[vtkusers] Help accessing results from Sobel3D

[David Doria]

On Fri, Mar 30, 2012 at 6:48 AM, Paulo Neves <paulo.alex.neves at gmail.com> wrote:
> Dear all,
>
> I am trying to obtain results of Sobel 3D over a 3D dataset of DICOM images.
>
> DICOM images are correctly imported through GDCM, and a Ray Casting Volume
> Rendering shows that everything is ok with this part.
>
> I am using vtkSobel3D to calculate sobel filter by setting the input
> connection to the output of the reader.
>
> Up to this everything seems to be fine. However, now I needed to get to the
> values themselves, which I hope results in a 3 (Gx, Gy and Gz) sober
> components, each with 3 coordinates (x, y, z). This comes from my analogy
> that Sobel 2D produces Gx and Gy, both 2D "images".
>
> I found out an example with Sobel3D in
> here: http://www.vtk.org/Wiki/VTK/Examples/Cxx/Broken/Images/ImageSobel3D
>
> However, I only obtain a planar image from the x and y components (no z
> component in the example, since it is only a 2D image as source).
>
> My question is, since I have 3D Gx, Gy and Gz components, how can I access
> them?
>
> Any help would be much appreciated.
>
> Best regards,

That example is in the "Broken" category, so I wouldn't trust it :).
However, it is creating a 3D image as input. It looks to me like you'd
just need to add a new extract filter with:

extractZFilter->SetComponents(2);

It would be great if you could fix this example along the way!

David