itkRankHistogram.h

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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkRankHistogram.h,v $
  Language:  C++
  Date:      $Date: 2008-10-04 12:43:20 $
  Version:   $Revision: 1.4 $

  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.

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

// histogram from the moving histogram operations
#ifndef __itkRankHistogram_h
#define __itkRankHistogram_h
#include "itkNumericTraits.h"

namespace itk {

// a simple histogram class hierarchy. One subclass will be maps, the
// other vectors.
// This version is intended for keeping track of arbitary ranks. It is
// based on the code from consolidatedMorphology.
//
// Support for different TCompare hasn't been tested, and shouldn't be
// necessary for the rank filters.
//
#include <sstream>

template <class TInputPixel>
class RankHistogram
{
public:
  RankHistogram() 
    {
    m_Rank = 0.5;
    }
  virtual ~RankHistogram(){}

  virtual RankHistogram * Clone() const 
    {
    return 0;
    }
   
  virtual void AddPixel(const TInputPixel &itkNotUsed(p)){}

  virtual void RemovePixel(const TInputPixel &itkNotUsed(p)){}
 
  void AddBoundary(){}

  void RemoveBoundary(){}
 
  virtual TInputPixel GetValue( const TInputPixel & ){return 0;}

  void SetRank(float rank)
    {
    m_Rank = rank;
    }

protected:
  float m_Rank;
};

template <class TInputPixel, class TCompare>
class RankHistogramMap : public RankHistogram<TInputPixel>
{
public:

  typedef RankHistogram<TInputPixel>       Superclass;

public:
  RankHistogramMap() 
    {
    m_Below = m_Entries = 0;
    // can't set m_RankIt until something has been put in the histogram
    m_Initialized = false;
    if( m_Compare( NumericTraits< TInputPixel >::max(), 
                   NumericTraits< TInputPixel >::NonpositiveMin() ) )
      {
      m_InitVal = NumericTraits< TInputPixel >::NonpositiveMin();
      }
    else
      {
      m_InitVal = NumericTraits< TInputPixel >::max();
      }
    m_RankValue = m_InitVal;
    m_RankIt = m_Map.begin();  // equivalent to setting to the intial value
    }
  ~RankHistogramMap()
    {
    }

  void AddPixel(const TInputPixel &p)
    {
    m_Map[ p ]++;
    ++m_Entries;
    if (!m_Initialized)
      {
      m_Initialized = true;
      m_RankIt = m_Map.begin();
      m_RankValue = p;
      }
    if (m_Compare(p, m_RankValue) || p == m_RankValue)
      {
      ++m_Below;
      }

    }

  void RemovePixel(const TInputPixel &p)
    {
    m_Map[ p ]--; 
    if (m_Compare(p, m_RankValue) || p == m_RankValue)
      {
      --m_Below;
      }
    --m_Entries;
    }
 
  void Initialize()
    {
    m_RankIt = m_Map.begin();
    }

  TInputPixel GetValue( const TInputPixel & )
    {
    unsigned long target = (int)(this->m_Rank * (m_Entries-1)) + 1;
    unsigned long total = m_Below;
    unsigned long ThisBin;
    bool eraseFlag = false;

    // an assert is better than a log message in that case
    assert(m_Initialized);

    if (total < target)
      {
      typename MapType::iterator searchIt = m_RankIt;
      typename MapType::iterator eraseIt;
      
      while (searchIt != m_Map.end())
        {
        // cleaning up the map - probably a better way of organising
        // the loop. Currently makes sure that the search iterator is
        // incremented before deleting
        ++searchIt;
        ThisBin = searchIt->second;
        total += ThisBin;
        if (eraseFlag)
          {
          m_Map.erase(eraseIt);
          eraseFlag = false;
          }
        if (ThisBin <= 0)
          {
          eraseFlag = true;
          eraseIt = searchIt;
          }
        if (total >= target)
          break;
        }
      m_RankValue = searchIt->first;
      m_RankIt = searchIt;
      }
    else
      {
      typename MapType::iterator searchIt = m_RankIt;
      typename MapType::iterator eraseIt;

      while(searchIt != m_Map.begin())
        {
        ThisBin = searchIt->second;
        unsigned int tbelow = total - ThisBin;
        if (tbelow < target) // we've overshot
          break;
        if (eraseFlag)
          {
          m_Map.erase(eraseIt);
          eraseFlag = false;
          }
        if (ThisBin <= 0)
          {
          eraseIt = searchIt;
          eraseFlag = true;
          }
        total = tbelow;
//         std::cout << searchIt->first << std::endl;

        --searchIt;
        }
      m_RankValue = searchIt->first;
      m_RankIt = searchIt;
      }

    m_Below = total;

    return(m_RankValue);

    }

  Superclass * Clone() const
    {
    RankHistogramMap *result = new RankHistogramMap();
    result->m_Map = this->m_Map;
    result->m_Rank = this->m_Rank;
    result->m_Below = this->m_Below;
    result->m_Entries = this->m_Entries;
    result->m_InitVal = this->m_InitVal;
    result->m_RankValue = this->m_RankValue;
    result->m_Initialized = this->m_Initialized;
    if (result->m_Initialized)
      result->m_RankIt = result->m_Map.find(this->m_RankValue);
    return(result);
    }

private:
  typedef typename std::map< TInputPixel, unsigned long, TCompare > MapType;
  
