I think its a known problem about artoolkit .. this link Robust Pose estimation from planar target mentions some of those.. The artoolkitplus has a robust pose estimate api which "reduces" this problem. However, I did see this issue to a smaller extent even with rpp. I am not sure if I was using it the wrong way though. Eohan On Mon, Nov 8, 2010 at 10:47 AM, Ivan Dryanovski wrote: > Steven, > > I'm not sure if this is exactly the problem you are observing, but I > have noticed a similar behavior from ARToolkit before. When the camera > is nearly perpendicular to the marker, and the marker is in the center > of the image, there occurs a singularity. Let's say the angle between > the marker normal and the optical axis is 1 degree - ARToolkit will > arbitrary flip between +1 and -1 degrees. If you make the angle > bigger, the orientation of the marker becomes less ambiguous, and the > error diminishes. > > Ivan Dryanovski > > On Mon, Nov 8, 2010 at 9:00 AM, Herman Bruyninckx > wrote: > > On Mon, 8 Nov 2010, Steven Bellens wrote: > > > >> 2010/11/8 Steven Bellens : > >>> Hi, > >>> > >>> I'm experimenting a bit with the ar_pose package. I'm using a single > >>> fixed camera to track a moving marker. To verify the estimation > >>> accuracy, I just leave the marker fixed and I've plotted position and > >>> orientation estimates. The position estimates are pretty much > >>> constant, but the orientation estimates are oscilating a lot (see > >>> appendix), and apparently always between two values. Is this because > >>> of the bad capability to estimate that orientation or can this be > >>> caused by the environment conditions (light - set-up - distance to > >>> marker)? > >> > >> For clarity, plotted are the 4 components of a unit quaternion. > > > > So...? What does a jump of "0.1" quaternion units mean? And is this > meaning > > the same for each of the four components? > > > > The answer to this last question is probably "no", hence...? > > > > Herman > > _______________________________________________ > > ros-users mailing list > > ros-users@code.ros.org > > https://code.ros.org/mailman/listinfo/ros-users > > > _______________________________________________ > ros-users mailing list > ros-users@code.ros.org > https://code.ros.org/mailman/listinfo/ros-users >