C#彩色图片灰度化算法网上几种算法中速度相对较快的
public static Bitmap MakeGrayscale(Bitmap original){ //create a blank bitmap the same size as original Bitmap newBitmap = new Bitmap(original.Width, original.Height); //get a graphics object from the new image Graphics g = Graphics.FromImage(newBitmap); //create the grayscale ColorMatrix System.Drawing.Imaging.ColorMatrix colorMatrix = new System.Drawing.Imaging.ColorMatrix( new float[][] { new float[] {.3f, .3f, .3f, 0, 0}, new float[] {.59f, .59f, .59f, 0, 0}, new float[] {.11f, .11f, .11f, 0, 0}, new float[] {0, 0, 0, 1, 0}, new float[] {0, 0, 0, 0, 1} }); //create some image attributes System.Drawing.Imaging.ImageAttributes attributes = new System.Drawing.Imaging.ImageAttributes(); //set the color matrix attribute attributes.SetColorMatrix(colorMatrix); //draw the original image on the new image //using the grayscale color matrix g.DrawImage(original, new Rectangle(0, 0, original.Width, original.Height), 0, 0, original.Width, original.Height, GraphicsUnit.Pixel, attributes); //dispose the Graphics object g.Dispose(); return newBitmap;}