ITK/Examples/EdgesAndGradients/DerivativeImageFilter: Difference between revisions

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<div class="floatright">[[File:ITK_Examples_Baseline_EdgesAndGradients_TestDerivativeImageFilter.png]]</div>
{{warning|1=The media wiki content on this page is no longer maintained.  The examples presented on the https://itk.org/Wiki/*  pages likely require ITK version 4.13 or earlier releases.  In many cases, the examples on this page no longer conform to the best practices for modern ITK versions.
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==
[https://itk.org/ITKExamples[ITK Sphinx Examples]]
<source lang="cpp">
#include "itkImage.h"
#include "itkImageFileReader.h"
#include "itkImageFileWriter.h"
#include "itkRescaleIntensityImageFilter.h"
#include "itkDerivativeImageFilter.h"
 
#include <itkImageToVTKImageFilter.h>
 
#include "vtkImageViewer.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkSmartPointer.h"
#include "vtkImageActor.h"
#include "vtkInteractorStyleImage.h"
#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>

Latest revision as of 14:37, 4 June 2019

Warning: The media wiki content on this page is no longer maintained. The examples presented on the https://itk.org/Wiki/* pages likely require ITK version 4.13 or earlier releases. In many cases, the examples on this page no longer conform to the best practices for modern ITK versions.

[ITK Sphinx Examples]