Histogram.h

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//     ____   ______ __
//    / __ \ / ____// /
//   / /_/ // /    / /
//  / ____// /___ / /___   PixInsight Class Library
// /_/     \____//_____/   PCL 2.7.0
// ----------------------------------------------------------------------------
// pcl/Histogram.h - Released 2024-06-18T15:48:54Z
// ----------------------------------------------------------------------------
// This file is part of the PixInsight Class Library (PCL).
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// ----------------------------------------------------------------------------
 
#ifndef __PCL_Histogram_h
#define __PCL_Histogram_h
 
 
#include <pcl/Defs.h>
#include <pcl/Diagnostics.h>
 
#include <pcl/ImageVariant.h>
#include <pcl/ParallelProcess.h>
#include <pcl/Vector.h>
 
namespace pcl
{
 
// ----------------------------------------------------------------------------
 
class PCL_CLASS Histogram : public ParallelProcess
{
public:
 
   using count_type = uint64;
 
   using histogram_type = UI64Vector;
 
   Histogram( int resolution = 0x10000L )
      : m_resolution( pcl::Max( 2, resolution ) )
   {
      PCL_PRECONDITION( resolution > 1 )
   }
 
   Histogram( const histogram_type& data )
   {
      SetHistogramData( data );
   }
 
   Histogram( const Histogram& ) = default;
 
   Histogram( Histogram&& ) = default;
 
   ~Histogram() override
   {
   }
 
   Histogram& operator =( const Histogram& ) = default;
 
   Histogram& operator =( Histogram&& ) = default;
 
   void Assign( const Histogram& x )
   {
      (void)operator =( x );
   }
 
   void Clear()
   {
      m_histogram.Clear();
      m_peakLevel = 0;
   }
 
   bool IsEmpty() const
   {
      return m_histogram.IsEmpty();
   }
 
   int Resolution() const
   {
      return m_resolution;
   }
 
   int LastLevel() const
   {
      return m_resolution-1;
   }
 
   void SetResolution( int resolution )
   {
      PCL_PRECONDITION( resolution > 1 )
      Clear();
      m_resolution = pcl::Max( 2, resolution );
   }
 
   void Allocate()
   {
      if ( m_histogram.IsEmpty() )
         m_histogram = histogram_type( m_resolution );
   }
 
   int PeakLevel() const
   {
      return m_histogram.IsEmpty() ? 0 : m_peakLevel;
   }
 
   double NormalizedPeakLevel() const
   {
      return NormalizedLevel( PeakLevel() );
   }
 
   int UpdatePeakLevel()
   {
      return m_peakLevel = m_histogram.IsEmpty() ? 0 :
                  int( pcl::MaxItem( m_histogram.Begin(), m_histogram.End() ) - m_histogram.Begin() );
   }
 
   int HistogramLevel( double x ) const
   {
      PCL_PRECONDITION( x >= 0 && x <= 1 )
      return RoundInt( pcl::Range( x, 0.0, 1.0 )*(m_resolution - 1) );
   }
 
   double NormalizedLevel( int i ) const
   {
      PCL_PRECONDITION( i >= 0 && i < m_resolution )
      return double( pcl::Range( i, 0, m_resolution-1 ) )/(m_resolution - 1);
   }
 
   void GetHistogramRange( int& i, int& j, double a, double b ) const
   {
      i = HistogramLevel( a );
      j = HistogramLevel( b );
      if ( j < i )
         pcl::Swap( i, j );
   }
 
   void GetNormalizedRange( double& a, double& b, int i, int j ) const
   {
      if ( j < i )
         pcl::Swap( i, j );
      a = NormalizedLevel( i );
      b = NormalizedLevel( j );
   }
 
   count_type Count() const
   {
      return m_histogram.Sum();
   }
 
   count_type Count( int i ) const
   {
      PCL_PRECONDITION( i >= 0 && i < m_histogram.Length() )
      if ( i < 0 || i >= m_histogram.Length() )
         return 0;
      return m_histogram[i];
   }
 
   count_type operator []( int i ) const
   {
      return Count( i );
   }
 
   count_type Count( int i, int j ) const
   {
      PCL_PRECONDITION( i >= 0 && i < m_histogram.Length() )
      PCL_PRECONDITION( j >= 0 && j < m_histogram.Length() )
      if ( m_histogram.IsEmpty() )
         return 0;
      i = pcl::Range( i, 0, m_histogram.Length()-1 );
      j = pcl::Range( j, 0, m_histogram.Length()-1 );
      if ( j < i )
         pcl::Swap( i, j );
      return pcl::Sum( m_histogram.At( i ), m_histogram.At( j+1 ) );
   }
 
