/// <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 GetGlobalOtsuThreshold(double[,] inputMatrix, out byte[,] opByteMatrix, out double opThreshold, out Image <Rgb24> histogramImage)
{
if (inputMatrix == null)
{
throw new ArgumentNullException(nameof(inputMatrix));
}
var normMatrix = MatrixTools.NormaliseInZeroOne(inputMatrix, out var min, out var max);
var byteMatrix = MatrixTools.ConvertMatrixOfDouble2Byte(normMatrix);
GetOtsuThreshold(byteMatrix, out opByteMatrix, out var threshold, out histogramImage);
opThreshold = threshold / (double)byte.MaxValue;
opThreshold = min + (opThreshold * (max - min));
}
