public void TestDecibelSpectrogram()
{
var recording = new AudioRecording(PathHelper.ResolveAsset("Recordings", "BAC2_20071008-085040.wav"));
// specfied linear scale
var freqScale = new FrequencyScale(nyquist: 11025, frameSize: 1024, hertzGridInterval: 1000);
var sonoConfig = new SonogramConfig
{
WindowSize = freqScale.FinalBinCount * 2,
WindowOverlap = 0.2,
SourceFName = recording.BaseName,
NoiseReductionType = NoiseReductionType.None,
NoiseReductionParameter = 0.0,
};
// DO EQUALITY TEST on the AMPLITUDE SONGOGRAM DATA
// Do not bother with the image because this is only an amplitude spectrogram.
var sonogram = new AmplitudeSonogram(sonoConfig, recording.WavReader);
// DO FILE EQUALITY TEST on the DECIBEL SONGOGRAM DATA
// Do not bother with the image because this has been tested elsewhere.
var decibelSonogram = MFCCStuff.DecibelSpectra(sonogram.Data, sonogram.Configuration.WindowPower, sonogram.SampleRate, sonogram.Configuration.epsilon);
var expectedFile = PathHelper.ResolveAsset("StandardSonograms", "BAC2_20071008_DecibelSonogramData.EXPECTED.bin");
// run this once to generate expected test data
// uncomment this to update the binary data. Should be rarely needed
// AT: Updated 2017-02-15 because FFT library changed in 864f7a491e2ea0e938161bd390c1c931ecbdf63c
//Binary.Serialize(expectedFile, decibelSonogram);
var expected = Binary.Deserialize <double[, ]>(expectedFile);
CollectionAssert.That.AreEqual(expected, decibelSonogram, EnvelopeAndFftTests.Delta);
}
//##################################################################################################################################
/// <summary>
/// NOTE!!!! The decibel array has been normalised in 0 - 1.
/// </summary>
protected static Tuple <double[, ], double[]> MakeCepstrogram(SonogramConfig config, double[,] matrix, double[] decibels, int sampleRate)
{
double[,] m = matrix;
int nyquist = sampleRate / 2;
double epsilon = config.epsilon;
bool includeDelta = config.mfccConfig.IncludeDelta;
bool includeDoubleDelta = config.mfccConfig.IncludeDoubleDelta;
//Log.WriteIfVerbose(" MakeCepstrogram(matrix, decibels, includeDelta=" + includeDelta + ", includeDoubleDelta=" + includeDoubleDelta + ")");
//(i) APPLY FILTER BANK
int bandCount = config.mfccConfig.FilterbankCount;
bool doMelScale = config.mfccConfig.DoMelScale;
int ccCount = config.mfccConfig.CcCount;
int fftBinCount = config.FreqBinCount; //number of Hz bands = 2^N +1. Subtract DC bin
int minHz = config.MinFreqBand ?? 0;
int maxHz = config.MaxFreqBand ?? nyquist;
Log.WriteIfVerbose("ApplyFilterBank(): Dim prior to filter bank =" + matrix.GetLength(1));
//error check that filterBankCount < FFTbins
if (bandCount > fftBinCount)
{
throw new Exception(
"## FATAL ERROR in BaseSonogram.MakeCepstrogram():- Can't calculate cepstral coeff. FilterbankCount > FFTbins. (" +
bandCount + " > " + fftBinCount + ")\n\n");
}
//this is the filter count for full bandwidth 0-Nyquist. This number is trimmed proportionately to fit the required bandwidth.
if (doMelScale)
{
m = MFCCStuff.MelFilterBank(m, bandCount, nyquist, minHz, maxHz); // using the Greg integral
}
else
{
m = MFCCStuff.LinearFilterBank(m, bandCount, nyquist, minHz, maxHz);
}
Log.WriteIfVerbose("\tDim after filter bank=" + m.GetLength(1) + " (Max filter bank=" + bandCount + ")");
//(ii) CONVERT AMPLITUDES TO DECIBELS
m = MFCCStuff.DecibelSpectra(m, config.WindowPower, sampleRate, epsilon); //from spectrogram
//(iii) NOISE REDUCTION
var tuple1 = SNR.NoiseReduce(m, config.NoiseReductionType, config.NoiseReductionParameter);
m = tuple1.Item1;
//(iv) calculate cepstral coefficients
m = MFCCStuff.Cepstra(m, ccCount);
//(v) NormaliseMatrixValues
m = DataTools.normalise(m);
//(vi) Calculate the full range of MFCC coefficients ie including decibel and deltas, etc
m = MFCCStuff.AcousticVectors(m, decibels, includeDelta, includeDoubleDelta);
var tuple2 = Tuple.Create(m, tuple1.Item2);
return(tuple2); // return matrix and full bandwidth modal noise profile
}
public void SonogramDecibelMethodsAreEquivalent()
{
var recording = new AudioRecording(PathHelper.ResolveAsset("Recordings", "BAC2_20071008-085040.wav"));
// specfied linear scale
var freqScale = new FrequencyScale(nyquist: 11025, frameSize: 1024, hertzGridInterval: 1000);
var sonoConfig = new SonogramConfig
{
WindowSize = freqScale.FinalBinCount * 2,
WindowOverlap = 0.2,
SourceFName = recording.BaseName,
NoiseReductionType = NoiseReductionType.None,
NoiseReductionParameter = 0.0,
};
// Method 1
var sonogram = new AmplitudeSonogram(sonoConfig, recording.WavReader);
var expectedDecibelSonogram = MFCCStuff.DecibelSpectra(sonogram.Data, sonogram.Configuration.WindowPower, sonogram.SampleRate, sonogram.Configuration.epsilon);
// Method 2: make sure that the decibel spectrum is the same no matter which path we take to calculate it.
var actualDecibelSpectrogram = new SpectrogramStandard(sonoConfig, recording.WavReader);
CollectionAssert.That.AreEqual(expectedDecibelSonogram, actualDecibelSpectrogram.Data, EnvelopeAndFftTests.Delta);
}
public void SonogramDecibelMethodsAreEquivalent()
{
// Method 1
var sonogram = new AmplitudeSonogram(this.sonoConfig, this.recording.WavReader);
var expectedDecibelSonogram = MFCCStuff.DecibelSpectra(sonogram.Data, sonogram.Configuration.WindowPower, sonogram.SampleRate, sonogram.Configuration.epsilon);
// Method 2: make sure that the decibel spectrum is the same no matter which path we take to calculate it.
var actualDecibelSpectrogram = new SpectrogramStandard(this.sonoConfig, this.recording.WavReader);
CollectionAssert.That.AreEqual(expectedDecibelSonogram, actualDecibelSpectrogram.Data, EnvelopeAndFftTests.Delta);
}
private double[,] SobelEdgegram(double[,] matrix)
{
double[,] m = MFCCStuff.DecibelSpectra(matrix, this.Configuration.WindowPower, this.SampleRate, this.Configuration.epsilon); //from spectrogram
//double[,] m = Speech.DecibelSpectra(matrix);
//NOISE REDUCTION
var output = SNR.NoiseReduce(m, this.Configuration.NoiseReductionType, this.Configuration.NoiseReductionParameter);
this.SnrData.ModalNoiseProfile = output.Item2;
return(ImageTools.SobelEdgeDetection(output.Item1));
}
public static double[,] GetDecibelSpectrogramNoiseReduced(AudioRecording recording, int frameSize)
{
int frameStep = frameSize;
// get decibel spectrogram
var results = DSP_Frames.ExtractEnvelopeAndAmplSpectrogram(recording.WavReader.Samples, recording.SampleRate, recording.Epsilon, frameSize, frameStep);
var spectrogram = MFCCStuff.DecibelSpectra(results.AmplitudeSpectrogram, results.WindowPower, recording.SampleRate, recording.Epsilon);
// remove background noise from spectrogram
double[] spectralDecibelBgn = NoiseProfile.CalculateBackgroundNoise(spectrogram);
spectrogram = SNR.TruncateBgNoiseFromSpectrogram(spectrogram, spectralDecibelBgn);
spectrogram = SNR.RemoveNeighbourhoodBackgroundNoise(spectrogram, nhThreshold: 3.0);
return(spectrogram);
}
/// <summary>
/// Initializes a new instance of the <see cref="DecibelSpectrogram"/> class.
/// </summary>
public DecibelSpectrogram(AmplitudeSpectrogram amplitudeSpectrogram)
{
this.Configuration = amplitudeSpectrogram.Configuration;
this.Attributes = amplitudeSpectrogram.Attributes;
// (ii) CONVERT AMPLITUDES TO DECIBELS
this.Data = MFCCStuff.DecibelSpectra(amplitudeSpectrogram.Data, this.Attributes.WindowPower, this.Attributes.SampleRate, this.Attributes.Epsilon);
// (iii) NOISE REDUCTION
var tuple = SNR.NoiseReduce(this.Data, this.Configuration.NoiseReductionType, this.Configuration.NoiseReductionParameter);
this.Data = tuple.Item1; // store data matrix
if (this.SnrData != null)
{
this.SnrData.ModalNoiseProfile = tuple.Item2; // store the full bandwidth modal noise profile
}
}
public void TestDecibelSpectrogram()
{
// DO EQUALITY TEST on the AMPLITUDE SONGOGRAM DATA
// Do not bother with the image because this is only an amplitude spectrogram.
var sonogram = new AmplitudeSonogram(this.sonoConfig, this.recording.WavReader);
// DO FILE EQUALITY TEST on the DECIBEL SONGOGRAM DATA
// Do not bother with the image because this has been tested elsewhere.
var decibelSonogram = MFCCStuff.DecibelSpectra(sonogram.Data, sonogram.Configuration.WindowPower, sonogram.SampleRate, sonogram.Configuration.epsilon);
var expectedFile = PathHelper.ResolveAsset("StandardSonograms", "BAC2_20071008_DecibelSonogramData.EXPECTED.bin");
// run this once to generate expected test data
// uncomment this to update the binary data. Should be rarely needed
// AT: Updated 2017-02-15 because FFT library changed in 864f7a491e2ea0e938161bd390c1c931ecbdf63c
//Binary.Serialize(expectedFile, decibelSonogram);
var expected = Binary.Deserialize <double[, ]>(expectedFile);
CollectionAssert.That.AreEqual(expected, decibelSonogram, EnvelopeAndFftTests.Delta);
}
public void TestStandardNoiseRemoval()
{
var recording = new AudioRecording(PathHelper.ResolveAsset("Recordings", "BAC2_20071008-085040.wav"));
int windowSize = 512;
var sr = recording.SampleRate;
// window overlap is used only for sonograms. It is not used when calculating acoustic indices.
double windowOverlap = 0.0;
var windowFunction = WindowFunctions.HAMMING.ToString();
var fftdata = DSP_Frames.ExtractEnvelopeAndFfts(
recording,
windowSize,
windowOverlap,
windowFunction);
// Now recover the data
// The following data is required when constructing sonograms
//var duration = recording.WavReader.Time;
//var frameCount = fftdata.FrameCount;
//var fractionOfHighEnergyFrames = fftdata.FractionOfHighEnergyFrames;
double[,] deciBelSpectrogram = MFCCStuff.DecibelSpectra(fftdata.AmplitudeSpectrogram, fftdata.WindowPower, sr, fftdata.Epsilon);
// The following call to NoiseProfile.CalculateBackgroundNoise(double[,] spectrogram)
// returns a noise profile that is used as the BGN spectral index.
