private static double [] SpatialFrequency(double [] Signal)
{
Complex [] CompSignal;
CompSignal = ConvertToComplex(HanningWindow(Signal));
Fourier.FFT(CompSignal, FourierDirection.Forward);
return(NormalizedPositiveFrequencies(CompSignal));
}
public static double [] SyncCoefficients(double [] Signal)
{
Complex [] CompSignal;
double Sync;
double [] ReturnValue;
CompSignal = ConvertToComplex(HanningWindow(Signal));
Fourier.FFT(CompSignal, FourierDirection.Forward);
Sync = CompSignal[0].Magnitude;
ReturnValue = new double [CompSignal.Length / 2];
for (int i = 0; i < ReturnValue.Length; i++)
{
ReturnValue[i] = CompSignal[i].Magnitude / Sync;
}
ReturnValue[0] = 0;
return(ReturnValue);
}
public static double [] Autocorrelation(double [] Signal)
{
Complex [] InputSignal;
Complex [] Correlation;
InputSignal = ConvertToComplex(HanningWindow(Signal));
Fourier.FFT(InputSignal, FourierDirection.Forward);
InputSignal[0].Re = 0;
InputSignal[0].Im = 0;
Correlation = new Complex[InputSignal.Length];
for (int i = 0; i < InputSignal.Length; i++)
{
InputSignal[i] = InputSignal[i] / InputSignal.Length;
Correlation[i] = InputSignal[i] * InputSignal[i].Conjugate;
}
Fourier.FFT(Correlation, FourierDirection.Backward);
// Normalize by the value in the zeroth element of the array
return(MagnitudeAndSign(Correlation));
}
public static double [] Crosscorrelation(Complex [] SignalConjugate, double [] Signal)
{
Complex [] InputSignal;
Complex [] Correlation;
InputSignal = ConvertToComplex(HanningWindow(Signal));
Fourier.FFT(InputSignal, FourierDirection.Forward);
InputSignal[0].Re = 0;
InputSignal[0].Im = 0;
SignalConjugate[0].Re = 0;
SignalConjugate[0].Im = 0;
Correlation = new Complex[InputSignal.Length];
for (int i = 0; i < InputSignal.Length; i++)
{
InputSignal[i] = InputSignal[i] / InputSignal.Length;
Correlation[i] = InputSignal[i] * SignalConjugate[i];
}
Fourier.FFT(Correlation, FourierDirection.Backward);
// Normalize by the product of the standard deviations of the signal
return(MagnitudeAndSign(Correlation));
}
