/// <summary>
/// Create Frequency Table
/// </summary>
/// <param name="basefreq">Minimum frequency in Hertz</param>
/// <param name="bands">Number of frequency bands</param>
/// <param name="bandsperoctave">Frequency resolution in Bands Per Octave</param>
/// <returns>Frequency Array</returns>
public static double[] FrequencyArray(double basefreq, int bands, double bandsperoctave)
{
int i = 0;
double[] freq = new double[bands];
double maxfreq;
if (LOGBASE == 1.0)
{
maxfreq = bandsperoctave; // in linear mode we use bpo to store the maxfreq since we couldn't deduce maxfreq otherwise
}
else
{
maxfreq = basefreq * Math.Pow(LOGBASE, ((double)(bands - 1) / bandsperoctave));
}
for (i = 0; i < bands; i++)
{
freq[i] = GlobalMembersDsp.LogPositionToFrequency((double)i / (double)(bands - 1), basefreq, maxfreq); //band's central freq
}
if (GlobalMembersDsp.LogPositionToFrequency((double)bands / (double)(bands - 1), basefreq, maxfreq) > 0.5)
{
// TODO change sampling rate instead
Console.Write("Warning: Upper frequency limit above Nyquist frequency\n");
}
return(freq);
}
/// <summary>
/// Noise synthesis mode
/// </summary>
/// <param name="d">Image</param>
/// <param name="Xsize">Specifies the desired width of the spectrogram</param>
/// <param name="bands">Specifies the desired height of the spectrogram (bands)</param>
/// <param name="samplecount">Number of samples</param>
/// <param name="samplerate">Sample rate</param>
/// <param name="basefreq">Base frequency in Hertz</param>
/// <param name="pixpersec">Time resolution in Pixels Per Second</param>
/// <param name="bpo">Frequency resolution in Bands Per Octave</param>
/// <returns></returns>
public static double[] SynthesizeNoise(ref double[][] d, ref int Xsize, ref int bands, ref int samplecount, ref int samplerate, ref double basefreq, ref double pixpersec, ref double bpo)
{
double[] s; // final signal
double coef;
double[] noise; // filtered looped noise
double loop_size_sec = LOOP_SIZE_SEC; // size of the filter bank loop, in seconds. Later to be taken from user input
int loop_size = 0; // size of the filter bank loop, in samples. Deduced from loop_size_sec
int loop_size_min = 0; // minimum required size for the filter bank loop, in samples. Calculated from the longest windowed sinc's length
double[] pink_noise; // original pink noise (in the frequency domain)
double mag; // parameters for the creation of pink_noise's samples
double phase;
double[] envelope; // interpolated envelope
double[] lut; // Blackman Sqaure look-up table
double[] freq; // frequency look-up table
double maxfreq; // central frequency of the last band
int i = 0; // general purpose iterator
int ib = 0; // bands iterator
int il = 0; // loop iterator
int Fa = 0; // Fa is the index of the band's start in the frequency domain
int Fd = 0; // Fd is the index of the band's end in the frequency domain
double La; // La is the log2 of the frequency of Fa
double Ld; // Ld is the log2 of the frequency of Fd
double Li; // Li is the iterative frequency between La and Ld defined logarithmically
freq = GlobalMembersDsp.FrequencyArray(basefreq, bands, bpo);
if (LOGBASE == 1.0)
{
maxfreq = bpo; // in linear mode we use bpo to store the maxfreq since we couldn't deduce maxfreq otherwise
}
else
{
maxfreq = basefreq * Math.Pow(LOGBASE, ((double)(bands - 1) / bpo));
}
clockA = GlobalMembersUtil.GetTime();
samplecount = (int)GlobalMembersUtil.RoundOff(Xsize / pixpersec); // calculation of the length of the final signal
Console.Write("Sound duration : {0:f3} s\n", (double)samplecount / samplerate);
// allocation of the final signal
s = new double[samplecount];
// allocation of the interpolated envelope
envelope = new double[samplecount];
//********Loop size calculation********
loop_size = (int)loop_size_sec * samplerate;
if (LOGBASE == 1.0)
{
