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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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add 3x3 rotation matrix to quaternion function #265

Open chobitsfan opened 1 year ago

chobitsfan commented 1 year ago

In https://github.com/AprilRobotics/apriltag/issues/90#issuecomment-656802651, @mkrogius suggests using doubles_mat_to_quat to get a quaternion from the matrix. However, rotation matrix in apriltag_pose_t is a 3x3 matrix and doubles_mat_to_quat expects a 4x4 matrix. It would be easier to use if we have a doubles_mat33_to_quat.

christian-rauch commented 1 year ago

Thank you for the patch. Where is this new function used? I cannot find references to doubles_mat_to_quat. Can you provide more details on why this new function is required?

chobitsfan commented 1 year ago

Hi @christian-rauch Thank you for reviewing

I cannot find references to doubles_mat_to_quat

Yes. doubles_mat_to_quat is defined but never used. But in https://github.com/AprilRobotics/apriltag/issues/90, @mkrogius suggests it can be used (with doubles_quat_to_rpy) to obtain euler angles from apriltag_pose_t. I found it is quite useful. However, rotation matrix in apriltag_pose_t is a 3x3 matrix and doubles_mat_to_quat expects a 4x4 matrix.