Re: The Keystone Effect

[P3D <CJMCE@xxxxxxxxxxxxxxxx>]

Andrew Woods said:

>Keystoning caused by the camera could be removed by projecting the two 
>images with the appropriate reverse projection keystone distortion.

In a darkroom this can be used to produce an affine rectification - a "trick"
cartographers used for decades BEFORE the advent of digital images.  We did
it so that we could panel graticules (the lines of latitude & longitude) from
one type of map projection to another type of map projection.

NASA was interested in having this "stretching" and projection change done for
some project back in the early seventies.  I wrote a proposal & described how
to do Affine Rectifications along with how much it would cost.  They were
shocked to find out hou simple and inexpensive the process was ... needless to
say, it was dropped from consideration since there was insufficient 
technological panache.  Wasn't stereo, either.


Clifford J. Mugnier  (cjmce@xxxxxxx)
Topographic Engineering Laboratory
Department of Civil & Environmental Engineering
University of New Orleans
New Orleans, Louisiana  70148
Voice: (504) 286-7095
FAX:         286-5586


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End of PHOTO-3D Digest 1334
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