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Work on Unit tests for mel and octave scale spectrograms.
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Issue #332
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@towsey
towsey committed Aug 6, 2020
1 parent 743fda8 commit 3efb633
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Showing 2 changed files with 107 additions and 44 deletions.
27 changes: 3 additions & 24 deletions src/AudioAnalysisTools/DSP/FrequencyScale.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,7 @@ public enum FreqScaleType
Mel = 1,
LinearOctaveStandard = 2,
Linear62OctaveTones31Nyquist11025 = 3,
Linear125OctaveTones30Nyquist11025 = 4,
Linear125OctaveTones32Nyquist11025 = 4,
Linear125OctaveTones28Nyquist32000 = 5,
Octaves24Nyquist32000 = 6,
OctaveDataReduction = 7,
Expand Down Expand Up @@ -66,7 +66,7 @@ public FrequencyScale(FreqScaleType type, int nyquist, int frameSize, int finalB
this.HertzGridInterval = hertzGridInterval;
if (type == FreqScaleType.Mel)
{
this.BinBounds = this.GetMelBinBounds();
this.BinBounds = MFCCStuff.GetMelBinBounds(this.Nyquist, this.FinalBinCount);
this.GridLineLocations = SpectrogramMelScale.GetMelGridLineLocations(this.HertzGridInterval, nyquist, this.FinalBinCount);
this.LinearBound = 1000;
}
Expand Down Expand Up @@ -100,7 +100,7 @@ public FrequencyScale(FreqScaleType fst)
}
else if (fst == FreqScaleType.Mel)
{
// TODO - This scale type is YET TO BE IMPLEMENTED.
// WARNING: Making this call will return a standard Mel scale where sr = 22050 and frameSize = 512
// MEL SCALE spectrograms are available by direct call to SpectrogramGenerator.Core.GetMelScaleSpectrogram()
SpectrogramMelScale.GetStandardMelScale(this);
}
Expand Down Expand Up @@ -221,27 +221,6 @@ public int GetBinIdInReducedSpectrogramForHerzValue(int herzValue)
return binBounds;
}

/// <summary>
/// Returns an [N, 2] matrix with bin ID in column 1 and lower Herz bound in column 2 but on Mel scale.
/// </summary>
public int[,] GetMelBinBounds()
{
double maxMel = (int)MFCCStuff.Mel(this.Nyquist);
int melBinCount = this.FinalBinCount;
double melPerBin = maxMel / melBinCount;

var binBounds = new int[this.FinalBinCount, 2];

for (int i = 0; i < melBinCount; i++)
{
binBounds[i, 0] = i;
double mel = i * melPerBin;
binBounds[i, 1] = (int)MFCCStuff.InverseMel(mel);
}

return binBounds;
}

/// <summary>
/// T.
/// </summary>
Expand Down
124 changes: 104 additions & 20 deletions tests/Acoustics.Test/AudioAnalysisTools/DSP/FrequencyScaleTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@ namespace Acoustics.Test.AudioAnalysisTools.DSP
using global::TowseyLibrary;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using SixLabors.ImageSharp;
using static global::TowseyLibrary.FFT;
using Path = System.IO.Path;

/// <summary>
Expand Down Expand Up @@ -184,17 +185,88 @@ public void LinearFrequencyScale()
/// Test of the default Mel FREQ SCALE
/// Check it on pure tone spectrum.
/// By default, the split between linear and log is at 1000 Hz.
/// NOTE: This mel frequency scale class is not actually used to produce Mel scale spectrograms.
/// Currently, the creation of mel scale spectrograms bypasses use of this FrequencyScale class.
/// </summary>
[TestMethod]
public void TestMelFrequencyScale()
{
// The Mel scale is not currently completed.
//It produces a shell only.
var fst = FreqScaleType.Mel;
var freqScale = new FrequencyScale(fst);

// test contents of the octave bin bounds matrix.
// test contents of the bin bounds matrix.
Assert.AreEqual(1000, freqScale.LinearBound);

// test contents of the octave bin bounds matrix.
int[,] melBinBounds = freqScale.BinBounds;
Assert.AreEqual(64, melBinBounds.GetLength(0));
Assert.AreEqual(1922, melBinBounds[30, 1]);
Assert.AreEqual(2164, melBinBounds[32, 1]);
Assert.AreEqual(10033, melBinBounds[62, 1]);
Assert.AreEqual(10516, melBinBounds[63, 1]);

