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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 itkChainCodeToFourierSeriesPathFilter_hxx
#define itkChainCodeToFourierSeriesPathFilter_hxx
#include <cmath>
namespace itk
{
template <typename TInputChainCodePath, typename TOutputFourierSeriesPath>
ChainCodeToFourierSeriesPathFilter<TInputChainCodePath, TOutputFourierSeriesPath>::ChainCodeToFourierSeriesPathFilter()
{
this->SetNumberOfRequiredInputs(1);
m_NumberOfHarmonics = 8;
}
template <typename TInputChainCodePath, typename TOutputFourierSeriesPath>
void
ChainCodeToFourierSeriesPathFilter<TInputChainCodePath, TOutputFourierSeriesPath>::GenerateData()
{
IndexType index;
VectorType indexVector;
VectorType cosCoefficient;
VectorType sinCoefficient;
OutputPathInputType theta;
size_t numSteps;
unsigned int numHarmonics = m_NumberOfHarmonics; // private copy
int dimension = OffsetType::GetOffsetDimension();
typename Superclass::InputPathConstPointer inputPtr = this->GetInput();
typename Superclass::OutputPathPointer outputPtr = this->GetOutput(0);
// outputPtr->SetRequestedRegion( inputPtr->GetRequestedRegion() );
// outputPtr->SetBufferedRegion( inputPtr->GetBufferedRegion() );
// outputPtr->SetLargestPossibleRegion( inputPtr->GetLargestPossibleRegion() );
// outputPtr->Allocate(); // Allocate() is an Image function
numSteps = inputPtr->NumberOfSteps();
outputPtr->Clear();
const double nPI = 4.0 * std::atan(1.0);
// Adjust our private copy of numHarmonics if necessary
if (numHarmonics <= 1)
{
numHarmonics = 2;
}
else if (numHarmonics * 2 > numSteps)
{
numHarmonics = numSteps / 2;
}
for (unsigned int n = 0; n < numHarmonics; ++n)
{
index = inputPtr->GetStart();
cosCoefficient.Fill(0.0);
sinCoefficient.Fill(0.0);
for (InputPathInputType step = 0; step < numSteps; ++step)
{
index += inputPtr->Evaluate(step);
theta = 2 * n * nPI * (static_cast<double>(step + 1)) / numSteps;
// turn the current index into a vector
for (int d = 0; d < dimension; ++d)
{
indexVector[d] = index[d];
}
cosCoefficient += indexVector * (std::cos(theta) / numSteps);
sinCoefficient += indexVector * (std::sin(theta) / numSteps);
}
outputPtr->AddHarmonic(cosCoefficient, sinCoefficient);
}
}
template <typename TInputChainCodePath, typename TOutputFourierSeriesPath>
void
ChainCodeToFourierSeriesPathFilter<TInputChainCodePath, TOutputFourierSeriesPath>::PrintSelf(std::ostream & os,
Indent indent) const
{
Superclass::PrintSelf(os, indent);
os << indent << "NumberOfHarmonics: " << m_NumberOfHarmonics << std::endl;
}
} // end namespace itk
#endif
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