Re: [PCL-users] Segment planes perpendicular to axis Z
|This message is part of the following thread:|
|the complete thread tree sorted by date|
|Aaron O'Toole <airuno2L@gmail.com> at|
|Suat Gedikli at|
> I believe I fixed this in trunk and all branches. Can you please give it a try again?
> Thank you in advance.
> Cheers, > Radu. > -- > Point Cloud Library (PCL) - http://pointclouds.org
> On 07/22/2011 07:01 AM, Ruben Ares wrote: > > I've tried with a point cloud with 100 points, all of them with z=1. > > > > The next code (with eps angle corrected) doesn't find any plane.
> > > > g.setModelType (pcl::SACMODEL_PERPENDICULAR_PLANE); > > seg.setMethodType (pcl::SAC_RANSAC); > > seg.setMaxIterations(1000); > > seg.setDistanceThreshold (0.1); > > seg.setAxis(Eigen::Vector3f(0,0,1)); > > seg.setEpsAngle (0.1);
> > > > I'm going to create an issue on the tracker.
> > > > Thanks for the help. > > > Date: Wed, 20 Jul 2011 14:46:45 -0700 > > > From: firstname.lastname@example.org <mailto:email@example.com> > > > To: firstname.lastname@example.org <mailto:email@example.com> > > > CC: firstname.lastname@example.org <mailto:email@example.com> > > > Subject: Re: [PCL-users] Segment planes perpendicular to axis Z
> > > > > > Ruben,
> > >
> > >
> > > > > > On 07/20/2011 02:26 PM, Ruben Ares wrote: > > > > Are there any restrictions in the segmentation module about the coordinate system? I'm only need planes > > perpendicular to > > > > my Z-axis and I don't understad why the coordinate system must be relevant.
> > > > > > Nope, there are no restrictions. Ok, so you want planes perpendicular to your camera's Z. That's easy.
> > > > > > > The scene has that kind of planes but the next code doesn't find any of them.
> > > > > > > > seg.setModelType (pcl::SACMODEL_PERPENDICULAR_PLANE); > > > > seg.setMethodType (pcl::SAC_RANSAC); > > > > seg.setMaxIterations(1000); > > > > seg.setDistanceThreshold (0.05); > > > > seg.setAxis(Eigen::Vector3f(0,0,1)); > > > > seg.setEpsAngle (0);
> > > > > > I think the last call might be the reason for that. You specify an absolute threshold of "0" radians, which > means you > > > want the plane to be perfect. We seem to have introduced a condition that says that the angle has to be larger > than 0 > > > here (check sac_model_perpendicular_plane.hpp, line 85 in trunk), which could be both a bug and a feature :) > (meaning > > > that we're flexible with respect to changing this condition).
> > > > > > As far as I remember the reason for this check is that we need a bit of wiggle room for the sample consensus > methods in > > > terms of getting their samples, otherwise we risk at spending more time in the loop (overconstraining the > system). This > > > should not affect the end results, meaning that if your plane is perfectly perpendicular you will still get it. > The only > > > time this assumption would break is if you would have 2 planes within that tolerance threshold with the exact > number of > > > points, and for some reason you want to differentiate between them.
> > > > > > So basically you need so specify a small tolerance (0.01 radians is good enough if you know for a fact that > your plane's > > > equation is perfectly perpendicular to Z) in order for this to kick in. I just updated the documentation to > point this > > > thing. Sorry for not mentioning this earlier.
> > > > > > If you still have problems with this, can you please create an issue on our tracker > (http://dev.pointclouds.org) with a > > > simple dataset and a minimal code example so we can reproduce the error and try to fix it? Thanks.
> > > > > > Cheers, > > > Radu.
> > > > _______________________________________________ > > PCLfirstname.lastname@example.org <mailto:PCLemail@example.com> / http://pointclouds.org > > https://code.ros.org/mailman/listinfo/pcl-users > _______________________________________________ > PCLfirstname.lastname@example.org <mailto:PCLemail@example.com> / http://pointclouds.org > https://code.ros.org/mailman/listinfo/pcl-users
|This message was posted to the following mailing lists:|
Mailing List Info | Nearby Messages
|Re: [PCL-users] Segment planes perpendicular to axis Z||Re: [PCL-users] Segment planes perpendicular to axis Z|
|code.ros.org list archives administrated by ros.org||Lurker (version 2.3)|