[vtkusers] vtkPolydata contour to image

[Jérôme]

The first solution may be implemented through this pipeline:
vtkImageData (your binary volume, from a reader or another producer)
-> vtkImageGradient -> vtkImageMagnitude

The second one with erosion would be:
vtkImageData  --> vtkImageDilateErode3D --->  vtkImageMathematics
(SetOperationToSubstract)
                      ------------------------------------------>

Though I never implemented such pipelines, it should do the trick. Are
you sure there are no example on the VTK wiki?

Best regards,
Jerome

2011/3/13 Sara Rolfe <smrolfe at u.washington.edu>:
> Thanks Jerome.  I actually started with a binary volume and converted to the
> polydata contour.  Sounds like this step may be unnecessary.
> Can anyone point me to an example of getting an image data contour from a
> filled binary volume?  I've checked the email archives and haven't seen
> anything yet.
> Thanks,
> Sara
> On Mar 12, 2011, at 8:55 AM, Jérôme wrote:
>
> Hi Sara,
> In my mind, theproblem is that your polydata sampling does not match the
> image sampling. If you managed to get a filled binary volume from your
> polydata surface, then you can try to compute the gradient of this image.
> Another solution is to substract the binary volume from a dilated version of
> the binary volume: the output will contain only the contour voxels.
>
> Note, they are a lot of other solutions, but these one may be implemented
> thanks to native VTK filters.
>
> HTH,
> Jerome
>
>
> 2011/3/12 Sara Rolfe <smrolfe at u.washington.edu>
>>
>> Hello,
>> I have a vtkPolydata contour that I'd like to convert into image data.
>>  This is similar to the example here:
>>
>> VTK/Examples/Cxx/PolyData/PolyDataContourToImageData
>>
>> except that I don't want the image contour to be filled.  I thought that I
>> could get around this by using polyData->GetPoints, iterating through the
>> point list, converting to an ITK image index, and assigning the image data
>> value.  However, I get the ridge artifact shown in the image I've attached.
>>
>> Please let me know if you have any ideas on the optimal method to solve
>> this problem.
>> Thanks,
>> Sara
>>
>>
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