[ptx] new tutorial on TCA correction

[Bruno Postle]

On Wed 15-Mar-2006 at 23:01 +0000, Bruno Postle wrote:
> On Wed 15-Mar-2006 at 08:52 +0100, Pablo d'Angelo wrote:
> >
> > Please take a look at my tutorial on estimation of the TCA correction
> > coefficients at:
> >
> >  http://hugin.sourceforge.net/tutorials/tca/en.shtml

> Though playing with the values, it seems to create wrong output.  

My mistake, the output is fine, the maths in the tutorial and the 
javascript calculator give good results.

I found that optimising just c and fov for the red and blue channels 
gave the best output for me.

A couple of points:

Hugin CVS has a bug that makes it difficult to change the input 
projection (I eventually managed to set it to equirectangular by 
selecting every other projection in turn).

The tutorial says to run this octave command:

  octave:2> display_tca('pano_tutorial.pto');

..the correct command seems to be:

  octave:2> show_tca('pano_tutorial.pto');

Though I can't see much difference between the fulla output when 
using PTOptimizer and when using the octave script - They seem to be 
as good as each other to me.

In my tests, the red and blue channels were both scaled down leaving 
an ugly green border around the photo.  Can the calculation for the 
fulla parameters be adjusted to scale everything so the smallest 
channel fits the image width?

-- 
Bruno