# ImageMedian3D

VTKExamples/Cxx/Images/ImageMedian3D

### Code

ImageMedian3D.cxx

    #include <vtkSmartPointer.h>
    #include <vtkImageData.h>
    #include <vtkImageCanvasSource2D.h>
    #include <vtkImageMedian3D.h>
    #include <vtkImageMapper3D.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkInteractorStyleImage.h>
    #include <vtkRenderer.h>
    #include <vtkJPEGReader.h>
    #include <vtkImageActor.h>
    #include <vtkImageCast.h>

    int main(int, char *[])
    {
      // Create an image
      vtkSmartPointer<vtkImageCanvasSource2D> imageSource =
        vtkSmartPointer<vtkImageCanvasSource2D>::New();
      imageSource->SetNumberOfScalarComponents(1);
      imageSource->SetScalarTypeToUnsignedChar();
      unsigned int xmin = 0;
      unsigned int xmax = 20;
      unsigned int ymin = 0;
      unsigned int ymax = 20;
      imageSource->SetExtent(xmin, xmax, ymin, ymax, 0, 0);

      // Make the image all black
      imageSource->SetDrawColor(0.0);
      imageSource->FillBox(xmin, xmax, ymin, ymax);

      // Draw a big white square
      imageSource->SetDrawColor(255.0);
      imageSource->FillBox(5, 15, 5, 15);

      // Add some single white pixels
      imageSource->SetDrawColor(255.0);
      imageSource->FillBox(1, 1, 1, 1);
      imageSource->FillBox(17, 17, 17, 17);

      imageSource->Update();

      vtkSmartPointer<vtkImageMedian3D> medianFilter =
        vtkSmartPointer<vtkImageMedian3D>::New();
      medianFilter->SetInputConnection(imageSource->GetOutputPort());
      medianFilter->SetKernelSize(3,3,1);
      medianFilter->Update();

      // Create actors
      vtkSmartPointer<vtkImageActor> originalActor =
        vtkSmartPointer<vtkImageActor>::New();
      originalActor->GetMapper()->SetInputConnection(
        imageSource->GetOutputPort());

      vtkSmartPointer<vtkImageActor> medianActor =
        vtkSmartPointer<vtkImageActor>::New();
      medianActor->GetMapper()->SetInputConnection(
        medianFilter->GetOutputPort());

      // Define viewport ranges
      // (xmin, ymin, xmax, ymax)
      double leftViewport[4] = {0.0, 0.0, 0.5, 1.0};
      double rightViewport[4] = {0.5, 0.0, 1.0, 1.0};

      // Setup renderers
      vtkSmartPointer<vtkRenderer> originalRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      originalRenderer->SetViewport(leftViewport);
      originalRenderer->AddActor(originalActor);
      originalRenderer->ResetCamera();
      originalRenderer->SetBackground(.4, .5, .6);

      vtkSmartPointer<vtkRenderer> gradientMagnitudeRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      gradientMagnitudeRenderer->SetViewport(rightViewport);
      gradientMagnitudeRenderer->AddActor(medianActor);
      gradientMagnitudeRenderer->ResetCamera();
      gradientMagnitudeRenderer->SetBackground(.4, .5, .7);

      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->SetSize(600, 300);
      renderWindow->AddRenderer(originalRenderer);
      renderWindow->AddRenderer(gradientMagnitudeRenderer);

      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      vtkSmartPointer<vtkInteractorStyleImage> style =
        vtkSmartPointer<vtkInteractorStyleImage>::New();

      renderWindowInteractor->SetInteractorStyle(style);

      renderWindowInteractor->SetRenderWindow(renderWindow);
      renderWindowInteractor->Initialize();

      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(ImageMedian3D)

    find_package(VTK REQUIRED)
    include(${VTK_USE_FILE})

    add_executable(ImageMedian3D MACOSX_BUNDLE ImageMedian3D.cxx)

    target_link_libraries(ImageMedian3D ${VTK_LIBRARIES})

### Download and Build ImageMedian3D

Danger

The generation of tar files has not been ported to the new VTKExamples. Some tarballs may be missing or out-of-date.

Click here to download ImageMedian3D and its CMakeLists.txt file. Once the tarball ImageMedian3D.tar has been downloaded and extracted,

    cd ImageMedian3D/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:

    ./ImageMedian3D

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