diff --git a/deepdoc/vision/postprocess.py b/deepdoc/vision/postprocess.py
index ec6f69d0..4aab3e0b 100644
--- a/deepdoc/vision/postprocess.py
+++ b/deepdoc/vision/postprocess.py
@@ -1,4 +1,5 @@
 import copy
+import re
 
 import numpy as np
 import cv2