I am doing a report on digital imaging, and i would like to know how a scanner scans pictures, and what the bar of light is? Any help that you could give me would be very useful.

-- Jimmy (zingor.geo@yahoo.com), March 01, 2000

Answers

Crumbs Jimmy! You don't want much do you?

Briefly, a scanner is a bit like a digital camera, using a CCD array to convert light to an electrical signal. But in a scanner the CCD only "looks" at a very thin line of whatever it's scanning at any one time, so either the object is moved past the scanners lens, as in some film and sheetfeed scanners, or a long thin mirror is moved across the object to reflect an image back to the lens, as in flatbeds. In this way, the scanner builds up a picture of the object, line by line. i.e. it "scans" it, hence the rather obvious name. The strip of light is a fluorescent tube sitting next to the moving mirror to illuminate the object being scanned.

PS don't blame me if you get an "F".

-- Pete Andrews (p.l.andrews@bham.ac.uk), March 02, 2000.