[ptx] vignetting function estimation

[J. Schneider]

Hi Pablo,

 > 2. Graphical display of vignetting correction polynomial. 3. Feature
 > to optimize this polynomial based on the overlapping images. This
 > function can only estimate the polynomial for the quotient approach
 > right now.


There is no binary yet for us non-programmers to try this? I would be 
very interested!

regards
Joachim

(sorry I didn't post this to the list at first)