public Bitmap to_image(ref double[] signal, int samplerate)
{
Console.Out.WriteLine("Transforming input");
Complex[] spectrum = GlobalMembersSpectrogram.padded_FFT(signal);
//const size_t width = (spectrum.size()-1)*2*pixpersec/samplerate;
double w1 = spectrum.Length - 1;
double w2 = (double)pixpersec / (double)samplerate;
double w3 = w1 * 2 * w2;
int width = (int)w3;
// transformation of frequency in hz to index in spectrum
//const double filterscale = ((double)spectrum.size()*2)/samplerate;
double filterscale = ((double)spectrum.Length * 2) / samplerate;
Console.Out.WriteLine("filterscale: {0}", filterscale);
Filterbank filterbank = Filterbank.get_filterbank(frequency_axis, filterscale, basefreq, bandwidth, overlap);
int bands = (int)filterbank.num_bands_est(maxfreq);
int top_index = (int)(maxfreq * filterscale);
// maxfreq has to be at most nyquist
Debug.Assert(top_index <= spectrum.Length);
//std::vector<real_vec> image_data;
List <double[]> image_data = new List <double[]>();
for (int bandidx = 0;; ++bandidx)
{
band_progress(bandidx, bands);
// filtering
Pair <int, int> range = filterbank.get_band(bandidx);
Console.Out.WriteLine("-----");
Console.Out.WriteLine("spectrum size: {0}", spectrum.Length);
Console.Out.WriteLine("lowidx: {0:0.00} highidx: {1:0.00}", range.First, range.Second);
Console.Out.WriteLine("(real)lowfreq: {0:0.00} (real)highfreq: {1:0.00}", range.First / filterscale, range.Second / filterscale);
Console.Out.WriteLine("actual width: {0:0.00} hz", (range.Second - range.First) / filterscale);
Console.Out.WriteLine("vertical values: {0:0.00}", (range.Second - range.First));
Console.Out.WriteLine("crowd sample: {0:0.00}", (range.Second - range.First - 1) * 2);
Console.Out.WriteLine("theoretically staci: {0:0.00} hz samplerate", 2 * (range.Second - range.First) / filterscale);
Console.Out.WriteLine("width: {0}", width);
int filterbandLength = range.Second - range.First;
Complex[] filterband = new Complex[filterbandLength];
//std::copy(spectrum.begin()+range.first,
// spectrum.begin()+std::min(range.second, top_index),
// filterband.begin());
int sourceIndexStart = range.First;
int sourceIndexEnd = Math.Min(range.Second, top_index);
int length = sourceIndexEnd - sourceIndexStart;
Array.Copy(spectrum, sourceIndexStart, filterband, 0, length);
if (range.First > top_index)
{
break;
}
if (range.Second > top_index)
{
int start = top_index - range.First;
//std::fill(filterband.begin()+top_index-range.first,
// filterband.end(), Complex(0,0));
break; // TODO: fix above
}
// windowing
apply_window(ref filterband, range.First, filterscale);
// envelope detection + resampling
double[] envelope = GlobalMembersSpectrogram.resample(GlobalMembersSpectrogram.get_envelope(ref filterband), width);
image_data.Add(envelope);
}
GlobalMembersSpectrogram.normalize_image_cutoff_negative(ref image_data);
return(make_image(image_data));
}
