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__
9 #include <itkMinimumMaximumImageCalculator.h>
11 // -------------------------------------------------------------------------
12 template< class _TImage, class _TScalar >
13 void fpa::Image::SkeletonFilter< _TImage, _TScalar >::
14 SetInput( const TScalarImage* image )
19 // -------------------------------------------------------------------------
20 template< class _TImage, class _TScalar >
21 void fpa::Image::SkeletonFilter< _TImage, _TScalar >::
22 SetInput( const TImage* image )
24 this->m_DistanceMap->SetInput( image );
25 this->Superclass::SetInput( this->m_DistanceMap->GetOutput( ) );
28 // -------------------------------------------------------------------------
29 template< class _TImage, class _TScalar >
30 _TImage* fpa::Image::SkeletonFilter< _TImage, _TScalar >::
33 return( this->m_DistanceMap->GetInput( ) );
36 // -------------------------------------------------------------------------
37 template< class _TImage, class _TScalar >
38 const _TImage* fpa::Image::SkeletonFilter< _TImage, _TScalar >::
41 return( this->m_DistanceMap->GetInput( ) );
44 // -------------------------------------------------------------------------
45 template< class _TImage, class _TScalar >
46 typename fpa::Image::SkeletonFilter< _TImage, _TScalar >::
47 TSkeleton* fpa::Image::SkeletonFilter< _TImage, _TScalar >::
51 dynamic_cast< TSkeleton* >(
52 this->itk::ProcessObject::GetOutput( this->m_SkeletonIdx )
57 // -------------------------------------------------------------------------
58 template< class _TImage, class _TScalar >
59 typename fpa::Image::SkeletonFilter< _TImage, _TScalar >::
60 TMarks* fpa::Image::SkeletonFilter< _TImage, _TScalar >::
64 dynamic_cast< TMarks* >(
65 this->itk::ProcessObject::GetOutput( this->m_MarksIdx )
70 // -------------------------------------------------------------------------
71 template< class _TImage, class _TScalar >
72 fpa::Image::SkeletonFilter< _TImage, _TScalar >::
75 m_SeedFromMaximumDistance( false )
77 this->m_DistanceMap = TDistanceMap::New( );
78 this->m_DistanceMap->InsideIsPositiveOn( );
79 this->m_DistanceMap->SquaredDistanceOff( );
80 this->m_DistanceMap->UseImageSpacingOn( );
82 unsigned int nOutputs = this->GetNumberOfRequiredOutputs( );
83 this->SetNumberOfRequiredOutputs( nOutputs + 2 );
84 this->m_SkeletonIdx = nOutputs;
85 this->m_MarksIdx = nOutputs + 1;
87 typename TSkeleton::Pointer skeleton = TSkeleton::New( );
88 typename TMarks::Pointer marks = TMarks::New( );
89 this->SetNthOutput( this->m_SkeletonIdx, skeleton.GetPointer( ) );
90 this->SetNthOutput( this->m_MarksIdx, marks.GetPointer( ) );
93 // -------------------------------------------------------------------------
94 template< class _TImage, class _TScalar >
95 fpa::Image::SkeletonFilter< _TImage, _TScalar >::
100 // -------------------------------------------------------------------------
101 template< class _TImage, class _TScalar >
102 void fpa::Image::SkeletonFilter< _TImage, _TScalar >::
105 // Prepare distance map
106 this->m_DistanceMap->Update( );
110 if( this->m_SeedFromMaximumDistance )
112 typedef itk::MinimumMaximumImageCalculator< TScalarImage > _TMinMax;
113 typename _TMinMax::Pointer minmax = _TMinMax::New( );
114 minmax->SetImage( this->m_DistanceMap->GetOutput( ) );
116 seed = minmax->GetIndexOfMaximum( );
119 seed = *( this->BeginSeeds( ) );
120 this->m_Seeds.clear( );
121 this->m_Seeds.insert( seed );
123 // Prepare skeleton candidates queue
124 this->m_SkeletonQueue.clear( );
127 this->Superclass::GenerateData( );
131 std::vector< TVertex > end_points;
132 this->_EndPoints( end_points, A );
133 this->_Skeleton( end_points, A );
136 // -------------------------------------------------------------------------
137 template< class _TImage, class _TScalar >
138 void fpa::Image::SkeletonFilter< _TImage, _TScalar >::
139 _SetOutputValue( const TVertex& vertex, const TOutputValue& value )
142 typedef typename _TSkeletonQueue::value_type _TSkeletonQueueValue;
144 this->Superclass::_UpdateResult( n );
145 double d = double( this->GetInput( )->GetPixel( n.Vertex ) );
146 if( d >= double( 0 ) )
148 // Update skeleton candidates
150 double v = double( n.Result ) / ( d * d );
151 this->m_SkeletonQueue.insert( _TSkeletonQueueValue( v, n.Vertex ) );
157 // -------------------------------------------------------------------------