// It calculates the modal background noise for each freqeuncy bin and then returns a smoothed version.
// By default, the number of SDs = 0 and the smoothing window = 7.
// Method assumes that the passed spectrogram is oriented as: rows=frames, cols=freq bins.</param>
double[] spectralDecibelBgn = NoiseProfile.CalculateBackgroundNoise(deciBelSpectrogram);
var resourcesDir = PathHelper.ResolveAssetPath("Indices");
var expectedSpectrumFile = new FileInfo(resourcesDir + "\\NoiseProfile.bin");
//Binary.Serialize(expectedSpectrumFile, spectralDecibelBgn);
var expectedVector = Binary.Deserialize <double[]>(expectedSpectrumFile);
CollectionAssert.That.AreEqual(expectedVector, spectralDecibelBgn, 0.000_000_001);
}
} // LocalPeaks()
/// <summary>
/// CALCULATEs SPECTRAL PEAK TRACKS: spectralIndices.SPT, RHZ, RVT, RPS, RNG
/// This method is only called from IndexCalulate.analysis() when the IndexCalculation Duration is less than 10 seconds,
/// because need to recalculate background noise etc.
/// Otherwise the constructor of this class is called: sptInfo = new SpectralPeakTracks(decibelSpectrogram, peakThreshold);
/// NOTE: We require a noise reduced decibel spectrogram
/// FreqBinWidth can be accessed, if required, through dspOutput1.FreqBinWidth.
/// </summary>
public static SpectralPeakTracks CalculateSpectralPeakTracks(AudioRecording recording, int sampleStart, int sampleEnd, int frameSize, bool octaveScale, double peakThreshold)
{
double epsilon = recording.Epsilon;
int sampleRate = recording.WavReader.SampleRate;
int bufferFrameCount = 2; // 2 because must allow for edge effects when using 5x5 grid to find ridges.
int ridgeBuffer = frameSize * bufferFrameCount;
var ridgeRecording = AudioRecording.GetRecordingSubsegment(recording, sampleStart, sampleEnd, ridgeBuffer);
int frameStep = frameSize;
var dspOutput = DSP_Frames.ExtractEnvelopeAndFfts(ridgeRecording, frameSize, frameStep);
// Generate the ridge SUBSEGMENT deciBel spectrogram from the SUBSEGMENT amplitude spectrogram
// i: generate the SUBSEGMENT deciBel spectrogram from the SUBSEGMENT amplitude spectrogram
double[,] decibelSpectrogram;
if (octaveScale)
{
var freqScale = new FrequencyScale(FreqScaleType.Linear125Octaves7Tones28Nyquist32000);
decibelSpectrogram = OctaveFreqScale.DecibelSpectra(dspOutput.AmplitudeSpectrogram, dspOutput.WindowPower, sampleRate, epsilon, freqScale);
}
else
{
decibelSpectrogram = MFCCStuff.DecibelSpectra(dspOutput.AmplitudeSpectrogram, dspOutput.WindowPower, sampleRate, epsilon);
}
// calculate the noise profile
var spectralDecibelBgn = NoiseProfile.CalculateBackgroundNoise(decibelSpectrogram);
decibelSpectrogram = SNR.TruncateBgNoiseFromSpectrogram(decibelSpectrogram, spectralDecibelBgn);
double nhDecibelThreshold = 2.0; // SPECTRAL dB THRESHOLD for smoothing background
decibelSpectrogram = SNR.RemoveNeighbourhoodBackgroundNoise(decibelSpectrogram, nhDecibelThreshold);
// thresholds in decibels
// double frameStepDuration = frameStep / (double)sampleRate; // fraction of a second
// TimeSpan frameStepTimeSpan = TimeSpan.FromTicks((long)(frameStepDuration * TimeSpan.TicksPerSecond));
var sptInfo = new SpectralPeakTracks(decibelSpectrogram, peakThreshold);
return(sptInfo);
}
}//end CONSTRUCTOR
public override void Make(double[,] amplitudeM)
{
double[,] m = amplitudeM;
// (i) IF REQUIRED CONVERT TO FULL BAND WIDTH MEL SCALE
// Make sure you have Configuration.MelBinCount somewhere
if (this.Configuration.DoMelScale)
{
m = MFCCStuff.MelFilterBank(m, this.Configuration.MelBinCount, this.NyquistFrequency, 0, this.NyquistFrequency); // using the Greg integral
}
// (ii) CONVERT AMPLITUDES TO DECIBELS
m = MFCCStuff.DecibelSpectra(m, this.Configuration.WindowPower, this.SampleRate, this.Configuration.epsilon);
// (iii) NOISE REDUCTION
var tuple = SNR.NoiseReduce(m, this.Configuration.NoiseReductionType, this.Configuration.NoiseReductionParameter);
this.Data = tuple.Item1; // store data matrix
if (this.SnrData != null)
{
this.SnrData.ModalNoiseProfile = tuple.Item2; // store the full bandwidth modal noise profile
}
}
//////public static IndexCalculateResult Analysis(
public static SpectralIndexValuesForContentDescription Analysis(
AudioRecording recording,
TimeSpan segmentOffsetTimeSpan,
int sampleRateOfOriginalAudioFile,
bool returnSonogramInfo = false)
{
// returnSonogramInfo = true; // if debugging
double epsilon = recording.Epsilon;
int sampleRate = recording.WavReader.SampleRate;
//var segmentDuration = TimeSpan.FromSeconds(recording.WavReader.Time.TotalSeconds);
var indexCalculationDuration = TimeSpan.FromSeconds(ContentSignatures.IndexCalculationDurationInSeconds);
// Get FRAME parameters for the calculation of Acoustic Indices
int frameSize = ContentSignatures.FrameSize;
int frameStep = frameSize; // that is, windowOverlap = zero
double frameStepDuration = frameStep / (double)sampleRate; // fraction of a second
var frameStepTimeSpan = TimeSpan.FromTicks((long)(frameStepDuration * TimeSpan.TicksPerSecond));
// INITIALISE a RESULTS STRUCTURE TO return
// initialize a result object in which to store SummaryIndexValues and SpectralIndexValues etc.
var config = new IndexCalculateConfig(); // sets some default values
int freqBinCount = frameSize / 2;
var indexProperties = GetIndexProperties();
////////var result = new IndexCalculateResult(freqBinCount, indexProperties, indexCalculationDuration, segmentOffsetTimeSpan, config);
var spectralIndices = new SpectralIndexValuesForContentDescription();
///////result.SummaryIndexValues = null;
///////SpectralIndexValues spectralIndices = result.SpectralIndexValues;
// set up default spectrogram to return
///////result.Sg = returnSonogramInfo ? GetSonogram(recording, windowSize: 1024) : null;
///////result.Hits = null;
///////result.TrackScores = new List<Plot>();
// ################################## FINISHED SET-UP
// ################################## NOW GET THE AMPLITUDE SPECTROGRAM
// EXTRACT ENVELOPE and SPECTROGRAM FROM RECORDING SEGMENT
// Note that the amplitude spectrogram has had the DC bin removed. i.e. has only 256 columns.
var dspOutput1 = DSP_Frames.ExtractEnvelopeAndFfts(recording, frameSize, frameStep);
var amplitudeSpectrogram = dspOutput1.AmplitudeSpectrogram;
// (B) ################################## EXTRACT OSC SPECTRAL INDEX DIRECTLY FROM THE RECORDING ##################################
// Get the oscillation spectral index OSC separately from signal because need a different frame size etc.
var sampleLength = Oscillations2014.DefaultSampleLength;
var frameLength = Oscillations2014.DefaultFrameLength;
var sensitivity = Oscillations2014.DefaultSensitivityThreshold;
var spectralIndexShort = Oscillations2014.GetSpectralIndex_Osc(recording, frameLength, sampleLength, sensitivity);
// double length of the vector because want to work with 256 element vector for spectrogram purposes
spectralIndices.OSC = DataTools.VectorDoubleLengthByAverageInterpolation(spectralIndexShort);
// (C) ################################## EXTRACT SPECTRAL INDICES FROM THE AMPLITUDE SPECTROGRAM ##################################
// IFF there has been UP-SAMPLING, calculate bin of the original audio nyquist. this will be less than SR/2.
// original sample rate can be anything 11.0-44.1 kHz.
int originalNyquist = sampleRateOfOriginalAudioFile / 2;
// if up-sampling has been done
if (dspOutput1.NyquistFreq > originalNyquist)
{
dspOutput1.NyquistFreq = originalNyquist;
dspOutput1.NyquistBin = (int)Math.Floor(originalNyquist / dspOutput1.FreqBinWidth); // note that bin width does not change
}
// ii: CALCULATE THE ACOUSTIC COMPLEXITY INDEX
spectralIndices.ACI = AcousticComplexityIndex.CalculateAci(amplitudeSpectrogram);
// iii: CALCULATE the H(t) or Temporal ENTROPY Spectrum and then reverse the values i.e. calculate 1-Ht for energy concentration
double[] temporalEntropySpectrum = AcousticEntropy.CalculateTemporalEntropySpectrum(amplitudeSpectrogram);
for (int i = 0; i < temporalEntropySpectrum.Length; i++)
{
temporalEntropySpectrum[i] = 1 - temporalEntropySpectrum[i];
}
spectralIndices.ENT = temporalEntropySpectrum;
// (C) ################################## EXTRACT SPECTRAL INDICES FROM THE DECIBEL SPECTROGRAM ##################################
// i: Convert amplitude spectrogram to decibels and calculate the dB background noise profile
double[,] decibelSpectrogram = MFCCStuff.DecibelSpectra(dspOutput1.AmplitudeSpectrogram, dspOutput1.WindowPower, sampleRate, epsilon);
double[] spectralDecibelBgn = NoiseProfile.CalculateBackgroundNoise(decibelSpectrogram);
spectralIndices.BGN = spectralDecibelBgn;
// ii: Calculate the noise reduced decibel spectrogram derived from segment recording.
