Android : Blur Image detection with OpenCV results into heavy APK size

edit

I am working on one android app where I need to detect whether the image is blur. I implemented OpenCV with following Code:

private void opencvProcess() {

    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inDither = true;
    options.inPreferredConfig = Bitmap.Config.ARGB_8888;
    Bitmap image = decodeSampledBitmapFromFile(imageurl, 2000, 2000);
    int l = CvType.CV_8UC1; //8-bit grey scale image
    Mat matImage = new Mat();
    Utils.bitmapToMat(image, matImage);
    Mat matImageGrey = new Mat();
    Imgproc.cvtColor(matImage, matImageGrey, Imgproc.COLOR_BGR2GRAY);

    Bitmap destImage;
    destImage = Bitmap.createBitmap(image);
    Mat dst2 = new Mat();
    Utils.bitmapToMat(destImage, dst2);
    Mat laplacianImage = new Mat();
    dst2.convertTo(laplacianImage, l);
    Imgproc.Laplacian(matImageGrey, laplacianImage, CvType.CV_8U);
    Mat laplacianImage8bit = new Mat();
    laplacianImage.convertTo(laplacianImage8bit, l);

    Bitmap bmp = Bitmap.createBitmap(laplacianImage8bit.cols(), laplacianImage8bit.rows(), Bitmap.Config.ARGB_8888);
    Utils.matToBitmap(laplacianImage8bit, bmp);
    int[] pixels = new int[bmp.getHeight() * bmp.getWidth()];
    bmp.getPixels(pixels, 0, bmp.getWidth(), 0, 0, bmp.getWidth(), bmp.getHeight()); 
    int maxLap = -16777216; // 16m
    for (int pixel : pixels) {
        if (pixel > maxLap)
            maxLap = pixel;
    }

    int soglia = -6118750;
    if (maxLap <= soglia) {
        System.out.println("is blur image");
        Toast.makeText(Document_upload.this, "Blur Image", Toast.LENGTH_LONG).show();
    } else {
        Toast.makeText(Document_upload.this, "Clear Image", Toast.LENGTH_LONG).show();
    }

}

Though it works nicely, it resulted into heavy app size, almost 8 MB increased. I am using opencv3.0 sdk and all unused files as per my knowledge have been removed. Can anyone help me with some guidelines for reducing apk size.