Ejemplo n.º 1
0
class TrackedObjectProcessor(threading.Thread):
    def __init__(self, config, client, topic_prefix, tracked_objects_queue,
                 event_queue):
        threading.Thread.__init__(self)
        self.config = config
        self.client = client
        self.topic_prefix = topic_prefix
        self.tracked_objects_queue = tracked_objects_queue
        self.event_queue = event_queue
        self.camera_data = defaultdict(
            lambda: {
                'best_objects': {},
                'object_status': defaultdict(lambda: defaultdict(lambda: 'OFF')
                                             ),
                'tracked_objects': {},
                'current_frame': np.zeros((720, 1280, 3), np.uint8),
                'current_frame_time': 0.0,
                'object_id': None
            })
        self.plasma_client = PlasmaManager()
        self.room_tracker = None
        self.room_tracker_mqtt_state = {}

    def get_best(self, camera, label):
        if label in self.camera_data[camera]['best_objects']:
            return self.camera_data[camera]['best_objects'][label]['frame']
        else:
            return None

    def get_current_frame(self, camera):
        return self.camera_data[camera]['current_frame']

    def run(self):
        while True:
            camera, frame_time, current_tracked_objects = self.tracked_objects_queue.get(
            )

            config = self.config[camera]
            best_objects = self.camera_data[camera]['best_objects']
            current_object_status = self.camera_data[camera]['object_status']
            tracked_objects = self.camera_data[camera]['tracked_objects']

            current_ids = current_tracked_objects.keys()
            previous_ids = tracked_objects.keys()
            removed_ids = list(set(previous_ids).difference(current_ids))
            new_ids = list(set(current_ids).difference(previous_ids))
            updated_ids = list(set(current_ids).intersection(previous_ids))

            for id in new_ids:
                tracked_objects[id] = current_tracked_objects[id]
                # publish events to mqtt
                self.client.publish(
                    f"{self.topic_prefix}/{camera}/events/start",
                    json.dumps(tracked_objects[id]),
                    retain=False)
                self.event_queue.put(('start', camera, tracked_objects[id]))

            for id in updated_ids:
                tracked_objects[id] = current_tracked_objects[id]

            for id in removed_ids:
                # publish events to mqtt
                tracked_objects[id]['end_time'] = frame_time
                self.client.publish(f"{self.topic_prefix}/{camera}/events/end",
                                    json.dumps(tracked_objects[id]),
                                    retain=False)
                self.event_queue.put(('end', camera, tracked_objects[id]))
                del tracked_objects[id]

            self.camera_data[camera]['current_frame_time'] = frame_time

            ###
            # Update room tracker if enabled
            ###
            room_tracker_conf = config.get("room_tracker", None)
            if room_tracker_conf is not None and room_tracker_conf.get(
                    "enabled", False):
                if self.room_tracker is None:
                    self.room_tracker = RoomTracker(room_tracker_conf)
                self.room_tracker.on_change(frame_time, tracked_objects)

            ###
            # Draw tracked objects on the frame
            ###
            current_frame = self.plasma_client.get(f"{camera}{frame_time}")

            if not current_frame is plasma.ObjectNotAvailable:
                # draw the bounding boxes on the frame
                for obj in tracked_objects.values():
                    thickness = 2
                    color = COLOR_MAP[obj['label']]

                    if obj['frame_time'] != frame_time:
                        thickness = 1
                        color = (255, 0, 0)

                    # draw the bounding boxes on the frame
                    box = obj['box']
                    draw_box_with_label(
                        current_frame,
                        box[0],
                        box[1],
                        box[2],
                        box[3],
                        obj['label'],
                        f"{int(obj['score']*100)}% {int(obj['area'])}",
                        thickness=thickness,
                        color=color)
                    # draw the regions on the frame
                    region = obj['region']
                    cv2.rectangle(current_frame, (region[0], region[1]),
                                  (region[2], region[3]), (0, 255, 0), 1)

                if config['snapshots']['show_timestamp']:
                    time_to_show = datetime.datetime.fromtimestamp(
                        frame_time).strftime("%m/%d/%Y %H:%M:%S")
                    cv2.putText(current_frame,
                                time_to_show, (10, 30),
                                cv2.FONT_HERSHEY_SIMPLEX,
                                fontScale=.8,
                                color=(255, 255, 255),
                                thickness=2)

