Interaction Devices: Input Devices

1. Interaction Devices:Input Devices Lecture 11 Date: 9th March

2. Overview of Lecture • General introduction to input/output devices • Input Devices • Text entry devices • Keyboards • Handwriting Recognition • Speech Recognition • Positioning and pointing devices • Direct control devices • Indirect control devices • Devices for disabled • Output Devices

3. Interaction Device Introduction An early input/output device: ASR33 teletype :

4. Interaction Device Introduction • Screen, or monitor, on which there are windows • Keyboard • Mouse/trackpad • Variations • desktop • laptop • PDA • The devices dictate the styles of interaction that the system supports • If we use different devices, then the interface will support a different style of interaction

5. Interaction Device Introduction • Cannot separate interface function from I/O interaction devices. • Majority of current interfaces designed to operate with keyboard and mouse. • New interaction styles and devices are required to support inputs such as voice input, gesture recognition, 3-D pointing, haptic interaction, wearable computers.

6. Interaction Device Introduction • Devices should be easy and pleasant to use, fast to learn, with minimal effort and error. They generally involve physical actions of dragging, clicking, typing, speaking, writing, etc. • Different devices have different affordances, and differing capacity for accuracy and feedback. • Also need to consider issues such as fatigue and long term health effects.

7. Interaction Device Introduction Interaction Devices Input Devices Output Devices

8. Input Devices • An input device is a device that, together with appropriate software, transforms information from the user into data that a computer application can process • Input devices can be categorised into • Text entry devices • Positioning and pointing devices • Devices that input pictures • Devices that input Sound

9. Text-Entry Devices • Keyboards • Other text-entry devices Text-Entry Devices

10. Keyboards • Most common input method • Discrete entry device (I.e. involves sensing one of two or more positions) • Physical design of keys and key groupings should be considered • A key-press closes a connection, causing a character code to be sent to the computer • Connection is usually via a lead, but can be wireless Text-Entry Devices

11. Keyboards Keyboards Types: • QWERTY • Alphabetic • Chord • Dvorak • Braille • Mobile Phone Keyboard Text-Entry Devices

12. QWERTY Keyboards • Named from topmost left letters • Most common keyboard • Based on typewriter key layout design – designed to prevent jamming of the keys • Not optimal for typing – frequently used letters placed far apart thereby increasing finger travel distances • Cost of replacement perpetuates use Text-Entry Devices

13. Alphabetic Keyboards • Keys arranged in alphabetic order • not faster for trained typists • not faster for beginners either • No inherent advantage • Sometimes used in personal organisers Text-Entry Devices

14. Chord Keyboards • Only a few keys - four or 5 • Letters typed as combination of key-presses • Compact size - ideal for portable applications • One handed use • Short learning time • Fast • But fatigue after extended use • Sample use – transcript recording in court Text-Entry Devices

15. Dvorak Keyboards • common letters under dominant fingers • biased towards right hand • common combinations of letters alternate between hands • 10-15% improvement in speed and reduction in fatigue • But - large social base of QWERTY typists produce market pressures not to change Text-Entry Devices

16. Braille Keyboards • Keyboard especially adapted to blind or visually impaired users • Keys are embossed to enable identification of keys • Frequently used with “voice output” systems Text-Entry Devices

17. Mobile Phone Keyboards • use numeric keys withmultiple presses • 2 – a b c 6 - m n o • 3 - d e f 7 - p q r s • 4 - g h i 8 - t u v • 5 - j k l 9 - w x y z • hello = 4433555[pause]555666 • surprisingly fast! • T9 predictive entry • type as if single key for each letter • use dictionary to ‘guess’ the right word • hello = 43556 … • but 26 -> menu ‘am’ or ‘an’ Text-Entry Devices

18. Other Text Entry Devices Handwriting recognition • Handwritten text is input into the computer, using a special pen and typically, a small notebook sized computer with a screen that the user can write directly onto. • Attractive as a text entry method because handwriting is a common familiar activity • Handwriting recognition software translates handwritten characters into ASCII text that can be displayed instantly on screen as printed characters • Handheld organizers – Apple Newton (the first), Psion, Palm, PocketPC (from Microsoft) Text-Entry Devices

19. Speech Recognition • Speech recognition technology replaces a computer keyboard with a microphone and software to change the spoken word into typed characters • Natural form of communication, easier to train new users than other input devices • Does not require hands or other limbs – operators can carry out other actions • Offers disabled people (particularly blind, motor impairment) the opportunities to use new technology • Limited by recognition error rate of speech recognition systems • Variety of accents and intonations increase error rate • External noise interfering Text-Entry Devices

20. Speech Recognition • Primary components of a speech recognition system: • Speech capture device = Microphone and associated analog-to-digital converter that digitally encodes the speech waveform • Digital signal processing module – detects word boundaries and separates useful speech information other unimportant data • Specialised speech recognition software, incorporating reference speech patterns, and pattern matchingalgorithms Text-Entry Devices

21. Speech Recognition • Speech recognition systems can be categorised by number of users: • Speaker-dependent system require each user to train a system to recognise their voice • Speaker-independent systems try to accommodate a large range of speaking characteristics and vocabulary Text-Entry Devices