   count_type PeakCount() const
   {
      return Count( m_peakLevel );
   }
 
   count_type PeakCount( int i, int j ) const
   {
      PCL_PRECONDITION( i >= 0 && i < m_histogram.Length() )
      PCL_PRECONDITION( j >= 0 && j < m_histogram.Length() )
      if ( m_histogram.IsEmpty() )
         return 0;
      i = pcl::Range( i, 0, m_histogram.Length()-1 );
      j = pcl::Range( j, 0, m_histogram.Length()-1 );
      if ( j < i )
         pcl::Swap( i, j );
      return *pcl::MaxItem( m_histogram.At( i ), m_histogram.At( j+1 ) );
   }
 
   int ClipLow( count_type n ) const
   {
      int i = 0;
      for ( count_type s = 0; i < m_histogram.Length()-1 && (s += m_histogram[i]) <= n; ++i ) {}
      return i;
   }
 
   double NormalizedClipLow( count_type n ) const
   {
      return NormalizedLevel( ClipLow( n ) );
   }
 
   int ClipHigh( count_type n ) const
   {
      int i = m_histogram.Length();
      for ( count_type s = 0; --i > 0 && (s += m_histogram[i]) <= n; ) {}
      return i;
   }
 
   double NormalizedClipHigh( count_type n ) const
   {
      return NormalizedLevel( ClipHigh( n ) );
   }
 
   const histogram_type& HistogramData() const
   {
      return m_histogram;
   }
 
   void SetHistogramData( const histogram_type& data )
   {
      if ( data.Length() < 2 )
         Clear();
      else
      {
         m_histogram = data;
         m_resolution = m_histogram.Length();
         UpdatePeakLevel();
      }
   }
 
   void GetData( count_type* where, int fromLevel = 0, int toLevel = -1 ) const
   {
      PCL_PRECONDITION( where != nullptr )
      PCL_PRECONDITION( fromLevel >= 0 )
      if ( where != nullptr )
         if ( !m_histogram.IsEmpty() )
         {
            fromLevel = pcl::Range( fromLevel, 0, m_histogram.Length()-1 );
            toLevel = (toLevel < 0) ? m_histogram.Length()-1 : pcl::Range( toLevel, 0, m_histogram.Length()-1 );
            if ( toLevel < fromLevel )
               pcl::Swap( fromLevel, toLevel );
            ::memcpy( where, m_histogram.At( fromLevel ), (1+toLevel-fromLevel)*sizeof( count_type ) );
         }
   }
 
   void Resample( Histogram& h ) const
   {
      if ( h.m_resolution == m_resolution )
         h = *this;
      else
      {
         if ( m_histogram.IsEmpty() )
            h.Clear();
         else
         {
            h.Allocate();
            h.m_histogram = 0;
            double k = double( h.m_histogram.Length() - 1 )/(m_histogram.Length() - 1);
            for ( int i = 0; i < m_histogram.Length(); ++i )
               h.m_histogram[pcl::RoundInt( i*k )] += m_histogram[i];
            h.m_peakLevel = int( pcl::MaxItem( h.m_histogram.Begin(), h.m_histogram.End() ) - h.m_histogram.Begin() );
         }
      }
   }
 
   double Entropy() const
   {
      double H = 0;
      count_type n = Count();
      if ( n > 0 )
         for ( int i = 0; i < m_histogram.Length(); ++i )
            if ( m_histogram[i] > 0 )
            {
               double f = double( m_histogram[i] )/n;
               H -= f*Log( f );
            }
      return H;
   }
 
   const Image&        operator <<( const Image& );
 
   const DImage&       operator <<( const DImage& );
 
   const UInt8Image&   operator <<( const UInt8Image& );
 
   const UInt16Image&  operator <<( const UInt16Image& );
 
   const UInt32Image&  operator <<( const UInt32Image& );
 
   const ImageVariant& operator <<( const ImageVariant& );
 
   const Rect& SelectedRectangle() const
   {
      return m_rect;
   }
 
   void SelectRectangle( const Rect& r )
   {
      m_rect = r;
   }
 
   void ClearRectangle()
   {
      m_rect = Rect( 0 );
   }
 
   int SelectedChannel() const
   {
      return m_channel;
   }
 
   void SelectChannel( int channel )
   {
      m_channel = pcl::Max( -1, channel );
   }
 
   void ClearSelectedChannel()
   {
      m_channel = -1;
   }
 
protected:
 
   histogram_type m_histogram;             // Discrete histogram levels
   int            m_resolution = 0x10000L; // Number of histogram levels
   int            m_peakLevel = 0;         // Maximum level (index of maximum count)
   Rect           m_rect = 0;              // ROI, Rect( 0 ) to use target image's selection
   int            m_channel = -1;          // < 0 to use target image's selection
 
   friend class View;
   friend class HistogramTransformation;
};
 
// ----------------------------------------------------------------------------
 
} // pcl
 
#endif  // __PCL_Histogram_h
 
// ----------------------------------------------------------------------------
// EOF pcl/Histogram.h - Released 2024-06-18T15:48:54Z