assisted surgery, while for some other applications such as tourist guides, the information is overlaid less tightly over a straight scene.

Another relevant aspect in AR is the real time nature of the entire process.

Since the direct perception of the world is processed in real time, the computer mediated perception should also be done in real time and any delay that may occur here would have a negative impact on the overall experience.

The variety of MAR applications is also explained by the possibility to play with the amount of direct versus computer mediated perception.

Some applications may use few virtual objects

such as icons indicating some places like in the images

and some other applications may use 3D objects blended with the real 3D world and, therefore, improving the feeling of immersion in the mixed world. Therefore, we may classify the MAR application by using what is called the Mixed Reality Continuum, proposed by Paul Milgram in ’94. Between the two endpoints, the physical reality, which is only containing physical objects and the virtual reality, containing only virtual objects,

there is a continuum of cases

and two of them are the augmented reality, where computer generated content is added to the real world and augmented virtuality, where objects captured from the real world are added to a computer generated environment.