autopano-sift-C f15

[Ian Malone]

On 27 September 2011 21:41, Bruno Postle <bruno at postle.net> wrote:
> On Tue 27-Sep-2011 at 01:14 +0200, Kevin Kofler wrote:
>>
>> Bruno Postle wrote:
>>>
>>> Note that Hugin panorama stitcher now has a fully working
>>> patent-free replacement for autopano-sift-C (you need to reset your
>>> Hugin preferences to enable this), so there isn't really any need
>>> for rpmfusion to carry this package after F16.
>>
>> What makes it patent-free?
>
> autopano-sift-C has an implementation of the SIFT technique, and the
> alternative panomatic implements SURF.  Both algorithms are apparently
> patented, so neither tool could go into Fedora.
>
> This was a problem, so Pablo d'Angelo (the original author of Hugin) wrote
> cpfind, which uses code from panomatic but has an entirely novel feature
> detector.
>

Thanks for the tip. I discovered that I had to re-import the default
control point detectors to get the Fedora 15 ones (I've just upgraded
this system).

>> Is the quality of the output comparable?
>
> Yes, the cpfind in Hugin 2011.0.0 is much more reliable than
> autopano-sift-c, but not necessarily faster.  Unfortunately 2011.0.0 didn't
> make it into F15, though it will be in F16.
>

Trying cpfind on a few panoramas with 2010.4.0.854952d82c8f I've found:
2 where results were acceptable (similar to sift)
1 where results were worse (a very dark image which neither could
automatically handle, but sift was able to cope once some manual
points were added).
1 where cpfind performed better (correctly connected end image of 5,
whereas sift anomalously connected it to the wrong image).
If 2011 is an improvement then on this limited evidence I couldn't complain.

Further question then while on the topic: libpano13 is apparently
compiled with a 179 degree limit to avoid a patent on hemispherical
coverage (aren't patents great?) does anyone know if that limit been
circumvented? (The actual patent, not the number in the source code. I
don't even know if it's much of a problem for single row panoramas
anyway).

-- 
imalone