problem with combining RGB binary images

[meth]

hi. im doing an edge detection which will detect edges of each RGB channel and then combine them to show it as a final output. im now having a problem with combining the three as it doesnt show me a binary image, instead it has some colors on it. i have checked each binary image of the RGB and it works fine which gives the black and white image. to be clearer, following is the code:

private void processActionPerformed(java.awt.event.ActionEvent evt) {                                        
        width = inputimage.getWidth(null);
        height = inputimage.getHeight(null);

        inputbuff = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);

        Graphics r = inputbuff.getGraphics();
        r.drawImage(inputimage, 0, 0, null);
        r.dispose();

        process_red = new int[width * height];
        process_green = new int[width * height];
        process_blue = new int[width * height];
        process_grey = new int[width * height];
        process_rgb = new int[width * height];
        process_combine = new int[width * height];

        for (int i = 0; i < 256; i++) {
            freq_red[i] = freq_green[i] = freq_blue[i] = freq_grey[i] = 0;
        }

        for (int x = 0; x < width; x++) {
            for (int y = 0; y < height; y++) {
                int clr = inputbuff.getRGB(y, x);

                int red = (clr & 0x00ff0000) >> 16;
                int green = (clr & 0x0000ff00) >> 8;
                int blue = clr & 0x000000ff;
                int grey = (11 * red + 16 * green + 5 * blue) / 32;

                freq_red[red] += 1;
                freq_green[green] += 1;
                freq_blue[blue] += 1;
                freq_grey[grey] += 1;
            }
        }

        int threshold = 150;
        for (int i = 0; i < 256; i++) {
            freq_red[i] = applyThreshold(threshold, freq_red[i]);
            freq_green[i] = applyThreshold(threshold, freq_green[i]);
            freq_blue[i] = applyThreshold(threshold, freq_blue[i]);
            freq_grey[i] = applyThreshold(threshold, freq_grey[i]);
        }

        for (int x = 0; x < width; x++) {
            for (int y = 0; y < height; y++) {
                int clr = inputbuff.getRGB(y, x);

                int red = (clr & 0x00ff0000) >> 16;
                int green = (clr & 0x0000ff00) >> 8;
                int blue = clr & 0x000000ff;
                int grey = (11 * red + 16 * green + 5 * blue) / 32;

                red = freq_red[red];
                green = freq_green[green];
                blue = freq_blue[blue];
                grey = freq_grey[grey];


                int alpha = 0xff000000;
            int combine = alpha | (red <<16) |(green <<8)|blue;

                process_red[x * height + y] = (0xFF<<24)|(red<<16)|(red<<8)|red;
                process_green[x * height + y] = (0xFF<<24)|(green<<16)|(green<<8)|green;
                process_blue[x * height + y] = (0xFF<<24)|(blue<<16)|(blue<<8)|blue;
                process_grey[x * height + y] = (0xFF<<24)|(grey<<16)|(grey<<8)|grey;
                process_rgb[x * height + y] = clr;
                process_combine[x * height + y] = combine;

            }
        }

        image_red = new JFrame().createImage(new MemoryImageSource(width, height, process_red, 0, width));
        image_green = new JFrame().createImage(new MemoryImageSource(width, height, process_green, 0, width));
        image_blue = new JFrame().createImage(new MemoryImageSource(width, height, process_blue, 0, width));
        image_grey = new JFrame().createImage(new MemoryImageSource(width, height, process_grey, 0, width));
        image_rgb = new JFrame().createImage(new MemoryImageSource(width, height, process_rgb, 0, width));
        image_combine = new JFrame().createImage(new MemoryImageSource(width, height, process_combine, 0, width));

        buff_red = new BufferedImage(width,height, BufferedImage.TYPE_INT_RGB);
        buff_green = new BufferedImage(width,height, BufferedImage.TYPE_INT_RGB);
        buff_blue = new BufferedImage(width,height, BufferedImage.TYPE_INT_RGB);
        buff_grey = new BufferedImage(width,height, BufferedImage.TYPE_INT_RGB);
        buff_rgb = new BufferedImage(width,height, BufferedImage.TYPE_INT_RGB);
        buff_combine = new BufferedImage(width,height, BufferedImage.TYPE_INT_RGB);

        graph_red = buff_red.getGraphics();
        graph_green = buff_green.getGraphics();
        graph_blue = buff_blue.getGraphics();
        graph_grey = buff_grey.getGraphics();
        graph_rgb = buff_rgb.getGraphics();
        graph_combine = buff_combine.getGraphics();

        graph_red.drawImage(image_red, 0, 0, null);
        graph_green.drawImage(image_green, 0, 0, null);
        graph_blue.drawImage(image_blue, 0, 0, null);
        graph_grey.drawImage(image_grey, 0, 0, null);
        graph_rgb.drawImage(image_rgb, 0, 0, null);
        graph_combine.drawImage(image_combine, 0, 0, null);

        graph_red.dispose();
        graph_green.dispose();
        graph_blue.dispose();
        graph_grey.dispose();
        graph_rgb.dispose();
        graph_combine.dispose();


        repaint();
}

this is the sample image:


i suspected that the problem is with the alpha value:

int alpha = 0xff000000;
int combine = alpha | (red <<16) | (green <<8)|blue;

however, when i removed the alpha value it doesnt display anything. can anyone please help me? thanks in advance!