Update README.md

README.md

@@ -3,6 +3,12 @@
 CORD dataset is cloned from [clovaai](https://github.com/clovaai/cord) GitHub repo
 
 - Box coordinates are normalized against image width/height
+- Labels with very few occurrences are replaced with O:
+
+```
+replacing_labels = ['menu.etc', 'menu.itemsubtotal', 'menu.sub_etc', 'menu.sub_unitprice', 'menu.vatyn',
+                    'void_menu.nm', 'void_menu.price', 'sub_total.othersvc_price']
+```
 
 ## Citation