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Thread: Median filter

  1. #1
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    Default Median filter

    I have to implement the median filter. I found an example on the internet but it does not run, I do not see the image, where am I wrong?

    public void median_RGB(Immagine img) {
     
            int maskSize = 3;
            int width = img.getW();
            int height = img.getH();
            int outputPixels[] = new int[width * height];
     
            int red[], green[], blue[];
            int xMin, xMax, yMin, yMax;
     
            int argb, reD, greenN, bluE;
     
            /** Median Filter operation */
            for (int y = 0; y < height; y++) {
                for (int x = 0; x < width; x++) {
                    int a = img.getAlpha(x, y);
                    red = new int[maskSize * maskSize];
                    green = new int[maskSize * maskSize];
                    blue = new int[maskSize * maskSize];
                    int count = 0;
                    xMin = x - (maskSize / 2);
                    xMax = x + (maskSize / 2);
                    yMin = y - (maskSize / 2);
                    yMax = y + (maskSize / 2);
                    for (int r = yMin; r <= yMax; r++) {
                        for (int c = xMin; c <= xMax; c++) {
                            if (r < 0 || r >= height || c < 0 || c >= width) {
                                /** Some portion of the mask is outside the image. */
                                continue;
                            } else {
                                argb = img.getOriginalImage().getRGB(c, r);
                                reD = (argb >> 16) & 0xff;
                                red[count] = reD;
                                greenN = (argb >> 8) & 0xff;
                                green[count] = greenN;
                                bluE = (argb) & 0xFF;
                                blue[count] = bluE;
                                count++;
                            }
                        }
                    }
     
                    /** sort red, green, blue array */
                    java.util.Arrays.sort(red);
                    java.util.Arrays.sort(green);
                    java.util.Arrays.sort(blue);
     
                    /** save median value in outputPixels array */
                    int index = (count % 2 == 0) ? count / 2 - 1 : count / 2;
                    logger.info("valore mediano " + index);
                    int p = (a << 24) | (red[index] << 16) | (green[index] << 8) | blue[index];
                    outputPixels[x + y * width] = p;
                }
            }
            /** Write the output pixels to the image pixels */
            for (int y = 0; y < height; y++) {
                for (int x = 0; x < width; x++) {
                    img.getOriginalImage().setRGB(x, y, outputPixels[x + y * width]);
                }
            }
        }
    Thanks


  2. #2
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    Default Re: Median filter

    What do you mean when you say "it does not run"? You have to be more precise, right now we cant help you.

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    Default Re: Median filter

    I do not see the image
    What image? Show us the code relevant to the problem with any error messages you're receiving.

  4. #4
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    Default Re: Median filter

    What do you mean when you say "it does not run"? You have to be more precise, right now we cant help you.
    The application successfully loads the images, apply various filters such as this LookUp table and everything works fine. If I apply the noise filter I can still see the image, then when I apply the median filter to the image no longer see it, is no longer displayed. The problem may be in the calculation of median filter but I can not figure out where, is more clear now? can you help?

    What image? Show us the code relevant to the problem with any error messages you're receiving.
    I have no real error messages, do not I see more correctly the image
    thanks

  5. #5
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    Default Re: Median filter

    Can you make a small, complete program that compiles, executes and shows the problem?
    If you don't understand my answer, don't ignore it, ask a question.

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