# MedicalDemo1

VTKExamples/Cxx/Medical/MedicalDemo1

### Description

The skin extracted from a CT dataset of the head.

usage

MedicalDemo1 FullHead.mhd

Info

The example uses FullHead.mhd which references FullHead.raw.gz.

Note

This original source code for this example is here.

Info

See Figure 12-2 in Chapter 12 the VTK Textbook.

Other Languages

See (Python)

### Code

MedicalDemo1.cxx

    // Derived from VTK/Examples/Cxx/Medical1.cxx
    // This example reads a volume dataset, extracts an isosurface that
    // represents the skin and displays it.
    //

    #include <vtkActor.h>
    #include <vtkCamera.h>
    #include <vtkMarchingCubes.h>
    #include <vtkMetaImageReader.h>
    #include <vtkNamedColors.h>
    #include <vtkOutlineFilter.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkSmartPointer.h>

    #include <array>

    int main (int argc, char *argv[])
    {
      if (argc < 2)
      {
        cout << "Usage: " << argv[0] << " file.mhd" << endl;
        return EXIT_FAILURE;
      }

      vtkSmartPointer<vtkNamedColors> colors =
        vtkSmartPointer<vtkNamedColors>::New();

      std::array<unsigned char , 4> skinColor{{255, 125, 64}};
        colors->SetColor("SkinColor", skinColor.data());
      std::array<unsigned char , 4> bkg{{51, 77, 102, 255}};
        colors->SetColor("BkgColor", bkg.data());

      // Create the renderer, the render window, and the interactor. The renderer
      // draws into the render window, the interactor enables mouse- and
      // keyboard-based interaction with the data within the render window.
      //
      vtkSmartPointer<vtkRenderer> aRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renWin =
        vtkSmartPointer<vtkRenderWindow>::New();
      renWin->AddRenderer(aRenderer);

      vtkSmartPointer<vtkRenderWindowInteractor> iren =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      iren->SetRenderWindow(renWin);

      vtkSmartPointer<vtkMetaImageReader> reader =
        vtkSmartPointer<vtkMetaImageReader>::New();
      reader->SetFileName (argv[1]);

      // An isosurface, or contour value of 500 is known to correspond to the
      // skin of the patient.
      vtkSmartPointer<vtkMarchingCubes> skinExtractor =
        vtkSmartPointer<vtkMarchingCubes>::New();
      skinExtractor->SetInputConnection(reader->GetOutputPort());
      skinExtractor->SetValue(0, 500);

      vtkSmartPointer<vtkPolyDataMapper> skinMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      skinMapper->SetInputConnection(skinExtractor->GetOutputPort());
      skinMapper->ScalarVisibilityOff();

      vtkSmartPointer<vtkActor> skin =
        vtkSmartPointer<vtkActor>::New();
      skin->SetMapper(skinMapper);
      skin->GetProperty()->SetDiffuseColor(colors->GetColor3d("SkinColor").GetData());

      // An outline provides context around the data.
      //
      vtkSmartPointer<vtkOutlineFilter> outlineData =
        vtkSmartPointer<vtkOutlineFilter>::New();
      outlineData->SetInputConnection(reader->GetOutputPort());

      vtkSmartPointer<vtkPolyDataMapper> mapOutline =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapOutline->SetInputConnection(outlineData->GetOutputPort());

      vtkSmartPointer<vtkActor> outline =
        vtkSmartPointer<vtkActor>::New();
      outline->SetMapper(mapOutline);
      outline->GetProperty()->SetColor(colors->GetColor3d("Black").GetData());

      // It is convenient to create an initial view of the data. The FocalPoint
      // and Position form a vector direction. Later on (ResetCamera() method)
      // this vector is used to position the camera to look at the data in
      // this direction.
      vtkSmartPointer<vtkCamera> aCamera =
        vtkSmartPointer<vtkCamera>::New();
      aCamera->SetViewUp (0, 0, -1);
      aCamera->SetPosition (0, -1, 0);
      aCamera->SetFocalPoint (0, 0, 0);
      aCamera->ComputeViewPlaneNormal();
      aCamera->Azimuth(30.0);
      aCamera->Elevation(30.0);

      // Actors are added to the renderer. An initial camera view is created.
      // The Dolly() method moves the camera towards the FocalPoint,
      // thereby enlarging the image.
      aRenderer->AddActor(outline);
      aRenderer->AddActor(skin);
      aRenderer->SetActiveCamera(aCamera);
      aRenderer->ResetCamera ();
      aCamera->Dolly(1.5);

      // Set a background color for the renderer and set the size of the
      // render window (expressed in pixels).
      aRenderer->SetBackground(colors->GetColor3d("BkgColor").GetData());
      renWin->SetSize(640, 480);

      // Note that when camera movement occurs (as it does in the Dolly()
      // method), the clipping planes often need adjusting. Clipping planes
      // consist of two planes: near and far along the view direction. The
      // near plane clips out objects in front of the plane; the far plane
      // clips out objects behind the plane. This way only what is drawn
      // between the planes is actually rendered.
      aRenderer->ResetCameraClippingRange ();

      // Initialize the event loop and then start it.
      renWin->Render();
      iren->Initialize();
      iren->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(MedicalDemo1)

    find_package(VTK COMPONENTS
      vtkCommonColor
      vtkCommonCore
      vtkFiltersCore
      vtkFiltersModeling
      vtkIOImage
      vtkInteractionStyle
      vtkRenderingContextOpenGL2
      vtkRenderingCore
      vtkRenderingFreeType
      vtkRenderingGL2PSOpenGL2
      vtkRenderingOpenGL2 QUIET)
    if (NOT VTK_FOUND)
      message("Skipping MedicalDemo1: ${VTK_NOT_FOUND_MESSAGE}")
      return ()
    endif()
    message (STATUS "VTK_VERSION: ${VTK_VERSION}")
    if (VTK_VERSION VERSION_LESS "8.90.0")
      # old system
      include(${VTK_USE_FILE})
      add_executable(MedicalDemo1 MACOSX_BUNDLE MedicalDemo1.cxx )
      target_link_libraries(MedicalDemo1 PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(MedicalDemo1 MACOSX_BUNDLE MedicalDemo1.cxx )
      target_link_libraries(MedicalDemo1 PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS MedicalDemo1
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build MedicalDemo1

Click here to download MedicalDemo1 and its CMakeLists.txt file. Once the tarball MedicalDemo1.tar has been downloaded and extracted,

    cd MedicalDemo1/build

If VTK is installed:

    cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

    cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

    make

and run it:

    ./MedicalDemo1

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.