/* Method to extract spectral features.
Input arguments are the magnitude spectrum and block size */
void SpectralFeatures::extractFeatures(float* spectrum)
{
power = 0.0;
spectrum_sum = 0.0;
spectrum_abs_sum = 0.0;
halfwave = 0.0;
log_spectrum_sum = 0.0;
float diff_sum = 0.0;
for (int i=minBin; i<maxBin; i++) {
// Get power difference between consecutive spectra
//diff_sum += (spectrum[i] - fifo[i])*(spectrum[i] - fifo[i]);
diff_sum += ((spectrum[i] - fifo[i] + fabsf(spectrum[i] - fifo[i]))/2.0)*((spectrum[i] - fifo[i] + fabsf(spectrum[i] - fifo[i]))/2.0);
// // Half wave recitify the diff.
halfwave += ((spectrum[i] - fifo[i] + fabsf(spectrum[i] - fifo[i]))/2.0);
//Calculate the square
power += spectrum[i] * spectrum[i];
//Sum of the magnitude spectrum
spectrum_sum += spectrum[i];
//Sum of the absolute value of the magnitude spectrum
spectrum_abs_sum += fabsf(spectrum[i]);
//Logarithmic sum of the magnitude spectrum
log_spectrum_sum += log(spectrum[i]);
//Square of the magnitude spectrum
spectrum_sq[i] = spectrum[i] * spectrum[i];
}
/* Update fifo */
setFifo(spectrum,binSize);
if (!checkSilence(power)){
// Calculate Spectral Flux
calculateSpectralFlux(halfwave);
// Calculate Spectral Roloff
calculateSpectralRolloff(spectrum, spectrum_sum, 0.85);
//Calculate RMS
calculateRMS(power);
//Calculate Spectral Crest
calculateSpectralCrest(spectrum, spectrum_abs_sum);
//Calculate Spectral Centroid
calculateSpectralCentroid(spectrum, power, minBin, maxBin);
//Calculate Spectral Flatness
calculateSpectralFlatness(log_spectrum_sum, spectrum_sum);
}
}
/*! @brief Runs calculations on meter use statistics.
*
* After all the samples over a period have been collected, this routine is invoked.
*/
static void runCalculations(void)
{
uint8_t i;
//Loop through the samples to -1 the total sample length
for(i = 0; i < 15; i++)
{
calculateEnergy(VoltageSamples[i], CurrentSamples[i], bFALSE);
calculateRMS(VoltageSamples[i], bFALSE, RMS_VOLTAGE);
calculateRMS(CurrentSamples[i], bFALSE, RMS_CURRENT);
}
//Calculate the final values, indicating to the functions that all samples have been accounted for
calculateEnergy(VoltageSamples[15], CurrentSamples[15], bTRUE);
calculateRMS(VoltageSamples[15], bTRUE, RMS_VOLTAGE);
calculateRMS(CurrentSamples[15], bTRUE, RMS_CURRENT);
PerformingCalculations = bFALSE;
}