1 // =========================================================================
2 // @author Leonardo Florez Valencia
3 // @email florez-l@javeriana.edu.co
4 // =========================================================================
6 #ifndef __fpa__Image__SkeletonFilter__hxx__
7 #define __fpa__Image__SkeletonFilter__hxx__
10 #include <itkImageRegionIteratorWithIndex.h>
11 #include <itkMinimumMaximumImageCalculator.h>
12 #include <fpa/Image/Functors/Dijkstra/Invert.h>
14 // -------------------------------------------------------------------------
15 template< class _TInputImage, class _TDistanceMap >
16 fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::_TDijkstra::
20 // Prepare weight function
21 typedef fpa::Image::Functors::Dijkstra::Invert< TOutputImage, TScalar > _TWeight;
22 typename _TWeight::Pointer weight = _TWeight::New( );
23 weight->SetAlpha( 1 );
25 this->SetWeightFunction( weight );
28 // -------------------------------------------------------------------------
29 template< class _TInputImage, class _TDistanceMap >
30 fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::_TDijkstra::
35 // -------------------------------------------------------------------------
36 template< class _TInputImage, class _TDistanceMap >
37 void fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::_TDijkstra::
38 _BeforeGenerateData( )
40 this->Superclass::_BeforeGenerateData( );
41 this->m_SkeletonQueue.clear( );
44 // -------------------------------------------------------------------------
45 template< class _TInputImage, class _TDistanceMap >
46 void fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::_TDijkstra::
47 _UpdateOutputValue( const TNode& n )
49 typedef typename _TSkeletonQueue::value_type _TSkeletonQueueValue;
51 this->Superclass::_UpdateOutputValue( n );
52 double d = double( this->GetInput( )->GetPixel( n.Vertex ) );
53 if( d >= double( 0 ) )
55 // Update skeleton candidates
57 double v = double( n.Value ) / ( d * d );
58 this->m_SkeletonQueue.insert( _TSkeletonQueueValue( v, n.Vertex ) );
63 // -------------------------------------------------------------------------
64 template< class _TInputImage, class _TDistanceMap >
66 fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::
69 itk::ModifiedTimeType t = this->Superclass::GetMTime( );
70 itk::ModifiedTimeType q = this->m_DistanceMap->GetMTime( );
71 return( ( q < t )? q: t );
74 // -------------------------------------------------------------------------
75 template< class _TInputImage, class _TDistanceMap >
76 void fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::
77 SetInput( TInputImage* input )
79 this->Superclass::SetNthInput( 0, input );
82 // -------------------------------------------------------------------------
83 template< class _TInputImage, class _TDistanceMap >
84 typename fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::
85 TInputImage* fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::
88 return( dynamic_cast< TInputImage* >( this->Superclass::GetInput( 0 ) ) );
91 // -------------------------------------------------------------------------
92 template< class _TInputImage, class _TDistanceMap >
93 const typename fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::
94 TInputImage* fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::
98 dynamic_cast< const TInputImage* >( this->Superclass::GetInput( 0 ) )
102 // -------------------------------------------------------------------------
103 template< class _TInputImage, class _TDistanceMap >
104 typename fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::
105 TSkeleton* fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::
108 return( dynamic_cast< TSkeleton* >( this->Superclass::GetOutput( 0 ) ) );
111 // -------------------------------------------------------------------------
112 template< class _TInputImage, class _TDistanceMap >
113 const typename fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::
114 TSkeleton* fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::
118 dynamic_cast< const TSkeleton* >( this->Superclass::GetOutput( 0 ) )
122 // -------------------------------------------------------------------------
123 template< class _TInputImage, class _TDistanceMap >
124 fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::
127 m_SeedFromMaximumDistance( false )
129 this->SetNumberOfRequiredInputs( 1 );
130 this->SetNumberOfRequiredOutputs( 1 );
131 this->SetNthOutput( 0, TSkeleton::New( ) );
133 this->m_DistanceMap = TDistanceMap::New( );
136 // -------------------------------------------------------------------------
137 template< class _TInputImage, class _TDistanceMap >
138 fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::
143 // -------------------------------------------------------------------------
144 template< class _TInputImage, class _TDistanceMap >
145 void fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::
148 // Update distance map
149 this->m_DistanceMap->SetInput( this->GetInput( ) );
150 this->m_DistanceMap->Update( );
153 if( this->m_SeedFromMaximumDistance )
155 typedef itk::MinimumMaximumImageCalculator< TOutputImage > _TMinMax;
156 typename _TMinMax::Pointer minmax = _TMinMax::New( );
