C#环境下最大类间方差法的实现

 public static Image<Gray,byte> Otsu2D(Image<Gray, byte> img_in)
        {
            float[] histogram = new float[256];
            int w = img_in.Width;
            int h = img_in.Height;
            Bitmap bm = img_in.Bitmap;
            Bitmap bm_fix = bm.Clone(new Rectangle(0, 0, w, h), System.Drawing.Imaging.PixelFormat.Format24bppRgb);//解决“具有索引像素格式的图像不支持 SetPixel”的错误
            Bitmap bm_th = bm;
            int temp;
            double td = 0;
          

            for (int i = 0; i < w; i++)
            {
                for (int j = 0; j < h; j++)
                {
                    Color c = bm.GetPixel(i, j);
                    temp = ((int)c.R + (int)c.G + (int)c.B) / 3;
                    histogram[temp]++;
                }
            }

            //计算各像素频率和平均灰度
            float avgValue = 0;
            int numPixel = w * h;
            for (int i = 0; i < 256; i++)
            {
                histogram[i] = histogram[i] / numPixel;
                avgValue += i * histogram[i];
            }