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position of ar_alvar markers on Baxter robot [closed]

asked 2014-04-28 05:00:58 -0500

lwi gravatar image


I am new to ROS and I try to detect the position of AR alvar markers in a video stream coming from a Baxter robot.

For that I use the following command:

rosrun  ar_track_alvar individualMarkersNoKinect 5 0.1 0.1 /cameras/right_hand_camera/image /cameras/right_hand_camera/camera_info world

As I understood the documentation this should transform the published coordinate frame to the right position in the world coordinate frame.

If I visualize this in RVIZ (topic /visualization_marker) the markers are detected but they do not overlap the markers in the image. In RVIZ they seem to have the right z-coordinate but the x and z coordinate are off. I also tried to specify other frames of the robot like right_gripper, right_wrist, right_hand, world or head. However, the position of the markers does never change regardless what frame I specify.

My question is if I understand the alvar package right and there should be a automatic transformation of the coordinate system so that the printed and the virtual markers overlap?

Also , if there is such a transformation, I would be very thankful for any tipps or ideas where to find the cause of the problem.

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Closed for the following reason the question is answered, right answer was accepted by lwi
close date 2014-04-28 09:32:38

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answered 2014-04-28 09:31:59 -0500

lwi gravatar image

I solved this by setting the camera resolution to 1280x680. After that the library behaved as expected.

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Asked: 2014-04-28 05:00:58 -0500

Seen: 881 times

Last updated: Apr 28 '14