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Automate calculation of Octave scale bounds and its gridlines.
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Issue #332 Also need to add a new test for calculating grid locations and fix other tests.
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@towsey
towsey committed Aug 12, 2020
1 parent f3eb3ed commit 0a643f1
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Showing 11 changed files with 302 additions and 259 deletions.
25 changes: 11 additions & 14 deletions src/AnalysisPrograms/SpectrogramGenerator/SpectrogramGenerator.Core.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -225,15 +225,17 @@ public static AudioToSonogramResult GenerateSpectrogramImages(
NoiseReductionParameter = bgNoiseThreshold,
};

// Here are some of the possible octave frequency scales.
//var freqScale = new FrequencyScale(FreqScaleType.LinearOctaveStandard);
//var freqScale = new FrequencyScale(FreqScaleType.OctaveDataReduction);
//var freqScale = new FrequencyScale(FreqScaleType.Linear62OctaveTones31Nyquist11025);
//var freqScale = new FrequencyScale(FreqScaleType.Linear125OctaveTones32Nyquist11025);
//var type = FreqScaleType.OctaveCustom;
var type = FreqScaleType.OctaveStandard;
int nyquist = sampleRate / 2;
int linearBound = 1000;
int octaveToneCount = 31; // This value is ignored for OctaveStandard type.
int hertzGridInterval = 1000;
var scale = new FrequencyScale(type, nyquist, frameSize, linearBound, octaveToneCount, hertzGridInterval);

images.Add(
OctaveScaleSpectrogram,
GetOctaveScaleSpectrogram(octaveConfig, FreqScaleType.Linear62OctaveTones31Nyquist11025, recordingSegment, sourceRecordingName));
GetOctaveScaleSpectrogram(octaveConfig, scale, recordingSegment, sourceRecordingName));
}

// IMAGE 9) AmplitudeSpectrogram_LocalContrastNormalization
Expand Down Expand Up @@ -391,7 +393,7 @@ public static Image<Rgb24> GetMelScaleSpectrogram(
var titleBar = BaseSonogram.DrawTitleBarOfGrayScaleSpectrogram(
"MEL-FREQUENCY SPECTROGRAM " + sourceRecordingName,
image.Width,
ImageTags[CepstralSpectrogram]);
ImageTags[MelScaleSpectrogram]);
var startTime = TimeSpan.Zero;
var xAxisTicInterval = TimeSpan.FromSeconds(1);
TimeSpan xAxisPixelDuration = TimeSpan.FromSeconds(sonoConfig.WindowStep / (double)sonoConfig.SampleRate);
Expand Down Expand Up @@ -424,15 +426,10 @@ public static Image<Rgb24> GetCepstralSpectrogram(

public static Image<Rgb24> GetOctaveScaleSpectrogram(
SonogramConfig sgConfig,
FreqScaleType fst,
FrequencyScale freqScale,
AudioRecording recording,
string sourceRecordingName)
{
var freqScale = new FrequencyScale(fst)
{
WindowStep = 512,
};

// ensure that the freq scale and the config are consistent.
sgConfig.WindowSize = freqScale.WindowSize;
freqScale.WindowStep = sgConfig.WindowStep;
Expand All @@ -447,7 +444,7 @@ public static Image<Rgb24> GetOctaveScaleSpectrogram(
var titleBar = BaseSonogram.DrawTitleBarOfGrayScaleSpectrogram(
"OCTAVE-SCALE SPECTROGRAM " + sourceRecordingName,
image.Width,
ImageTags[CepstralSpectrogram]);
ImageTags[OctaveScaleSpectrogram]);
var startTime = TimeSpan.Zero;
var xAxisTicInterval = TimeSpan.FromSeconds(1);
TimeSpan xAxisPixelDuration = TimeSpan.FromSeconds(sgConfig.WindowStep / (double)sgConfig.SampleRate);
Expand Down
9 changes: 8 additions & 1 deletion src/AudioAnalysisTools/DSP/DSP_Filters.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -78,7 +78,14 @@ public static void TestMethod_GenerateSignal2()
int sampleRate = 64000;
double duration = 30; // signal duration in seconds
int[] harmonics = { 500, 1000, 2000, 4000, 8000 };
var freqScale = new FrequencyScale(FreqScaleType.Linear125OctaveTones28Nyquist32000);

//var freqScale = new FrequencyScale(FreqScaleType.Linear125OctaveTones28Nyquist32000);
int nyquist = sampleRate / 2;
int frameSize = 16384;
int linearBound = 125;
int octaveToneCount = 28;
int gridInterval = 1000;
var freqScale = new FrequencyScale(FreqScaleType.OctaveCustom, nyquist, frameSize, linearBound, octaveToneCount, gridInterval);
string path = @"C:\SensorNetworks\Output\Sonograms\UnitTestSonograms\SineSignal2.png";
var recording = GenerateTestRecording(sampleRate, duration, harmonics, WaveType.Cosine);