// Check that freqScale.GridLineLocations are correct
var expected = new[,]
{
{ 20, 1000 },
{ 30, 2000 },
{ 37, 3000 },
{ 43, 4000 },
};

Assert.That.MatricesAreEqual(expected, freqScale.GridLineLocations);
}

/// <summary>
/// Test making a me-frequency spectrogram using an artificial amplitude spectrogram as input.
/// NOTE: This method bypasses the use of the FrequencyScale class.
/// By default, the Mel scale used here is linear to 1000 Hz.
/// </summary>
[TestMethod]
public void TestMakeMelScaleSpectrogram()
{
int sampleRate = 22050;
int windowSize = 512;
int defaultMelBinCount = 64;
var recordingBitsPerSample = 16;
var epsilon = Math.Pow(0.5, recordingBitsPerSample - 1);

// make fft class using rectangular window - just to get a value for Window power.
var fft = new FFT(windowSize);

var config = new SonogramConfig
{
WindowSize = windowSize,
WindowOverlap = 0.0,
SourceFName = "Dummy",
NoiseReductionType = NoiseReductionType.None,
NoiseReductionParameter = 0.0,
epsilon = epsilon,
WindowPower = fft.WindowPower,
};

// make a dummy spectrogram
int frameCount = 100;
int binCount = windowSize / 2;
double[,] matrix = new double[frameCount, binCount];
for (int i = 0; i < 100; i++)
{
matrix[i, 0] = 1.0;
matrix[i, 128] = 1.0;
matrix[i, 255] = 1.0;
}

var spectrogramMatrix = SpectrogramMelScale.MakeMelScaleSpectrogram(config, matrix, sampleRate);

//Assert.That.MatricesAreEqual(expected, actual);
Assert.AreEqual(frameCount, spectrogramMatrix.GetLength(0));
Assert.AreEqual(defaultMelBinCount, spectrogramMatrix.GetLength(1));

Assert.AreEqual(-73.784157442630288, spectrogramMatrix[0, 0], 0.0001);
Assert.AreEqual(-157.82548429035143, spectrogramMatrix[0, 1], 0.0001);
Assert.AreEqual(-157.82548429035143, spectrogramMatrix[0, 32], 0.0001);
Assert.AreEqual(-157.82548429035143, spectrogramMatrix[0, 62], 0.0001);
Assert.AreEqual(-98.078506874942121, spectrogramMatrix[0, 63], 0.0001);
}

/// <summary>
Expand Down Expand Up @@ -236,7 +308,7 @@ public void TestSplitLinearOctaveFrequencyScale()
linearSpectrum[128] = 1.0;
linearSpectrum[255] = 1.0;

double[] octaveSpectrum = OctaveFreqScale.OctaveSpectrum(octaveBinBounds, linearSpectrum);
double[] octaveSpectrum = OctaveFreqScale.ConvertLinearSpectrumToOctaveScale(octaveBinBounds, linearSpectrum);

Assert.AreEqual(103, octaveSpectrum.Length);
Assert.AreEqual(1.0, octaveSpectrum[0]);
Expand Down Expand Up @@ -264,7 +336,7 @@ public void OctaveFrequencyScale1()
var recording = new AudioRecording(recordingPath);

// default octave scale
var fst = FreqScaleType.Linear125OctaveTones30Nyquist11025;
var fst = FreqScaleType.Linear125OctaveTones32Nyquist11025;
var freqScale = new FrequencyScale(fst);

var sonoConfig = new SonogramConfig
Expand All @@ -276,18 +348,18 @@ public void OctaveFrequencyScale1()
NoiseReductionParameter = 0.0,
};

// Generate amplitude sonogram and then conver to octave scale
var sonogram = new AmplitudeSonogram(sonoConfig, recording.WavReader);
// Generate amplitude sonogram and then convert to octave scale
var amplitudeSpectrogram = new AmplitudeSonogram(sonoConfig, recording.WavReader);

// THIS IS THE CRITICAL LINE. COULD DO WITH SEPARATE UNIT TEST
sonogram.Data = OctaveFreqScale.ConvertAmplitudeSpectrogramToDecibelOctaveScale(sonogram.Data, freqScale);
// TODO THIS IS THE CRITICAL LINE. COULD DO WITH SEPARATE UNIT TEST
amplitudeSpectrogram.Data = OctaveFreqScale.ConvertAmplitudeSpectrogramToDecibelOctaveScale(amplitudeSpectrogram.Data, freqScale);