157 minmax->SetImage( this->m_DistanceMap->GetOutput( ) );
159 this->m_Seed = minmax->GetIndexOfMaximum( );
164 typename _TDijkstra::Pointer dijkstra = _TDijkstra::New( );
165 dijkstra->SetInput( this->m_DistanceMap->GetOutput( ) );
166 dijkstra->AddSeed( this->m_Seed );
169 // Compute end-points
170 std::vector< TIndex > end_points;
173 this->m_DistanceMap->GetOutput( ),
174 dijkstra->GetMinimumSpanningTree( ),
175 dijkstra->GetSkeletonQueue( )
179 // -------------------------------------------------------------------------
180 template< class _TInputImage, class _TDistanceMap >
181 template< class _TMarksPointer >
182 void fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::
184 _TMarksPointer& marks, const TOutputImage* dmap, const TIndex& center
187 typedef typename _TMarksPointer::ObjectType _TMarks;
188 typedef itk::ImageRegionIteratorWithIndex< _TMarks > _TMarksIt;
190 static const double _eps = std::sqrt( double( Self::Dimension + 1 ) );
191 typename _TMarks::SpacingType spac = dmap->GetSpacing( );
192 typename _TMarks::RegionType region = dmap->GetRequestedRegion( );
194 typename _TMarks::PointType cnt;
195 dmap->TransformIndexToPhysicalPoint( center, cnt );
196 double r = double( dmap->GetPixel( center ) ) * _eps;
199 for( unsigned int d = 0; d < Self::Dimension; ++d )
201 long off = long( std::ceil( r / double( spac[ d ] ) ) );
204 i0[ d ] = center[ d ] - off;
205 i1[ d ] = center[ d ] + off;
207 if( i0[ d ] < region.GetIndex( )[ d ] )
208 i0[ d ] = region.GetIndex( )[ d ];
210 if( i1[ d ] >= region.GetIndex( )[ d ] + region.GetSize( )[ d ] )
211 i1[ d ] = region.GetIndex( )[ d ] + region.GetSize( )[ d ] - 1;
215 typename _TMarks::SizeType size;
216 for( unsigned int d = 0; d < Self::Dimension; ++d )
217 size[ d ] = i1[ d ] - i0[ d ] + 1;
219 typename _TMarks::RegionType neighRegion;
220 neighRegion.SetIndex( i0 );
221 neighRegion.SetSize( size );
223 _TMarksIt mIt( marks, neighRegion );
224 for( mIt.GoToBegin( ); !mIt.IsAtEnd( ); ++mIt )
228 // -------------------------------------------------------------------------
229 template< class _TInputImage, class _TDistanceMap >
230 void fpa::Image::SkeletonFilter< _TInputImage, _TDistanceMap >::
232 std::vector< TIndex >& end_points,
233 const TOutputImage* dmap,
235 const _TSkeletonQueue& queue
238 typedef typename _TSkeletonQueue::value_type _TSkeletonQueueValue;
241 typedef itk::Image< bool, Self::Dimension > _TMarks;
242 typename _TMarks::Pointer marks = _TMarks::New( );
243 marks->SetLargestPossibleRegion( mst->GetLargestPossibleRegion( ) );
244 marks->SetRequestedRegion( mst->GetRequestedRegion( ) );
245 marks->SetBufferedRegion( mst->GetBufferedRegion( ) );
246 marks->SetSpacing( mst->GetSpacing( ) );
247 marks->SetOrigin( mst->GetOrigin( ) );
248 marks->SetDirection( mst->GetDirection( ) );
250 marks->FillBuffer( false );
252 // Get candidates in maximum to minimum iteration
253 typename _TSkeletonQueue::const_reverse_iterator nIt = queue.rbegin( );
254 for( ; nIt != queue.rend( ); ++nIt )
256 // Mark it and update end-points
257 if( !( marks->GetPixel( nIt->second ) ) )
259 marks->SetPixel( nIt->second, true );
260 end_points.push_back( nIt->second );
263 TIndex it = nIt->second;
264 TIndex p = mst->GetParent( it );
267 this->_MarkSphere( marks, dmap, it );
269 p = mst->GetParent( it );
272 this->_MarkSphere( marks, dmap, it );
282 this->m_DistanceMap = TDistanceMap::New( );
283 this->m_DistanceMap->InsideIsPositiveOn( );
284 this->m_DistanceMap->SquaredDistanceOff( );
285 this->m_DistanceMap->UseImageSpacingOn( );
287 template< class _TImage, class _TScalar >
288 void fpa::Image::SkeletonFilter< _TImage, _TScalar >::
289 _Skeleton( const std::vector< TVertex >& end_points, _TAdjacencies& A )
291 typedef typename TSkeleton::TPath _TPath;
292 typedef itk::Image< unsigned long, TImage::ImageDimension > _TTagsImage;
294 TMST* mst = this->GetMinimumSpanningTree( );
295 TSkeleton* skeleton = this->GetSkeleton( );
298 typename _TTagsImage::Pointer tags = _TTagsImage::New( );
299 tags->SetLargestPossibleRegion( mst->GetLargestPossibleRegion( ) );
300 tags->SetRequestedRegion( mst->GetRequestedRegion( ) );
301 tags->SetBufferedRegion( mst->GetBufferedRegion( ) );
303 tags->FillBuffer( 0 );
304 typename std::vector< TVertex >::const_iterator eIt = end_points.begin( );
305 for( ; eIt != end_points.end( ); ++eIt )
308 TVertex p = mst->GetParent( it );
311 tags->SetPixel( it, tags->GetPixel( it ) + 1 );
313 p = mst->GetParent( it );
316 tags->SetPixel( it, tags->GetPixel( it ) + 1 );
320 // Build paths (branches)
321 eIt = end_points.begin( );
322 for( ; eIt != end_points.end( ); ++eIt )
325 TVertex p = mst->GetParent( it );
327 typename _TPath::Pointer path = _TPath::New( );
328 path->SetReferenceImage( mst );
331 if( tags->GetPixel( sIdx ) != tags->GetPixel( it ) )
333 // Ok, a new branch has been added
334 path->AddVertex( it );
335 skeleton->AddBranch( path );
337 // Update a new starting index
338 path = _TPath::New( );
339 path->SetReferenceImage( mst );
343 path->AddVertex( it );
345 p = mst->GetParent( it );
349 // Finally, add last branch
350 path->AddVertex( it );
351 skeleton->AddBranch( path );
357 #endif // __fpa__Image__SkeletonFilter__hxx__