]> Creatis software - clitk.git/blobdiff - segmentation/clitkExtractLungFilter.txx
Use MultipleBSplineDeformableTransform instead of BSplineDeformableTransform in
[clitk.git] / segmentation / clitkExtractLungFilter.txx
index 4baee45296f5555d49b1748195b19d3757106e13..52276f4478bb0cd55a6040efd07a763bd291d120 100644 (file)
@@ -24,6 +24,8 @@
 #include "clitkSetBackgroundImageFilter.h"
 #include "clitkSegmentationUtils.h"
 #include "clitkAutoCropFilter.h"
+#include "clitkCropLikeImageFilter.h"
+#include "clitkFillMaskFilter.h"
 
 // itk
 #include "itkBinaryThresholdImageFilter.h"
 #include "itkOtsuThresholdImageFilter.h"
 #include "itkBinaryThinningImageFilter3D.h"
 #include "itkImageIteratorWithIndex.h"
-
+#include "itkBinaryMorphologicalOpeningImageFilter.h"
+#include "itkBinaryMorphologicalClosingImageFilter.h"
 
 //--------------------------------------------------------------------
-template <class ImageType, class MaskImageType>
-clitk::ExtractLungFilter<ImageType, MaskImageType>::
+template <class ImageType>
+clitk::ExtractLungFilter<ImageType>::
 ExtractLungFilter():
   clitk::FilterBase(),
+  clitk::FilterWithAnatomicalFeatureDatabaseManagement(),
   itk::ImageToImageFilter<ImageType, MaskImageType>()
 {
   SetNumberOfSteps(10);
   m_MaxSeedNumber = 500;
 
   // Default global options
-  this->SetNumberOfRequiredInputs(2);
+  this->SetNumberOfRequiredInputs(1);
   SetPatientMaskBackgroundValue(0);
   SetBackgroundValue(0); // Must be zero
   SetForegroundValue(1);
@@ -65,6 +69,7 @@ ExtractLungFilter():
   SetUpperThresholdForTrachea(-900);
   SetMultiplierForTrachea(5);
   SetThresholdStepSizeForTrachea(64);
+  SetNumberOfSlicesToSkipBeforeSearchingSeed(0);
   
   // Step 3 default values
   SetNumberOfHistogramBins(500);
@@ -82,16 +87,20 @@ ExtractLungFilter():
   p3->UseLastKeepOff();
   SetLabelizeParameters3(p3);
   
-  // Step 5 : find bronchial bifurcations
-  FindBronchialBifurcationsOn();
+  // Step 5
+  OpenCloseOff();
+  SetOpenCloseRadius(1);
+  
+  // Step 6
+  FillHolesOn();
 }
 //--------------------------------------------------------------------
 
 
 //--------------------------------------------------------------------
-template <class ImageType, class MaskImageType>
+template <class ImageType>
 void 
-clitk::ExtractLungFilter<ImageType, MaskImageType>::
+clitk::ExtractLungFilter<ImageType>::
 SetInput(const ImageType * image) 
 {
   this->SetNthInput(0, const_cast<ImageType *>(image));
@@ -100,21 +109,9 @@ SetInput(const ImageType * image)
 
 
 //--------------------------------------------------------------------
-template <class ImageType, class MaskImageType>
-void 
-clitk::ExtractLungFilter<ImageType, MaskImageType>::
-SetInputPatientMask(MaskImageType * image, MaskImagePixelType bg ) 
-{
-  this->SetNthInput(1, const_cast<MaskImageType *>(image));
-  SetPatientMaskBackgroundValue(bg);
-}
-//--------------------------------------------------------------------
-
-
-//--------------------------------------------------------------------
-template <class ImageType, class MaskImageType>
+template <class ImageType>
 void 
-clitk::ExtractLungFilter<ImageType, MaskImageType>::
+clitk::ExtractLungFilter<ImageType>::
 AddSeed(InternalIndexType s) 
 { 
   m_Seeds.push_back(s);
@@ -123,10 +120,10 @@ AddSeed(InternalIndexType s)
 
