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

1

Interaction Devices:Input Devices

Lecture 11Date: 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 IntroductionAn early input/output device: ASR33 An early input/output device: ASR33

teletype :teletype :

4

Interaction Device Introduction

window 1

window 2

12-37pm

• 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


•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


•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


InteractionInteractionDevicesDevices

InputInputDevicesDevices

OutputOutputDevicesDevices

8

Input Devices

• An input deviceinput 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

Text-Entry Devices

• 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

11

Keyboards

Keyboards Types:

• QWERTY

• Alphabetic

• Chord

• Dvorak

• Braille

• Mobile Phone Keyboard

Text-Entry Devices

12

QWERTY Keyboards

Text-Entry Devices

2 3 4 5 6 7 8 9 0

Q W E R T Y U I

1

O P

S D F H J LA G K

Z X C V B N M , .

SPACE

•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

13

Alphabetic Keyboards

Text-Entry Devices

•Keys arranged in alphabetic order

•not faster for trained typists

•not faster for beginners either

•No inherent advantage

•Sometimes used in personal organisers

14

Chord Keyboards

Text-Entry Devices

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

15

Dvorak Keyboards

Text-Entry Devices

•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

16

Braille Keyboards

Text-Entry Devices

• Keyboard especially adapted to blind or visually impaired users

• Keys are embossed to enable identification of keys

• Frequently used with “voice output” systems

17

Mobile Phone Keyboards

Text-Entry Devices

• 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’

18

Other Text Entry Devices

Handwriting recognitionHandwriting 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

Text-Entry Devices

•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

20

Speech Recognition

Text-Entry Devices

Primary components of a speech recognition system:Primary components of a speech recognition system:

1. Speech capture device = Microphone and associated analog-to-digital converter that digitally encodes the speech waveform

2. Digital signal processing module – detects word boundaries and separates useful speech information other unimportant data

3. Specialised speech recognition software, incorporating reference speech patterns, and pattern matching algorithms

21

Speech Recognition

Text-Entry Devices

Speech Speech recognitionrecognition systems can be categorised by systems can be categorised by number of users: 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

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.

23


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.


24


• 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


25

Positioning & Pointing DevicesGeneral DevicesGeneral DevicesIndirect pointing device

• Mouse• Trackball• Joystick• Touchpad

Direct control pointing device• Touch-Sensitive screens• Light Pen

Devices for the DisabledDevices for the Disabled• Eyegaze device• Eye Typer• Head movement tracker


26


Indirect Pointing Devices – MouseIndirect 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


27


Indirect Pointing Devices – TrackballIndirect 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


28


Indirect Pointing Devices – JoystickIndirect Pointing Devices – Joystick

• Usually used for tasks incorporating direction and speed rather than location

• Compact - requires very little space• Compact, must be stable• Absolute (movement) and isometric (direction

and velocity)• Inexpensive and robust• Often found in computer games


29


Indirect Pointing Devices – TouchpadIndirect 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


30


Direct Control Pointing Devices – Touch Direct Control Pointing Devices – Touch Sensitive ScreensSensitive 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


31


Direct Control Pointing Devices – Light PensDirect 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


32


Devices for Disabled – EyeGaze DeviceDevices 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


33


Devices for Disabled – Eye Typer DeviceDevices 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.


34


Devices for Disabled – Head Movement Devices for Disabled – Head Movement TrackerTracker

• 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


35

Other Device Types

• Picture Entry devices• Scanners• Video cameras• MPEG camera

• Sound entry devices• Microphone


36

Summary of Lecture

References

•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

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

Documents

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