Hi, Klaus, my camera has "infinite" number of zoom positions, as it has seamless zoom from 6.3 to 63 mm (38 to 380 mm if we speak in terms of 35 mm camera). So it seems to me, that there is no lookup table, but lens distortion parameters are calculated.
Regards Jaroslav On 30 Říj, 16:27, Klaus <[EMAIL PROTECTED]> wrote: > Hi Jaroslav, > > On 30 Oct, 14:52, "Jaroslav.Beran" <[EMAIL PROTECTED]> wrote:> as you can see > from my post, lens distortion parameters vary with > > focal length. > Yepp. > > There is a high possibility, that they also vary with each camera of the > > same model. > > There I wonder, whether eaach camera is measured indeed and provided > with its individual parameter set. Given the needs of mass production, > I somewhat doubt it.> But - if they vary with focal length, it seems to me, > that they are calculated by the camera during the shoot. > > At least with my cameras, there is only a finite number of zoom > positions. So I suspect a rather small lookup table. > > > But that was not the point of my questions/suggestions. I'm just > > curious, why these parameters are not used directly by Hugin. > > Honestly, I cannot say why not. But I suspect reasons among the > following: model for coefficients not documented, several different > models, different model to the panotools framework, need to actually > code and implement it. And most importantly: no big problem to > determine the actual parameters from image data. Without the need to > decode different EXIF entries with different models from different > manufacturers. And it describes your individual lense. > > > Why do I have to difficultly determine lens distortion parameters myself, > > when camera does it for me? > > I challenge the perception of "difficulty". Hugin does it for you, at > the expense of marginally more control points. > > > I'm not questioning, how much control points do we have to use - the > > more control points, the better... > > > Anyway - how about other cameras? Do they also save lens distortion > > parameters in EXIF? > > There is a research project for someone - and do they use the same > mathematical framework? > > > And - much more important question - wouldn't be nice, if Hugin could use > > them? > > My opinion is: while the hugin lense model has a mathematical > shortcoming, it is still good enough to describe your lense > distortions to subpixel accuracy. I doubt the additional benefit is > worth the effort, but anyone who wants to tackle this particular > aspect is free to write some code. > > Regards > Klaus --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "hugin and other free panoramic software" group. A list of frequently asked questions is available at: http://wiki.panotools.org/Hugin_FAQ To post to this group, send email to hugin-ptx@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/hugin-ptx -~----------~----~----~----~------~----~------~--~---
