I have calculated the yaw,pitch and roll of the head from euler angles as follows in my code.
eulerangles = rotationMatrixToEulerAngles(rotation_matrix)
yaw = eulerangles[1]
pitch = eulerangles[0]
roll = eulerangles[2]
How do I use these values to find the angle from the axis? For instance if the head is rotated 360 degree, how do I know the angle of rotation from the center?