private void EqualizeHistogram(EqualizeMethod method)
{
FastBitmap bmp = ((ImageForm)ActiveMdiChild).Image;
Histogram hist = ((ImageForm)ActiveMdiChild).Histogram;
ImageHelper.EqualizeHistogram(bmp, hist, method);
((ImageForm)ActiveMdiChild).Refresh();
}
public static void EqualizeHistogram(FastBitmap bmp, Histogram hist, EqualizeMethod method)
{
int R = 0;
double hInt = 0.0;
double[] left = new double[256];
double[] right = new double[256];
int[] newValue = new int[256];
for (int i = 0; i < 256; ++i)
{
left[i] = R;
hInt += hist.HistogramTable[i];
while (hInt > hist.Average)
{
hInt -= hist.Average;
if (R < 255)
{
R++;
}
}
right[i] = R;
switch (method)
{
case EqualizeMethod.Averages:
newValue[i] = (int)((left[i] + right[i]) / 2.0);
break;
case EqualizeMethod.Random:
newValue[i] = (int)(right[i] - left[i]);
break;
case EqualizeMethod.Own:
newValue[i] = (int)((left[i] + right[i]) / 2.0);
break;
}
}
for (int i = 0; i < bmp.Size.Width; ++i)
{
for (int j = 0; j < bmp.Size.Height; ++j)
{
Color color = bmp[i, j];
if (left[color.R] == right[color.R])
{
bmp[i, j] = Color.FromArgb(color.A, (int)left[color.R], (int)left[color.R], (int)left[color.R]);
}
else
{
switch (method)
{
case EqualizeMethod.Averages:
bmp[i, j] = Color.FromArgb(color.A, (int)newValue[color.R], (int)newValue[color.R], (int)newValue[color.R]);
break;
case EqualizeMethod.Random:
Random rnd = new Random();
int value = (int)left[color.R] + rnd.Next(newValue[color.R] + 1);
bmp[i, j] = Color.FromArgb(color.A, value, value, value);
break;
case EqualizeMethod.Neighborhood8:
double average = 0;
int count = 0;
foreach (Point offset in new Point[] { new Point(1, 0), new Point(-1, 0), new Point(0, 1), new Point(0, -1), new Point(1, 1), new Point(-1, -1), new Point(-1, 1), new Point(1, -1) })
{
if (i + offset.X >= 0 && i + offset.X < bmp.Width && j + offset.Y >= 0 && j + offset.Y < bmp.Height)
{
average += bmp[i + offset.X, j + offset.Y].R;
++count;
}
}
average /= count;
if (average > right[color.R])
{
bmp[i, j] = Color.FromArgb(color.A, (int)right[color.R], (int)right[color.R], (int)right[color.R]);
}
else if (average < left[color.R])
{
bmp[i, j] = Color.FromArgb(color.A, (int)left[color.R], (int)left[color.R], (int)left[color.R]);
}
else
{
bmp[i, j] = Color.FromArgb(color.A, (int)average, (int)average, (int)average);
}
break;
case EqualizeMethod.Own:
bmp[i, j] = Color.FromArgb(color.A, (int)newValue[color.R], (int)newValue[color.R], (int)newValue[color.R]);
break;
}
}
}
}
}