diff --git a/dan/ocr/predict/inference.py b/dan/ocr/predict/inference.py
index e690b72d1b1d63b013b429fbff257f37f33c56e8..c869d4e1fb7e2d6a3583e360adef5e654079607a 100644
--- a/dan/ocr/predict/inference.py
+++ b/dan/ocr/predict/inference.py
@@ -125,6 +125,9 @@ class DAN:
         image = read_image(path)
         preprocessed_image = self.preprocessing_transforms(image)
 
+        if self.mean is None and self.std is None:
+            return preprocessed_image, preprocessed_image
+
         size = preprocessed_image.shape
         normalized_image = torch.zeros(size)