lib/fpa/Image/RegionGrowWithMultipleThresholds.hxx

   1 #ifndef __FPA__IMAGE__REGIONGROWWITHMULTIPLETHRESHOLDS__HXX__
   2 #define __FPA__IMAGE__REGIONGROWWITHMULTIPLETHRESHOLDS__HXX__
   3
   4 #include <limits>
   5 #include <itkBinaryThresholdImageFilter.h>
   6 #include <itkConstNeighborhoodIterator.h>
   7
   8 // -------------------------------------------------------------------------
   9 template< class I >
  10 void fpa::Image::RegionGrowWithMultipleThresholds< I >::
  11 AddThreshold( const TPixel& v )
  12 {
  13   this->m_Thresholds.insert( v );
  14   this->Modified( );
  15 }
  16
  17 // -------------------------------------------------------------------------
  18 template< class I >
  19 void fpa::Image::RegionGrowWithMultipleThresholds< I >::
  20 AddThresholds( const TPixel& t0, const TPixel& t1, const unsigned int& s )
  21 {
  22   for( TPixel t = t0; t <= t1; t += TPixel( s ) )
  23     this->AddThreshold( t );
  24 }
  25
  26 // -------------------------------------------------------------------------
  27 template< class I >
  28 fpa::Image::RegionGrowWithMultipleThresholds< I >::
  29 RegionGrowWithMultipleThresholds( )
  30   : Superclass( ),
  31     m_InsideValue( TPixel( 1 ) ),
  32     m_OutsideValue( TPixel( 0 ) ),
  33     m_DifferenceThreshold( double( 3 ) ),
  34     m_TotalCount( 0 ),
  35     m_LastDiff( double( 0 ) ),
  36     m_StopForced( false ),
  37     m_StopThreshold( TPixel( 0 ) )
  38 {
  39 }
  40
  41 // -------------------------------------------------------------------------
  42 template< class I >
  43 fpa::Image::RegionGrowWithMultipleThresholds< I >::
  44 ~RegionGrowWithMultipleThresholds( )
  45 {
  46 }
  47
  48 // -------------------------------------------------------------------------
  49 template< class I >
  50 void fpa::Image::RegionGrowWithMultipleThresholds< I >::
  51 _BeforeMainLoop( )
  52 {
  53   const I* img = this->GetInput( );
  54
  55   // Clear all states
  56   this->ClearMembershipFunctions( );
  57   this->m_Histogram.clear( );
  58   this->m_TotalCount = img->GetLargestPossibleRegion( ).GetNumberOfPixels( );
  59   this->m_LastDiff = double( -1 );
  60   this->m_StopForced = false;
  61
  62   // Initialize thresholding functors
  63   typename TThresholds::const_iterator tIt = this->m_Thresholds.begin( );
  64   TPixel min_thr = std::numeric_limits< TPixel >::min( );
  65   for( ; tIt != this->m_Thresholds.end( ); ++tIt )
  66   {
  67     typename TFunction::Pointer function = TFunction::New( );
  68     function->SetInputImage( img );
  69     function->SetLowerThreshold( min_thr );
  70     function->SetUpperThreshold( *tIt );
  71     this->AddMembershipFunction( function );
  72
  73   } // rof
  74
  75   // Correct seeds
  76   typename I::SizeType radius;
  77   radius.Fill( 3 );
  78   itk::ConstNeighborhoodIterator< I > it(
  79     radius, img, img->GetRequestedRegion( )
  80     );
  81   for( unsigned int s = 0; s < this->m_Seeds.size( ); ++s )
  82   {
  83     _TNode seed = this->m_Seeds[ s ];
  84     it.SetLocation( seed.Vertex );
  85
  86     typename I::SizeType size = it.GetSize( );
  87     unsigned int nN = 1;
  88     for( unsigned int d = 0; d < I::ImageDimension; ++d )
  89       nN *= size[ d ];
  90     TPixel min_value = img->GetPixel( seed.Vertex );
  91     for( unsigned int i = 0; i < nN; ++i )
  92     {
  93       if( it.GetPixel( i ) < min_value )
  94       {
  95         seed.Vertex = it.GetIndex( i );
  96         min_value = it.GetPixel( i );
  97
  98       } // fi
  99
 100     } // rof
 101     this->m_Seeds[ s ] = seed;
 102
 103   } // rof
 104
 105   // Continue all initializations
 106   this->Superclass::_BeforeMainLoop( );
 107 }
 108
 109 // -------------------------------------------------------------------------
 110 template< class I >
 111 void fpa::Image::RegionGrowWithMultipleThresholds< I >::
 112 _AfterMainLoop( )
 113 {
 114   typedef itk::BinaryThresholdImageFilter< I, I > _TBinFilter;
 115
 116   // Binarize, inplace, the grown region
 117   if( this->m_Histogram.size( ) > 1 )
 118   {
 119     typename _TBinFilter::Pointer bin = _TBinFilter::New( );
 120     bin->SetInput( this->GetOutput( ) );
 121     bin->SetInsideValue( this->m_InsideValue );
 122     bin->SetOutsideValue( this->m_OutsideValue );
 123     bin->InPlaceOn( );
 124     if( this->m_StopForced )
 125       bin->SetUpperThreshold( this->m_StopThreshold );
