New tests and revise tests for Octave scale

Issue #332

src/AudioAnalysisTools/StandardSpectrograms/BaseSonogram.cs

@@ -239,6 +239,17 @@ public Image<Rgb24> GetImageFullyAnnotated(string title, Color? tag = null)
             return image;
         }
 
+        /// <summary>
+        /// This method fully annotates a short-time scale spectrogram.
+        /// The grid-lines are drawn according to indices in gridLineLocations.
+        /// Therefore the method will accept spectrograms with octave or any frequency scale.
+        /// The time scale is calculated from recording duration and width of image.
+        /// </summary>
+        /// <param name="image">The raw spectrogram image.</param>
+        /// <param name="title">To go on the title bar.</param>
+        /// <param name="gridLineLocations">A matrix of values.</param>
+        /// <param name="tag">Used to identify images??.</param>
+        /// <returns>The annotated spectrogram.</returns>
         public Image<Rgb24> GetImageFullyAnnotated(Image<Rgb24> image, string title, int[,] gridLineLocations, Color? tag = null)
         {
             if (image == null)
@@ -248,6 +259,7 @@ public Image<Rgb24> GetImageFullyAnnotated(Image<Rgb24> image, string title, int
 
             FrequencyScale.DrawFrequencyLinesOnImage(image, gridLineLocations, includeLabels: true);
 
+            // collect all the images and combine.
             var titleBar = DrawTitleBarOfGrayScaleSpectrogram(title, image.Width, tag);
             var timeBmp = ImageTrack.DrawTimeTrack(this.Duration, image.Width);
             var list = new List<Image<Rgb24>> { titleBar, timeBmp, image, timeBmp };

tests/Acoustics.Test/AudioAnalysisTools/DSP/FrequencyScaleTests.cs

@@ -270,9 +270,7 @@ public void TestMakeMelScaleSpectrogram()
         }
 
         /// <summary>
-        /// Test of the default standard split LINEAR-Octave FREQ SCALE
-        /// Check it on pure tone spectrum.
-        /// By default, the split between linear and octave is at 1000 Hz.
+        /// Test static method which returns bin index for a given frequency.
         /// </summary>
         [TestMethod]
         public void TestAssignmentOfGridLinesForOctaveFrequencyScale()
@@ -323,6 +321,40 @@ public void TestAssignmentOfGridLinesForOctaveFrequencyScale()
             Assert.That.MatricesAreEqual(expected, gridLineLocations);
         }
 
+        /// <summary>
+        /// Test static method which returns bin index for a given frequency.
+        /// </summary>
+        [TestMethod]
+        public void TestReturnOfBinIndex()
+        {
+            var freqScale = new FrequencyScale(FreqScaleType.OctaveDataReduction);
+
+            // test contents of the octave bin bounds matrix.
+            int[,] octaveBinBounds = freqScale.BinBounds;
+
+            Assert.AreEqual(20, octaveBinBounds.GetLength(0));
+
+            int hertzValue = 500;
+            var binId = freqScale.GetBinIdForHerzValue(hertzValue);
+            Assert.AreEqual(2, binId);
+
+            hertzValue = 1000;
+            binId = freqScale.GetBinIdForHerzValue(hertzValue);
+            Assert.AreEqual(4, binId);
+
+            hertzValue = 2000;
+            binId = freqScale.GetBinIdForHerzValue(hertzValue);
+            Assert.AreEqual(7, binId);
+
+            hertzValue = 4000;
+            binId = freqScale.GetBinIdForHerzValue(hertzValue);
+            Assert.AreEqual(12, binId);
+
+            hertzValue = 8000;
+            binId = freqScale.GetBinIdForHerzValue(hertzValue);
+            Assert.AreEqual(17, binId);
+        }
+
         /// <summary>
         /// Test of the default standard split LINEAR-Octave FREQ SCALE
         /// Check it on pure tone spectrum.
@@ -395,7 +427,7 @@ public void OctaveFrequencyScale1()
 
             var recording = new AudioRecording(recordingPath);
 
-            var fst = FreqScaleType.OctaveCustom;
+            var fst = FreqScaleType.OctaveDataReduction;
             int nyquist = recording.SampleRate / 2;
             int frameSize = 16384;
             int linearBound = 125;