diff --git a/script/device/Image.py b/script/device/Image.py
index 06500cd..da7dac3 100644
--- a/script/device/Image.py
+++ b/script/device/Image.py
@@ -124,7 +124,7 @@ class Image(DeviceBase, Readable):
             #self.current_reading = None
             return ret
         finally:
-            self.lock.release
+            self.image_lock.release()
     def read(self):
         return self.get_int()