ne must look at a display screen," he said, "as a window through which one beholds a virtual world. The challenge to computer graphics is to make the picture in the window look real, sound real and the objects act real." Video MappingA variation of the WoW approach merges a video input of the user's silhouette with a 2D-computer graphic. The user watches a monitor that shows his body's interaction with the world. 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 this approach, the Mandala system. This system is based on a Commodore Amiga with some added hardware and software. A version of the Mandala is used by the cable TV channel Nickelodeon for a game show (Nick Arcade) to put the contestants into what appears to be a large video game. Immersive SystemsThe ultimate VR systems completely immerse the user's personal viewpoint inside the virtual world. These "immersive" VR systems are often equipped with a Head Mounted Display (HMD). This is a helmet or a facemask that holds the visual and auditory displays. The helmet may be free ranging, tethered, or it might be attached to some sort of a boom armature. A nice variation of the immerse systems uses multiple large projection displays to create a 'Cave' or room in which the viewer(s) stand. An early implementation was called "The Closet Cathedral" for the ability to create the impression of an immerse environment within a small physical space. The Holodeck used in the television series "Star Trek: The Next Generation" is afar term extrapolation of this technology. Tele-presenceTele-presence is a variation on visualizing complete computer generated worlds. This technology links remote sensors in the real world with the senses of a human operator. The remote sensors might be located on a robot, or they might be on the ends of WALDO like too...
