Error Metrics

[Yaara1]

Hello,
I wanted to ask how is the rotation error and translation error (shown in the paper in figures 3 and 4) calculated.
In the code I have seen calculation of the mean error in the twist parameters (norm of the whole vector of twist parameters, dm) and I have also seen in result_stat.py a calculation of the error of the rotation part of the twist error vector and translation part, separately (ep and ev for translation and also ew for the error in rotation twist parameters). But it is not clear to me what is the specific metric used in the paper. Especially how to get to the rotation error metric in degrees units.

Also, why do you transform the twist parameters to rotation matrices and than back again to twist parameters?

Thank you in advance.