ITK/Examples/Functions/GaussianBlurImageFunction

This example shows how to apply the GaussianBlurImageFunction to an input image. The output is saved as a float or double image type.

GaussianBlurImageFunction.cxx

<source lang="cpp">

1. include "itkImage.h"
2. include "itkImageFileReader.h"
3. include "itkImageFileWriter.h"
4. include "itkGaussianBlurImageFunction.h"
5. include "itkImageRegionIterator.h"

int main( int argc, char * argv[] ) {

 if( argc < 5 ) {
   std::cerr << "Usage: " << std::endl;
   std::cerr << argv[0] << "  inputImageFile  outputImageFile sigma maxKernelWidth" << std::endl;
   return EXIT_FAILURE;
 }

 typedef itk::Image< float, 2 >             ImageType;
 typedef itk::ImageFileReader< ImageType >  ReaderType;
 typedef itk::ImageRegionIterator< ImageType > IteratorType;
 typedef itk::ImageRegionConstIterator< ImageType > ConstIteratorType;

 ReaderType::Pointer reader = ReaderType::New();
 reader->SetFileName( argv[1] );
 reader->Update();

 const ImageType * inputImage = reader->GetOutput();

 ImageType::RegionType region = inputImage->GetBufferedRegion();

 ConstIteratorType it( inputImage, region );

 ImageType::Pointer output = ImageType::New();

 output->SetRegions( region );
 output->SetOrigin(  inputImage->GetOrigin()  );
 output->SetSpacing( inputImage->GetSpacing() );
 output->Allocate();

 IteratorType out( output, region );

 typedef itk::GaussianBlurImageFunction< ImageType > GFunctionType;
 GFunctionType::Pointer gaussianFunction = GFunctionType::New();
 gaussianFunction->SetInputImage( inputImage );

 GFunctionType::ErrorArrayType setError;
 setError.Fill( 0.01 );
 gaussianFunction->SetMaximumError( setError );
 gaussianFunction->SetSigma( atof( argv[3] ) );
 gaussianFunction->SetMaximumKernelWidth( atoi( argv[4] ) );

 it.GoToBegin();
 out.GoToBegin();

 while( !it.IsAtEnd() )
   {
   out.Set( gaussianFunction->EvaluateAtIndex(it.GetIndex() ) );
   ++it;
   ++out;
   }

 typedef itk::ImageFileWriter < ImageType > WriterType;
 WriterType::Pointer writer = WriterType::New();
 writer->SetFileName(argv[2]);
 writer->SetInput(output);
 writer->Update();

 return EXIT_SUCCESS;

} </source>

CMakeLists.txt

<syntaxhighlight lang="cmake"> cmake_minimum_required(VERSION 3.9.5)

project(GaussianBlurImageFunction)

find_package(ITK REQUIRED) include(${ITK_USE_FILE}) if (ITKVtkGlue_LOADED)

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

else()

 find_package(ItkVtkGlue REQUIRED)
 include(${ItkVtkGlue_USE_FILE})
 set(Glue ItkVtkGlue)

endif()

add_executable(GaussianBlurImageFunction MACOSX_BUNDLE GaussianBlurImageFunction.cxx) target_link_libraries(GaussianBlurImageFunction

 ${Glue}  ${VTK_LIBRARIES} ${ITK_LIBRARIES})

</syntaxhighlight>

Download and Build GaussianBlurImageFunction

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

cd GaussianBlurImageFunction/build 

• If ITK is installed:

cmake ..

• If ITK is not installed but compiled on your system, you will need to specify the path to your ITK build:

cmake -DITK_DIR:PATH=/home/me/itk_build ..

Build the project,

make

and run it:

./GaussianBlurImageFunction

WINDOWS USERS PLEASE NOTE: Be sure to add the VTK and ITK bin directories to your path. This will resolve the VTK and ITK dll's at run time.

Building All of the Examples

Many of the examples in the ITK Wiki Examples Collection require VTK. You can build all of the the examples by following these instructions. If you are a new VTK user, you may want to try the Superbuild which will build a proper ITK and VTK.

ItkVtkGlue

ITK >= 4

For examples that use QuickView (which depends on VTK), you must have built ITK with Module_ITKVtkGlue=ON.

ITK < 4

Some of the ITK Examples require VTK to display the images. If you download the entire ITK Wiki Examples Collection, the ItkVtkGlue directory will be included and configured. If you wish to just build a few examples, then you will need to download ItkVtkGlue and build it. When you run cmake it will ask you to specify the location of the ItkVtkGlue binary directory.