Rogier Wolff schrieb: > On Wed, Oct 28, 2009 at 10:56:08PM +0100, Pablo d'Angelo wrote: >> Implementations of Minimum cut algorithms are widely available, for >> example from the boost graph library or >> http://www.cs.ucl.ac.uk/staff/V.Kolmogorov/software.html (maxflow v2.2 >> is GPL licensed). >> >> I think an implementation in enblend wouldn't be too hard to do, and >> might be simpler than trying to fix all special cases with the current >> approach. > > The current approach, I think, is very good at hiding some differences > between adjacent images. Getting a good initial "cut-line" might help > a bit. But just switching to a "good cut line" according to this > algorithm you described is not good enough. > > I have been thinking about THIS algorithm for the past few weeks. > > Your "edge cost" function I think is too simple. I would add in the > costs (i.e. absolute pixel differences) of a circle around the current > edge.
Actually, I believe that enblend also uses a very similar cost function currently, ie absolute gray value differences, with a much more restrictive state space. Thus I am not convinced that the simple absolute differences cost function is "not good enough", when comparing to the current state. > Suppose we have a person "half" on an image. The intention is to "cut" > completely around this person. (cutting through the person should > incur high costs because the pixels differ a lot.) > > Now suppose a small black line is in front of the person. Now both > images have this line where the "absolute difference between pixels" > is quite low (both black), but closeby pixels DO differ. Of course it is possible to fool this simple cost function, as it is possible with the current enblend. The pragmatic approach would be to first implement the graph cut optimization and then see where the problems with the simple absolute differences cost. Then the cost function can be further tuned. I suspect that maybe adding a soft constraint that tries to keep the seam line closer to the center of the overlap region might also be helpful. ciao Pablo --~--~---------~--~----~------------~-------~--~----~ 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 hugin-ptx@googlegroups.com To unsubscribe from this group, send email to hugin-ptx+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/hugin-ptx -~----------~----~----~----~------~----~------~--~---
