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AprilRobotics / apriltag

AprilTag is a visual fiducial system popular for robotics research.
https://april.eecs.umich.edu/software/apriltag
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Geometric interpretation of estimation error #290

Closed afdaniele closed 9 months ago

afdaniele commented 10 months ago

Hi, we are trying to use the pose error computed by the function estimate_tag_pose.

We see values that go from 10e-7 when the detection is qualitatively good to 10e-4 when the detection is in a region of the image that is heavily affected by distortion. What is the unit / geometric interpretation of this error?

Thanks,

mkrogius commented 9 months ago

This will be in the same units you input for tag size and camera focal length, which usually will be meters. For the geometric interpretation see the paper cited on this line: https://github.com/AprilRobotics/apriltag/blob/6fd978cf03b98d6a058e22e5253cc617c7eccd06/apriltag_pose.h#L50

afdaniele commented 9 months ago

We will take a look, thanks for the pointer.