Using these two library functions:
to create a simple rotation matrix from Euler Angles:
import numpy as np
import SimpleITK as sitk
from scipy.spatial.transform import Rotation
from math import pi
euler_angles = [pi / 10, pi / 18, pi / 36]
sitk_matrix = sitk.Euler3DTransform((0, 0, 0), *euler_angles).GetMatrix()
sitk_matrix = np.array(sitk_matrix).reshape((3,3))
print(np.array_str(sitk_matrix, precision=3, suppress_small=True))
order = 'XYZ' # Different results for any order in ['XYZ','XZY','YZX','YXZ','ZXY','ZYX','xyz','xzy','yzx','yxz','zxy','zyx']
scipy_matrix = Rotation.from_euler(order, euler_angles).as_matrix()
print(np.array_str(scipy_matrix, precision=3, suppress_small=True))
I get two different results:
[[ 0.976 -0.083 0.2 ]
[ 0.139 0.947 -0.288]
[-0.165 0.309 0.937]]
[[ 0.981 -0.086 0.174]
[ 0.136 0.943 -0.304]
[-0.138 0.322 0.937]]
Why? How can I compute the same matrix as SimpleITK using scipy?