VTK中vtkImageLuminance類提供了彩色影象變換到灰度影象的方法，該類的使用比較簡單，可以通過以下程式碼實現：

int main()
{
    vtkSmartPointer<vtkBMPReader> reader = vtkSmartPointer<vtkBMPReader>::New();
    const char* filename = "D:\\Color2GrayTest.bmp";
    reader->SetFileName(filename);

    vtkSmartPointer<vtkImageLuminance> luminanceFliter = vtkSmartPointer<vtkImageLuminance>::New
 
();
    luminanceFliter->SetInputConnection(reader->GetOutputPort());
    luminanceFliter->Update(); 

    vtkSmartPointer<vtkImageActor> originActor = vtkSmartPointer<vtkImageActor>::New();
    originActor->GetMapper()->SetInputConnection(reader->GetOutputPort());
    vtkSmartPointer<vtkImageActor> resultActor = vtkSmartPointer<vtkImageActor>::New
 
();
    resultActor->GetMapper()->SetInputConnection(luminanceFliter->GetOutputPort());

    double originViewport[4] = { 0.0,0.0,0.5,1.0 };
    double resultViewport[4] = { 0.5,0.0,1.0,1.0 };

    vtkSmartPointer<vtkRenderer> originRender = vtkSmartPointer<vtkRenderer>::New();
    originRender->SetViewport
 
(originViewport);
    originRender->AddActor(originActor);
    originRender->SetBackground(1.0, 1.0, 1.0);
    originRender->ResetCamera();

    vtkSmartPointer<vtkRenderer> resultRender = vtkSmartPointer<vtkRenderer>::New();
    resultRender->SetViewport(resultViewport);
    resultRender->AddActor(resultActor);
    resultRender->SetBackground(1.0, 1.0, 1.0);
    resultRender->ResetCamera();

    vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
    renderWindow->AddRenderer(originRender);
    renderWindow->AddRenderer(resultRender);

    vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = vtkSmartPointer<vtkRenderWindowInteractor>::New();
    renderWindow->SetInteractor(renderWindowInteractor);
    renderWindow->SetSize(800, 600);
    renderWindow->SetWindowName("Color2GrayImageTest");
    renderWindow->Render();

    renderWindowInteractor->Start();

    return EXIT_SUCCESS;
}

執行結果：