[ptx] Enblend Multiresolution Spline Blender

[Pablo d'Angelo]

On Sun, 07 Mar 2004, Andrew C Mihal wrote:

> On Sun, 7 Mar 2004, Pablo d'Angelo wrote:
> 
> > Hmm, seems to take quite a while on these big images.. ;)
> > Actually I'd like to incoporate the blending stuff into nona. The seaming
> > lines could also be calculated from the info created during the remapping,
> > like the angular distance, instead of thinning the masks.
> 
> Yeah, the thinning is really slow. But it is general enough to work on 
> overlap regions with very complicated shapes. If you have a mathematical 
> model of the outlines of the images, there are faster ways to get the 
> transition line. There are lots of Medial Axis Transform papers that talk 
> about this. I haven't read these.

Mine either. However, during stitching, nona calculates the distance (in
original pixel units, before remapping) from the image center for each point
in the panorama (for all images). I think it should be easy to use this to
create the needed mask

This is how I currently place the seams in nona.

Here is my proposed (panorama specific extension):

1. build a graph of the overlapping images.

3. blend all image roi's after each other, by doing a breadth first
   traversal of the overlap graph. (blends all images starting from one).
   use the distances for each image to calculate the seam line.

 4. remember calculated pyramids if they are still needed.

I'm not sure if this is the best way. Actually have user editable seams for
all images would be nice. The memory requirements would be greatly reduced,
since only the final image, the image roi's and their distance map are held
in memory. During the blending step, only memory for the pyramids for two
image regions would be needed.

Another thing I was thinking about, was the creation of a gimp plugin. this
wouldn't benefit so much from information of the stitching process, but the
mask could be easily edited in gimp to mask out unwanted areas. It might
also be useful for other tasks than blending in panoramas.

ciao
  Pablo