Virtuelle Realität 1 Teil 3: VR – Eingabegeräte Virtuelle Realität Wintersemester 2007/08 Prof. Bernhard Jung Prof. B. Jung Virtuelle Realität TU Freiberg Overview Continuous input devices Tracker Data gloves Discrete & hybrid input devices Mouse-type input devices Miscellaneous Platforms Speech …
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Teil 3: VR – Eingabegeräte · Teil 3: VR – Eingabegeräte Virtuelle Realität Wintersemester 2007/08 Prof. Bernhard Jung Prof. B. Jung Virtuelle Realität TU Freiberg Overview
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User monitoring is the real-time monitoring of the participant's actions in a VR experience
Continuous tracking of user movements (body tracking). allows the system to render and display the virtual world from the user's egocentric perspective -- providing the effect of physical immersion.
Discrete user-initiated inputsallows the user to indicate to the system that an action should be takene.g. pressing a button or speaking a command to the system
100 updates/sec3 meters rangefrom base unitResolution<2 mmand <.2 degrees
Electronic unit(2 hours battery life)
Prof. B. Jung Virtuelle Realität TU Freiberg
Optical Trackerpassive
IR light reflecting markerCombined to unique spatial configuration per tracked position
activeIR light emitting markerSequential activation: trivial identification of single markersrequires cabling & batteries
2 or more IR camerasAdvantages
No interference with metalLow latencyHigh resolution
DisadvantagesLine of sight issues (more cameras help)
6DOF optical tracker by ART
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Optical Tracker
6DOF optical tracker by ART
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Real-Time Motion Capture
www.ptiphoenix.com
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Mechanical Tracker
Very accurate and preciseVery fastMechanical linkage places an unnatural inertia on the userMechanical linkage can prevent the user from moving to some locationsForce feedback can be integrated into the system
Video: HMD SutherlandBoomPhantom
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Uses ultrasoundTypical setup for 3 DOF
3 microphones1 speaker
Distance is inferred from the travel time for the sound
Triangulation allows the location of each microphone/speaker to be determined
AdvantagesNo interference with metalRelatively inexpensive
DisadvantagesLine of sight issuesSensitive to air temperature and certain noises
Logitech Fly Mouse
Acoustic Trackers
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Inertial trackers
Intersense IS-300Less noise, lagOnly 3 DOFs (orientation)Use gyroscopes and accelerometers
inexpensiveCan lose accuracy over time
a gyroscopesource: wikipedia
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E.g. Intersense IS-600 / 900inertial (orient.)acoustic (pos.)
E.g. Ascension HyBirdoptical (position + orientation)inertial (orientation)
Hybrid Trackers
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Prof. B. Jung Virtuelle Realität TU Freiberg
E.g. Nintendo Wii Remote optical position & orientation tracking
uses built-in one-megapixelimage sensor
+ stationary sensor bar with 8 IR LEDs
+ orientation tracking using acceleration/tilt sensors
Space MouseRing Mouse (pictured)Fly Mouse(pictured)
Mouse Type Devices
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SpaceballSpaceMouseSpaceOrb
Potentially tracked
SpaceNavigator
Stationary Devices
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3Dconnection SpacePilot
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The Cubic Mouse
Fraunhofer IMK, Bernd Fröhlich & John Plate
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Cubic Mouse
First 12 DOF input deviceTracks position and rotation of rods using potentiometers
Other shapes andimplementationspossible
Mini Cubic Mouse…
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Hinkley et al., 1994
Props
A physical object used to represent some manipulableobject in a virtual worldThe physical properties (shape, weight, texture, center of gravity, solidity) give a limited amount of haptic feedback, and often suggest how the device is used (e.g. putter) Real nature of props allows user to easily manipulate the object (e.g. hand it to another user).
Head propCar prop…
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Tracking & interaction with handheld devices
tracked PDA
tracked stylusbuttons + stylus + 6DOF trackingtablet PC
Object selection (left) and manipulation (right)
work by Stefan Conrad, 2007
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Platforms
Larger physical structures used to interface with virtual worlds (the place where the user sits or stands) Can themselves represent some portion of the virtual world Can be generic or specific Several common platform types
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Ring Platform
Generic Typically used with head-based displaysTypically has a waist-high rail surrounding the participant Often used with handheld props
Ascension Spacepad
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Kiosk Platform
Booth-like structure the user stands/sits at (like an arcade machine) Generally has physical controls mounted on it Often designed to be easily relocatable
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Ambulatory platforms
Treadmill or stair-stepping machine Designed to provide realistic travel through the virtual world Physical exertion through leg motion gives proprioceptic feedback
www.virtusphere.com
Onmidirectional Platformwww.vsd.bz
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Vehicle platforms
Designed to seem as though you are riding in the cockpit of some craft Realistic controls panels are provided Large flight simulators are a familiar example Often used in theme-park VR systems
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Input devices with Haptics
cyberglove with haptics
Haptic Workstation
Vibro-tactile feedback
All pictures: www.immersion.com
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www.measurand.com
Other input devices – Shape Tape
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Other input devices – Position Tracking for minimal invasive surgery
Ascension 3D Guidance™ Tracker
"3D Guidance tracks the position and orientation of one or more tiny sensors, enabling real-time guidance of medical instruments for minimally invasive, image-guided procedures. Sensors, ranging in diameter from 1.8 mm to 0.3 mm, are typically embedded in the distal tip of catheters, scopes and probes. Measurements are unaffected when used in close proximity to intravascular ultrasound arrays."www.ascension-tech.com
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Other input devices –Neural (muscular) tracking methods
Means of sensing body part movement relative to other body parts(e.g. curling the hand into a fist). Has not been explored to a large degree in VR systems
Prof. B. Jung Virtuelle Realität TU Freiberg
Audio Input - Speech Recognition
Speech is a natural means of communicating information Can complement other modes of interactionmulti-modal interaction
How does computer know you're talking to it? push-to-talk name-to-talk look-to-talk
Issues to considercontinuous vs. one-time recognitionchoice and placement of microphonetraining vs. no traininghandling of false recognitionsurrounding noise interference
Not good when speaking can interfere with other operations Very good when hands are occupied with other tasks