Method ProcessColumn

Filters/General/vtkEqualizerFilter.cxx:359–450

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//------------------------------------------------------------------------------
void vtkEqualizerFilter::ProcessColumn(
  vtkDataArray* array, vtkTable* spectrumTable, vtkTable* resultTable, vtkTable* normalizedTable)
{
  // FFT
  auto spectrum = this->Internal->GetSpectrum(array);
  if (spectrum.empty())
  {
    vtkErrorMacro(<< "Spectrum is empty: " << array->GetName());
    return;
  }

  std::vector<double> normSpectrum = this->Internal->GetNormalizedSpectrum(array);
  if (normSpectrum.empty())
  {
    vtkErrorMacro(<< "Normalized spectrum is empty: " << array->GetName());
    return;
  }
  // end FFT

  // modify by equalizer
  auto modifiers = this->Internal->GetModifiers(this->SamplingFrequency);
  for (const auto& modifier : modifiers)
  {
    spectrum[modifier.first].r *= modifier.second;
    spectrum[modifier.first].i *= modifier.second;
    spectrum[this->Internal->SpectrumSize - modifier.first - 1].r *= modifier.second;
    spectrum[this->Internal->SpectrumSize - modifier.first - 1].i *= modifier.second;

    normSpectrum[modifier.first] *= modifier.second;
  }

  // fill spectrum table
  std::vector<double> freqArray =
    vtkFFT::RFftFreq(this->Internal->SpectrumSize, 1.0 / this->SamplingFrequency);

  vtkSmartPointer<vtkDoubleArray> freqColumn = vtkSmartPointer<vtkDoubleArray>::New();
  freqColumn->SetNumberOfComponents(1);
  freqColumn->SetNumberOfTuples(this->Internal->GetHalfSpectrumSize());
  freqColumn->SetName("Frequency");
  for (vtkIdType spectrumId = 0; spectrumId < this->Internal->GetHalfSpectrumSize(); ++spectrumId)
  {
    freqColumn->SetValue(spectrumId, freqArray.at(spectrumId));
  }

  spectrumTable->AddColumn(freqColumn);
  normalizedTable->AddColumn(freqColumn);

  vtkSmartPointer<vtkDoubleArray> leadArray = vtkSmartPointer<vtkDoubleArray>::New();
  leadArray->SetNumberOfComponents(1);
  leadArray->SetNumberOfTuples(this->Internal->GetHalfSpectrumSize());
  leadArray->SetName(array->GetName());

  vtkSmartPointer<vtkDoubleArray> normalizedArray = vtkSmartPointer<vtkDoubleArray>::New();
  normalizedArray->SetNumberOfComponents(1);
  normalizedArray->SetNumberOfTuples(this->Internal->GetHalfSpectrumSize());
  normalizedArray->SetName(array->GetName());

  double modifier = pow(10, 0.05 * this->SpectrumGain);