>>123
  face = cascade.detectMultiScale(BG)
  if len(face) > 0:
    for r in face:
      x, y = r[0:2]
      width, height = r[0:2] + r[2:4]
      logo = cv2.resize(FG, (width-x, height-y))
      rows, cols = logo.shape[:2]
      roi = BG[y:rows + y, x:cols + x]
      gray = cv2.cvtColor(logo, cv2.COLOR_BGR2GRAY)
      ret, mask = cv2.threshold(gray, 10, 255, cv2.THRESH_BINARY)
      mask_inv = cv2.bitwise_not(mask)
      img_BG = cv2.bitwise_and(roi,roi,mask = mask_inv)
      img_FG = cv2.bitwise_and(logo,logo,mask = mask)
      BG[y:rows+y, x:cols+x] = cv2.add(img_BG, img_FG)