Scanner

A scanner is a computer hardware component which produces digital images by analyzing printed texts, handwritten material, images and other objects.

Types of Scanners:

An image scanner can be of different types such as:

•  Drum Scanner : This uses photomultiplier tubes to hold the information in the form of images. The drum is actually an acrylic cylinder which goes through high speed rotations when a certain item gets scanned. The newer forms of color drums have 3 photomultiplier tubes for reading the colors red, blue and green. The light from the article that gets scanned, is broken separately into red, blue and green under the influence of the optical scanner. The drum scanner can handle “aperture size” and the “sample area” individually. This is a notable feature of the product.

•  Flatbed Scanner : It is made of a glass plate, below which a bright light is placed. The light is mostly cold cathode fluorescent or xenon and its function is to light up the glass. The scanner also has an optical array in the form of CIS and CCD. It has 3 rows of color sensors attached with red, green and blue filters. The images meant for scanning are kept facing downwards on the glass. The sensors and light travel over the glass and the whole area is read.