public static float[] ValuesByWindow(int frameSIZE, bool causal, WindowType windowType)
{
switch (windowType)
{
case WindowType.Rectangle:
return(SignalWindow.Rectangle(frameSIZE, causal));
case WindowType.VonnHann:
return(SignalWindow.VonHann(frameSIZE, causal));
case WindowType.Hamming:
return(SignalWindow.Hamming(frameSIZE, causal));
default:
return(SignalWindow.Rectangle(frameSIZE, causal));
}
}
public static float[] MultiplyByWindow(float[] data, bool causal, WindowType windowType)
{
switch (windowType)
{
case WindowType.Rectangle:
return(SignalWindow.RectangleMultiply(data, causal));
case WindowType.VonnHann:
return(SignalWindow.VonHannMultiply(data, causal));
case WindowType.Hamming:
return(SignalWindow.HammingMultiply(data, causal));
default:
return(SignalWindow.RectangleMultiply(data, causal));
}
}
public static float[] CreateImpulseSignal(int size, float cutOffFrequency, int sampleRate, WindowType windowType, bool causal)
{
return(SignalWindow.MultiplyByWindow(CreateImpulseSignal(size, cutOffFrequency, sampleRate), causal, windowType));
}
public static float[] SignalFilterFreq(float[] signal, int frameSize, int frameOffset,
int filterSize, float filterCutoff, WindowType windowType, bool causal)
{
float[] impulse = Helper.CreateImpulseSignal(filterSize, filterCutoff, 44100);
int powerTwo = 0;
for (int p = 2; p <= 120000; p *= 2)
{
if (p >= frameSize + impulse.Length - 1)
{
powerTwo = p;
break;
}
}
float[] filter = new float[powerTwo];
if (causal)
{
filter = Helper.AddZerosAfter(impulse, powerTwo - impulse.Length);
}
else
{
filter = Helper.AddZerosInMiddle(impulse, powerTwo - impulse.Length);
}
float[][] frames = CreateFrames(signal, frameSize, frameOffset);
float[] result = new float[signal.Length + filter.Length - frameSize];
Complex[] fftFilter = filter.Select(v => new Complex(v, 0)).ToArray();
fftFilter = Audio.Classes.AudioHelper.FFT(fftFilter, true);
float[] windowValues = SignalWindow.ValuesByWindow(frameSize, true, windowType);
for (int i = 0; i < frames.Length; i++)
{
float[] frame = new float[frameSize];
for (int j = 0; j < frame.Length; j++)
{
frame[j] = frames[i][j] * windowValues[j]; // każda ramka wymnożona przez wartości okna
}
float[] frameWithZeros = AddZerosAfter(frame, filter.Length - frames[i].Length); // uzupełniamy zerami na końcu ramki
float[] appliedFilter = FilterPerFrameFreq(frameWithZeros, fftFilter);
for (int j = 0; j < appliedFilter.Length; j++)
{
result[i * frameOffset + j] += appliedFilter[j];
}
}
float multi = 1 / result.Max();
for (int i = 0; i < result.Length; i++)
{
result[i] *= multi;
}
return(result);
}