/// <summary>
/// </summary>
/// <param name="m">The spectral sonogram passes as matrix of doubles.</param>
public static void DoLocalOtsuThresholding(double[,] m, out byte[,] opByteMatrix)
{
int byteThreshold = 30;
int minPercentileBound = 5;
int maxPercentileBound = 95;
int temporalNh = 15;
int freqBinNh = 15;
int rowCount = m.GetLength(0);
int colCount = m.GetLength(1);
//double[,] normM = MatrixTools.NormaliseInZeroOne(m);
var ipByteMatrix = MatrixTools.ConvertMatrixOfDouble2Byte(m);
var bd1 = DataTools.GetByteDistribution(ipByteMatrix);
opByteMatrix = new byte[rowCount, colCount];
// for all cols i.e. freq bins
for (int col = freqBinNh; col < colCount - freqBinNh; col++)
{
// for all rows i.e. frames
for (int row = temporalNh; row < rowCount - temporalNh; row++)
{
var localMatrix = MatrixTools.Submatrix(ipByteMatrix, row - temporalNh, col - freqBinNh, row + temporalNh, col + freqBinNh);
// debug check for min and max - make sure it worked
int[] bd = DataTools.GetByteDistribution(localMatrix);
int[] histo = Histogram.Histo(localMatrix, out var minIntensity, out var maxIntensity);
int lowerBinBound = Histogram.GetPercentileBin(histo, minPercentileBound);
int upperBinBound = Histogram.GetPercentileBin(histo, maxPercentileBound);
int range = upperBinBound - lowerBinBound;
//normM[row, col] = (upperBinBound - lowerBinBound);
if (range > byteThreshold)
{
var thresholder = new OtsuThresholder();
byte[] vector = DataTools.Matrix2Array(localMatrix);
int threshold = thresholder.CalculateThreshold(vector);
if (localMatrix[temporalNh, freqBinNh] > threshold)
{
opByteMatrix[row, col] = 255;
}
}
}
}
// debug check for min and max - make sure it worked
var bd2 = DataTools.GetByteDistribution(opByteMatrix);
bd2 = null;
}
public static void GetOtsuThreshold(byte[,] matrix, out byte[,] m2, out int threshold)
{
int width = matrix.GetLength(1);
int height = matrix.GetLength(0);
byte[] vector = DataTools.Matrix2Array(matrix);
// Create Otsu Thresholder
OtsuThresholder thresholder = new OtsuThresholder();
threshold = thresholder.CalculateThreshold(vector, out var outputArray);
m2 = DataTools.Array2Matrix(outputArray, width, height);
}
public static void GetOtsuThreshold(byte[,] matrix, out byte[,] m2, out int threshold, out Image <Rgb24> histogramImage)
{
int width = matrix.GetLength(1);
int height = matrix.GetLength(0);
byte[] vector = DataTools.Matrix2Array(matrix);
// Create Otsu Thresholder
OtsuThresholder thresholder = new OtsuThresholder();
threshold = thresholder.CalculateThreshold(vector, out var outputArray);
m2 = DataTools.Array2Matrix(outputArray, width, height);
histogramImage = CreateHistogramFrame(thresholder, height, 256);
}
private static Image CreateHistogramFrame(OtsuThresholder thresholder, int width, int height)
{
width = 256; // histogram is one byte width.
int[] histData = thresholder.GetHistData();
int max = thresholder.getMaxLevelValue();
int threshold = thresholder.getThreshold();
var image = new Bitmap(width, height);
for (int col = 0; col < width; col++)
{
//int ptr = (numPixels - width) + col;
int val = height * histData[col] / max;
if (col == threshold)
{
for (int i = 0; i < height; i++)
{
image.SetPixel(col, i, Color.Red);
}
}
else
{
for (int i = 1; i <= val; i++)
{
image.SetPixel(col, height - i, Color.Black);
}
//histPlotData[ptr] = (byte)((val < i) ? (byte)255 : 0);
}
for (int i = 0; i < height; i++)
{
image.SetPixel(0, i, Color.Gray);
}
}
return(image);
}
