RE: flatbed scanhead in rotating camera

[Mike Sinclair <sinclair@xxxxxxxxxxxxx>]

Thanks for the post David. 

I should have also pointed out that 42mm (length of the active area on many
tricolor CCDs) is also the diagonal of a 35mm film aperture and the minimum
diameter of coverage for most 35mm lenses. Also, the Russian 16mm Zenitar
(www.russia2all.com) will yield its 180 degree FOV over this length sensor.

You're right about squaring up non-square pixels by changing the aspect
ratio through stretching. This is what I have to do to make the 11"
flatbed-scanning-dimension fit into a 360+ degree swing. This results in
severe aspect ration problems but can be repaired at the cost of wasting a
lot of pixels.

Thanks for your input.

-Mike-

> -----Original Message-----
> From: ADavidhazy [mailto:ANDPPH@xxxxxxxxxxxxxxxxxx]
> Sent: Thursday, June 22, 2000 6:06 AM
> To: panorama-l@xxxxxxxxxxxxxxxxx
> Cc: ANDPPH@xxxxxxxxxxxxxxxxxx
> Subject: RE: flatbed scanhead in rotating camera
>
> Mike,
>
>> I think you're on the right track but may run into some problems. To get
>> scanner software/firmware to move the sensor head farther than the
factory
>> length of the bed itself is next to impossible (but if you do, PLEASE
share
>> it!). <snip>
>
> Words of wisdom!
>
>> 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.
>
> Yup ... or, if you tolearate fixing things after the fact you can scan
always
> to the same length and then stretch using software by interpolation to a 
> longer length.  ;-)  
>
> BTW, a 42mm sensor is actually not too bad. In my improvised camera I am
using
> a  only 20mm or so sensor which is really not very good in terms of
quality but
> the purpose was only to have a "demo" system for teaching purposes.
>     
> The bottom line is that I think you have neatly summarized the problems
and
> possible solutions. Thnaks.
>
> Andrew  o o  0 0 o . o  Davidhazy, Imaging and Photo Tech
>          \/\/\/\/\/\/          http://www.rit.edu/~andpph
> __________|        |_____________________________________