ITK/Examples/Broken/EdgesAndGradients/CannyEdgeDetectionImageFilter

How to set a reasonable Threshold for the output edges?

CannyEdgeDetectionImageFilter.cxx

<source lang="cpp">

1. include "itkImage.h"
2. include "itkImageFileReader.h"
3. include "itkRescaleIntensityImageFilter.h"
4. include "itkCastImageFilter.h"
5. include "itkCannyEdgeDetectionImageFilter.h"

1. include "QuickView.h"

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

 if(argc < 2)
   {
   std::cerr << "Usage: " << argv[0]
             << " Filename [variance lower_threshold upper_threshold]"
             << std::endl;
   return EXIT_FAILURE;
   }

 double variance = 2.0;
 double upperThreshold = 0.0;
 double lowerThreshold = 0.0;
 if (argc > 2)
   {
   variance = atof(argv[2]);
   }
 if (argc > 3)
   {
   lowerThreshold = atof(argv[3]);
   }
 if (argc > 4)
   {
   upperThreshold = atof(argv[4]);
   }

 typedef itk::Image<double, 2>  DoubleImageType;

 typedef itk::ImageFileReader<DoubleImageType> ReaderType;
 ReaderType::Pointer reader = ReaderType::New();
 reader->SetFileName(argv[1]);

 typedef itk::CannyEdgeDetectionImageFilter <DoubleImageType, DoubleImageType>
   CannyEdgeDetectionImageFilterType;

 CannyEdgeDetectionImageFilterType::Pointer cannyFilter
   = CannyEdgeDetectionImageFilterType::New();
 cannyFilter->SetInput(reader->GetOutput());
 cannyFilter->SetVariance( variance );
 cannyFilter->SetUpperThreshold( upperThreshold );
 cannyFilter->SetLowerThreshold( lowerThreshold );

 QuickView viewer;
 viewer.AddImage<DoubleImageType>(reader->GetOutput());
 viewer.AddImage<DoubleImageType>(cannyFilter->GetOutput());
 viewer.Visualize();

 return EXIT_SUCCESS;

} </source>

CMakeLists.txt

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

PROJECT(CannyEdgeDetectionImageFilter)

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(CannyEdgeDetectionImageFilter CannyEdgeDetectionImageFilter.cxx) TARGET_LINK_LIBRARIES(CannyEdgeDetectionImageFilter vtkHybrid ITKBasicFilters ITKCommon ITKIO)

</source>