안드로이드에서 Bitmap을 빠르게 Blur처리하는법

Bitmap이미지를 Blur처리하고싶은데요 제가 짠 알고리즘은 픽셀단위로 루프를 돌아서 blur처리하는건데 640x480크기의 이미지파일을 blur처리할때 30초가 걸려요.

안드로이드 마켓에있는 상용앱들보면 blur처리할때 보통 5초정도로 엄청빠르던데 blur처리하는 다른 방법이 있을까요?

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    /**
     * Stack Blur v1.0 from
     * http://www.quasimondo.com/StackBlurForCanvas/StackBlurDemo.html
     * Java Author: Mario Klingemann <mario at quasimondo.com>
     * http://incubator.quasimondo.com
     *
     * created Feburary 29, 2004
     * Android port : Yahel Bouaziz <yahel at kayenko.com>
     * http://www.kayenko.com
     * ported april 5th, 2012
     *
     * This is a compromise between Gaussian Blur and Box blur
     * It creates much better looking blurs than Box Blur, but is
     * 7x faster than my Gaussian Blur implementation.
     *
     * I called it Stack Blur because this describes best how this
     * filter works internally: it creates a kind of moving stack
     * of colors whilst scanning through the image. Thereby it
     * just has to add one new block of color to the right side
     * of the stack and remove the leftmost color. The remaining
     * colors on the topmost layer of the stack are either added on
     * or reduced by one, depending on if they are on the right or
     * on the left side of the stack.
     *  
     * If you are using this algorithm in your code please add
     * the following line:
     * Stack Blur Algorithm by Mario Klingemann <mario@quasimondo.com>
     */
    
    public Bitmap fastblur(Bitmap sentBitmap, float scale, int radius) {
    
        int width = Math.round(sentBitmap.getWidth() * scale);
        int height = Math.round(sentBitmap.getHeight() * scale);
        sentBitmap = Bitmap.createScaledBitmap(sentBitmap, width, height, false);
    
        Bitmap bitmap = sentBitmap.copy(sentBitmap.getConfig(), true);
    
        if (radius < 1) {
            return (null);
        }
    
        int w = bitmap.getWidth();
        int h = bitmap.getHeight();
    
        int[] pix = new int[w * h];
        Log.e("pix", w + " " + h + " " + pix.length);
        bitmap.getPixels(pix, 0, w, 0, 0, w, h);
    
        int wm = w - 1;
        int hm = h - 1;
        int wh = w * h;
        int div = radius + radius + 1;
    
        int r[] = new int[wh];
        int g[] = new int[wh];
        int b[] = new int[wh];
        int rsum, gsum, bsum, x, y, i, p, yp, yi, yw;
        int vmin[] = new int[Math.max(w, h)];
    
        int divsum = (div + 1) >> 1;
        divsum *= divsum;
        int dv[] = new int[256 * divsum];
        for (i = 0; i < 256 * divsum; i++) {
            dv[i] = (i / divsum);
        }
    
        yw = yi = 0;
    
        int[][] stack = new int[div][3];
        int stackpointer;
        int stackstart;
        int[] sir;
        int rbs;
        int r1 = radius + 1;
        int routsum, goutsum, boutsum;
        int rinsum, ginsum, binsum;
    
        for (y = 0; y < h; y++) {
            rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
            for (i = -radius; i <= radius; i++) {
                p = pix[yi + Math.min(wm, Math.max(i, 0))];
                sir = stack[i + radius];
                sir[0] = (p & 0xff0000) >> 16;
                sir[1] = (p & 0x00ff00) >> 8;
                sir[2] = (p & 0x0000ff);
                rbs = r1 - Math.abs(i);
                rsum += sir[0] * rbs;
                gsum += sir[1] * rbs;
                bsum += sir[2] * rbs;
                if (i > 0) {
                    rinsum += sir[0];
                    ginsum += sir[1];
                    binsum += sir[2];
                } else {
                    routsum += sir[0];
                    goutsum += sir[1];
                    boutsum += sir[2];
                }
            }
            stackpointer = radius;
    
