itkGradientRecursiveGaussianImageFilter.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 itkGradientRecursiveGaussianImageFilter_h
#define itkGradientRecursiveGaussianImageFilter_h
 
#include "itkRecursiveGaussianImageFilter.h"
#include "itkNthElementImageAdaptor.h"
#include "itkImage.h"
#include "itkCovariantVector.h"
#include "itkDefaultConvertPixelTraits.h"
#include "itkProgressAccumulator.h"
#include "itkImageRegionIterator.h"
#include "itkVectorImage.h"
#include <vector>
 
namespace itk
{
template <
  typename TInputImage,
  typename TOutputImage = Image<
    CovariantVector<typename NumericTraits<typename TInputImage::PixelType>::RealType, TInputImage::ImageDimension>,
    TInputImage::ImageDimension>>
class ITK_TEMPLATE_EXPORT GradientRecursiveGaussianImageFilter : public ImageToImageFilter<TInputImage, TOutputImage>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(GradientRecursiveGaussianImageFilter);

  using Self = GradientRecursiveGaussianImageFilter;
  using Superclass = ImageToImageFilter<TInputImage, TOutputImage>;
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;

  using InputImageType = TInputImage;
  using PixelType = typename TInputImage::PixelType;
  using RealType = typename NumericTraits<PixelType>::RealType;
  using ScalarRealType = typename NumericTraits<PixelType>::ScalarRealType;

  using InternalRealType = typename NumericTraits<RealType>::FloatType;
  using InternalScalarRealType = typename NumericTraits<InternalRealType>::ValueType;

  static constexpr unsigned int ImageDimension = TInputImage::ImageDimension;

  using GradientVectorType = CovariantVector<ScalarRealType, ImageDimension>;

  using RealImageType = Image<InternalRealType, Self::ImageDimension>;
 

  using OutputImageAdaptorType = NthElementImageAdaptor<TOutputImage, InternalScalarRealType>;
 
  using OutputImageAdaptorPointer = typename OutputImageAdaptorType::Pointer;

  using SigmaArrayType = FixedArray<ScalarRealType, Self::ImageDimension>;

  using GaussianFilterType = RecursiveGaussianImageFilter<RealImageType, RealImageType>;

  using DerivativeFilterType = RecursiveGaussianImageFilter<InputImageType, RealImageType>;

  using GaussianFilterPointer = typename GaussianFilterType::Pointer;

  using DerivativeFilterPointer = typename DerivativeFilterType::Pointer;

  using OutputImagePointer = typename TOutputImage::Pointer;

  using OutputImageType = TOutputImage;
  using OutputPixelType = typename OutputImageType::PixelType;
  using OutputComponentType = typename NumericTraits<OutputPixelType>::ValueType;
  using CovariantVectorType = CovariantVector<OutputComponentType, ImageDimension>;

  itkNewMacro(Self);

  itkOverrideGetNameOfClassMacro(GradientRecursiveGaussianImageFilter);

  void
  SetSigmaArray(const SigmaArrayType & sigma);
  void
  SetSigma(ScalarRealType sigma);
 
  SigmaArrayType
  GetSigmaArray() const;

  ScalarRealType
  GetSigma() const;

  void
  SetNormalizeAcrossScale(bool normalize);
  itkGetConstMacro(NormalizeAcrossScale, bool);

  void
  GenerateInputRequestedRegion() override;

  itkSetMacro(UseImageDirection, bool);
  itkGetConstMacro(UseImageDirection, bool);
  itkBooleanMacro(UseImageDirection);
 
  // Does not seem to work with wrappings, disabled
  // itkConceptMacro( InputHasNumericTraitsCheck,
  //                 ( Concept::HasNumericTraits< PixelType > ) );
 
protected:
  GradientRecursiveGaussianImageFilter();
  ~GradientRecursiveGaussianImageFilter() override = default;
  void
  PrintSelf(std::ostream & os, Indent indent) const override;

  void
  GenerateData() override;
 
  // Override since the filter produces the entire dataset
  void
  EnlargeOutputRequestedRegion(DataObject * output) override;
 
  void
  GenerateOutputInformation() override;
 
private:
  template <typename TValue>
  void
  TransformOutputPixel(ImageRegionIterator<VectorImage<TValue, ImageDimension>> & it)
  {
    // To transform Variable length vector we need to convert to and
    // from the CovariantVectorType
    const CovariantVectorType gradient(it.Get().GetDataPointer());
    CovariantVectorType       physicalGradient;
    it.GetImage()->TransformLocalVectorToPhysicalVector(gradient, physicalGradient);
    it.Set(OutputPixelType(physicalGradient.GetDataPointer(), ImageDimension, false));
  }
 
  template <typename T>
  void
  TransformOutputPixel(ImageRegionIterator<T> & it)
  {
    OutputPixelType         correctedGradient{};
    const OutputPixelType & gradient = it.Get();
 
    const unsigned int nComponents = NumericTraits<OutputPixelType>::GetLength(gradient) / ImageDimension;
 
    for (unsigned int nc = 0; nc < nComponents; ++nc)
    {
      GradientVectorType componentGradient;
      GradientVectorType correctedComponentGradient;
      for (unsigned int dim = 0; dim < ImageDimension; ++dim)
      {
        componentGradient[dim] =
          DefaultConvertPixelTraits<OutputPixelType>::GetNthComponent(nc * ImageDimension + dim, gradient);
      }
      it.GetImage()->TransformLocalVectorToPhysicalVector(componentGradient, correctedComponentGradient);
      for (unsigned int dim = 0; dim < ImageDimension; ++dim)
      {
        DefaultConvertPixelTraits<OutputPixelType>::SetNthComponent(
          nc * ImageDimension + dim, correctedGradient, correctedComponentGradient[dim]);
      }
    }
    it.Set(correctedGradient);
  }
 
  template <template <typename, unsigned int> class P, class T, unsigned int VDimension>
  void
  TransformOutputPixel(ImageRegionIterator<Image<P<T, VDimension>, VDimension>> & it)
  {
    const OutputPixelType gradient = it.Get();
    // This uses the more efficient set by reference method
    it.GetImage()->TransformLocalVectorToPhysicalVector(gradient, it.Value());
  }
 
 
  std::vector<GaussianFilterPointer> m_SmoothingFilters{};
  DerivativeFilterPointer            m_DerivativeFilter{};
  OutputImageAdaptorPointer          m_ImageAdaptor{};

  bool m_NormalizeAcrossScale{};

  bool m_UseImageDirection{ true };

  SigmaArrayType m_Sigma{};
};
} // end namespace itk
 
#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkGradientRecursiveGaussianImageFilter.hxx"
#endif
 
#endif