// DO NOISE REDUCTION
var dataMatrix = SNR.NoiseReduce_Standard(sonogram.Data);
sonogram.Data = dataMatrix;
sonogram.Configuration.WindowSize = freqScale.WindowSize;
var dataMatrix = SNR.NoiseReduce_Standard(amplitudeSpectrogram.Data);
amplitudeSpectrogram.Data = dataMatrix;
amplitudeSpectrogram.Configuration.WindowSize = freqScale.WindowSize;

var image = sonogram.GetImageFullyAnnotated(sonogram.GetImage(), "SPECTROGRAM: " + fst.ToString(), freqScale.GridLineLocations);
var image = amplitudeSpectrogram.GetImageFullyAnnotated(amplitudeSpectrogram.GetImage(), "SPECTROGRAM: " + fst.ToString(), freqScale.GridLineLocations);
image.Save(outputImagePath);

// NOTE: After fixing bugs in Octave Scale code, the following expected BinBounds is no longer correct.
Expand Down Expand Up @@ -411,11 +483,23 @@ public void OctaveFrequencyScale2()

// DO FILE EQUALITY TESTS
// Check that freqScale.OctaveBinBounds are correct
// WARNING: TODO FIX UP THIS TEST.
//var expectedBinBoundsFile = PathHelper.ResolveAsset("FrequencyScale", opFileStem + "_Octave2ScaleBinBounds.EXPECTED.json");
//var expectedBinBounds = Json.Deserialize<int[,]>(expectedBinBoundsFile);
//Assert.That.MatricesAreEqual(expectedBinBounds, freqScale.BinBounds);

var expectedBinBoundsFile = PathHelper.ResolveAsset("FrequencyScale", opFileStem + "_Octave2ScaleBinBounds.EXPECTED.json");
var expectedBinBounds = Json.Deserialize<int[,]>(expectedBinBoundsFile);

Assert.That.MatricesAreEqual(expectedBinBounds, freqScale.BinBounds);
// INSTEAD DO THIS TEST
Assert.AreEqual(257, freqScale.BinBounds.GetLength(0));
Assert.AreEqual(23, freqScale.BinBounds[23, 0]);
Assert.AreEqual(90, freqScale.BinBounds[23, 1]);
Assert.AreEqual(53, freqScale.BinBounds[52, 0]);
Assert.AreEqual(207, freqScale.BinBounds[52, 1]);
Assert.AreEqual(173, freqScale.BinBounds[100, 0]);
Assert.AreEqual(676, freqScale.BinBounds[100, 1]);
Assert.AreEqual(345, freqScale.BinBounds[128, 0]);
Assert.AreEqual(1348, freqScale.BinBounds[128, 1]);
Assert.AreEqual(8191, freqScale.BinBounds[256, 0]);
Assert.AreEqual(31996, freqScale.BinBounds[256, 1]);

// Check that freqScale.GridLineLocations are correct
var expected = new[,]
Expand All @@ -435,7 +519,7 @@ public void OctaveFrequencyScale2()

// Check that image dimensions are correct
Assert.AreEqual(201, image.Width);
Assert.AreEqual(310, image.Height);
Assert.AreEqual(311, image.Height);
}

/// <summary>
Expand Down Expand Up @@ -469,7 +553,7 @@ public void TestSpectralReductionScale()
linearSpectrum[128] = 1.0;
linearSpectrum[255] = 1.0;

double[] octaveSpectrum = OctaveFreqScale.OctaveSpectrum(freqScale.BinBounds, linearSpectrum);
double[] octaveSpectrum = OctaveFreqScale.ConvertLinearSpectrumToOctaveScale(freqScale.BinBounds, linearSpectrum);

Assert.AreEqual(20, octaveSpectrum.Length);
Assert.AreEqual(1.0, octaveSpectrum[0]);
Expand Down Expand Up @@ -601,7 +685,7 @@ public void TestFreqScaleOnArtificialSignal2()

// Check that image dimensions are correct
Assert.AreEqual(146, image.Width);
Assert.AreEqual(310, image.Height);
Assert.AreEqual(311, image.Height);
}
}
}

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