 
 //--------------------------------------------------------------------
-template <class ImageType, class MaskImageType>
+template <class ImageType>
 template<class ArgsInfoType>
 void 
-clitk::ExtractLungFilter<ImageType, MaskImageType>::
+clitk::ExtractLungFilter<ImageType>::
 SetArgsInfo(ArgsInfoType mArgsInfo)
 {
   SetVerboseOption_GGO(mArgsInfo);
@@ -134,8 +131,13 @@ SetArgsInfo(ArgsInfoType mArgsInfo)
   SetWriteStep_GGO(mArgsInfo);
   SetVerboseWarningOff_GGO(mArgsInfo);
 
+  SetAFDBFilename_GGO(mArgsInfo);
+  SetOutputLungFilename_GGO(mArgsInfo);
+  SetOutputTracheaFilename_GGO(mArgsInfo);
+
   SetUpperThreshold_GGO(mArgsInfo);
   SetLowerThreshold_GGO(mArgsInfo);
+  SetNumberOfSlicesToSkipBeforeSearchingSeed_GGO(mArgsInfo);
   SetLabelizeParameters1_GGO(mArgsInfo);
   if (!mArgsInfo.remove1_given) {
     GetLabelizeParameters1()->AddLabelToRemove(2); 
@@ -154,44 +156,57 @@ SetArgsInfo(ArgsInfoType mArgsInfo)
 
   SetRadiusForTrachea_GGO(mArgsInfo);
   SetLabelizeParameters3_GGO(mArgsInfo);
+  
+  SetOpenCloseRadius_GGO(mArgsInfo);
+  SetOpenClose_GGO(mArgsInfo);
+  
+  SetFillHoles_GGO(mArgsInfo);
 }
 //--------------------------------------------------------------------
 
 
 //--------------------------------------------------------------------
-template <class ImageType, class MaskImageType>
+template <class ImageType>
 void 
-clitk::ExtractLungFilter<ImageType, MaskImageType>::
+clitk::ExtractLungFilter<ImageType>::
 GenerateOutputInformation() 
 { 
   Superclass::GenerateOutputInformation();
-  //this->GetOutput(0)->SetRequestedRegion(this->GetOutput(0)->GetLargestPossibleRegion());
+  
+  // Read DB
+  LoadAFDB();
 
   // Get input pointers
-  patient = dynamic_cast<const MaskImageType*>(itk::ProcessObject::GetInput(1));
   input   = dynamic_cast<const ImageType*>(itk::ProcessObject::GetInput(0));
+  patient = GetAFDB()->template GetImage <MaskImageType>("patient");  
 
-  // Check image
-  if (!HaveSameSizeAndSpacing<ImageType, MaskImageType>(input, patient)) {
-    this->SetLastError("* ERROR * the images (input and patient mask) must have the same size & spacing");
-    return;
-  }
-  
   //--------------------------------------------------------------------
   //--------------------------------------------------------------------
-  StartNewStepOrStop("Set background to initial image");
+  // Crop input like patient image (must have the same spacing)
+  StartNewStep("Crop input image to 'patient' extends");
+  typedef clitk::CropLikeImageFilter<ImageType> CropImageFilter;
+  typename CropImageFilter::Pointer cropFilter = CropImageFilter::New();
+  cropFilter->SetInput(input);
+  cropFilter->SetCropLikeImage(patient);
+  cropFilter->Update();
+  working_input = cropFilter->GetOutput();
+  DD(working_input->GetLargestPossibleRegion());
+  StopCurrentStep<ImageType>(working_input);
+  //--------------------------------------------------------------------
+  //--------------------------------------------------------------------
+  StartNewStep("Set background to initial image");
   working_input = SetBackground<ImageType, MaskImageType>
-    (input, patient, GetPatientMaskBackgroundValue(), -1000);
+    (working_input, patient, GetPatientMaskBackgroundValue(), -1000);
   StopCurrentStep<ImageType>(working_input);
 
