diff --git a/requirements.txt b/requirements.txt
index 6fea59c..2b1042e 100755
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,8 +1,8 @@
+chardet>=3.0.4
 click>=6.7
-matplotlib>=2.2.3
 numpy>=1.13.3
-opencv-python>=3.4.2.17
 openpyxl>=2.5.8
 pandas>=0.23.4
 pdfminer.six>=20170720
+PyPDF2>=1.26.0
 Sphinx>=1.7.9