ve input devices(i) doug bowman virginia tech edited by chang song
TRANSCRIPT
(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 technique
Single device can implement many ITs
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Human-computer interface
SystemSoftware
Use
r in
terf
ace
soft
war
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, …
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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
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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
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Motion Tracking
Critical characteristics Range, latency, jitter (noise or instability), and
accuracy Different motion trackers
Magnetic Mechanical Acoustic Inertial Optical Hybrid
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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
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Inertial trackers
Inertial measurement devices : angular gyroscopes & linear accelerometer
Exs: Intersense IS-300, Intertrax2
Less noise, lag
Only 3 DOFs (orientation)
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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
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Optical/vision-based trackers
Outside-in or inside-out system Sensors/landmarks – tracked
objects/environment
Setting up vision-based tracking system can be difficult
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Hybrid tracking
Ex: IS-600 / 900
inertial (orient.)
acoustic (pos.)
additional complexity, cost
(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
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Characteristics of Pinch Gloves
Relatively low cost
Very light
User’s hand becomes the device
User’s hand posture can change
Allow two-handed interaction
Huge number of possible gestures
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Characteristics of Pinch Gloves II
Much more reliable than data gloves
Support eyes-off input
Can 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