// REUSE the var decibelSpectrogram but this time using dspOutput1.
decibelSpectrogram = MFCCStuff.DecibelSpectra(dspOutput1.AmplitudeSpectrogram, dspOutput1.WindowPower, sampleRate, epsilon);
decibelSpectrogram = SNR.TruncateBgNoiseFromSpectrogram(decibelSpectrogram, spectralDecibelBgn);
decibelSpectrogram = SNR.RemoveNeighbourhoodBackgroundNoise(decibelSpectrogram, nhThreshold: 2.0);
// iii: CALCULATE noise reduced AVERAGE DECIBEL SPECTRUM
spectralIndices.PMN = SpectrogramTools.CalculateAvgDecibelSpectrumFromDecibelSpectrogram(decibelSpectrogram);
// ######################################################################################################################################################
// iv: CALCULATE SPECTRAL COVER. NOTE: at this point, decibelSpectrogram is noise reduced. All values >= 0.0
// FreqBinWidth can be accessed, if required, through dspOutput1.FreqBinWidth
// dB THRESHOLD for calculating spectral coverage
double dBThreshold = ActivityAndCover.DefaultActivityThresholdDb;
// Calculate lower and upper boundary bin ids.
// Boundary between low & mid frequency bands is to avoid low freq bins containing anthropogenic noise. These biased index values away from bio-phony.
int midFreqBound = config.MidFreqBound;
int lowFreqBound = config.LowFreqBound;
int lowerBinBound = (int)Math.Ceiling(lowFreqBound / dspOutput1.FreqBinWidth);
int middleBinBound = (int)Math.Ceiling(midFreqBound / dspOutput1.FreqBinWidth);
var spActivity = ActivityAndCover.CalculateSpectralEvents(decibelSpectrogram, dBThreshold, frameStepTimeSpan, lowerBinBound, middleBinBound);
//spectralIndices.CVR = spActivity.CoverSpectrum;
spectralIndices.EVN = spActivity.EventSpectrum;
///////result.TrackScores = null;
///////return result;
return(spectralIndices);
} // end calculation of Six Spectral Indices
/// <summary>
/// Calculate summary statistics for supplied temporal and spectral targets.
/// </summary>
/// <remarks>
/// The acoustic statistics calculated in this method are based on methods outlined in
/// "Acoustic classification of multiple simultaneous bird species: A multi-instance multi-label approach",
/// by Forrest Briggs, Balaji Lakshminarayanan, Lawrence Neal, Xiaoli Z.Fern, Raviv Raich, Sarah J.K.Hadley, Adam S. Hadley, Matthew G. Betts, et al.
/// The Journal of the Acoustical Society of America v131, pp4640 (2012); doi: http://dx.doi.org/10.1121/1.4707424
/// ..
/// The Briggs feature are calculated from the column (freq bin) and row (frame) sums of the extracted spectrogram.
/// 1. Gini Index for frame and bin sums. A measure of dispersion. Problem with gini is that its value is dependent on the row or column count.
/// We use entropy instead because value not dependent on row or column count because it is normalized.
/// For the following meausres of k-central moments, the freq and time values are normalized in 0,1 to width of the event.
/// 2. freq-mean
/// 3. freq-variance
/// 4. freq-skew and kurtosis
/// 5. time-mean
/// 6. time-variance
/// 7. time-skew and kurtosis
/// 8. freq-max (normalized)
/// 9. time-max (normalized)
/// 10. Briggs et al also calculate a 16 value histogram of gradients for each event mask. We do not do that here although we could.
/// ...
/// NOTE 1: There are differences between our method of noise reduction and Briggs. Briggs does not convert to decibels
/// and instead works with power values. He obtains a noise profile from the 20% of frames having the lowest energy sum.
/// NOTE 2: To NormaliseMatrixValues for noise, they divide the actual energy by the noise value. This is equivalent to subtraction when working in decibels.
/// There are advantages and disadvantages to Briggs method versus ours. In our case, we hve to convert decibel values back to
/// energy values when calculating the statistics for the extracted acoustic event.
/// NOTE 3: We do not calculate the higher central moments of the time/frequency profiles, i.e. skew and kurtosis.
/// Ony mean and standard deviation.
/// ..
/// NOTE 4: This method assumes that the passed event occurs totally within the passed recording,
/// AND that the passed recording is of sufficient duration to obtain reliable BGN noise profile
/// BUT not so long as to cause memory constipation.
/// </remarks>
/// <param name="recording">as type AudioRecording which contains the event</param>
/// <param name="temporalTarget">Both start and end bounds - relative to the supplied recording</param>
/// <param name="spectralTarget">both bottom and top bounds in Hertz</param>
/// <param name="config">parameters that determine the outcome of the analysis</param>
/// <param name="segmentStartOffset">How long since the start of the recording this event occurred</param>
/// <returns>an instance of EventStatistics</returns>
public static EventStatistics AnalyzeAudioEvent(
AudioRecording recording,
Range <TimeSpan> temporalTarget,
Range <double> spectralTarget,
EventStatisticsConfiguration config,
TimeSpan segmentStartOffset)
{
var stats = new EventStatistics
{
EventStartSeconds = temporalTarget.Minimum.TotalSeconds,
EventEndSeconds = temporalTarget.Maximum.TotalSeconds,
LowFrequencyHertz = spectralTarget.Minimum,
HighFrequencyHertz = spectralTarget.Maximum,
SegmentDurationSeconds = recording.Duration.TotalSeconds,
SegmentStartSeconds = segmentStartOffset.TotalSeconds,
};
// temporal target is supplied relative to recording, but not the supplied audio segment
// shift coordinates relative to segment
var localTemporalTarget = temporalTarget.Shift(-segmentStartOffset);
if (!recording
.Duration
.AsRangeFromZero(Topology.Inclusive)
.Contains(localTemporalTarget))
{
stats.Error = true;
stats.ErrorMessage =
$"Audio not long enough ({recording.Duration}) to analyze target ({localTemporalTarget})";
return(stats);
}
// convert recording to spectrogram
int sampleRate = recording.SampleRate;
double epsilon = recording.Epsilon;
// extract the spectrogram
var dspOutput1 = DSP_Frames.ExtractEnvelopeAndFfts(recording, config.FrameSize, config.FrameStep);
double hertzBinWidth = dspOutput1.FreqBinWidth;
var stepDurationInSeconds = config.FrameStep / (double)sampleRate;
var startFrame = (int)Math.Ceiling(localTemporalTarget.Minimum.TotalSeconds / stepDurationInSeconds);
// subtract 1 frame because want to end before start of end point.
var endFrame = (int)Math.Floor(localTemporalTarget.Maximum.TotalSeconds / stepDurationInSeconds) - 1;
var bottomBin = (int)Math.Floor(spectralTarget.Minimum / hertzBinWidth);
var topBin = (int)Math.Ceiling(spectralTarget.Maximum / hertzBinWidth);
// Events can have their high value set to the nyquist.
// Since the submatrix call below uses an inclusive upper bound an index out of bounds exception occurs in
// these cases. So we just ask for the bin below.
if (topBin >= config.FrameSize / 2)
{
topBin = (config.FrameSize / 2) - 1;
}
// Convert amplitude spectrogram to deciBels and calculate the dB background noise profile
double[,] decibelSpectrogram = MFCCStuff.DecibelSpectra(dspOutput1.AmplitudeSpectrogram, dspOutput1.WindowPower, sampleRate, epsilon);
double[] spectralDecibelBgn = NoiseProfile.CalculateBackgroundNoise(decibelSpectrogram);
decibelSpectrogram = SNR.TruncateBgNoiseFromSpectrogram(decibelSpectrogram, spectralDecibelBgn);
decibelSpectrogram = SNR.RemoveNeighbourhoodBackgroundNoise(decibelSpectrogram, nhThreshold: 2.0);
// extract the required acoustic event
var eventMatrix = MatrixTools.Submatrix(decibelSpectrogram, startFrame, bottomBin, endFrame, topBin);
// Get the SNR of the event. This is just the max value in the matrix because noise reduced
MatrixTools.MinMax(eventMatrix, out _, out double max);
stats.SnrDecibels = max;
// Now need to convert event matrix back to energy values before calculating other statistics
eventMatrix = MatrixTools.Decibels2Power(eventMatrix);
var columnAverages = MatrixTools.GetColumnAverages(eventMatrix);
var rowAverages = MatrixTools.GetRowAverages(eventMatrix);
// calculate the mean and temporal standard deviation in decibels
NormalDist.AverageAndSD(rowAverages, out double mean, out double stddev);
stats.MeanDecibels = 10 * Math.Log10(mean);
stats.TemporalStdDevDecibels = 10 * Math.Log10(stddev);
// calculate the frequency standard deviation in decibels
NormalDist.AverageAndSD(columnAverages, out mean, out stddev);
stats.FreqBinStdDevDecibels = 10 * Math.Log10(stddev);
// calculate relative location of the temporal maximum
int maxRowId = DataTools.GetMaxIndex(rowAverages);
stats.TemporalMaxRelative = maxRowId / (double)rowAverages.Length;
// calculate the entropy dispersion/concentration indices
stats.TemporalEnergyDistribution = 1 - DataTools.EntropyNormalised(rowAverages);
stats.SpectralEnergyDistribution = 1 - DataTools.EntropyNormalised(columnAverages);
// calculate the spectral centroid and the dominant frequency
double binCentroid = CalculateSpectralCentroid(columnAverages);
stats.SpectralCentroid = (int)Math.Round(hertzBinWidth * binCentroid) + (int)spectralTarget.Minimum;
int maxColumnId = DataTools.GetMaxIndex(columnAverages);
stats.DominantFrequency = (int)Math.Round(hertzBinWidth * maxColumnId) + (int)spectralTarget.Minimum;
// remainder of this method is to produce debugging images. Can comment out when not debugging.
