ITK/Code/BasicFilters/itkConnectedComponentAlgorithm.h

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/*=========================================================================

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkConnectedComponentAlgorithm.h,v $
  Language:  C++
  Date:      $Date: 2008-10-13 18:54:27 $
  Version:   $Revision: 1.3 $

  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 __itkConnectedComponentAlgorithm_h
#define __itkConnectedComponentAlgorithm_h

#include "itkImage.h"
#include "itkConstShapedNeighborhoodIterator.h"
#include "itkShapedNeighborhoodIterator.h"

namespace itk
{
template< class TIterator >
TIterator*
setConnectivity( TIterator* it, bool fullyConnected=false )
{
  typename TIterator::OffsetType offset;
  it->ClearActiveList();
  if( !fullyConnected) 
    {
    // only activate the neighbors that are face connected
    // to the current pixel. do not include the center pixel
    offset.Fill( 0 );
    for( unsigned int d=0; d < TIterator::Dimension; ++d )
      {
      offset[d] = -1;
      it->ActivateOffset( offset );
      offset[d] = 1;
      it->ActivateOffset( offset );
      offset[d] = 0;
      }
    }
  else
    {
    // activate all neighbors that are face+edge+vertex
    // connected to the current pixel. do not include the center pixel
    unsigned int centerIndex = it->GetCenterNeighborhoodIndex();
    for( unsigned int d=0; d < centerIndex*2 + 1; d++ )
      {
      offset = it->GetOffset( d );
      it->ActivateOffset( offset );
      }
    offset.Fill(0);
    it->DeactivateOffset( offset );
    }
  return it;
}

template< class TIterator >
TIterator*
setConnectivityPrevious( TIterator* it, bool fullyConnected=false )
{
  // activate the "previous" neighbours
  typename TIterator::OffsetType offset;
  it->ClearActiveList();
  if( !fullyConnected) 
    {
    // only activate the neighbors that are face connected
    // to the current pixel. do not include the center pixel
    offset.Fill( 0 );
    for( unsigned int d=0; d < TIterator::Dimension; ++d )
      {
      offset[d] = -1;
      it->ActivateOffset( offset );
      offset[d] = 0;
      }
    }
  else
    {
    // activate all neighbors that are face+edge+vertex
    // connected to the current pixel. do not include the center pixel
    unsigned int centerIndex = it->GetCenterNeighborhoodIndex();
    for( unsigned int d=0; d < centerIndex; d++ )
      {
      offset = it->GetOffset( d );
      it->ActivateOffset( offset );
      }
    offset.Fill(0);
    it->DeactivateOffset( offset );
    }
  return it;
}

template< class TIterator >
TIterator*
setConnectivityLater( TIterator* it, bool fullyConnected=false )
{
  // activate the "later" neighbours
  typename TIterator::OffsetType offset;
  it->ClearActiveList();
  if( !fullyConnected) 
    {
    // only activate the neighbors that are face connected
    // to the current pixel. do not include the center pixel
    offset.Fill( 0 );
    for( unsigned int d=0; d < TIterator::Dimension; ++d )
      {
      offset[d] = 1;
      it->ActivateOffset( offset );
      offset[d] = 0;
      }
    }
  else
    {
    // activate all neighbors that are face+edge+vertex
    // connected to the current pixel. do not include the center pixel
    unsigned int centerIndex = it->GetCenterNeighborhoodIndex();
    for( unsigned int d=centerIndex+1; d < 2*centerIndex+1; d++ )
      {
      offset = it->GetOffset( d );
      it->ActivateOffset( offset );
      }
    offset.Fill(0);
    it->DeactivateOffset( offset );
    }
  return it;
}

}


#endif