text: /*=========================================================================
   *
   *  Copyright NumFOCUS
   *
   *  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 itkHausdorffDistanceImageFilter_h
  #define itkHausdorffDistanceImageFilter_h
  
  #include "itkImageToImageFilter.h"
  #include "itkNumericTraits.h"
  
  namespace itk
  {
  /**
   *\class HausdorffDistanceImageFilter
   * \brief Computes the Hausdorff distance between the set of
   * non-zero pixels of two images.
   *
   *
   * HausdorffDistanceImageFilter computes the distance between the set
   * non-zero pixels of two images using the following formula:
   * \f[ H(A,B) = \max(h(A,B),h(B,A)) \f]
   * where
   * \f[ h(A,B) = \max_{a \in A} \min_{b \in B} \| a - b\| \f] is the directed
   * Hausdorff distance
   * and \f$A\f$ and \f$B\f$ are respectively the set of non-zero pixels
   * in the first and second input images.
   *
   * In particular, this filter uses the DirectedHausdorffImageFilter inside to
   * compute the two directed distances and then select the largest of the two.
   *
   * The Hausdorff distance measures the degree of mismatch between two sets and
   * behaves like a metric over the set of all closed bounded sets -
   * with properties of identity, symmetry and triangle inequality.
   *
   * This filter requires the largest possible region of the first image
   * and the same corresponding region in the second image.
   * It behaves as filter with two inputs and one output. Thus it can be
   * inserted in a pipeline with other filters. The filter passes the first
   * input through unmodified.
   *
   * This filter is templated over the two input image types. It assume
   * both images have the same number of dimensions.
   *
   * \sa DirectedHausdorffDistanceImageFilter
   *
   * \ingroup MultiThreaded
   * \ingroup ITKDistanceMap
   */
  template <typename TInputImage1, typename TInputImage2>
  class ITK_TEMPLATE_EXPORT HausdorffDistanceImageFilter : public ImageToImageFilter<TInputImage1, TInputImage1>
  {
  public:
    ITK_DISALLOW_COPY_AND_MOVE(HausdorffDistanceImageFilter);
  
    /** Standard Self type alias */
    using Self = HausdorffDistanceImageFilter;
    using Superclass = ImageToImageFilter<TInputImage1, TInputImage1>;
    using Pointer = SmartPointer<Self>;
    using ConstPointer = SmartPointer<const Self>;
  
    /** Method for creation through the object factory. */
    itkNewMacro(Self);
  
    /** Runtime information support. */
    itkTypeMacro(HausdorffDistanceImageFilter, ImageToImageFilter);
  
    /** Image related type alias. */
    using InputImage1Type = TInputImage1;
    using InputImage2Type = TInputImage2;
    using InputImage1Pointer = typename TInputImage1::Pointer;
    using InputImage2Pointer = typename TInputImage2::Pointer;
    using InputImage1ConstPointer = typename TInputImage1::ConstPointer;
    using InputImage2ConstPointer = typename TInputImage2::ConstPointer;
  
    using RegionType = typename TInputImage1::RegionType;
    using SizeType = typename TInputImage1::SizeType;
    using IndexType = typename TInputImage1::IndexType;
  
    using InputImage1PixelType = typename TInputImage1::PixelType;
    using InputImage2PixelType = typename TInputImage2::PixelType;
  
    /** Image related type alias. */
    static constexpr unsigned int ImageDimension = TInputImage1::ImageDimension;
  
    /** Type to use form computations. */
    using RealType = typename NumericTraits<InputImage1PixelType>::RealType;
  
    /** Set the first input. */
    void
    SetInput1(const InputImage1Type * image);
  
    /** Set the second input. */
    void
    SetInput2(const InputImage2Type * image);
  
    /** Get the first input. */
    const InputImage1Type *
    GetInput1();
  
    /** Get the second input. */
    const InputImage2Type *
    GetInput2();
  
    /** Set if image spacing should be used in computing distances. */
    itkSetMacro(UseImageSpacing, bool);
    itkGetConstMacro(UseImageSpacing, bool);
  
    /** Return the computed Hausdorff distance. */
    itkGetConstMacro(HausdorffDistance, RealType);
    itkGetConstMacro(AverageHausdorffDistance, RealType);
  
  #ifdef ITK_USE_CONCEPT_CHECKING
    // Begin concept checking
    itkConceptMacro(Input1HasNumericTraitsCheck, (Concept::HasNumericTraits<InputImage1PixelType>));
    // End concept checking
  #endif
  
  protected:
    HausdorffDistanceImageFilter();
    ~HausdorffDistanceImageFilter() override = default;
    void
    PrintSelf(std::ostream & os, Indent indent) const override;
  
    /** GenerateData. */
    void
    GenerateData() override;
  
    // Override since the filter needs all the data for the algorithm
    void
    GenerateInputRequestedRegion() override;
  
    // Override since the filter produces all of its output
    void
    EnlargeOutputRequestedRegion(DataObject * data) override;
  
  private:
    RealType m_HausdorffDistance;
    RealType m_AverageHausdorffDistance;
    bool     m_UseImageSpacing;
  }; // end of class
  } // end namespace itk
  
  #ifndef ITK_MANUAL_INSTANTIATION
  #  include "itkHausdorffDistanceImageFilter.hxx"
  #endif
  
  #endif
  