[vtkusers] Smooth label-map volume rendering

[Bertram Sabrowsky-Hirsch]

Hi all,

I am working with volume data before and after a classification algorithm.
The input volume has ushort intensity values, the output volume is a label-map where the values indicate each voxels class/label (background=0, vessel=1, aneurysm=2, ...).

I am visualizing the input volume with a opacity transfer function that simulates a threshold filter (e.g. control points: 799=0.0, 800=1.0) and the result is a nice and smooth visualization of the volume.

However, the output volume has this blocky Minecraft style effect. The opacity transfer function has the control points: 0=0.0, 1=1.0 and I use the color transfer function to distinguish the classes/labels.
Is there a way to visualize the output volume in a similar way as the input volume? I considered generating iso-surface meshes and smooth those, but this is not really an option. I also don't really understand why this is an issue because the
Input volume is also rendered with a distance of 1 between the two opacity thresholds. Are the volumes handled differently by vtk and how?

Input volume:
[cid:image001.jpg at 01D3FE45.7E817C10]

Output volume:
[cid:image006.jpg at 01D3FE45.7E817C10]

Kind regards,
Bertram
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