itkGaborKernelFunction.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 itkGaborKernelFunction_h
#define itkGaborKernelFunction_h
 
#include "itkKernelFunctionBase.h"
#include <cmath>
 
namespace itk
{
template <typename TRealValueType>
class ITK_TEMPLATE_EXPORT GaborKernelFunction : public KernelFunctionBase<TRealValueType>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(GaborKernelFunction);

  using Self = GaborKernelFunction;
  using Superclass = KernelFunctionBase<TRealValueType>;
  using Pointer = SmartPointer<Self>;

  itkNewMacro(Self);

  itkOverrideGetNameOfClassMacro(GaborKernelFunction);

  TRealValueType
  Evaluate(const TRealValueType & u) const override
  {
    TRealValueType parameter = itk::Math::sqr(u / this->m_Sigma);
    TRealValueType envelope = std::exp(TRealValueType{ -0.5 } * parameter);
    TRealValueType phase = TRealValueType{ 2.0 * itk::Math::pi } * this->m_Frequency * u + this->m_PhaseOffset;
 
    if (this->m_CalculateImaginaryPart)
    {
      return envelope * std::sin(phase);
    }
 
    return envelope * std::cos(phase);
  }

  itkSetMacro(Sigma, TRealValueType);
  itkGetConstMacro(Sigma, TRealValueType);
  itkSetMacro(Frequency, TRealValueType);
  itkGetConstMacro(Frequency, TRealValueType);
  itkSetMacro(PhaseOffset, TRealValueType);
  itkGetConstMacro(PhaseOffset, TRealValueType);
  itkSetMacro(CalculateImaginaryPart, bool);
  itkGetConstMacro(CalculateImaginaryPart, bool);
  itkBooleanMacro(CalculateImaginaryPart);
protected:
  GaborKernelFunction()
  {
    this->m_CalculateImaginaryPart = false;
    this->m_Sigma = TRealValueType{ 1.0 };
    this->m_Frequency = TRealValueType{ 0.4 };
    this->m_PhaseOffset = TRealValueType{ 0.0 };
  }
  ~GaborKernelFunction() override = default;
  void
  PrintSelf(std::ostream & os, Indent indent) const override
  {
    Superclass::PrintSelf(os, indent);
 
    os << indent << "Sigma: " << this->GetSigma() << std::endl;
    os << indent << "Frequency: " << this->GetFrequency() << std::endl;
    os << indent << "PhaseOffset: " << this->GetPhaseOffset() << std::endl;
    os << indent << "CalculateImaginaryPart: " << this->GetCalculateImaginaryPart() << std::endl;
  }
 
private:
  TRealValueType m_Sigma{};
 
  TRealValueType m_Frequency{};
 
  TRealValueType m_PhaseOffset{};
 
  bool m_CalculateImaginaryPart{};
};
} // end namespace itk
 
#endif