itkGradientVectorFlowImageFilter.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.
 *
 *=========================================================================*/
#ifndef itkGradientVectorFlowImageFilter_h
#define itkGradientVectorFlowImageFilter_h
 
#include "vnl/vnl_matrix_fixed.h"
#include "itkMath.h"
#include "itkImage.h"
#include "itkVector.h"
#include "itkLaplacianImageFilter.h"
#include "itkImageRegionIterator.h"
 
namespace itk
{
template <typename TInputImage, typename TOutputImage, typename TInternalPixel = double>
class ITK_TEMPLATE_EXPORT GradientVectorFlowImageFilter : public ImageToImageFilter<TInputImage, TOutputImage>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(GradientVectorFlowImageFilter);

  using Self = GradientVectorFlowImageFilter;

  using Superclass = ImageToImageFilter<TInputImage, TOutputImage>;

  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;

  itkNewMacro(Self);

  itkOverrideGetNameOfClassMacro(GradientVectorFlowImageFilter);

  using InputImageType = TInputImage;
  using OutputImageType = TOutputImage;
 
  using IndexType = typename TInputImage::IndexType;
  using SizeType = typename TInputImage::SizeType;
  using PixelType = typename TInputImage::PixelType;
  using OutputImagePointer = typename OutputImageType::Pointer;
  using RegionType = typename OutputImageType::RegionType;

  using InputImageIterator = ImageRegionIterator<InputImageType>;
  using InputImageConstIterator = ImageRegionConstIterator<InputImageType>;
  using OutputImageIterator = ImageRegionIterator<OutputImageType>;

  static constexpr unsigned int ImageDimension = TInputImage::ImageDimension;
  static constexpr unsigned int OutputImageDimension = TOutputImage::ImageDimension;
 
  using InternalPixelType = TInternalPixel;
  using InternalImageType = itk::Image<InternalPixelType, Self::ImageDimension>;
  using InternalImagePointer = typename InternalImageType::Pointer;
  using InternalImageIterator = ImageRegionIterator<InternalImageType>;
  using InternalImageConstIterator = ImageRegionConstIterator<InternalImageType>;
 
  using LaplacianFilterType = LaplacianImageFilter<InternalImageType, InternalImageType>;
  using LaplacianFilterPointer = typename LaplacianFilterType::Pointer;

 
  itkSetObjectMacro(LaplacianFilter, LaplacianFilterType);
  itkGetModifiableObjectMacro(LaplacianFilter, LaplacianFilterType);
 
  itkSetMacro(TimeStep, double);
  itkGetConstMacro(TimeStep, double);
 
  itkSetMacro(NoiseLevel, double);
  itkGetConstMacro(NoiseLevel, double);
 
  itkSetMacro(IterationNum, int);
  itkGetConstMacro(IterationNum, int);
 
  itkConceptMacro(SameDimensionCheck, (Concept::SameDimension<ImageDimension, OutputImageDimension>));
  itkConceptMacro(InputHasNumericTraitsCheck, (Concept::HasNumericTraits<typename PixelType::ValueType>));
  itkConceptMacro(OutputHasNumericTraitsCheck,
                  (Concept::HasNumericTraits<typename TOutputImage::PixelType::ValueType>));
 
protected:
  GradientVectorFlowImageFilter();
  ~GradientVectorFlowImageFilter() override = default;
  void
  PrintSelf(std::ostream & os, Indent indent) const override;
 
  void
  GenerateData() override;

  void
  InitInterImage();

  void
  UpdateInterImage();

  void
  UpdatePixels();
 
private:
  // parameters;
  double m_TimeStep{};                               // the timestep of each
                                                     // iteration
  double m_Steps[Superclass::InputImageDimension]{}; // set to be 1 in all
                                                     // directions in most cases
  double m_NoiseLevel{};                             // the noise level of the
                                                     // image
  int m_IterationNum{};                              // the iteration number
 
  LaplacianFilterPointer                 m_LaplacianFilter{};
  typename Superclass::InputImagePointer m_IntermediateImage{};
 
  InternalImagePointer m_InternalImages[Superclass::InputImageDimension]{};
  InternalImagePointer m_BImage{}; // store the "b" value for every pixel
 
  typename Superclass::InputImagePointer m_CImage{}; // store the $c_i$ value for
                                                     // every pixel
};
} // end namespace itk
 
#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkGradientVectorFlowImageFilter.hxx"
#endif
 
#endif