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filter dedicated LPR plates before creating the event (#23977)

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Josh Hawkins 2026-08-13 06:44:31 -05:00 committed by GitHub
parent aff9799451
commit c70a0802b8
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1 changed files with 37 additions and 21 deletions
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58
frigate/data_processing/common/license_plate/mixin.py
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@ -1172,6 +1172,28 @@ class LicensePlateProcessingMixin:
return rep["plate"], rep["conf"], rep["char_confidences"], rep["area"]
def _passes_plate_filters(self, camera: str, plate: str) -> bool:
"""Check a plate against the configured length and format filters."""
if len(plate) < self.lpr_config.min_plate_length:
logger.debug(
f"{camera}: Filtered out plate '{plate}' due to length ({len(plate)} < {self.lpr_config.min_plate_length})"
)
return False
if self.lpr_config.format:
try:
if not re.fullmatch(self.lpr_config.format, plate):
logger.debug(
f"{camera}: Filtered out plate '{plate}' due to format mismatch"
)
return False
except re.error:
logger.error(
f"{camera}: Invalid regex in LPR format configuration: {self.lpr_config.format}"
)
return True
def _generate_plate_event(self, camera: str, plate: str, plate_score: float) -> str:
"""Generate a unique ID for a plate event based on camera and text."""
now = datetime.datetime.now().timestamp()
@ -1511,10 +1533,14 @@ class LicensePlateProcessingMixin:
plate_id = None
for existing_id, data in self.detected_license_plates.items():
# entries from the object pipeline on this camera have no
# last_seen until they pass the filters below
last_seen = data.get("last_seen")
if (
data["camera"] == camera
and data["last_seen"] is not None
and current_time - data["last_seen"]
and last_seen is not None
and current_time - last_seen
<= self.config.cameras[camera].lpr.expire_time
):
similarity = JaroWinkler.similarity(data["plate"], top_plate)
@ -1525,6 +1551,11 @@ class LicensePlateProcessingMixin:
)
break
if plate_id is None:
# the event id doubles as the cluster key, so a plate rejected
# after this point would leave an entry that never expires
if not self._passes_plate_filters(camera, top_plate):
return
plate_id = self._generate_plate_event(camera, top_plate, avg_confidence)
logger.debug(
f"{camera}: New plate event for dedicated LPR camera {plate_id}: {top_plate}"
@ -1569,27 +1600,12 @@ class LicensePlateProcessingMixin:
f"{camera}: Clustering changed top plate '{top_plate}' (conf: {avg_confidence:.3f}) to rep '{rep_plate}' (conf: {rep_conf:.3f})"
)
# Apply length and format filters to the clustered representative
# rather than individual OCR readings, so noisy variants still
# contribute to clustering even when they don't pass on their own.
if len(rep_plate) < self.lpr_config.min_plate_length:
logger.debug(
f"{camera}: Filtered out clustered plate '{rep_plate}' due to length ({len(rep_plate)} < {self.lpr_config.min_plate_length})"
)
# filter the clustered representative rather than individual OCR
# readings, so noisy variants still contribute to clustering even
# when they don't pass on their own
if not self._passes_plate_filters(camera, rep_plate):
return
if self.lpr_config.format:
try:
if not re.fullmatch(self.lpr_config.format, rep_plate):
logger.debug(
f"{camera}: Filtered out clustered plate '{rep_plate}' due to format mismatch"
)
return
except re.error:
logger.error(
f"{camera}: Invalid regex in LPR format configuration: {self.lpr_config.format}"
)
# Update stored rep
self.detected_license_plates[id].update(
{