ImageIslandRemoval2D

Description¶

This example creates a small white square and a big white square. We want the ImageIslandRemoval2D to turn the small white square black and leave the big white square alone.

Question

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

Code¶

ImageIslandRemoval2D.cxx

#include <vtkImageActor.h>
#include <vtkImageCanvasSource2D.h>
#include <vtkImageCast.h>
#include <vtkImageData.h>
#include <vtkImageEllipsoidSource.h>
#include <vtkImageIslandRemoval2D.h>
#include <vtkImageMapper3D.h>
#include <vtkInteractorStyleImage.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>

int main(int, char*[])
{
  vtkNew<vtkNamedColors> colors;

  // Create an image
  vtkNew<vtkImageCanvasSource2D> imageSource;
  imageSource->SetScalarTypeToUnsignedChar();
  imageSource->SetNumberOfScalarComponents(1);
  imageSource->SetExtent(0, 200, 0, 200, 0, 0);

  // Blank the image
  imageSource->SetDrawColor(0.0);
  imageSource->FillBox(0, 200, 0, 200);

  // Draw a small box
  imageSource->SetDrawColor(255.0);
  imageSource->FillBox(100, 105, 100, 105);

  // Draw a large box
  imageSource->SetDrawColor(255.0);
  imageSource->FillBox(150, 170, 150, 170);

  imageSource->Update();

  vtkNew<vtkImageIslandRemoval2D> islandRemovalFilter;
  islandRemovalFilter->SetAreaThreshold(50);
  islandRemovalFilter->SetIslandValue(255.0);
  islandRemovalFilter->SetReplaceValue(0.0);
  islandRemovalFilter->SetInputConnection(imageSource->GetOutputPort());
  islandRemovalFilter->Update();

  // Visualize
  vtkNew<vtkImageActor> originalActor;
  originalActor->GetMapper()->SetInputConnection(imageSource->GetOutputPort());

  vtkNew<vtkImageActor> islandRemovalActor;
  islandRemovalActor->GetMapper()->SetInputConnection(
      islandRemovalFilter->GetOutputPort());

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

  // Setup renderers
  vtkNew<vtkRenderer> originalRenderer;
  originalRenderer->SetViewport(originalViewport);
  originalRenderer->AddActor(originalActor);
  originalRenderer->ResetCamera();
  originalRenderer->SetBackground(
      colors->GetColor3d("CornflowerBlue").GetData());

  vtkNew<vtkRenderer> islandRemovalRenderer;
  islandRemovalRenderer->SetViewport(islandRemovalViewport);
  islandRemovalRenderer->AddActor(islandRemovalActor);
  islandRemovalRenderer->ResetCamera();
  islandRemovalRenderer->SetBackground(
      colors->GetColor3d("SteelBlue").GetData());

  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->SetSize(600, 300);
  renderWindow->AddRenderer(originalRenderer);
  renderWindow->AddRenderer(islandRemovalRenderer);
  renderWindow->SetWindowName("ImageIslandRemoval2D");

  vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
  vtkNew<vtkInteractorStyleImage> style;

  renderWindowInteractor->SetInteractorStyle(style);

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

  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt¶

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(ImageIslandRemoval2D)

find_package(VTK COMPONENTS 
  CommonColor
  CommonCore
  CommonDataModel
  ImagingCore
  ImagingMorphological
  ImagingSources
  InteractionStyle
  RenderingContextOpenGL2
  RenderingCore
  RenderingFreeType
  RenderingGL2PSOpenGL2
  RenderingOpenGL2
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "ImageIslandRemoval2D: 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(ImageIslandRemoval2D MACOSX_BUNDLE ImageIslandRemoval2D.cxx )
  target_link_libraries(ImageIslandRemoval2D PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS ImageIslandRemoval2D
  MODULES ${VTK_LIBRARIES}
)

Download and Build ImageIslandRemoval2D¶

Click here to download ImageIslandRemoval2D and its CMakeLists.txt file. Once the tarball ImageIslandRemoval2D.tar has been downloaded and extracted,

cd ImageIslandRemoval2D/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:

./ImageIslandRemoval2D

WINDOWS USERS

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