Skip to content

ImageLaplacian

vtk-examples/Cxx/Images/ImageLaplacian


Question

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

Code

ImageLaplacian.cxx

#include <vtkImageActor.h>
#include <vtkImageCast.h>
#include <vtkImageData.h>
#include <vtkImageLaplacian.h>
#include <vtkImageMandelbrotSource.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<vtkImageMandelbrotSource> source;
  source->Update();

  vtkNew<vtkImageCast> castOriginal;
  castOriginal->SetInputConnection(source->GetOutputPort());
  castOriginal->SetOutputScalarTypeToFloat();
  castOriginal->Update();

  vtkNew<vtkImageLaplacian> laplacianFilter;
  laplacianFilter->SetInputConnection(source->GetOutputPort());
  laplacianFilter->Update();

  vtkNew<vtkImageCast> castLaplacian;
  castLaplacian->SetInputConnection(laplacianFilter->GetOutputPort());
  castLaplacian->SetOutputScalarTypeToFloat();
  castLaplacian->Update();

  // 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};

  vtkNew<vtkImageActor> originalActor;
  originalActor->GetMapper()->SetInputConnection(castOriginal->GetOutputPort());

  vtkNew<vtkImageActor> laplacianActor;
  laplacianActor->GetMapper()->SetInputConnection(
      castLaplacian->GetOutputPort());

  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->SetSize(600, 300);
  renderWindow->SetWindowName("ImageLaplacian");

  vtkNew<vtkRenderWindowInteractor> interactor;

  vtkNew<vtkInteractorStyleImage> style;
  interactor->SetInteractorStyle(style);

  interactor->SetRenderWindow(renderWindow);

  // Setup both renderers
  vtkNew<vtkRenderer> originalRenderer;
  originalRenderer->SetViewport(leftViewport);
  originalRenderer->SetBackground(colors->GetColor3d("Sienna").GetData());

  vtkNew<vtkRenderer> laplacianRenderer;
  laplacianRenderer->SetViewport(rightViewport);
  laplacianRenderer->SetBackground(colors->GetColor3d("RoyalBlue").GetData());

  renderWindow->AddRenderer(originalRenderer);
  renderWindow->AddRenderer(laplacianRenderer);

  originalRenderer->AddActor(originalActor);
  laplacianRenderer->AddActor(laplacianActor);

  originalRenderer->ResetCamera();
  laplacianRenderer->ResetCamera();

  renderWindow->Render();
  interactor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(ImageLaplacian)

find_package(VTK COMPONENTS 
  vtkCommonColor
  vtkCommonCore
  vtkCommonDataModel
  vtkImagingCore
  vtkImagingGeneral
  vtkImagingSources
  vtkInteractionStyle
  vtkRenderingContextOpenGL2
  vtkRenderingCore
  vtkRenderingFreeType
  vtkRenderingGL2PSOpenGL2
  vtkRenderingOpenGL2
  QUIET
)

if (NOT VTK_FOUND)
  message("Skipping ImageLaplacian: ${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(ImageLaplacian MACOSX_BUNDLE ImageLaplacian.cxx )
  target_link_libraries(ImageLaplacian PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(ImageLaplacian MACOSX_BUNDLE ImageLaplacian.cxx )
  target_link_libraries(ImageLaplacian PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS ImageLaplacian
    MODULES ${VTK_LIBRARIES}
    )
endif ()

Download and Build ImageLaplacian

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

cd ImageLaplacian/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:

./ImageLaplacian

WINDOWS USERS

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