input devices - university of southern...

Input Devices

Monday, October 3, 11

Input devices

• Hardware that allows the user to communicate with the system

• Input device vs. interaction techniques

• Single device can implement many ITs


Human-computer interface


Human-VE interface


Input device characteristics• Degrees of freedom (DOFs) & DOF

composition (integral/separable)

• Type of electronics: digital/analog

• Range of reported values: discrete/continuous/hybrid

• Data type of reported values: Boolean/integer/floating point


More input device characteristics

• User action required: active, passive, hybrid

• Method of providing information: push, pull

• Intended use: locator, valuator, choice

• Frame of reference: relative, absolute

• Properties sensed: position, motion, force, ...


Practical classification system

• Desktop devices

• Tracking devices

• 3D mice

• Special-purpose devices

• Direct human input


Desktop devices: keyboards

• Chord keyboards[1]

• Arm-mounted keyboards[2]

• “Soft” keyboards (logical devices)


Desktop devices: 6-DOF devices

• 6 DOFs without tracking

• Often isometric

• Exs: SpaceBall, SpaceMouse, SpaceOrb


Tracking devices: position trackers

• Measure position and/or orientation of a sensor

• Degrees of freedom (DOFs)

• Most VEs track the head

• motion parallax

• natural viewing


Other uses for trackers• Track hands, feet, etc.

• “whole body” interaction

• motion capture application

• Correspondence between physical/virtual objects

• props

• spatial input devices


Tracking physical objects (props)


Electromagnetic trackers

• Exs: Polhemus Fastrak, Ascension Flock of Birds

• Most common

• Transmitter

• Receiver(s)

• Noisy

• Affective by metal


Optical/vision-based trackers • Exs: vicon, HiBall, ARToolkit

• Advantages:

• accurate

• can capture a large volume

• allow for untethered tracking

• Disadvantages

• image processing techniques

• occlusion problem


Inertial trackers

• Exs: Intersense IS-300, Intertrax2

• Less noise, lag

• Drift problem

• Only 3 DOFs (orientation)


Hybrid tracking

• Exs: IS-600/900

• inertial (orientation)

• acoustic (position)

• additional complexity, cost


Tracking devices: eye tracking


Tracking devices: bend-sensing gloves

• CyberGlove, 5DT

• Reports hand posture

• Gesture

• single posture

• series of postures

• posture(s) + location or motion


Tracking devices: pinch gloves

• Conductive cloth at figuretips

• Any gesture of 2 to 10 fingers, plus combinations of gestures

• > 115,000 gestures


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 selection

• tool section

• travel


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


Characteristics of pinch gloves ||

• Much more reliable than data gloves

• Support eyes-off input

• Can diminish “heisenberg effect”

• Support context-sensitive gesture interpretation


Pinch gloves in SmartScence

• Lots of two-handed gestures

• scale / rotate world

• travel by “grabbing the air”

• Menu section


Pinch gloves for menus• Tulip system

• ND hand selects menu, D hand slects item within menu

• Limited to comfortable gestures

• Visual feedback on virtual hands

• rapMenu


Pinch glove for text input• Pinch keyboard

• Emulate QWERTY

• Pinch figure to thumb to type letter under that finger

• Move/rotate hands to change active letters

• Visual feedback


3D mice

• Ring Mouse

• Wand

• Cubic Mouse

• Space Mouse

• ....


Special-purpose devices: using conductive cloth

• Virtual toolbelt

• Used to select virtual tools

• Good use of proprioceptive cues

• Interaction slippers

• Step on displayed options

• Click heels to “go home”


Special-purpose devices: Painting table


Special-purpose devices: shapeTape


Human input: body sensing devices

• http://www.media.mit.edu/affect/


http://www.media.mit.edu/affect/

http://www.media.mit.edu/affect/

Human input: speech• Frees hands

• Allows multimodal input

• No special hardware

• Specialized software

• Issues: recognition, ambient noise, training, false positives, ...


Human input: bioelectric control

• NASA

• brain-body actuated control

• thoughts


Locomotion devices

• Treadmills

• Stationary cycles

• VMC / magic carpet

• Walking / flying simulations (use trackers)


UNIPORT• First locomotion device for U.S.

Army (1994)

• Proof-of-concept demonstration

• Developed in six weeks

• Difficult to change direction of travel

• Small motion such as side-stepping are impossible


Treadport• Developed in 1995

• Based on a standard treadmill with the user being monitored and constrained by mechanical attachment to the user’s waist

• User actually walks or jog instead of pedaling

• Physical movement is constrained to one direction


Omni-directional treadmill

• Most recently developed locomotion device for US Army

• Revolutionary device that enables bipedal locomotion in any direction of travel

• Consists of two perpendicular treadmills

• Two fundamental types of movement

• User / system initiated movement


Virtual Motion Controller

• Weight sensors in platform sense user’s position over platform

• Step in direction to move that direction

• Step further to go faster


Walk in place• Analyze tracker

information from head, body, feet

• Shown to be better than purely virtual movement, but worse than real walking


Classification of locomotion devices / techniques


Input and output with a single device

• Classic example - touch screen

• LCD tablets or PDAs with pen-based input

• Phantom haptic device


PDA as ideal VE device • Offers both input and output

• Supports UbiComp

• Has on-board memory

• Wireless communication

• Portable, light, robust

• Allows text / number input

• Can be tracked to allow spatial input


Conclusions• When choosing a device, consider:

• cost

• generality

• DOFs

• Ergonomics / human factors

• Typical scenarios of use

• Output devices

• Interaction techniques


input devices - university of southern...

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