COMPUTER SCIENCEBASIC LECTURE Lecture_5.pptx

CSC 101
Introduction to Computing
Lecture 5
1

Ergonomics and Input Devices
 Ergonomics
 which is the study of the physical relationship between
people and their tools—such as computers— addresses
these issues.
 People recognize the importance of having
ergonomically correct computer furniture
 Ergonomically correct
 means that a tool or a workplace is designed to work
properly with the human body, and
 thus reduces the risk of strain and injuries.
2

Repetitive Strain Injury (RSI)
 an injury of the musculoskeletal and nervous
systems that may be caused by
 repetitive tasks,
 forceful exertions,
 vibrations,
 mechanical compression (pressing against hard
surfaces),
 sustained, or
 awkward positions
 Caused by continuous misuse of the body in ways
it was not designed to work
 Many professions suffer from RSI
3

4
Avoiding Keyboard Related Injuries

Techniques to Avoid RSI
 Use an ergonomic keyboard
 Sit up straight
 Have a padded wrist support
 Keep your arms straight
 Keyboard properly
 Take frequent breaks
7

Few Basics: Input Devices
 Mouse
 Keyboard
 Joystick
 Light pen
 Bar Code Reader
 Tablet
 Camera
 Microphone
9

Devices for the Hand - Pen
10
 Tablet PCs, PDA
 Pen used to
write data
 Pen used as
a pointer
 Handwriting
recognition is difficult
 On screen keyboard
 Not used for inputting
large volume of data

Touch Screens
 accept input by allowing
the user to place a
fingertip directly on the
computer screen
 Use sensors to detect
touch
 Well suited for simple
applications
 ATM
 Public information kiosk
11

Touch Screens
 work well in environments where dirt or weather
would render keyboards and pointing devices
useless, and
 where a simple, intuitive interface is important.
 Touch screens have become common in
 fast-food restaurants,
 department stores,
 drugstores, and supermarkets,
 where they are used for all kinds of purposes, from
creating personalized greeting cards to selling lottery
tickets.
12

Game Controllers
 Enhances gaming experience
 Provide custom input to the game
 Modern controllers offer feedback
 Two broad Categories
 Joystick
 Game pad
13

Joystick
 Around for long time
 Can be used other than games
 enable the user to “ fly” or “ drive” through a
game, directing a vehicle or character
 popular in racing and flying games
 One variant is the racing game controller, which
includes an actual steering wheel
 some racing game controllers even include foot
pedals and gearshifts
14

Game Pad
 is a small, flat device that usually provides two
sets of controls— one for each hand.
 extremely flexible and are used to control many
kinds of games
 If you do not have a joystick, you can use a
game pad to control most racing and flying
games.
 Many computer games still provide support for
a mouse or keyboard, so a dedicated game
controller is not always required
15

Optical Input Devices
16
 Allows the computer to see
input
 Bar code readers
 Converts bar codes to
numbers
 UPC Universal Product Code
 Computer find number in a
database
 Works by reflecting light
 Amount of reflected light
indicates number

Bar Code Reading Process
 reader emits a beam of that is reflected by the bar
code image
 light-sensitive detector identifies the bar code image
by recognizing special bars at both ends of the
image
 special bars are different, so the reader can tell
whether the bar code has been read right-side up or
upside down
 After detector has identified the bar code, it converts
the individual bar patterns into numeric digits code
the computer can understand
 reader then feeds the data into the computer
17

Image Scanners
 Converts printed media into electronic
 Reflects light on the image
 Sensors read the intensity
 Filters determine color depths
18

Color Scanners
 use filters to separate the components of color
into the primary additive colors (red, green, and
blue) at each point
 Red, Green, and Blue (RGB) are primary
additive colors because they can be combined
to create any other color
 The image scanner is useful because it
translates printed images into an electronic
format that can be stored in a computer’s
memory
19

Optical Character Recognition (OCR)
 Converts scanned image into editable text
 Image is stored in the computer’s memory as a
bitmap.
 Bitmap is a grid of dots, each dot represented
by one or more bits
 translate that array of dots into text that the
computer can interpret as letters and numbers
20

Optical Character Recognition (OCR)
 Each letter is scanned
 Letters are compared to known letters
 Best match is entered into document
 Rarely 100% accurate
21

Scanner types
22
 Handheld scanners
 more portable but typically
require multiple passes to scan a
single page
 Flatbed scanners
 offer higher-quality reproduction
than do handheld scanners and
 can scan a page in a single pass

Audiovisual Input Devices
 Microphones
 Used to record speech
 Speech recognition
 “Understands” human speech
 Allows dictation or control of computer
 Matches spoken sound to known phonemes
 Enters best match into document
23

Speech Recognition
 demand for translating spoken words into text
 Translating voice to text is a capability known
as speech recognition (or voice recognition).
 With it, you can dictate to the computer instead
of typing, and you can control the computer with
simple commands
 translates Phonemes into text or commands
24

Other type of Audio Input
 Computers can accept many kinds of audio
input
 Sound card with the appropriate plugs
 a compact disc
 a tape player
 a radio or
 even a record player
 If the audio source outputs sounds in the form
of analog, sound card must convert the analog
signals into digital code so the computer can
store and use it.
25

Video Input
 With growth of multimedia and the Internet,
computer users are adding video input
capabilities to their systems in great numbers
 Applications such as video conferencing enable
people to use full-motion video images
 Videos are commonly used in presentations
and on Web pages
26

Video Camera and Webcam
 video cameras used with computers digitize
images by breaking them into individual pixels
 pixel is one or more dots that express a portion
of an image
 Each pixel’s color and other characteristics are
stored as digital code
 With Webcam the user can “capture” images of
himself or herself while working at the computer
27

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