License Plate Parser Edge
Extracts and post-processes license plates recognized using the License Plate Recognition - Edge AI Model
Overview
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
Properties
Property | Value |
---|---|
display_info | If true, LPR info will be drawn on video. ex. true / false |
objects_to_associate | Objects 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: car.red object_label.* : any object of this type that has at least one classifier attribute. Example: car.* (this will match car.red , car.yellow , etc) |
detection_buffer | Time (in seconds) that the License Plate must be present before reporting results in metadata. ex. 1.0 |
rejection_buffer | Time (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
Metadata Property | Description |
---|---|
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 ) |
"nodes":{
"annotate_lpr_edge*":{
"type":"annotate_lpr_edge",
"license_plates_entered_delta":"<int>",
"license_plates_exited_delta":"<int>",
"license_plates_count":"<int>",
"license_plates":{
"<object_tracking_id>": {
"plate":{
"type":"Plate",
"score":<float>,
"props":{
"plate":[
{
"value":"<license_plate_number>",
"score":<float>
}
]
}
}
}
}
}
}
Format
Key | Type | Description |
---|---|---|
license_plates_entered_delta | Integer | Number of new license plates detected since last frame |
license_plates_exited_delta | Integer | Number of license plates that left since last frame |
license_plates_count | Integer | Total number of license plates in the view right now |
license_plates | List of object IDs | Information about each detected and recognized license plate.object_tracking_id : Unique identifier for a specific object, as specified by object.id property (see Track Objects NodePlease 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 |
---|---|---|
10400 | The 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,
}]
}]
Updated 2 months ago