Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!sun-barr!decwrl!ucbvax!hplabs!hpda!hpcupt1!hprnd!tms
From: tms@hprnd.HP.COM (Thomas Skibo)
Newsgroups: comp.graphics
Subject: Re: COLOR SCANNING.
Message-ID: <2300002@hprnd.HP.COM>
Date: 6 Dec 89 20:40:56 GMT
References: <13428@s.ms.uky.edu>
Organization: HP Roseville Networks Division
Lines: 27


/ hprnd:comp.graphics / munish@ms.uky.edu (Munish Mehra) /  2:25 pm  Dec  5, 1989 /
> There are many scanners that scan images into 16,32 or more gray levels .
> (Some very reasonable)
> Is it possible to use color filters / colored cellophane paper to
> scan an image through Red, Green and Blue Filters and then combine
> the RGB values to create a colored image ?

I tried a similar approach with a B/W video camera and did not achieve very
good results.  The problem was that the video camera was not equally sensitive
to all visible colors.  The three filtered images were not true representations
of the red, green, and blue components.

Some problems you may run into with the scanner:

1) The light source in the scanner is not bright enough to go through the
   filter paper and the scanner's dark/light adjustment cannot compensate.
2) The light source in the scanner doesn't cover the visible color spectrum
   very well thus making it really tough to capture one or more of the primary
   color components.
3) The scanner is not equally sensitive to all the colors.


							Thomas Skibo
							Roseville Networks Div.
							Hewlett-Packard
							tms@hprnd.hp.com