License Plate Parser Edge

Extracts and post-processes license plates recognized using the License Plate Recognition - Edge AI Model


This node parses the output of "License Plate Recognition" model to extract the license plate information.

This node requires AI Model Node (Vehicle Detection model) -> Model Inference Node (License Plate model) -> Track Objects Node -> Model Inference Node (License Plate Recognition) prior to it in order to function properly.

Inputs & Outputs

  • Inputs : 1, Media Format : Raw Video
  • Outputs : 1, Media Format: Raw Video
  • Output Metadata : None


display_infoIf true, LPR info will be drawn on video.

ex. true / false
objects_to_associateObjects classes that should be considered on the LPR and vehicle association.

ex. car, vehicle, truck

Accepted formats:
object_label: any object of this type, with or without a classifier attribute. Example: car

object_label.class_type: any object of this type that has a specific classifier attribute. Example:

object_label.*: any object of this type that has at least one classifier attribute. Example: car.* (this will match, car.yellow, etc)
detection_bufferTime (in seconds) that the License Plate must be present before reporting results in metadata.

ex. 1.0
rejection_bufferTime (in seconds) during which objects that leave and re-enter the scene will be ignored. Increase to reduce duplicate alerts for a given object.

ex, 5.0


Metadata PropertyDescription
nodes.<node_id>License plate information as described in the JSON below.

<node_id> for License Plate Detection Nodes is of the form annotate_lpr_edgeX (ex. annotate_lpr_edge1)
            "<object_tracking_id>": {


license_plates_entered_deltaIntegerNumber of new license plates detected since last frame
license_plates_exited_deltaIntegerNumber of license plates that left since last frame
license_plates_countIntegerTotal number of license plates in the view right now
license_platesList of object IDsInformation about each detected and recognized license plate.

object_tracking_id : Unique identifier for a specific object, as specified by property (see Track Objects Node

Please check the json example for more details.

Objects metadata augmentation

The following information is added to the detected object's "attributes" array:

"class_id" field"label" field"probability" field
10400The recognized license plate (string)LP recognition confidence
"objects": [{
    "id": 5750484150146564100,
    "label": "car",
    "class_id": 0,
    "probability": 0.98,
    "rect": {
        "width": 47,
        "top": 201,
        "left": 656,
        "height": 25.
    "attributes": [{
        "label": "ABC1234",
        "class_id": 10400,
        "probability": 1.0,