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/*=========================================================================
Program: Insight Segmentation & Registration Toolkit
Module: $RCSfile: itkImageToHistogramGeneratorTest.cxx,v $
Language: C++
Date: $Date: 2005-02-08 03:18:41 $
Version: $Revision: 1.4 $
Copyright (c) Insight Software Consortium. All rights reserved.
See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notices for more information.
=========================================================================*/
#if defined(_MSC_VER)
#pragma warning ( disable : 4786 )
#endif
#include "itkImageToHistogramGenerator.h"
#include "itkImage.h"
#include "itkRGBPixel.h"
#include "itkImageRegionIteratorWithIndex.h"
int itkImageToHistogramGeneratorTest( int , char * [] )
{
typedef unsigned char PixelComponentType;
typedef itk::RGBPixel< PixelComponentType > RGBPixelType;
const unsigned int Dimension = 3;
typedef itk::Image< RGBPixelType, Dimension > RGBImageType;
RGBImageType::Pointer image = RGBImageType::New();
RGBImageType::RegionType region;
RGBImageType::SizeType size;
RGBImageType::IndexType start;
size[0] = 127;
size[1] = 127;
size[2] = 127;
start[0] = 0;
start[1] = 0;
start[2] = 0;
region.SetIndex( start );
region.SetSize( size );
image->SetRegions( region );
image->Allocate();
// Now fill up the image will all the combinations of RGB
// values from 0-255 on each channel.
itk::ImageRegionIteratorWithIndex< RGBImageType > it( image, region );
it.GoToBegin();
RGBPixelType pixel;
RGBImageType::IndexType index;
while( !it.IsAtEnd() )
{
index = it.GetIndex();
pixel.SetRed( index[0] );
pixel.SetGreen( index[1] );
pixel.SetBlue( index[2] );
it.Set( pixel );
++it;
}
typedef itk::Statistics::ImageToHistogramGenerator<
RGBImageType
> HistogramGeneratorType;
typedef HistogramGeneratorType::SizeType HistogramSizeType;
HistogramSizeType hsize;
hsize[0] = 127; // number of bins for the Red channel
hsize[1] = 1; // number of bins for the Green channel
hsize[2] = 1; // number of bins for the Blue channel
HistogramGeneratorType::Pointer histogramGenerator = HistogramGeneratorType::New();
histogramGenerator->SetInput( image );
histogramGenerator->SetNumberOfBins( hsize );
histogramGenerator->SetMarginalScale( 10.0 );
histogramGenerator->Compute();
typedef HistogramGeneratorType::HistogramType HistogramType;
const HistogramType * histogram = histogramGenerator->GetOutput();
const unsigned int histogramSize = histogram->Size();
std::cout << "Histogram size " << histogramSize << std::endl;
unsigned int channel = 0; // red channel
std::cout << "Histogram of the red component" << std::endl;
const unsigned int expectedFrequency = 127 * 127;
for( unsigned int bin=0; bin < histogramSize; bin++ )
{
if( histogram->GetFrequency( bin, channel ) != expectedFrequency )
{
std::cerr << "Error in bin= " << bin << " channel = " << channel << std::endl;
std::cerr << "Frequency was= " << histogram->GetFrequency( bin, channel ) << " Instead of the expected " << expectedFrequency << std::endl;
return EXIT_FAILURE;
}
}
// Now compute the histogram for the Green component
hsize[0] = 1; // number of bins for the Red channel
hsize[1] = 127; // number of bins for the Green channel
hsize[2] = 1; // number of bins for the Blue channel
histogramGenerator->SetNumberOfBins( hsize );
histogramGenerator->SetMarginalScale( 10.0 );
histogramGenerator->Compute();
channel = 1; // green channel
std::cout << "Histogram of the green component" << std::endl;
for( unsigned int bin=0; bin < histogramSize; bin++ )
{
std::cout << "bin = " << bin << " frequency = ";
std::cout << histogram->GetFrequency( bin, channel ) << std::endl;
}
// Now compute the histogram for the Blue component
size[0] = 1; // number of bins for the Red channel
size[1] = 1; // number of bins for the Green channel
size[2] = 127; // number of bins for the Blue channel
histogramGenerator->SetNumberOfBins( size );
histogramGenerator->SetMarginalScale( 10.0 );
histogramGenerator->Compute();
channel = 2; // blue channel
std::cout << "Histogram of the blue component" << std::endl;
for( unsigned int bin=0; bin < histogramSize; bin++ )
{
std::cout << "bin = " << bin << " frequency = ";
std::cout << histogram->GetFrequency( bin, channel ) << std::endl;
}
// Now compute the joint histogram for the three components
hsize[0] = 127; // number of bins for the Red channel
hsize[1] = 127; // number of bins for the Green channel
hsize[2] = 127; // number of bins for the Blue channel
histogramGenerator->SetNumberOfBins( hsize );
histogramGenerator->SetMarginalScale( 10.0 );
histogramGenerator->Compute();
return EXIT_SUCCESS;
}
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