Hi Jerry, due to small-scale noise, the orientation of the tangent to a centerline can be quite erratic compared to what one expects by looking at the same centerline at a distance. More so, centerlines might be irregularly sampled, and you might find yourself taking finite differences on nearly-coincident points, and this is what I think is happening in your case.
The solution needs two steps: resample centerlines and smooth them. Here's how you do it: vmtkcenterlineresampling -ifile centerlines.vtp -length 1.0 --pipe vmtkcenterlinesmoothing -iterations 100 -ofile centerlines_rs_sm.vtp where -length is the length of the output line segments or, if you prefer, the distance between samples in the resampled centerline; - iterations controls how much smoothing you're imposing on the centerlines. Note that just the resampling might actually be sufficient, without the smoothing, just play with it and see what happens. Best regards Luca On Dec 22, 2011, at 3:49 AM, Lingfeng Zhuang wrote: > Hi, > > I am using centerline generated by vmtk as the path of camera in my Airway > Endoscopy program. > > centerline[n] as camera position, centerline[n+1] as focal position. I meet a > problem, the camera direction sometimes has a great change when moving from > point n to point n+1. > > In those cases, it is likely that, at point n, use can see next airway hole > nearby. But at point n + 1, use can only see the airway way due to big > direction change. > > Any advice will be appreciated. > > Best regards, > > Jerry > ------------------------------------------------------------------------------ > Write once. Port to many. > Get the SDK and tools to simplify cross-platform app development. Create > new or port existing apps to sell to consumers worldwide. Explore the > Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join > http://p.sf.net/sfu/intel-appdev_______________________________________________ > vmtk-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/vmtk-users ------------------------------------------------------------------------------ Write once. Port to many. Get the SDK and tools to simplify cross-platform app development. Create new or port existing apps to sell to consumers worldwide. Explore the Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join http://p.sf.net/sfu/intel-appdev _______________________________________________ vmtk-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/vmtk-users
