A scanner is an input device that captures documents such as photographs and text. There are basically three types of scanners:
Drum Scanner : In a Drum scanner, the light from the object that is to be scanned is split into separate red, blue and green beams optically making the image precise
Flatbed Scanner: In this type of scanner, the object to be scanned is placed face down on a glass window, which is illuminated with a bright light.
Handheld Scanner: It is a manual device, which is dragged over the surface of the image to be scanned.