Gamma

This algorithm performs gamma correction of specified image in RGB color space.

   

• C#
• VB.Net

									public static void ApplyGamma(ref Bitmap bmp, double redComponent, double greenComponent, double blueComponent)
{
	if (redComponent < 0.2 || redComponent > 5) return;
	if (greenComponent < 0.2 || greenComponent > 5) return;
	if (blueComponent < 0.2 || blueComponent > 5) return;

	BitmapData bmpData = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);

	unsafe
	{
		byte* ptr = (byte*)bmpData.Scan0.ToPointer();
		int stopAddress = (int)ptr + bmpData.Stride * bmpData.Height;

		while ((int)ptr != stopAddress)
		{
			ptr[0] = (byte)Math.Min(255, (int)((255.0 * Math.Pow(ptr[0] / 255.0, 1.0 / blueComponent)) + 0.5));
			ptr[1] = (byte)Math.Min(255, (int)((255.0 * Math.Pow(ptr[1] / 255.0, 1.0 / greenComponent)) + 0.5));
			ptr[2] = (byte)Math.Min(255, (int)((255.0 * Math.Pow(ptr[2] / 255.0, 1.0 / redComponent)) + 0.5));

			ptr += 3;
		}
	}

	bmp.UnlockBits(bmpData);
}
								

Example

									Bitmap b = (Bitmap)Image.FromFile("rose.jpg");
ApplyGamma(ref b, 2, 1.6, 0.8);