[vtkusers] Image Blob as polydata.

[Cory Quammen]

Hi Tariq,

It would be easier to diagnose with a full code listing that includes the
class instantiation so we know what classes you are using. As it is, I can
guess that you are using vtkImageThreshold instead of vtkThreshold.
vtkImageThreshold will not clip away the cells you don't want - you need to
use vtkThreshold to do that. vtkImageThreshold will produce a vtkImageData
output where the voxel values may change, but it won't clip away any data.

On a side note, I recommend that you do the following to set up your
pipeline:

vtkJPEGReader* jpgRead = vtkJPEGReader::New();
jpgRead->SetFileName(y.c_str());

vtkThresholdFilter* thresholder = vtkThresholdFilter::New();
threshold->SetInputConnection(jpgRead->GetOutputPort());

vtkDataSetSurfaceFilter* dataSurface = vtkDataSetSurfaceFilter::New();
dataSurface->SetInputConnection(threshold->GetOutputPort());

vtkPolyDataMapper* pMapper = vtkPolyDataMapper::New();
pMapper->SetInputConnection(dataSurface->GetOutputPort());
...

Note that you do not need to explicitly update each filter - the pipeline
will figure out when each filter needs to be updated.

Thanks,
Cory

On Fri, Oct 23, 2015 at 9:09 PM, tariq <tdinar at gmail.com> wrote:

> hi Cory,
> this is the code I wrote
>     jpgRead->SetFileName(y.c_str());
>     jpgRead->Update();
>     imageData = jpgRead->GetOutput();
>     imageThreshold->SetInputData(imageData);
>     unsigned char lower = 250;
>     unsigned char upper = 255;
>     imageThreshold->ThresholdBetween(lower, upper);
>     imageThreshold->ReplaceInOn();
>     imageThreshold->SetInValue(255);
>     imageThreshold->Update();
>     dataSurface->DataSetExecute(imageThreshold->GetOutput(), pData);
>     pMapper->SetInputData(pData);
>     outputtActor->SetMapper(pMapper);
>     outputtActor->GetProperty()->SetRepresentationToWireframe();
>     inputActor->SetInputData(imageData);
>
>  rendering input on the left and output on the right (wireframe). All the
> cells (black or white are propagated to the output). how can I get hold of
> the black cells only? I would settle for that, instead of the boundary of
> the black cells region.
> I appreciate the help.
> <
> http://vtk.1045678.n5.nabble.com/file/n5734545/Screen_Shot_2015-10-23_at_6.png
> >
> Thanks.
> T.
>
>
>
>
>
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-- 
Cory Quammen
R&D Engineer
Kitware, Inc.
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