Virtual reality
Virtual realityVirtual Reality
Virtual reality, is a computer-generated, multi-sensory human interface to computers. Virtual reality extends beyond the capability of typical workstation graphics in two ways. First, through the use of tracking sensors, the computer knows precisely the location and angle of the user's head, which enables the graphics scene to be generated in the correct perspective for each eye. Second, because a very wide-angle image is provided, which is updated 10 to 60 times a second and is often augmented with synthesized surround sound, motion, and even scent, a level of immersion in the simulated scene is achieved. Immersion, combined with correct perspective, allows the development of facile methods for navigation in three dimensions. (Gump)
Scene complexity is determined by the computer system's capability to display a great number of shaded, lighted, textured, and occluded polygons necessary to visually describe the many objects in the scene. Change to the scene is governed by the computer simulation program or database driving the creation of the scene. Thus the visual quality of a VR experience is dependent on the speed of both the graphics-rendering hardware/software and the computer system itself. (Gump)
There are four major types of virtual reality devices currently in use: the head-mounted display (HMD), the binocular omni-oriented monitor (BOOM), the workstation "desktop" model (DEERING), and the projection model (CAVE). The HMD is a tracked helmet worn by the user that provides small television screens properly placed in front of the eyes. Although modest in comparison with other VR devices, it is not lightweight enough to prevent fatigue, and the screen resolution is typically medium at best. The BOOM also uses small television screens, but the angle of view is improved by wide-angle optics. The screens are suspended from a mechanical arm articulated in five dimensions that eliminates the weight of the HMD and provides accurate tracking over its range of operation. The desktop model uses a standard workstation screen outfitted with stereo liquid crystal display (LCD) shutter glasses synchronized with the screen so that each eye's view, drawn in correct perspective, is presented to that eye only. The disadvantage is a limited field of view, but this can be partially overcome by using a much larger projection screen in front of the user, the goal being to get the edges of the screen out of view. (Warrick)
The CAVE is a room 3 by 3 by 3 meters (10 by 10 by 10 feet) constructed of at least two walls and a floor made of projection screens. It has a very wide field of view and high resolution and provides a rather complete feeling of immersion. Since the CAVE is large and two to four times as expensive as the other models, it is not an office device. However, since it allows multiple participants at once (only one is tracked), the CAVE can be used in sales, teaching, and presentation contexts. (Benedickt)
The field of virtual reality is in its...
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