diff --git a/dan/manager/dataset.py b/dan/manager/dataset.py
index d441c6a1bcd7ecb7bebafce72d740c4f3eb3477b..92de20dd646af824ff28ca11cfc4c1022c423295 100644
--- a/dan/manager/dataset.py
+++ b/dan/manager/dataset.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+import copy
 import json
 import os
 
@@ -112,7 +113,7 @@ class OCRDataset(Dataset):
 
     def get_sample_img(self, i):
         """
-        Get image by index
+        Compute the final image size and position after feature extraction
         """
         if self.load_in_memory:
             return self.samples[i]["img"]
diff --git a/dan/manager/ocr.py b/dan/manager/ocr.py
index c0e832b39c78f6a5612be8183cb1d582ae6e518b..d7f72ea34a317e1ac740e48b100b8ce371bdf538 100644
--- a/dan/manager/ocr.py
+++ b/dan/manager/ocr.py
@@ -1,5 +1,4 @@
 # -*- coding: utf-8 -*-
-import copy
 import os
 import pickle
 import random