Re: Another camera question

[David Dockstader <DRDOCK00@UKCC.UKY.EDU>]

   Something like 25 years ago when I was working at Kodak we experimented
with using the technique you describe to do image enhancement.  We did
an optical Fourier Transform, made maskes to adjust the relative amplitude
of various frequencies, and then Transformed back to reconstruct the photo
You have to remember that in those days computers aren't what they are today
so scanning a photo into a computer and doing the Fourier Transforms was quite
a strain on the computer for high resolution pictures of any size.

On Wed, 02 Apr 1997 17:28:21 -0600 brian whatcott said:
> At 05:36 PM 4/2/97 EST, Paul Camp wrote:
> > Some of them use a contrast sensor, a light sensitive surface in the
> > image plane that seeks maximum contrast in the image...
> > Paul J. Camp
>
> I'm with Paul on this one.
> To put it another way, the maximal spatial frequency component in the image
> area of interest is attenuated.
>
> Which segues into another possibility for a discard camera:
> with a translucent screen or perhaps greaseproof paper in the image plane,
> and a low power laser expanded onto a 35 mm transparency
> at the focal plane distance in front of the camera lens, this is a low cost
> demonstration of spatial fourier transforms.
>
> Vertical bars at the forward plane transform to a pair of spots in the
> horizontal direction of the image plane and so on.
> An optical atlas of transforms would be a handy reference here.
>
> A further step in sophistication is to provide an optical filter at the
> image plane ( central hole = low pass ) and use another lens to transform
> the filtered image back to its original form where the effect of high pass
> or low pass filters can be observed.
>
> Regards
> brian whatcott <inet@intellisys.net>
> Altus OK