/// <summary>
/// Data Window application on a time series.
/// </summary>
/// <param name="index">Position for Calculation the window values </param>
/// <param name="datalenght">Length of the Data array, where should be applied the window</param>
/// <param name="_window">class windowfuction member</param>
/// <param name="gaussA">Parameter for the Gauss window function if used</param>
/// <returns>The calculated Window Value, for given position.</returns>
public static double WindowAtIndex(int index, int datalenght, windowFunction _window, double gaussA)
{
double win = 1; // weight factor according to the data
if (_window == windowFunction.uniform || _window == windowFunction.none)
{
win = 1d;
}
else if (_window == windowFunction.Barlett)
{
win = 1d - Math.Abs((2d * (double)index / datalenght) - 1d);
}
else if (_window == windowFunction.TurkeyHann)
{
win = 0.5d + 0.5d * Math.Cos(2d * Math.PI * (((double)index / (double)datalenght) - 0.5d));
}
else if (_window == windowFunction.Hamming)
{
win = 0.54d + 0.46d * Math.Cos(2d * Math.PI * (((double)index / (double)datalenght) - 0.5d));
}
else if (_window == windowFunction.Gauss)
{
win = Math.Exp(-0.5d * Math.Pow(2d * gaussA * (((double)index / (double)datalenght) - 0.5d), 2d));
}
return(win);
}
/// <summary>
/// Compensates the Energy on Fourier analysis after applying a Data window
/// </summary>
/// <param name="_window">class windowfuction member</param>
/// <param name="DataLength">Length of the Data array, where should be applied the window enerdy decompensation.</param>
/// <param name="GaussA">Parameter for the Gauss window function if used</param>
/// <returns>The calculated Energy lost for decompensation.</returns>
public static double WindowEnergyLostDecompensation(windowFunction _window, int DataLength, double GaussA)
{
double fac = 1d; // factor
if (_window == windowFunction.Barlett)
{
fac = 2d;
}
else if (_window == windowFunction.TurkeyHann)
{
fac = 2d;
}
else if (_window == windowFunction.Hamming)
{
double win = 1d;
for (double i = 0; i < (double)DataLength; i++)
{
win = 0.54d + 0.46d * Math.Cos(2d * Math.PI * ((i / ((double)DataLength - 1d)) - 0.5d));
fac += win;
}
fac = ((double)DataLength - 1d) / fac;
}
else if (_window == windowFunction.Gauss)
{
double win = 1d;
for (double i = 0; i < (double)DataLength; i++)
{
win = Math.Exp(-0.5d * Math.Pow(2d * GaussA * ((i / ((double)DataLength - 1d)) - 0.5d), 2d));
fac += win;
}
fac = ((double)DataLength - 1d) / fac;
}
else
{
fac = 1;
}
return(fac);
}
/// <summary>
/// Data Window application on a time series.
/// </summary>
/// <param name="data">Data to applicate the Window</param>
/// <param name="_window">class windowfuction member</param>
/// <param name="pbar">Forms.Prgogressbar</param>
public static double[] Window(double[] data, windowFunction _window, ProgressBar pbar)
{
if (_window == windowFunction.uniform || _window == windowFunction.none)
{
pbar.Value += (data.Length - 1);
return(data);
}
int l2 = (data.Length - 1) / 2;
int l22 = l2 + l2;
int M1 = l2 + 1;
int M2 = l2 - 1;
data[0] = 0d;
data[data.Length - 1] = 0d;
double F = 0d;
for (int i = l2; i < l22; i++)
{
double t = (l2 - (double)i) / l2;
if (_window == windowFunction.Barlett)
{
F = 1 + t; // 1- math.abs(t);
}
if (_window == windowFunction.TurkeyHann)
{
F = 0.5d * (1d + Math.Cos(Math.PI * t));
}
if (_window == windowFunction.Hamming)
{
F = 0.54d + 0.46d * Math.Cos(Math.PI * t);
}
data[l2 + (i - l2)] *= F;
data[l2 - (i - l2)] *= F;
pbar.Value += 2;
}
return(data);
}