158 template< class _TImage, class _TScalar >
159 void fpa::Image::SkeletonFilter< _TImage, _TScalar >::
160 _EndPoints( std::vector< TVertex >& end_points, _TAdjacencies& A )
163 auto marks = this->GetMarks( );
164 auto mst = this->GetMinimumSpanningTree( );
165 auto spac = marks->GetSpacing( );
168 marks->SetLargestPossibleRegion( mst->GetLargestPossibleRegion( ) );
169 marks->SetRequestedRegion( mst->GetRequestedRegion( ) );
170 marks->SetBufferedRegion( mst->GetBufferedRegion( ) );
171 marks->SetSpacing( mst->GetSpacing( ) );
172 marks->SetOrigin( mst->GetOrigin( ) );
173 marks->SetDirection( mst->GetDirection( ) );
175 marks->FillBuffer( 0 );
177 // BFS from maximum queue
178 while( this->m_SkeletonQueue.size( ) > 0 )
181 auto nIt = this->m_SkeletonQueue.begin( );
183 this->m_SkeletonQueue.erase( nIt );
185 // Mark it and update end-points
186 unsigned char m = marks->GetPixel( n.second );
189 marks->SetPixel( n.second, 1 );
190 end_points.push_back( n.second );
193 TVertex it = n.second;
194 TVertex p = mst->GetParent( it );
197 this->_MarkSphere( it );
199 p = mst->GetParent( it );
202 this->_MarkSphere( it );
209 // -------------------------------------------------------------------------
210 template< class _TImage, class _TScalar >
211 void fpa::Image::SkeletonFilter< _TImage, _TScalar >::
212 _Skeleton( const std::vector< TVertex >& end_points, _TAdjacencies& A )
215 typedef itk::Image< unsigned long, Self::Dimension > _TTagsImage;
216 typedef typename TMST::TPath _TPath;
218 auto mst = this->GetMinimumSpanningTree( );
219 auto skeleton = this->GetSkeleton( );
222 typename _TTagsImage::Pointer tags = _TTagsImage::New( );
223 tags->SetLargestPossibleRegion( mst->GetLargestPossibleRegion( ) );
224 tags->SetRequestedRegion( mst->GetRequestedRegion( ) );
225 tags->SetBufferedRegion( mst->GetBufferedRegion( ) );
227 tags->FillBuffer( 0 );
228 for( auto eIt = end_points.begin( ); eIt != end_points.end( ); ++eIt )
231 TVertex p = mst->GetParent( it );
234 tags->SetPixel( it, tags->GetPixel( it ) + 1 );
236 p = mst->GetParent( it );
239 tags->SetPixel( it, tags->GetPixel( it ) + 1 );
243 // Build paths (branches)
244 for( auto eIt = end_points.begin( ); eIt != end_points.end( ); ++eIt )
247 TVertex p = mst->GetParent( it );
249 typename _TPath::Pointer path = _TPath::New( );
250 path->SetReferenceImage( mst );
253 if( tags->GetPixel( sIdx ) != tags->GetPixel( it ) )
255 // Ok, a new branch has been added
256 path->AddVertex( it );
257 skeleton->AddBranch( path );
259 // Update a new starting index
260 path = _TPath::New( );
261 path->SetReferenceImage( mst );
265 path->AddVertex( it );
267 p = mst->GetParent( it );
271 // Finally, add last branch
272 path->AddVertex( it );
273 skeleton->AddBranch( path );
279 // -------------------------------------------------------------------------
280 template< class _TImage, class _TScalar >
281 void fpa::Image::SkeletonFilter< _TImage, _TScalar >::
282 _MarkSphere( const TVertex& idx )
285 typedef itk::ImageRegionIteratorWithIndex< TMarks > _TMarksIt;
287 static const double _eps = std::sqrt( double( Self::Dimension + 1 ) );
288 auto input = this->GetInput( );
289 auto marks = this->GetMarks( );
290 auto spac = input->GetSpacing( );
291 auto region = input->GetRequestedRegion( );
293 typename _TImage::PointType cnt;
294 input->TransformIndexToPhysicalPoint( idx, cnt );
295 double r = double( input->GetPixel( idx ) ) * _eps;
298 for( unsigned int d = 0; d < Self::Dimension; ++d )
300 long off = long( std::ceil( r / double( spac[ d ] ) ) );
303 i0[ d ] = idx[ d ] - off;
304 i1[ d ] = idx[ d ] + off;
306 if( i0[ d ] < region.GetIndex( )[ d ] )
307 i0[ d ] = region.GetIndex( )[ d ];
309 if( i1[ d ] >= region.GetIndex( )[ d ] + region.GetSize( )[ d ] )
310 i1[ d ] = region.GetIndex( )[ d ] + region.GetSize( )[ d ] - 1;
314 typename _TImage::SizeType size;
315 for( unsigned int d = 0; d < Self::Dimension; ++d )
316 size[ d ] = i1[ d ] - i0[ d ] + 1;
318 typename _TImage::RegionType neighRegion;
319 neighRegion.SetIndex( i0 );
320 neighRegion.SetSize( size );
322 _TMarksIt mIt( marks, neighRegion );
323 for( mIt.GoToBegin( ); !mIt.IsAtEnd( ); ++mIt )
325 TVertex w = mIt.GetIndex( );
326 typename _TImage::PointType p;
327 marks->TransformIndexToPhysicalPoint( w, p );
334 #endif // __fpa__Image__SkeletonFilter__hxx__