[ptx] new reference for stitching algorithms

[Aseem Agarwala]

Hello, Rick pointed me to this discussion about my recent paper / 
software on panoramic stitching 
(http://grail.cs.washington.edu/projects/photomontage/).  I thought I 
would introduce myself and offer to answer any questions on it.

First, a quick note on what it offers for panoramic stitching. 
Essentially, in areas of overlap between the source images, the software 
will choose places to "cut" between the images such that you won't 
notice the seams.  So, if there is parallax or moving people, the 
software will choose to cut AROUND these artifacts.  It works pretty 
darn well, and the software has been released under GPL.

I've been corresponding with Tim Jacobs about his compiling trouble; 
hopefully we'll have them resolved, soon.  Be aware a windows executable 
is also available to download.

The software currently can essentially operate on the same input as 
enblend: images that are already aligned into one space.  However, there 
is one caveat.  The software currently treats pure black as 
"transparent."  If an image has an alpha channel, the software will just 
ignore it, and treat the whole thing as opaque except where the pixels 
are black.

The above is probably pretty annoying.  In the short term, I can offer 
two solutions.  One, if you just want to see if the software has 
anything to offer you, email me your most difficult and nasty stack of 
4-channel, aligned images, and I will stitch it for you.  Two, I have a 
command-line only version of the stitcher that can handle 4-channel 
images, so I could also GPL and release that.

Thanks for the interest,
Aseem Agarwala
http://agarwala.org