[vtkusers] Using vtkProbeFilter to sample values of NIFTI volume onto surface

[Sujin Philip]

Hi Michael,

In this case, for each vertex in the surface mesh, the filter finds the
voxel within which the vertex falls and interpolates the points values of
the 8 points of the voxel on to the vertex. The tolerance is used for
dealing with floating point errors. It specifies the tolerance to use when
a vertex is near the boundary of a cell to determine if it should be
considered to be inside the cell.

Thanks
Sujin


On Sat, Feb 23, 2019 at 6:59 PM Michael Jordan <mjordan080013 at gmail.com>
wrote:

> Hi,
>
> i have a fMRI NIFTI volume whereby each voxel value corresponds to a
> statistical value indicating the activation. I am using the vtkProbeFilter
> to show the activation on the
> corresponding brain surface. The results looks pretty good but I would
> like to understand what is really going on when using the vtkProbeFilter.
>
> Assumed that I specify a tolerance value of 10.0 <+49100>, how the filter
> determines the corresponding scalar value for a certain surface vertex?
> Is the filter simply assigning the value of the closest voxel to the
> vertex? Or is the filter averaging all values within the specified
> tolerance?
>
> Thank you!
>
> Regards, Michael
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