def calculate_axis_ratio(img):
    """
    Function returns axis-ratio of image.

    Parameters:
    ------------------------------
        img: (array), input image
    
    Returns:
    ------------------------------        
       float, Axis ratio (horizontal/vertical)
    """
    if len(img.shape) == 2:
        h, v = img.shape
    elif len(img.shape) == 3:
        h, v, _ = img.shape
    else:
        h, v = img.shape[0], img.shape[1]
        
    return h/v