[ptx] Optimizations

[Ed Halley]

On Thu, 2005-01-06 at 03:47, David Grant wrote:
> But on the Hugin tutorial by Ed Halley: "Once you get good results, ...

I progressively add variables that I *think* will improve the
optimization.  I start with the Pairwise choice (the default).  Then I
add more.

Once the rough positions (y/p/r) are locked in, I can start to add other
variables that make sense for the project.  Barrel only, for a simple
landscape.  View only, to connect the left and right of a 360.  Barrel
and view, if I think the images don't already have a good enough barrel
correction.

Once you've optimized a new value for the Barrel and/or View for a given
lens, optimizing again should have little effect with the same variables
included on another pass.  (Of course, optimizing again and not
including those variables will leave them alone entirely.)

Thus, once I'm happy with y/p/r, I try y/p/r/b.  Once I have a good b, I
go back to y/p/r for minor re-iterations as I decide which control
points cause problems.  Then a final what-if experiment, trying an
optimization of Everything.  Sometimes I keep those results, but usually
the Everything pass will offer no additional value.

-- 
[ e d @ h a l l e y . c c ]