public LogFilterbank(double scale, double @base, double centsperband, double overlap)
{
scale_ = scale;
centsperband_ = centsperband;
logstart_ = SpectrogramUtils.Freq2Cent(@base);
logstep_ = (1 - overlap) * centsperband_;
Console.Out.WriteLine("Cents per band: {0}", centsperband_);
Console.Out.WriteLine("Logstep: {0}", logstep_);
Debug.Assert(logstep_ > 0);
}
public void ApplyWindow(ref Complex[] chunk, int lowidx, double filterscale)
{
int highidx = lowidx + chunk.Length;
if (frequency_axis == AxisScale.SCALE_LINEAR)
{
for (int i = 0; i < chunk.Length; ++i)
{
chunk[i] *= SpectrogramUtils.WindowCoef((double)i / (chunk.Length - 1), window);
}
}
else
{
double rloglow = SpectrogramUtils.Freq2Cent(lowidx / filterscale); // after rounding
double rloghigh = SpectrogramUtils.Freq2Cent((highidx - 1) / filterscale);
for (int i = 0; i < chunk.Length; ++i)
{
double logidx = SpectrogramUtils.Freq2Cent((lowidx + i) / filterscale);
double winidx = (logidx - rloglow) / (rloghigh - rloglow);
chunk[i] *= SpectrogramUtils.WindowCoef(winidx, window);
}
}
}
public override double NumBandsEst(double maxfreq)
{
return((SpectrogramUtils.Freq2Cent(maxfreq) - logstart_) / logstep_ + 4);
}