GaussianSmooth
VTKExamples/Cxx/ImageProcessing/GaussianSmooth
Description¶
Low-pass filters can be implemented as convolution with a Gaussian kernel. The Gaussian kernel displayed on top has been magnified for this figure.
Info
See this figure in Chapter 10 the VTK Textbook.
Other Languages
See (Python)
Code¶
GaussianSmooth.cxx
#include <vtkImageActor.h> #include <vtkImageCast.h> #include <vtkImageData.h> #include <vtkImageGaussianSmooth.h> #include <vtkImageMapper3D.h> #include <vtkImageNoiseSource.h> #include <vtkImageReader2.h> #include <vtkImageReader2Factory.h> #include <vtkInteractorStyleImage.h> #include <vtkInteractorStyleImage.h> #include <vtkNamedColors.h> #include <vtkRenderer.h> #include <vtkRenderWindow.h> #include <vtkRenderWindowInteractor.h> #include <vtkSmartPointer.h> int main( int argc, char *argv[]) { // Verify input arguments if ( argc != 2 ) { std::cout << "Usage: " << argv[0] << " Filename" << std::endl; return EXIT_FAILURE; } // Read the image vtkSmartPointer<vtkImageReader2Factory> readerFactory = vtkSmartPointer<vtkImageReader2Factory>::New(); vtkSmartPointer<vtkImageReader2> reader = readerFactory->CreateImageReader2(argv[1]); reader->SetFileName(argv[1]); reader->Update(); // Process the image vtkSmartPointer<vtkImageCast> cast = vtkSmartPointer<vtkImageCast>::New(); cast->SetInputConnection(reader->GetOutputPort()); cast->SetOutputScalarTypeToFloat(); vtkSmartPointer<vtkImageGaussianSmooth> filter = vtkSmartPointer<vtkImageGaussianSmooth>::New(); filter->SetDimensionality(2); filter->SetInputConnection(cast->GetOutputPort()); filter->SetStandardDeviations(4.0, 4.0); filter->SetRadiusFactors(2.0, 2.0); // Create actors vtkSmartPointer<vtkNamedColors> colors = vtkSmartPointer<vtkNamedColors>::New(); vtkSmartPointer<vtkImageActor> originalActor = vtkSmartPointer<vtkImageActor>::New(); originalActor->GetMapper()->SetInputConnection( reader->GetOutputPort()); vtkSmartPointer<vtkImageActor> filteredActor = vtkSmartPointer<vtkImageActor>::New(); filteredActor->GetMapper()->SetInputConnection( filter->GetOutputPort()); // Define viewport ranges // (xmin, ymin, xmax, ymax) double originalViewport[4] = {0.0, 0.0, 0.5, 1.0}; double filteredViewport[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(colors->GetColor3d("SlateGray").GetData()); vtkSmartPointer<vtkRenderer> filteredRenderer = vtkSmartPointer<vtkRenderer>::New(); filteredRenderer->SetViewport(filteredViewport); filteredRenderer->AddActor(filteredActor); filteredRenderer->ResetCamera(); filteredRenderer->SetBackground(colors->GetColor3d("LightSlateGray").GetData()); vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New(); renderWindow->SetSize(600, 300); renderWindow->AddRenderer(originalRenderer); renderWindow->AddRenderer(filteredRenderer); 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(GaussianSmooth) find_package(VTK REQUIRED) include(${VTK_USE_FILE}) add_executable(GaussianSmooth MACOSX_BUNDLE GaussianSmooth.cxx ) target_link_libraries(GaussianSmooth ${VTK_LIBRARIES})
Download and Build GaussianSmooth¶
Click here to download GaussianSmooth and its CMakeLists.txt file. Once the tarball GaussianSmooth.tar has been downloaded and extracted,
cd GaussianSmooth/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:
./GaussianSmooth
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.