public void TestFreqScaleOnArtificialSignal1()
{
int sampleRate = 22050;
double duration = 20; // signal duration in seconds
int[] harmonics = { 500, 1000, 2000, 4000, 8000 };
int windowSize = 512;
var freqScale = new FrequencyScale(sampleRate / 2, windowSize, 1000);
var outputImagePath = Path.Combine(this.outputDirectory.FullName, "Signal1_LinearFreqScale.png");
var recording = DspFilters.GenerateTestRecording(sampleRate, duration, harmonics, WaveType.Cosine);
var sonoConfig = new SonogramConfig
{
WindowSize = freqScale.WindowSize,
WindowOverlap = 0.0,
SourceFName = "Signal1",
NoiseReductionType = NoiseReductionType.Standard,
NoiseReductionParameter = 0.12,
};
var sonogram = new AmplitudeSonogram(sonoConfig, recording.WavReader);
// pick a row, any row
var oneSpectrum = MatrixTools.GetRow(sonogram.Data, 40);
oneSpectrum = DataTools.filterMovingAverage(oneSpectrum, 5);
var peaks = DataTools.GetPeaks(oneSpectrum);
for (int i = 5; i < peaks.Length - 5; i++)
{
if (peaks[i])
{
LoggedConsole.WriteLine($"bin ={freqScale.BinBounds[i, 0]}, Herz={freqScale.BinBounds[i, 1]}-{freqScale.BinBounds[i + 1, 1]} ");
}
}
foreach (int h in harmonics)
{
LoggedConsole.WriteLine($"Harmonic {h}Herz should be in bin {freqScale.GetBinIdForHerzValue(h)}");
}
// spectrogram without framing, annotation etc
var image = sonogram.GetImage();
string title = $"Spectrogram of Harmonics: {DataTools.Array2String(harmonics)} SR={sampleRate} Window={windowSize}";
image = sonogram.GetImageFullyAnnotated(image, title, freqScale.GridLineLocations);
image.Save(outputImagePath);
// Check that image dimensions are correct
Assert.AreEqual(861, image.Width);
Assert.AreEqual(310, image.Height);
Assert.IsTrue(peaks[11]);
Assert.IsTrue(peaks[22]);
Assert.IsTrue(peaks[45]);
Assert.IsTrue(peaks[92]);
Assert.IsTrue(peaks[185]);
}
public void TestFreqScaleOnArtificialSignal2()
{
int sampleRate = 64000;
double duration = 30; // signal duration in seconds
int[] harmonics = { 500, 1000, 2000, 4000, 8000 };
var freqScale = new FrequencyScale(FreqScaleType.Linear125Octaves7Tones28Nyquist32000);
var outputImagePath = Path.Combine(this.outputDirectory.FullName, "Signal2_OctaveFreqScale.png");
var recording = DspFilters.GenerateTestRecording(sampleRate, duration, harmonics, WaveType.Cosine);
// init the default sonogram config
var sonoConfig = new SonogramConfig
{
WindowSize = freqScale.WindowSize,
WindowOverlap = 0.2,
SourceFName = "Signal2",
NoiseReductionType = NoiseReductionType.None,
NoiseReductionParameter = 0.0,
};
var sonogram = new AmplitudeSonogram(sonoConfig, recording.WavReader);
sonogram.Data = OctaveFreqScale.ConvertAmplitudeSpectrogramToDecibelOctaveScale(sonogram.Data, freqScale);
// pick a row, any row
var oneSpectrum = MatrixTools.GetRow(sonogram.Data, 40);
oneSpectrum = DataTools.filterMovingAverage(oneSpectrum, 5);
var peaks = DataTools.GetPeaks(oneSpectrum);
var peakIds = new List <int>();
for (int i = 5; i < peaks.Length - 5; i++)
{
if (peaks[i])
{
int peakId = freqScale.BinBounds[i, 0];
peakIds.Add(peakId);
LoggedConsole.WriteLine($"Spectral peak located in bin {peakId}, Herz={freqScale.BinBounds[i, 1]}");
}
}
foreach (int h in harmonics)
{
LoggedConsole.WriteLine($"Harmonic {h}Herz should be in bin {freqScale.GetBinIdForHerzValue(h)}");
}
Assert.AreEqual(5, peakIds.Count);
Assert.AreEqual(129, peakIds[0]);
Assert.AreEqual(257, peakIds[1]);
Assert.AreEqual(513, peakIds[2]);
Assert.AreEqual(1025, peakIds[3]);
Assert.AreEqual(2049, peakIds[4]);
var image = sonogram.GetImage();
string title = $"Spectrogram of Harmonics: {DataTools.Array2String(harmonics)} SR={sampleRate} Window={freqScale.WindowSize}";
image = sonogram.GetImageFullyAnnotated(image, title, freqScale.GridLineLocations);
image.Save(outputImagePath);
// Check that image dimensions are correct
Assert.AreEqual(146, image.Width);
Assert.AreEqual(310, image.Height);
}