I tried calculating Straintensor with ITKStrain Module http://insight-journal.org/browse/publication/984 from a 2D DisplacementField (256,256,2). The output is a SymmetricSecondRankTensor. I converted to numpy array and get an (256,256,3)- shaped array.
My question concerns the indexing. Due to symmetry reasons a 2D-SymmetricSecondRankTensor would look like:
hence only one “b” is stored (leading to dimension 3 in numpy array). But the question remains, which index (especially in numpy) represents which value. I read the Documentation of ITK::SymmetricSecondRankTensor, but unfortunatly i did not understand it
Can anyone help me?
Thanks in advance.