loop_size_min = (int)GlobalMembersUtil.RoundOff(4.0 * 5.0 / freq[1] - freq[0]); // linear mode
}
else
{
loop_size_min = (int)GlobalMembersUtil.RoundOff(2.0 * 5.0 / ((freq[0] * Math.Pow(2.0, -1.0 / (bpo))) * (1.0 - Math.Pow(2.0, -1.0 / bpo)))); // this is the estimate of how many samples the longest FIR will take up in the time domain
}
if (loop_size_min > loop_size)
{
loop_size = loop_size_min;
}
loop_size = GlobalMembersUtil.NextPrime(loop_size); // enlarge the loop_size to the next multiple of short primes in order to make IFFTs faster
//--------Loop size calculation--------
//********Pink noise generation********
pink_noise = new double[loop_size];
for (i = 1; i < (loop_size + 1) >> 1; i++)
{
mag = Math.Pow((double)i, 0.5 - 0.5 * LOGBASE); // FIXME something's not necessarily right with that formula
phase = GlobalMembersUtil.DoubleRandom() * PI; // random phase between -pi and +pi
pink_noise[i] = mag * Math.Cos(phase); // real part
pink_noise[loop_size - i] = mag * Math.Sin(phase); // imaginary part
}
//--------Pink noise generation--------
// allocate noise
noise = new double[loop_size];
lut = GlobalMembersDsp.BlackmanSquareLookupTable(ref BMSQ_LUT_SIZE); // Blackman Square look-up table initalisation
for (ib = 0; ib < bands; ib++)
{
Console.Write("{0,4:D}/{1:D}\r", ib + 1, bands);
// reset filtered noise
for (i = 0; i < loop_size; i++)
{
noise[i] = 0; // reset sband
}
//********Filtering********
Fa = (int)GlobalMembersUtil.RoundOff(GlobalMembersDsp.LogPositionToFrequency((double)(ib - 1) / (double)(bands - 1), basefreq, maxfreq) * loop_size);
Fd = (int)GlobalMembersUtil.RoundOff(GlobalMembersDsp.LogPositionToFrequency((double)(ib + 1) / (double)(bands - 1), basefreq, maxfreq) * loop_size);
La = GlobalMembersDsp.FrequencyToLogPosition((double)Fa / (double)loop_size, basefreq, maxfreq);
Ld = GlobalMembersDsp.FrequencyToLogPosition((double)Fd / (double)loop_size, basefreq, maxfreq);
if (Fd > loop_size / 2)
{
Fd = loop_size / 2; // stop reading if reaching the Nyquist frequency
}
if (Fa < 1)
{
Fa = 1;
}
Console.Write("{0,4:D}/{1:D} {2:f2} Hz - {3:f2} Hz\r", ib + 1, bands, (double)Fa * samplerate / loop_size, (double)Fd * samplerate / loop_size);
for (i = Fa; i < Fd; i++)
{
Li = GlobalMembersDsp.FrequencyToLogPosition((double)i / (double)loop_size, basefreq, maxfreq); // calculation of the logarithmic position
Li = (Li - La) / (Ld - La);
coef = 0.5 - 0.5 * Math.Cos(2.0 * PI * Li); // Hann function
noise[i + 1] = pink_noise[i + 1] * coef;
noise[loop_size - 1 - i] = pink_noise[loop_size - 1 - i] * coef;
}
//--------Filtering--------
GlobalMembersDsp.FFT(ref noise, ref noise, loop_size, FFTMethod.IDFT); // IFFT of the filtered noise
// blank the envelope
for (i = 0; i < samplecount; i++)
{
envelope[i] = 0; // reset sband
}
GlobalMembersDsp.BlackmanSquareInterpolation(ref d[bands - ib - 1], ref envelope, ref Xsize, ref samplecount, ref lut, BMSQ_LUT_SIZE); // interpolation of the envelope
il = 0;
for (i = 0; i < samplecount; i++)
{
s[i] += envelope[i] * noise[il]; // modulation
il++; // increment loop iterator
if (il == loop_size) // if the array iterator has reached the end of the array, it's reset
{
il = 0;
}
}
}
Console.Write("\n");
GlobalMembersDsp.Normalize(ref s, ref samplecount, 1.0);
return(s);
}
/// <summary>
/// Analyze the input
/// </summary>
/// <param name="s">Sound (original signal)</param>
/// <param name="samplecount">Sample count (samplecount is the original signal's orginal length)</param>
/// <param name="samplerate">Sample rate</param>
/// <param name="Xsize">Specifies the desired width of the spectrogram</param>
/// <param name="bands">Specifies the desired height of the spectrogram (bands is the total count of bands)</param>
/// <param name="bpo">Frequency resolution in Bands Per Octave</param>
/// <param name="pixpersec">Time resolution in Pixels Per Second</param>
