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MedicalDemo2

Repository source: MedicalDemo2


Description

Skin and bone isosurfaces.

Usage

MedicalDemo2 FullHead.mhd

Note

The skin color was selected from Table 7 in Improvement of Haar Feature Based Face Detection in OpenCV Incorporating Human Skin Color Characteristic

Note

The original source code for this example is here.

Info

The example uses src/Testing/Data/FullHead.mhd which references src/Testing/Data/FullHead.raw.gz.

Other languages

See (Python), (PythonicAPI), (Java)

Question

If you have a question about this example, please use the VTK Discourse Forum

Code

MedicalDemo2.cxx

// Derived from VTK/Examples/Cxx/Medical2.cxx
// This example reads a volume dataset, extracts two isosurfaces that
// represent the skin and bone, and then displays them.
//

#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkFlyingEdges3D.h>
#include <vtkInteractorStyleSwitch.h>
#include <vtkMarchingCubes.h>
#include <vtkMetaImageReader.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkOutlineFilter.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkStripper.h>

#include <vtk_cli11.h>

#include <array>
#include <filesystem>

namespace fs = std::filesystem;

int main(int argc, char* argv[])
{
  CLI::App app{
      "The Skin and bone isosurfaces extracted from a CT dataset of the head."};

  // Define options
  std::string fileName;
  app.add_option("fileName", fileName,
                 "The path to the data file e.g. FullHead.mhd.")
      ->required()
      ->check(CLI::ExistingFile);

  bool flyingEdges = true;
  app.add_flag("-m{false},!-n", flyingEdges,
               "Use flying edges by default, marching cubes if set.");

  CLI11_PARSE(app, argc, argv);

  if (flyingEdges)
  {
#define USE_FLYING_EDGES
  }

  vtkNew<vtkNamedColors> colors;

  // Set the colors.
  std::array<unsigned char, 4> skinColor{{240, 184, 160, 255}};
  colors->SetColor("SkinColor", skinColor.data());
  std::array<unsigned char, 4> backColor{{255, 229, 200, 255}};
  colors->SetColor("BackfaceColor", backColor.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.
  //
  vtkNew<vtkRenderer> ren;
  vtkNew<vtkRenderWindow> renWin;
  // Set a background color for the renderer and set the size of the
  // render window (expressed in pixels).
  ren->SetBackground(colors->GetColor3d("BkgColor").GetData());
  renWin->SetSize(640, 480);
  auto appFn = fs::path((app.get_name())).stem().string();
  renWin->SetWindowName(appFn.c_str());
  renWin->AddRenderer(ren);

  vtkNew<vtkRenderWindowInteractor> iren;
  iren->SetRenderWindow(renWin);
  auto is = vtkInteractorStyleSwitch::SafeDownCast(iren->GetInteractorStyle());
  if (is)
  {
    is->SetCurrentStyleToTrackballCamera();
  }

  // The following reader is used to read a series of 2D slices (images)
  // that compose the volume. The slice dimensions are set, and the
  // pixel spacing. The data Endianness must also be specified. The reader
  // uses the FilePrefix in combination with the slice number to construct
  // filenames using the format FilePrefix.%d. (In this case the FilePrefix
  // is the root name of the file: quarter.)
  vtkNew<vtkMetaImageReader> reader;
  reader->SetFileName(argv[1]);

  // An isosurface, or contour value of 500 is known to correspond to the
  // skin of the patient.
  // The triangle stripper is used to create triangle strips from the
  // isosurface; these render much faster on many systems.
#ifdef USE_FLYING_EDGES
  vtkNew<vtkFlyingEdges3D> skinExtractor;
#else
  vtkNew<vtkMarchingCubes> skinExtractor;
#endif
  skinExtractor->SetInputConnection(reader->GetOutputPort());
  skinExtractor->SetValue(0, 500);

  // The triangle stripper is used to create triangle strips from the
  // isosurface these render much faster on many systems.
  vtkNew<vtkStripper> skinStripper;
  skinStripper->SetInputConnection(skinExtractor->GetOutputPort());

  vtkNew<vtkPolyDataMapper> skinMapper;
  skinMapper->SetInputConnection(skinStripper->GetOutputPort());
  skinMapper->ScalarVisibilityOff();

  vtkNew<vtkProperty> backProp;
  backProp->SetDiffuseColor(colors->GetColor3d("BackfaceColor").GetData());

  vtkNew<vtkActor> skin;
  skin->SetMapper(skinMapper);
  skin->GetProperty()->SetDiffuseColor(
      colors->GetColor3d("SkinColor").GetData());
  skin->GetProperty()->SetSpecular(0.3);
  skin->GetProperty()->SetSpecularPower(20);
  skin->GetProperty()->SetOpacity(0.5);
  skin->SetBackfaceProperty(backProp);

  // An isosurface, or contour value of 1150 is known to correspond to the
  // bone of the patient.
  // The triangle stripper is used to create triangle strips from the
  // isosurface; these render much faster on may systems.
  vtkNew<vtkFlyingEdges3D> boneExtractor;
  boneExtractor->SetInputConnection(reader->GetOutputPort());
  boneExtractor->SetValue(0, 1150);

  vtkNew<vtkStripper> boneStripper;
  boneStripper->SetInputConnection(boneExtractor->GetOutputPort());

  vtkNew<vtkPolyDataMapper> boneMapper;
  boneMapper->SetInputConnection(boneStripper->GetOutputPort());
  boneMapper->ScalarVisibilityOff();

  vtkNew<vtkActor> bone;
  bone->SetMapper(boneMapper);
  bone->GetProperty()->SetDiffuseColor(colors->GetColor3d("Ivory").GetData());

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

  vtkNew<vtkPolyDataMapper> outlineMapper;
  outlineMapper->SetInputConnection(outlineData->GetOutputPort());

  vtkNew<vtkActor> outline;
  outline->SetMapper(outlineMapper);
  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.
  vtkNew<vtkCamera> camera;
  camera->SetViewUp(0, 0, 1);
  camera->SetPosition(0, -1, 0);
  camera->SetFocalPoint(0, 0, 0);
  camera->ComputeViewPlaneNormal();
  camera->Azimuth(30.0);
  camera->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.
  ren->AddActor(outline);
  ren->AddActor(skin);
  ren->AddActor(bone);
  ren->SetActiveCamera(camera);
  ren->ResetCamera();
  camera->Dolly(1.5);

  // 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.
  ren->ResetCameraClippingRange();

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

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(MedicalDemo2)

find_package(VTK COMPONENTS 
  CommonColor
  CommonCore
  FiltersCore
  FiltersModeling
  IOImage
  InteractionStyle
  RenderingContextOpenGL2
  RenderingCore
  RenderingFreeType
  RenderingGL2PSOpenGL2
  RenderingOpenGL2
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "MedicalDemo2: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
add_executable(MedicalDemo2 MACOSX_BUNDLE MedicalDemo2.cxx )
  target_link_libraries(MedicalDemo2 PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS MedicalDemo2
  MODULES ${VTK_LIBRARIES}
)

Download and Build MedicalDemo2

Click here to download MedicalDemo2 and its CMakeLists.txt file. Once the tarball MedicalDemo2.tar has been downloaded and extracted,

cd MedicalDemo2/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:

./MedicalDemo2

WINDOWS USERS

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