   //--------------------------------------------------------------------
   //--------------------------------------------------------------------
-  StartNewStepOrStop("Remove Air");
+  StartNewStep("Remove Air");
   // Check threshold
   if (m_UseLowerThreshold) {
     if (m_LowerThreshold > m_UpperThreshold) {
-      this->SetLastError("ERROR: lower threshold cannot be greater than upper threshold.");
-      return;
+      clitkExceptionMacro("lower threshold cannot be greater than upper threshold.");
     }
   }
   // Threshold to get air
@@ -228,61 +243,12 @@ GenerateOutputInformation()
 
   //--------------------------------------------------------------------
   //--------------------------------------------------------------------
-  StartNewStepOrStop("Find the trachea");
-  if (m_Seeds.size() == 0) { // try to find seed
-    // Search seed (parameters = UpperThresholdForTrachea)
-    static const unsigned int Dim = ImageType::ImageDimension;
-    typename InternalImageType::RegionType sliceRegion = working_input->GetLargestPossibleRegion();
-    typename InternalImageType::SizeType sliceRegionSize = sliceRegion.GetSize();
-    typename InternalImageType::IndexType sliceRegionIndex = sliceRegion.GetIndex();
-    sliceRegionIndex[Dim-1]=sliceRegionSize[Dim-1]-5;
-    sliceRegionSize[Dim-1]=5;
-    sliceRegion.SetSize(sliceRegionSize);
-    sliceRegion.SetIndex(sliceRegionIndex);
-    typedef  itk::ImageRegionConstIterator<ImageType> IteratorType;
-    IteratorType it(working_input, sliceRegion);
-    it.GoToBegin();
-    while (!it.IsAtEnd()) {
-      if(it.Get() < GetUpperThresholdForTrachea() ) {
-        AddSeed(it.GetIndex());
-      }
-      ++it;
-    }
-  }
-  
-  if (m_Seeds.size() != 0) {
-    // Explosion controlled region growing
-    typedef clitk::ExplosionControlledThresholdConnectedImageFilter<ImageType, InternalImageType> ImageFilterType;
-    typename ImageFilterType::Pointer f= ImageFilterType::New();
-    f->SetInput(working_input);
-    f->SetVerbose(false);
-    f->SetLower(-2000);
-    f->SetUpper(GetUpperThresholdForTrachea());
-    f->SetMinimumLowerThreshold(-2000);
-    f->SetMaximumUpperThreshold(0);
-    f->SetAdaptLowerBorder(false);
-    f->SetAdaptUpperBorder(true);
-    f->SetMinimumSize(5000); 
-    f->SetReplaceValue(1);
-    f->SetMultiplier(GetMultiplierForTrachea());
-    f->SetThresholdStepSize(GetThresholdStepSizeForTrachea());
-    f->SetMinimumThresholdStepSize(1);
-    for(unsigned int i=0; i<m_Seeds.size();i++) {
-      f->AddSeed(m_Seeds[i]);
-    }  
-    f->Update();
-    trachea_tmp = f->GetOutput();
-    // Set output
-    StopCurrentStep<InternalImageType>(trachea_tmp);
-  }
-  else { // Trachea not found
-    this->SetWarning("* WARNING * No seed found for trachea.");
-    StopCurrentStep();
-  }
+  StartNewStep("Search for the trachea");
+  SearchForTrachea();
 
   //--------------------------------------------------------------------
   //--------------------------------------------------------------------
-  StartNewStepOrStop("Extract the lung with Otsu filter");
+  StartNewStep("Extract the lung with Otsu filter");
   // Automated Otsu thresholding and relabeling
   typedef itk::OtsuThresholdImageFilter<ImageType,InternalImageType> OtsuThresholdImageFilterType;
   typename OtsuThresholdImageFilterType::Pointer otsuFilter=OtsuThresholdImageFilterType::New();
@@ -298,7 +264,7 @@ GenerateOutputInformation()
 
   //--------------------------------------------------------------------
   //--------------------------------------------------------------------
-  StartNewStepOrStop("Select labels");
+  StartNewStep("Select labels");
   // Keep right labels
   working_image = LabelizeAndSelectLabels<InternalImageType>
     (working_image, 
@@ -314,12 +280,12 @@ GenerateOutputInformation()
   //--------------------------------------------------------------------
   //--------------------------------------------------------------------
   if (m_Seeds.size() != 0) { // if ==0 ->no trachea found
-    StartNewStepOrStop("Remove the trachea");
+    StartNewStep("Remove the trachea");
     // Set the trachea
     working_image = SetBackground<InternalImageType, InternalImageType>
       (working_image, trachea_tmp, 1, -1);
   