                # Draw room tracker area points
                if self.room_tracker is not None:
                    for room_name, c in self.room_tracker.rooms_conf.items():
                        p = (c["point_x"], c["point_y"])
                        cv2.rectangle(current_frame, (p[0] - 10, p[1] - 10),
                                      (p[0] + 10, p[1] + 10), (255, 0, 0), 3)

                ###
                # Set the current frame
                ###
                self.camera_data[camera]['current_frame'] = current_frame

                # delete the previous frame from the plasma store and update the object id
                if not self.camera_data[camera]['object_id'] is None:
                    self.plasma_client.delete(
                        self.camera_data[camera]['object_id'])
                self.camera_data[camera]['object_id'] = f"{camera}{frame_time}"

            ###
            # Maintain the highest scoring recent object and frame for each label
            ###
            for obj in tracked_objects.values():
                # if the object wasn't seen on the current frame, skip it
                if obj['frame_time'] != frame_time:
                    continue
                if obj['label'] in best_objects:
                    now = datetime.datetime.now().timestamp()
                    # if the object is a higher score than the current best score
                    # or the current object is more than 1 minute old, use the new object
                    if obj['score'] > best_objects[obj['label']]['score'] or (
                            now -
                            best_objects[obj['label']]['frame_time']) > 60:
                        obj['frame'] = np.copy(
                            self.camera_data[camera]['current_frame'])
                        best_objects[obj['label']] = obj
                        # send updated snapshot over mqtt
                        best_frame = cv2.cvtColor(obj['frame'],
                                                  cv2.COLOR_RGB2BGR)
                        ret, jpg = cv2.imencode('.jpg', best_frame)
                        if ret:
                            jpg_bytes = jpg.tobytes()
                            self.client.publish(
                                f"{self.topic_prefix}/{camera}/{obj['label']}/snapshot",
                                jpg_bytes,
                                retain=True)
                else:
                    obj['frame'] = np.copy(
                        self.camera_data[camera]['current_frame'])
                    best_objects[obj['label']] = obj

            ###
            # Report over MQTT
            ###
            # count objects by type
            obj_counter = Counter()
            for obj in tracked_objects.values():
                obj_counter[obj['label']] += 1

            # report on detected objects
            for obj_name, count in obj_counter.items():
                new_status = 'ON' if count > 0 else 'OFF'
                if new_status != current_object_status[obj_name]:
                    current_object_status[obj_name] = new_status
                    self.client.publish(
                        f"{self.topic_prefix}/{camera}/{obj_name}",
                        new_status,
                        retain=False)
                    # send the best snapshot over mqtt
                    best_frame = cv2.cvtColor(best_objects[obj_name]['frame'],
                                              cv2.COLOR_RGB2BGR)
                    ret, jpg = cv2.imencode('.jpg', best_frame)
                    if ret:
                        jpg_bytes = jpg.tobytes()
                        self.client.publish(
                            f"{self.topic_prefix}/{camera}/{obj_name}/snapshot",
                            jpg_bytes,
                            retain=True)

            # expire any objects that are ON and no longer detected
            expired_objects = [
                obj_name for obj_name, status in current_object_status.items()
                if status == 'ON' and not obj_name in obj_counter
            ]
            for obj_name in expired_objects:
                current_object_status[obj_name] = 'OFF'
                self.client.publish(f"{self.topic_prefix}/{camera}/{obj_name}",
                                    'OFF',
                                    retain=False)
                # send updated snapshot over mqtt
                best_frame = cv2.cvtColor(best_objects[obj_name]['frame'],
                                          cv2.COLOR_RGB2BGR)
                ret, jpg = cv2.imencode('.jpg', best_frame)
                if ret:
                    jpg_bytes = jpg.tobytes()
                    self.client.publish(
                        f"{self.topic_prefix}/{camera}/{obj_name}/snapshot",
                        jpg_bytes,
                        retain=True)

