RE: flatbed scanhead in rotating camera

[Ernst Dinkla <ernst@xxxxxxxxxxxxxxx>]

In <URL:news:lokaal.panorama> on Thu 22 Jun, Mike Sinclair wrote:

> Another thing that probably won't work that was suggested is putting the
> flatbed scanner "as is" in the film plane - you don't have a real image!
> You'll need something for the camera to produce a real image like ground
> glass....but this is a BAD way to do it. Instead, put the tricolor CCD
> sensor physically in the image plane (without the 5+ mirrors that are in the
> image path of most flatbed scanners) and mechanically scan it across the
> film plane. Of course this will only digitize a 42mm wide path in the image.
> Use different gearing to move it the required distance to give you square
> pixels - for the case of a rectilinear camera with a flat film plane. 

You are right of course. The only way to get the virtual image from the
film plane to the CCD would be with light conducting fibres or a small
etched strip of glass in the film plane moving along with the CCD.
Would a rod of glass on the same spot work as an additional optical
element? It needs to get the width of the pixels in the optical path of
the scanner. I'm still thinking that where it passes the optical axis of
the lens there will be a hot spot.

Using the CCD only will change the aspect ratio and I think that
changing the gears will be limited by the design of the bearings etc.
A 600 ppi A4 scanner will have a 3000 ppi CCD so the steps will
have to be 5 times smaller. Still a nice area of 42 x 60 mm.
But you don't need a large enlarger for it.

Makes me wonder whether the new true 1200 ppi flatbed scanners can't be
rebuild to panorama film scanners at 1200 x 6000 ppi and some nifty
resampling software. Reducing the gears by a factor two would give an
area of 150 x 42 mm and 2400 x 6000 ppi. Another lens is needed to get
the distance between the film and the CCD.

Ernst
-- 
Ernst Dinkla  Serigrafie,Zeefdruk            The point will never be metric