def x1y1wh_to_xcycwh(bbox):
    """Convert bounding boxes from
    [x_top, y_top, width, height] to
    [x_center, y_center, width, height]
    
    Note: coordinates measured from top,
    left corner of image and are normalized
    0-1 which we will keep"""
    x_top, y_top, w_box, h_box = bbox
    x_center = x_top + (0.5*w_box)
    y_center = y_top + (0.5*h_box)

    return x_center, y_center, w_box, h_box