Vignette and Exposure Calibration and Compensation
All photographic images have some degree of vignetting, a gradual
darkening of the image toward its periphery. We have developed a
technique to calibrate and remove vignetting, using only a sequence of
images such as those used to create a panoramic mosaic. We can also
recover exposure variations between the frames in the sequence.
Although the radiometric response of the camera or film is needed to
recover relative radiance values, it need not be known in advance if
all you need to do is remove vignetting from your images. Details
are given in the ICCV '05 paper.
Below are some results using this technique. With the name
of each sequence I note whether I used the constant-exposure or
varying-exposure version of the algorithm, and whether the response
curve was known or unknown. The first column shows the original
images, aligned using AutoStitch and composited without blending
(ie. A over B). The next shows the results of Photomontage blending,
which doesn't remove vignetting artifacts but does a good job of
hiding seams. The third column shows the results of vignette
correction without blending. The fourth column shows vignette
correction and blending.
|
Aligned Originals |
Vignette/Exposure Corrected |
Photomontage Blending Only |
Both Vignette/Exposure Correction and Blending |
Allen Center (Constant Exposure, Known Response) |
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Allen Center (Varying Exposure, Known Response) |
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Senore (Constant Exposure, Unknown Response) |
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Green Lake (Varying Exposure, Unknown Response) |
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Apollo 11 (Varying Exposure, Unknown Response) |
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Apollo 17 (Varying Exposure, Unknown Response) |
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Publications
Dan B Goldman and Jiun-Hung Chen. "Vignette and Exposure Calibration
and Compensation." Proceedings of ICCV '05, Beijing,
China, October 2005, pp. 899–906. [PDF, BibTeX]
Dan B Goldman and Jiun-Hung Chen. "Vignette and Exposure Calibration
and Compensation." Poster. Symposium for Computational Photography
and Video '05, Boston, MA, May 2005. [PDF]
Downloads
By request, I have placed my project data (source images, corrected
images, and panoramas) online (Gzipped TAR
file, 379M).
I am also making the python source code available under the X11
license. It's probably too slow for practical use, but if somebody
out there would like to make a more usable version, here's a starter
kit! (Gzipped TAR file, 168K).
Links
Acknowledgements
Portions of this work were initiated while Dan Goldman was a research
engineer at Industrial Light and Magic, a division of Lucasfilm.
Dan Goldman
dgoldman at cs dot washington dot edu