How to understand feature "Shift" in module "Volume Rendering"?

Development
1

Hello,

There are two questions that I was not able to figure out. Please help me. :wink:

  1. I was trying to get the 3D coords of the skin-surface of the back surface from a vertebral MR, to get the posterior-anterior axis given the inferior-superior axis and left-right axis.

Is there a module to help do that?

  1. When showing the volume rendering, the feature “Shift” (as shown in the screenshot below) changed the valid volume. How should I understand the disappeared volume when Shift is enlarged? And how the extra pure-black volume was added when Shift is reduced?
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image1501×898 353 KB

2

It is equivalent with adding/subtracting a constant to voxel values.

What it actually does it shifts volume rendering transfer functions, which you can find in the “Advanced” section.

3

Hi Iassoan,

Thank you for your reply!
It seems that the “Advanced” section is kind of advanced for me. :sweat_smile:

Could you please post some link or tutorial, or even source code about how the feature “Shift” is applied on voxel processing mathematically?

Thank you in advance!

4

Shift is equivalent to adding/subtracting a constant value from the voxel values. You can read more about volume rendering in the VTK Textbook.