[ptx] panosifter problems & questions

[scholnik at radar.nrl.navy.mil]

Hi -

	I've been playing around with panosifter since it appeared in CVS
and had some success, primarily with narrow-angle (36-108mm equiv)
shots near the horizon.  I just did a 1+ row 360 pano with 45 total
1200x1600 shots, and it found matches for most of the overlaps.  Now
I've got a new camera with a 19mm (equivalent) wide angle lens and I'm
finding things a lot more difficult.  I just did a 2 row x 9 portrait
shots/row (about 33% overlap) + zenith and panosifter is not finding
many matching photos, no matter the subsampling parameters I use.
When I go into hugin to add points myself I'm finding that
auto-estimate and fine-tune aren't working so well either.  I'm
assuming this is because hugin and panosifter don't de-warp
(pre-warp?) the images and are looking for pure translations?  Are
there any plans for using rough yaw/pitch/roll/fov/abcde estimates to
project the current two images to a common reference frame for
control-point picking?  That would be especially helpful (neccesary,
really) to stitch the zenith/nadir.

   While I'm complaining about free software :) I thought I'd mention
some other things I noticed:

1. panosifter tries to read focal length and sensor size from the exif
   data, but when it can't find the sensor size it throws an error and
   assumes 24mm x 36mm.  My camera stores the true focal length but it
   has a cropping factor of about 5, so assuming 24mm x 36mm is really
   wrong.  I do use the -v parameter but I think it is being ignored.

2. Sometimes panosifter decides that two images overlap (I guess) and
   puts them in the same .pto file, but with no control points at all.
	Other times it just makes .pto files with a single image.

3. The recent CVS panosifter seems to be broken; it decides that every
	image matches every other image, and uses the same set of points
	for every image pair.

I can provide images or debugging output upon request.

-- 
Dan Scholnik