-   // Dilate the trachea 
+    // Dilate the trachea 
     static const unsigned int Dim = ImageType::ImageDimension;
     typedef itk::BinaryBallStructuringElement<InternalPixelType, Dim> KernelType;
     KernelType structuringElement;
@@ -358,15 +324,15 @@ GenerateOutputInformation()
 
   //--------------------------------------------------------------------
   //--------------------------------------------------------------------
-  typedef clitk::AutoCropFilter<InternalImageType> CropFilterType;
-  typename CropFilterType::Pointer cropFilter = CropFilterType::New();
+  typedef clitk::AutoCropFilter<InternalImageType> AutoCropFilterType;
+  typename AutoCropFilterType::Pointer autocropFilter = AutoCropFilterType::New();
   if (m_Seeds.size() != 0) { // if ==0 ->no trachea found
-    StartNewStepOrStop("Croping trachea");
-    cropFilter->SetInput(trachea_tmp);
-    cropFilter->Update(); // Needed
+    StartNewStep("Cropping trachea");
+    autocropFilter->SetInput(trachea_tmp);
+    autocropFilter->Update(); // Needed
     typedef itk::CastImageFilter<InternalImageType, MaskImageType> CastImageFilterType;
     typename CastImageFilterType::Pointer caster= CastImageFilterType::New();
-    caster->SetInput(cropFilter->GetOutput());
+    caster->SetInput(autocropFilter->GetOutput());
     caster->Update();   
     trachea = caster->GetOutput();
     StopCurrentStep<MaskImageType>(trachea);  
@@ -374,16 +340,63 @@ GenerateOutputInformation()
 
   //--------------------------------------------------------------------
   //--------------------------------------------------------------------
-  StartNewStepOrStop("Croping lung");
-  typename CropFilterType::Pointer cropFilter2 = CropFilterType::New(); // Needed to reset pipeline
-  cropFilter2->SetInput(working_image);
-  cropFilter2->Update();   
-  working_image = cropFilter2->GetOutput();
+  StartNewStep("Cropping lung");
+  typename AutoCropFilterType::Pointer autocropFilter2 = AutoCropFilterType::New(); // Needed to reset pipeline
+  autocropFilter2->SetInput(working_image);
+  autocropFilter2->Update();   
+  working_image = autocropFilter2->GetOutput();
+  DD(working_image->GetLargestPossibleRegion());
   StopCurrentStep<InternalImageType>(working_image);
 
