public Bitmap WhiteBalance(Bitmap image)
{
float percentage = 99.3f;
var rHistogram = new Histogram <byte>();
var gHistogram = new Histogram <byte>();
var bHistogram = new Histogram <byte>();
var clonedImage = (Bitmap)image.Clone();
Rectangle rect = new Rectangle(0, 0, image.Width, image.Height);
System.Drawing.Imaging.BitmapData bitmapData =
clonedImage.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite, image.PixelFormat);
IntPtr ptr = bitmapData.Scan0;
int bytes = Math.Abs(bitmapData.Stride) * clonedImage.Height;
byte[] rgbValues = new byte[bytes];
System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes);
for (int i = 0; i < rgbValues.Length - 2; i += 3)
{
bHistogram.AddElement(rgbValues[i]);
gHistogram.AddElement(rgbValues[i + 1]);
rHistogram.AddElement(rgbValues[i + 2]);
}
(var rMin, var rMax) = HistogramStatistics.FindBoundariesOfXPercentage <byte>(rHistogram, percentage);
(var gMin, var gMax) = HistogramStatistics.FindBoundariesOfXPercentage <byte>(gHistogram, percentage);
(var bMin, var bMax) = HistogramStatistics.FindBoundariesOfXPercentage <byte>(bHistogram, percentage);
var rA = 255 / (rMax - rMin);
var rB = 0 - rA * rMin;
var gA = 255 / (gMax - gMin);
var gB = 0 - gA * gMin;
var bA = (255) / (bMax - bMin);
var bB = 0 - bA * bMin;
int val = 0;
for (int i = 0; i < rgbValues.Length - 2; i += 3)
{
val = rA * rgbValues[i + 2] + rB;
val = val > 255 ? 255 : val < 0 ? 0 : val;
rgbValues[i + 2] = (byte)val;
val = gA * rgbValues[i + 1] + gB;
val = val > 255 ? 255 : val < 0 ? 0 : val;
rgbValues[i + 1] = (byte)val;
val = bA * rgbValues[i] + bB;
val = val > 255 ? 255 : val < 0 ? 0 : val;
rgbValues[i] = (byte)val;
}
System.Runtime.InteropServices.Marshal.Copy(rgbValues, 0, ptr, bytes);
clonedImage.UnlockBits(bitmapData);
return(clonedImage);
}
