what is denoted by sitk.GetDirection()

, ,
1

I want to understand the interpretation of the array returned by GetDirection in case of MRI image.
(-0.9998157207129488,
0.019196994953562158,
0.0,
-0.019196994953562158,
-0.9998157207129488,
0.0,
0.0,
0.0,
1.0)

Can someone please help me understand this?

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2

Hello @prms,
The direction, often referred to as direction cosine matrix, is the direction of the image axis in row major order. In ITK/SimpleITK the axes are not necessarily orthonormal (identity matrix) which is the case with your data. This has to do with the fundamental idea in ITK/SimpleITK that an image is a spatial object. More on this in the SimpleITK fundamental concepts page.

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3

thanks a lot :slight_smile: