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/*=========================================================================
Program: Insight Segmentation & Registration Toolkit
Module: $RCSfile: itkDifferenceOfGaussiansGradientImageFilter.txx,v $
Language: C++
Date: $Date: 2003-09-10 14:28:46 $
Version: $Revision: 1.23 $
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 __itkDifferenceOfGaussiansGradientImageFilter_txx
#define __itkDifferenceOfGaussiansGradientImageFilter_txx
#include <math.h>
#include "itkProgressReporter.h"
#include "itkDifferenceOfGaussiansGradientImageFilter.h"
#include "itkImageRegionIterator.h"
namespace itk
{
template<typename TInputImage, typename TDataType>
DifferenceOfGaussiansGradientImageFilter< TInputImage, TDataType >
::DifferenceOfGaussiansGradientImageFilter()
{
itkDebugMacro(<< "DifferenceOfGaussiansGradientImageFilter::DifferenceOfGaussiansGradientImageFilter() called");
m_Width = 2;
}
template<typename TInputImage, typename TDataType>
void
DifferenceOfGaussiansGradientImageFilter< TInputImage, TDataType >
::GenerateData()
{
itkDebugMacro(<< "DifferenceOfGaussiansGradientImageFilter::GenerateData() called");
// Get the input and output pointers
typename Superclass::InputImagePointer inputPtr =
const_cast< TInputImage * >( this->GetInput(0));
typename Superclass::OutputImagePointer outputPtr = this->GetOutput(0);
// Make sure we're getting everything
inputPtr->SetRequestedRegionToLargestPossibleRegion();
// How big is the input image?
typename TInputImage::SizeType size = inputPtr->GetLargestPossibleRegion().GetSize();
// Create a region object native to the output image type
OutputImageRegionType outputRegion;
// Resize the output region
outputRegion.SetSize( size );
// Set the largest legal region size (i.e. the size of the whole image)
// to what we just defined
outputPtr->SetBufferedRegion( outputRegion );
outputPtr->Allocate();
// Create a progress reporter
ProgressReporter progress(this, 0, outputPtr->GetRequestedRegion().GetNumberOfPixels());
// Create an iterator that will walk the output region
typedef ImageRegionIterator<TOutputImage> OutputIterator;
OutputIterator outIt = OutputIterator(outputPtr,
outputPtr->GetRequestedRegion());
// Define a few indices that will be used to translate from an input pixel
// to an output pixel
typename TOutputImage::IndexType outputIndex;
typename TOutputImage::IndexType upperIndex;
typename TOutputImage::IndexType lowerIndex;
// walk the output image, and sample the input image
for ( ; !outIt.IsAtEnd(); ++outIt)
{
// determine the index of the output pixel
outputIndex = outIt.GetIndex();
// is the current index an acceptable distance from the edges
// of the image?
bool isValidGrad = true;
for (unsigned int i = 0; i < NDimensions; ++i)
{
const int width = static_cast<int>(m_Width);
const int sizeDifference =
static_cast<int>(size.m_Size[i]) - width;
if( !( (outputIndex[i] < sizeDifference ) &&
(outputIndex[i] >= width ) ) )
{
isValidGrad = false;
}
}
if (isValidGrad)
{
// We're in a safe position, so calculate the gradient for
// each dimension
for (unsigned int i = 0; i < NDimensions; i++)
{
// Build the indices for each pixel
for (unsigned int j = 0; j < NDimensions; j++)
{
if(j == i)
{
upperIndex[j] = outputIndex[j] + static_cast<typename TOutputImage::IndexValueType>(m_Width);
lowerIndex[j] = outputIndex[j] - static_cast<typename TOutputImage::IndexValueType>(m_Width);
}
else
{
upperIndex[j] = outputIndex[j];
lowerIndex[j] = outputIndex[j];
}
}
// Remember, output type is a covariant vector of TDataType
outputPtr->GetPixel(outputIndex)[i] =
inputPtr->GetPixel(upperIndex) - inputPtr->GetPixel(lowerIndex);
}
}
else // We're not in a safe position, gradient is zero
{
for (unsigned int i = 0; i < NDimensions; ++i)
outputPtr->GetPixel(outputIndex)[i] = 0.0;
}
progress.CompletedPixel();
}
itkDebugMacro(<< "DifferenceOfGaussiansGradientImageFilter::GenerateData() finished");
}
template<typename TInputImage, typename TDataType>
void
DifferenceOfGaussiansGradientImageFilter< TInputImage, TDataType >
::PrintSelf(std::ostream& os, Indent indent) const
{
Superclass::PrintSelf(os,indent);
os << indent << "Width is " << m_Width << std::endl;
}
} // end namespace
#endif
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