[vtkusers] Clipping image data with polygon data.

[David Gobbi]

The "dataToStencil" needs more information than just the spacing.
Most importantly, it needs to know what the size of the image is.  The
best thing to do is the following, so that "PolyDataToImageStencil"
will build a stencil object the same size as the image:

dataToStencil->SetInformationInput(bmpReader->GetOutput());

An alternative is to set the OutputSpacing, OutputOrigin, and
OutputWholeExtent of vtkPolyDataToImageStencil manually.

   David


On Mon, Jan 18, 2010 at 9:43 AM, superzz <jxdw_zlf at yahoo.com.cn> wrote:
>
>            vtkMarchingCubes *_skinExtractor = vtkMarchingCubes::New();
>            _skinExtractor->SetInput(bmpreader->GetOutput());
>            _skinExtractor->SetValue(0, 15);
>
>            vtkStripper *_skinStripper = vtkStripper::New();
>            _skinStripper->SetInput(_skinExtractor->GetOutput());
>
>            vtkPolyDataToImageStencil *dataToStencil =
> vtkPolyDataToImageStencil::New();
>            dataToStencil->SetInput(_skinStripper->GetOutput());
>            dataToStencil->SetOutputSpacing(bmpreader->GetDataSpacing());
>
>            vtkImageStencil *_vtkImageStencil = vtkImageStencil::New();
>            _vtkImageStencil->SetInput(bmpreader->GetOutput());
>            _vtkImageStencil->SetStencil(dataToStencil->GetOutput());
>            _vtkImageStencil->ReverseStencilOn();
>            _vtkImageStencil->SetBackgroundValue(50000);
>
>            _vtkImageStencil->Update();
>
> The last line _vtkImageStencil->Update() never return.
>
> Thanks
>
> superZZ
>
>
> David Gobbi-3 wrote:
>>
>> Please provide a few lines of code, so that I can get an idea about
>> what might be going wrong.
>>
>>    David
>>
>>
>> On Sun, Jan 17, 2010 at 9:55 PM, superzz <jxdw_zlf at yahoo.com.cn> wrote:
>>>
>>> Hello David Gobbi
>>> Thank you for your response.
>>> The example works fine. I can see the result in ImageViewer. I want to
>>> export stencil image to raw file now. However, if I call
>>> imageStencil.Update() manually, Update() never returns. Why this happens?
>>>
>>> Thanks
>>>
>>> superZZ
>>>
>>>
>>> David Gobbi-3 wrote:
>>>>
>>>> Hi SuperZZ,
>>>>
>>>> One way that I've done this is with vtkImplicitSelectionLoop, which is
>>>> a vtkImplicitFunction that takes a vtkPoints list that defines a
>>>> polygon.  Then vtkImplicitFunctionToImageStencil can create an image
>>>> stencil, and vtkImageStencil can apply the stencil to the image and
>>>> black out everything outside the polygon.
>>>>
>>>> There are two simple testing examples for stenciling images (both of
>>>> these examples are for 3D images and 3D selection regions, though):
>>>> VTK/Imaging/Testing/Tcl/TestStencilWithFunction.tcl
>>>> VTK/Hybrid/Testing/Tcl/TestImageStencilWithPolydata.tcl
>>>>
>>>> It's probably also possible to use vtkProbeFilter to create a "mask"
>>>> image from your polygon.
>>>>
>>>>    David
>>>>
>>>>
>>>> On Fri, Jan 15, 2010 at 2:46 AM, superzz <jxdw_zlf at yahoo.com.cn> wrote:
>>>>>
>>>>> Hello
>>>>> I wanna know does VTK support clipping image data with specified
>>>>> polygon
>>>>> data.
>>>>>
>>>>> I am developping a segmentation program. What I want to implement is,
>>>>> first
>>>>> user pick some connected polygons, then the program keeps the regions
>>>>> of
>>>>> image data covered by picked polygons. Erase other regions of image
>>>>> data
>>>>> to
>>>>> black.
>>>>>
>>>>> Thanks!
>>>>>
>>>>> superZZ
>>>>> --
>>>>> View this message in context:
>>>>> http://old.nabble.com/Clipping-image-data-with-polygon-data.-tp27173364p27173364.html
>>>>> Sent from the VTK - Users mailing list archive at Nabble.com.
>>>>>
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>>>
>>> --
>>> View this message in context:
>>> http://old.nabble.com/Clipping-image-data-with-polygon-data.-tp27173364p27206195.html
>>> Sent from the VTK - Users mailing list archive at Nabble.com.
>>>
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>
> --
> View this message in context: http://old.nabble.com/Clipping-image-data-with-polygon-data.-tp27173364p27213200.html
> Sent from the VTK - Users mailing list archive at Nabble.com.
>
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html
>
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>
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