def structure_tensor_eigvals(Axx, Axy, Ayy):
 return _image_orthogonal_matrix22_eigvals(Axx, Axy, Ayy)

def structure_tensor_eigvals ( Axx , Axy , Ayy ) : return _image_orthogonal_matrix22_eigvals ( Axx , Axy , Ayy )
compute eigen values of structure tensor .