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/*=========================================================================
Program: Insight Segmentation & Registration Toolkit
Module: ListSampleToHistogramGenerator.cxx
Language: C++
Date: $Date$
Version: $Revision$
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
// Software Guide : BeginLatex
//
// \index{Statistics!Convert ListSample to Histogram}
// \index{itk::Statistics::List\-Sample\-To\-Histogram\-Generator}
//
// In previous sections (Section~\ref{sec:ListSampleToHistogramFilter} we
// described how to import data from a \subdoxygen{Statistics}{ListSample} to
// a \subdoxygen{Statistics}{Histogram}. An alternative way of creating a
// histogram is to use
// \subdoxygen{Statistics}{ListSampleToHistogramGenerator}. With this
// generator, we only provide the size of the histogram and the type of the
// measurement vectors in the histogram. The generator will automatically
// find the lower and upper space bound and create equal interval bins in the
// histogram.
//
// We use a ListSample object as the input for the filter. We include the
// header files for the ListSample, Histogram, and the filter itself.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
#include "itkListSample.h"
#include "itkHistogram.h"
#include "itkListSampleToHistogramGenerator.h"
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// We need another header for measurement vectors. We are going to use
// the \doxygen{Vector} class which is a subclass of the \doxygen{FixedArray}
// in this example.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
#include "itkVector.h"
// Software Guide : EndCodeSnippet
int main()
{
// Software Guide : BeginLatex
//
// The following code snippet will create a ListSample object
// with two-component int measurement vectors and put the measurement
// vectors: [1,1] - 1 time, [2,2] - 2 times, [3,3] - 3 times, [4,4] -
// 4 times, [5,5] - 5 times into the ListSample.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
typedef int MeasurementType;
const unsigned int MeasurementVectorLength = 2;
typedef itk::Vector< MeasurementType , MeasurementVectorLength >
MeasurementVectorType;
typedef itk::Statistics::ListSample< MeasurementVectorType > ListSampleType;
ListSampleType::Pointer listSample = ListSampleType::New();
listSample->SetMeasurementVectorSize( MeasurementVectorLength );
MeasurementVectorType mv;
for ( unsigned int i = 1 ; i < 6 ; i++ )
{
for ( unsigned int j = 0 ; j < 2 ; j++ )
{
mv[j] = ( MeasurementType ) i;
}
for ( unsigned int j = 0 ; j < i ; j++ )
{
listSample->PushBack(mv);
}
}
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The ListSampleToHistogramGenerator will find the lower and upper bound
// from the input sample and create equal interval bins. Since a Histogram
// object does not include the upper bound value and we want to include
// [5,5] measurement vector, we increase the upper-bound by the calculated
// bin interval/10.0 (divider). The divider is set by the
// \code{SetMarginalScale(float)} method. If you want to create a
// non-uniform histogram, you should use the ListSampleToHistogramFilter
// (see Section~\ref{sec:ListSampleToHistogramFilter}). The filter does not
// create a Histogram object. Instead, users should create a
// Histogram object with varying intervals and use the filter to
// fill the Histogram objects with the measurement vectors from a
// ListSample object.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
typedef float HistogramMeasurementType;
typedef itk::Statistics::ListSampleToHistogramGenerator< ListSampleType,
HistogramMeasurementType,
itk::Statistics::DenseFrequencyContainer,
MeasurementVectorLength > GeneratorType;
GeneratorType::Pointer generator = GeneratorType::New();
GeneratorType::HistogramType::SizeType size;
size.Fill(5);
generator->SetListSample( listSample );
generator->SetNumberOfBins( size );
generator->SetMarginalScale( 10.0 );
generator->Update();
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The following code prints out the content of the resulting
// histogram.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
GeneratorType::HistogramType::ConstPointer histogram = generator->GetOutput();
GeneratorType::HistogramType::ConstIterator iter = histogram->Begin();
while ( iter != histogram->End() )
{
std::cout << "Measurement vectors = " << iter.GetMeasurementVector()
<< " frequency = " << iter.GetFrequency() << std::endl;
++iter;
}
std::cout << "Size = " << histogram->Size() << std::endl;
std::cout << "Total frequency = "
<< histogram->GetTotalFrequency() << std::endl;
// Software Guide : EndCodeSnippet
return 0;
}
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