Scanners

A scanner is a device that optically scans images, printed text, handwriting or an object, and coverts it to a digital image.

There are four different types of scanner - drum scanner, a flatbed scanner, a film scanner and a handheld scanner. Here is some information on all four of them.

Drum Scanner - This is a type of scanner used to capture the highest resolution from an image. The drum scanner gets its name from the clear acrylic cylinder, the drum, on which the original artwork is mounted for scanning.  A light source that focuses on one pixel is beamed onto the drum and moves down the drum a line at a time. Here is an example of a drum scanner -

Flatbed Scanner - A flatbed scanner is usually composed of a glass pane, under which there is a bright light which illuminates the pane. Images to be scanned are placed face down on the glass, a cover is lowered over it to exclude ambient light, and the sensor array and light source move across the pane, reading the entire area. An image is therefore visible to the detector only because of the light it reflects. Here is an example of a flatbed scanner -

Film Scanner - A scanner designed and constructed to scan film only. The optics and transport hardware, as well as the image sensor and supporting electronics are optimized to scan film, not documents or other materials. Here is an example of a film scanner -

Handheld Scanner - Hand scanners come in two forms: document and 3D scanners.This scanner is moved by hand over the material being captured. Handheld scanners are small but partially rely on the user's dexterity to move the unit across the paper. Trays are available that keep the scanner moving in a straight line. Here is an example of a handheld scanner -