[CREATE] [hugin-ptx] Re: Lens correction database

[Pablo d'Angelo]

Hi JD,

>> 2. Vignetting correction:
>> radial correction, radial vignetting correction by division:
>> I = I / (1 + b*r^2 + c*r^4 + d*r^6)
>> The parameters vary with both focal length and aperture.
>> Each focal length and aperture setting require 2 or 3 images for
>> calibration.
> 
> Aren't there 2 other parameters, center of correction, for each of these
> (separately) as well?  Or are these assumed to vary by camera?

Hmm, we still have to check that. I remember reading some papers where the 
principal point (shift of the perspective center) changed with the camera 
orientation. More experiments (measurements with multiple similar cameras) 
are needed to decide if including these parameters makes sense.

ciao
   Pablo