ve input devices(i)
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VE Input Devices(I). Doug Bowman Virginia Tech Edited by Chang Song. Goals and Motivation. Provide practical introduction to the input devices used in VEs Examine common and state of the art input devices look for general trends spark creativity Advantages and disadvantages - PowerPoint PPT PresentationTRANSCRIPT
VE Input Devices(I)
Doug BowmanVirginia Tech
Edited by Chang Song
(C) 2005 Doug Bowman, Virginia Tech 2
Goals and Motivation
Provide practical introduction to the input devices used in VEs
Examine common and state of the art input devices look for general trends spark creativity
Advantages and disadvantages Discuss how different input devices affect interface
design
(C) 2005 Doug Bowman, Virginia Tech 3
Input devices
Hardware that allows the user to communicate with the system
Input device vs. interaction techniqueSingle device can implement many ITs
(C) 2005 Doug Bowman, Virginia Tech 4
Human-computer interface
SystemSoftwareU
ser i
nter
face
sof
twar
e
User
Inputdevices
Outputdevices
ITs
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Human-VE interface
Tracking system
Env. modelSimulation loop:-render-check for events-respond to events-iterate simulation-get new tracker data
Display(s)
Input device(s)
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Input device characteristics
Degrees of Freedom (DOFs) & DOF composition (integral vs. separable)
Range of reported values: discrete/continuous/hybrid
User action required: active/passive/hybrid Intended use: locator, valuator, choice, … Frame of reference: relative vs. absolute Properties sensed: position, motion, force, …
(C) 2005 Doug Bowman, Virginia Tech 7
Practical classification system
Desktop devices Keyboards, 2D mice and trackballs, pen-based tables, joysticks, 6DOF devices for the desktop
Tracking devices 3D mice Special-purpose devices Direct human input
(C) 2005 Doug Bowman, Virginia Tech 8
Desktop devices: keyboards
Chord keyboards1
Arm-mounted keyboards2
“Soft” keyboards (logical devices)
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Desktop devices: 6-DOF devices
6 DOFs without tracking
Often isometricExs: Fig. 4.4
SpaceBall 5000, SpaceMouse Plus, SpaceOrb
(C) 2005 Doug Bowman, Virginia Tech 10
Tracking Devices
Motion trackingEye trackingData Gloves
(C) 2005 Doug Bowman, Virginia Tech 14
Motion Tracking
Critical characteristics Range, latency, jitter (noise or instability), and
accuracy Different motion trackers
Magnetic Mechanical Acoustic Inertial Optical Hybrid
(C) 2005 Doug Bowman, Virginia Tech 15
Electromagnetic trackers
Exs: Polhemus Fastrak, Ascension Flock of Birds
Most common Used with conventional
monitors (for fishtank VR) Small workbench displays
Transmitter Receiver(s) Noisy Affected by metal objects ->
distort the magnetic field
(C) 2005 Doug Bowman, Virginia Tech 16
Inertial trackers
Inertial measurement devices : angular gyroscopes & linear accelerometer
Exs: Intersense IS-300, Intertrax2
Less noise, lag Only 3 DOFs (orientation)
(C) 2005 Doug Bowman, Virginia Tech 17
Optical/vision-based trackers
Reflected or emitted light Exs: Vicon, HiBall, ARToolkit Advantages
accurate can capture a large volume allow for untethered tracking
Disadvantages may require light emitting
diodes(LEDs) image processing techniques occlusion problem
(C) 2005 Doug Bowman, Virginia Tech 18
Optical/vision-based trackers
Outside-in or inside-out system Sensors/landmarks – tracked
objects/environment Setting up vision-based tracking
system can be difficult
(C) 2005 Doug Bowman, Virginia Tech 19
Hybrid tracking
Ex: IS-600 / 900 inertial (orient.) acoustic (pos.) additional
complexity, cost
(C) 2005 Doug Bowman, Virginia Tech 20
Tracking devices: eye tracking
(C) 2005 Doug Bowman, Virginia Tech 21
Tracking devices: eye tracking
User controlling a mouse pointer strictly with his eyes.
Gazed direction based
- Head-tracker as an approximation to where the user is looking. Problem can occur.
- Improve these gaze-directed techniques
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Tracking devices: bend-sensing gloves CyberGlove7, 5DT Reports hand posture Gesture:
single postureseries of posturesposture(s) + location or
motion
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Tracking devices: pinch gloves
Conductive cloth at fingertips
Any gesture of 2 to 10 fingers, plus combinations of gestures
> 115,000 gestures
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Case study: Pinch Gloves
Pinch gloves are designed to be a combination device (add a position tracker)
Very little has been done with Pinch Gloves in VEs - usually 1 or 2 gestures for:Object selectionTool selectionTravel
(C) 2005 Doug Bowman, Virginia Tech 25
Characteristics of Pinch Gloves
Relatively low costVery lightUser’s hand becomes the deviceUser’s hand posture can changeAllow two-handed interactionHuge number of possible gestures
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Characteristics of Pinch Gloves II
Much more reliable than data glovesSupport eyes-off inputCan diminish “Heisenberg effect”Support context-sensitive gesture
interpretation
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Pinch Gloves in SmartScene13
Lots of two-handed gesturesScale worldRotate worldTravel by “grabbing
the air”Menu selection
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Pinch Gloves for menus
TULIP system14
ND hand selects menu, D hand selects item within menu
Limited to comfortable gestures
Visual feedback on virtual hands
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Pinch Gloves for text input
Pinch Keyboard14
Emulate QWERTY Pinch finger to thumb to
type letter under that finger
Move/rotate hands to change active letters
Visual feedback
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Combining Bend-Sensing Data and Pinch Input
Both the Pinch Gloves and bend-sensing gloves have limitations
The Flex and Pinch input system is an example of an input device that combines the functionality of the Pinch Gloves system with the bend-sensing technology of a data glove
Figure 4.15