  MapType       m_Map;
  unsigned long m_Below;
  unsigned long m_Entries;
  TInputPixel   m_RankValue;
  TInputPixel   m_InitVal;
  TCompare      m_Compare;
  bool          m_Initialized;
  // This iterator will point at the desired rank value
  typename MapType::iterator m_RankIt;
};

template <class TInputPixel, class TCompare>
class RankHistogramVec : public RankHistogram<TInputPixel>
{
public:
  typedef RankHistogram<TInputPixel>       Superclass;

public:
  RankHistogramVec() 
    {
    m_Size = static_cast<unsigned int>( NumericTraits< TInputPixel >::max() - 
                                        NumericTraits< TInputPixel >::NonpositiveMin() + 1 );
    m_Vec.resize(m_Size, 0 );
    if( m_Compare( NumericTraits< TInputPixel >::max(), 
                   NumericTraits< TInputPixel >::NonpositiveMin() ) )
      {
      m_InitVal = NumericTraits< TInputPixel >::NonpositiveMin();
      }
    else
      {
      m_InitVal = NumericTraits< TInputPixel >::max();
      }
    m_Entries = m_Below = 0;
    m_RankValue = m_InitVal  - NumericTraits< TInputPixel >::NonpositiveMin();
    }

  RankHistogramVec(bool NoInit) 
    {
    m_Size = static_cast<unsigned int>( NumericTraits< TInputPixel >::max() - 
                                        NumericTraits< TInputPixel >::NonpositiveMin() + 1 );
    if (!NoInit) m_Vec.resize(m_Size, 0 );
    if( m_Compare( NumericTraits< TInputPixel >::max(), 
                   NumericTraits< TInputPixel >::NonpositiveMin() ) )
      {
      m_InitVal = NumericTraits< TInputPixel >::NonpositiveMin();
      }
    else
      {
      m_InitVal = NumericTraits< TInputPixel >::max();
      }
    m_Entries = m_Below = 0;
    m_RankValue = m_InitVal  - NumericTraits< TInputPixel >::NonpositiveMin();
    }


  ~RankHistogramVec()
    {
    }

  TInputPixel GetValue( const TInputPixel & )
    {
    unsigned long target = (int)(this->m_Rank * (m_Entries-1)) + 1;
    unsigned long total = m_Below;
    long unsigned int pos = (long unsigned int)(m_RankValue - NumericTraits< TInputPixel >::NonpositiveMin()); 

    if (total < target)
      {
      while (pos < m_Size)
        {
        ++pos;
        total += m_Vec[pos];
        if (total >= target)
          break;
        }
      }
    else
      {
      while(pos > 0)
        {
        unsigned int tbelow = total - m_Vec[pos];
        if (tbelow < target) // we've overshot
          break;
        total = tbelow;
        --pos;
        }
      }

    m_RankValue = (TInputPixel)(pos + NumericTraits< TInputPixel >::NonpositiveMin());
    m_Below = total;
    return(m_RankValue);
    }

  void AddPixel(const TInputPixel &p)
    {
    long unsigned int idx = (long unsigned int)(p - NumericTraits< TInputPixel >::NonpositiveMin());
    m_Vec[ idx  ]++; 
    if (m_Compare(p, m_RankValue) || p == m_RankValue)
      {
      ++m_Below;
      }
    ++m_Entries;
    }

  void RemovePixel(const TInputPixel &p)
    {
    assert(p - NumericTraits< TInputPixel >::NonpositiveMin() >= 0);
    assert(p - NumericTraits< TInputPixel >::NonpositiveMin() < (int)m_Vec.size());
    assert(m_Entries >= 1);
    m_Vec[ (long unsigned int)(p - NumericTraits< TInputPixel >::NonpositiveMin())  ]--; 
    --m_Entries;

    if (m_Compare(p, m_RankValue) || p == m_RankValue)
      {
      --m_Below;
      }
    }
 
  Superclass * Clone() const
    {
    RankHistogramVec *result = new RankHistogramVec(true);
    result->m_Vec = this->m_Vec;
    result->m_Size = this->m_Size;
    //result->m_CurrentValue = this->m_CurrentValue;
    result->m_InitVal = this->m_InitVal;
    result->m_Entries = this->m_Entries;
    result->m_Below = this->m_Below;
    result->m_Rank = this->m_Rank;
    result->m_RankValue = this->m_RankValue;
    return(result);
    }

private:
  typedef typename std::vector<unsigned long> VecType;
  
  VecType      m_Vec;
  unsigned int m_Size;
  TCompare     m_Compare;
  //unsigned int m_CurrentValue;
  //TInputPixel m_CurrentValue;
  TInputPixel  m_RankValue;
  TInputPixel  m_InitVal;
  int          m_Below;
  int          m_Entries;
};

} // end namespace itk
#endif

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