/usr/include/InsightToolkit/Algorithms/itkCurvatureFlowFunction.txx is in libinsighttoolkit3-dev 3.20.1-1.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 | /*=========================================================================
Program: Insight Segmentation & Registration Toolkit
Module: itkCurvatureFlowFunction.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 __itkCurvatureFlowFunction_txx
#define __itkCurvatureFlowFunction_txx
#include "itkCurvatureFlowFunction.h"
#include "vnl/vnl_math.h"
namespace itk {
/**
* Constructor
*/
template<class TImage>
CurvatureFlowFunction<TImage>
::CurvatureFlowFunction()
{
RadiusType r;
unsigned int j;
for( j = 0; j < ImageDimension; j++ )
{
r[j] = 1;
}
this->SetRadius(r);
m_TimeStep = 0.05f;
}
/**
* Compute the global time step
*/
template<class TImage>
typename CurvatureFlowFunction<TImage>::TimeStepType
CurvatureFlowFunction<TImage>
::ComputeGlobalTimeStep( void *itkNotUsed(gd) ) const
{
return this->GetTimeStep();
// \todo compute timestep based on CFL condition
#if 0
GlobalDataStruct *globalData = (GlobalDataStruct *)gd;
TimeStepType dt;
if ( globalData->m_MaxChange > 0.0 )
{
dt = 1.0 / globalData->m_MaxChange;
}
else
{
dt = 0.0;
}
return dt;
#endif
}
/**
* Update the solution at pixels which lies on the data boundary.
*/
template<class TImage>
typename CurvatureFlowFunction<TImage>::PixelType
CurvatureFlowFunction<TImage>
::ComputeUpdate(const NeighborhoodType &it, void * itkNotUsed(gd),
const FloatOffsetType& itkNotUsed(offset))
{
PixelRealType firstderiv[ImageDimension];
PixelRealType secderiv[ImageDimension];
PixelRealType crossderiv[ImageDimension][ImageDimension];
unsigned long center;
unsigned long stride[ImageDimension];
unsigned int i,j;
const NeighborhoodScalesType neighborhoodScales = this->ComputeNeighborhoodScales();
// get the center pixel position
center = it.Size() / 2;
// cache the stride for each dimension
for( i = 0; i < ImageDimension; i++ )
{
stride[i] = it.GetStride( (unsigned long) i );
}
PixelRealType magnitudeSqr = 0.0;
for( i = 0; i < ImageDimension; i++ )
{
// compute first order derivatives
firstderiv[i] = 0.5 * ( it.GetPixel(center + stride[i]) -
it.GetPixel(center - stride[i]) ) * neighborhoodScales[i];
// compute second order derivatives
secderiv[i] = ( it.GetPixel(center + stride[i]) -
2 * it.GetPixel(center) + it.GetPixel( center - stride[i] ) ) * vnl_math_sqr( neighborhoodScales[i] );
// compute cross derivatives
for( j = i + 1; j < ImageDimension; j++ )
{
crossderiv[i][j] = 0.25 * (
it.GetPixel( center - stride[i] - stride[j] )
- it.GetPixel( center - stride[i] + stride[j] )
- it.GetPixel( center + stride[i] - stride[j] )
+ it.GetPixel( center + stride[i] + stride[j] ) )
* neighborhoodScales[i] * neighborhoodScales[j];
}
// accumlate the gradient magnitude squared
magnitudeSqr += vnl_math_sqr( (double)firstderiv[i] );
}
if ( magnitudeSqr < 1e-9 )
{
return NumericTraits<PixelType>::Zero;
}
// compute the update value = mean curvature * magnitude
PixelRealType update = 0.0;
PixelRealType temp;
// accumulate dx^2 * (dyy + dzz) terms
for( i = 0; i < ImageDimension; i++ )
{
temp = 0.0;
for( j = 0; j < ImageDimension; j++ )
{
if( j == i ) continue;
temp += secderiv[j];
}
update += temp * vnl_math_sqr( (double)firstderiv[i] );
}
// accumlate -2 * dx * dy * dxy terms
for( i = 0; i < ImageDimension; i++ )
{
for( j = i + 1; j < ImageDimension; j++ )
{
update -= 2 * firstderiv[i] * firstderiv[j] *
crossderiv[i][j];
}
}
update /= magnitudeSqr;
// \todo compute timestep based on CFL condition
#if 0
GlobalDataStruct *globalData = (GlobalDataStruct *)gd;
globalData->m_MaxChange =
vnl_math_max( globalData->m_MaxChange, vnl_math_abs(update) );
#endif
return static_cast<PixelType>(update);
}
} // end namespace itk
#endif
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