| Author |
Message |
    
Michael Learmonth
New member
Username: Mlearmonth
Post Number: 2
Registered: 8-2004
| | Posted on Thursday, April 14, 2005 - 10:13 pm: |   |
Can you tell me what the maximum value of barrel distortion correction parameter Panorama Factory will accept? Wouldn't a fairly large barrel distortion correction applied to a fisheye image essentially convert the image to rectilinear one which could then be warped and stitched in the usual manner? |
John Strait
Moderator
Username: Jstrait
Post Number: 174
Registered: 5-2001
| | Posted on Tuesday, April 19, 2005 - 9:04 am: | |
Barrel and pincushion distortion (see Correct barrel distortion for examples) are characterized by the percentage change in magnification from the center to the nearest edge of the image.
The Panorama Factory will accept values for barrel and pincushion correction up to plus-or-minus 100%, i.e. a doubling or halving of the magnification. Automatic detection of the barrel correction is limited to a smaller range, approximately plus-or-minus 6%. However, you can enter larger values manually on the Camera properties dialog box and the Overlap region dialog box.
Unfortunately, this correction will not correctly convert a fisheye image to rectilinear. Although barrel distortion and fisheye distortion appear similar, they actually are mathematically distinct. In a barrel distorted image, magnification is a linear function of radius. In a fisheye image, the radial position of a point on the fisheye image is a linear function of the viewing angle. These are different functions, and although they may produce similar results for small viewing angles, at large angles they produce significantly different results.
This means that a correction for barrel distortion cannot be used to convert a fisheye image to rectilinear format.
I'm sorry, I wish I had a better answer for you.
|
Andrew Ross
New member
Username: Arossphoto
Post Number: 1
Registered: 5-2005
| | Posted on Tuesday, May 03, 2005 - 11:16 pm: | |
"This means that a correction for barrel distortion cannot be used to convert a fisheye image to rectilinear format. "
So are you saying there is no way to do a decent panorama with images shot with a fisheye? I have been trying to stitch three shots taken with my Canon 15mm fisheye on my D60. The resulting pano is pretty good and I thought it would need some small adjustments to fix it up. I have been trying to manually adjust the barrel distortion, but no matter what I do it just gets worse.
I have attached a couple crops of the overlap area and would appreciate any suggestions to fix these problems.
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John Strait
Moderator
Username: Jstrait
Post Number: 180
Registered: 5-2001
| | Posted on Wednesday, May 04, 2005 - 9:15 am: | |
Although the fisheye transform is not supported by The Panorama Factory, a few people have reported varying amounts of success with fisheye images.
If you are getting results that are close, you might be able to make the final corrections using manual fine tuning. I recommend you read the web pages the web pages Fine tuning the image alignment and A fine tuning challenge. These web pages explain how to use the manual fine tuning to correct image misalignments on a local scale.
(Message edited by jstrait on May 04, 2005) |
Brian Sullivan
New member
Username: Briansullivan
Post Number: 1
Registered: 1-2007
| | Posted on Friday, January 12, 2007 - 5:35 pm: | |
What is the current status on support of fisheye lenses (as of v 4.4)?
I purchased this product thinking that such support would be standard. It seems was not a good assumption. Am I mistaken in this?
Is such support on the near horizon? |
