def get_conversion(img_height, leftx_base, rightx_base):
    """
    Get the conversion factors for pixel/meters
    """
    # y-direction:
    # the lane lines are about 30 m long
    # in the perspective transform we take about half of that
    # and project it to the warped image
    ym_per_pix = 15/img_height

    # the lane is about 3.7 m wide
    # in the warped image that corresponds to the number of pixels between
    # the left and right lane
    xm_per_pix = 3.7/(rightx_base - leftx_base)

    return ym_per_pix, xm_per_pix