# ImageSeparableConvolution

VTKExamples/Cxx/Images/ImageSeparableConvolution

### Description

Read in a binary image and convolve it with a separable kernel. The input and output are displayed.

### Code

ImageSeparableConvolution.cxx

    #include <vtkImageActor.h>
    #include <vtkFloatArray.h>
    #include <vtkImageCast.h>
    #include <vtkImageMapper3D.h>
    #include <vtkInteractorStyleImage.h>
    #include <vtkImageAccumulate.h>
    #include <vtkImageData.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkSmartPointer.h>
    #include <vtkPNGReader.h>
    #include <vtkImageSeparableConvolution.h>
    #include <vtkImageThreshold.h>

    int main(int argc, char *argv[])
    {
      // Handle the arguments
      if( argc < 2 )
      {
        std::cout << "Required arguments: BinaryImage.png" << std::endl;
        return EXIT_FAILURE;
      }

      // Read the image
      vtkSmartPointer<vtkPNGReader> reader =
        vtkSmartPointer<vtkPNGReader>::New();
      reader->SetFileName(argv[1]);
      reader->Update();

      vtkSmartPointer<vtkFloatArray> xKernel =
        vtkSmartPointer<vtkFloatArray>::New();
      xKernel->SetNumberOfTuples(5);
      xKernel->SetNumberOfComponents(1);
      xKernel->SetValue(0,1);
      xKernel->SetValue(1,1);
      xKernel->SetValue(2,1);
      xKernel->SetValue(3,1);
      xKernel->SetValue(4,1);

      vtkSmartPointer<vtkImageSeparableConvolution> convolutionFilter =
        vtkSmartPointer<vtkImageSeparableConvolution>::New();
      convolutionFilter->SetInputConnection(reader->GetOutputPort());
      convolutionFilter->SetXKernel(xKernel);
      convolutionFilter->Update();

      vtkSmartPointer<vtkImageActor> originalActor =
        vtkSmartPointer<vtkImageActor>::New();
      originalActor->GetMapper()->SetInputConnection(
        reader->GetOutputPort());

      vtkSmartPointer<vtkImageCast> convolutionCastFilter =
        vtkSmartPointer<vtkImageCast>::New();
      convolutionCastFilter->SetInputConnection(convolutionFilter->GetOutputPort());
      convolutionCastFilter->SetOutputScalarTypeToUnsignedChar();
      convolutionCastFilter->Update();

      vtkSmartPointer<vtkImageActor> convolutionActor =
        vtkSmartPointer<vtkImageActor>::New();
      convolutionActor->GetMapper()->SetInputConnection(
        convolutionCastFilter->GetOutputPort());

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

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

      vtkSmartPointer<vtkRenderer> convolutionRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      convolutionRenderer->SetViewport(convolutionViewport);
      convolutionRenderer->AddActor(convolutionActor);
      convolutionRenderer->ResetCamera();
      convolutionRenderer->SetBackground(.4, .5, .7);

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

      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(ImageSeparableConvolution)

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

    add_executable(ImageSeparableConvolution MACOSX_BUNDLE ImageSeparableConvolution.cxx )

    target_link_libraries(ImageSeparableConvolution ${VTK_LIBRARIES})

### Download and Build ImageSeparableConvolution

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

    cd ImageSeparableConvolution/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:

    ./ImageSeparableConvolution

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.