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.Linear125Octaves7Tones28Nyquist32000); string path = @"C:\SensorNetworks\Output\Sonograms\UnitTestSonograms\SineSignal2.png"; var recording = GenerateTestRecording(sampleRate, duration, harmonics, WaveType.Cosine); // init the default sonogram config var sonoConfig = new SonogramConfig { WindowSize = freqScale.WindowSize, WindowOverlap = 0.2, SourceFName = "Signal2", NoiseReductionType = NoiseReductionType.None, NoiseReductionParameter = 0.0, }; var sonogram = new AmplitudeSonogram(sonoConfig, recording.WavReader); sonogram.Data = OctaveFreqScale.ConvertAmplitudeSpectrogramToDecibelOctaveScale(sonogram.Data, freqScale); // pick a row, any row var oneSpectrum = MatrixTools.GetRow(sonogram.Data, 40); oneSpectrum = DataTools.normalise(oneSpectrum); var peaks = DataTools.GetPeaks(oneSpectrum, 0.5); var peakIds = new List <int>(); for (int i = 5; i < peaks.Length - 5; i++) { if (peaks[i]) { int peakId = freqScale.BinBounds[i, 0]; peakIds.Add(peakId); LoggedConsole.WriteLine($"Spectral peak located in bin {peakId}, Herz={freqScale.BinBounds[i, 1]}"); } } //if (peaks[129] && peaks[257] && peaks[513] && peaks[1025] && peaks[2049]) if (peakIds[0] == 129 && peakIds[1] == 257 && peakIds[2] == 513 && peakIds[3] == 1025 && peakIds[4] == 2049) { LoggedConsole.WriteSuccessLine("Spectral Peaks found at correct places"); } else { LoggedConsole.WriteErrorLine("Spectral Peaks found at INCORRECT places"); } foreach (int h in harmonics) { LoggedConsole.WriteLine($"Harmonic {h}Hertz should be in bin {freqScale.GetBinIdForHerzValue(h)}"); } // spectrogram without framing, annotation etc var image = sonogram.GetImage(); string title = $"Spectrogram of Harmonics: {DataTools.Array2String(harmonics)} SR={sampleRate} Window={freqScale.WindowSize}"; image = sonogram.GetImageFullyAnnotated(image, title, freqScale.GridLineLocations); image.Save(path); }