            for (x = 0; x < w; x++) {
    
                r[yi] = dv[rsum];
                g[yi] = dv[gsum];
                b[yi] = dv[bsum];
    
                rsum -= routsum;
                gsum -= goutsum;
                bsum -= boutsum;
    
                stackstart = stackpointer - radius + div;
                sir = stack[stackstart % div];
    
                routsum -= sir[0];
                goutsum -= sir[1];
                boutsum -= sir[2];
    
                if (y == 0) {
                    vmin[x] = Math.min(x + radius + 1, wm);
                }
                p = pix[yw + vmin[x]];
    
                sir[0] = (p & 0xff0000) >> 16;
                sir[1] = (p & 0x00ff00) >> 8;
                sir[2] = (p & 0x0000ff);
    
                rinsum += sir[0];
                ginsum += sir[1];
                binsum += sir[2];
    
                rsum += rinsum;
                gsum += ginsum;
                bsum += binsum;
    
                stackpointer = (stackpointer + 1) % div;
                sir = stack[(stackpointer) % div];
    
                routsum += sir[0];
                goutsum += sir[1];
                boutsum += sir[2];
    
                rinsum -= sir[0];
                ginsum -= sir[1];
                binsum -= sir[2];
    
                yi++;
            }
            yw += w;
        }
        for (x = 0; x < w; x++) {
            rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
            yp = -radius * w;
            for (i = -radius; i <= radius; i++) {
                yi = Math.max(0, yp) + x;
    
                sir = stack[i + radius];
    
                sir[0] = r[yi];
                sir[1] = g[yi];
                sir[2] = b[yi];
    
                rbs = r1 - Math.abs(i);
    
                rsum += r[yi] * rbs;
                gsum += g[yi] * rbs;
                bsum += b[yi] * rbs;
    
                if (i > 0) {
                    rinsum += sir[0];
                    ginsum += sir[1];
                    binsum += sir[2];
                } else {
                    routsum += sir[0];
                    goutsum += sir[1];
                    boutsum += sir[2];
                }
    
                if (i < hm) {
                    yp += w;
                }
            }
            yi = x;
            stackpointer = radius;
            for (y = 0; y < h; y++) {
                // Preserve alpha channel: ( 0xff000000 & pix[yi] )
                pix[yi] = ( 0xff000000 & pix[yi] ) | ( dv[rsum] << 16 ) | ( dv[gsum] << 8 ) | dv[bsum];
    
                rsum -= routsum;
                gsum -= goutsum;
                bsum -= boutsum;
    
                stackstart = stackpointer - radius + div;
                sir = stack[stackstart % div];
    
                routsum -= sir[0];
                goutsum -= sir[1];
                boutsum -= sir[2];
    
                if (x == 0) {
                    vmin[y] = Math.min(y + r1, hm) * w;
                }
                p = x + vmin[y];
    
                sir[0] = r[p];
                sir[1] = g[p];
                sir[2] = b[p];
    
                rinsum += sir[0];
                ginsum += sir[1];
                binsum += sir[2];
    
                rsum += rinsum;
                gsum += ginsum;
                bsum += binsum;
    
                stackpointer = (stackpointer + 1) % div;
                sir = stack[stackpointer];
    
                routsum += sir[0];
                goutsum += sir[1];
                boutsum += sir[2];
    
                rinsum -= sir[0];
                ginsum -= sir[1];
                binsum -= sir[2];
    
                yi += w;
            }
        }
    
        Log.e("pix", w + " " + h + " " + pix.length);
        bitmap.setPixels(pix, 0, w, 0, 0, w, h);
    
        return (bitmap);
    }
    

    구글링했더니 이런 소스를 찾았습니다. 메소드를 호출하면 간단하게 blur처리해줍니다.

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