[vtkusers] Displaying DICOM images in grayscale

[Alexis Cheng]

Dear all,

I'm having some trouble displaying DICOM images read in with vtkDICOMImageReader in grayscale. I was able to display it in grayscale using imageViewer2 as per the example, but not with this texture, mapper, actor, renderer setup. My pipeline looks like this:

/////

for (int i = 0; i < inputFileVector.size(); i++)
    {
        // Read all the DICOM files in the specified directory.
        vtkSmartPointer<vtkDICOMImageReader> reader = vtkSmartPointer<vtkDICOMImageReader>::New();
        reader->SetFileName(inputFileVector.at(i).c_str());
        reader->Update();

        vtkSmartPointer<vtkImageData> dicomImage = vtkSmartPointer<vtkImageData>::New();
        dicomImage = reader->GetOutput();

        imageSet.push_back(dicomImage);
    }

planeSource->SetCenter(center.x, center.y, 0.0);
    planeSource->SetNormal(0.0, 0.0, 1.0);
    planeSource->Update();

vtkSmartPointer<vtkImageData> image = imageSet.at((int)getSliceNum());

    texture->SetInput(image);
    texturePlane->SetInputConnection(planeSource->GetOutputPort());
    mapper->SetInputConnection(texturePlane->GetOutputPort());

    imageActor->SetMapper(mapper);
    imageActor->SetTexture(texture);

renderer->AddActor(imageActor);
renderWindow->Render();

/////

The result is that the DICOM image is being displayed in RGB colours. From my searches online, it sounds like I need to apply a lookup table that will convert RGB into luminance, but is that the only way? If imageviewer2 can display it in grayscale without a lookup table, then I would imagine this could do so as well. Thank you in advance for your attention.

Regards,
Alexis Cheng
Computer Science
Johns Hopkins University
 		 	   		  
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