/*
* var normalisedIndex = DataTools.NormaliseMatrixValues(columnAverages);
* var image4 = GraphsAndCharts.DrawGraph("columnSums", normalisedIndex, 100);
* string path4 = @"C:\SensorNetworks\Output\Sonograms\UnitTestSonograms\columnSums.png";
* image4.Save(path4);
* normalisedIndex = DataTools.NormaliseMatrixValues(rowAverages);
* image4 = GraphsAndCharts.DrawGraph("rowSums", normalisedIndex, 100);
* path4 = @"C:\SensorNetworks\Output\Sonograms\UnitTestSonograms\rowSums.png";
* image4.Save(path4);
*/
return(stats);
}
public static void Main(Arguments arguments)
{
//1. set up the necessary files
//DirectoryInfo diSource = arguments.Source.Directory;
FileInfo fiSourceRecording = arguments.Source;
FileInfo fiConfig = arguments.Config.ToFileInfo();
FileInfo fiImage = arguments.Output.ToFileInfo();
fiImage.CreateParentDirectories();
string title = "# CREATE FOUR (4) SONOGRAMS FROM AUDIO RECORDING";
string date = "# DATE AND TIME: " + DateTime.Now;
LoggedConsole.WriteLine(title);
LoggedConsole.WriteLine(date);
LoggedConsole.WriteLine("# Input audio file: " + fiSourceRecording.Name);
LoggedConsole.WriteLine("# Output image file: " + fiImage);
//2. get the config dictionary
Config configuration = ConfigFile.Deserialize(fiConfig);
//below three lines are examples of retrieving info from Config config
//string analysisIdentifier = configuration[AnalysisKeys.AnalysisName];
//bool saveIntermediateWavFiles = (bool?)configuration[AnalysisKeys.SaveIntermediateWavFiles] ?? false;
//scoreThreshold = (double?)configuration[AnalysisKeys.EventThreshold] ?? scoreThreshold;
//3 transfer conogram parameters to a dictionary to be passed around
var configDict = new Dictionary <string, string>();
// #Resample rate must be 2 X the desired Nyquist. Default is that of recording.
configDict["ResampleRate"] = (configuration.GetIntOrNull(AnalysisKeys.ResampleRate) ?? 17640).ToString();
configDict["FrameLength"] = configuration[AnalysisKeys.FrameLength] ?? "512";
int frameSize = configuration.GetIntOrNull(AnalysisKeys.FrameLength) ?? 512;
// #Frame Overlap as fraction: default=0.0
configDict["FrameOverlap"] = configuration[AnalysisKeys.FrameOverlap] ?? "0.0";
double windowOverlap = configuration.GetDoubleOrNull(AnalysisKeys.FrameOverlap) ?? 0.0;
// #MinHz: 500
// #MaxHz: 3500
// #NOISE REDUCTION PARAMETERS
configDict["DoNoiseReduction"] = configuration["DoNoiseReduction"] ?? "true";
configDict["BgNoiseThreshold"] = configuration["BgNoiseThreshold"] ?? "3.0";
configDict["ADD_AXES"] = configuration["ADD_AXES"] ?? "true";
configDict["AddSegmentationTrack"] = configuration["AddSegmentationTrack"] ?? "true";
// 3: GET RECORDING
var startOffsetMins = TimeSpan.Zero;
var endOffsetMins = TimeSpan.Zero;
FileInfo fiOutputSegment = fiSourceRecording;
if (!(startOffsetMins == TimeSpan.Zero && endOffsetMins == TimeSpan.Zero))
{
var buffer = new TimeSpan(0, 0, 0);
fiOutputSegment = new FileInfo(Path.Combine(fiImage.DirectoryName, "tempWavFile.wav"));
//This method extracts segment and saves to disk at the location fiOutputSegment.
var resampleRate = configuration.GetIntOrNull(AnalysisKeys.ResampleRate) ?? AppConfigHelper.DefaultTargetSampleRate;
AudioRecording.ExtractSegment(fiSourceRecording, startOffsetMins, endOffsetMins, buffer, resampleRate, fiOutputSegment);
}
var recording = new AudioRecording(fiOutputSegment.FullName);
// EXTRACT ENVELOPE and SPECTROGRAM
var dspOutput = DSP_Frames.ExtractEnvelopeAndFfts(recording, frameSize, windowOverlap);
// average absolute value over the minute recording
////double[] avAbsolute = dspOutput.Average;
// (A) ################################## EXTRACT INDICES FROM THE SIGNAL WAVEFORM ##################################
// var wavDuration = TimeSpan.FromSeconds(recording.WavReader.Time.TotalSeconds);
// double totalSeconds = wavDuration.TotalSeconds;
// double[] signalEnvelope = dspOutput.Envelope;
// double avSignalEnvelope = signalEnvelope.Average();
// double[] frameEnergy = dspOutput.FrameEnergy;
// double highAmplIndex = dspOutput.HighAmplitudeCount / totalSeconds;
// double binWidth = dspOutput.BinWidth;
// int nyquistBin = dspOutput.NyquistBin;
// dspOutput.WindowPower,
// dspOutput.FreqBinWidth
int nyquistFreq = dspOutput.NyquistFreq;
double epsilon = recording.Epsilon;
// i: prepare amplitude spectrogram
double[,] amplitudeSpectrogramData = dspOutput.AmplitudeSpectrogram; // get amplitude spectrogram.
var image1 = ImageTools.DrawReversedMatrix(MatrixTools.MatrixRotate90Anticlockwise(amplitudeSpectrogramData));
// ii: prepare decibel spectrogram prior to noise removal
double[,] decibelSpectrogramdata = MFCCStuff.DecibelSpectra(dspOutput.AmplitudeSpectrogram, dspOutput.WindowPower, recording.SampleRate, epsilon);
decibelSpectrogramdata = MatrixTools.NormaliseMatrixValues(decibelSpectrogramdata);
var image2 = ImageTools.DrawReversedMatrix(MatrixTools.MatrixRotate90Anticlockwise(decibelSpectrogramdata));
// iii: Calculate background noise spectrum in decibels
// Calculate noise value for each freq bin.
double sdCount = 0.0; // number of SDs above the mean for noise removal
var decibelProfile = NoiseProfile.CalculateModalNoiseProfile(decibelSpectrogramdata, sdCount);
// DataTools.writeBarGraph(dBProfile.NoiseMode);
// iv: Prepare noise reduced spectrogram
decibelSpectrogramdata = SNR.TruncateBgNoiseFromSpectrogram(decibelSpectrogramdata, decibelProfile.NoiseThresholds);
//double dBThreshold = 1.0; // SPECTRAL dB THRESHOLD for smoothing background
//decibelSpectrogramdata = SNR.RemoveNeighbourhoodBackgroundNoise(decibelSpectrogramdata, dBThreshold);
var image3 = ImageTools.DrawReversedMatrix(MatrixTools.MatrixRotate90Anticlockwise(decibelSpectrogramdata));
// prepare new sonogram config and draw second image going down different code pathway
var config = new SonogramConfig
{
MinFreqBand = 0,
MaxFreqBand = 10000,
NoiseReductionType = SNR.KeyToNoiseReductionType("Standard"),
NoiseReductionParameter = 1.0,
WindowSize = frameSize,
WindowOverlap = windowOverlap,
};
//var mfccConfig = new MfccConfiguration(config);
int bandCount = config.mfccConfig.FilterbankCount;
bool doMelScale = config.mfccConfig.DoMelScale;
int ccCount = config.mfccConfig.CcCount;
int fftBins = config.FreqBinCount; //number of Hz bands = 2^N +1 because includes the DC band
int minHz = config.MinFreqBand ?? 0;
int maxHz = config.MaxFreqBand ?? nyquistFreq;
var standardSonogram = new SpectrogramStandard(config, recording.WavReader);
var image4 = standardSonogram.GetImage();
// TODO next line crashes - does not produce cepstral sonogram.
//SpectrogramCepstral cepSng = new SpectrogramCepstral(config, recording.WavReader);
//Image image5 = cepSng.GetImage();
//var mti = SpectrogramTools.Sonogram2MultiTrackImage(sonogram, configDict);
//var image = mti.GetImage();
//Image image = SpectrogramTools.Matrix2SonogramImage(deciBelSpectrogram, config);
//Image image = SpectrogramTools.Audio2SonogramImage(FileInfo fiAudio, Dictionary<string, string> configDict);
//prepare sonogram images
var protoImage6 = new Image_MultiTrack(standardSonogram.GetImage(doHighlightSubband: false, add1KHzLines: true, doMelScale: false));
protoImage6.AddTrack(ImageTrack.GetTimeTrack(standardSonogram.Duration, standardSonogram.FramesPerSecond));
protoImage6.AddTrack(ImageTrack.GetWavEnvelopeTrack(recording, protoImage6.SonogramImage.Width));
protoImage6.AddTrack(ImageTrack.GetSegmentationTrack(standardSonogram));
var image6 = protoImage6.GetImage();
var list = new List <Image <Rgb24> >();
list.Add(image1); // amplitude spectrogram
list.Add(image2); // decibel spectrogram before noise removal
list.Add(image3); // decibel spectrogram after noise removal
list.Add(image4); // second version of noise reduced spectrogram
//list.Add(image5); // ceptral sonogram
list.Add(image6.CloneAs <Rgb24>()); // multitrack image
Image finalImage = ImageTools.CombineImagesVertically(list);
finalImage.Save(fiImage.FullName);
////2: NOISE REMOVAL
//double[,] originalSg = sonogram.Data;
//double[,] mnr = sonogram.Data;
//mnr = ImageTools.WienerFilter(mnr, 3);
//double backgroundThreshold = 4.0; //SETS MIN DECIBEL BOUND
//var output = SNR.NoiseReduce(mnr, NoiseReductionType.STANDARD, backgroundThreshold);
//double ConfigRange = 70; //sets the the max dB
//mnr = SNR.SetConfigRange(output.Item1, 0.0, ConfigRange);
////3: Spectral tracks sonogram
//byte[,] binary = MatrixTools.IdentifySpectralRidges(mnr);
//binary = MatrixTools.ThresholdBinarySpectrum(binary, mnr, 10);
//binary = MatrixTools.RemoveOrphanOnesInBinaryMatrix(binary);
////binary = MatrixTools.PickOutLines(binary); //syntactic approach
//sonogram.SetBinarySpectrum(binary);
