[Insight-users] Problem computing coocurence matrix

[Christophe Lay]

Hello

I am working on coocurence matrices in the aim to extract texture
properties from an image (entropy, energy, contrast and correlation). I
use the following classes :
"ScalarImageToGreyLevelCooccurrenceMatrixGenerator" and
"GreyLevelCooccurrenceMatrixTextureCoefficientsCalculator" to obtain a
histogram (cf code). My program works but it gives me the same strange
results with different images. I would know if my program seems correct.

Results:
   Contrast = 3.33997e+150
   Correlation = 6.9641e+252
   Energy = 1.32722e+180
   Entropy = 4.05398e+180

The source code is added at the end of the message.

Thank you
  
-- 
Christophe LAY
Stagiaire
Bureau N12, Bât. FERMAT
Tel interne : 83 201
CNES - DCT/SI/AP - BPI 1219
18, avenue Edouard Belin
31401 Toulouse Cedex 09 - France


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#include "itkExceptionObject.h"
#include "otbImage.h"
#include <iostream>

#include "otbImageFileWriter.h"
#include "itkImageRegionIterator.h"

#include "otbImageFileReader.h"
#include "itkScalarImageToGreyLevelCooccurrenceMatrixGenerator.h"
#include "itkGreyLevelCooccurrenceMatrixTextureCoefficientsCalculator.h"

int main(int argc, char ** argv )
{
	const char * inputFilename  = argv[1];

	typedef unsigned char     InputPixelType;
	const   unsigned int      Dimension = 2;	
	typedef itk::Image<InputPixelType,Dimension> InputImageType;
	typedef itk::ImageFileReader<InputImageType> ReaderType;
	
	typedef
itk::Statistics::ScalarImageToGreyLevelCooccurrenceMatrixGenerator<InputImageType> GLCMGeneratorType;
	typedef
itk::Statistics::GreyLevelCooccurrenceMatrixTextureCoefficientsCalculator<GLCMGeneratorType::HistogramType> TexCalcType;
	
	ReaderType::Pointer reader = ReaderType::New();
	reader->SetFileName(inputFilename);
	reader->Update();

	InputImageType::Pointer block = InputImageType::New();
	block->SetRegions(reader->GetOutput()->GetRequestedRegion());
	block->Allocate();

	GLCMGeneratorType::Pointer glcm = GLCMGeneratorType::New();
	glcm->SetInput(block);
	InputImageType::OffsetType offset = {1,0};
	glcm->SetOffset(offset);
	glcm->SetNumberOfBinsPerAxis(256);
	
	glcm->Compute();

	TexCalcType::Pointer texCalc = TexCalcType::New();
	texCalc->SetHistogram(glcm->GetOutput());
	
	double contrast = texCalc->GetInertia();
	double correlation = texCalc->GetCorrelation();
	double energy = texCalc->GetEnergy();
	double entropy = texCalc->GetEntropy();
	std::cout << "   Contrast = " << contrast << std::endl;
	std::cout << "   Correlation = " <<  correlation<< std::endl;
	std::cout << "   Energy = " <<energy << std::endl;
	std::cout << "   Entropy = " << entropy << std::endl;

  	return EXIT_SUCCESS;
}

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