CHAPTER 9 INTERACTION DEVICES Ben Carson Rajesh Golla Sunil Dsouza

Introduction  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 Keys  Different types of keyboard, depending on function used for  Several Key Layouts  Keyboard Keys  Functions Keys  Cursor Movement Keys

Pointing Devices  Select  Position  Orient  Path  Quantify  Text  Tasks

Direct Control pointing devices 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 devices  Examples  Mouse  Trackball  Joystick  Trackpoint  Graphics tablet  Touchpad  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 devices  Best pointing devices depends on the task  Tablet: long periods of being away from keyboard  touchscreen/trackball: public access, shop floor, laboratory applications  Mouse/trackball/tablet/touchpad: pixel-level pointing  Keyboard Cursor keys: moving between a small number of targets  Joystick/trackball: game and flight sim designers

FITT’S LAW  Developed by Paul Fitts in 1954  Index of difficulty=log 2 (2D/W)  Time to Point=C 1 + C 2 (Index of Difficulty)  Sears and Shneiderman  Time for precision pointing= C 1 +C 2 (Index of Difficulty)+C 3 log2(C 4 /W)

Novel 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 recognition Speech generation,Digitization and recognition 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 Recognition  The devices recognize individual words spoken by specific person  Reliability: 90 to 98 percent for 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 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

Products  Verbex: 99.5 percent accuracy, speaker dependent training, vocabulary up to words  Speech systems: 95 percent accuracy, speaker independent training, word vocabulary  Target tasks: operating system control, police requests for info on car license, stock broker orders

Speech 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 Generation Reliable 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 outputs  Audio tones  Audiolization  Music Used to give feedback to the used  Warnings or acknowledgements  Very helpful for blind users

Image and Video Displays  Features  Rapid Operation  Reasonable size  Reasonable resolution  Quiet Operation  No paper waste  Low Cost  Reliability  Graphics and animation

Display Devices  Cathode Ray Tube  Liquid Crystal Displays  Plasma Panel  Light emitting Diodes

Digital Photography and Scanners 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 Video Videodisks  12 inch  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 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

Printers Necessary Features  Speed  Print Quality  Cost  Compactness  Quite operation  Font,character set,size  Reliability

Summary  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