////sonogram.Data = SNR.SpectralRidges2Intensity(binary, originalSg);
//image = new Image_MultiTrack(sonogram.GetImage(doHighlightSubband, false));
//image.AddTrack(ImageTrack.GetTimeTrack(sonogram.Duration, sonogram.FramesPerSecond));
//image.AddTrack(ImageTrack.GetWavEnvelopeTrack(recording, image.sonogramImage.Width));
//image.AddTrack(ImageTrack.GetSegmentationTrack(sonogram));
//fn = outputFolder + wavFileName + "_tracks.png";
//image.Save(fn);
//LoggedConsole.WriteLine("Spectral tracks sonogram to file: " + fn);
//3: prepare image of spectral peaks sonogram
//sonogram.Data = SNR.NoiseReduce_Peaks(originalSg, dynamicRange);
//image = new Image_MultiTrack(sonogram.GetImage(doHighlightSubband, add1kHzLines));
//image.AddTrack(ImageTrack.GetTimeTrack(sonogram.Duration));
//image.AddTrack(ImageTrack.GetWavEnvelopeTrack(recording, image.Image.Width));
//image.AddTrack(ImageTrack.GetSegmentationTrack(sonogram));
//fn = outputFolder + wavFileName + "_peaks.png";
//image.Save(fn);
//LoggedConsole.WriteLine("Spectral peaks sonogram to file: " + fn);
//4: Sobel approach
//sonogram.Data = SNR.NoiseReduce_Sobel(originalSg, dynamicRange);
//image = new Image_MultiTrack(sonogram.GetImage(doHighlightSubband, add1kHzLines));
//image.AddTrack(ImageTrack.GetTimeTrack(sonogram.Duration));
//image.AddTrack(ImageTrack.GetWavEnvelopeTrack(recording, image.Image.Width));
//image.AddTrack(ImageTrack.GetSegmentationTrack(sonogram));
//fn = outputFolder + wavFileName + "_sobel.png";
//image.Save(fn);
//LoggedConsole.WriteLine("Sobel sonogram to file: " + fn);
// I1.txt contains the sonogram matrix produced by matlab
//string matlabFile = @"C:\SensorNetworks\Software\AudioAnalysis\AED\Test\matlab\GParrots_JB2_20090607-173000.wav_minute_3\I1.txt";
//double[,] matlabMatrix = Util.fileToMatrix(matlabFile, 256, 5166);
//LoggedConsole.WriteLine(matrix[0, 2] + " vs " + matlabMatrix[254, 0]);
//LoggedConsole.WriteLine(matrix[0, 3] + " vs " + matlabMatrix[253, 0]);
// TODO put this back once sonogram issues resolved
/*
* LoggedConsole.WriteLine("START: AED");
* IEnumerable<Oblong> oblongs = AcousticEventDetection.detectEvents(3.0, 100, matrix);
* LoggedConsole.WriteLine("END: AED");
*
*
* //set up static variables for init Acoustic events
* //AcousticEvent. doMelScale = config.DoMelScale;
* AcousticEvent.FreqBinCount = config.FreqBinCount;
* AcousticEvent.FreqBinWidth = config.FftConfig.NyquistFreq / (double)config.FreqBinCount;
* // int minF = (int)config.MinFreqBand;
* // int maxF = (int)config.MaxFreqBand;
* AcousticEvent.FrameDuration = config.GetFrameOffset();
*
*
* var events = new List<EventPatternRecog.Rectangle>();
* foreach (Oblong o in oblongs)
* {
* var e = new AcousticEvent(o);
* events.Add(new EventPatternRecog.Rectangle(e.StartTime, (double) e.MaxFreq, e.StartTime + e.Duration, (double)e.MinFreq));
* //LoggedConsole.WriteLine(e.StartTime + "," + e.Duration + "," + e.MinFreq + "," + e.MaxFreq);
* }
*
* LoggedConsole.WriteLine("# AED events: " + events.Count);
*
* LoggedConsole.WriteLine("START: EPR");
* IEnumerable<EventPatternRecog.Rectangle> eprRects = EventPatternRecog.detectGroundParrots(events);
* LoggedConsole.WriteLine("END: EPR");
*
* var eprEvents = new List<AcousticEvent>();
* foreach (EventPatternRecog.Rectangle r in eprRects)
* {
* var ae = new AcousticEvent(r.Left, r.Right - r.Left, r.Bottom, r.Top, false);
* LoggedConsole.WriteLine(ae.WriteProperties());
* eprEvents.Add(ae);
* }
*
* string imagePath = Path.Combine(outputFolder, "RESULTS_" + Path.GetFileNameWithoutExtension(recording.BaseName) + ".png");
*
* bool doHighlightSubband = false; bool add1kHzLines = true;
* var image = new Image_MultiTrack(sonogram.GetImage(doHighlightSubband, add1kHzLines));
* //image.AddTrack(ImageTrack.GetTimeTrack(sonogram.Duration));
* //image.AddTrack(ImageTrack.GetWavEnvelopeTrack(recording, image.Image.Width));
* //image.AddTrack(ImageTrack.GetSegmentationTrack(sonogram));
* image.AddEvents(eprEvents);
* image.Save(outputFolder + wavFileName + ".png");
*/
LoggedConsole.WriteLine("\nFINISHED!");
}
public static void Execute(Arguments arguments)
{
const string Title = "# DETERMINING SIGNAL TO NOISE RATIO IN RECORDING";
string date = "# DATE AND TIME: " + DateTime.Now;
Log.WriteLine(Title);
Log.WriteLine(date);
Log.Verbosity = 1;
var input = arguments.Source;
var sourceFileName = input.Name;
var outputDir = arguments.Output;
var fileNameWithoutExtension = Path.GetFileNameWithoutExtension(input.FullName);
var outputTxtPath = Path.Combine(outputDir.FullName, fileNameWithoutExtension + ".txt").ToFileInfo();
Log.WriteIfVerbose("# Recording file: " + input.FullName);
Log.WriteIfVerbose("# Config file: " + arguments.Config);
Log.WriteIfVerbose("# Output folder =" + outputDir.FullName);
FileTools.WriteTextFile(outputTxtPath.FullName, date + "\n# Recording file: " + input.FullName);
//READ PARAMETER VALUES FROM INI FILE
// load YAML configuration
Config configuration = ConfigFile.Deserialize(arguments.Config);
//ii: SET SONOGRAM CONFIGURATION
SonogramConfig sonoConfig = new SonogramConfig(); //default values config
sonoConfig.SourceFName = input.FullName;
sonoConfig.WindowSize = configuration.GetIntOrNull(AnalysisKeys.KeyFrameSize) ?? 512;
sonoConfig.WindowOverlap = configuration.GetDoubleOrNull(AnalysisKeys.FrameOverlap) ?? 0.5;
sonoConfig.WindowFunction = configuration[AnalysisKeys.KeyWindowFunction];
sonoConfig.NPointSmoothFFT = configuration.GetIntOrNull(AnalysisKeys.KeyNPointSmoothFft) ?? 256;
sonoConfig.NoiseReductionType = SNR.KeyToNoiseReductionType(configuration[AnalysisKeys.NoiseReductionType]);
int minHz = configuration.GetIntOrNull("MIN_HZ") ?? 0;
int maxHz = configuration.GetIntOrNull("MAX_HZ") ?? 11050;
double segK1 = configuration.GetDoubleOrNull("SEGMENTATION_THRESHOLD_K1") ?? 0;
double segK2 = configuration.GetDoubleOrNull("SEGMENTATION_THRESHOLD_K2") ?? 0;
double latency = configuration.GetDoubleOrNull("K1_K2_LATENCY") ?? 0;
double vocalGap = configuration.GetDoubleOrNull("VOCAL_GAP") ?? 0;
double minVocalLength = configuration.GetDoubleOrNull("MIN_VOCAL_DURATION") ?? 0;
//bool DRAW_SONOGRAMS = (bool?)configuration.DrawSonograms ?? true; //options to draw sonogram
//double intensityThreshold = Acoustics.AED.Default.intensityThreshold;
//if (dict.ContainsKey(key_AED_INTENSITY_THRESHOLD)) intensityThreshold = Double.Parse(dict[key_AED_INTENSITY_THRESHOLD]);
//int smallAreaThreshold = Acoustics.AED.Default.smallAreaThreshold;
//if( dict.ContainsKey(key_AED_SMALL_AREA_THRESHOLD)) smallAreaThreshold = Int32.Parse(dict[key_AED_SMALL_AREA_THRESHOLD]);
// COnvert input recording into wav
var convertParameters = new AudioUtilityRequest {
TargetSampleRate = 17640
};
var fileToAnalyse = new FileInfo(Path.Combine(outputDir.FullName, "temp.wav"));
if (File.Exists(fileToAnalyse.FullName))
{
File.Delete(fileToAnalyse.FullName);
}
var convertedFileInfo = AudioFilePreparer.PrepareFile(
input,
fileToAnalyse,
convertParameters,
outputDir);
// (A) ##########################################################################################################################
AudioRecording recording = new AudioRecording(fileToAnalyse.FullName);
int signalLength = recording.WavReader.Samples.Length;
TimeSpan wavDuration = TimeSpan.FromSeconds(recording.WavReader.Time.TotalSeconds);
double frameDurationInSeconds = sonoConfig.WindowSize / (double)recording.SampleRate;
TimeSpan frameDuration = TimeSpan.FromTicks((long)(frameDurationInSeconds * TimeSpan.TicksPerSecond));
int stepSize = (int)Math.Floor(sonoConfig.WindowSize * (1 - sonoConfig.WindowOverlap));
double stepDurationInSeconds = sonoConfig.WindowSize * (1 - sonoConfig.WindowOverlap)
/ recording.SampleRate;
TimeSpan stepDuration = TimeSpan.FromTicks((long)(stepDurationInSeconds * TimeSpan.TicksPerSecond));
double framesPerSecond = 1 / stepDuration.TotalSeconds;
int frameCount = signalLength / stepSize;
// (B) ################################## EXTRACT ENVELOPE and SPECTROGRAM ##################################
var dspOutput = DSP_Frames.ExtractEnvelopeAndFfts(
recording,
sonoConfig.WindowSize,
sonoConfig.WindowOverlap);
//double[] avAbsolute = dspOutput.Average; //average absolute value over the minute recording
// (C) ################################## GET SIGNAL WAVEFORM ##################################
double[] signalEnvelope = dspOutput.Envelope;
double avSignalEnvelope = signalEnvelope.Average();
// (D) ################################## GET Amplitude Spectrogram ##################################
double[,] amplitudeSpectrogram = dspOutput.AmplitudeSpectrogram; // get amplitude spectrogram.
