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/*=========================================================================
Program: Insight Segmentation & Registration Toolkit
Module: $RCSfile: itkApproximateSignedDistanceMapImageFilter.txx,v $
Language: C++
Date: $Date: 2005-09-13 13:30:49 $
Version: $Revision: 1.2 $
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 _itkApproximateSignedDistanceMapImageFilter_txx
#define _itkApproximateSignedDistanceMapImageFilter_txx
#include "itkApproximateSignedDistanceMapImageFilter.h"
#include "itkNumericTraits.h"
#include "itkImageRegionIterator.h"
#include "itkProgressAccumulator.h"
#include "vcl_cmath.h"
namespace itk {
/*
* Default constructor.
*/
template <class TInputImage, class TOutputImage>
ApproximateSignedDistanceMapImageFilter<TInputImage,TOutputImage>
::ApproximateSignedDistanceMapImageFilter() :
m_IsoContourFilter( IsoContourType::New() ),
m_ChamferFilter( ChamferType::New() ),
m_InsideValue( NumericTraits<InputPixelType>::min() ),
m_OutsideValue( NumericTraits<InputPixelType>::max() )
{
// I'm not setting any of the ReleaseDataFlag values for the mini-pipeline
// filters. Should I be?
}
/*
* Generate Data.
*/
template <class TInputImage, class TOutputImage>
void
ApproximateSignedDistanceMapImageFilter<TInputImage,TOutputImage>
::GenerateData()
{
// calculate the largest possible distance in the output image.
// this maximum is the distance from one corner of the image to the other.
OutputSizeType outputSize = this->GetOutput()->GetRequestedRegion().GetSize();
OutputSizeValueType maximumDistance = 0;
for (unsigned int i = 0; i < InputImageDimension; i++)
{
maximumDistance += outputSize[i]*outputSize[i];
}
// cast to float and back because there's no sqrt defined for unsigned long double,
// which is the general SizeValueType.
maximumDistance =
static_cast<OutputSizeValueType>(vcl_sqrt(static_cast<float>(maximumDistance)));
// Allocate the output
this->AllocateOutputs();
// Create a process accumulator for tracking the progress of this minipipeline
ProgressAccumulator::Pointer progress = ProgressAccumulator::New();
progress->SetMiniPipelineFilter(this);
progress->RegisterInternalFilter(m_IsoContourFilter, 0.5f);
progress->RegisterInternalFilter(m_ChamferFilter, 0.5f);
// set up the isocontour filter
m_IsoContourFilter->SetInput(this->GetInput());
m_IsoContourFilter->SetFarValue(maximumDistance + 1);
InputPixelType levelSetValue = (m_InsideValue + m_OutsideValue) / 2;
m_IsoContourFilter->SetLevelSetValue(levelSetValue);
// set up the chamfer filter
m_ChamferFilter->SetInput(m_IsoContourFilter->GetOutput());
m_ChamferFilter->SetMaximumDistance(maximumDistance);
// graft our output to the chamfer filter to force the proper regions
// to be generated
m_ChamferFilter->GraftOutput( this->GetOutput() );
// create the distance map
m_ChamferFilter->Update();
// graft the output of the chamfer filter back onto this filter's
// output. this is needed to get the appropriate regions passed
// back.
this->GraftOutput( m_ChamferFilter->GetOutput() );
// Recall that we set the isocontour value to halfway between the inside and
// oustide value. The above filters assume that regions "inside" objects are
// those with values *less* than the isocontour. This assumption is violated
// if the "inside" intensity value is greater than the "outside" value.
// (E.g. in the case that we're computing the distance from a mask where the
// background is zero and the objects are colored 255.)
// In this case, the distance will be calculated negative, so we need to
// flip the sign of the output image.
if (m_InsideValue > m_OutsideValue)
{
ImageRegionIterator< OutputImageType > ot( this->GetOutput(),
this->GetOutput()->GetRequestedRegion() );
ot.GoToBegin();
while( !ot.IsAtEnd() )
{
ot.Set(ot.Get() * -1);
++ot;
}
}
}
template<class TInputImage, class TOutputImage>
void
ApproximateSignedDistanceMapImageFilter<TInputImage, TOutputImage>
::PrintSelf(std::ostream &os, Indent indent) const
{
Superclass::PrintSelf(os, indent);
os << indent << "Inside intensity value: " << m_InsideValue << std::endl;
os << indent << "Outside intensity value: " << m_OutsideValue << std::endl;
os << indent << "IsoContourDistanceImageFilter (used internally): "
<< m_IsoContourFilter << std::endl;
os << indent << "FastChamferDistanceImageFilter (used internally): "
<< m_ChamferFilter << std::endl;
}
} // end of namespace itk
#endif
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