[vtkusers] Volume-Splatting-Problem with images

[Matthias Mucha]

Dear List,

I work with Realtime-2D-Ultrasound-Images which I get from a queue (the image- and tracking-data are stored in a queue which will be updated every 30 ms (30 FPS)). After I transform the images with tracking-data I store the pixel (with its position as vnl-vectors) and the scalars in a vtkPolyData-object. What I now want to do is to build a volume in realtime out of the vtkPolyData-object . So I played around with the vtkGaussianSplatter but I can't fasten it for realtime-reconstruction (it is very slow for images with a dimension of 765x576). 
Also the resolution of the volume is very bad due to the low sample-dimension. Do I miss something when I initialize the vtkGaussianSplatter? Or supplies VTK another solution for such a problem? 

Here is my code for the reconstruction:

for(/*each image (30) in the queue){
/*... get the image and transform them*/
//after transformation
//get the VTK-Image-data out of the MITK-Image
vtkImageData* imageData = m_MITKSlice->GetVtkImageData();


int* dims = imageData->GetDimensions();		//get image-dimensions
mitk::Point3D index = mitk::Point3D();
mitk::Point3D pixelPos = mitk::Point3D();
//iterate through each pixel in the 2D-image to get the color and the position
for (int z = 0; z < dims[2]; z++){
  for (int y = 0; y < dims[1]; y++){
   for (int x = 0; x < dims[0]; x++){
	index = mitk::Point3D();
	pixelPos = mitk::Point3D();
	index.GetVnlVector()[0] = x;
	index.GetVnlVector()[1] = y; 
	index.GetVnlVector()[2] = z;
	
//get the pixel-position					m_MITKSlice->GetGeometry()->IndexToWorld(index, pixelPos); 

unsigned char* pixel = static_cast<unsigned char*>(imageData->GetScalarPointer(x, y, z));
						pixelValues->InsertNextValue(*pixel);
						points->InsertNextPoint(pixelPos.GetVnlVector()[0], pixelPos.GetVnlVector()[1], pixelPos.GetVnlVector()[2]);
    }
   }
  }
}

//set the point-Array which stores all slices
pointsPolydata->SetPoints(points);	


//convert the points to vertices
vtkSmartPointer<vtkVertexGlyphFilter> vertexFilter = 
vtkSmartPointer<vtkVertexGlyphFilter>::New();
		vertexFilter->SetInputConnection(pointsPolydata->GetProducerPort());
vertexFilter->Update();

volumeGrid->ShallowCopy(vertexFilter->GetOutput());
volumeGrid->GetPointData()->SetScalars(pixelValues);

//splatt the polydata into a volume
splatter->SetInput(volumeGrid);
splatter->SetRadius(0.05);

//it take hours to build the volume if the sample-dimension is set to a //high value
splatter->SetSampleDimensions(80,80,80); 
splatter->SetAccumulationModeToMin();
splatter->SetExponentFactor(-10);
splatter->SetScaleFactor(1);
splatter->NormalWarpingOn();

splatter->Update();
vtkImageData* outVolume = splatter->GetOutput();

Best regards!

Matthias Mucha
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