   //--------------------------------------------------------------------
   //--------------------------------------------------------------------
-  StartNewStepOrStop("Separate Left/Right lungs");
+  // Final OpenClose
+  if (GetOpenClose()) {
+    StartNewStep("Open/Close"); 
+
+    // Structuring element
+    typedef itk::BinaryBallStructuringElement<InternalPixelType, ImageDimension> KernelType;
+    KernelType structuringElement;
+    structuringElement.SetRadius(GetOpenCloseRadius());
+    structuringElement.CreateStructuringElement();
+       
+    // Open
+    typedef itk::BinaryMorphologicalOpeningImageFilter<InternalImageType, InternalImageType, KernelType> OpenFilterType;
+    typename OpenFilterType::Pointer openFilter = OpenFilterType::New();
+    openFilter->SetInput(working_image);
+    openFilter->SetBackgroundValue(GetBackgroundValue());
+    openFilter->SetForegroundValue(GetForegroundValue());
+    openFilter->SetKernel(structuringElement);
+       
+    // Close
+    typedef itk::BinaryMorphologicalClosingImageFilter<InternalImageType, InternalImageType, KernelType> CloseFilterType;
+    typename CloseFilterType::Pointer closeFilter = CloseFilterType::New();
+    closeFilter->SetInput(openFilter->GetOutput());
+    closeFilter->SetSafeBorder(true);
+    closeFilter->SetForegroundValue(GetForegroundValue());
+    closeFilter->SetKernel(structuringElement);
+    closeFilter->Update();
+    working_image = closeFilter->GetOutput();
+  }
+
+  //--------------------------------------------------------------------
+  //--------------------------------------------------------------------
+  // Fill Lungs
+  if (GetFillHoles()) {
+    StartNewStep("Fill Holes");
+    typedef clitk::FillMaskFilter<InternalImageType> FillMaskFilterType;
+    typename FillMaskFilterType::Pointer fillMaskFilter = FillMaskFilterType::New();
+    fillMaskFilter->SetInput(working_image);
+    fillMaskFilter->AddDirection(2);
+    //fillMaskFilter->AddDirection(1);
+    fillMaskFilter->Update();   
+    working_image = fillMaskFilter->GetOutput();
+    StopCurrentStep<InternalImageType>(working_image);
+  }
+
+  //--------------------------------------------------------------------
+  //--------------------------------------------------------------------
+  StartNewStep("Separate Left/Right lungs");
   // Initial label
   working_image = Labelize<InternalImageType>(working_image, 
                                               GetBackgroundValue(), 
@@ -401,13 +414,14 @@ GenerateOutputInformation()
   // Decompose the first label
   static const unsigned int Dim = ImageType::ImageDimension;
   if (initialNumberOfLabels<2) {
+    DD(initialNumberOfLabels);
     // Structuring element radius
     typename ImageType::SizeType radius;
     for (unsigned int i=0;i<Dim;i++) radius[i]=1;
     typedef clitk::DecomposeAndReconstructImageFilter<InternalImageType,InternalImageType> DecomposeAndReconstructFilterType;
     typename DecomposeAndReconstructFilterType::Pointer decomposeAndReconstructFilter=DecomposeAndReconstructFilterType::New();
     decomposeAndReconstructFilter->SetInput(working_image);
-    decomposeAndReconstructFilter->SetVerbose(false);
+    decomposeAndReconstructFilter->SetVerbose(true);
     decomposeAndReconstructFilter->SetRadius(radius);
     decomposeAndReconstructFilter->SetMaximumNumberOfLabels(2);
     decomposeAndReconstructFilter->SetMinimumObjectSize(this->GetMinimalComponentSize());
@@ -420,7 +434,7 @@ GenerateOutputInformation()
     working_image = decomposeAndReconstructFilter->GetOutput();      
   }
 
-  // Retain labels (lungs)
+  // Retain labels ('1' is largset lung, so right. '2' is left)
   typedef itk::ThresholdImageFilter<InternalImageType> ThresholdImageFilterType;
   typename ThresholdImageFilterType::Pointer thresholdFilter = ThresholdImageFilterType::New();
   thresholdFilter->SetInput(working_image);
@@ -431,7 +445,7 @@ GenerateOutputInformation()
   StopCurrentStep<InternalImageType> (working_image);
   
   // Final Cast 
-  StartNewStepOrStop("Final cast"); 
+  StartNewStep("Cast the lung mask"); 
   typedef itk::CastImageFilter<InternalImageType, MaskImageType> CastImageFilterType;
   typename CastImageFilterType::Pointer caster= CastImageFilterType::New();
   caster->SetInput(working_image);
@@ -440,142 +454,193 @@ GenerateOutputInformation()
 
   // Update output info
   this->GetOutput(0)->SetRegions(output->GetLargestPossibleRegion());
+}
+//--------------------------------------------------------------------
 
