itkScalarConnectedComponentImageFilter.h

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/*=========================================================================
 *
 *  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
 *
 *         https://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.
 *
 *=========================================================================*/
/*=========================================================================
 *
 *  Portions of this file are subject to the VTK Toolkit Version 3 copyright.
 *
 *  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
 *
 *  For complete copyright, license and disclaimer of warranty information
 *  please refer to the NOTICE file at the top of the ITK source tree.
 *
 *=========================================================================*/
#ifndef itkScalarConnectedComponentImageFilter_h
#define itkScalarConnectedComponentImageFilter_h
 
#include "itkMath.h"
#include "itkNumericTraits.h"
#include "itkConnectedComponentFunctorImageFilter.h"
 
namespace itk
{
 
namespace Functor
{
template <typename TInput>
class SimilarPixelsFunctor
{
public:
  SimilarPixelsFunctor()
    : m_Threshold(TInput{})
  {}
 
  ~SimilarPixelsFunctor() = default;
 
  bool
  operator==(const SimilarPixelsFunctor & other) const
  {
    return m_Threshold == other.m_Threshold;
  }
 
  ITK_UNEQUAL_OPERATOR_MEMBER_FUNCTION(SimilarPixelsFunctor);
 
  void
  SetDistanceThreshold(const TInput & thresh)
  {
    m_Threshold = thresh;
  }
 
  TInput
  GetDistanceThreshold()
  {
    return (m_Threshold);
  }
 
  bool
  operator()(const TInput & a, const TInput & b) const
  {
    using InputRealType = typename NumericTraits<TInput>::RealType;
    auto absDifference =
      static_cast<TInput>(itk::Math::abs(static_cast<InputRealType>(a) - static_cast<InputRealType>(b)));
    if (absDifference <= m_Threshold)
    {
      return true;
    }
 
    return false;
  }
 
protected:
  TInput m_Threshold;
};
} // end namespace Functor
 
template <typename TInputImage, typename TOutputImage, typename TMaskImage = TInputImage>
class ScalarConnectedComponentImageFilter
  : public ConnectedComponentFunctorImageFilter<TInputImage,
                                                TOutputImage,
                                                Functor::SimilarPixelsFunctor<typename TInputImage::ValueType>,
                                                TMaskImage>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(ScalarConnectedComponentImageFilter);

  using Self = ScalarConnectedComponentImageFilter;
  using Superclass =
    ConnectedComponentFunctorImageFilter<TInputImage,
                                         TOutputImage,
                                         Functor::SimilarPixelsFunctor<typename TInputImage::ValueType>,
                                         TMaskImage>;
 
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;

  itkNewMacro(Self);

  itkOverrideGetNameOfClassMacro(ScalarConnectedComponentImageFilter);
 
  using InputPixelType = typename TInputImage::PixelType;
 
  virtual void
  SetDistanceThreshold(const InputPixelType & thresh)
  {
    this->GetFunctor().SetDistanceThreshold(thresh);
  }
 
  virtual InputPixelType
  GetDistanceThreshold()
  {
    return (this->GetFunctor().GetDistanceThreshold());
  }
 
  itkConceptMacro(InputEqualityComparableCheck, (Concept::EqualityComparable<InputPixelType>));
  itkConceptMacro(OutputEqualityComparableCheck, (Concept::EqualityComparable<typename TOutputImage::PixelType>));
  itkConceptMacro(MaskEqualityComparableCheck, (Concept::EqualityComparable<typename TMaskImage::PixelType>));
  itkConceptMacro(OutputIncrementDecrementOperatorsCheck,
                  (Concept::IncrementDecrementOperators<typename TOutputImage::PixelType>));
 
protected:
  ScalarConnectedComponentImageFilter() = default;
  ~ScalarConnectedComponentImageFilter() override = default;
};
} // end namespace itk
 
#endif