// (E) ################################## Generate deciBel spectrogram from amplitude spectrogram
double epsilon = Math.Pow(0.5, recording.BitsPerSample - 1);
double[,] deciBelSpectrogram = MFCCStuff.DecibelSpectra(
dspOutput.AmplitudeSpectrogram,
dspOutput.WindowPower,
recording.SampleRate,
epsilon);
LoggedConsole.WriteLine("# Finished calculating decibel spectrogram.");
StringBuilder sb = new StringBuilder();
sb.AppendLine("\nSIGNAL PARAMETERS");
sb.AppendLine("Signal Duration =" + wavDuration);
sb.AppendLine("Sample Rate =" + recording.SampleRate);
sb.AppendLine("Min Signal Value =" + dspOutput.MinSignalValue);
sb.AppendLine("Max Signal Value =" + dspOutput.MaxSignalValue);
sb.AppendLine("Max Absolute Ampl =" + signalEnvelope.Max().ToString("F3") + " (See Note 1)");
sb.AppendLine("Epsilon Ampl (1 bit)=" + epsilon);
sb.AppendLine("\nFRAME PARAMETERS");
sb.AppendLine("Window Size =" + sonoConfig.WindowSize);
sb.AppendLine("Frame Count =" + frameCount);
sb.AppendLine("Envelope length=" + signalEnvelope.Length);
sb.AppendLine("Frame Duration =" + frameDuration.TotalMilliseconds.ToString("F3") + " ms");
sb.AppendLine("Frame overlap =" + sonoConfig.WindowOverlap);
sb.AppendLine("Step Size =" + stepSize);
sb.AppendLine("Step duration =" + stepDuration.TotalMilliseconds.ToString("F3") + " ms");
sb.AppendLine("Frames Per Sec =" + framesPerSecond.ToString("F1"));
sb.AppendLine("\nFREQUENCY PARAMETERS");
sb.AppendLine("Nyquist Freq =" + dspOutput.NyquistFreq + " Hz");
sb.AppendLine("Freq Bin Width =" + dspOutput.FreqBinWidth.ToString("F2") + " Hz");
sb.AppendLine("Nyquist Bin =" + dspOutput.NyquistBin);
sb.AppendLine("\nENERGY PARAMETERS");
double val = dspOutput.FrameEnergy.Min();
sb.AppendLine(
"Minimum dB / frame =" + (10 * Math.Log10(val)).ToString("F2") + " (See Notes 2, 3 & 4)");
val = dspOutput.FrameEnergy.Max();
sb.AppendLine("Maximum dB / frame =" + (10 * Math.Log10(val)).ToString("F2"));
sb.AppendLine("\ndB NOISE SUBTRACTION");
double noiseRange = 2.0;
//sb.AppendLine("Noise (estimate of mode) =" + sonogram.SnrData.NoiseSubtracted.ToString("F3") + " dB (See Note 5)");
//double noiseSpan = sonogram.SnrData.NoiseRange;
//sb.AppendLine("Noise range =" + noiseSpan.ToString("F2") + " to +" + (noiseSpan * -1).ToString("F2") + " dB (See Note 6)");
//sb.AppendLine("SNR (max frame-noise) =" + sonogram.SnrData.Snr.ToString("F2") + " dB (See Note 7)");
//sb.Append("\nSEGMENTATION PARAMETERS");
//sb.Append("Segment Thresholds K1: {0:f2}. K2: {1:f2} (See Note 8)", segK1, segK2);
//sb.Append("# Event Count = " + predictedEvents.Count());
FileTools.Append2TextFile(outputTxtPath.FullName, sb.ToString());
FileTools.Append2TextFile(outputTxtPath.FullName, GetSNRNotes(noiseRange).ToString());
// (F) ################################## DRAW IMAGE 1: original spectorgram
Log.WriteLine("# Start drawing noise reduced sonograms.");
TimeSpan X_AxisInterval = TimeSpan.FromSeconds(1);
//int Y_AxisInterval = (int)Math.Round(1000 / dspOutput.FreqBinWidth);
int nyquist = recording.SampleRate / 2;
int hzInterval = 1000;
var image1 = DrawSonogram(deciBelSpectrogram, wavDuration, X_AxisInterval, stepDuration, nyquist, hzInterval);
// (G) ################################## Calculate modal background noise spectrum in decibels
//double SD_COUNT = -0.5; // number of SDs above the mean for noise removal
//NoiseReductionType nrt = NoiseReductionType.MODAL;
//System.Tuple<double[,], double[]> tuple = SNR.NoiseReduce(deciBelSpectrogram, nrt, SD_COUNT);
//double upperPercentileBound = 0.2; // lowest percentile for noise removal
//NoiseReductionType nrt = NoiseReductionType.LOWEST_PERCENTILE;
//System.Tuple<double[,], double[]> tuple = SNR.NoiseReduce(deciBelSpectrogram, nrt, upperPercentileBound);
// (H) ################################## Calculate BRIGGS noise removal from amplitude spectrum
int percentileBound = 20; // low energy percentile for noise removal
//double binaryThreshold = 0.6; //works for higher SNR recordings
double binaryThreshold = 0.4; //works for lower SNR recordings
//double binaryThreshold = 0.3; //works for lower SNR recordings
double[,] m = NoiseRemoval_Briggs.BriggsNoiseFilterAndGetMask(
amplitudeSpectrogram,
percentileBound,
binaryThreshold);
string title = "TITLE";
var image2 = NoiseRemoval_Briggs.DrawSonogram(
m,
wavDuration,
X_AxisInterval,
stepDuration,
nyquist, hzInterval,
title);
//Image image2 = NoiseRemoval_Briggs.BriggsNoiseFilterAndGetSonograms(amplitudeSpectrogram, upperPercentileBound, binaryThreshold,
// wavDuration, X_AxisInterval, stepDuration, Y_AxisInterval);
// (I) ################################## Calculate MEDIAN noise removal from amplitude spectrum
//double upperPercentileBound = 0.8; // lowest percentile for noise removal
//NoiseReductionType nrt = NoiseReductionType.MEDIAN;
//System.Tuple<double[,], double[]> tuple = SNR.NoiseReduce(deciBelSpectrogram, nrt, upperPercentileBound);
//double[,] noiseReducedSpectrogram1 = tuple.Item1; //
//double[] noiseProfile = tuple.Item2; // smoothed modal profile
//SNR.NoiseProfile dBProfile = SNR.CalculateNoiseProfile(deciBelSpectrogram, SD_COUNT); // calculate noise value for each freq bin.
//double[] noiseProfile = DataTools.filterMovingAverage(dBProfile.noiseThresholds, 7); // smooth modal profile
//double[,] noiseReducedSpectrogram1 = SNR.TruncateBgNoiseFromSpectrogram(deciBelSpectrogram, dBProfile.noiseThresholds);
//Image image2 = DrawSonogram(noiseReducedSpectrogram1, wavDuration, X_AxisInterval, stepDuration, Y_AxisInterval);
var combinedImage = ImageTools.CombineImagesVertically(image1, image2);
string imagePath = Path.Combine(outputDir.FullName, fileNameWithoutExtension + ".png");
combinedImage.Save(imagePath);
// (G) ################################## Calculate modal background noise spectrum in decibels
Log.WriteLine("# Finished recording:- " + input.Name);
}
public static IndexCalculateResult Analysis(
AudioRecording recording,
TimeSpan subsegmentOffsetTimeSpan,
Dictionary <string, IndexProperties> indexProperties,
int sampleRateOfOriginalAudioFile,
TimeSpan segmentStartOffset,
IndexCalculateConfig config,
bool returnSonogramInfo = false)
{
// returnSonogramInfo = true; // if debugging
double epsilon = recording.Epsilon;
int signalLength = recording.WavReader.GetChannel(0).Length;
int sampleRate = recording.WavReader.SampleRate;
var segmentDuration = TimeSpan.FromSeconds(recording.WavReader.Time.TotalSeconds);
var indexCalculationDuration = config.IndexCalculationDurationTimeSpan;
int nyquist = sampleRate / 2;
// Get FRAME parameters for the calculation of Acoustic Indices
//WARNING: DO NOT USE Frame Overlap when calculating acoustic indices.
// It yields ACI, BGN, POW and EVN results that are significantly different from the default.
// I have not had time to check if the difference is meaningful. Best to avoid.
//int frameSize = (int?)config[AnalysisKeys.FrameLength] ?? IndexCalculateConfig.DefaultWindowSize;
int frameSize = config.FrameLength;
int frameStep = frameSize; // that is, windowOverlap = zero
double frameStepDuration = frameStep / (double)sampleRate; // fraction of a second
var frameStepTimeSpan = TimeSpan.FromTicks((long)(frameStepDuration * TimeSpan.TicksPerSecond));
int midFreqBound = config.MidFreqBound;
int lowFreqBound = config.LowFreqBound;
int freqBinCount = frameSize / 2;
// double freqBinWidth = recording.Nyquist / (double)freqBinCount;
// get duration in seconds and sample count and frame count
double subsegmentDurationInSeconds = indexCalculationDuration.TotalSeconds;
int subsegmentSampleCount = (int)(subsegmentDurationInSeconds * sampleRate);
double subsegmentFrameCount = subsegmentSampleCount / (double)frameStep;
subsegmentFrameCount = (int)Math.Ceiling(subsegmentFrameCount);
// In order not to lose the last fractional frame, round up the frame number
// and get the exact number of samples in the integer number of frames.
// Do this because when IndexCalculationDuration = 100ms, the number of frames is only 8.
subsegmentSampleCount = (int)(subsegmentFrameCount * frameStep);
// get start and end samples of the subsegment and noise segment
double localOffsetInSeconds = subsegmentOffsetTimeSpan.TotalSeconds - segmentStartOffset.TotalSeconds;
int startSample = (int)(localOffsetInSeconds * sampleRate);
int endSample = startSample + subsegmentSampleCount - 1;
// Default behaviour: set SUBSEGMENT = total recording
var subsegmentRecording = recording;
// But if the indexCalculationDuration < segmentDuration
if (indexCalculationDuration < segmentDuration)
{
// minimum samples needed to calculate acoustic indices. This value was chosen somewhat arbitrarily.
// It allowes for case where IndexCalculationDuration = 100ms which is approx 8 frames
int minimumViableSampleCount = frameSize * 8;
int availableSignal = signalLength - startSample;
// if (the required audio is beyond recording OR insufficient for analysis) then backtrack.
if (availableSignal < minimumViableSampleCount)
{
// Back-track so we can fill a whole result.
// This is a silent correction, equivalent to having a segment overlap for the last segment.
var oldStart = startSample;
startSample = signalLength - subsegmentSampleCount;
endSample = signalLength;
Logger.Trace(" Backtrack subsegment to fill missing data from imperfect audio cuts because not enough samples available. " + (oldStart - startSample) + " samples overlap.");
}
var subsamples = DataTools.Subarray(recording.WavReader.Samples, startSample, subsegmentSampleCount);
var wr = new Acoustics.Tools.Wav.WavReader(subsamples, 1, 16, sampleRate);
subsegmentRecording = new AudioRecording(wr);
}
// INITIALISE a RESULTS STRUCTURE TO return
// initialize a result object in which to store SummaryIndexValues and SpectralIndexValues etc.
var result = new IndexCalculateResult(freqBinCount, indexProperties, indexCalculationDuration, subsegmentOffsetTimeSpan, config);
SummaryIndexValues summaryIndices = result.SummaryIndexValues;
SpectralIndexValues spectralIndices = result.SpectralIndexValues;
// set up default spectrogram to return
result.Sg = returnSonogramInfo ? GetSonogram(recording, windowSize: 1024) : null;
result.Hits = null;
result.TrackScores = new List <Plot>();
// ################################## FINSIHED SET-UP
// ################################## NOW GET THE AMPLITUDE SPECTORGRAMS
// EXTRACT ENVELOPE and SPECTROGRAM FROM SUBSEGMENT
var dspOutput1 = DSP_Frames.ExtractEnvelopeAndFfts(subsegmentRecording, frameSize, frameStep);
// Select band according to min and max bandwidth
int minBand = (int)(dspOutput1.AmplitudeSpectrogram.GetLength(1) * config.MinBandWidth);
int maxBand = (int)(dspOutput1.AmplitudeSpectrogram.GetLength(1) * config.MaxBandWidth) - 1;
dspOutput1.AmplitudeSpectrogram = MatrixTools.Submatrix(
dspOutput1.AmplitudeSpectrogram,
0,
minBand,
dspOutput1.AmplitudeSpectrogram.GetLength(0) - 1,
maxBand);
// TODO: Michael to review whether bandwidth filter should be moved to DSP_Frames??
