ITK/Examples/Smoothing/SmoothingRecursiveGaussianImageFilter

This examples uses image adaptors to smooth RGB images. Each component is smoothed separately and the 3 resulting images are composed into an RGBImage.

SmoothingRecursiveGaussianImageFilter.cxx

<source lang="cpp">

1. include "itkImage.h"
2. include "itkImageFileReader.h"
3. include "itkDiscreteGaussianImageFilter.h"
4. include "itkSmoothingRecursiveGaussianImageFilter.h"
5. include "itkRGBPixel.h"
6. include "itkNthElementImageAdaptor.h"
7. include "itkComposeRGBImageFilter.h"

1. include "QuickView.h"

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

 // Verify command line arguments
 if( argc < 2 )
   {
   std::cerr << "Usage: " << std::endl;
   std::cerr << argv[0] << " inputImageFile [sigma]" << std::endl;
   return EXIT_FAILURE;
   }

 double sigma = 4.0;
 if (argc > 2)
   {
   sigma = atof(argv[2]);
   }

 const unsigned int Dimension = 2;
 typedef unsigned char PixelComponentType;

 typedef itk::Image<itk::RGBPixel< PixelComponentType>,
   Dimension > ColorImageType;
 typedef itk::Image<PixelComponentType, Dimension >
   ScalarImageType;
 typedef itk::ImageFileReader< ColorImageType >
   ReaderType;
 // Create and setup a reader
 ReaderType::Pointer reader = ReaderType::New();
 reader->SetFileName( argv[1] );
 reader->Update();

 typedef itk::NthElementImageAdaptor<ColorImageType,
   PixelComponentType> ImageAdaptorType;

 typedef itk::SmoothingRecursiveGaussianImageFilter<
   ImageAdaptorType, ScalarImageType >  FilterType;

 ImageAdaptorType::Pointer adaptorR = ImageAdaptorType::New();
 adaptorR->SelectNthElement(0);
 adaptorR->SetImage(reader->GetOutput());

 FilterType::Pointer gaussianR = FilterType::New();
 gaussianR->SetInput(adaptorR);
 gaussianR->SetSigma(sigma);

 ImageAdaptorType::Pointer adaptorG = ImageAdaptorType::New();
 adaptorG->SelectNthElement(1);
 adaptorG->SetImage(reader->GetOutput());

 FilterType::Pointer gaussianG = FilterType::New();
 gaussianG->SetInput(adaptorG);
 gaussianG->SetSigma(sigma);

 ImageAdaptorType::Pointer adaptorB = ImageAdaptorType::New();
 adaptorB->SelectNthElement(2);
 adaptorB->SetImage(reader->GetOutput());

 FilterType::Pointer gaussianB = FilterType::New();
 gaussianB->SetInput(adaptorB);
 gaussianB->SetSigma(sigma);

 typedef itk::ComposeRGBImageFilter<
   ScalarImageType, ColorImageType >  ComposeFilterType;
 ComposeFilterType::Pointer composeFilter =
   ComposeFilterType::New();
 composeFilter->SetInput1(gaussianR->GetOutput());
 composeFilter->SetInput2(gaussianG->GetOutput());
 composeFilter->SetInput3(gaussianB->GetOutput());

 QuickView viewer;
 viewer.AddRGBImage(
   reader->GetOutput(),true,
   itksys::SystemTools::GetFilenameName(argv[1]));  

 std::stringstream desc;
 desc << "SmoothingRecursiveGaussian\n sigma = " << sigma;
 viewer.AddRGBImage(
   composeFilter->GetOutput(),
   true,
   desc.str());  

 viewer.Visualize();

 return EXIT_SUCCESS;

} </source>

CMakeLists.txt

<source lang="cmake"> cmake_minimum_required(VERSION 2.6)

PROJECT(SmoothingRecursiveGaussianImageFilter)

FIND_PACKAGE(ITK REQUIRED) INCLUDE(${ITK_USE_FILE})

ADD_EXECUTABLE(SmoothingRecursiveGaussianImageFilter SmoothingRecursiveGaussianImageFilter.cxx) TARGET_LINK_LIBRARIES(SmoothingRecursiveGaussianImageFilter ITKIO)

</source>