Re: Another camera question

[SCIAMANDA@edinboro.edu]

On Thu, 03 Apr 1997 18:00:11 -0600 brian whatcott said:
> Which reminds me of this story.
> Make a mask (optical filter) from the text 'dog' on a page of print.
> Transform the image of a page of text through the mask.
> When retransformed, all instances of the word 'dog'  are highlighted
> on the reconstituted image along with similar shaped words like "God" etc....
>
> (I never tried this personally)
> Regards
> brian whatcott <inet@intellisys.net>

<It's hard for me to see how this would work.  Anybody believe this and want
<to take a stab at it?
> Altus OK

I think some details have been left out.  This should work:
1) photograph the Fourier Transform of "dog" 
2) place a transparency of this in the Fourier plane (usually the
 focal plane) of a lens which is imaging a page of text.
3) the result should be a filtering which enhances the (spatial) spectral 
components of the word "dog.

Some recent optics books give photographical samples of such "Fourier Optics" 
work.  If interested, I can get specific references.

Bob Sciamanda           sciamanda@edinboro.edu
Dept of Physics
Edinboro Univ of PA     http://www.edinboro.edu/~sciamanda/home.html