PxS’12 - week 8 - mobile i/o


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PxS’12 - week 8 - mobile i/o

  1. 1. EPFL, spring 2012 – week 8!mobile i/o
  2. 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. 3. handhelds: three broad categories
  4. 4. why touchscreens?➝  larger screens for video, maps, websites, documents etc➝  easier to point
  5. 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. 6. design challenge: screen space
  7. 7. design challenge: context
  8. 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. 9. Text entry research timeline Mackenzie 2008
  10. 10. three broad categories Physical Virtual Keyboards key-based finger-based stylus-based
  11. 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. 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. 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. 14. number of keys continuummore ambiguity continuum less
  15. 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. 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. 17. virtual keyboards: feedback➝  performance with virtual keyboards improves with vibro- tactile feedback➝  visual and audio feedback may also be useful
  18. 18. ➝  finger/thumb occludes➝  lower precision when pointing
  19. 19. offset cursor
  20. 20. “shift” target selection technique➝  “shift” – a technique for enabling fine cursor pointing using fingers
  21. 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. 22. behind touch
  23. 23. pseudo transparency
  24. 24. tilting (Rekimoto uist 96)
  25. 25. “chameleon” (Fitzmaurice 1993)
  26. 26. peephole display (Yee 2003)
  27. 27. camera phone based motion sensing (Whang, Zhai & Canny 2006)
  28. 28. viewing large documents on small displays
  29. 29. overviews (O’Hara et al 1999) (Woobrock et al 2002)
  30. 30. off-screen visualizations: edge radar
  31. 31. off-screen visualizations (Baudisch & Rosenholtz 2003 Gustafson et al 2008)
  32. 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. 33. why use audio and/or haptic output? ➝  attention grabbing ➝  saves screen real estate ➝  can provide information without requiring visual attention
  34. 34. earpod
  35. 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. 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