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Location Watergraafsmeer - CAVE

Location:

SARA, Amsterdam

Contact:

Drs. P. Wielinga (wielinga@sara.nl)

About CAVE

CAVE

The CAVE is a 3m 3m 3m room, with three walls and a floor. Projectors, situated behind the walls, project computer-generated imagery onto the walls and floor. Two perspective-corrected images are drawn for each frame, one for the right eye and one for the left. Special glasses are worn that ensured that each eye sees only the image drawn for it. This creates a stereoscopic effect where the depth information encoded in the virtual scene is restored and conveyed to the eyes of those using it.

 

The CAVE works by reproducing many of the visual cues that the human brain uses to decipher the world around you. Information such as the differing perspectives presented by the eyes, depth occlusion, and parallax (to name a few) are all combined into the single composite image that you are conscious of, while the rest is decoded by one's brain to provide you with depth cues. The CAVE must reproduce all of this information in real-time, as you move about in the CAVE.

 

The CAVE provides true stereoscopic imagery through the use of four rear-projected screens using an active stereo system. Electrohome CRT projectors are used for the imagery and are bounced off of mylar mirrors so that the CAVE will fit within the constrained space of the room.. Infrared Crystal Eyes active stereo LCD shutter glasses are used in conjunction with the projectors to provide true stereo at an ideal rate of sixty frames per second (thirty frames per second for each eye). An eight-processor Silicon Graphics Onyx 2 Reality Monster powers the CAVE through four graphics boards (one for each wall). Wired tracking is provided through either Ascension Technology's Flock of Birds electromagnetic tracking.

The small distance between one's eyes means that each eye sees the world from a slightly different angle. The brain assembles these two images into a single composite image and uses the differences in perspective, along with other cues, to determine the depth of the scene. The CAVE recreates this effect by providing the right and left eyes with slightly different perspectives of the scene that mirror what they would see in real life. This provides the critical depth information that makes everything seem to "come alive" in the CAVE.

The special glasses weared in the CAVE are actually shutter glasses that make the right lens become opaque when the image for the left eye is being displayed and vice-versa, so that each eye only sees the image designed for it. The special tracked glasses and CAVE wand are both attached to electromagnetic sensors that allow the computer system to know where within the CAVE each is located and what its orientation is. The computer can use this information to general the proper viewpoint within the scene (so that you can peer around the corner of a building by physically moving your head). Occlusion and parallax, are calculated based on the location of the tracked glasses and the current eye being drawn for, providing unparalleled realism.

In the area of Virtual Reality SARA offers:

  • Consultancy
  • Assistance
  • Software development
  • Workshops/Projects
  •  

 

For further information please contact: SARA, Marketing and Sales Department, P.O. Box 94613, 1090 GP Amsterdam. Email: marketing@sara.nl.

Links

SARA

http://www.sara.nl

Insight

http://www.sara.nl/Virtual_Reality/index.html