Sharpen Image Filter

Question

I have code that takes an image saved on my computer and processes into a grayscale, smoothed gray, and canny edge image. What I would like it to do is sharpen the image by adding some type of filter to the image and then convert to gray and canny edge frame. I believe I have the code correct but when I run the program it doesn't seem to do anything different. Is the sharpen image in the wrong place? Is it somehow getting overlooked? Any suggestions please let me know.

      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**

score 1 · Accepted Answer · answered Dec 23 '11 at 14:24

1

I guess I could be missing it, but it doesn't look like you are ever invoking your sharpening code on an image. That would certainly explain why the result isn't changing!

answered Dec 23 '11 at 14:24

Mikeb

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In the sharpen image code I changed 'img' to 'frame' because that was how the original image was coming in. Is that not correct? – LewSim Dec 23 '11 at 14:52
"Sharp" is a method that takes a Bitmap as a parameter and returns a Bitmap. For the code inside that method to run, it needs to be called. Much like you call the method "foo" from inside the method "processFrame", except I assume you will need to convert from the OpenCV Image type to a Bitmap type, or rewrite Sharp to use CV's classes. I would expect OpenCV to have a built in function to use. – Mikeb Dec 23 '11 at 16:11
For example : see here : http://stackoverflow.com/questions/4993082/how-to-sharpen-an-image-in-opencv – Mikeb Dec 23 '11 at 16:11

Sharpen Image Filter

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