itkImageGaussianModelEstimator.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 itkImageGaussianModelEstimator_h
#define itkImageGaussianModelEstimator_h
 
#include <cmath>
#include <cfloat>
#include <memory> // For unique_ptr.
 
#include "vnl/vnl_vector.h"
#include "vnl/vnl_matrix.h"
#include "vnl/vnl_matrix_fixed.h"
#include "itkMath.h"
#include "vnl/algo/vnl_matrix_inverse.h"
 
#include "itkImageRegionIterator.h"
#include "itkMacro.h"
 
#include "itkImageModelEstimatorBase.h"
 
namespace itk
{
template <typename TInputImage, typename TMembershipFunction, typename TTrainingImage>
class ITK_TEMPLATE_EXPORT ImageGaussianModelEstimator : public ImageModelEstimatorBase<TInputImage, TMembershipFunction>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(ImageGaussianModelEstimator);

  using Self = ImageGaussianModelEstimator;
  using Superclass = ImageModelEstimatorBase<TInputImage, TMembershipFunction>;
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;

  itkNewMacro(Self);

  itkOverrideGetNameOfClassMacro(ImageGaussianModelEstimator);

  using InputImageType = TInputImage;
  using InputImagePointer = typename TInputImage::Pointer;
  using InputImageConstPointer = typename TInputImage::ConstPointer;

  using TrainingImageType = TTrainingImage;
  using TrainingImagePointer = typename TTrainingImage::Pointer;
  using TrainingImageConstPointer = typename TTrainingImage::ConstPointer;

  using InputImagePixelType = typename TInputImage::PixelType;

  using TrainingImagePixelType = typename TTrainingImage::PixelType;

  using InputImageIterator = ImageRegionIterator<TInputImage>;
  using InputImageConstIterator = ImageRegionConstIterator<TInputImage>;
  using TrainingImageIterator = ImageRegionIterator<TTrainingImage>;
  using TrainingImageConstIterator = ImageRegionConstIterator<TTrainingImage>;

  using MembershipFunctionType = TMembershipFunction;
  using MembershipFunctionPointer = typename TMembershipFunction::Pointer;

  itkSetObjectMacro(TrainingImage, TrainingImageType);
  itkGetModifiableObjectMacro(TrainingImage, TrainingImageType);
 
protected:
  ImageGaussianModelEstimator() = default;
  ~ImageGaussianModelEstimator() override = default;
  void
  PrintSelf(std::ostream & os, Indent indent) const override;

  void
  GenerateData() override;
 
private:
  using MatrixType = vnl_matrix<double>;
 
  using InputImageSizeType = typename TInputImage::SizeType;

  static constexpr unsigned int VectorDimension = InputImagePixelType::Dimension;

  void
  EstimateModels() override;
 
  void
  EstimateGaussianModelParameters();
 
  MatrixType                    m_NumberOfSamples{};
  MatrixType                    m_Means{};
  std::unique_ptr<MatrixType[]> m_Covariance{ nullptr };
 
  TrainingImagePointer m_TrainingImage{};
};
} // end namespace itk
 
#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkImageGaussianModelEstimator.hxx"
#endif
 
#endif