Hi Brent, Brent schrieb: > From a purely empirical point of view, it appears that there is some > undesirable linkage between these parameters that makes the > minimization process get trapped into local minima and have difficulty > finding a solution in some cases.
I have had the same problem, with both the tilt parameters (TiX,TiY,TiZ, TiS) and the position parameters (TrX, TrY, TrZ). The problem that the optimizer gets trapped in local minima isn't really something new, so we have worked a bit around that with multi-step optimization, and especially the incremental optimization in hugin and autooptimizer (cmd line optimisation program, part of the hugin package). I found that with adding image by image to the optimisation process, I didn't get really bad random behaviour anymore, even when later "finetuning" the project and doing reoptimisations, as the project is already close to a nice minima (I hope....). As for correlation between the parameters, I quite sure that d,e and TrX, TrY are highly correlated when using rectilinear images, especially if they are shot without large variation in yaw and pitch. In my experiements with the graffiti wall example posted by Bruno, I got some problems when optimizing d,e (linked between all images), even if the solution before was quite good, and his images contain shots from many different angles. I haven't expected an high correlation between p and TrZ though, so this is interesting and should be analyzed in more detail. It might just be that the starting point in the solution space is very far from the global optima. 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 -~----------~----~----~----~------~----~------~--~---
