Lecture 4 by coooolone

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									INTRODUCTION TO COMPUTER                                              LECTURE 04


ALTERNATIVE METHODS OF INPUT
        Although the keyboard and mouse are input devices with which people
work most often on the desktop there a number of other ways to get data into a
computer.
iii)    PENS
        Pen base system uses an electronic pen as their primary input device. You
hold the pen in your hand and write on a special pad or directly on the serene.
You can also use the pen as a pointing device, like a mouse, to select commands.
It is important to realize that the screen is the input device, not the pen. The
screen detects pressure, light, or an electrostatic change that comes from the pen
and then stores the position of that signal.
iv)     TOUCH SCREEN
Touch screens allows the user to point directly at the computer display usually to
select from a menu of choices on the screen. Most touch screen computers use
sensors in, or near, the computer screen that can detect the touch of a finger
sensing either the finger pressure or warmth.
v)      IMAGE SCANNERS
        Image scanner convert any image into electronic form by shining light on
to the image and sensing the intensity of the reflection at every point.
Color or scanners use fitters to separate colors (red, green & blue) at each point
and they are combined to create any other color.


Printed page                                                        (1) Alight source
Light Source                                                          moved across
                                                                      A printed page
                                                                    (2) the light
Lens                                                                 bounces off the
                                                                     Page and its
                                                                     Passes through a
                                                                     lens
Light Sensitive                                                      (3) On to light
diode                                                  sensitive     diodes,
                                                                     which convent
                                                                    the light to
                                                                     electrically. There
                                                                     are usually 300 or
Circuit board                                                       600 diodes per ch.
                                                                    (4) A circuit board
                                                                   converts the electric-
                                                                    city to number and
                                                                      sends information
                                                                        to computer.




PREPARED BY SADIQ A.BUGTI LECTURER BUITMS                                               1
INTRODUCTION TO COMPUTER                                         LECTURE 04

vi)    MICROPHONES AND VOICE RECOGNITION
       Now that sound capabilities are a standard part of computers,
microphones are becoming increasingly in multimedia, where presentation can
benefit from narration, music or sound effects.
A sound card that translates the electrical signal from the microphone into
digitized form that computer can store and process. Sound card can also
translate digitized sounds back into analog signals that can be sent to the
speakers.
vii)   VIDEO INPUT
With the growth of multimedia and the internet, computer to their system are
adding video input capabilities to their system in great numbers. Applications
such as video conferencing enable user to useful motion video images, captured
by a PC video camera, and transmit them to a limited number of recipients on a
network or to the world on to the internet.
viii) DIGITAL CAMERAS
Digital cameras work in much the same way as PC video cameras, expect digital
cameras, and are portable, handheld device that captured still images. Whereas
normal film cameras capture images on a special coated film, digital cameras
capture images electronically. To do this digital cameras digitizes the image
compresses it and stores it on a special disk or ROM card. The user can then copy
the information on to a PC s, where the image can be edited, copied, printed,
embedded in a document or transmitted to another user.




PREPARED BY SADIQ A.BUGTI LECTURER BUITMS                                      2

								
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