/// <param name="basefreq">Minimum frequency in Hertz</param>
/// <returns>Image</returns>
public static double[][] Analyze(ref double[] s, ref int samplecount, ref int samplerate, ref int Xsize, ref int bands, ref double bpo, ref double pixpersec, ref double basefreq)
{
int i = 0; // i is a general purpose iterator
int ib = 0; // ib is the band iterator
int Mb = 0; // Mb is the length of the original signal once zero-padded (always even)
int Mc = 0; // Mc is the length of the filtered signal
int Md = 0; // Md is the length of the envelopes once downsampled (constant)
int Fa = 0; // Fa is the index of the band's start in the frequency domain
int Fd = 0; // Fd is the index of the band's end in the frequency domain
double[][] @out; // @out is the output image
double[] h;
double[] freq; // freq is the band's central frequency
double[] t; // t is temporary pointer to a new version of the signal being worked on
double coef; // coef is a temporary modulation coefficient
double La; // La is the log2 of the frequency of Fa
double Ld; // Ld is the log2 of the frequency of Fd
double Li; // Li is the iterative frequency between La and Ld defined logarithmically
double maxfreq; // maxfreq is the central frequency of the last band
freq = GlobalMembersDsp.FrequencyArray(basefreq, bands, bpo);
if (LOGBASE == 1.0)
{
maxfreq = bpo; // in linear mode we use bpo to store the maxfreq since we couldn't deduce maxfreq otherwise
}
else
{
maxfreq = basefreq * Math.Pow(LOGBASE, ((double)(bands - 1) / bpo));
}
Xsize = (int)(samplecount * pixpersec);
if (GlobalMembersUtil.FMod((double)samplecount * pixpersec, 1.0) != 0.0)
{
// round-up
Xsize++;
}
Console.Write("Image size : {0:D}x{1:D}\n", Xsize, bands);
@out = new double[bands][];
clockA = GlobalMembersUtil.GetTime();
//********ZEROPADDING******** Note : Don't do it in Circular mode
// Mb is the length of the original signal once zero-padded (always even)
if (LOGBASE == 1.0)
{
Mb = samplecount - 1 + (int)GlobalMembersUtil.RoundOff(5.0 / freq[1] - freq[0]); // linear mode
}
else
{
Mb = samplecount - 1 + (int)GlobalMembersUtil.RoundOff(2.0 * 5.0 / ((freq[0] * Math.Pow(LOGBASE, -1.0 / (bpo))) * (1.0 - Math.Pow(LOGBASE, -1.0 / bpo))));
}
if (Mb % 2 == 1) // if Mb is odd
{
Mb++; // make it even (for the sake of simplicity)
}
Mc = 0;
Md = 0;
Mb = (int)GlobalMembersUtil.RoundOff((double)GlobalMembersUtil.NextPrime((int)GlobalMembersUtil.RoundOff(Mb * pixpersec)) / pixpersec);
// Md is the length of the envelopes once downsampled (constant)
Md = (int)GlobalMembersUtil.RoundOff(Mb * pixpersec);
// realloc to the zeropadded size
Array.Resize <double>(ref s, Mb);
// zero-out the padded area. Equivalent of : for (i=samplecount; i<Mb; i++) s[i] = 0;
for (i = samplecount; i < Mb; i++)
{
s[i] = 0;
}
//--------ZEROPADDING--------
//Export.exportCSV(String.Format("samples_before_fft.csv"), s, 256);
GlobalMembersDsp.FFT(ref s, ref s, Mb, FFTMethod.DFT); // In-place FFT of the original zero-padded signal
//Export.exportCSV(String.Format("samples_after_fft.csv"), s, 256);
for (ib = 0; ib < bands; ib++)
{
//********Filtering********
Fa = (int)GlobalMembersUtil.RoundOff(GlobalMembersDsp.LogPositionToFrequency((double)(ib - 1) / (double)(bands - 1), basefreq, maxfreq) * Mb);
Fd = (int)GlobalMembersUtil.RoundOff(GlobalMembersDsp.LogPositionToFrequency((double)(ib + 1) / (double)(bands - 1), basefreq, maxfreq) * Mb);
La = GlobalMembersDsp.FrequencyToLogPosition((double)Fa / (double)Mb, basefreq, maxfreq);
Ld = GlobalMembersDsp.FrequencyToLogPosition((double)Fd / (double)Mb, basefreq, maxfreq);
if (Fd > Mb / 2)
{
Fd = Mb / 2; // stop reading if reaching the Nyquist frequency
}
if (Fa < 1)
{
Fa = 1;
}
// Mc is the length of the filtered signal
Mc = (Fd - Fa) * 2 + 1;
// '*2' because the filtering is on both real and imaginary parts,
// '+1' for the DC.
