HybridMedianComparison
vtk-examples/Cxx/ImageProcessing/HybridMedianComparison
Description¶
Comparison of median and hybrid-median filters. The hybrid filter preserves corners and thin lines, better than the median filter. The lower patterns represent the three neighborhoods used to compute the hybrid median.
Info
See this figure in Chapter 10 the VTK Textbook.
Other languages
See (Python)
Question
If you have a question about this example, please use the VTK Discourse Forum
Code¶
HybridMedianComparison.cxx
#include <vtkCamera.h>
#include <vtkDataArray.h>
#include <vtkImageActor.h>
#include <vtkImageCast.h>
#include <vtkImageData.h>
#include <vtkImageHybridMedian2D.h>
#include <vtkImageMapper3D.h>
#include <vtkImageMathematics.h>
#include <vtkImageMedian3D.h>
#include <vtkImageNoiseSource.h>
#include <vtkImageProperty.h>
#include <vtkImageReader2.h>
#include <vtkImageReader2Factory.h>
#include <vtkImageThreshold.h>
#include <vtkInteractorStyleImage.h>
#include <vtkNew.h>
#include <vtkPointData.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSmartPointer.h>
#include <vector>
namespace {
void AddShotNoise(vtkImageData* inputImage, vtkImageData* outputImage,
double noiseAmplitude, double noiseFraction, int extent[6]);
}
int main(int argc, char* argv[])
{
// Verify input arguments
if (argc != 2)
{
std::cout << "Usage: " << argv[0] << " Filename e.g. TestPattern.png"
<< std::endl;
return EXIT_FAILURE;
}
// Read the image
vtkNew<vtkImageReader2Factory> readerFactory;
vtkSmartPointer<vtkImageReader2> reader;
reader.TakeReference(readerFactory->CreateImageReader2(argv[1]));
reader->SetFileName(argv[1]);
reader->Update();
int scalarRange[2];
scalarRange[0] =
reader->GetOutput()->GetPointData()->GetScalars()->GetRange()[0];
scalarRange[1] =
reader->GetOutput()->GetPointData()->GetScalars()->GetRange()[1];
std::cout << "Range: " << scalarRange[0] << ", " << scalarRange[1]
<< std::endl;
int middleSlice = (reader->GetOutput()->GetExtent()[5] -
reader->GetOutput()->GetExtent()[4]) /
2;
// Work with double images
vtkNew<vtkImageCast> cast;
cast->SetInputConnection(reader->GetOutputPort());
cast->SetOutputScalarTypeToDouble();
cast->Update();
vtkNew<vtkImageData> originalData;
originalData->DeepCopy(cast->GetOutput());
vtkNew<vtkImageData> noisyData;
AddShotNoise(originalData, noisyData, 2000.0, .1,
reader->GetOutput()->GetExtent());
vtkNew<vtkImageMedian3D> median;
median->SetInputData(noisyData);
median->SetKernelSize(5, 5, 1);
vtkNew<vtkImageHybridMedian2D> hybridMedian1;
hybridMedian1->SetInputData(noisyData);
vtkNew<vtkImageHybridMedian2D> hybridMedian;
hybridMedian->SetInputConnection(hybridMedian1->GetOutputPort());
int colorWindow = (scalarRange[1] - scalarRange[0]);
int colorLevel = colorWindow / 2;
vtkNew<vtkImageActor> originalActor;
originalActor->GetMapper()->SetInputData(originalData);
originalActor->GetProperty()->SetColorWindow(colorWindow);
originalActor->GetProperty()->SetColorLevel(colorLevel);
originalActor->GetProperty()->SetInterpolationTypeToNearest();
originalActor->SetDisplayExtent(
reader->GetDataExtent()[0], reader->GetDataExtent()[1],
reader->GetDataExtent()[2], reader->GetDataExtent()[3], middleSlice,
middleSlice);
vtkNew<vtkImageActor> noisyActor;
noisyActor->GetMapper()->SetInputData(noisyData);
noisyActor->GetProperty()->SetColorWindow(colorWindow);
noisyActor->GetProperty()->SetColorLevel(colorLevel);
noisyActor->GetProperty()->SetInterpolationTypeToNearest();
noisyActor->SetDisplayExtent(originalActor->GetDisplayExtent());
vtkNew<vtkImageActor> hybridMedianActor;
hybridMedianActor->GetMapper()->SetInputConnection(
hybridMedian->GetOutputPort());
hybridMedianActor->GetProperty()->SetColorWindow(colorWindow);
hybridMedianActor->GetProperty()->SetColorLevel(colorLevel);
hybridMedianActor->GetProperty()->SetInterpolationTypeToNearest();
hybridMedianActor->SetDisplayExtent(originalActor->GetDisplayExtent());
vtkNew<vtkImageActor> medianActor;
medianActor->GetMapper()->SetInputConnection(median->GetOutputPort());
medianActor->GetProperty()->SetColorWindow(colorWindow);
medianActor->GetProperty()->SetColorLevel(colorLevel);
medianActor->GetProperty()->SetInterpolationTypeToNearest();
medianActor->SetDisplayExtent(originalActor->GetDisplayExtent());
// Setup renderers
vtkNew<vtkRenderer> originalRenderer;
originalRenderer->AddActor(originalActor);
