itkRecursiveGaussianImageFilter.h

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/*=========================================================================
 *
 *  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 itkRecursiveGaussianImageFilter_h
#define itkRecursiveGaussianImageFilter_h

#include "itkRecursiveSeparableImageFilter.h"

namespace itk
{
template< typename TInputImage, typename TOutputImage = TInputImage >
class ITK_TEMPLATE_EXPORT RecursiveGaussianImageFilter:
  public RecursiveSeparableImageFilter< TInputImage, TOutputImage >
{
public:
  ITK_DISALLOW_COPY_AND_ASSIGN(RecursiveGaussianImageFilter);

  using Self = RecursiveGaussianImageFilter;
  using Superclass = RecursiveSeparableImageFilter< TInputImage, TOutputImage >;
  using Pointer = SmartPointer< Self >;
  using ConstPointer = SmartPointer< const Self >;

  using RealType = typename Superclass::RealType;
  using ScalarRealType = typename Superclass::ScalarRealType;

  itkNewMacro(Self);

  itkTypeMacro(RecursiveGaussianImageFilter, RecursiveSeparableImageFilter);

  itkGetConstMacro(Sigma, ScalarRealType);
  itkSetMacro(Sigma, ScalarRealType);

  typedef  enum { ZeroOrder, FirstOrder, SecondOrder } OrderEnumType;

  using OutputImageType = TOutputImage;

  itkSetMacro(NormalizeAcrossScale, bool);
  itkGetConstMacro(NormalizeAcrossScale, bool);

  itkSetMacro(Order, OrderEnumType);
  itkGetConstMacro(Order, OrderEnumType);

  void SetZeroOrder();

  void SetFirstOrder();

  void SetSecondOrder();

protected:
  RecursiveGaussianImageFilter();
  ~RecursiveGaussianImageFilter() override = default;
  void PrintSelf(std::ostream & os, Indent indent) const override;

  void SetUp(ScalarRealType spacing) override;

  /* See superclass for doxygen. This method adds the additional check
   * that sigma is greater than zero. */
  void VerifyPreconditions() ITKv5_CONST override;

private:
  void ComputeNCoefficients(ScalarRealType sigmad,
                            ScalarRealType A1, ScalarRealType B1, ScalarRealType W1, ScalarRealType L1,
                            ScalarRealType A2, ScalarRealType B2, ScalarRealType W2, ScalarRealType L2,
                            ScalarRealType & N0, ScalarRealType & N1,
                            ScalarRealType & N2, ScalarRealType & N3,
                            ScalarRealType & SN, ScalarRealType & DN, ScalarRealType & EN);

  void ComputeDCoefficients(ScalarRealType sigmad,
                            ScalarRealType W1, ScalarRealType L1, ScalarRealType W2, ScalarRealType L2,
                            ScalarRealType & SD, ScalarRealType & DD, ScalarRealType & ED);

  void ComputeRemainingCoefficients(bool symmetric);

  ScalarRealType m_Sigma;

  bool m_NormalizeAcrossScale;

  OrderEnumType m_Order;
};
} // end namespace itk

#ifndef ITK_MANUAL_INSTANTIATION
#include "itkRecursiveGaussianImageFilter.hxx"
#endif

#endif