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/*=========================================================================
Program: Insight Segmentation & Registration Toolkit
Module: itkOptMedianImageFilter.txx
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.
=========================================================================*/
#ifndef __itkOptMedianImageFilter_txx
#define __itkOptMedianImageFilter_txx
#include "itkMedianImageFilter.h"
#include "itkConstNeighborhoodIterator.h"
#include "itkNeighborhoodInnerProduct.h"
#include "itkImageRegionIterator.h"
#include "itkNeighborhoodAlgorithm.h"
#include "itkZeroFluxNeumannBoundaryCondition.h"
#include "itkOffset.h"
#include "itkProgressReporter.h"
#include <vector>
#include <algorithm>
namespace itk
{
template <class TInputImage, class TOutputImage>
MedianImageFilter<TInputImage, TOutputImage>
::MedianImageFilter()
{
}
template< class TInputImage, class TOutputImage>
void
MedianImageFilter< TInputImage, TOutputImage>
::ThreadedGenerateData(const OutputImageRegionType& outputRegionForThread,
int threadId)
{
// Allocate output
typename OutputImageType::Pointer output = this->GetOutput();
typename InputImageType::ConstPointer input = this->GetInput();
// Find the data-set boundary "faces"
NeighborhoodAlgorithm::ImageBoundaryFacesCalculator<InputImageType> bC;
typename NeighborhoodAlgorithm::ImageBoundaryFacesCalculator<InputImageType>::FaceListType
faceList = bC(input, outputRegionForThread, this->GetRadius());
// support progress methods/callbacks
ProgressReporter progress(this, threadId, outputRegionForThread.GetNumberOfPixels());
// All of our neighborhoods have an odd number of pixels, so there is
// always a median index (if there where an even number of pixels
// in the neighborhood we have to average the middle two values).
ZeroFluxNeumannBoundaryCondition<InputImageType> nbc;
std::vector<InputPixelType> pixels;
// Process each of the boundary faces. These are N-d regions which border
// the edge of the buffer.
for ( typename NeighborhoodAlgorithm::ImageBoundaryFacesCalculator<InputImageType>::FaceListType::iterator
fit=faceList.begin(); fit != faceList.end(); ++fit)
{
ImageRegionIterator<OutputImageType> it = ImageRegionIterator<OutputImageType>(output, *fit);
ConstNeighborhoodIterator<InputImageType> bit =
ConstNeighborhoodIterator<InputImageType>(this->GetRadius(), input, *fit);
bit.OverrideBoundaryCondition(&nbc);
bit.GoToBegin();
const unsigned int neighborhoodSize = bit.Size();
const unsigned int medianPosition = neighborhoodSize / 2;
while ( ! bit.IsAtEnd() )
{
// collect all the pixels in the neighborhood, note that we use
// GetPixel on the NeighborhoodIterator to honor the boundary conditions
pixels.resize(neighborhoodSize);
for (unsigned int i = 0; i < neighborhoodSize; ++i)
{
pixels[i]=( bit.GetPixel(i) );
}
// get the median value
const typename std::vector<InputPixelType>::iterator medianIterator = pixels.begin() + medianPosition;
std::nth_element(pixels.begin(), medianIterator, pixels.end());
it.Set( static_cast<typename OutputImageType::PixelType> (*medianIterator) );
++bit;
++it;
progress.CompletedPixel();
}
}
}
} // end namespace itk
#endif
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