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/*=========================================================================
Program: Insight Segmentation & Registration Toolkit
Module: itkFFTShiftImageFilter.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 __itkFFTShiftImageFilter_txx
#define __itkFFTShiftImageFilter_txx
#include "itkFFTShiftImageFilter.h"
#include "itkNumericTraits.h"
#include "itkProgressReporter.h"
#include "itkImageRegionIteratorWithIndex.h"
namespace itk {
template <class TInputImage, class TOutputImage>
FFTShiftImageFilter<TInputImage, TOutputImage>
::FFTShiftImageFilter()
{
m_Inverse = false;
}
template <class TInputImage, class TOutputImage>
void
FFTShiftImageFilter<TInputImage, TOutputImage>
::GenerateInputRequestedRegion()
{
// call the superclass' implementation of this method
Superclass::GenerateInputRequestedRegion();
// We need all the input.
InputImagePointer input = const_cast<InputImageType *>(this->GetInput());
if ( !input )
{ return; }
input->SetRequestedRegion( input->GetLargestPossibleRegion() );
}
template<class TInputImage, class TOutputImage>
void
FFTShiftImageFilter<TInputImage, TOutputImage>
::ThreadedGenerateData(const OutputImageRegionType& outputRegionForThread,
int threadId)
{
// setup the progress reporter
ProgressReporter progress( this, threadId, outputRegionForThread.GetNumberOfPixels() );
// the index and size of the image needed to compute the shift
const IndexType oIdx = this->GetOutput()->GetLargestPossibleRegion().GetIndex();
const SizeType oSize = this->GetOutput()->GetLargestPossibleRegion().GetSize();
// the size of the segments for all axes
SizeType seg1Size;
SizeType seg2Size;
// the center pixel is not computed the same way for the inverse shift in
// case the size is odd, to restore the same image as before the shift
for( int i=0; i<ImageDimension; i++)
{
if( oSize[i] % 2 == 1 )
{
if( !m_Inverse )
{
seg1Size[i] = oSize[i] / 2 + 1;
seg2Size[i] = oSize[i] / 2;
}
else
{
seg1Size[i] = oSize[i] / 2;
seg2Size[i] = oSize[i] / 2 + 1;
}
}
else
{
seg1Size[i] = oSize[i] / 2;
seg2Size[i] = oSize[i] / 2;
}
}
// now iterate over the pixels of the output region for this thread
ImageRegionIteratorWithIndex<OutputImageType> oIt( this->GetOutput(), outputRegionForThread );
for( oIt.GoToBegin(); !oIt.IsAtEnd(); ++oIt )
{
IndexType idx = oIt.GetIndex();
for( int i=0; i<ImageDimension; i++ )
{
if( idx[i] < (int)(oIdx[i] + seg2Size[i]) )
{
idx[i] = idx[i] + seg1Size[i];
}
else
{
idx[i] = idx[i] - seg2Size[i];
}
}
oIt.Set( static_cast< OutputImagePixelType >( this->GetInput()->GetPixel( idx ) ) );
progress.CompletedPixel();
}
}
template<class TInputImage, class TOutputImage>
void
FFTShiftImageFilter<TInputImage, TOutputImage>
::PrintSelf(std::ostream &os, Indent indent) const
{
Superclass::PrintSelf(os, indent);
os << indent << "Inverse: " << m_Inverse << std::endl;
}
}// end namespace itk
#endif
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