Scanner

Scanners are devices that are used to convert phyical image media into digital image data (organising).

Process
Scanners work via light sensitive cells that convert light to electricity in the scanner. A ‘head’ containing these cells moves down the page. Light from a lamp coming from behind the scanner shines upon the object, the cells measure the light coming back. They scan for the primary colours-blue, green and red, recording it as an image. A system called an OCR (Optical Character Recognition) then ‘reads’ the image and identifies the text or numbers. The information is converted into binary code and sent to the computer.

The resolution of the image is determined by the brightness of the lamp behind the cells, and the quality of the lenses that reflect the image. To increase the pixels per square centimetre the software adds a pixel in-between the original pixels and figures out the colour the pixel it should be.

Some companies offer scanners the with 30 or 36 bit colour meaning the scanner is able to produce more colours per pixel. The normal scanner only create one colour using 24 bites.

To send all this information to the computer, the scanner can use one of four different methods. The first way is to use a parallel port however, its popularity is decreasing because this method is very slow. The second way is via a SCSI (Small Computer System Interface). This uses a special SCSI card. Another way is using a USB. The last and fastest method, commonly used to download high resolution images is called FireWire.