diff --git a/processing/post/addNorm.py b/processing/post/addNorm.py
index ff8b4956a..c8c0b05bf 100755
--- a/processing/post/addNorm.py
+++ b/processing/post/addNorm.py
@@ -4,6 +4,8 @@ import os
 import sys
 from optparse import OptionParser
 
+import numpy as np
+
 import damask