            # report area tracking
            if self.room_tracker is not None:
                for room_name, _ in self.room_tracker.rooms_conf.items():
                    ppl_count = self.room_tracker.get_area_count(room_name)
                    status = "ON" if ppl_count > 0 else "OFF"
                    timestamp = self.room_tracker.get_latest_change_timestamp(
                        room_name)
                    r = {
                        "status": status,
                        "count": ppl_count,
                        "timestamp": timestamp,
                    }
                    if room_name in self.room_tracker_mqtt_state and self.room_tracker_mqtt_state[
                            room_name] == r:
                        continue
                    else:
                        self.client.publish(
                            f"{self.topic_prefix}/{camera}/area/{room_name}",
                            json.dumps(r),
                            retain=False)
                        self.room_tracker_mqtt_state[room_name] = r
Ejemplo n.º 2
0
class TrackedObjectProcessor(threading.Thread):
    def __init__(self, camera_config, zone_config, client, topic_prefix,
                 tracked_objects_queue, event_queue, stop_event):
        threading.Thread.__init__(self)
        self.camera_config = camera_config
        self.zone_config = zone_config
        self.client = client
        self.topic_prefix = topic_prefix
        self.tracked_objects_queue = tracked_objects_queue
        self.event_queue = event_queue
        self.stop_event = stop_event
        self.camera_data = defaultdict(
            lambda: {
                'best_objects': {},
                'object_status': defaultdict(lambda: defaultdict(lambda: 'OFF')
                                             ),
                'tracked_objects': {},
                'current_frame': np.zeros((720, 1280, 3), np.uint8),
                'current_frame_time': 0.0,
                'object_id': None
            })
        self.zone_data = defaultdict(
            lambda: {
                'object_status': defaultdict(lambda: defaultdict(lambda: 'OFF')
                                             ),
                'contours': {}
            })

        # create zone contours
        for name, config in zone_config.items():
            for camera, camera_zone_config in config.items():
                coordinates = camera_zone_config['coordinates']
                if isinstance(coordinates, list):
                    self.zone_data[name]['contours'][camera] = np.array(
                        [[int(p.split(',')[0]),
                          int(p.split(',')[1])] for p in coordinates])
                elif isinstance(coordinates, str):
                    points = coordinates.split(',')
                    self.zone_data[name]['contours'][camera] = np.array(
                        [[int(points[i]), int(points[i + 1])]
                         for i in range(0, len(points), 2)])
                else:
                    print(
                        f"Unable to parse zone coordinates for {name} - {camera}"
                    )

        # set colors for zones
        colors = plt.cm.get_cmap('tab10', len(self.zone_data.keys()))
        for i, zone in enumerate(self.zone_data.values()):
            zone['color'] = tuple(int(round(255 * c)) for c in colors(i)[:3])

        self.plasma_client = PlasmaManager(self.stop_event)

    def get_best(self, camera, label):
        if label in self.camera_data[camera]['best_objects']:
            return self.camera_data[camera]['best_objects'][label]['frame']
        else:
            return None

    def get_current_frame(self, camera):
        return self.camera_data[camera]['current_frame']

    def run(self):
        while True:
            if self.stop_event.is_set():
                print(f"Exiting object processor...")
                break

            try:
                camera, frame_time, current_tracked_objects = self.tracked_objects_queue.get(
                    True, 10)
            except queue.Empty:
                continue

            camera_config = self.camera_config[camera]
            best_objects = self.camera_data[camera]['best_objects']
            current_object_status = self.camera_data[camera]['object_status']
            tracked_objects = self.camera_data[camera]['tracked_objects']

            current_ids = current_tracked_objects.keys()
            previous_ids = tracked_objects.keys()
            removed_ids = list(set(previous_ids).difference(current_ids))
            new_ids = list(set(current_ids).difference(previous_ids))
            updated_ids = list(set(current_ids).intersection(previous_ids))

            for id in new_ids:
                # only register the object here if we are sure it isnt a false positive
                if not filter_false_positives(current_tracked_objects[id]):
                    tracked_objects[id] = current_tracked_objects[id]
                    # publish events to mqtt
                    self.client.publish(
                        f"{self.topic_prefix}/{camera}/events/start",
                        json.dumps(tracked_objects[id]),
                        retain=False)
                    self.event_queue.put(
                        ('start', camera, tracked_objects[id]))

            for id in updated_ids:
                tracked_objects[id] = current_tracked_objects[id]

            for id in removed_ids:
                # publish events to mqtt
                tracked_objects[id]['end_time'] = frame_time
                self.client.publish(f"{self.topic_prefix}/{camera}/events/end",
                                    json.dumps(tracked_objects[id]),
                                    retain=False)
                self.event_queue.put(('end', camera, tracked_objects[id]))
                del tracked_objects[id]

