def pre_process_image(self, image):
        kernel = np.array([[0, 1, 0], [0, 1, 0], [0, 1, 0]])
        image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
        image = cv2.filter2D(image, -1, kernel)
        image = invert(image)
        image = binary_dilation(image, disk(2))