How Scanners Work

Recreating a whole document whose hard copy you have but not the soft copy is very boring and curb some, for this purpose the scanner were invented. And they proved very effective.

Put in a paper in a scanner, the light moves and the very next second you see the second you see the document on the connected computers screen. Puzzled how it happens. No it is not that confusing and sophisticated, rather it is a very simple process which is illustrated as below:

  • A scanner’s job is to turn a picture a human can understand into a digital picture that a computer can store and process. The computer is not able to use graphics unless they are in a form that they can understand. The scanner takes the information it sees on a page and converts into code that the computer can use.  They convert the image or the document into a myriad number of zeros and one, which is called the binary code.
  • And the scanner does this by moving the scanning head backwards and forwards across the picture. This is done to recreate the image, one line at a time, and then convert it into a digital language understandable by the computer. The computer further converts into a pictorial format or the document format, for the user to understand. This is the process of scanning, and in this way we call such devices as Scanners. A scanner’s sophistication is the ability to translate an unlimited number of analog voltage levels to digital values.
  • The main feature of the scanner is its resolution which is measured in dots per inch also known as Dpi. The higher the resolution, more the memory is required to save the document or the image on the computer. More memory required thus more time would be utilized to reproduce it on the screen and also to scan. Usually 72 dots per inch is the prescribed resolution, which is also the best to view any images or documents on screen.
  • There are three types of scanner namely flatbed, sheet bed and hand held scanners. They are named so according to the manner of their scanning. The sheet bed scanner employs mechanical rollers that move the paper past the scan head. The flatbed scanner utilizes a glass window where the item to be scanned is placed on top of a while the head moves past the item.  This process is similar to the one utilized in Xerox and photo copying machines.

The hand held scanners and required the human operator to move the image or the document over the scanner. They are very small and portable. Initially a light source under the document placed on the screen illuminates. This light separates the black and white dots. Then a motor moves beneath the screen to scan the document. After that the reflected light is focused on a sensor which creates a image of the document and transmits it in electrically signals to the computer which converts it and show the result.

Scanners have only made life simple, by using sophisticated technology. They have availed the facility of Xerox machines at house hold level.

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