[CREATE] Lens correction database
scb at lo-res.org
Tue Jan 8 11:15:53 PST 2008
[my last x-posting on this topic. reply-to set to
create at lists.freedesktop.org again; in the lack of a
list dedicated to this topic.]
Tue 08 Jan 2008 16:23, Andrew Zabolotny wrote:
> From Tue, 8 Jan 2008 11:36:53 +0100
> sebastian sauer <scb at lo-res.org> wrote:
> > basically all this lens+camera "defect" modelling is also very useful
> > in the geomatics/remote-sensing area. (of course also in computer
> > vision, medical imageing, etc.)
> I wasn't looking that far :) My guess is that specialised applications
> use cameras/lenses far from regular photographic equipment,
to make it less confusing, i'll make it simple :)
basically there are 2 widely used FOSS geomatics programs GRASS and OSSIM,
and basically 3 different user-groups.
1/ people with really fat cash, having access to high-tech *modern* aerial
imaging equipment. (fuckin' expensive, really)
OSSIM supports this stuff..
applanix2ogeom supports non-linear discrete radial lens distortion.
basically you specifiy a parameterfile, which you get from the camera.
2/ people with still quite some budget, having access to old, classic
..these cameras vary, but the higher-end modles among them are like that..
GRASS supports them, but AFAIK assumes that the images are rectilinear.
3/ "ordinary" people that shoot with some standard of-the-shelf, over-the-counter
DSLR, (often with wide-angle / fish-eye, in the hope to get a similar field-of-view
as a professional aerial camera.)
these ppl. somehow not yet realize that exactly e.g. your software will help
e.g. this GRASS user, which for some reason decided to ignore me and my
.. see also there's a whole new generation comming, very cool..
and one of the god-fathers of FOSS geomatics Markus Neteler posted also
a very usful paper and a wiki-page..
> I'm wrong. In any case, I think lensfun will need some improvements to
> be useful in that area.
fact is, you guys here on this list are the actual experts on
lens-models. believe it or not :)
GRASS GIS has nothing for lens correction.
and OSSIM has decent models (what can compare well to commercial
geoformatics software) *but* nothing really advanced.
"OSSIM does have sensor models for aerial frame and pinhole cameras.
A full blown camera model will have calibration information such
as focal length and radial distortion parameters."
> > mmh, maybe an new mailing list, dedicated to photogammetry?
> If you can find more than two interested people, maybe it makes
> sense :)
agreed. maybe the Vision Workbench software makes it more clear how much
overlap we have on this topic..
> But in any case my primary interest is photography, so I can't
> tell much on the subject you're interested in :)
sure, this also doesn't matter. as far as only lens / camera "defects"
are our interests are the same.
also a side topic could be semi-automatic camera-calibration (that means
semi-automatic dedection of e.g. the lens parameters) as there is
already some decent software.
..but this stuff could be added later to lensfun, as an alternative or
enhancement to the lens database.
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