0 Replies Latest reply: Feb 22, 2010 9:23 AM by 843802 RSS

    JAI dct data interpretation

    843802
      DCT transforms data form space domain to frequency domain.
      I 've appliet JAI dct operator to an image.
      Then, i tried to inspect the values of the dct output:

      This is my code:
      final String filename = "sample\\viola.jpg";          
                
                RenderedImage src = (RenderedImage)JAI.create("fileload", filename);
                int width  = src.getWidth();
                int height = src.getHeight();          
                
                ParameterBlock pb = (new ParameterBlock()).addSource(src);
                PlanarImage dct = JAI.create("dct", pb, null);     
                
                int w = dct.getWidth();
                int h = dct.getHeight();
                // obtain information in frequency domain
                int dctData[] = 
                     dct.getData().getPixels(0, 0, w, h, (int[])null);
                double[] pixels = new double[dctData.length];
                
                for (int i = 0; i < w; i++)
                     System.out.println(dctData[i] + ", ");
      Now, i want to say, if there's a way to interpret this result and,
      for understand what they means.

      For example, first dct data otput are the follow integers: 51518, 52896, 54628...

      Then, i want to say what happens if i set to 0 the dct data falling within a certain range, (thus removing some frequencies), and i re-apply dct...