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Hi Pablo,
The new package pose_cov_ops in the mrpt_common stack does exactly what you're looking for.
It includes pose (direct and inverse) composition with a rigorous treatment of uncertainty, even when it's given as a 6x6 covariance matrix in yaw-pitch-roll, which is much harder to implement than e.g. as a 7x7 with unit quaternion representation.
The package is actually a wrapper of functionality in the lib mrpt-base, which has dozens of unit tests regarding uncertainty transformations so it should be quite reliable. Much more of mrpt-base functionality is expected to be wrapped in the future.
Check the package wiki for references to a technical report explaining all the internal equations.
Cheers.
This is a really really interesting package. AFAIK ROS lacked of this functionality. Neither TF, KDL, Bullet nor BFL provide this functionality. Specially interesting is the case of changing a pose to an uncertain frame.
In fact I would like to see TF system based of this uncertainty handling. I think this would be a much more powerful system allowing even a transformation graph instead of a transformation tree thanks to the possibility of a bayesian fussion of two estimation of the same frame.
Pablo: Building a transformation tree is "easy", given you correctly handle covariance transformations. But graphs, which may have loops, are much harder! They become in fact an entire new problem on its own: graph-slam ;-)
Instructions can be found here: https://code.google.com/p/mrpt-ros-pkg/
Asked: 2012-02-15 22:54:15 -0500
Seen: 3,524 times
Last updated: Mar 25 '12
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I talk a bit more about this problem in this post of my blog: http://geus.wordpress.com/2012/02/17/cambiando-el-marco-de-referencia-de-una-distribucion-gaussiana/ . I'm sorry it is in spanish but It may be useful for some people.
You might want to read into "S. Su and C. Lee, “Manipulation and propagation of uncertainty and verification of applicability of actions in assembly tasks,” Systems, Man and Cybernetics, IEEE Transactions on, vol. 22, no. 6, pp. 1376– 1389, 1992."