Microfiche scanning

[Pete Turnbull]

On Apr 21 2005, 21:55, John Foust wrote:
> At 07:21 PM 4/21/2005, you wrote:
> >You could just remove the fiche viewer screen.  You don't need the
> >screen to form the image, you only need the (virtual) image from the
> >viewer's lens system to be focussed in the same plane as the
scanner's
> >optics.  Actually, since the image is usually focussed on the back
> >surface of the viewer screen, you'd want to remove it anyway.
>
> Pointing the scanner at the plane in space that happens to be the
> viewing plane of the fiche viewer isn't going to result in an image.
> The scanner wants to see reflected light.  Focusing the fiche
> projection at the scanner's sensor is a different sort of problem
> that would involve changing the scanner's optics, no?

It doesn't make any difference to the focussing of the scanner optics
whether it's seeing an image produced by light reflected from a plane,
or light from some other source producing an image in that same plane.

-- 
Pete						Peter Turnbull
						Network Manager
						University of York