ITK/Examples/EdgesAndGradients/DerivativeImageFilter: Difference between revisions

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<div class="floatright">[[File:ITK_Examples_Baseline_EdgesAndGradients_TestDerivativeImageFilter.png]]</div>
This example demonstrates how to compute the derivative of an image in a specified axis-aligned direction. The original image and its x derivative are displayed on the screen.
This example demonstrates how to compute the derivative of an image in a specified axis-aligned direction. The original image and its x derivative are displayed on the screen.



Revision as of 00:44, 12 December 2010

ITK Examples Baseline EdgesAndGradients TestDerivativeImageFilter.png

This example demonstrates how to compute the derivative of an image in a specified axis-aligned direction. The original image and its x derivative are displayed on the screen.

DerivativeImageFilter.cxx

<source lang="cpp">

  1. include "itkImage.h"
  2. include "itkImageFileReader.h"
  3. include "itkImageFileWriter.h"
  4. include "itkRescaleIntensityImageFilter.h"
  5. include "itkDerivativeImageFilter.h"
  1. include <itkImageToVTKImageFilter.h>
  1. include "vtkImageViewer.h"
  2. include "vtkRenderWindowInteractor.h"
  3. include "vtkSmartPointer.h"
  4. include "vtkImageActor.h"
  5. include "vtkInteractorStyleImage.h"
  6. include "vtkRenderer.h"

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

 // Verify command line arguments
 if( argc < 2 )
   {
   std::cerr << "Usage: " << std::endl;
   std::cerr << argv[0] << "inputImageFile" << std::endl;
   return EXIT_FAILURE;
   }
 // Parse command line arguments
 std::string inputFilename = argv[1];
 // Setup types
 typedef itk::Image< float,  2 >   FloatImageType;
 typedef itk::Image< unsigned char, 2 >   UnsignedCharImageType;
 typedef itk::ImageFileReader< UnsignedCharImageType >  readerType;
 typedef itk::DerivativeImageFilter<

UnsignedCharImageType, FloatImageType > filterType;

 // Create and setup a reader
 readerType::Pointer reader = readerType::New();
 reader->SetFileName( inputFilename.c_str() );
 // Create and setup a derivative filter
 filterType::Pointer derivativeFilter = filterType::New();
 derivativeFilter->SetInput( reader->GetOutput() );
 derivativeFilter->SetDirection(0); // "x" axis
 derivativeFilter->Update();
 // To visualize the derivative, we must rescale the values
 // to a reasonable range
 typedef itk::RescaleIntensityImageFilter<

FloatImageType, UnsignedCharImageType > rescaleFilterType;

 rescaleFilterType::Pointer rescaler = rescaleFilterType::New();
 rescaler->SetOutputMinimum(0);
 rescaler->SetOutputMaximum(255);
 rescaler->SetInput( derivativeFilter->GetOutput() );
 rescaler->Update();
 typedef itk::ImageToVTKImageFilter<UnsignedCharImageType> ConnectorType;
 ConnectorType::Pointer originalConnector = ConnectorType::New();
 originalConnector->SetInput(reader->GetOutput());
 vtkSmartPointer<vtkImageActor> originalActor =
   vtkSmartPointer<vtkImageActor>::New();
 originalActor->SetInput(originalConnector->GetOutput());
 typedef itk::ImageToVTKImageFilter<UnsignedCharImageType> ConnectorType;
 ConnectorType::Pointer derivativeConnector = ConnectorType::New();
 derivativeConnector->SetInput(rescaler->GetOutput());
 vtkSmartPointer<vtkImageActor> derivativeActor =
   vtkSmartPointer<vtkImageActor>::New();
 derivativeActor->SetInput(derivativeConnector->GetOutput());
 // 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};
 // Setup both renderers
 vtkSmartPointer<vtkRenderWindow> renderWindow =
   vtkSmartPointer<vtkRenderWindow>::New();
 renderWindow->SetSize(600,300);
 vtkSmartPointer<vtkRenderer> leftRenderer =
   vtkSmartPointer<vtkRenderer>::New();
 renderWindow->AddRenderer(leftRenderer);
 leftRenderer->SetViewport(leftViewport);
 vtkSmartPointer<vtkRenderer> rightRenderer =
   vtkSmartPointer<vtkRenderer>::New();
 renderWindow->AddRenderer(rightRenderer);
 rightRenderer->SetViewport(rightViewport);
 leftRenderer->AddActor(originalActor);
 rightRenderer->AddActor(derivativeActor);
 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;

} </source>

CMakeLists.txt

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

PROJECT(DerivativeImageFilter)

include_directories(/home/doriad/src/ITK/Wrapping/WrapITK/ExternalProjects/ItkVtkGlue/src/)

FIND_PACKAGE(VTK REQUIRED) INCLUDE(${VTK_USE_FILE})

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

ADD_EXECUTABLE(DerivativeImageFilter DerivativeImageFilter.cxx) TARGET_LINK_LIBRARIES(DerivativeImageFilter vtkHybrid ITKBasicFilters ITKIO ITKCommon)

</source>