A scanner is an optical device that reads a printed text or image and
It converts into a digital graphics image for the computer.
A scanner works by digitizing an image. Scanner split
Image in a grid of dots and either represent each dot with a zero
Or one. The resulting matrix of bits, called a bit map, can occur
Stored in a file, displayed on a screen, and manipulated by programs.
Scanners can be mainly divided into three types: flatbed, handheld
And drum scanner
(1) Flatbed scanner: A flatbed scanner is one which provides a flat,
Glass surface for placing pages of paper, books and other objects for scanning.
The scan head is moved under the glass across the page to be scanned.
Image.
(2) Handheld scanner: A handheld scanner is one that is crossed
Image to be scanned by hand. Handheld scanners are small and
Less expensive, but it depends on the accuracy of the user to move the unit
Across the image. Trays are available that keep the scanner running
in a straight line.
(3) Drum Scanner: A drum scanner is a type of scanner on which
The original artwork is attached outside a spinning glass drum.
The image is scanned by photo multiplier tubes (PMTs) and saved to disk.
File. This type of scanner gives the best quality results. These are many
is costly.