From e930492ccc5322a9ee00844ce9577d7d9f82651e Mon Sep 17 00:00:00 2001
From: Josh Hawkins <32435876+hawkeye217@users.noreply.github.com>
Date: Sun, 8 Mar 2026 17:22:38 -0500
Subject: [PATCH] Publish license plate box coordinates (#22337)

* publish the detected plate's box coordinates in tracked_object_update

* docs
---
 docs/docs/integrations/mqtt.md                |  3 ++-
 .../common/license_plate/mixin.py             | 19 +++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/docs/docs/integrations/mqtt.md b/docs/docs/integrations/mqtt.md
index ca3589df1..0ef6774a8 100644
--- a/docs/docs/integrations/mqtt.md
+++ b/docs/docs/integrations/mqtt.md
@@ -159,7 +159,8 @@ Published when a license plate is recognized on a car object. See the [License P
   "plate": "123ABC",
   "score": 0.95,
   "camera": "driveway_cam",
-  "timestamp": 1607123958.748393
+  "timestamp": 1607123958.748393,
+  "plate_box": [917, 487, 1029, 529] // box coordinates of the detected license plate in the frame
 }
 ```
 
diff --git a/frigate/data_processing/common/license_plate/mixin.py b/frigate/data_processing/common/license_plate/mixin.py
index c184b8b75..e4fbd1172 100644
--- a/frigate/data_processing/common/license_plate/mixin.py
+++ b/frigate/data_processing/common/license_plate/mixin.py
@@ -1225,6 +1225,8 @@ class LicensePlateProcessingMixin:
                 logger.debug(f"{camera}: License plate area below minimum threshold.")
                 return
 
+            plate_box = license_plate
+
             license_plate_frame = rgb[
                 license_plate[1] : license_plate[3],
                 license_plate[0] : license_plate[2],
@@ -1341,6 +1343,20 @@ class LicensePlateProcessingMixin:
                     logger.debug(f"{camera}: License plate is less than min_area")
                     return
 
+                # Scale back to original car coordinates and then to frame
+                plate_box_in_car = (
+                    license_plate[0] // 2,
+                    license_plate[1] // 2,
+                    license_plate[2] // 2,
+                    license_plate[3] // 2,
+                )
+                plate_box = (
+                    left + plate_box_in_car[0],
+                    top + plate_box_in_car[1],
+                    left + plate_box_in_car[2],
+                    top + plate_box_in_car[3],
+                )
+
                 license_plate_frame = car[
                     license_plate[1] : license_plate[3],
                     license_plate[0] : license_plate[2],
@@ -1404,6 +1420,8 @@ class LicensePlateProcessingMixin:
                     0, [license_plate_frame.shape[1], license_plate_frame.shape[0]] * 2
                 )
 
+                plate_box = tuple(int(x) for x in expanded_box)
+
                 # Crop using the expanded box
                 license_plate_frame = license_plate_frame[
                     int(expanded_box[1]) : int(expanded_box[3]),
@@ -1611,6 +1629,7 @@ class LicensePlateProcessingMixin:
                     "id": id,
                     "camera": camera,
                     "timestamp": start,
+                    "plate_box": plate_box,
                 }
             ),
         )