Editing Image scanner (section)

== Scanning elements ==
=== Charge-coupled device (CCD) ===
{{Main article|Charge-coupled device}}
Scanners equipped with [[charge-coupled device]] (CCD) scanning elements require a sophisticated series of mirrors and lenses to reproduce an image, but the result of this complexity is a much higher-quality scan. Because CCDs have a much greater depth of field, they are more forgiving when it comes to scanning documents that are difficult to get perfectly flat against the platen (such as bound books).<ref name=sense>{{cite journal | last=Staff writer | date=July 1999 | url=https://link.gale.com/apps/doc/A54840845/GPS?sid=wikipedia | title=Making Sense of the Sensors | journal=Computer Shopper | publisher= SX2 Media Labs | volume=19 | issue=7 | page=223 | via=Gale}}</ref>

=== Contact image sensor (CIS) ===
{{Main article|Contact image sensor}}
[[File:Overwiew - Scanner unit CIS Canon MP500 5of5.jpg|thumb|Scanner unit with CIS. A: assembled, B: disassembled; 1: housing, 2: light conductor, 3: lenses, 4: chip with two RGB-LEDs, 5: CIS]]
Scanners equipped with [[contact image sensor]] (CIS) scanning elements are designed to be in near-direct contact with the document to be scanned and thus do not require the complex optics of CCDs scanners. However, their depth of field is much worse, resulting in blurry scans if the scanned document is not perfectly flush against the platten. Because the sensors require far less power than CCD scanners, CIS scanners are able to be manufactured down to a low cost and are typically much lighter in weight and depth than CCD scanners.<ref name=sense />

=== Photomultiplier tube (PMT) ===
{{Main article|Photomultiplier tube}}
Scanners equipped with [[photomultiplier tube]]s (PMT) are nearly exclusively [[drum scanner]]s.<ref name=drumdef />