mask = cv2.imread(str(args.input_mask), cv2.IMREAD_GRAYSCALE)
if mask is None:
    raise SystemExit(f"could not read mask: {args.input_mask}")

binary = np.where(mask > 0, 255, 0).astype(np.uint8)
kernel = cv2.getStructuringElement(
    cv2.MORPH_ELLIPSE,
    (args.kernel_size, args.kernel_size),
)