itkExpectationMaximizationMixtureModelEstimator.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
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 *  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.
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 *=========================================================================*/
#ifndef __itkExpectationMaximizationMixtureModelEstimator_h
#define __itkExpectationMaximizationMixtureModelEstimator_h

#include "itkMixtureModelComponentBase.h"
#include "itkGaussianMembershipFunction.h"
#include "itkSimpleDataObjectDecorator.h"

namespace itk
{
namespace Statistics
{
template< typename TSample >
class ExpectationMaximizationMixtureModelEstimator:public Object
{
public:
  typedef ExpectationMaximizationMixtureModelEstimator Self;
  typedef Object                                       Superclass;
  typedef SmartPointer< Self >                         Pointer;
  typedef SmartPointer< const Self >                   ConstPointer;

  itkTypeMacro(ExpectationMaximizationMixtureModelEstimator,
               Object);
  itkNewMacro(Self);

  typedef TSample                                 SampleType;
  typedef typename TSample::MeasurementType       MeasurementType;
  typedef typename TSample::MeasurementVectorType MeasurementVectorType;

  typedef GaussianMembershipFunction< MeasurementVectorType >
  GaussianMembershipFunctionType;

  typedef typename GaussianMembershipFunctionType::Pointer
  GaussianMembershipFunctionPointer;

  typedef MembershipFunctionBase< MeasurementVectorType > MembershipFunctionType;
  typedef typename MembershipFunctionType::ConstPointer   MembershipFunctionPointer;
  typedef std::vector< MembershipFunctionPointer >        MembershipFunctionVectorType;
  typedef SimpleDataObjectDecorator<
    MembershipFunctionVectorType >                        MembershipFunctionVectorObjectType;
  typedef typename
  MembershipFunctionVectorObjectType::Pointer MembershipFunctionVectorObjectPointer;

  typedef MixtureModelComponentBase< TSample > ComponentType;

  typedef std::vector< ComponentType * > ComponentVectorType;

  typedef MembershipFunctionBase< MeasurementVectorType >
  ComponentMembershipFunctionType;

  typedef Array< double > ProportionVectorType;

  void SetSample(const TSample *sample);

  const TSample * GetSample() const;

  void SetInitialProportions(ProportionVectorType & propotion);

  const ProportionVectorType & GetInitialProportions() const;

  const ProportionVectorType & GetProportions() const;

  typedef SimpleDataObjectDecorator<
    ProportionVectorType >                 MembershipFunctionsWeightsArrayObjectType;
  typedef typename
  MembershipFunctionsWeightsArrayObjectType::Pointer MembershipFunctionsWeightsArrayPointer;

  const MembershipFunctionsWeightsArrayObjectType * GetMembershipFunctionsWeightsArray() const;

  void SetMaximumIteration(int numberOfIterations);

  int GetMaximumIteration() const;

  int GetCurrentIteration()
  {
    return m_CurrentIteration;
  }

  int AddComponent(ComponentType *component);

  unsigned int GetNumberOfComponents() const;

  void Update();

  enum TERMINATION_CODE { CONVERGED = 0, NOT_CONVERGED = 1 };

  TERMINATION_CODE GetTerminationCode() const;

  ComponentMembershipFunctionType * GetComponentMembershipFunction(int componentIndex) const;

  const MembershipFunctionVectorObjectType * GetOutput() const;

protected:
  ExpectationMaximizationMixtureModelEstimator();
  virtual ~ExpectationMaximizationMixtureModelEstimator() {}
  virtual void PrintSelf(std::ostream & os, Indent indent) const ITK_OVERRIDE;

  bool CalculateDensities();

  double CalculateExpectation() const;

  bool UpdateComponentParameters();

  bool UpdateProportions();

  void GenerateData();

private:
  const TSample *m_Sample;

  int m_MaxIteration;
  int m_CurrentIteration;

  TERMINATION_CODE     m_TerminationCode;
  ComponentVectorType  m_ComponentVector;
  ProportionVectorType m_InitialProportions;
  ProportionVectorType m_Proportions;

  MembershipFunctionVectorObjectPointer  m_MembershipFunctionsObject;
  MembershipFunctionsWeightsArrayPointer m_MembershipFunctionsWeightArrayObject;
};  // end of class
} // end of namespace Statistics
} // end of namespace itk

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

#endif