PxS’12 - week 8 - mobile i/o

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  • 1. EPFL, spring 2012 – week 8!mobile i/o
  • 2. overview➝  types of mobile device➝  design challenges ➝  in: text entry➝  in: overcoming finger occlusion➝  in: movement➝  out: overviews➝  out: off-screen visualizations➝  out: audio & haptic output ✱this lecture is based on Will Seager s (UCL) lecture of mobile systems
  • 3. handhelds: three broad categories
  • 4. why touchscreens?➝  larger screens for video, maps, websites, documents etc➝  easier to point
  • 5. finger vs stylusadvantages of finger…➝  can’t lose stylus➝  fast response to alerts e.g. phone calls➝  one-handed operationdisadvantages…➝  low pointing accuracy➝  finger occlusion➝  dirty screen
  • 6. design challenge: screen space
  • 7. design challenge: context
  • 8. in: text entry ➝  > 1 billion text messages sent per day ➝  most common type of mobile interaction ➝  companies are looking for improvements to mobile text entry methods ➝  many methods currently exist
  • 9. Text entry research timeline Mackenzie 2008
  • 10. three broad categories Physical Virtual Keyboards key-based finger-based stylus-based
  • 11. physical vs virtual keyboards➝  physical keyboards ➝  mobile phone keypad, mobile qwerty (e.g. Blackberry), 5 button pager, 3-key date stamp, 1 key input etc➝  virtual keyboards ➝  aka “soft keyboards” or “on-screen keyboards” ➝  similar to clicking buttons in a GUI ➝  used with a stylus or a finger (but also with other input mechanisms e.g. eye tracking)➝  design issues ➝  number of keys, key layout, key size, key shape, activation force, feedback, disambiguation, language modelling, word prediction etc
  • 12. number of keys & layout QWERTY➝  both physical & virtual keyboards vary in number of keys & layouts➝  for mobile text input, 26 MOBILE key qwerty & 9/12 key ABC are by far the most common➝  other 26-key layout variations include Opti, Dvorak & Fitaly ➝  other 9/12 key variations include 9/12 key qwerty
  • 13. number of keys & layout QWERTY➝ other layouts have been shown to lead to better performance BUT familiarity a crucial OPTI factor opti outperforms qwerty (faster, fewer errors) after a few hours practice
  • 14. number of keys continuummore ambiguity continuum less
  • 15. ambiguity 7 8 6 6 3 7 ? PQRS TUV MNO MNO DEF PQRS or, is it SUMMER, is it STONES ?➝  ambiguity occurs if there are fewer keys than symbols in the language => disambiguation is needed to select the intended word from the possibilities.➝  disambiguation methods include multi-tap and T9
  • 16. virtual keyboards stylus methods SWYPE ➝  tapping on virtual keyboards ➝  handwriting recognition finger methods ➝  tapping on virtual keyboards new method for stylus & finger ➝  sliding stylus/finger across the screen
  • 17. virtual keyboards: feedback➝  performance with virtual keyboards improves with vibro- tactile feedback➝  visual and audio feedback may also be useful
  • 18. ➝  finger/thumb occludes➝  lower precision when pointing
  • 19. offset cursor
  • 20. “shift” target selection technique➝  “shift” – a technique for enabling fine cursor pointing using fingers
  • 21. “escape” target selection technique a)  the user presses his/her thumb near the desired target b)  the gestures in the direction indicated by the target c)  the target is selected, despite several nearby distractors.
  • 22. behind touch
  • 23. pseudo transparency
  • 24. tilting (Rekimoto uist 96)
  • 25. “chameleon” (Fitzmaurice 1993)
  • 26. peephole display (Yee 2003)
  • 27. camera phone based motion sensing (Whang, Zhai & Canny 2006)
  • 28. viewing large documents on small displays
  • 29. overviews (O’Hara et al 1999) (Woobrock et al 2002)
  • 30. off-screen visualizations: edge radar
  • 31. off-screen visualizations (Baudisch & Rosenholtz 2003 Gustafson et al 2008)
  • 32. audio & haptic output➝  non speech audio output ➝  bleeps, earcons, auditory icons➝  haptics ➝  refers to interaction via sense of touch Example earcons from (Brewster et al 2008) and/or motor activity.
  • 33. why use audio and/or haptic output? ➝  attention grabbing ➝  saves screen real estate ➝  can provide information without requiring visual attention
  • 34. earpod
  • 35. head-mounted displays➝  user can look at environment & display at the same time➝  potentially good for location based and augmented reality servies as potential for clear link between information & the environmentbut…➝  require separate input device e.g. trackball or else speech only input
  • 36. summary: some key points➝  Key design challenges: small screens & context➝  mobile text entry research ongoing, in particular for finger-based input via touch screens➝  movement as input➝  importance of overviews when browsing documents on small screens➝  off-screen visualizations➝  audio & haptic output is a way to reduce demand on visual attention