-  // Try to extract bifurcation in the trachea (bronchi)
-  // STILL EXPERIMENTAL
-  if (GetFindBronchialBifurcations()) {
-    StartNewStepOrStop("Find bronchial bifurcations");
-    // Step 1 : extract skeleton
-    // Define the thinning filter
-    typedef itk::BinaryThinningImageFilter3D<MaskImageType, MaskImageType> ThinningFilterType;
-    typename ThinningFilterType::Pointer thinningFilter = ThinningFilterType::New();
-    thinningFilter->SetInput(trachea);
-    thinningFilter->Update();
-    typename MaskImageType::Pointer skeleton = thinningFilter->GetOutput();
-    writeImage<MaskImageType>(skeleton, "skeleton.mhd");
-
-    // Step 2 : tracking
-    DD("tracking");
-    
-    // Step 2.1 : find first point for tracking
-    typedef itk::ImageRegionConstIteratorWithIndex<MaskImageType> IteratorType;
-    IteratorType it(skeleton, skeleton->GetLargestPossibleRegion());
-    it.GoToReverseBegin();
-    while ((!it.IsAtEnd()) && (it.Get() == GetBackgroundValue())) { 
-      --it;
-    }
-    if (it.IsAtEnd()) {
-      this->SetLastError("ERROR: first point in the skeleton not found ! Abort");
-      return;
-    }
-    DD(skeleton->GetLargestPossibleRegion().GetIndex());
-    typename MaskImageType::IndexType index = it.GetIndex();
-    DD(index);
-    
-    // Step 2.2 : initialize neighborhooditerator
-    typedef itk::NeighborhoodIterator<MaskImageType> NeighborhoodIteratorType;
-    typename NeighborhoodIteratorType::SizeType radius;
-    radius.Fill(1);
-    NeighborhoodIteratorType nit(radius, skeleton, skeleton->GetLargestPossibleRegion());
-    DD(nit.GetSize());
-    DD(nit.Size());
-    
-    // Find first label number (must be different from BG and FG)
-    typename MaskImageType::PixelType label = GetForegroundValue()+1;
-    while ((label == GetBackgroundValue()) || (label == GetForegroundValue())) { label++; }
-    DD(label);
-
-    // Track from the first point
-    std::vector<BifurcationType> listOfBifurcations;
-    TrackFromThisIndex(listOfBifurcations, skeleton, index, label);
-    DD("end track");
-    DD(listOfBifurcations.size());
-    writeImage<MaskImageType>(skeleton, "skeleton2.mhd");
-
-    for(unsigned int i=0; i<listOfBifurcations.size(); i++) {
-      typename MaskImageType::PointType p;
-      skeleton->TransformIndexToPhysicalPoint(listOfBifurcations[i].index, p);
-      DD(p);
-    }
 
-  }
+//--------------------------------------------------------------------
+template <class ImageType>
+void 
+clitk::ExtractLungFilter<ImageType>::
+GenerateData() 
+{
+  // Set the output
+  this->GraftOutput(output); // not SetNthOutput
+  // Store image filenames into AFDB 
+  GetAFDB()->SetImageFilename("lungs", this->GetOutputLungFilename());  
+  GetAFDB()->SetImageFilename("trachea", this->GetOutputTracheaFilename());  
+  WriteAFDB();
 }
 //--------------------------------------------------------------------
 
