Post on 21-Dec-2015
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Communication through head movements
Communication through head movements
Juha Pieviläinenjuha.pievilainen@iki.fi
Alternative communication & access to information seminar 2003
Department of Computer Sciences
University of Tampere
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• Software
Content
• Tracking technologies
• Introduction
• Devices
• References
• Interaction style
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Introduction
”Computer users who cannot use a conventional hand-operated computer mouse and/or keyboard, may use a head operated mouse or keyboard in order to control their computer and, by using an on-screen keyboard, to type information.”
[5] A Head Operated Joystick – Experience with use, G. Evans and P. Blenkhorn, CSUN 99, available at
http://www.csun.edu/cod/conf/1999/proceedings/session0019.htm
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Introduction
Navigating virtual environments and more often playing games require a way to control field of vision. Keyboards, mice and joysticks might do the job, but they really are NOT natural way to change ones field of vision, turning ones head is.
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Tracking technologies
• mechanical• magnetic• sourceless, non-inertial• optical• acoustic (ultrasound)• inertial
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Technologies - mechanical
Description Strengths WeaknessesMeasure change in position by physically connecting the remote object to a point of reference with jointed linkages
Accurate
Low lag
No line of sight or magnetic interference problems
Good for tracking small volumes accurately
Intuitive, due to tethering
Subject to mechanical part wear-out
[2] Review of Virtual Environment Interface Technology, C. Youngblut, R.E. Johnson, et al., Institute for Defence Analyses, available at http://www.hitl.washington.edu/scivw/scivw-ftp/publications/IDA-pdf/
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Technologies - magnetic
Description Strengths WeaknessesUse sets of coils (in a transmitter) that are pulsed to produve magnetic fields. Magnetic sensors (in receiver) determine the strenght and angles of the fields. Pulsed magnetic field may be AC or DC
Inexpencive
Accurate
No line of sight problems
Good noise immunity
Map whole body motion
Large ranges – size of small room
Ferromagnetic and/or metal conductive surfaces cause field distortion. Electromagnetic interference from radios.
Accurace diminishes with distance
High latencies due to filtering
[2] Review of Virtual Environment Interface Technology, C. Youngblut, R.E. Johnson, et al., Institute for Defence Analyses, available at http://www.hitl.washington.edu/scivw/scivw-ftp/publications/IDA-pdf/
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Technologies – sourceless, non-inertial
Description Strengths WeaknessesUse passive magnetic sensors, referenced to the earth’s magnetic field, to provide measurement of roll, pitch, and yaw, and as a derivative, angular acceleration and velocity
Inexpensive
Transmitter not necessary
Portable
Only 3 DOF
Difficult to mark movement between magnetic hemispheres
[2] Review of Virtual Environment Interface Technology, C. Youngblut, R.E. Johnson, et al., Institute for Defence Analyses, available at http://www.hitl.washington.edu/scivw/scivw-ftp/publications/IDA-pdf/
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Technologies - opticalDescription Strengths Weaknesses
Use a variety of detectors, from ordinary video cameras to LEDs, to detect either ambient light or light emitted under control of the position tracker. Infrared light is often used to prevent interference with other activities
High availability
Can work over large area
Fast
No magnetic interference problems
High accuracy
Line of sight necessary
Limited by intensity and coherence of light sources
Weight
Expensive
[2] Review of Virtual Environment Interface Technology, C. Youngblut, R.E. Johnson, et al., Institute for Defence Analyses, available at http://www.hitl.washington.edu/scivw/scivw-ftp/publications/IDA-pdf/
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Technologies – acoustic (ultrasound)
Description Strengths WeaknessesUse three microphones and three emitters to compute the distance between a source and receiver via triangulation. use ultrasonic frequencies (above 20 kHz) so that the emitters will not be heard
Inexpensive
No magnetic interference problems
Lightweight
Ultrasonic noise interference
Low accuracy since speed of sound in air varies with environmental conditions
