[vtkusers] vtkPolydata contour to image

[Sara Rolfe]

Sorry, I just realized there was a typo in the code I sent, please  
look at this version.

Thanks,
Sara

	// Draw contours around the segmented regions
     	vtkSmartPointer<vtkContourFilter> contour =  
vtkSmartPointer<vtkContourFilter>::New();
     	contour->SetInput( vtkImporter->GetOutput() );
    	 contour->SetValue(0, 128); // edges of a binary image with  
values 0,255
	contour->Update();
	
	// get list of points from polydata
	vtkPolyData * polyData = contour->GetOutput();
	const unsigned int numberOfPoints = polyData->GetNumberOfPoints();
	cout << "Numbers of points: " << numberOfPoints << endl;
	vtkPoints * vtkpoints = polyData->GetPoints();

	
	//allocate itk image to be used as a property mask for later region  
merging
	MaskImageType::Pointer propertyMask = MaskImageType::New();	
	propertyMask->SetRegions( inputImage->GetLargestPossibleRegion() );
	propertyMask->SetOrigin( inputImage->GetOrigin() );
	propertyMask->SetSpacing( inputImage->GetSpacing() );
	propertyMask->SetDirection( inputImage->GetDirection() );
	propertyMask->Allocate();
	
	// iterate through image
	double defpoint[3];
	MaskImageType::IndexType index;
	MaskImageType::SpacingType spacing = inputImage->GetSpacing();	
	
	for(unsigned int p =0; p < numberOfPoints; p++)
     {
		vtkpoints->GetPoint( p, defpoint );				// get point in polydata mesh  
of surface
		
		index[0] = defpoint[0]/spacing[0];				// convert polydata index to  
field index
		index[1] = defpoint[1]/spacing[1];
		index[2] = defpoint[2]/spacing[2];
		
		propertyMask->SetPixel( index, 255 );
	}
	

On Mar 12, 2011, at 7:31 AM, Sara Rolfe wrote:

> Hello,
>
> In case it helps to see what I did, I am including the code below.   
> However, I suspect this is not the best approach.
>
> Thanks,
> Sara
>
> 	// Draw contours around the segmented regions
>     	vtkSmartPointer<vtkContourFilter> contour =  
> vtkSmartPointer<vtkContourFilter>::New();
>     	contour->SetInput( vtkImporter->GetOutput() );
>     	contour->SetValue(0, 128); // edges of a binary image with  
> values 0,255
> 	contour->Update();
> 	
> 	// get list of points from polydata
> 	vtkPolyData * polyData = contour->GetOutput();
> 	const unsigned int numberOfPoints = polyData->GetNumberOfCells();
> 	cout << "Numbers of points: " << numberOfPoints << endl;
> 	vtkPoints * vtkpoints = polyData->GetCells();
>
> 	
> 	//allocate itk image to be used as a property mask for later region  
> merging
> 	MaskImageType::Pointer propertyMask = MaskImageType::New();	
> 	propertyMask->SetRegions( inputImage->GetLargestPossibleRegion() );
> 	propertyMask->SetOrigin( inputImage->GetOrigin() );
> 	propertyMask->SetSpacing( inputImage->GetSpacing() );
> 	propertyMask->SetDirection( inputImage->GetDirection() );
> 	propertyMask->Allocate();
> 	
> 	// iterate through image
> 	double defpoint[3];
> 	MaskImageType::IndexType index;
> 	MaskImageType::SpacingType spacing = inputImage->GetSpacing();	
> 	
> 	for(unsigned int p =0; p < numberOfPoints; p++)
>     {
> 		vtkpoints->GetCell( p, defpoint );				// get point in polydata  
> mesh of surface
> 		
> 		index[0] = defpoint[0]/spacing[0];				// convert polydata index to  
> field index
> 		index[1] = defpoint[1]/spacing[1];
> 		index[2] = defpoint[2]/spacing[2];
> 		
> 		propertyMask->SetPixel( index, 255 );
> 	}
>
> On Mar 11, 2011, at 3:42 PM, Sara Rolfe wrote:
>
>> 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
>>
>> <Picture 10.png>
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