OpenCV: how to get yaw, roll, pitch from POSIT (solvePnP) rotation matrix

Question

what is the algorithm used to calculate the yaw(z axis), roll(x axis) and pitch(y axis) from the 3*3 rotation matrix generated by cvPOSIT.

Answer 1

Use cv::RQDecomp3x3(). "It optionally returns three rotation matrices, one for each axis, and the three Euler angles in degrees (as the return value)".
Note that the results are degrees.