CAMBRIDGE COMPUTER SCIENCE

1. INPUT AND
OUTPUT
DEVICES
Chapter 5

2. INPUT AND OUTPUT DEVICES
The input devices we will cover include:
• scanners
• barcode readers/scanners
• quick response (QR) code readers
• digital cameras
• keyboards
• pointing devices (such as a mouse)
• microphones
• touchscreens
• sensors
• interactive whiteboards.

3. SCANNERS
A scanner is a device that captures images from
photographic prints, posters, magazine pages, and similar
sources for computer editing and display. ... Very high
resolution scanners are used for scanning for high-
resolution printing, but lower resolution scanners are
adequate for capturing images for computer display.
SCANNERS are either
TWO-DIMENSIONAL (2D) OR THREE-DIMENSIONAL
(3D).

4. TWO-DIMENSIONAL SCANNERS
These types of scanner are the most common form and are generally used to input
hard-copy (paper) documents. The image is converted into an electronic form which
can be stored in a computer.
Figure 5.1 A number of stages occur when scanning a document (study them
from text book page 82 )
Computers equipped with OPTICAL CHARACTER RECOGNITION (OCR) software
allow the scanned text from the document to be converted into a TEXT FILE FORMAT.
This means the scanned image can now be edited and manipulated by importing it into
a word processor.

5. OPTICAL CHARACTER READER (OCR)
• Optical character recognition or optical character reader (OCR) is the electronic
or mechanical conversion of images of typed, handwritten or printed text into
machine-encoded text, whether from a scanned document, a photo of a
document, a scene-photo (for example the text on signs and billboards in a
landscape photo) or from subtitle text superimposed on an image (for example:
from a television broadcast).[
• Widely used as a form of data entry from printed paper data records – whether
passport documents, invoices, bank statements, computerized receipts,
business cards, mail, printouts of static-data, or any suitable documentation
• It is a common method of digitizing printed texts so that they can be
electronically edited, searched, stored more compactly, displayed on-line, and
used in machine processes such as cognitive computing, machine translation,
(extracted) text-to-speech, key data and text mining. OCR is a field of research
in pattern recognition, artificial intelligence and computer vision
See the link below
• https://www.google.com/search?q=ocr+scanner&client=firefox-b-
d&hl=en&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjAwOK-
v4vqAhXD5KQKHcQKAB4Q_AUoAXoECA0QAw&biw=1366&bih=664#imgrc=E2
NfdAfpNy190M

6. APPLICATIONS
OF
2D SCANNER
• 2D scanners are usually used to make digital copies of
documents or pictures, but can also be used to create a
2D image of other objects as well. In a flat bed scanner
the document is placed on a glass plate. A light is then
shone on the piece of paper and a light sensor used to
detect the light which is bounced back.
Watch the video regarding 2d scanners
• https://www.youtube.com/watch?v=DxCGJY_4DjE