 
 //--------------------------------------------------------------------
-template <class ImageType, class MaskImageType>
+template <class ImageType>
+bool 
+clitk::ExtractLungFilter<ImageType>::
+SearchForTracheaSeed(int skip)
+{
+  if (m_Seeds.size() == 0) { // try to find seed (if not zero, it is given by user)    
+    // Restart the search until a seed is found, skipping more and more slices
+    bool stop = false;
+    while (!stop) {
+      // Search seed (parameters = UpperThresholdForTrachea)
+      static const unsigned int Dim = ImageType::ImageDimension;
+      typename InternalImageType::RegionType sliceRegion = working_input->GetLargestPossibleRegion();
+      typename InternalImageType::SizeType sliceRegionSize = sliceRegion.GetSize();
+      typename InternalImageType::IndexType sliceRegionIndex = sliceRegion.GetIndex();
+      sliceRegionIndex[Dim-1]=sliceRegionSize[Dim-1]-skip-5;
+      sliceRegionSize[Dim-1]=5;
+      sliceRegion.SetSize(sliceRegionSize);
+      sliceRegion.SetIndex(sliceRegionIndex);
+      typedef  itk::ImageRegionConstIterator<ImageType> IteratorType;
+      IteratorType it(working_input, sliceRegion);
+      it.GoToBegin();
+      while (!it.IsAtEnd()) {
+        if(it.Get() < GetUpperThresholdForTrachea() ) {
+          AddSeed(it.GetIndex());
+          // DD(it.GetIndex());
+        }
+        ++it;
+      }
+      
+      // if we do not found : restart
+      stop = (m_Seeds.size() != 0);
+      if (!stop) {
+       if (GetVerboseStep()) {
+         std::cout << "\t No seed found this time. I skip some slices and restart." << std::endl;
+       }
+        if (skip > 0.5 * working_input->GetLargestPossibleRegion().GetSize()[2]) {
+          // we want to skip more than a half of the image, it is probably a bug
+          std::cerr << "Number of slices to skip to find trachea to high = " << skip << std::endl;
+          stop = true;
+        }
+        skip += 5;
+      }
+    }
+  }
+  return (m_Seeds.size() != 0);
+}
+//--------------------------------------------------------------------
+
+  
+//--------------------------------------------------------------------
+template <class ImageType>
 void 
-clitk::ExtractLungFilter<ImageType, MaskImageType>::
-GenerateData() {
-  // Do not put some "startnewstep" here, because the object if
-  // modified and the filter's pipeline it do two times. But it is
-  // required to quit if MustStop was set before.
-  if (GetMustStop()) return;
+clitk::ExtractLungFilter<ImageType>::
+TracheaRegionGrowing()
+{
+  // Explosion controlled region growing
+  typedef clitk::ExplosionControlledThresholdConnectedImageFilter<ImageType, InternalImageType> ImageFilterType;
+  typename ImageFilterType::Pointer f= ImageFilterType::New();
+  f->SetInput(working_input);
+  f->SetVerbose(false);
+  f->SetLower(-2000);
+  f->SetUpper(GetUpperThresholdForTrachea());
+  f->SetMinimumLowerThreshold(-2000);
+  //  f->SetMaximumUpperThreshold(0); // MAYBE TO CHANGE ???
+  f->SetMaximumUpperThreshold(-800); // MAYBE TO CHANGE ???
+  f->SetAdaptLowerBorder(false);
+  f->SetAdaptUpperBorder(true);
+  f->SetMinimumSize(5000); 
+  f->SetReplaceValue(1);
+  f->SetMultiplier(GetMultiplierForTrachea());
+  f->SetThresholdStepSize(GetThresholdStepSizeForTrachea());
+  f->SetMinimumThresholdStepSize(1);
+  f->VerboseOn();
+  for(unsigned int i=0; i<m_Seeds.size();i++) {
+    f->AddSeed(m_Seeds[i]);
+    // DD(m_Seeds[i]);
+  }  
+  f->Update();
+
+  writeImage<InternalImageType>(f->GetOutput(), "trg.mhd");
+
+  // take first (main) connected component
+  trachea_tmp = Labelize<InternalImageType>(f->GetOutput(), 
+                                           GetBackgroundValue(), 
+                                           true, 
+                                           GetMinimalComponentSize());
+  trachea_tmp = KeepLabels<InternalImageType>(trachea_tmp, 
+                                             GetBackgroundValue(), 
+                                             GetForegroundValue(), 
+                                             1, 1, false);
+}
+//--------------------------------------------------------------------
+
+
+//--------------------------------------------------------------------
+template <class ImageType>
+double 
+clitk::ExtractLungFilter<ImageType>::
+ComputeTracheaVolume()
+{
+  typedef itk::ImageRegionConstIterator<InternalImageType> IteratorType;
+  IteratorType iter(trachea_tmp, trachea_tmp->GetLargestPossibleRegion());
+  iter.GoToBegin();
+  double volume = 0.0;
+  while (!iter.IsAtEnd()) {
+    if (iter.Get() == this->GetForegroundValue()) volume++;
+    ++iter;
+  }
   
-  // If everything goes well, set the output
-  this->GraftOutput(output); // not SetNthOutput
+  double voxelsize = trachea_tmp->GetSpacing()[0]*trachea_tmp->GetSpacing()[1]*trachea_tmp->GetSpacing()[2];
+  return volume*voxelsize;
 }
 //--------------------------------------------------------------------
 