// Recalculate NyquistBin and FreqBinWidth, because they change with band selection
//dspOutput1.NyquistBin = dspOutput1.AmplitudeSpectrogram.GetLength(1) - 1;
//dspOutput1.FreqBinWidth = sampleRate / (double)dspOutput1.AmplitudeSpectrogram.GetLength(1) / 2;
// Linear or Octave or Mel frequency scale? Set Linear as default.
var freqScale = new FrequencyScale(nyquist: nyquist, frameSize: frameSize, hertzGridInterval: 1000);
var freqScaleType = config.FrequencyScale;
bool octaveScale = freqScaleType == FreqScaleType.Linear125Octaves7Tones28Nyquist32000;
bool melScale = freqScaleType == FreqScaleType.Mel;
if (octaveScale)
{
// only allow one octave scale at the moment - for Jasco marine recordings.
// ASSUME fixed Occtave scale - USEFUL ONLY FOR JASCO 64000sr MARINE RECORDINGS
// If you wish to use other octave scale types then need to put in the config file and and set up recovery here.
freqScale = new FrequencyScale(FreqScaleType.Linear125Octaves7Tones28Nyquist32000);
// Recalculate the spectrogram according to octave scale. This option works only when have high SR recordings.
dspOutput1.AmplitudeSpectrogram = OctaveFreqScale.AmplitudeSpectra(
dspOutput1.AmplitudeSpectrogram,
dspOutput1.WindowPower,
sampleRate,
epsilon,
freqScale);
dspOutput1.NyquistBin = dspOutput1.AmplitudeSpectrogram.GetLength(1) - 1; // ASSUMPTION!!! Nyquist is in top Octave bin - not necessarily true!!
}
else if (melScale)
{
int minFreq = 0;
int maxFreq = recording.Nyquist;
dspOutput1.AmplitudeSpectrogram = MFCCStuff.MelFilterBank(
dspOutput1.AmplitudeSpectrogram,
config.MelScale,
recording.Nyquist,
minFreq,
maxFreq);
dspOutput1.NyquistBin = dspOutput1.AmplitudeSpectrogram.GetLength(1) - 1;
// TODO: This doesn't make any sense, since the frequency width changes for each bin. Probably need to set this to NaN.
// TODO: Whatever uses this value below, should probably be changed to not be depending on it.
dspOutput1.FreqBinWidth = sampleRate / (double)dspOutput1.AmplitudeSpectrogram.GetLength(1) / 2;
}
// NOW EXTRACT SIGNAL FOR BACKGROUND NOISE CALCULATION
// If the index calculation duration >= 30 seconds, then calculate BGN from the existing segment of recording.
bool doSeparateBgnNoiseCalculation = indexCalculationDuration.TotalSeconds + (2 * config.BgNoiseBuffer.TotalSeconds) < segmentDuration.TotalSeconds / 2;
var dspOutput2 = dspOutput1;
if (doSeparateBgnNoiseCalculation)
{
// GET a longer SUBSEGMENT FOR NOISE calculation with 5 sec buffer on either side.
// If the index calculation duration is shorter than 30 seconds, then need to calculate BGN noise from a longer length of recording
// i.e. need to add noiseBuffer either side. Typical noiseBuffer value = 5 seconds
int sampleBuffer = (int)(config.BgNoiseBuffer.TotalSeconds * sampleRate);
var bgnRecording = AudioRecording.GetRecordingSubsegment(recording, startSample, endSample, sampleBuffer);
// EXTRACT ENVELOPE and SPECTROGRAM FROM BACKGROUND NOISE SUBSEGMENT
dspOutput2 = DSP_Frames.ExtractEnvelopeAndFfts(bgnRecording, frameSize, frameStep);
// If necessary, recalculate the spectrogram according to octave scale. This option works only when have high SR recordings.
if (octaveScale)
{
// ASSUME fixed Occtave scale - USEFUL ONLY FOR JASCO 64000sr MARINE RECORDINGS
// If you wish to use other octave scale types then need to put in the config file and and set up recovery here.
dspOutput2.AmplitudeSpectrogram = OctaveFreqScale.AmplitudeSpectra(
dspOutput2.AmplitudeSpectrogram,
dspOutput2.WindowPower,
sampleRate,
epsilon,
freqScale);
dspOutput2.NyquistBin = dspOutput2.AmplitudeSpectrogram.GetLength(1) - 1; // ASSUMPTION!!! Nyquist is in top Octave bin - not necessarily true!!
}
}
// ###################################### BEGIN CALCULATION OF INDICES ##################################
// (A) ################################## EXTRACT SUMMARY INDICES FROM THE SIGNAL WAVEFORM ##################################
// average absolute value over the minute recording - not useful
// double[] avAbsolute = dspOutput1.Average;
double[] signalEnvelope = dspOutput1.Envelope;
double avgSignalEnvelope = signalEnvelope.Average();
// 10 times log of amplitude squared
summaryIndices.AvgSignalAmplitude = 20 * Math.Log10(avgSignalEnvelope);
// Deal with case where the signal waveform is continuous flat with values < 0.001. Has happened!!
// Although signal appears zero, this condition is required.
if (avgSignalEnvelope < 0.0001)
{
Logger.Debug("Segment skipped because avSignalEnvelope is < 0.001!");
summaryIndices.ZeroSignal = 1.0;
return(result);
}
// i. Check for clipping and high amplitude rates per second
summaryIndices.HighAmplitudeIndex = dspOutput1.HighAmplitudeCount / subsegmentDurationInSeconds;
summaryIndices.ClippingIndex = dspOutput1.ClipCount / subsegmentDurationInSeconds;
// ii. Calculate bg noise in dB
// Convert signal envelope to dB and subtract background noise. Default noise SD to calculate threshold = ZERO
double signalBgn = NoiseRemovalModal.CalculateBackgroundNoise(dspOutput2.Envelope);
summaryIndices.BackgroundNoise = signalBgn;
// iii: FRAME ENERGIES - convert signal to decibels and subtract background noise.
double[] dBEnvelope = SNR.Signal2Decibels(dspOutput1.Envelope);
double[] dBEnvelopeSansNoise = SNR.SubtractAndTruncate2Zero(dBEnvelope, signalBgn);
// iv: ACTIVITY for NOISE REDUCED SIGNAL ENVELOPE
// Calculate fraction of frames having acoustic activity
var activity = ActivityAndCover.CalculateActivity(dBEnvelopeSansNoise, frameStepTimeSpan);
summaryIndices.Activity = activity.FractionOfActiveFrames;
// v. average number of events per second whose duration > one frame
// average event duration in milliseconds - no longer calculated
//summaryIndices.AvgEventDuration = activity.avEventDuration;
summaryIndices.EventsPerSecond = activity.EventCount / subsegmentDurationInSeconds;
// vi. Calculate SNR and active frames SNR
summaryIndices.Snr = dBEnvelopeSansNoise.Max();
summaryIndices.AvgSnrOfActiveFrames = activity.ActiveAvDb;
// vii. ENTROPY of ENERGY ENVELOPE -- 1-Ht because want measure of concentration of acoustic energy.
double entropy = DataTools.EntropyNormalised(DataTools.SquareValues(signalEnvelope));
summaryIndices.TemporalEntropy = 1 - entropy;
// Note that the spectrogram has had the DC bin removed. i.e. has only 256 columns.
double[,] amplitudeSpectrogram = dspOutput1.AmplitudeSpectrogram; // get amplitude spectrogram.
// CALCULATE various NDSI (Normalised difference soundscape Index) FROM THE AMPLITUDE SPECTROGRAM
// These options proved to be highly correlated. Therefore only use tuple.Item 1 which derived from Power Spectral Density.
var tuple3 = SpectrogramTools.CalculateAvgSpectrumAndVarianceSpectrumFromAmplitudeSpectrogram(amplitudeSpectrogram);
summaryIndices.Ndsi = SpectrogramTools.CalculateNdsi(tuple3.Item1, sampleRate, 1000, 2000, 8000);
// (B) ################################## EXTRACT OSC SPECTRAL INDEX DIRECTLY FROM THE RECORDING ##################################
// Get the oscillation spectral index OSC separately from signal because need a different frame size etc.
var sampleLength = Oscillations2014.DefaultSampleLength;
var frameLength = Oscillations2014.DefaultFrameLength;
var sensitivity = Oscillations2014.DefaultSensitivityThreshold;
var spectralIndexShort = Oscillations2014.GetSpectralIndex_Osc(subsegmentRecording, frameLength, sampleLength, sensitivity);
// double length of the vector because want to work with 256 element vector for LDFC purposes
spectralIndices.OSC = DataTools.VectorDoubleLengthByAverageInterpolation(spectralIndexShort);
// (C) ################################## EXTRACT SPECTRAL INDICES FROM THE AMPLITUDE SPECTROGRAM ##################################
// i: CALCULATE SPECTRUM OF THE SUM OF FREQ BIN AMPLITUDES - used for later calculation of ACI
spectralIndices.SUM = MatrixTools.SumColumns(amplitudeSpectrogram);
// Calculate lower and upper boundary bin ids.
// Boundary between low & mid frequency bands is to avoid low freq bins containing anthropogenic noise. These biased index values away from biophony.
// Boundary of upper bird-band is to avoid high freq artefacts due to mp3.
int lowerBinBound = (int)Math.Ceiling(lowFreqBound / dspOutput1.FreqBinWidth);
int middleBinBound = (int)Math.Ceiling(midFreqBound / dspOutput1.FreqBinWidth);
// calculate number of freq bins in the bird-band.
int midBandBinCount = middleBinBound - lowerBinBound + 1;
if (octaveScale)
{
// the above frequency bin bounds do not apply with octave scale. Need to recalculate them suitable for Octave scale recording.
lowFreqBound = freqScale.LinearBound;
lowerBinBound = freqScale.GetBinIdForHerzValue(lowFreqBound);
midFreqBound = 8000; // This value appears suitable for Jasco Marine recordings. Not much happens above 8kHz.
