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Message from discussion Radial distortion model in PanoTools

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More options Oct 15 2012, 4:12 pm
From: "Carlos Eduardo G. Carvalho (Cartola)" <cartol...@gmail.com>
Date: Mon, 15 Oct 2012 17:12:48 -0300
Local: Mon, Oct 15 2012 4:12 pm
Subject: Re: [hugin-ptx] Re: Radial distortion model in PanoTools

I made myself the same question: what do you want to accomplish with all
also didn't understand the math).

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.

Here is the hugin tutorial I mentioned:
http://hugin.sourceforge.net/tutorials/calibration/en.shtml

Bests,

Carlos E G Carvalho (Cartola)
http://cartola.org/360
http://www.panoforum.com.br/

2012/10/15 Erik Krause <erik.kra...@gmx.de>

> 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

> best regards
> --
> Erik Krause
> http://www.erik-krause.de

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