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

[Jim Watters]

Hugin also evaluated the quality of the overlap by using a difference 
between two overlapping images. We can actually use the histogram of the 
difference to evaluate the overall quality of the settings.  An older 
version of PTOptimizer actually used this method to determine 
correctness instead of control points.  Would require a ghost removal to 
eliminate sections to be evaluated. But I would like to see using 
histogram of difference as a way to optimize lens distortion at least, 
but only between a couple images for speed issues.

Jim

Pablo d'Angelo wrote:
>> During the stitching process, hugin evaluates the quality of the 
>> optimisation by calculating error distances, why not improve this 
>> with some extra checks and give the user an option to upload the 
>> results from _all_ good optimisation passes.
>>     
> I like this idea.
>
> This could happen through uploading an anonymized pto file (image filenames 
> etc. removed) to some central server. Since often multiple optimisation will 
> be done before the final panorama is created, it might be a better idea to
> upload the data when the user actually renders the panorama.
>   
>> eg. a field of view calculation is only credible if field of view 
>> was actually optimised and there are a large number of well-spread 
>> control points involved with a low error distance.
>>
>> Then the task of compiling the distributable database is statistical 
>> analysis of this collected raw data, removing outliers, averaging 
>> and interpolating.
>>     
>
> The drawback of deriving these parameters from ordinary panoramas are 
> inaccuracies due to parallax errors, moving objects etc. I suspect many
> users of hugin are satisfied with panoramas that do not lead to a good 
> calibration. So some effort needs to be spend on determining a good way
> to reject those. Maybe some simple rules based on distribution of the points 
> and the might be enough, but that needs to be evaluated.
>
> The good thing is that both the "manual" calibration approach and this 
> upload based approach can be combined :-) So we can start with
> the calibration based one, and later add the more automatic, upload
> based approach.
>
> ciao
>    Pablo

-- 
Jim Watters

jwatters @ photocreations . ca
http://photocreations.ca