Input Devices - University of Southern...
Transcript of Input Devices - University of Southern...
Input Devices
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Input devices
• Hardware that allows the user to communicate with the system
• Input device vs. interaction techniques
• Single device can implement many ITs
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Human-computer interface
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Human-VE interface
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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
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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, ...
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Practical classification system
• Desktop devices
• Tracking devices
• 3D mice
• Special-purpose devices
• Direct human input
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Desktop devices: keyboards
• Chord keyboards[1]
• Arm-mounted keyboards[2]
• “Soft” keyboards (logical devices)
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Desktop devices: 6-DOF devices
• 6 DOFs without tracking
• Often isometric
• Exs: SpaceBall, SpaceMouse, SpaceOrb
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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
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Other uses for trackers• Track hands, feet, etc.
• “whole body” interaction
• motion capture application
• Correspondence between physical/virtual objects
• props
• spatial input devices
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Tracking physical objects (props)
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Electromagnetic trackers
• Exs: Polhemus Fastrak, Ascension Flock of Birds
• Most common
• Transmitter
• Receiver(s)
• Noisy
• Affective by metal
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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
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Inertial trackers
• Exs: Intersense IS-300, Intertrax2
• Less noise, lag
• Drift problem
• Only 3 DOFs (orientation)
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Hybrid tracking
• Exs: IS-600/900
• inertial (orientation)
• acoustic (position)
• additional complexity, cost
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Tracking devices: eye tracking
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Tracking devices: bend-sensing gloves
• CyberGlove, 5DT
• Reports hand posture
• Gesture
• single posture
• series of postures
• posture(s) + location or motion
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Tracking devices: pinch gloves
• Conductive cloth at figuretips
• 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 selection
• tool section
• travel
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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 ||
• 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 SmartScence
• Lots of two-handed gestures
• scale / rotate world
• travel by “grabbing the air”
• Menu section
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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
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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
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3D mice
• Ring Mouse
• Wand
• Cubic Mouse
• Space Mouse
• ....
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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”
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Special-purpose devices: Painting table
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Special-purpose devices: shapeTape
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Human input: body sensing devices
• http://www.media.mit.edu/affect/
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Human input: speech• Frees hands
• Allows multimodal input
• No special hardware
• Specialized software
• Issues: recognition, ambient noise, training, false positives, ...
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Human input: bioelectric control
• NASA
• brain-body actuated control
• thoughts
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Locomotion devices
• Treadmills
• Stationary cycles
• VMC / magic carpet
• Walking / flying simulations (use trackers)
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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
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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
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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
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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
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Walk in place• Analyze tracker
information from head, body, feet
• Shown to be better than purely virtual movement, but worse than real walking
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Classification of locomotion devices / techniques
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Input and output with a single device
• Classic example - touch screen
• LCD tablets or PDAs with pen-based input
• Phantom haptic device
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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
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Conclusions• When choosing a device, consider:
• cost
• generality
• DOFs
• Ergonomics / human factors
• Typical scenarios of use
• Output devices
• Interaction techniques
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