24-02-2012, 03:51 PM
virtual reality
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Definition by psychological effects
Using a psychological or behavioral framework one can define four progressive levels of virtual reality
level one virtual reality
it is a computer-generated environment wherein human participants do not act like they are in the real world and never forget that they are not in the real world.
HMD
HMD is an acronym for Head Mounted Display, which is a set of goggles or a helmet with tiny monitors in front of each eye that generates images seen by the wearer as being three dimensional. A true HMD includes a device for tracking the users head movements and orientation. In other words, it tracks what direction the user is looking. Most HMDs will track yaw, roll, and pitch and some will even track the users head translations, a full six degrees of freedom (6 DOF).
Many HMDs also have 3D sound headsets as part of the unit. Unconstrained objects have six different directions or rotations they are able to move within including forward or backwards, up or down, and left or right; these are called translations. Objects can also rotate around the principal axes, which is roll, yaw, and pitch.
This method makes use of a stereoscopic analysis, correlating pixels common to two images, seen by two offset cameras. As with ultrasounds, this technique requires an unobstructed line-of-sight so that the cameras can "see" the dots to be triangulated into 3D spatial positions. The triangulation consists of correlating given points on two images.
By this method that provides users total intuitive interaction with 3D and virtual environments, such as games, websites and educational software
