Virtual Reality

References:

1. This information comes from many many sources and years of experience.

Overview:

• JTB's Definition: "Virtual Reality is an interactive immersive 3D computer generated simulation, designed to make the user believe, to the greatest extent possible, that they are actually experiencing a real environment." Obviously some implementations achieve this goal to a greater or lesser extent.
• Andy Johnson's CS 528 pages are available on-line.
• The top VR conference is IEEE VR - Both the 2005 conference and 2006 conference pages are available online. The proceedings can be found via the IEEE Digital Library.
• Key properties of VR:
  • Degree of immersion - The extent to which the user feels they are within the simulated environment, as opposed to an external observer.
  • Degree of presence - The extent to which the user believes they are really there in the simulated environment, and forget that it is just a simulation. ( Note that even a good book can have a high degree of presence, when the reader becomes totally engrossed in it. )
  • Suspension of disbelief - The extent to which the user turns off their disbelief, or skepticism, and buys into what the simulation is telling them. Similar to watching a movie, and ignoring for a while that what they are presenting on the screen has lots of flaws and impossibilities.
• Augmented Reality, AR, combines displays of the simulated world with views of the real world:
  1. Simulation information projected as an overlay on the real world, through semi-opaque goggles. ( Real world seen "live". )
  2. Real-time video imaging incorporated into the simulated world, via digital camera input. ( Real world seen indirectly via cameras. )
  • Wayne Piekarski, Ben Avery, Bruce H. Thomas, and Pierre Malbezin, “Integrated Head and Hand Tracking for Indoor and Outdoor Augmented Reality”, IEEE VR 2004, Chicago, IL. ( Further information and images, including this demo movie, are available at the Tinmith web site. )

• The key components of the VR Execution Loop are typified by the following flowchart, taken originally from the WorldToolKit manual:

Key Components of VR Simulations:

• Visual Display
  • Standard Monitor
  • Stereo Monitor
    • Red-Blue glasses
    • Crystal Eyes glasses
    • Cyberscope - Split hood with mirrors.
  • Head-Mounted Display
  • Fakespace BOOM
  • Polarized projectors
  • Rear-projected stereo walls ( CAVE )
• Audio display ( & input )
  • 3D spatialized sound
• Trackers
  • May track the head, hand, or anything else
    • Typically built in to or added onto a head-mounted display, so that the viewpoint can be updated dynamically as the user shifts their gaze.
    • Some HMD trackers are 3 DOF only ( tilt sensors ) instead of full 6 DOF.
  • Accoustic
  • Electromagnetic
  • Other
• Handheld manipulators, e.g. wands, joysticks, etc.
• Flex sensors
  • Typically used for sensing finger movements
  • May also be used to sense other joints, e.g. elbows, knees, etc.
  • Fiber-optics are the most common, measuring the reduced light transmission through the fiber when it is bent.
  • The cheap Nintendo cyberglove used variable-resistive inks.
• Force feedback & haptics
  • Tactile - lets the user "feel" the wall, but doesn't prevent the user from putting their hand through it.
  • Force-feedback - Physicaly restrains the user and limits their movement. May provide variable resistance or complete motion prohibition.
• Other sensations - Olfactory, vibration seats, etc.
• Other inputs - bio sensors, remote equipment sensors, etc.
• Network connectivity for collaborative applications

Noteworthy VR Application Areas

• Gaming
• Military
• Medicine
  • Larry Hodges' "Virtually Better" & related works, using VR to aid in the treatment of phobias:

• Education
• Architectural
• Historical ( Archeology )
• Artistic