Echoes cause reception of ”ghost” pulses
Line of sight necessary
[2] Review of Virtual Environment Interface Technology, C. Youngblut, R.E. Johnson, et al., Institute for Defence Analyses, available at http://www.hitl.washington.edu/scivw/scivw-ftp/publications/IDA-pdf/
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Technologies - intertial
Description Strengths WeaknessesUse accelerometers and gyroscopes. Orientation of the object is computed by jointly intergrating the outputs of the rate gyros whose outputs are proportional to angular velocity about each axis. Changes in position can be computed by double intergrating the outputs of the accelerometers using their known orientation
Unlimited range
Fast
No line of sight problems
No magnetic interference problems
Senses orientation directly
Small size
Low cost
Only 3 DOF
Drift
No accurate for slow position changes
[2] Review of Virtual Environment Interface Technology, C. Youngblut, R.E. Johnson, et al., Institute for Defence Analyses, available at http://www.hitl.washington.edu/scivw/scivw-ftp/publications/IDA-pdf/
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Technologies - StatusMechanical Inertial Acoustic
Military uses
Situations when low cost system needed
Poor static accuracy problems need to be solved
Commercial products are available
Optical MagneticMature technology
Military versions in-use
Mature technology
Military versions in-use
Need accuracy improvement before implementation of HUD makes sense
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Interaction style
Absolute pointing vs. relative pointing
similar to mouse similar to joystick
[5] A Head Operated Joystick – Experience with use, G. Evans and P. Blenkhorn, CSUN 99, available at
http://www.csun.edu/cod/conf/1999/proceedings/session0019.htm
require good head control skills
less precise control needed
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Devices – Tracker 2000
• optical head tracker• choice between
mouse and joystick mode
• 8 directions• different button types
available, physical buttons, sip/puff straw or optical switch
[1] 100 % Hands-free Computer Access – Madentec’s 2000 series, R. Marsden, P.Eng., Madentec Limited, available at http://www.madentec.com/products/comaccess/2000/whitepaper.html
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Devices – ADL-1
• mechanical head tracker
• serial connection• cost around 1200 $
[2] Review of Virtual Environment Interface Technology, C. Youngblut, R.E. Johnson, et al., Institute for Defence Analyses, available at http://www.hitl.washington.edu/scivw/scivw-ftp/publications/IDA-pdf/
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Devices – Smart-Nav
• optical head tracker• replaces mouse• price ranging
between 129 to 299 $
[3] Eye Control Technologies, Inc. webpage at http://www.naturalpoint.com
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Software – SymbolCreator
• at the moment on experimental status
• typing by selecting icons
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Software – SoftType• Text entry into all standard Windows applications • Clicking done by dwell selection • Different keyboard layouts available • Word prediction
[6] Origin Instruments Corporation webpage at http://orin.com/index.htm
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Software – SoftType
[6] Origin Instruments Corporation webpage at http://orin.com/index.htm
A more simple layout for kids
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Software – SoftType
[6] Origin Instruments Corporation webpage at http://orin.com/index.htm
Qwerty Layout with integrated Dragger toolbar and Word Prediction.
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References1. 100 % Hands-free Computer Access – Madentec’s 2000 series, R. Marsden, P.Eng., Madentec
Limited, available at http://www.madentec.com/products/comaccess/2000/whitepaper.html
2. Review of Virtual Environment Interface Technology, C. Youngblut, R.E. Johnson, et al., Institute for Defence Analyses, available at http://www.hitl.washington.edu/scivw/scivw-ftp/publications/IDA-pdf/
3. Eye Control Technologies, Inc. webpage at http://www.naturalpoint.com
4. Hands-free navigation in VR environments by teacking the head, S.B. Kang, CRL 97/1Technical Report Series, available at http://www.hpl.hp.com/techreports/Compaq-DEC/CRL-97-1.pdf
5. A Head Operated Joystick – Experience with use, G. Evans and P. Blenkhorn, CSUN 99, available at http://www.csun.edu/cod/conf/1999/proceedings/session0019.htm
6. Origin Instruments Corporation webpage at http://orin.com/index.htm
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THE END