[ptx] auto fine-tune on large images

[Pablo d'Angelo]

Rich schrieb:
> auto fine-tune is a nice tool, but on large images autotuning single 
> point can take a lot of time.

How large are large images? And how many of them are in your project.

> what could be done to speed up this process ?
> 
> i checked finetune preferences and didn't change any parameters that 
> were specified in pixels, only reduced 'search area width' (which didn't 
> help a lot though, and it seems that it is constantly reset back to 10%)
> (rotation check is disabled)

Ok, will check that. It shouldn't pop back to 10%.

> a big part of this process is some sort of grayscale generation. is this 
> done for some small region around added control point or for whole image 
> ? if this is done for a small area, it's extremly slow. if it's done for 
> a whole image, why is it done every time an auto finetune is performed ?

Currently its done for the whole image, but it should be done only once, 
  and then stored for further use. Also, it shouldn't be terribly slow. 
By default, hugin uses ~ 80 MB to cache images (both the color images as 
well as the grayscale images).
It might help to increase the Image Cache size to something bigger. It 
can be found in the Preferences on the "Misc" tab.

> finetuning a single point to two images (rows for multirow panorama) 
> takes approx 15 minutes, so probably a lot of information is parsed that 
> gives no real benefit, but i could not find a way to reduce this time

Hmm, that is strange. How much memory do you have, and how fast is your 
computer?

ciao
   Pablo