I once have calibrated a fish eye lens with the hugin tutorial. It took me
some hours to make the pictures, understand the concepts and achieve a good
result. Later I have discovered that I didn't need to do that to make a
full sphere panorama. Hugin - and probably PTGui - can do the necessary
distortions based on control points and in a defined angle - like the 360
of the full sphere.
> Am 15.10.2012 15:15, schrieb lireful:
> I have calibrated a fisheye lens using Kannala model, which is
>> basically a polynomial R(theta), where R is the polar coordinates
>> radius of current point. Now I have a need to work with this
>> calibration in PTGui. We use Canon APS-C matrix crop-factor 1.62,
>> 4272x2848 matrix in the landscape mode, 8 mm Sigma fisheyes.
> You should have asked on the PTGui mailing list first of all...
> Sorry, I don't understand the math you provided, only one point: r = 1 in
> panotools is not half the width, it's half the shorter side. And perhaps
> its worth mentioning that the original panotools model (which is used by
> PTGui) uses the abc parameters to handle the deviation from the R=f*theta*m
> model, not the fisheye distortion itself.
> However, I don't understand what you want to accomplish. If you simply
> want to calibrate your lens for taking panoramas, do exactly this: take a
> panorama (no zenith or nadir for that task), least-parallax-point set up
> the best that is possible, no near detail, with a lot of overlap and enough
> structure throughout the whole image, put it in hugin or PTGui, create
> control points and optimize. That's all that is needed.
> Maybe I misunderstand the whole model?
> I guess you read http://wiki.panotools.org/**Lens_correction_model<http://wiki.panotools.org/Lens_correction_model>
> To see the model in action while you play with the parameters you can
> download abc.xls from http://4pi.org/downloads/
> best regards
> --
> Erik Krause
> http://www.erik-krause.de
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