What is Virtual Reality? The term Virtual Reality (VR) is used by many differentpeople and currently has many meanings. There are some people to whom VR is aspecific collection of technologies, that is a Head Mounted Display, Glove InputDevice and Audio.
However, the general concept of the systems goes way beyondthat. "Virtual Reality is a way for humans to visualize, manipulate andinteract with computers and extremely complex data" The visualization partrefers to the computer generating visual, auditory or other sensual inputs. Theimages are graphical renderings of a world within the computer. This world maybe a CAD model, a scientific simulation, or a view into a database. The user caninteract with the world and directly manipulate objects within the world. Someworlds are animated by other processes, perhaps physical simulations, or simpleanimation scripts.
Some people object to the term "Virtual Reality",saying it is an oxymoron. Other terms that have been used are SyntheticEnvironments, Cyberspace, Artificial Reality, Simulator Technology, etc. VR isthe most common and sexiest. It has caught the attention of the media. Theapplications being developed for VR run a wide spectrum, from games to buildingand business planning. Many applications are worlds that are very similar to ourown, like CAD or architectural modeling.
Some applications provide ways ofviewing from an advantageous perspective not possible with the real world, likescientific simulators and telepresense systems, air traffic control systems.Other applications are much different from anything we have ever directlyexperienced before. These latter applications may be the hardest, and mostinteresting systems. Visualizing the ebb and flow of the world's financialmarkets. Navigating a large corporate information base, etc.
A major distinctionof VR systems is the mode with which they interface to the user. There are somenon-technologically mediated methods that some people stretch to include in VR,such as books, plays, movies or pure imagination. The above mentioned taxonomycan include these, but we wish to restrict VR to technology mediated systems.Some systems use a conventional computer monitor to display the visual world.This sometimes called desktop VR or a Window on a World (WoW).
This concepttraces its lineage back through the entire history of computer graphics. In1965, Ivan Sutherland laid out a research program for computer graphics in apaper called "The Ultimate Display" that has driven the field for thepast nearly thirty years. One must look at a display screen, he said, as awindow through which one beholds a virtual world. The challenge to computergraphics is to make the picture in the window look real, sound real and theobjects act real. [quoted from Computer Graphics V26#3] A variation of the WoWapproach merges a video input of the user's silhouette with a 2D computergraphic. The user watches a monitor that shows his body's interaction with theworld.
Myron Kruger has been a champion of this form of VR since the late 60's.He has published two books on the subject: "Artificial Reality" and"Artificial Reality II". At least one commercial system uses thisapproach, the Mandala system. This system is based on a Commodore Amiga withsome added hardware and software. A version of the Mandala is used by the cableTV channel Nickelodeon for a game show (Nick Arcade) to put the contestants intowhat appears to be a large video game.
Immersive Systems is the ultimate VRsystems, completely immerse the user's personal viewpoint inside the virtualworld. These "immersive" VR systems are often equipped with a HeadMounted Display. This is a helmet or a face mask that holds the visual andauditory displays. The helmet may be free ranging, or it might be attached tosome sort of a boom armature.
A nice variation of the immersive systems usemultiple large projection displays to create a 'Cave'. An early implementationwas called "The Closet Cathedral" for the ability to create theimpression of an immense environment. within a small physical space. TheHolodeck used in the television series "Star Trek: The NextGeneration" is an extrapolation of this technology. A variation onvisualizing complete computer generated worlds is "Telepresence". Thisis a technology that links remote sensors in the real world with the senses of ahuman operator.
The remote sensors might be located on a robot, or they might beon the ends of WALDO like tools. Fire fighters use remotely operated vehicles tohandle some dangerous conditions. Surgeons are using very small instruments oncables to do surgery without cutting a major hole in their patients. Theinstruments have a small video camera at the business end. Mixed Reality Mergingthe Telepresence and Virtual Reality systems gives the Mixed Reality or SeamlessSimulation systems.
Here the computer generated inputs are merged withtelepresence inputs and the users view of the real world. A surgeon's view of abrain surgery is overlaid with images from earlier CAT scans and real-timeultrasound. A fighter pilot sees computer generated maps and data displaysinside his fancy helmet visor.BibliographyWalrath, Kathy. Performance Computing Magazine: Full Throttle, Feb 1999 Hall,Jon.
Cio WebBusiness Magazine: TomorrowLand, Dec 1998 Kalin Sari. PC Magazine:VR Fever, Nov 1998
