8. Scanner

Scanners can be used to convert images or text on paper into a digital format that can be used by the computer.

scannerA scanner works by shining a beam of light onto the surface of the object that you are scanning. This light is then reflected back onto a sensor that detects the colour of the light. This is then used to build up the digital image.

Items that are scanned are usually stored in an image format. However, special software - Optical Character Recognition - can be used to convert text on the paper into text which can be edited with a word processor. However, the text doesn't always get converted very well and you could end up with a lot of mistakes.

There are two types of scanner:

  • Flatbed scanners
  • Handheld scanners

The most popular type is the flatbed scanner. This is probably the one that you use at school. They can scan larger images and are more accurate than handheld scanners.

Handheld scanners are usually only a few inches wide and are held in the hand whilst they are rolled across the document to be scanned. The images produced are generally not as large or as high quality as those captured with a flatbed scanner.

 

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Advantages
  • Flatbed scanners are very accurate and can produce reasonably high quality images
  • Any image which is digitised by the scanner can then be included on electronic documents
  • Images once digitised can be enhanced with a graphics application
Disadvantages
  • Images can take up a lot of memory space
  • Images lose some quality in the scanning and digitising process
  • The quality of the final image is dependent on the quality of the original image
 

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