public double[] SynthetizeNoise(Bitmap image, int samplerate)
{
using (new DebugTimer("Spectrogram: SynthetizeNoise()"))
{
int samples = (int)image.Width * samplerate / pixpersec;
Complex[] noise = SpectrogramUtils.GetPinkNoise(samplerate * 10); // 10 sec loop
double filterscale = ((double)noise.Length * 2) / samplerate;
Filterbank filterbank = Filterbank.GetFilterbank(frequency_axis, filterscale, basefreq, bandwidth, overlap);
int top_index = (int)(maxfreq * filterscale);
var @out = new double[samples];
for (int bandidx = 0; bandidx < image.Height; ++bandidx)
{
//if (cancelled())
// return List<int>();
OutputBandProgress(bandidx, image.Height - 1);
// filter noise
Pair <int, int> range = filterbank.GetBand(bandidx);
//std::cout << bandidx << "/"<<image.height()<<"\n";
Console.Out.WriteLine("(noise) sample: {0}", range.Second - range.First);
var filtered_noise = new Complex[noise.Length];
// TODO: copy noise into filtered_noise array
//std.copy(noise.begin()+range.first, noise.begin()+Math.Min(range.second, top_index), filtered_noise.begin()+range.first);
//apply_window(filtered_noise, range.first, filterscale);
// ifft noise
double[] noise_mod = SpectrogramUtils.padded_IFFT(ref filtered_noise);
// resample spectrogram band
double[] envelope = SpectrogramUtils.Resample(EnvelopeFromSpectrogram(image, bandidx), samples);
// modulate with looped noise
for (uint i = 0; i < samples; ++i)
{
@out[i] += envelope[i] * noise_mod[i % noise_mod.Length];
}
}
SpectrogramUtils.NormalizeSignal(ref @out);
return(@out);
}
}
public double[] SynthetizeSine(Bitmap image, int samplerate)
{
using (new DebugTimer("Spectrogram: SynthetizeSine(Bitmap)"))
{
int samples = image.Width * samplerate / pixpersec;
var spectrum = new Complex[samples / 2 + 1];
double filterscale = ((double)spectrum.Length * 2) / samplerate;
Filterbank filterbank = Filterbank.GetFilterbank(frequency_axis, filterscale, basefreq, bandwidth, overlap);
for (int bandidx = 0; bandidx < image.Height; ++bandidx)
{
// TODO: support cancelling this process
OutputBandProgress(bandidx, image.Height);
double[] envelope = EnvelopeFromSpectrogram(image, bandidx);
// Find maximum number when all numbers are made positive.
//double max = envelope.Max((b) => Math.Abs(b));
//Console.WriteLine(max);
// random phase between +-pi
double phase = SpectrogramUtils.RandomDoubleMinus1ToPlus1() * Math.PI;
var bandsignal = new double[envelope.Length * 2];
for (int j = 0; j < 4; ++j)
{
double sine = Math.Cos(j * Math.PI / 2 + phase);
for (int i = j; i < bandsignal.Length; i += 4)
{
bandsignal[i] = envelope[i / 2] * sine;
}
}
var filterband = SpectrogramUtils.padded_FFT(ref bandsignal);
for (int i = 0; i < filterband.Length; ++i)
{
double x = (double)i / filterband.Length;
// normalized blackman window antiderivative
filterband[i] *= x - ((0.5 / (2.0 * Math.PI)) * Math.Sin(2.0 * Math.PI * x) + (0.08 / (4.0 * Math.PI)) * Math.Sin(4.0 * Math.PI * x) / 0.42);
}
//Console.Out.WriteLine("Spectrum size: {0}", spectrum.Length);
//std::cout << bandidx << ". filterband size: " << filterband.Length << "; start: " << filterbank->GetBand(bandidx).first <<"; end: " << filterbank->GetBand(bandidx).second << "\n";
double center = filterbank.GetCenter(bandidx);
double offset = Math.Max((double)0, center - filterband.Length / 2);
//Console.Out.WriteLine("Offset: {0} = {1} hz", offset, offset/filterscale);
for (int i = 0; i < filterband.Length; ++i)
{
int spectrumIndex = (int)(offset + i);
if (spectrumIndex > 0 && spectrumIndex < spectrum.Length)
{
spectrum[spectrumIndex] += filterband[i];
}
}
}
double[] @out = SpectrogramUtils.padded_IFFT(ref spectrum);
Console.Out.WriteLine("Samples: {0} -> {1}", @out.Length, samples);
SpectrogramUtils.NormalizeSignal(ref @out);
return(@out);
}
}