// No Nyquist component since the signal length is necessarily odd
if (Md > Mc) // if the band is going to be too narrow
{
Mc = Md;
}
if (Md < Mc) // round the larger bands up to the next integer made of 2^n * 3^m
{
Mc = GlobalMembersUtil.NextPrime(Mc);
}
Console.Write("{0,4:D}/{1:D} (FFT size: {2,6:D}) {3:f2} Hz - {4:f2} Hz\r", ib + 1, bands, Mc, (double)Fa * samplerate / Mb, (double)Fd * samplerate / Mb);
@out[bands - ib - 1] = new double[Mc + 1];
for (i = 0; i < Fd - Fa; i++)
{
Li = GlobalMembersDsp.FrequencyToLogPosition((double)(i + Fa) / (double)Mb, basefreq, maxfreq); // calculation of the logarithmic position
Li = (Li - La) / (Ld - La);
coef = 0.5 - 0.5 * Math.Cos(2.0 * PI * Li); // Hann function
@out[bands - ib - 1][i + 1] = s[i + 1 + Fa] * coef;
@out[bands - ib - 1][Mc - 1 - i] = s[Mb - Fa - 1 - i] * coef;
}
//--------Filtering--------
//Export.exportCSV(String.Format("test/band_{0}_filtered.csv", bands-ib-1), @out[bands-ib-1]);
//********90° rotation********
h = new double[Mc + 1];
// Rotation : Re' = Im; Im' = -Re
for (i = 0; i < Fd - Fa; i++)
{
h[i + 1] = @out[bands - ib - 1][Mc - 1 - i]; // Re' = Im
h[Mc - 1 - i] = -@out[bands - ib - 1][i + 1]; // Im' = -Re
}
//--------90° rotation--------
//********Envelope detection********
//Export.exportCSV(String.Format("test/band_{0}_rotated.csv", bands-ib-1), @out[bands-ib-1]);
GlobalMembersDsp.FFT(ref @out[bands - ib - 1], ref @out[bands - ib - 1], Mc, FFTMethod.IDFT); // In-place IFFT of the filtered band signal
GlobalMembersDsp.FFT(ref h, ref h, Mc, FFTMethod.IDFT); // In-place IFFT of the filtered band signal rotated by 90°
//Export.exportCSV(String.Format("test/band_{0}_before.csv", bands-ib-1), @out[bands-ib-1]);
for (i = 0; i < Mc; i++)
{
// TODO: why does the above crash?!
//for (i = 0; i < @out[bands-ib-1].Length; i++) {
// Magnitude of the analytic signal
double x = @out[bands - ib - 1][i];
double y = h[i];
double xSquared = x * x;
double ySquared = y * y;
double mag = Math.Sqrt(xSquared + ySquared);
@out[bands - ib - 1][i] = mag;
}
Array.Clear(h, 0, h.Length);
//--------Envelope detection--------
//********Downsampling********
if (Mc < Md) // if the band doesn't have to be resampled
{
Array.Resize <double>(ref @out[bands - ib - 1], Md); // simply ignore the end of it
}
if (Mc > Md) // If the band *has* to be downsampled
{
t = @out[bands - ib - 1];
@out[bands - ib - 1] = GlobalMembersDsp.BlackmanDownsampling(@out[bands - ib - 1], Mc, Md); // Blackman downsampling
Array.Clear(t, 0, t.Length);
}
//--------Downsampling--------
Array.Resize <double>(ref @out[bands - ib - 1], Xsize); // Tail chopping
//Export.exportCSV(String.Format("test/band_{0}_after.csv", bands-ib-1), @out[bands-ib-1]);
}
Console.Write("\n");
GlobalMembersDsp.Normalize(ref @out, ref Xsize, ref bands, 1.0);
//Export.exportCSV(String.Format("out.csv"), @out);
return(@out);
}