锐化图像滤镜

我有一个代码，可以保存在我的计算机上的图像，并将其处理成灰度，平滑的灰度和巧妙的边缘图像。我想做的是通过给图像添加某种类型的滤镜来锐化图像，然后转换为灰色和精明的边缘帧。我相信我的代码是正确的，但当我运行程序时，它似乎没有什么不同。锐化图像是否在错误的地方?它是不是被忽视了?有什么建议请告诉我。

      private void ProcessFrame()
  {
      String fileName = @"C:'filename";
               **Sharpen Image Filter code**
  public static Bitmap sharp(Bitmap img)
  {
      Bitmap sharpenImage = new Bitmap(img.Width, img.Height);
      int filterWidth = 3;
      int filterHeight = 3;
      int w = img.Width;
      int h = img.Height;
      double[,] filter = new double[filterWidth, filterHeight];
      filter[0, 0] = filter[0, 1] = filter[0, 2] = filter[1, 0] = filter[1, 2] = 
     filter[2,0]   =  filter[2, 1] = filter[2, 2] = -1;
      filter[1, 1] = 9;
      double factor = 1.0;
      double bias = 0.0;
      Color[,] result = new Color[img.Width, img.Height];
      for (int x = 0; x < w; ++x)
      {
          for (int y = 0; y < h; ++y)
          {
              double red = 0.0, green = 0.0, blue = 0.0;

              for (int filterX = 0; filterX < filterWidth; filterX++)
              {
                  for (int filterY = 0; filterY < filterHeight; filterY++)
                  {
                      int imageX = (x - filterWidth / 2 + filterX + w) % w;
                      int imageY = (y - filterHeight / 2 + filterY + h) % h;
                      Color imageColor = img.GetPixel(imageX, imageY);
                      red += imageColor.R * filter[filterX, filterY];
                      green += imageColor.G * filter[filterX, filterY];
                      blue += imageColor.B * filter[filterX, filterY];
                  }
                  int r = Math.Min(Math.Max((int)(factor * red + bias), 0), 255);
                  int g = Math.Min(Math.Max((int)(factor * green + bias), 0), 255);
                  int b = Math.Min(Math.Max((int)(factor * blue + bias), 0), 255);
                  result[x, y] = Color.FromArgb(r, g, b);
              }
          }
      }
      for (int i = 0; i < w; ++i)
      {
          for (int j = 0; j < h; ++j)
          {
              sharpenImage.SetPixel(i, j, result[i, j]);
          }
      }
      return sharpenImage;
  } 
**Sharpen Image Code Ends**