Virtual Reality
References:
- 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:
- Simulation information projected as an overlay on the real
world, through semi-opaque goggles.
( Real world seen "live". )
- Real-time video imaging incorporated into the simulated world,
via digital camera input.
( Real world seen indirectly via cameras. )
- 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 )
- 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
- Education
- Architectural
- Historical ( Archeology )
- Artistic