def convertAbsCoco2relCoco(x, y, w, h, img_w, img_h):
    """
    INPUT: coco absolute parameters, image width, image height (in pixels)
    OUTPUT: coco relative parameters
    """
    x_rel = x/img_w
    y_rel = y/img_h
    w_rel = w/img_w
    h_rel = h/img_h
    return (x_rel, y_rel, w_rel, h_rel)