Post on 12-Sep-2021
Realtime 3D Computer GraphicsVirtual Reality
Virtual Reality Input Devices
Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik
VR input devices! Special input devices are required for interaction,navigation and
motion tracking (e.g., for depth cue calculation):
1. Motion Trackers: Position and orientation of a reference system in 3D requires to measure 6 Degrees of Freedom (DOFs).
2. 3D Mice/Wands etc. : Specialized devices for point and click WIMP1-style metaphors have to account for additional DOFs.
3. Joint sensors: Sensors which measure movement of user’s joints (Also possible with trackers and inverse kinematics).
4. Props: Real placeholders for virtual objects.5. Movement effect sensors: Measure the effect user movement
has to the surrounding (no kinematics involved).6. Skin sensors, neural interfaces, bio-sensors: Measure skin
resistance, brain activity and other body related data.
…and hybrid devices.1WIMP: Windows, Icons, Menu, Pointer
Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik
VR input devicesInput is measured by a multitude of physical and biological
principles, e.g.,1.electro-magnetism2.optics (marker/marker less, visible spectrum/infrared)3.electrics (voltage, impedance, electrical flow,…)4.acoustics (ultrasound,…)5.inertia
Input devices produce data...•...discrete event based
(buttons, state changers).•...continuously
(discrete but continuously sampled).
Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik
VR input devices
6DOF Magnetic tracker & DataGlove
• Electromagnetic tracker• used to be most common
see: “put-that-there” (Bolt, 1980)• Transmitter
• Creates three orthogonal low-frequency magnetic fields
• Short range version: < 1m• Long range version: < 3m
• Receiver(s)• Three perpendicular antennas. • Distance is inferred from the
currents induced in the antennas.
- Noisy – requires filtering.- Affected by metal – requires non-linear
calibration.- Wireless versions expensive.
Transmitter
Receiver
Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik
• Inertial trackers !(Intersense IS-300)
+ Less noise, lag- Only 3 DOFs (orientation)• Use gyroscopes and accelerometers
• Hybrid trackers(e.g.,Intersense IS-600/900)
• inertial (orientation)• acoustic (position)
• Acoustic trackers• Uses ultrasound• Typical setup for 3 DOF:
3 microphones and1 speaker• Distance is inferred from the
travel time of the sound+ No interference with metal+ Relatively inexpensive- Line of sight issues- Sensitive to air temperature
and certain noises Logitech Fly Mouse
VR input devices
Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik
VR input devices
• Optical marker based tracker• marker reflects IR light• Combined to unique spatial
configuration per tracked position+ No interference with metal+ Low latency+ High resolution- Line of sight issues
(more cameras help)
6DOF optical tracker by ART
Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik
• 3D mice/wands• Several buttons and sensors
for selection of binary states and/or continuous state changes (e.g., potentiometers).
• Often hybrid devices for additional position/orientation.
VR input devices
tracked wand
space orb
ring mouse
Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik
VR input devices• CubicMouseTM
• First 12 DOF input device• Tracks position and rotation of rods
using potentiometers• Other shapes and
implementationspossible
• Mini Cubic Mouse• …
pictures courtesy of IMK Fraunhofer Gesellschaft
Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik
Sensors: 20/suit
100 updates/sec3 meters rangefrom base unitResolution<2 mmand <.2 degrees
Electronic unit(2 hours battery life)
Wireless suit (Ascension Technology)
VR input devices• Data Gloves
• Used to track the user’s finger movements.
• For posture and gesture detection.• Almost always used with a tracker
sensor mounted on the wrist• Common types:
• Body suites • Used to track the overall body
movement• Angles measured by resistance or• by inverse kinematics based on certain
body points
5DT Glove (left)5/16 sensors
• CyberGlove (right)• 18/22 sensors
• here hybrid modification for flexion and pinch
Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik
Head-propCourtesy of Hinkley et al.
VR input devices
ShapeTape-propcourtesy of Balakrishnan et al.
Cyberglove with haptics
Treadmill types(e.g. bicycles)
! …all the preceding and/or Speech Input
• continuous vs. one-time recognition• choice and placement of microphone• training vs. no training• handling of false positive recognition• surrounding noise interference• Can complement other modes of interaction
! " multi-modal interaction (by, e.g., additionally including gesture processing which benefits from the VR sensory equipment)
Fiktion: Interaktion
Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik
The Ultimate Display
„The ultimate display would, of course, be a room within which the computer can control the existence of matter. A chair displayed in such a room would be good enough to sit in. Handcuffs displayed in such a room would be confining, and a bullet displayed in
such room would be fatal. With appropriate programming such a display could literally be the
Wonderland into which Alice walked.“
(Sutherland 1965)
Fiktion: Interface für das „Ultimate Display“?
Fiktion: Results of physical contact
Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik
References• Bolt, R. A. (1980): Put That There: Voice and Gesture at the Graphics Interface.
In: Computer Graphics 14/3, (pp. 262-270)• Bühl, Achim (1997): Die virtuelle Gesellschaft. Politik, Ökonomie und Kultur im Zeichen des Cyberspace.
In: Gräf, Lorenz/ Krajewski, Markus (Hrsg.): Soziologie des Internet. Handeln im elektronischen Web-Werk, Frankfurt/M. /New York: Campus, 39-59.
• Gibson, William (1984): Neuromancer (first print)• Gibson, William (1999): Neuromancer, 9. Aufl., München: Heyne 1999 • Okoshi, T. (1976): Three-Dimensional Imaging Techniques, Academic Press, New York. • Peters, G. (2000). Theories of Three-Dimensional Object Perception - A Survey. Recent Research
Developments in Pattern Recognition, Transworld Research Network.• Sutherland, I.E. (1968): A Head-Mounted Three-Dimensional Display.
In: AFIPS Conference Proceedings, Vol. 33, Part I, pp. 757-764.