Based on these Slicer Wiki and ITK wiki I think the direction matrix used in the code can also be called LPS orientation, not just RAI, it is matter of using "to" or "from" concepts to represents the letter:
# LPS: Right to (L)eft, Antiror to (P)ostiror, Inferor to (S)superior
# RAI: (R)ight to Left, (A)ntiror to Postiror, (I)nferor to Superior
m = itk.GetMatrixFromArray(np.array([[1, 0, 0], [0, 1, 0], [0, 0, 1]], np.float64))
I think since all output images have the same orientation probably the naming does not matter.
Based on these Slicer Wiki and ITK wiki I think the direction matrix used in the code can also be called LPS orientation, not just RAI, it is matter of using "to" or "from" concepts to represents the letter:
I think since all output images have the same orientation probably the naming does not matter.