On Sun, 23 Oct 2011 00:59:27 -0700 (PDT), kfj wrote: > On 22 Okt., 16:49, Robert Krawitz <[email protected]> wrote: > >> 2) I'd like a more convenient way to delete all control points in a >> region in an image, with a choice of just deleting all points in >> that region between a pair of images or all control points. >> ... >> The use case I have for this is that I frequently take hand-held >> landscape panoramas where the foreground is not in alignment > > I do the same. What I find is that I get good results by simply > removing all CPs outside a strip along the horizon. I do this using > my 'crop CPs' plugin. It's a bit of a crutch since you can't select > a random area - instead it misuses hugin's output cropping feature > by removing the CPs inside or outside the cropping area. So you're > restricted to rectangular areas - but usually I find throwing away > all CPs outside a strip near the horizon does the trick.
That sounds like a useful starting point (although I often have to remove points from the sky also, when celeste doesn't do what it should, and in mountainous regions a rectangle isn't sufficient). Is this part of the hugin repo, or is it a separate download? The other problem is that in the very early stages, when this would be most useful, sometimes it's not possible to get something well enough aligned to do this. >> Often cpfind puts so many points in the foreground that the worst >> error is in the background points -- the ones that I know are good. >> So I can't simply remove outliers at that point. What I have to do is >> go to each image pair in turn and go through each point, deleting the >> ones I don't want. Once I get rid of enough of the foreground points, >> the remaining ones become the outliers, and then things move much more >> quickly. Unless there's a particularly strong texture in the >> foreground (like a crack in the rock), these panoramas usually stitch >> very well, despite very large error in the foreground. So there's no >> point in having any points at all in the foreground. > > Looks like you'd be happy to just do just what I do. The trouble is > that my crop CPs plugin doesn't fully function on all platforms. If > you're on Ubuntu you're lucky: it'll use wxPython to display a > little choice box asking if you want to remove the CPs inside or > outside the cropping area. This may or may not work on other Linuxes > and Windows. On MacOS there are no plugins yet. And you do need an > hsi-enabled build. I run OpenSUSE 11.3. I know wxPython works in general here, and if there are problems, I'd be happy to debug them. >> I could use a mask on each image in turn, but that's not a lot less >> tedious. > > Tedious ideed. Using my plugin it's very quick: set cropping area, > run plugin, reset cropping area. Takes a few seconds. I use it for > nearly all my landscape panos; I take them with the lens tip resting > on my walking stick, so they're slightly better than handheld but > definitely have parallactic errors in the nearby areas. As you have > observed, these aren't much of a bother in the final stitch since it > rarely matters if a few blades of the lawn you're on are misplaced - > it's much more relevant that there aren't any jumps in the > horizon. And as you've also observed - once the error-prone nearby > CPs are gone, the optimization using only the relatively > parallax-free further-away points comes out much better. The other problem I have is that there are usually some control points that cpfind doesn't place correctly. These are very hard to find until I've purged the foreground CPs. So purging the foreground points is always the essential first step. For small panoramas with only 2-4 images it's not too bad, but I often do 10-15 image panoramas, and I like to use a lot of overlap, which results in quadratically increasing work (*my* work, not the computer's) to clean up. I can only think of a handful of panoramas where I actually did need to perform significant cleanup after the fact; one involved a large crack in the rock in the extreme foreground, one a shadow that was a problem in part due to the planetary rotation, and one some balloons moving. The latter two, of course, were not perspective problems. Unless I have focus or motion blur problems, it rarely matters even if I can find the seam, which usually I can't. -- Robert Krawitz <[email protected]> Tall Clubs International -- http://www.tall.org/ or 1-888-IM-TALL-2 Member of the League for Programming Freedom -- http://ProgFree.org Project lead for Gutenprint -- http://gimp-print.sourceforge.net "Linux doesn't dictate how I work, I dictate how Linux works." --Eric Crampton -- You received this message because you are subscribed to the Google Groups "Hugin and other free panoramic software" group. A list of frequently asked questions is available at: http://wiki.panotools.org/Hugin_FAQ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/hugin-ptx