vtkNew<vtkRenderer> noisyRenderer;
noisyRenderer->AddActor(noisyActor);
vtkNew<vtkRenderer> hybridRenderer;
hybridRenderer->AddActor(hybridMedianActor);
vtkNew<vtkRenderer> medianRenderer;
medianRenderer->AddActor(medianActor);
std::vector<vtkSmartPointer<vtkRenderer>> renderers;
renderers.push_back(originalRenderer);
renderers.push_back(noisyRenderer);
renderers.push_back(hybridRenderer);
renderers.push_back(medianRenderer);
// Setup viewports for the renderers
int rendererSize = 400;
unsigned int xGridDimensions = 2;
unsigned int yGridDimensions = 2;
vtkNew<vtkRenderWindow> renderWindow;
renderWindow->SetSize(rendererSize * xGridDimensions,
rendererSize * yGridDimensions);
for (int row = 0; row < static_cast<int>(yGridDimensions); row++)
{
for (int col = 0; col < static_cast<int>(xGridDimensions); col++)
{
int index = row * xGridDimensions + col;
// (xmin, ymin, xmax, ymax)
double viewport[4] = {
static_cast<double>(col) / xGridDimensions,
static_cast<double>(yGridDimensions - (row + 1)) / yGridDimensions,
static_cast<double>(col + 1) / xGridDimensions,
static_cast<double>(yGridDimensions - row) / yGridDimensions};
renderers[index]->SetViewport(viewport);
renderWindow->AddRenderer(renderers[index]);
}
}
renderWindow->SetWindowName("HybridMedianComparison");
vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
vtkNew<vtkInteractorStyleImage> style;
renderWindowInteractor->SetInteractorStyle(style);
renderWindowInteractor->SetRenderWindow(renderWindow);
// Renderers share one camera
renderWindow->Render();
renderers[0]->GetActiveCamera()->Dolly(1.5);
renderers[0]->ResetCameraClippingRange();
for (size_t r = 1; r < renderers.size(); ++r)
{
renderers[r]->SetActiveCamera(renderers[0]->GetActiveCamera());
}
renderWindowInteractor->Initialize();
renderWindowInteractor->Start();
return EXIT_SUCCESS;
}
namespace {
void AddShotNoise(vtkImageData* inputImage, vtkImageData* outputImage,
double noiseAmplitude, double noiseFraction, int extent[6])
{
vtkNew<vtkImageNoiseSource> shotNoiseSource;
shotNoiseSource->SetWholeExtent(extent);
shotNoiseSource->SetMinimum(0.0);
shotNoiseSource->SetMaximum(1.0);
vtkNew<vtkImageThreshold> shotNoiseThresh1;
shotNoiseThresh1->SetInputConnection(shotNoiseSource->GetOutputPort());
shotNoiseThresh1->ThresholdByLower(1.0 - noiseFraction);
shotNoiseThresh1->SetInValue(0);
shotNoiseThresh1->SetOutValue(noiseAmplitude);
vtkNew<vtkImageThreshold> shotNoiseThresh2;
shotNoiseThresh2->SetInputConnection(shotNoiseSource->GetOutputPort());
shotNoiseThresh2->ThresholdByLower(noiseFraction);
shotNoiseThresh2->SetInValue(1.0 - noiseAmplitude);
shotNoiseThresh2->SetOutValue(0.0);
vtkNew<vtkImageMathematics> shotNoise;
shotNoise->SetInputConnection(0, shotNoiseThresh1->GetOutputPort());
shotNoise->SetInputConnection(1, shotNoiseThresh2->GetOutputPort());
shotNoise->SetOperationToAdd();
vtkNew<vtkImageMathematics> add;
add->SetInputData(0, inputImage);
add->SetInputConnection(1, shotNoise->GetOutputPort());
add->SetOperationToAdd();
add->Update();
outputImage->DeepCopy(add->GetOutput());
}
} // namespace
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
project(HybridMedianComparison)
find_package(VTK COMPONENTS
vtkCommonCore
vtkCommonDataModel
vtkIOImage
vtkImagingCore
vtkImagingGeneral
vtkImagingMath
vtkImagingSources
vtkInteractionStyle
vtkRenderingContextOpenGL2
vtkRenderingCore
vtkRenderingFreeType
vtkRenderingGL2PSOpenGL2
vtkRenderingOpenGL2
QUIET
)
if (NOT VTK_FOUND)
message("Skipping HybridMedianComparison: ${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(HybridMedianComparison MACOSX_BUNDLE HybridMedianComparison.cxx )
target_link_libraries(HybridMedianComparison PRIVATE ${VTK_LIBRARIES})
else ()
# include all components
add_executable(HybridMedianComparison MACOSX_BUNDLE HybridMedianComparison.cxx )
target_link_libraries(HybridMedianComparison PRIVATE ${VTK_LIBRARIES})
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS HybridMedianComparison
MODULES ${VTK_LIBRARIES}
)
endif ()
Download and Build HybridMedianComparison¶
Click here to download HybridMedianComparison and its CMakeLists.txt file. Once the tarball HybridMedianComparison.tar has been downloaded and extracted,
cd HybridMedianComparison/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:
./HybridMedianComparison
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.