diff --git a/robot/vision.py b/robot/vision.py
index 9ffa7c0..bf6381c 100755
--- a/robot/vision.py
+++ b/robot/vision.py
@@ -4,6 +4,7 @@
 import abc
 import logging
 import os
+from fcntl import lockf, LOCK_EX, LOCK_UN
 import threading
 import queue
 
@@ -417,7 +418,15 @@ def run(self):
                 if self._bounding_box:
                     frame = self._draw_bounding_box(frame, detections)
                 if self._save:
-                    cv2.imwrite(IMAGE_TO_SHEPHERD_PATH, frame)
+                    try:
+                        f = os.open(IMAGE_TO_SHEPHERD_PATH, os.O_RDWR)
+                        lockf(f, LOCK_EX)
+                        cv2.imwrite(IMAGE_TO_SHEPHERD_PATH, frame)
+                    finally:
+                        # This feels like a hack
+                        if "f" in locals():
+                            lockf(f, LOCK_UN)
+                            os.close(f)
                 if self._usb_stick:
                     self._write_to_usb(capture, detections)
                 if self._send_to_sheep: