itkShapeUniqueLabelMapFilter.h

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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkShapeUniqueLabelMapFilter.h,v $
  Language:  C++
  Date:      $Date: 2009-08-11 14:24:44 $
  Version:   $Revision: 1.6 $

  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 __itkShapeUniqueLabelMapFilter_h
#define __itkShapeUniqueLabelMapFilter_h

#include "itkInPlaceLabelMapFilter.h"
#include "itkShapeLabelObjectAccessors.h"
#include <queue>

namespace itk {
template<class TImage>
class ITK_EXPORT ShapeUniqueLabelMapFilter : 
    public InPlaceLabelMapFilter<TImage>
{
public:
  typedef ShapeUniqueLabelMapFilter     Self;
  typedef InPlaceLabelMapFilter<TImage> Superclass;
  typedef SmartPointer<Self>            Pointer;
  typedef SmartPointer<const Self>      ConstPointer;

  typedef TImage                              ImageType;
  typedef typename ImageType::Pointer         ImagePointer;
  typedef typename ImageType::ConstPointer    ImageConstPointer;
  typedef typename ImageType::PixelType       PixelType;
  typedef typename ImageType::IndexType       IndexType;
  typedef typename ImageType::LabelObjectType LabelObjectType;
  typedef typename LabelObjectType::LineType  LineType;

  typedef typename LabelObjectType::AttributeType AttributeType;

  itkStaticConstMacro(ImageDimension, unsigned int,
                      TImage::ImageDimension);

  itkNewMacro(Self);

  itkTypeMacro(ShapeUniqueLabelMapFilter, 
               InPlaceLabelMapFilter);

#ifdef ITK_USE_CONCEPT_CHECKING

/*  itkConceptMacro(InputEqualityComparableCheck,
    (Concept::EqualityComparable<InputImagePixelType>));
  itkConceptMacro(IntConvertibleToInputCheck,
    (Concept::Convertible<int, InputImagePixelType>));
  itkConceptMacro(InputOStreamWritableCheck,
    (Concept::OStreamWritable<InputImagePixelType>));*/

#endif

  itkGetConstMacro( ReverseOrdering, bool );
  itkSetMacro( ReverseOrdering, bool );
  itkBooleanMacro( ReverseOrdering );

  itkGetConstMacro( Attribute, AttributeType );
  itkSetMacro( Attribute, AttributeType );
  void SetAttribute( const std::string & s )
    {
    this->SetAttribute( LabelObjectType::GetAttributeFromName( s ) );
    }


protected:
  ShapeUniqueLabelMapFilter();
  ~ShapeUniqueLabelMapFilter() {};

  void GenerateData();

  template <class TAttributeAccessor> 
  void TemplatedGenerateData( const TAttributeAccessor & accessor )
    {
    // Allocate the output
    this->AllocateOutputs();

    // the priority queue to store all the lines of all the objects sorted
    typedef typename std::priority_queue< LineOfLabelObject, std::vector<LineOfLabelObject>, LineOfLabelObjectComparator > PriorityQueueType;
    PriorityQueueType pq;

    ProgressReporter progress( this, 0, 1 );
    // TODO: really report the progress
    
    typedef typename ImageType::LabelObjectContainerType LabelObjectsType;

    const LabelObjectsType & labelObjects = this->GetLabelMap()->GetLabelObjectContainer();
    for( typename LabelObjectsType::const_iterator it2 = labelObjects.begin();
      it2 != labelObjects.end();
      it2++ )
      {
      LabelObjectType * lo = it2->second;
      
      // may reduce the number of lines to proceed
      lo->Optimize();
      
      typename LabelObjectType::LineContainerType::const_iterator lit;
      typename LabelObjectType::LineContainerType & lineContainer = lo->GetLineContainer();
    
      for( lit = lineContainer.begin(); lit != lineContainer.end(); lit++ )
        {
        pq.push( LineOfLabelObject( *lit, lo ) );
        }
      
      // clear the lines to readd them later
      lineContainer.clear();
      
      // go to the next label
      // progress.CompletedPixel();
      }
      
    if( pq.empty() )
      {
      // nothing to do
      return;
      }
      
    typedef typename std::deque<LineOfLabelObject> LinesType;
    LinesType lines;

    lines.push_back( pq.top() );
    LineOfLabelObject prev = lines.back();
    IndexType prevIdx = prev.line.GetIndex();
    pq.pop();
    
    while( !pq.empty() )
      {
      LineOfLabelObject l = pq.top();
      IndexType idx = l.line.GetIndex();
      pq.pop();
      
      bool newMainLine = false;
      // don't check dim 0!
      for( int i=1; i<ImageDimension; i++ )
        {
        if( idx[i] != prevIdx[i] )
          {
          newMainLine = true;
          }
        }
      
      if( newMainLine )
        {
        // just push the line
        lines.push_back( l );
        }
      else
        {
        unsigned long prevLength = prev.line.GetLength();
        unsigned long length = l.line.GetLength();
        
        if( prevIdx[0] + (long)prevLength >= idx[0] )
          {
          // the lines are overlapping. We need to choose which line to keep.
          // the label, the only "attribute" to be guarenteed to be unique, is used to choose
          // which line to keep. This is necessary to avoid the case where a part of a label is over
          // a second label, and below in another part of the image.
          bool keepCurrent;
          typename TAttributeAccessor::AttributeValueType prevAttr = accessor( prev.labelObject );
          typename TAttributeAccessor::AttributeValueType attr = accessor( l.labelObject );
          // this may be changed to a single boolean expression, but may become quite difficult to read
          if( attr == prevAttr  )
            {
            if( l.labelObject->GetLabel() > prev.labelObject->GetLabel() )
              {
              keepCurrent = !m_ReverseOrdering;
              }
            else
              {
              keepCurrent = m_ReverseOrdering;
              }
            }
          else
            {
            if( attr > prevAttr )
              {
              keepCurrent = !m_ReverseOrdering;
              }
            else
              {
              keepCurrent = m_ReverseOrdering;
              }
            }
          
          if( keepCurrent )
            {
            // keep the current one. We must truncate the previous one to remove the
            // overlap, and take care of the end of the previous line if it extends
            // after the current one.
            if( prevIdx[0] + prevLength > idx[0] + length )
              {
              // the previous line is longer than the current one. Lets take its tail and
              // add it to the priority queue
              IndexType newIdx = idx;
              newIdx[0] = idx[0] + length;
              unsigned long newLength = prevIdx[0] + prevLength - newIdx[0];
              pq.push( LineOfLabelObject( LineType( newIdx, newLength ), prev.labelObject ) );
              }
            // truncate the previous line to let some place for the current one
            prevLength = idx[0] - prevIdx[0];
            if( prevLength != 0 )
              {
              lines.back().line.SetLength( idx[0] - prevIdx[0] );
              }
            else
              {
              // length is 0 - no need to keep that line
              lines.pop_back();
              }
            // and push the current one
            lines.push_back( l );
            }
          else
            {
            // keep the previous one. If the previous line fully overlap the current one,
            // the current one is fully discarded.
            if( prevIdx[0] + prevLength > idx[0] + length )
              {
              // discarding the current line - just do nothing
              }
            else
              {
              IndexType newIdx = idx;
              newIdx[0] = prevIdx[0] + prevLength;
              unsigned long newLength = idx[0] + length - newIdx[0];
              l.line.SetIndex( newIdx );
              l.line.SetLength( newLength );
              lines.push_back( l );
              }
            
            }
          }
        else
          {
          // no overlap - things are just fine already
          lines.push_back( l );
          }
        }
      
      // store the current line as the previous one, and go to the next one.
      prev = lines.back();
      prevIdx = prev.line.GetIndex();
      }
    
    // put the lines in their object
    for( unsigned int i=0; i<lines.size(); i++ )
      {
      LineOfLabelObject & l = lines[i];
      l.labelObject->AddLine( l.line );
      }

    // remove objects without lines
    typename LabelObjectsType::const_iterator it = labelObjects.begin();
    while( it != labelObjects.end() )
      {
      typename LabelObjectType::LabelType label = it->first;
      LabelObjectType * labelObject = it->second;

      if( labelObject->Empty() )
        {
        // must increment the iterator before removing the object to avoid invalidating the iterator
        it++;
        this->GetLabelMap()->RemoveLabel( label );
        }
      else
        {
        it++;
        }

      }
    }

  void PrintSelf(std::ostream& os, Indent indent) const;

  AttributeType m_Attribute;

private:
  ShapeUniqueLabelMapFilter(const Self&); //purposely not implemented
  void operator=(const Self&); //purposely not implemented

  bool          m_ReverseOrdering;
  struct LineOfLabelObject
    {
    typedef typename LabelObjectType::LineType LineType;
    LineOfLabelObject( const LineType _line, LabelObjectType * _lo )
      {
      this->line = _line;
      this->labelObject = _lo;
      }
    LineType          line;
    LabelObjectType * labelObject;
    };

  class LineOfLabelObjectComparator
    {
    public:
    bool operator()( const LineOfLabelObject & lla, const LineOfLabelObject & llb )
      {
      for( int i=ImageDimension-1; i>=0; i-- )
        {
        if( lla.line.GetIndex()[i] > llb.line.GetIndex()[i] )
          {
          return true;
          }
        else if( lla.line.GetIndex()[i] < llb.line.GetIndex()[i] )
          {
          return false;
          }
        }
      return false;
      }
    };

}; // end of class

} // end namespace itk
  
#ifndef ITK_MANUAL_INSTANTIATION
#include "itkShapeUniqueLabelMapFilter.txx"
#endif

#endif