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75 changes: 66 additions & 9 deletions src/AudioAnalysisTools/DSP/FrequencyScale.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -25,12 +25,9 @@ public enum FreqScaleType
{
Linear = 0,
Mel = 1,
LinearOctaveStandard = 2,
Linear62OctaveTones31Nyquist11025 = 3,
Linear125OctaveTones32Nyquist11025 = 4,
Linear125OctaveTones28Nyquist32000 = 5,
Octaves24Nyquist32000 = 6,
OctaveDataReduction = 7,
OctaveCustom = 2,
OctaveStandard = 3,
OctaveDataReduction = 3,
}

public class FrequencyScale
Expand Down Expand Up @@ -59,7 +56,6 @@ public FrequencyScale(int nyquist, int frameSize, int hertzGridInterval)
/// </summary>
public FrequencyScale(FreqScaleType type, int nyquist, int frameSize, int finalBinCount, int hertzGridInterval)
{
this.ScaleType = type;
this.Nyquist = nyquist;
this.WindowSize = frameSize;
this.FinalBinCount = finalBinCount;
Expand All @@ -70,6 +66,10 @@ public FrequencyScale(FreqScaleType type, int nyquist, int frameSize, int finalB
this.GridLineLocations = SpectrogramMelScale.GetMelGridLineLocations(this.HertzGridInterval, nyquist, this.FinalBinCount);
this.LinearBound = 1000;
}
else if (type == FreqScaleType.OctaveStandard || type == FreqScaleType.OctaveCustom)
{
throw new Exception("Wrong Constructor. Use the Octave scale constructor.");
}
else
{
// linear is the default
Expand All @@ -79,6 +79,51 @@ public FrequencyScale(FreqScaleType type, int nyquist, int frameSize, int finalB
}
}

/// <summary>
/// Initializes a new instance of the <see cref="FrequencyScale"/> class.
/// CONSTRUCTION OF OCTAVE Frequency Scales
/// IMPORTANT NOTE: If you are converting Herz scale from LINEAR to OCTAVE, this conversion MUST be done BEFORE noise reduction
/// WARNING!: Changing the constants for the octave scales will have undefined effects.
/// The options below have been debugged to give what is required.
/// However other values have not been debugged - so user should check the output to ensure it is what is required.
/// NOTE: octaveToneCount = the number of fractional Hz steps within one octave. A piano octave contains 12 steps per octave.
/// NOTE: Not all combinations of parameter values are effective. nor have they all been tested.
/// The following have been tested:
/// nyquist=11025, linearBound=125 t0 1000, octaveToneCount=31, 32.
/// nyquist=11025, linearBound=125, octaveToneCount=31.
/// nyquist=32000, linearBound=125, octaveToneCount=28.
/// </summary>
/// <param name="type">Scale type must be an OCTAVE type.</param>
/// <param name="nyquist">sr / 2.</param>
/// <param name="frameSize">Assumes that frame size is power of 2.</param>
/// <param name="linearBound">The bound (Hz value) that divides lower linear and upper octave parts of the frequency scale.</param>
/// <param name="octaveToneCount">Number of fractional Hz steps within one octave. This is ignored in case of custom scale.</param>
/// <param name="hertzGridInterval">Only used where appropriate to draw frequency gridlines.</param>
public FrequencyScale(FreqScaleType type, int nyquist, int frameSize, int linearBound, int octaveToneCount, int hertzGridInterval)
{
this.ScaleType = type;
this.Nyquist = nyquist;
this.WindowSize = frameSize;
this.LinearBound = linearBound;

if (type == FreqScaleType.OctaveStandard)
{
// this scale automatically sets the octave tone count.
OctaveFreqScale.GetStandardOctaveScale(this);
}
else if (type == FreqScaleType.OctaveCustom)
{
this.ToneCount = octaveToneCount;
this.BinBounds = OctaveFreqScale.LinearToSplitLinearOctaveScale(nyquist, frameSize, linearBound, nyquist, octaveToneCount);
this.FinalBinCount = this.BinBounds.GetLength(0);
this.GridLineLocations = OctaveFreqScale.GetGridLineLocations(nyquist, linearBound, this.BinBounds);
}
else
{
throw new Exception("Unknown Octave scale.");
}
}

/// <summary>
/// Initializes a new instance of the <see cref="FrequencyScale"/> class.
/// CONSTRUCTOR.
Expand All @@ -104,10 +149,22 @@ public FrequencyScale(FreqScaleType fst)
// MEL SCALE spectrograms are available by direct call to SpectrogramGenerator.Core.GetMelScaleSpectrogram()
SpectrogramMelScale.GetStandardMelScale(this);
}
else if (fst == FreqScaleType.OctaveDataReduction)
{
// This spectral conversion is for data reduction purposes.
// It is a split linear-octave frequency scale.
OctaveFreqScale.GetDataReductionScale(this);

//The data reduction Octave Scale does not require grid lines.
this.GridLineLocations = new int[6, 2];
}
else if (fst == FreqScaleType.OctaveStandard || fst == FreqScaleType.OctaveCustom)
{
throw new Exception("Not enough info. Use an Octave scale constructor.");
}
else
{
// assume octave scale is only other option
OctaveFreqScale.GetOctaveScale(this);
throw new Exception("Unknown frequency scale type.");
}
}

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