图像灰度处理

///------------灰度图处理计算方法--------------//
///------浮点算法：Gray=R*0.3+G*0.59+B*0.11----//
///------整数方法：Gray=(R*30+G*59+B*11)/100---//
///------移位方法：Gray =(R*28+G*151+B*77)>>8--//
///------平均值法：Gray=（R+G+B）/3------------//
///------仅取绿色：Gray=G----------------------//

        /// <summary>
        /// 图像灰度处理
        /// </summary>
        /// <param name="style">处理方式</param>
        public  Bitmap GrayImage(string style)
        {
            Bitmap bmp = new Bitmap(this.pbOld.Image);
            Bitmap newBmp = new Bitmap(this.pbOld.Image);
            Color color = new Color();
            Color newColor;
            Byte r, g, b, gray=0;

            for (int i = 0; i < bmp.Width; i++)
            {
                for (int j = 0; j < bmp.Height; j++)
                {
                    //获取颜色
                    color = bmp.GetPixel(i, j);
                    r = color.R;
                    g = color.G;
                    b = color.B;
                    switch (style)
                    { 
                        case "move":
                            //采用移位运算
                            gray = (Byte)((r * 19596 + g * 38469 + b * 7472) >> 16);
                            break;
                        case "float":
                            gray = (Byte)(r * 0.3 + g * 0.59 + b * 0.11);
                            break;
                        case "int":
                            gray=(Byte)((r*30+g*59+b*11)/100);
                            break;
                        case "avg":
                            gray=(Byte)((r+g+b)/3);
                            break;
                        case "green":
                            gray = g;
                            break;
                    }
                    
                    newColor = Color.FromArgb(gray, gray, gray);
                    newBmp.SetPixel(i, j, newColor);
                }
            }
            return newBmp;
        }