Lecture 11 InputDev

8/14/2019 Lecture 11 InputDev

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Interaction Devices:

Input DevicesLecture 11

Date: 9th March



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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



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Interaction Device Introduction

An early input/output device: ASR33 teletype : An early input/output device: ASR33 teletype :



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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 differentstyle of interaction



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•Cannot separate interface function from I/Ointeraction devices.

•Majority of current interfaces designed tooperate 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.



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•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.




InteractionInteraction

DevicesDevices

InputInput

DevicesDevices

OutputOutput

DevicesDevices



Input Devices

• An input deviceinput device is a device that, together withappropriate 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



Text-Entry Devices

• Keyboards

• Other text-entry devices

Text-Entry Devices



Keyboards

Text-Entry Devices

• Most common input method

• Discrete entry device (I.e. involves sensing one of two or morepositions)

• Physical design of keys and key groupings should be considered

• A key-press closes a connection, causing a character code to besent to the computer

• Connection is usually via a lead, but can be wireless



Keyboards

Keyboards Types:

• QWERTY

• Alphabetic

• Chord

• Dvorak

• Braille

• Mobile Phone Keyboard

Text-Entry Devices



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



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



Chord Keyboards

Text-Entry Devices

Only a few keys - four or 5

•Letters typed as combination of key-presses

•Compact size - ideal for portableapplications

•One handed use

•Short learning time•Fast

•But fatigue after extended use

•Sample use – transcript recording in court



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



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



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’



Other Text Entry Devices

Handwriting recognitionHandwriting recognition

• Handwritten text is input into the computer, using a specialpen and typically, a small notebook sized computer with ascreen that the user can write directly onto.

• Attractive as a text entry method because handwriting is a

common familiar activity

• Handwriting recognition software translates handwrittencharacters into ASCII text that can be displayed instantly onscreen as printed characters

• Handheld organizers – Apple Newton (the first), Psion, Palm,PocketPC (from Microsoft)

Text-Entry Devices



Speech Recognition

Text-Entry Devices

•Speech recognition technology replaces a computer

keyboard with a microphone and software to change thespoken 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 cancarry out other actions

•Offers disabled people (particularly blind, motor

impairment) the opportunities to use new technology

•Limited by recognition error rate of speech recognitionsystems

•Variety of accents and intonations increase error rate

•External noise interfering



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 wordboundaries and separates useful speech information other

unimportant data

3. Specialised speech recognition software, incorporating

reference speech patterns, and pattern matching algorithms



Speech Recognition

Text-Entry Devices

SpeechSpeech recognitionrecognition systems can be categorised bysystems can be categorised bynumber 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



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.




4. Path:

•user rapidly performs a series of position and orient operations.

•may be realized as a curving line in a drawing program, the instructionsfor 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 setparameters, such as the page number in a document, the velocity of aship, 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.


P i i i P i i D i




• Pointing devices are generally fast andeasy to use, but require hand-eye

coordination.

• Can be divided into:

• direct control devices

• indirect control devices

• devices for disabled


P i i i P i i D i



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General DevicesGeneral Devices

Indirect 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


P i i i P i i D i



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Indirect Pointing Devices – MouseIndirect Pointing Devices – Mouse

• Requires physical space for movement

• Provides relative motion

• Can be difficult for novice users (indirectmapping)

• Two characteristics: planar movement, and

buttons


P i i i P i i D i



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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


P iti i P i ti D i



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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


P iti i P i ti D i



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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


P iti i P i ti D i



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Direct Control Pointing Devices – TouchDirect Control Pointing Devices – Touch

Sensitive ScreensSensitive Screens

• allows direct control touches on the screen usinga finger

• lift-off strategy enables users to point at a singlepixel

• the users touch the surface

• then see a cursor that they can drag around onthe 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


P iti i & P i ti D i



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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 whenthe 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 De ices



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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





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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 eachcharacter 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.





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Devices for Disabled – Head Movement Tracker 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


Other Device Types



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Other Device Types

• Picture Entry devices• Scanners

• Video cameras

• MPEG camera

• Sound entry devices

• Microphone


S f L t



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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 movementtracker



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

Documents

Lecture 11 InputDev