[ptx] nona vs. PTStitcher

[Bruno Postle]

On Fri 08-Apr-2005 at 13:05 +0100, Bruno Postle wrote:
> 
> - Chromatic abberation correction.  Nona could become capable of
> remapping each RGB channel seperately.
>  
>  There ought to be a way of determining this automatically just by
>  looking at a photo.

Here is an example of doing this semi-automatically:

1. Use the gimp decompose filter to split an image into separate
   red, green and blue images.

2. Then run autopano-sift or hugin/finetune on the three images to
   generate control points.

3. Then optimise the field-of view of the red and blue channels
   while using the green channel as an anchor (you could optimise a,
   b & c parameters as well as field-of-view).

This should produce three different scale ratios that can be used to
recompose the channels into a 'chromatic aberration corrected' RGB
image.

I tried a test, but I only have jpeg photos to hand and they are
useless for this kind of thing (most colour information is lost
during jpeg compression).  This process really needs to be done on
tiff or raw images.

-- 
Bruno