//=======================================================================
double OnsetDetectionFunction :: highFrequencySpectralDifferenceHWR()
{
double sum;
double mag_diff;
// perform the FFT
performFFT();
sum = 0; // initialise sum to zero
// compute phase values from fft output and sum deviations
for (int i = 0;i < frameSize;i++)
{
// calculate magnitude value
magSpec[i] = sqrt(pow(complexOut[i][0],2) + pow(complexOut[i][1],2));
// calculate difference
mag_diff = magSpec[i] - prevMagSpec[i];
if (mag_diff > 0)
{
sum = sum + (mag_diff*((double) (i+1)));
}
// store values for next calculation
prevMagSpec[i] = magSpec[i];
}
return sum;
}
//=======================================================================
double OnsetDetectionFunction :: complexSpectralDifferenceHWR()
{
double phaseDeviation;
double sum;
double magnitudeDifference;
double csd;
// perform the FFT
performFFT();
sum = 0; // initialise sum to zero
// compute phase values from fft output and sum deviations
for (int i = 0;i < frameSize;i++)
{
// calculate phase value
phase[i] = atan2(complexOut[i][1],complexOut[i][0]);
// calculate magnitude value
magSpec[i] = sqrt(pow(complexOut[i][0],2) + pow(complexOut[i][1],2));
// phase deviation
phaseDeviation = phase[i] - (2*prevPhase[i]) + prevPhase2[i];
// calculate magnitude difference (real part of Euclidean distance between complex frames)
magnitudeDifference = magSpec[i] - prevMagSpec[i];
// if we have a positive change in magnitude, then include in sum, otherwise ignore (half-wave rectification)
if (magnitudeDifference > 0)
{
// calculate complex spectral difference for the current spectral bin
csd = sqrt(pow(magSpec[i], 2) + pow(prevMagSpec[i], 2) - 2 * magSpec[i] * prevMagSpec[i] * cos(phaseDeviation));
// add to sum
sum = sum + csd;
}
// store values for next calculation
prevPhase2[i] = prevPhase[i];
prevPhase[i] = phase[i];
prevMagSpec[i] = magSpec[i];
}
return sum;
}
//=======================================================================
double OnsetDetectionFunction :: phaseDeviation()
{
double dev,pdev;
double sum;
// perform the FFT
performFFT();
sum = 0; // initialise sum to zero
// compute phase values from fft output and sum deviations
for (int i = 0;i < frameSize;i++)
{
// calculate phase value
phase[i] = atan2(complexOut[i][1],complexOut[i][0]);
// calculate magnitude value
magSpec[i] = sqrt(pow(complexOut[i][0],2) + pow(complexOut[i][1],2));
// if bin is not just a low energy bin then examine phase deviation
if (magSpec[i] > 0.1)
{
dev = phase[i] - (2*prevPhase[i]) + prevPhase2[i]; // phase deviation
pdev = princarg(dev); // wrap into [-pi,pi] range
// make all values positive
if (pdev < 0)
{
pdev = pdev*-1;
}
// add to sum
sum = sum + pdev;
}
// store values for next calculation
prevPhase2[i] = prevPhase[i];
prevPhase[i] = phase[i];
}
return sum;
}
//=======================================================================
double OnsetDetectionFunction :: spectralDifferenceHWR()
{
double diff;
double sum;
// perform the FFT
performFFT();
// compute first (N/2)+1 mag values
for (int i = 0;i < (frameSize/2)+1;i++)
{
magSpec[i] = sqrt(pow(complexOut[i][0],2) + pow(complexOut[i][1],2));
}
// mag spec symmetric above (N/2)+1 so copy previous values
for (int i = (frameSize/2)+1;i < frameSize;i++)
{
magSpec[i] = magSpec[frameSize-i];
}
sum = 0; // initialise sum to zero
for (int i = 0;i < frameSize;i++)
{
// calculate difference
diff = magSpec[i] - prevMagSpec[i];
// only add up positive differences
if (diff > 0)
{
// add difference to sum
sum = sum+diff;
}
// store magnitude spectrum bin for next detection function sample calculation
prevMagSpec[i] = magSpec[i];
}
return sum;
}
//=======================================================================
double OnsetDetectionFunction :: complexSpectralDifference()
{
double phaseDeviation;
double sum;
double csd;
// perform the FFT
performFFT();
sum = 0; // initialise sum to zero
// compute phase values from fft output and sum deviations
for (int i = 0;i < frameSize;i++)
{
// calculate phase value
phase[i] = atan2(complexOut[i][1],complexOut[i][0]);
// calculate magnitude value
magSpec[i] = sqrt(pow(complexOut[i][0],2) + pow(complexOut[i][1],2));
// phase deviation
phaseDeviation = phase[i] - (2*prevPhase[i]) + prevPhase2[i];
// calculate complex spectral difference for the current spectral bin
csd = sqrt(pow(magSpec[i], 2) + pow(prevMagSpec[i], 2) - 2 * magSpec[i] * prevMagSpec[i] * cos(phaseDeviation));
// add to sum
sum = sum + csd;
// store values for next calculation
prevPhase2[i] = prevPhase[i];
prevPhase[i] = phase[i];
prevMagSpec[i] = magSpec[i];
}
return sum;
}
// _______________________________________________________
void KeyWordDetector::getMFCCs() {
// First perform the FFT
performFFT();
// Try to reduce noise by estimated noise floor subtraction
spectralNoiseGating();
// Only half of the powerSpec vector [0-FFT_SIZE/2] now contains relevant information
// Calculate the power spectrum in place
powerSpectrum();
// Calculate the log mel energies will be size of NUM_MEL_FILTER_BANKS
melEnergy(logMelEn, powerSpec, FFT_SIZE/2, melBins, NUM_MEL_FILTER_BANKS+2);
// Compute the 12 needed mfccs by the adjusted discrete cosine transformation for 26
performDCT26Unrolled12MFCCs(currentMFCCs, logMelEn, dctCoeff);
//printV(logMelEn, 28, true);
}