private void StretchHistogram()
{
int[] redHistogram = HistogramCreator.GetHistogramFromByteArray(modifiedPixels, HistogramCreator.ColorMode.RED);
int[] greenHistogram = HistogramCreator.GetHistogramFromByteArray(modifiedPixels, HistogramCreator.ColorMode.GREEN);
int[] blueHistogram = HistogramCreator.GetHistogramFromByteArray(modifiedPixels, HistogramCreator.ColorMode.BLUE);
int minRed = HistogramCreator.GetIndexOfMinValue(redHistogram);
int minGreen = HistogramCreator.GetIndexOfMinValue(greenHistogram);
int minBlue = HistogramCreator.GetIndexOfMinValue(blueHistogram);
int maxRed = HistogramCreator.GetIndexOfMaxValue(redHistogram);
int maxGreen = HistogramCreator.GetIndexOfMaxValue(greenHistogram);
int maxBlue = HistogramCreator.GetIndexOfMaxValue(blueHistogram);
byte[] LUTred = new byte[256];
byte[] LUTgreen = new byte[256];
byte[] LUTblue = new byte[256];
for (int i = 0; i < 256; i++)
{
LUTred[i] = (byte)(255f / (maxRed - minRed) * (i - minRed));
LUTgreen[i] = (byte)(255f / (maxGreen - minGreen) * (i - minGreen));
LUTblue[i] = (byte)(255f / (maxBlue - minBlue) * (i - minBlue));
}
for (int i = 0; i < modifiedPixels.Length; i += 4)
{
modifiedPixels[i + 2] = LUTred[modifiedPixels[i + 2]];
modifiedPixels[i + 1] = LUTgreen[modifiedPixels[i + 1]];
modifiedPixels[i] = LUTblue[modifiedPixels[i]];
}
UpdateModifiedImageSource();
}
private void EqualizeHistogram()
{
int[] redHistogram = HistogramCreator.GetHistogramFromByteArray(modifiedPixels, HistogramCreator.ColorMode.RED);
int[] greenHistogram = HistogramCreator.GetHistogramFromByteArray(modifiedPixels, HistogramCreator.ColorMode.GREEN);
int[] blueHistogram = HistogramCreator.GetHistogramFromByteArray(modifiedPixels, HistogramCreator.ColorMode.BLUE);
int pixelsAmount = redHistogram.Sum();
double redSum = 0;
double greenSum = 0;
double blueSum = 0;
int minRed = HistogramCreator.GetIndexOfMinValue(redHistogram);
int minGreen = HistogramCreator.GetIndexOfMinValue(greenHistogram);
int minBlue = HistogramCreator.GetIndexOfMinValue(blueHistogram);
int redK = redHistogram.Count(x => x != 0);
int greenK = greenHistogram.Count(x => x != 0);
int blueK = blueHistogram.Count(x => x != 0);
double[] distributionRedHistogram = new double[256];
double[] distributionGreenHistogram = new double[256];
double[] distributionBlueHistogram = new double[256];
for (int i = 0; i < 256; i++)
{
redSum += (double)redHistogram[i] / (double)pixelsAmount;
distributionRedHistogram[i] = redSum;
greenSum += (double)greenHistogram[i] / (double)pixelsAmount;
distributionGreenHistogram[i] = greenSum;
blueSum += (double)blueHistogram[i] / (double)pixelsAmount;
distributionBlueHistogram[i] = blueSum;
}
int[] LUTred = new int[256];
int[] LUTgreen = new int[256];
int[] LUTblue = new int[256];
for (int i = 0; i < 256; i++)
{
LUTred[i] = (int)Math.Round((distributionRedHistogram[i] - distributionRedHistogram[minRed]) / (1 - distributionRedHistogram[minRed]) * (redK - 1));
LUTgreen[i] = (int)Math.Round((distributionGreenHistogram[i] - distributionGreenHistogram[minGreen]) / (1 - distributionGreenHistogram[minGreen]) * (greenK - 1));
LUTblue[i] = (int)Math.Round((distributionBlueHistogram[i] - distributionBlueHistogram[minBlue]) / (1 - distributionBlueHistogram[minBlue]) * (blueK - 1));
}
for (int i = 0; i < modifiedPixels.Length; i += 4)
{
modifiedPixels[i + 2] = (byte)LUTred[modifiedPixels[i + 2]];
modifiedPixels[i + 1] = (byte)LUTgreen[modifiedPixels[i + 1]];
modifiedPixels[i] = (byte)LUTblue[modifiedPixels[i]];
}
UpdateModifiedImageSource();
}
public Histogram(byte[] imagePixels, bool grayScale)
{
redHistogram = HistogramCreator.GetHistogramFromByteArray(imagePixels, HistogramCreator.ColorMode.RED);
greenHistogram = HistogramCreator.GetHistogramFromByteArray(imagePixels, HistogramCreator.ColorMode.GREEN);
blueHistogram = HistogramCreator.GetHistogramFromByteArray(imagePixels, HistogramCreator.ColorMode.BLUE);
averagedHistogram = HistogramCreator.GetHistogramFromByteArray(imagePixels, HistogramCreator.ColorMode.GRAYSCALE);
InitializeComponent();
if (grayScale)
{
RedValuesRadioBtn.IsEnabled = false;
GreenValuesRadioBtn.IsEnabled = false;
BlueValuesRadioBtn.IsEnabled = false;
}
}
private void OtsuThresholdCalculate()
{
int[] histogram = HistogramCreator.GetHistogramFromByteArray(pixels, HistogramCreator.ColorMode.GRAYSCALE);
int threshold = 0;
double minClassVariance = double.MaxValue;
for (int T = 0; T < 256; T++)
{
double classVariance = CalculateClassVariance(ref histogram, T);
if (classVariance < minClassVariance)
{
threshold = T;
minClassVariance = classVariance;
}
}
MessageBox.Show($"Znaleziony optymalny próg metodą Otsu wynosi {threshold}.");
ThresholdSpinValue.Value = (byte)threshold;
}