Java-OpenCV Sobel

/**
     * Get the Sobel Mat of input image!
     * @param image The input image.
     * @return
    public Mat getSobelMat(Mat image) {
        if (image.empty()) {
            System.out.println("Please check the input image!");
            return image;
        }

        Mat gray = image.clone();
        if (3 == gray.channels()) {
            Imgproc.cvtColor(gray, gray, Imgproc.COLOR_BGR2GRAY);
        }

        Mat grad = new Mat();
        Mat grad_x = new Mat();
        Mat grad_y = new Mat();
        Mat abs_grad_x = new Mat();
        Mat abs_grad_y = new Mat();
        final int scharr_scale = 1;
        final int scharr_delta = 0;
        final int scharr_ddpeth = CvType.CV_16S;
        //Imgproc.Scharr(grayImg, grad_x, scharr_ddpeth, 1, 0, scharr_scale, scharr_delta, Core.BORDER_DEFAULT);
        //Imgproc.Scharr(grayImg, grad_y, scharr_ddpeth, 0, 1, scharr_scale, scharr_delta, Core.BORDER_DEFAULT);
        Imgproc.Sobel(gray, grad_x, scharr_ddpeth, 1, 0, 3, scharr_scale, scharr_delta, Core.BORDER_DEFAULT);
        Imgproc.Sobel(gray, grad_y, scharr_ddpeth, 0, 1, 3,scharr_scale, scharr_delta, Core.BORDER_DEFAULT);
        Core.convertScaleAbs(grad_x, abs_grad_x);
        Core.convertScaleAbs(grad_y, abs_grad_y);
        Core.addWeighted(abs_grad_x, 0.5, abs_grad_y, 0.5, 0, grad);
        return