            self.camera_data[camera]['current_frame_time'] = frame_time

            # build a dict of objects in each zone for current camera
            current_objects_in_zones = defaultdict(lambda: [])
            for obj in tracked_objects.values():
                bottom_center = (obj['centroid'][0], obj['box'][3])
                # check each zone
                for name, zone in self.zone_data.items():
                    current_contour = zone['contours'].get(camera, None)
                    # if the current camera does not have a contour for this zone, skip
                    if current_contour is None:
                        continue
                    # check if the object is in the zone and not filtered
                    if (cv2.pointPolygonTest(current_contour, bottom_center,
                                             False) >= 0
                            and not zone_filtered(
                                obj, self.zone_config[name][camera].get(
                                    'filters', {}))):
                        current_objects_in_zones[name].append(obj['label'])

            ###
            # Draw tracked objects on the frame
            ###
            current_frame = self.plasma_client.get(f"{camera}{frame_time}")

            if not current_frame is plasma.ObjectNotAvailable:
                # draw the bounding boxes on the frame
                for obj in tracked_objects.values():
                    thickness = 2
                    color = COLOR_MAP[obj['label']]

                    if obj['frame_time'] != frame_time:
                        thickness = 1
                        color = (255, 0, 0)

                    # draw the bounding boxes on the frame
                    box = obj['box']
                    draw_box_with_label(
                        current_frame,
                        box[0],
                        box[1],
                        box[2],
                        box[3],
                        obj['label'],
                        f"{int(obj['score']*100)}% {int(obj['area'])}",
                        thickness=thickness,
                        color=color)
                    # draw the regions on the frame
                    region = obj['region']
                    cv2.rectangle(current_frame, (region[0], region[1]),
                                  (region[2], region[3]), (0, 255, 0), 1)

                if camera_config['snapshots']['show_timestamp']:
                    time_to_show = datetime.datetime.fromtimestamp(
                        frame_time).strftime("%m/%d/%Y %H:%M:%S")
                    cv2.putText(current_frame,
                                time_to_show, (10, 30),
                                cv2.FONT_HERSHEY_SIMPLEX,
                                fontScale=.8,
                                color=(255, 255, 255),
                                thickness=2)

                if camera_config['snapshots']['draw_zones']:
                    for name, zone in self.zone_data.items():
                        thickness = 2 if len(
                            current_objects_in_zones[name]) == 0 else 8
                        if camera in zone['contours']:
                            cv2.drawContours(current_frame,
                                             [zone['contours'][camera]], -1,
                                             zone['color'], thickness)

                ###
                # Set the current frame
                ###
                self.camera_data[camera]['current_frame'] = current_frame

                # delete the previous frame from the plasma store and update the object id
                if not self.camera_data[camera]['object_id'] is None:
                    self.plasma_client.delete(
                        self.camera_data[camera]['object_id'])
                self.camera_data[camera]['object_id'] = f"{camera}{frame_time}"

            ###
            # Maintain the highest scoring recent object and frame for each label
            ###
            for obj in tracked_objects.values():
                # if the object wasn't seen on the current frame, skip it
                if obj['frame_time'] != frame_time:
                    continue
                if obj['label'] in best_objects:
                    now = datetime.datetime.now().timestamp()
                    # if the object is a higher score than the current best score
                    # or the current object is more than 1 minute old, use the new object
                    if obj['score'] > best_objects[obj['label']]['score'] or (
                            now -
                            best_objects[obj['label']]['frame_time']) > 60:
                        obj['frame'] = np.copy(
                            self.camera_data[camera]['current_frame'])
                        best_objects[obj['label']] = obj
                        # send updated snapshot over mqtt
                        best_frame = cv2.cvtColor(obj['frame'],
                                                  cv2.COLOR_RGB2BGR)
                        ret, jpg = cv2.imencode('.jpg', best_frame)
                        if ret:
                            jpg_bytes = jpg.tobytes()
                            self.client.publish(
                                f"{self.topic_prefix}/{camera}/{obj['label']}/snapshot",
                                jpg_bytes,
                                retain=True)
                else:
                    obj['frame'] = np.copy(
                        self.camera_data[camera]['current_frame'])
                    best_objects[obj['label']] = obj

