/usr/include/ITK-4.5/itkVectorLinearInterpolateImageFunction.hxx is in libinsighttoolkit4-dev 4.5.0-3.
This file is owned by root:root, with mode 0o644.
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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 __itkVectorLinearInterpolateImageFunction_hxx
#define __itkVectorLinearInterpolateImageFunction_hxx
#include "itkVectorLinearInterpolateImageFunction.h"
#include "vnl/vnl_math.h"
namespace itk
{
/**
* Define the number of neighbors
*/
template< typename TInputImage, typename TCoordRep >
const unsigned long
VectorLinearInterpolateImageFunction< TInputImage, TCoordRep >
::m_Neighbors = 1 << TInputImage::ImageDimension;
/**
* Constructor
*/
template< typename TInputImage, typename TCoordRep >
VectorLinearInterpolateImageFunction< TInputImage, TCoordRep >
::VectorLinearInterpolateImageFunction()
{}
/**
* PrintSelf
*/
template< typename TInputImage, typename TCoordRep >
void
VectorLinearInterpolateImageFunction< TInputImage, TCoordRep >
::PrintSelf(std::ostream & os, Indent indent) const
{
this->Superclass::PrintSelf(os, indent);
}
/**
* Evaluate at image index position
*/
template< typename TInputImage, typename TCoordRep >
typename VectorLinearInterpolateImageFunction< TInputImage, TCoordRep >
::OutputType
VectorLinearInterpolateImageFunction< TInputImage, TCoordRep >
::EvaluateAtContinuousIndex(
const ContinuousIndexType & index) const
{
/**
* Compute base index = closet index below point
* Compute distance from point to base index
*/
IndexType baseIndex;
InternalComputationType distance[ImageDimension];
const TInputImage * const inputImgPtr=this->GetInputImage();
for (unsigned int dim = 0; dim < ImageDimension; ++dim )
{
baseIndex[dim] = Math::Floor< IndexValueType >(index[dim]);
distance[dim] = index[dim] - static_cast< InternalComputationType >( baseIndex[dim] );
}
/**
* Interpolated value is the weighted sum of each of the surrounding
* neighbors. The weight for each neighbor is the fraction overlap
* of the neighbor pixel with respect to a pixel centered on point.
*/
OutputType output;
output.Fill(0.0);
typedef typename NumericTraits< PixelType >::ScalarRealType ScalarRealType;
ScalarRealType totalOverlap = NumericTraits< ScalarRealType >::Zero;
for ( unsigned int counter = 0; counter < m_Neighbors; ++counter )
{
InternalComputationType overlap = 1.0; // fraction overlap
unsigned int upper = counter; // each bit indicates upper/lower neighbour
IndexType neighIndex;
// get neighbor index and overlap fraction
for ( unsigned int dim = 0; dim < ImageDimension; ++dim )
{
if ( upper & 1 )
{
neighIndex[dim] = baseIndex[dim] + 1;
// Take care of the case where the pixel is just
// in the outer upper boundary of the image grid.
if ( neighIndex[dim] > this->m_EndIndex[dim] )
{
neighIndex[dim] = this->m_EndIndex[dim];
}
overlap *= distance[dim];
}
else
{
neighIndex[dim] = baseIndex[dim];
// Take care of the case where the pixel is just
// in the outer lower boundary of the image grid.
if ( neighIndex[dim] < this->m_StartIndex[dim] )
{
neighIndex[dim] = this->m_StartIndex[dim];
}
overlap *= 1.0 - distance[dim];
}
upper >>= 1;
}
// get neighbor value only if overlap is not zero
if ( overlap )
{
const PixelType & input = inputImgPtr->GetPixel(neighIndex);
for ( unsigned int k = 0; k < Dimension; ++k )
{
output[k] += overlap * static_cast< InternalComputationType >( input[k] );
}
totalOverlap += overlap;
}
if ( totalOverlap == 1.0 )
{
// finished
break;
}
}
return ( output );
}
} // end namespace itk
#endif
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