CHAPTER 9CHAPTER 9

INTERACTION DEVICES

Ben Carson

Rajesh Golla

Sunil Dsouza

IntroductionIntroduction

Advances have yielded more productivity

Future input devices will involve more of

the body: gestures, voice, wearable devices

Advances in computing power have led to advances in input and output devices

Keyboards and Function KeysKeyboards and Function Keys

Different types of keyboard, depending on function used for

Several Key Layouts Keyboard Keys Functions Keys Cursor Movement Keys

Pointing DevicesPointing Devices

Select Position Orient Path Quantify Text

Tasks

Direct Control pointing Direct Control pointing devicesdevices

Lightpen Touchscreen Stylus

Examples Advantages Direct control Easier to learn than

indirect control

Disadvantages

Obscures Screen Arm fatigue

Smudging of display (touchscreen)

Removal of hand from keyboard

Indirect Control pointing Indirect Control pointing devicesdevices

ExamplesMouseTrackballJoystickTrackpointGraphics tabletTouchpad

Advantages Doesn’t obscures screen Less arm fatigue No smudging

Disadvantages Removal of hand from

keyboard Indirect control harder to

learn than direct control

Comparision of pointing Comparision of pointing devicesdevices

Best pointing devices depends on the taskTablet: long periods of being away from keyboard touchscreen/trackball: public access, shop floor,

laboratory applicationsMouse/trackball/tablet/touchpad: pixel-level

pointingKeyboard Cursor keys: moving between a small

number of targetsJoystick/trackball: game and flight sim designers

FITT’S LAWFITT’S LAW Developed by Paul Fitts in 1954

Index of difficulty=log2(2D/W)

Time to Point=C1 + C2(Index of Difficulty)

Sears and ShneidermanTime for precision pointing=

C1+C2(Index of Difficulty)+C3 log2(C4/W)

Novel pointing devicesNovel pointing devices

Foot Mouse Eye-tracking, gaze detection DataGlove Binocular Omni-Orientation Monitor (BOOM) Several variants of 3-D pointing devices Haptic feedback

Speech generation,Digitization and Speech generation,Digitization and recognitionrecognition

Voice commanding : more demanding of users working memory

Background noise Variations in user speech

Very useful for handicapped people

Speech technology

Discrete word recognition Continuous speech recognition Speech store and forward Speech generation

All of them can be combined in creative ways

Discrete Word RecognitionDiscrete Word Recognition

The devices recognize individual words spoken by specific person

Reliability: 90 to 98 percent for 20-200 word vocabulary

Speaker dependent training Speaker independent training Careful choice of employees improves

recognition rates

Applications

Physically handicapped Speakers hands are busy Mobility is required Speakers eyes are occupied

Examples: Aircraft engine inspectors, baggage handlers

Studies show that speech input was not found to be beneficial

Continuous Speech RecognitionContinuous Speech Recognition

Commercially successfully products are restricted to specialty niches such as radiologists

Difficulty is recognizing the boundaries between spoken words

AIM: dictate letters, compose reports verbally, scan long audio tracks, identifications purposes

ProductsProducts

Verbex: 99.5 percent accuracy, speaker dependent training, vocabulary up to 10000 words

Speech systems: 95 percent accuracy, speaker independent training, 40000 word vocabulary

Target tasks: operating system control, police requests for info on car license, stock broker orders

Speech Store and ForwardSpeech Store and Forward

Less exciting- more useful Commonly used for weather, airline, financial

information, personal messaging telephone Voice mail technology Telephone based information systems Personal tape recorders Audio tours in museums

Speech GenerationSpeech GenerationReliable speech generation devices used in

Cameras Soft drink vending machines Automobiles Games

Applications for the blind

Speech generation preferred when

Message is short Message is simple Message will not be referred to later Message deals with events in time Message requires immediate response Visual channels of communications are overloaded Environments unsuitable for visual information User must be free to move around User is subject to high G forces

Other machine outputsOther machine outputs

Audio tones Audiolization Music

Used to give feedback to the used

Warnings or acknowledgements Very helpful for blind users

Image and Video DisplaysImage and Video Displays Features

Rapid Operation

Reasonable size

Reasonable resolution

Quiet Operation

No paper waste

Low Cost

Reliability

Graphics and animation

Display DevicesDisplay Devices

Cathode Ray Tube

Liquid Crystal Displays

Plasma Panel

Light emitting Diodes

Digital Photography and Digital Photography and ScannersScanners

Digi cams Digital storage of photographs Electronic editing and manipulation

Scanners Convert maps,documents and manuscripts into

digital format Optical Character Recognition – convert text in

printed docs to electronic forms

Digital VideoDigital Video

Videodisks 12 inch 54000 still images/30 min video CD-ROMs 600+ mb of data 1 hour videos (depending on codec)DVD’s 2-3 hours of video storage

CODEC’s

Motion Picture Experts Group (MPEG)

RealVideo

H263 - medium-quality videoconferencing

Other DisplaysOther Displays

Projectors 2 by 3 meter displays Good saturation, small loss of fidelity

Heads-up displays video/data on partially silvered windscreen

Helmet Mounted Displays

PrintersPrintersNecessary Features Speed Print Quality Cost Compactness Quite operation Font,character set,size Reliability

SummarySummary

Devices which are cost effective Selecting rather than typing devices Better speech input devices Better video o/p devices.. Higher resolution,

color and larger displays

DESIGN