            ###
            # Report over MQTT
            ###

            # get the zones that are relevant for this camera
            relevant_zones = [
                zone for zone, config in self.zone_config.items()
                if camera in config
            ]
            for zone in relevant_zones:
                # create the set of labels in the current frame and previously reported
                labels_for_zone = set(
                    current_objects_in_zones[zone] +
                    list(self.zone_data[zone]['object_status'][camera].keys()))
                # for each label
                for label in labels_for_zone:
                    # compute the current 'ON' vs 'OFF' status by checking if any camera sees the object in the zone
                    previous_state = any([
                        c[label] == 'ON' for c in self.zone_data[zone]
                        ['object_status'].values()
                    ])
                    self.zone_data[zone]['object_status'][camera][
                        label] = 'ON' if label in current_objects_in_zones[
                            zone] else 'OFF'
                    new_state = any([
                        c[label] == 'ON' for c in self.zone_data[zone]
                        ['object_status'].values()
                    ])
                    # if the value is changing, send over MQTT
                    if previous_state == False and new_state == True:
                        self.client.publish(
                            f"{self.topic_prefix}/{zone}/{label}",
                            'ON',
                            retain=False)
                    elif previous_state == True and new_state == False:
                        self.client.publish(
                            f"{self.topic_prefix}/{zone}/{label}",
                            'OFF',
                            retain=False)

            # count  by type
            obj_counter = Counter()
            for obj in tracked_objects.values():
                obj_counter[obj['label']] += 1

            # report on detected objects
            for obj_name, count in obj_counter.items():
                new_status = 'ON' if count > 0 else 'OFF'
                if new_status != current_object_status[obj_name]:
                    current_object_status[obj_name] = new_status
                    self.client.publish(
                        f"{self.topic_prefix}/{camera}/{obj_name}",
                        new_status,
                        retain=False)
                    # send the best snapshot over mqtt
                    best_frame = cv2.cvtColor(best_objects[obj_name]['frame'],
                                              cv2.COLOR_RGB2BGR)
                    ret, jpg = cv2.imencode('.jpg', best_frame)
                    if ret:
                        jpg_bytes = jpg.tobytes()
                        self.client.publish(
                            f"{self.topic_prefix}/{camera}/{obj_name}/snapshot",
                            jpg_bytes,
                            retain=True)

            # expire any objects that are ON and no longer detected
            expired_objects = [
                obj_name for obj_name, status in current_object_status.items()
                if status == 'ON' and not obj_name in obj_counter
            ]
            for obj_name in expired_objects:
                current_object_status[obj_name] = 'OFF'
                self.client.publish(f"{self.topic_prefix}/{camera}/{obj_name}",
                                    'OFF',
                                    retain=False)
                # send updated snapshot over mqtt
                best_frame = cv2.cvtColor(best_objects[obj_name]['frame'],
                                          cv2.COLOR_RGB2BGR)
                ret, jpg = cv2.imencode('.jpg', best_frame)
                if ret:
                    jpg_bytes = jpg.tobytes()
                    self.client.publish(
                        f"{self.topic_prefix}/{camera}/{obj_name}/snapshot",
                        jpg_bytes,
                        retain=True)
Ejemplo n.º 3
0
class TrackedObjectProcessor(threading.Thread):
    def __init__(self, config, client, topic_prefix, tracked_objects_queue):
        threading.Thread.__init__(self)
        self.config = config
        self.client = client
        self.topic_prefix = topic_prefix
        self.tracked_objects_queue = tracked_objects_queue
        self.camera_data = defaultdict(
            lambda: {
                'best_objects': {},
                'object_status': defaultdict(lambda: defaultdict(lambda: 'OFF')
                                             ),
                'tracked_objects': {},
                'current_frame': np.zeros((720, 1280, 3), np.uint8),
                'current_frame_time': 0.0,
                'object_id': None
            })
        self.plasma_client = PlasmaManager()

    def get_best(self, camera, label):
        if label in self.camera_data[camera]['best_objects']:
            return self.camera_data[camera]['best_objects'][label]['frame']
        else:
            return None

    def get_current_frame(self, camera):
        return self.camera_data[camera]['current_frame']

    def run(self):
        while True:
            camera, frame_time, tracked_objects = self.tracked_objects_queue.get(
            )

            config = self.config[camera]
            best_objects = self.camera_data[camera]['best_objects']
            current_object_status = self.camera_data[camera]['object_status']
            self.camera_data[camera]['tracked_objects'] = tracked_objects
            self.camera_data[camera]['current_frame_time'] = frame_time