//middleBinBound = freqScale.GetBinIdForHerzValue(midFreqBound);
middleBinBound = freqScale.GetBinIdInReducedSpectrogramForHerzValue(midFreqBound);
midBandBinCount = middleBinBound - lowerBinBound + 1;
}
// IFF there has been UP-SAMPLING, calculate bin of the original audio nyquist. this will be less than SR/2.
// original sample rate can be anything 11.0-44.1 kHz.
int originalNyquist = sampleRateOfOriginalAudioFile / 2;
// if upsampling has been done
if (dspOutput1.NyquistFreq > originalNyquist)
{
dspOutput1.NyquistFreq = originalNyquist;
dspOutput1.NyquistBin = (int)Math.Floor(originalNyquist / dspOutput1.FreqBinWidth); // note that binwidth does not change
}
// ii: CALCULATE THE ACOUSTIC COMPLEXITY INDEX
spectralIndices.DIF = AcousticComplexityIndex.SumOfAmplitudeDifferences(amplitudeSpectrogram);
double[] aciSpectrum = AcousticComplexityIndex.CalculateAci(amplitudeSpectrogram);
spectralIndices.ACI = aciSpectrum;
// remove low freq band of ACI spectrum and store average ACI value
double[] reducedAciSpectrum = DataTools.Subarray(aciSpectrum, lowerBinBound, midBandBinCount);
summaryIndices.AcousticComplexity = reducedAciSpectrum.Average();
// iii: CALCULATE the H(t) or Temporal ENTROPY Spectrum and then reverse the values i.e. calculate 1-Ht for energy concentration
double[] temporalEntropySpectrum = AcousticEntropy.CalculateTemporalEntropySpectrum(amplitudeSpectrogram);
for (int i = 0; i < temporalEntropySpectrum.Length; i++)
{
temporalEntropySpectrum[i] = 1 - temporalEntropySpectrum[i];
}
spectralIndices.ENT = temporalEntropySpectrum;
// iv: remove background noise from the amplitude spectrogram
// First calculate the noise profile from the amplitude sepctrogram
double[] spectralAmplitudeBgn = NoiseProfile.CalculateBackgroundNoise(dspOutput2.AmplitudeSpectrogram);
amplitudeSpectrogram = SNR.TruncateBgNoiseFromSpectrogram(amplitudeSpectrogram, spectralAmplitudeBgn);
// AMPLITUDE THRESHOLD for smoothing background, nhThreshold, assumes background noise ranges around -40dB.
// This value corresponds to approximately 6dB above backgorund.
amplitudeSpectrogram = SNR.RemoveNeighbourhoodBackgroundNoise(amplitudeSpectrogram, nhThreshold: 0.015);
////ImageTools.DrawMatrix(spectrogramData, @"C:\SensorNetworks\WavFiles\Crows\image.png", false);
////DataTools.writeBarGraph(modalValues);
result.AmplitudeSpectrogram = amplitudeSpectrogram;
// v: ENTROPY OF AVERAGE SPECTRUM & VARIANCE SPECTRUM - at this point the spectrogram is a noise reduced amplitude spectrogram
var tuple = AcousticEntropy.CalculateSpectralEntropies(amplitudeSpectrogram, lowerBinBound, midBandBinCount);
// ENTROPY of spectral averages - Reverse the values i.e. calculate 1-Hs and 1-Hv, and 1-Hcov for energy concentration
summaryIndices.EntropyOfAverageSpectrum = 1 - tuple.Item1;
// ENTROPY of spectrum of Variance values
summaryIndices.EntropyOfVarianceSpectrum = 1 - tuple.Item2;
// ENTROPY of spectrum of Coefficient of Variation values
summaryIndices.EntropyOfCoVSpectrum = 1 - tuple.Item3;
// vi: ENTROPY OF DISTRIBUTION of maximum SPECTRAL PEAKS.
// First extract High band SPECTROGRAM which is now noise reduced
double entropyOfPeaksSpectrum = AcousticEntropy.CalculateEntropyOfSpectralPeaks(amplitudeSpectrogram, lowerBinBound, middleBinBound);
summaryIndices.EntropyOfPeaksSpectrum = 1 - entropyOfPeaksSpectrum;
// ######################################################################################################################################################
// (C) ################################## EXTRACT SPECTRAL INDICES FROM THE DECIBEL SPECTROGRAM ##################################
// i: Convert amplitude spectrogram to deciBels and calculate the dB background noise profile
double[,] deciBelSpectrogram = MFCCStuff.DecibelSpectra(dspOutput2.AmplitudeSpectrogram, dspOutput2.WindowPower, sampleRate, epsilon);
double[] spectralDecibelBgn = NoiseProfile.CalculateBackgroundNoise(deciBelSpectrogram);
spectralIndices.BGN = spectralDecibelBgn;
// ii: Calculate the noise reduced decibel spectrogram derived from segment recording.
// REUSE the var decibelSpectrogram but this time using dspOutput1.
deciBelSpectrogram = MFCCStuff.DecibelSpectra(dspOutput1.AmplitudeSpectrogram, dspOutput1.WindowPower, sampleRate, epsilon);
deciBelSpectrogram = SNR.TruncateBgNoiseFromSpectrogram(deciBelSpectrogram, spectralDecibelBgn);
deciBelSpectrogram = SNR.RemoveNeighbourhoodBackgroundNoise(deciBelSpectrogram, nhThreshold: 2.0);
// iii: CALCULATE noise reduced AVERAGE DECIBEL SPECTRUM
spectralIndices.PMN = SpectrogramTools.CalculateAvgDecibelSpectrumFromDecibelSpectrogram(deciBelSpectrogram);
// iv: CALCULATE SPECTRAL COVER.
// NOTE: at this point, decibelSpectrogram is noise reduced. All values >= 0.0
// FreqBinWidth can be accessed, if required, through dspOutput1.FreqBinWidth
double dBThreshold = ActivityAndCover.DefaultActivityThresholdDb; // dB THRESHOLD for calculating spectral coverage
var spActivity = ActivityAndCover.CalculateSpectralEvents(deciBelSpectrogram, dBThreshold, frameStepTimeSpan, lowerBinBound, middleBinBound);
spectralIndices.CVR = spActivity.CoverSpectrum;
spectralIndices.EVN = spActivity.EventSpectrum;
summaryIndices.HighFreqCover = spActivity.HighFreqBandCover;
summaryIndices.MidFreqCover = spActivity.MidFreqBandCover;
summaryIndices.LowFreqCover = spActivity.LowFreqBandCover;
// ######################################################################################################################################################
// v: CALCULATE SPECTRAL PEAK TRACKS and RIDGE indices.
// NOTE: at this point, the var decibelSpectrogram is noise reduced. i.e. all its values >= 0.0
// Detecting ridges or spectral peak tracks requires using a 5x5 mask which has edge effects.
// This becomes significant if we have a short indexCalculationDuration.
// Consequently if the indexCalculationDuration < 10 seconds then we revert back to the recording and cut out a recording segment that includes
// a buffer for edge effects. In most cases however, we can just use the decibel spectrogram already calculated and ignore the edge effects.
double peakThreshold = 6.0; //dB
SpectralPeakTracks sptInfo;
if (indexCalculationDuration.TotalSeconds < 10.0)
{
// calculate a new decibel spectrogram
sptInfo = SpectralPeakTracks.CalculateSpectralPeakTracks(recording, startSample, endSample, frameSize, octaveScale, peakThreshold);
}
else
{
// use existing decibel spectrogram
sptInfo = new SpectralPeakTracks(deciBelSpectrogram, peakThreshold);
}
spectralIndices.SPT = sptInfo.SptSpectrum;
spectralIndices.RHZ = sptInfo.RhzSpectrum;
spectralIndices.RVT = sptInfo.RvtSpectrum;
spectralIndices.RPS = sptInfo.RpsSpectrum;
spectralIndices.RNG = sptInfo.RngSpectrum;
summaryIndices.SptDensity = sptInfo.TrackDensity;
// these are two other indices that I tried but they do not seem to add anything of interest.
//summaryIndices.AvgSptDuration = sptInfo.AvTrackDuration;
//summaryIndices.SptPerSecond = sptInfo.TotalTrackCount / subsegmentSecondsDuration;
// ######################################################################################################################################################
// vi: CLUSTERING - FIRST DETERMINE IF IT IS WORTH DOING
// return if (activeFrameCount too small || eventCount == 0 || short index calc duration) because no point doing clustering
if (activity.ActiveFrameCount <= 2 || Math.Abs(activity.EventCount) < 0.01 || indexCalculationDuration.TotalSeconds < 15)
{
// IN ADDITION return if indexCalculationDuration < 15 seconds because no point doing clustering on short time segment
// NOTE: Activity was calculated with 3dB threshold AFTER backgroundnoise removal.
//summaryIndices.AvgClusterDuration = TimeSpan.Zero;
summaryIndices.ClusterCount = 0;
summaryIndices.ThreeGramCount = 0;
return(result);
}
// YES WE WILL DO CLUSTERING! to determine cluster count (spectral diversity) and spectral persistence.
// Only use midband decibel SPECTRUM. In June 2016, the mid-band (i.e. the bird-band) was set to lowerBound=1000Hz, upperBound=8000hz.
// Actually do clustering of binary spectra. Must first threshold
double binaryThreshold = SpectralClustering.DefaultBinaryThresholdInDecibels;
var midBandSpectrogram = MatrixTools.Submatrix(deciBelSpectrogram, 0, lowerBinBound, deciBelSpectrogram.GetLength(0) - 1, middleBinBound);
var clusterInfo = SpectralClustering.ClusterTheSpectra(midBandSpectrogram, lowerBinBound, middleBinBound, binaryThreshold);
// Store two summary index values from cluster info
summaryIndices.ClusterCount = clusterInfo.ClusterCount;
summaryIndices.ThreeGramCount = clusterInfo.TriGramUniqueCount;
// As of May 2017, no longer store clustering results superimposed on spectrogram.
// If you want to see this, then call the TEST methods in class SpectralClustering.cs.
// #######################################################################################################################################################
// vii: set up other info to return
var freqPeaks = SpectralPeakTracks.ConvertSpectralPeaksToNormalisedArray(deciBelSpectrogram);
var scores = new List <Plot>
{
new Plot("Decibels", DataTools.normalise(dBEnvelopeSansNoise), ActivityAndCover.DefaultActivityThresholdDb),
new Plot("Active Frames", DataTools.Bool2Binary(activity.ActiveFrames), 0.0),
new Plot("Max Frequency", freqPeaks, 0.0), // relative location of freq maxima in spectra
};
result.Hits = sptInfo.Peaks;
result.TrackScores = scores;
return(result);
} // end Calculation of Summary and Spectral Indices