22. Positioning & Pointing Devices Pointing devices are applicable in six types of interaction tasks: 1. Select: • user chooses from a set of items. • used for traditional menu selection, identification of a file in a directory, or marking of a part in an automobile design. 2. Position: • user chooses a point in a one-, two-, three-, or higher-dimensional space • used to create a drawing, to place a new window, or to drag a block of text in a figure. 3. Orient: • user chooses a direction in a two-, three-, or higher-dimensional space. • direction may simply rotate a symbol on the screen, indicate a direction of motion for a space ship, or control the operation of a robot arm. Positioning & Pointing Devices

23. Positioning & Pointing Devices 4. Path: • user rapidly performs a series of position and orient operations. • may be realized as a curving line in a drawing program, the instructions for a cloth cutting machine, or the route on a map. 5. Quantify: • user specifies a numeric value. • usually a one-dimensional selection of integer or real values to set parameters, such as the page number in a document, the velocity of a ship, or the amplitude of a sound. • 6. Text: • user enters, moves, and edits text in a two-dimensional space. The • pointing device indicates the location of an insertion, deletion, or change. • more elaborate tasks, such as centering; margin setting; font sizes; highlighting, such as boldface or underscore; and page layout. Positioning & Pointing Devices

24. Positioning & Pointing Devices • Pointing devices are generally fast and easy to use, but require hand-eye coordination. • Can be divided into: • direct control devices • indirect control devices • devices for disabled Positioning & Pointing Devices

25. Positioning & Pointing Devices General Devices Indirect pointing device • Mouse • Trackball • Joystick • Touchpad Direct control pointing device • Touch-Sensitive screens • Light Pen Devices for the Disabled • Eyegaze device • Eye Typer • Head movement tracker Positioning & Pointing Devices

26. Positioning & Pointing Devices Indirect Pointing Devices – Mouse • Requires physical space for movement • Provides relative motion • Can be difficult for novice users (indirect mapping) • Two characteristics: planar movement, and buttons Positioning & Pointing Devices

27. Positioning & Pointing Devices Indirect Pointing Devices – Trackball • Weighted ball is rotated inside a static housing • Compact -> Good for limited space situations – e.g. laptops • Difficult for long movements • Requires separate buttons for select Positioning & Pointing Devices

28. Positioning & Pointing Devices Indirect Pointing Devices – Joystick • Usually used for tasks incorporating direction and speed rather thanlocation • Compact - requires very little space • Compact, must be stable • Absolute (movement) and isometric (direction and velocity) • Inexpensive and robust • Often found in computer games Positioning & Pointing Devices

29. Positioning & Pointing Devices Indirect Pointing Devices – Touchpad • Typically used in portable computers to replace mouse • + requires minimal space (typically 2-3 inches in size • - can be difficult and inaccurate to use Positioning & Pointing Devices

30. Positioning & Pointing Devices Direct Control Pointing Devices – Touch Sensitive Screens • allows direct control touches on the screen using a finger • lift-off strategy enables users to point at a single pixel • the users touch the surface • then see a cursor that they can drag around on the display • when the users are satisfied with the position, they lift their fingers off the display to activate • can produce varied displays to suit the task • are fabricated integrally with display surfaces Positioning & Pointing Devices

31. Positioning & Pointing Devices Direct Control Pointing Devices – Light Pens • enabled users to point to a spot on a screen and to perform a select, position, or other task • it allows direct control by pointing to a spot on the display • incorporates a button for the user to press when the cursor is resting on the desired spot on the screen • Disadvantages: • users' hands obscured part of the screen, • users had to remove their hands from the keyboard, • users had to pick up the lightpen Positioning & Pointing Devices

32. Positioning & Pointing Devices Devices for Disabled – EyeGaze Device • An eyegaze unit is worn on a headband on the users head - screen cursor is driven by users eye movements • + good for disabled users with motor impairments or any environment where user is limited in movement +Fast +accurate - Expensive - Good for selection, but not for continuous movement of cursor Positioning & Pointing Devices

33. Positioning & Pointing Devices Devices for Disabled – Eye Typer Device • Developed for users with severe motor impairment • The user “types” by scanning the keyboard and fixing momentarily on each character that is wanted • The characters are displayed on a panel in qwerty keyboard layout. Each character has a light embedded in it. The display has a camera that can detect which character the user is looking at. Positioning & Pointing Devices

34. Positioning & Pointing Devices Devices for Disabled – Head Movement Tracker • Developed for users with severe motor impairment • The user wears a lightweight headset. The “keyboard” is a display on the screen. The system detects slight movements of the user’s head to move cursor. To operate a key, user moves cursor to the key and blows on a blow switch Positioning & Pointing Devices

35. Other Device Types • Picture Entry devices • Scanners • Video cameras • MPEG camera • Sound entry devices • Microphone Positioning & Pointing Devices

36. Summary of Lecture • Input Devices • Text entry devices • Keyboards – QWERTY, Alphabetic, Chord, Dvorak, Braille • Handwriting Recognition • Speech Recognition • Positioning and pointing devices • Direct control devices • Mouse • Trackball • Joystick • Touchpad • Indirect control devices • Touch-Sensitive screens • Light Pen • Devices for disabled - Eyegaze device, Eye Typer, Head movement tracker References

37. Terms of Reference • Shneiderman, B. & Plaisant, C. (2005) Designing the User Interface • Preece, J. et al. (2002) Interaction Design • Benyon, D. et al (2005) Designing Interactive Systems • Helander, M. et al (1997) Handbook of Human-Computer Interaction • Norman, D. (1990) The Design of Everyday Things References