            ###
            # Draw tracked objects on the frame
            ###
            current_frame = self.plasma_client.get(f"{camera}{frame_time}")

            if not current_frame is plasma.ObjectNotAvailable:
                # draw the bounding boxes on the frame
                for obj in tracked_objects.values():
                    thickness = 2
                    color = COLOR_MAP[obj['label']]

                    if obj['frame_time'] != frame_time:
                        thickness = 1
                        color = (255, 0, 0)

                    # draw the bounding boxes on the frame
                    box = obj['box']
                    draw_box_with_label(
                        current_frame,
                        box[0],
                        box[1],
                        box[2],
                        box[3],
                        obj['label'],
                        f"{int(obj['score']*100)}% {int(obj['area'])}",
                        thickness=thickness,
                        color=color)
                    # draw the regions on the frame
                    region = obj['region']
                    cv2.rectangle(current_frame, (region[0], region[1]),
                                  (region[2], region[3]), (0, 255, 0), 1)

                if config['snapshots']['show_timestamp']:
                    time_to_show = datetime.datetime.fromtimestamp(
                        frame_time).strftime("%m/%d/%Y %H:%M:%S")
                    cv2.putText(current_frame,
                                time_to_show, (10, 30),
                                cv2.FONT_HERSHEY_SIMPLEX,
                                fontScale=.8,
                                color=(255, 255, 255),
                                thickness=2)

                ###
                # Set the current frame
                ###
                self.camera_data[camera]['current_frame'] = current_frame

                # delete the previous frame from the plasma store and update the object id
                if not self.camera_data[camera]['object_id'] is None:
                    self.plasma_client.delete(
                        self.camera_data[camera]['object_id'])
                self.camera_data[camera]['object_id'] = f"{camera}{frame_time}"

            ###
            # Maintain the highest scoring recent object and frame for each label
            ###
            for obj in tracked_objects.values():
                # if the object wasn't seen on the current frame, skip it
                if obj['frame_time'] != frame_time:
                    continue
                if obj['label'] in best_objects:
                    now = datetime.datetime.now().timestamp()
                    # if the object is a higher score than the current best score
                    # or the current object is more than 1 minute old, use the new object
                    if obj['score'] > best_objects[obj['label']]['score'] or (
                            now -
                            best_objects[obj['label']]['frame_time']) > 60:
                        obj['frame'] = np.copy(
                            self.camera_data[camera]['current_frame'])
                        best_objects[obj['label']] = obj
                else:
                    obj['frame'] = np.copy(
                        self.camera_data[camera]['current_frame'])
                    best_objects[obj['label']] = obj

            ###
            # Report over MQTT
            ###
            # count objects with more than 2 entries in history by type
            obj_counter = Counter()
            for obj in tracked_objects.values():
                if len(obj['history']) > 1:
                    obj_counter[obj['label']] += 1

            # report on detected objects
            for obj_name, count in obj_counter.items():
                new_status = 'ON' if count > 0 else 'OFF'
                if new_status != current_object_status[obj_name]:
                    current_object_status[obj_name] = new_status
                    self.client.publish(
                        f"{self.topic_prefix}/{camera}/{obj_name}",
                        new_status,
                        retain=False)
                    # send the best snapshot over mqtt
                    best_frame = cv2.cvtColor(best_objects[obj_name]['frame'],
                                              cv2.COLOR_RGB2BGR)
                    ret, jpg = cv2.imencode('.jpg', best_frame)
                    if ret:
                        jpg_bytes = jpg.tobytes()
                        self.client.publish(
                            f"{self.topic_prefix}/{camera}/{obj_name}/snapshot",
                            jpg_bytes,
                            retain=True)

            # expire any objects that are ON and no longer detected
            expired_objects = [
                obj_name for obj_name, status in current_object_status.items()
                if status == 'ON' and not obj_name in obj_counter
            ]
            for obj_name in expired_objects:
                current_object_status[obj_name] = 'OFF'
                self.client.publish(f"{self.topic_prefix}/{camera}/{obj_name}",
                                    'OFF',
                                    retain=False)
                # send updated snapshot over mqtt
                best_frame = cv2.cvtColor(best_objects[obj_name]['frame'],
                                          cv2.COLOR_RGB2BGR)
                ret, jpg = cv2.imencode('.jpg', best_frame)
                if ret:
                    jpg_bytes = jpg.tobytes()
                    self.client.publish(
                        f"{self.topic_prefix}/{camera}/{obj_name}/snapshot",
                        jpg_bytes,
                        retain=True)