There are a lot of options for remapping images now each with ever increasing
scope. I primarily use a free-ware application called Hugin to implement all my
distortion transformations now, it's extremely accurate and very flexible (much
more so than PS and you know how well that works).
I agree that hugin is a very useable program to deal with panos
and perspective correction.
Just to cite an example when the link for the new fisheye zoom demo pics was
posted a week or so ago I transformed some of the images to see how well they
might work for me, see the following links (btw these are not my images so
apologize to the author). The image bellow was transformed in a single
transformation which took only a matter of seconds after some critical control
points were selected. Both images have been reduced in size by half and the
original image was also converted from Adobe RGB to sRGB color space:
I've got another example that shows the limit of what you can
(reasonably) do. Trouble is, "correcting" perspective can only be done
within the limits of the projection you're trying to go to. Here's the
original of a picture I took going home this Christmas over Ohio with the
Peleng 8mm circular fisheye (and yes, those are *both* wings on the
sides):
http://www.ee.vt.edu/~mythtv/PESO/imgp3342.jpg
Rectilinear (i.e. "normal") lenses cannot mathematically represent 180
degrees of field of view. So, correcting for severe fisheye can remap
perspective, but it's not the lens' fault that things look weird when one
goes too far:
http://www.ee.vt.edu/~mythtv/PESO/imgp3342_defishedrect140.jpg
http://www.ee.vt.edu/~mythtv/PESO/imgp3342_defishedrect150.jpg
http://www.ee.vt.edu/~mythtv/PESO/imgp3342_defishedrect160.jpg
Those are 140, 150, and 160 degrees of horizonal view. I'd say
that 140 is about the most that can be done and still seem realistic.
By contrast, here's an equirectangular projection of the same
shot. Less "fishy" than the original, although straight lines don't stay
straight. At least the whole shot is viewable.
http://www.ee.vt.edu/~mythtv/PESO/imgp3342_defished.jpg
Enough babbling... just figured I'd encourage anyone who hasn't
played with hugin or its other panoramic ilk to play. This correction was
trivial.... set the lens at 8mm, 1.5 crop, and choose how big I want the
output.
-Cory
--
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* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
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