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

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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, …

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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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Tracking Devices

Motion trackingEye trackingData Gloves

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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

(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

(C) 2005 Doug Bowman, Virginia Tech 26

Characteristics of Pinch Gloves II

Much more reliable than data glovesSupport eyes-off inputCan diminish “Heisenberg effect”Support context-sensitive gesture

interpretation

(C) 2005 Doug Bowman, Virginia Tech 27

Pinch Gloves in SmartScene13

Lots of two-handed gesturesScale worldRotate worldTravel by “grabbing

the air”Menu selection

(C) 2005 Doug Bowman, Virginia Tech 28

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

(C) 2005 Doug Bowman, Virginia Tech 30

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