diff --git a/requirements.txt b/requirements.txt
index 9b821c3..ef3fe31 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,5 +3,6 @@ ocrd >= 2.23.3
 numpy <1.24.0
 scikit-learn >= 0.23.2
 tensorflow < 2.13
+imutils >= 0.5.3
 numba <= 0.58.1
 loky