what are the different of each scanner??
- geek_girlLv 41 decade agoFavorite Answer
► Drum scanner:
Drum scanners capture image information with photomultiplier tubes (PMT) rather than the charged coupled device (CCD) arrays found in flatbed scanners and inexpensive film scanners. Reflective and transmissive originals are mounted to an acrylic cylinder, the scanner drum, which rotates at high speed while it passes the object being scanned in front of precision optics that deliver image information to the PMTs. Most modern color drum scanners use 3 matched PMTs, which read red, blue and green light respectively. Light from the original artwork is split into separate red, blue and green beams in the optical bench of the scanner.
► Flatbed Scanner:
A flatbed scanner is usually composed of a glass pane (or platen), under which there is a bright light (often xenon or cold cathode fluorescent) which illuminates the pane, and a moving optical array, whether CCD or CIS. Colour scanners typically contain three rows (arrays) of sensors with red, green, and blue filters. Images to be scanned are placed face down on the glass and the sensor array and light source move across the pane reading the entire area. An image is therefore visible to the charge-coupled device only because of the light it reflects. Transparent images do not work in this way, and require special accessories that illuminate them from the upper side.
► Film scanner:
A film scanner is a device made for scanning photographic film directly into a computer without the use of any intermediate printmaking. They provide several benefits over using a flatbed scanner to scan in a print of any size — the photographer has direct control over cropping and aspect ratio from the original unmolested image on film, and many film scanners come with specialized software or hardware designed to remove scratches, film grain, and improve color reproduction from old negatives.
</geek>Source(s): http://en.wikipedia.org/wiki/Film_scanner http://en.wikipedia.org/wiki/Image_scanner#Drum_sc...