diff --git a/camera_calibration/src/camera_calibration/camera_checker.py b/camera_calibration/src/camera_calibration/camera_checker.py
index 6d5936882..19149b5ec 100755
--- a/camera_calibration/src/camera_calibration/camera_checker.py
+++ b/camera_calibration/src/camera_calibration/camera_checker.py
@@ -150,7 +150,7 @@ def image_corners(self, im):
         if ok:
             return corners, ids
         else:
-            return None
+            return None, None
 
     def handle_monocular(self, msg):