 126     else
 127       bin->SetUpperThreshold( this->m_Histogram.rbegin( )->first );
 128     bin->GraftOutput( this->GetOutput( ) );
 129     bin->Update( );
 130     this->GraftOutput( bin->GetOutput( ) );
 131
 132   } // fi
 133
 134   this->Superclass::_AfterMainLoop( );
 135 }
 136
 137 // -------------------------------------------------------------------------
 138 template< class I >
 139 void fpa::Image::RegionGrowWithMultipleThresholds< I >::
 140 _AfterLoop( )
 141 {
 142   if( this->m_ActualFunction != this->m_Functions.end( ) )
 143   {
 144     TFunction* f =
 145       dynamic_cast< TFunction* >( this->m_ActualFunction->GetPointer( ) );
 146     this->m_Histogram[ f->GetUpperThreshold( ) ] = this->m_Marks.size( );
 147
 148     /* TODO: code to print the signal for demo purposes
 149        std::cout
 150        << f->GetUpperThreshold( ) << " "
 151        << this->m_Marks.size( )
 152        << std::endl;
 153     */
 154
 155     // Get the two last complete count, if any, and compute last
 156     // finite difference
 157     if( this->m_Histogram.size( ) > 1 )
 158     {
 159       typename THistogram::const_reverse_iterator hIt =
 160         this->m_Histogram.rbegin( );
 161       typename THistogram::const_reverse_iterator gIt = hIt;
 162       gIt++;
 163
 164       this->m_LastDiff  = double( hIt->second ) - double( gIt->second );
 165       this->m_LastDiff /= double( hIt->first )  - double( gIt->first );
 166       this->m_LastDiff *= m_DifferenceThreshold;
 167     }
 168     else
 169       this->m_LastDiff = double( -1 );
 170
 171   } // fi
 172   this->Superclass::_AfterLoop( );
 173 }
 174
 175 // -------------------------------------------------------------------------
 176 template< class I >
 177 bool fpa::Image::RegionGrowWithMultipleThresholds< I >::
 178 _UpdateResult( _TNode& n )
 179 {
 180   // Here, the output is changed to the threshold used to compute the
 181   // growing condition of the actual vertex n
 182   bool ret = this->Superclass::_UpdateResult( n );
 183   if( this->m_ActualFunction != this->m_Functions.end( ) )
 184   {
 185     TFunction* f =
 186       dynamic_cast< TFunction* >( this->m_ActualFunction->GetPointer( ) );
 187     if( f != NULL )
 188       this->GetOutput( )->SetPixel( n.Vertex, f->GetUpperThreshold( ) );
 189
 190   } // fi
 191   return( ret );
 192 }
 193
 194 // -------------------------------------------------------------------------
 195 template< class I >
 196 void fpa::Image::RegionGrowWithMultipleThresholds< I >::
 197 _Mark( const _TNode& n )
 198 {
 199   this->Superclass::_Mark( n );
 200
 201   // Check if the histogram's support is enough
 202   if( this->m_Histogram.size( ) < 2 )
 203     return;
 204   typename THistogram::const_reverse_iterator hIt =
 205     this->m_Histogram.rbegin( );
 206
 207   // Get the actual function
 208   TFunction* f =
 209     dynamic_cast< TFunction* >( this->m_ActualFunction->GetPointer( ) );
 210   if( f == NULL )
 211     return;
 212
 213   // Previous pixel count
 214   unsigned long prev_aCount = hIt->second;
 215   double prev_p = double( prev_aCount ) / double( this->m_TotalCount );
 216
 217   // Actual pixel count
 218   unsigned long aCount = this->m_Marks.size( );
 219   double p = double( aCount ) / double( this->m_TotalCount );
 220
 221   // Loop over, at least, 0.1% of the total number of pixels before
 222   // performing stop analysis
 223   if( double( 1e-3 ) < p && double( 1e-3 ) < prev_p )
 224   {
 225     // Does the difference is worthy to be analyzed?
 226     if( aCount > hIt->second )
 227     {
 228       // Compute finite difference and compare it to the previous one
 229       double diff = double( aCount ) - double( hIt->second );
 230       diff /= double( f->GetUpperThreshold( ) ) - double( hIt->first );
 231       if( diff > this->m_LastDiff )
 232       {
 233         this->m_StopForced = true;
 234         this->m_StopThreshold = hIt->first;
 235
 236       } // fi
 237
 238     } // fi
 239
 240   } // fi
 241 }
 242
 243 // -------------------------------------------------------------------------
 244 template< class I >
 245 bool fpa::Image::RegionGrowWithMultipleThresholds< I >::
 246 _CheckStopCondition( )
 247 {
 248   return( this->m_StopForced );
 249 }
 250
 251 #endif // __FPA__IMAGE__REGIONGROWWITHMULTIPLETHRESHOLDS__HXX__
 252
 253 // eof - $RCSfile$