public DefaultSpectrogramConfig()
{
Overlap = 64;
WdftSize = 2048;
FrequencyRange = Configs.FrequencyRanges.Default;
LogBase = 2;
LogBins = 32;
ImageLength = 128;
UseDynamicLogBase = true;
Stride = Configs.FingerprintStrides.Default;
Window = new HanningWindow();
}
public static Complex[] BandPassFilterFactors(double lowPassFreq, double highPassFreq, double sampleFreq, int filterLength, int n)
{
var window = new HanningWindow();
var windowFilterFactors = window.WindowFactors(filterLength);
var low = LowPassFilterFactors(lowPassFreq, sampleFreq, filterLength);
var high = HighPassFilterFactors(highPassFreq, sampleFreq, filterLength);
var lowWindowed = new double[n];
var highWindowed = new double[n];
for (int i = 0; i < filterLength; i++)
{
lowWindowed[i] = low[i] * windowFilterFactors[i];
highWindowed[i] = high[i] * windowFilterFactors[i];
}
for (int i = filterLength; i < n; i++)
{
lowWindowed[i] = 0;
highWindowed[i] = 0;
}
var shiftNumberFilter = (filterLength - 1) / 2;
var lowShiftedFilter = lowWindowed.Take(shiftNumberFilter);
var lowFilteredTemp = lowWindowed.Skip(shiftNumberFilter).ToList();
lowFilteredTemp.AddRange(lowShiftedFilter);
lowWindowed = lowFilteredTemp.ToArray();
var highShiftedFilter = highWindowed.Take(shiftNumberFilter);
var highFilteredTemp = highWindowed.Skip(shiftNumberFilter).ToList();
highFilteredTemp.AddRange(highShiftedFilter);
highWindowed = highFilteredTemp.ToArray();
var lowComplex = FourierTransform.FFT(lowWindowed);
var highComplex = FourierTransform.FFT(highWindowed);
var bandPass = new Complex[n];
for (int i = 0; i < n; i++)
{
bandPass[i] = lowComplex[i] * highComplex[i];
}
return(bandPass);
}
public DefaultSpectrogramConfig()
{
Overlap = 64;
WdftSize = 2048;
FrequencyRange = new FrequencyRange {
Min = 318, Max = 2000
};
LogBase = 2;
LogBins = 32;
ImageLength = 128;
UseDynamicLogBase = true;
NormalizeSignal = false;
Stride = new IncrementalStaticStride(1536);
Window = new HanningWindow();
}
public void WindowInPlaceTest()
{
const int length = 128 * 64;
float[] outerSpace = TestUtilities.GenerateRandomSingleArray(length);
float[] outerSpaceCopy = new float[outerSpace.Length];
outerSpace.CopyTo(outerSpaceCopy, 0);
var windowFunction = new HanningWindow();
windowFunction.WindowInPlace(outerSpace, outerSpace.Length);
WeightByHanningWindow(outerSpaceCopy);
for (int i = 0; i < outerSpace.Length; i++)
{
Assert.AreEqual(true, (outerSpace[i] - outerSpaceCopy[i]) < 0.00001);
}
}
public DefaultSpectrogramConfig()
{
Overlap = 64;
WdftSize = 2048;
FrequencyRange = Configs.FrequencyRanges.Default;
LogBase = 2;
LogBins = 32;
ImageLength = 128;
UseDynamicLogBase = true;
Stride = Configs.FingerprintStrides.Default;
Window = new HanningWindow();
ScalingFunction = (value, max) =>
{
float scaled = System.Math.Min(value / max, 1);
int domain = 255;
float c = (float)(1 / System.Math.Log(1 + domain));
return((float)(c * System.Math.Log(1 + scaled * domain)));
};
}
public ShortSamplesSpectrogramConfig()
{
// 11,6 ms is 64/5512 or 512/44100 or 372/32000
// The closest power of 2 in 2's complement format:
// 1024 / 32000 = 32 ms
// 512 / 32000 = 16 ms
// 256 / 32000 = 8 ms
Overlap = 1024; // Original 64
// 371 ms is 2048/5512 or 16384/44100 or 11889/32000
// The closest power of 2 in 2's complement format:
// 8192 / 32000 = 256 ms
// 4096 / 32000 = 128 ms
// 2048 / 32000 = 64 ms
// Due to using this on many small samples, we need to reduce the window and overlap sizes
// A transient is around 50 ms
WdftSize = 2048; // 4096; // Original 2048
FrequencyRange = new FrequencyRange(40, 16000); // Original FrequencyRange(318, 2000);
LogBase = System.Math.E; // Original 2
LogBins = 32;
ImageLength = 128; // Original 128
// calculate samples per fingerprint
//int samplesPerFingerprint = ImageLength * Overlap;
UseDynamicLogBase = false; // Original true
// 0,928 sec is 5115 / 5512 or 40924 / 44100 or 29695/32000
//Stride = new IncrementalStaticStride(29695, 0, samplesPerFingerprint); // Original IncrementalStaticStride(512);
// a static stride of 0 means no gaps between consecutive images (fingerprints)
Stride = new StaticStride(0); // Original IncrementalStaticStride(512);
Window = new HanningWindow();
ScalingFunction = (value, max) =>
{
float scaled = System.Math.Min(value / max, 1);
int domain = 255;
float c = (float)(1 / System.Math.Log(1 + domain));
return((float)(c * System.Math.Log(1 + scaled * domain)));
};
}
