text: /*=========================================================================
   *
   *  Copyright Insight Software Consortium
   *
   *  Licensed under the Apache License, Version 2.0 (the "License");
   *  you may not use this file except in compliance with the License.
   *  You may obtain a copy of the License at
   *
   *         http://www.apache.org/licenses/LICENSE-2.0.txt
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   *
   *=========================================================================*/
  #ifndef __itkNarrowBandCurvesLevelSetImageFilter_h
  #define __itkNarrowBandCurvesLevelSetImageFilter_h
  
  #include "itkNarrowBandLevelSetImageFilter.h"
  #include "itkCurvesLevelSetFunction.h"
  
  namespace itk
  {
  /** \class NarrowBandCurvesLevelSetImageFilter
   *  \brief Segments structures in images based on user supplied edge potential map.
   *
   *   \par IMPORTANT
   *   The NarrowBandLevelSetImageFilter class and the
   *   CurvesLevelSetFunction class contain additional information necessary
   *   to the full understanding of how to use this filter.
   *
   *    \par OVERVIEW
   *    This class is a level set method segmentation filter. An initial contour
   *    is propagated outwards (or inwards) until it sticks to the shape boundaries.
   *    This is done by using a level set speed function based on a user supplied
   *    edge potential map.
   *
   *    \par INPUTS
   *    This filter requires two inputs.  The first input is a initial level set.
   *    The initial level set is a real image which contains the initial contour/surface
   *    as the zero level set. For example, a signed distance function from the initial
   *    contour/surface is typically used. Unlike the simpler ShapeDetectionLevelSetImageFilter
   *    the initial contour does not have to lie wholly within the shape to be segmented.
   *    The initial contour is allow to overlap the shape boundary. The extra advection term
   *    in the update equation behaves like a doublet and attracts the contour to the boundary.
   *    This approach for segmentation follows that of Lorigo et al (2001).
   *
   *    \par
   *    The second input is the feature image.  For this filter, this is the edge
   *    potential map. General characteristics of an edge potential map is that
   *    it has values close to zero in regions near the edges and values close
   *    to one inside the shape itself. Typically, the edge potential map is compute
   *    from the image gradient, for example:
   *
   *    \f[ g(I) = 1 / ( 1 + | (\nabla * G)(I)| ) \f]
   *    \f[ g(I) = \exp^{-|(\nabla * G)(I)|} \f]
   *
   *    where \f$ I \f$ is image intensity and
   *    \f$ (\nabla * G) \f$ is the derivative of Gaussian operator.
   *
   *    \par
   *    See NarrowBandLevelSetImageFilter and NarrowBandImageFilterBase
   *    for more information on Inputs.
   *
   *    \par PARAMETERS
   *    The method SetUseNegatiiveFeatures() can be used to switch from propagating inwards (false)
   *    versus propagting outwards (true).
   *
   *    This implementation allows the user to set the weights between the propagation, advection
   *    and curvature term using methods SetPropagationScaling(), SetAdvectionScaling(),
   *    SetCurvatureScaling(). In general, the larger the CurvatureScaling, the smoother the
   *    resulting contour. To follow the implementation in Caselles's paper,
   *    set the PropagationScaling to \f$ c \f$ (the inflation or ballon force) and
   *    AdvectionScaling and CurvatureScaling both to 1.0.
   *
   *    \par OUTPUTS
   *    The filter outputs a single, scalar, real-valued image.
   *    Negative values in the output image are inside the segmentated region
   *    and positive values in the image are outside of the inside region.  The
   *    zero crossings of the image correspond to the position of the level set
   *    front.
   *
   *    \par REFERENCES
   *    L. Lorigo, O. Faugeras, W.E.L. Grimson, R. Keriven, R. Kikinis, A. Nabavi,
   *    and C.-F. Westin, Curves: Curve evolution for vessel segmentation.
   *    Medical Image Analysis, 5:195-206, 2001.
   *
   *   \par
   *   See NarrowBandImageFilterBase and
   *   NarrowBandLevelSetImageFilter for more information.
   *
   *   \sa NarrowBandLevelSetImageFilter
   *   \sa CurvesLevelSetFunction
   *
   *   \ingroup LevelSetSegmentation
   * \ingroup ITKLevelSets
   */
  template< typename TInputImage,
            typename TFeatureImage,
            typename TOutputPixelType = float >
  class NarrowBandCurvesLevelSetImageFilter:
    public NarrowBandLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType,
                                          Image< TOutputPixelType,
                                                 TInputImage::ImageDimension > >
  {
  public:
    /** Standard class typedefs */
    typedef NarrowBandCurvesLevelSetImageFilter Self;
    typedef  NarrowBandLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType,
                                            Image< TOutputPixelType,
                                                   TInputImage::ImageDimension > >
    Superclass;
    typedef SmartPointer< Self >       Pointer;
    typedef SmartPointer< const Self > ConstPointer;
  
    /** Inherited typedef from the superclass. */
    typedef typename Superclass::ValueType        ValueType;
    typedef typename Superclass::OutputImageType  OutputImageType;
    typedef typename Superclass::FeatureImageType FeatureImageType;
  
    /** Type of the segmentation function */
    typedef CurvesLevelSetFunction< OutputImageType,
                                    FeatureImageType > CurvesFunctionType;
    typedef typename CurvesFunctionType::Pointer
    CurvesFunctionPointer;
  
    /** Run-time type information (and related methods). */
    itkTypeMacro(NarrowBandCurvesLevelSetImageFilter, NarrowBandLevelSetImageFilter);
  
    /** Method for creation through the object factory */
    itkNewMacro(Self);
  
    /** Set the value of sigma used to compute derivatives */
    void SetDerivativeSigma(float value)
    {
      m_CurvesFunction->SetDerivativeSigma(value);
      this->Modified();
    }
  
    float GetDerivativeSigma() const
    { return m_CurvesFunction->GetDerivativeSigma(); }
  
  #ifdef ITK_USE_CONCEPT_CHECKING
    // Begin concept checking
    itkConceptMacro( OutputHasNumericTraitsCheck,
                     ( Concept::HasNumericTraits< TOutputPixelType > ) );
    // End concept checking
  #endif
  
  protected:
    ~NarrowBandCurvesLevelSetImageFilter() {}
    NarrowBandCurvesLevelSetImageFilter();
  
    virtual void PrintSelf(std::ostream & os, Indent indent) const;
  
    NarrowBandCurvesLevelSetImageFilter(const Self &); // purposely not
                                                       // implemented
    void operator=(const Self &);                      //purposely not implemented
  
    /** Overridden from Superclass to handle the case when Propagation
     *  Scaling is zero.*/
    void GenerateData();
  
  private:
    CurvesFunctionPointer m_CurvesFunction;
  };
  } // end namespace itk
  
  #ifndef ITK_MANUAL_INSTANTIATION
  #include "itkNarrowBandCurvesLevelSetImageFilter.hxx"
  #endif
  
  #endif
  