|ARToolKit||Mailing List Archive|
|From:||"DEBADEEPTA DEY" <3dey.dce@g ........>||Received:||Dec 19, 2006|
|Subject:||Error minimization for Localization using ARToolkit.|
I am currently trying to use ARToolkit markers in an indoor environment for robot localization. I do not have access to the robot motion model or inertial sensors and hence Kalman filtering is not an option. I have fiducials that are approx 30cm*30cm in size and the goal is to localize to cm level accuracy from a large distance. One information that I do have is the ground truth relative fiducial transformations and also the transformation of each fiducial wrt the global origin. If I just invert the transformation matrices to each camera I get a very bad location estimate since all errors get magnified. I am looking for pointers as to how looking at multiple markers in the same frame and knowing ground truth transformations between them can be used for achieving more accurate localization.(Maybe some sort of nonlinear error minimisation like Gauss-Newton?) -- Debadeepta Dey, Research Intern, Hitech Robotics Systemz, India.
|From:||CLG <admin@c .............>||Received:||Dec 21, 2006|
|To||ARtoolkit forum <artoolkit@h ..................>|
|Subject:||Re: Error minimization for Localization using ARToolkit.|
(Maybe some sort of nonlinear error minimisation like > Gauss-Newton?) Yes, multimarker nonlinear optimization improve accuracy and stability a lot in my experience. I don't think you can do it using ARToolkit, though I may be wrong here - I'm not using ARToolkit myself. You can get even better accuracy if some more information about markers shape is used (proportions, feature points inside etc) and by using specifically designed markers, not just plain squares. Exact method should depend on requierment, the markers used, camera, camera stability, resolution etc. You can use MXRToolkit, which have in-built non-linear optimization, or just write your own, latter usually better if you have some special requirements. I myself can't use MXRToolkit - it's too calculation heavy, and I'm writing code for camera-phone.