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/*=========================================================================
*
* Copyright Insight Software Consortium
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0.txt
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*=========================================================================*/
#ifndef itkMedianImageFilter_hxx
#define itkMedianImageFilter_hxx
#include "itkMedianImageFilter.h"
#include "itkConstNeighborhoodIterator.h"
#include "itkNeighborhoodInnerProduct.h"
#include "itkImageRegionIterator.h"
#include "itkNeighborhoodAlgorithm.h"
#include "itkOffset.h"
#include "itkProgressReporter.h"
#include <vector>
#include <algorithm>
namespace itk
{
template< typename TInputImage, typename TOutputImage >
MedianImageFilter< TInputImage, TOutputImage >
::MedianImageFilter()
{}
template< typename TInputImage, typename TOutputImage >
void
MedianImageFilter< TInputImage, TOutputImage >
::ThreadedGenerateData(const OutputImageRegionType & outputRegionForThread,
ThreadIdType 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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