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Geometry direction

Open vincentme opened this issue 4 years ago • 2 comments

Hi

I am trying to understanding the geometric direction assumed in this toolbox. The python implementation is used.

Let's take Demo 03: Simple Image as an example.

This is the first slice of the projection. proj1

Diagram shows the geometric definition in the Ander Biguri's Thesis (page 76) Screenshot_20200326_160426

Slice in the 1st, 2nd, and 3rd dimension of the reconstruction image volume, e.g. imgOSSART[25], imgOSSART[:, 25], and imgOSSART[..., 25] respectively. 1 2 3

My confusion comes from here: from the projection image and the diagram of the geometry, the x, y, z direction of the coordinate system seem are parallel with Medial/Lateral, Anterior/Posterior, and Superior/Inferior respectively. In combined with the observation of the slice of the reconstructed volume, the order of the dimension of the volume seems to be organized as [Z, Y, X]. It is a little bit odd for me to have a volume to be organized in this way. In addition, in the function of plotimg, it seems the order is assumed to be [X, Y, Z].

I am not sure if my understanding is correct, so I would like to have your clarification. Thank you!

vincentme avatar Mar 26 '20 21:03 vincentme

@vincentme Your understanding is correct, if you are using the python version.

This is mostly because the python version is not fully finished. We need to change the way computation is done in CUDA, and then change the python to some reasonable axis. When the paper was published, only a MATLAB version existed and the figure is true in MATLAB.

In short: python is still work in progress. Leave this Issue open, so we can tackle it in the future.

AnderBiguri avatar Mar 26 '20 21:03 AnderBiguri

@vincentme Your understanding is correct, if you are using the python version.

This is mostly because the python version is not fully finished. We need to change the way computation is done in CUDA, and then change the python to some reasonable axis. When the paper was published, only a MATLAB version existed and the figure is true in MATLAB.

In short: python is still work in progress. Leave this Issue open, so we can tackle it in the future.

Thank you! I am good as long as this is expected behavior.

vincentme avatar Mar 26 '20 22:03 vincentme