private void UpdateSpectra()
{
var fftSize = int.Parse(fftSizeTextBox.Text);
var cepstrumSize = int.Parse(cepstrumSizeTextBox.Text);
_hopSize = int.Parse(hopSizeTextBox.Text);
if (fftSize != _fftSize)
{
_fftSize = fftSize;
_fft = new Fft(fftSize);
_cepstralTransform = new CepstralTransform(cepstrumSize, _fftSize);
}
if (cepstrumSize != _cepstrumSize)
{
_cepstrumSize = cepstrumSize;
_cepstralTransform = new CepstralTransform(_cepstrumSize, _fftSize);
}
var pos = _hopSize * _specNo;
var block = _signal[pos, pos + _fftSize];
block.ApplyWindow(WindowTypes.Hamming);
var cepstrum = _cepstralTransform.Direct(block);
var real = new float[_fftSize];
var imag = new float[_fftSize];
for (var i = 0; i < 32; i++)
{
real[i] = cepstrum[i];
}
_fft.Direct(real, imag);
var spectrum = _fft.PowerSpectrum(block, normalize: false).Samples;
var avg = spectrum.Average(s => LevelScale.ToDecibel(s));
var spectrumEstimate = real.Take(_fftSize / 2 + 1)
.Select(s => (float)LevelScale.FromDecibel(s * 40 / _fftSize - avg))
.ToArray();
spectrumPanel.Line = spectrum;
spectrumPanel.Markline = spectrumEstimate;
spectrumPanel.ToDecibel();
var pitch = Pitch.AutoCorrelation(block);
cepstrumPanel.Line = cepstrum.Samples;
cepstrumPanel.Mark = (int)(_signal.SamplingRate / pitch);
}
private void UpdateAutoCorrelation()
{
var pos = _hopSize * _specNo;
var block = _signal[pos, pos + _fftSize];
var pitch = Pitch.AutoCorrelation(block);
spectrumPanel.Mark = (int)(_fftSize * pitch / _signal.SamplingRate); // pitch index
spectrumPanel.Legend = string.Format("{0:F2} Hz", pitch);
var autoCorrelation = Operation.CrossCorrelate(block, block).Last(_fftSize);
autoCorrPanel.Line = autoCorrelation.Samples;
autoCorrPanel.Mark = (int)(_signal.SamplingRate / _pitchTrack[_specNo]); // pitch index
}