 
 //--------------------------------------------------------------------
-template <class ImageType, class MaskImageType>
+template <class ImageType>
 void 
-clitk::ExtractLungFilter<ImageType, MaskImageType>::
-TrackFromThisIndex(std::vector<BifurcationType> & listOfBifurcations, 
-                   MaskImagePointer skeleton, 
-                   MaskImageIndexType index,
-                   MaskImagePixelType label) {
-  DD("TrackFromThisIndex");
-  DD(index);
-  DD((int)label);
-  // Create NeighborhoodIterator 
-  typedef itk::NeighborhoodIterator<MaskImageType> NeighborhoodIteratorType;
-  typename NeighborhoodIteratorType::SizeType radius;
-  radius.Fill(1);
-  NeighborhoodIteratorType nit(radius, skeleton, skeleton->GetLargestPossibleRegion());
-      
-  // Track
-  std::vector<typename NeighborhoodIteratorType::IndexType> listOfTrackedPoint;
+clitk::ExtractLungFilter<ImageType>::
+SearchForTrachea()
+{
+  // Search for seed among n slices, skip some slices before starting
+  // if not found -> skip more and restart 
+  
+  // when seed found : perform region growing
+  // compute trachea volume
+  // if volume not plausible  -> skip more slices and restart 
+
   bool stop = false;
+  double volume = 0.0;
+  int skip = GetNumberOfSlicesToSkipBeforeSearchingSeed();
   while (!stop) {
-    nit.SetLocation(index);
-    // DD((int)nit.GetCenterPixel());
-    nit.SetCenterPixel(label);
-    listOfTrackedPoint.clear();
-    for(unsigned int i=0; i<nit.Size(); i++) {
-      if (i != nit.GetCenterNeighborhoodIndex ()) { // Do not observe the current point
-        //          DD(nit.GetIndex(i));
-        if (nit.GetPixel(i) == GetForegroundValue()) { // if this is foreground, we continue the tracking
-          // DD(nit.GetIndex(i));
-          listOfTrackedPoint.push_back(nit.GetIndex(i));
-        }
-      }
-    }
-    // DD(listOfTrackedPoint.size());
-    if (listOfTrackedPoint.size() == 1) {
-      index = listOfTrackedPoint[0];
-    }
-    else {
-      if (listOfTrackedPoint.size() == 2) {
-        BifurcationType bif(index, label, label+1, label+2);
-        listOfBifurcations.push_back(bif);
-        TrackFromThisIndex(listOfBifurcations, skeleton, listOfTrackedPoint[0], label+1);
-        TrackFromThisIndex(listOfBifurcations, skeleton, listOfTrackedPoint[1], label+2);
+    stop = SearchForTracheaSeed(skip);
+    if (stop) {
+      TracheaRegionGrowing();
+      volume = ComputeTracheaVolume()/1000; // assume mm3, so divide by 1000 to get cc
+      if ((volume > 10) && (volume < 55 )) { // it is ok
+        // Typical volume 22.59 cm 3 (± 7.69 cm 3 ) [ Leader 2004 ]
+       if (GetVerboseStep()) {
+         std::cout << "\t Found trachea with volume " << volume << " cc." << std::endl;
+       }
+        stop = true; 
       }
       else {
-        if (listOfTrackedPoint.size() > 2) {
-          std::cerr << "too much bifurcation points ... ?" << std::endl;
-          exit(0);
-        }
-        // Else this it the end of the tracking
+       if (GetVerboseStep()) {
+         std::cout << "\t The volume of the trachea (" << volume 
+                   << " cc) seems not correct. I skip some slices (" << skip << ") and restart to find seeds." 
+                   << std::endl;
+       }
+        skip += 5;
+        stop = false;
+       // empty the list of seed
+       m_Seeds.clear();
       }
-      stop = true;
     }
   }
+
+  if (volume != 0.0) {
+    // Set output
+    StopCurrentStep<InternalImageType>(trachea_tmp);
+  }
+  else { // Trachea not found
+    this->SetWarning("* WARNING * No seed found for trachea.");
+    StopCurrentStep();
+  }
 }
 //--------------------------------------------------------------------
 
-  
 #endif //#define CLITKBOOLEANOPERATORLABELIMAGEFILTER_TXX