The License plate recognition parameters. The Administrator client

Frames per second.

fps

float

Actual

[1, 30]

A video is processed at a certain number of frames per second.

A minimum object size.

min_obj_size

float (in pixels)

50.0

[0, 512]

A minimum size of the object being recognized (in pixels). The size of the object is determined by the length of its diagonal.

A minimum object width.

min_obj_rel_width

float

0

[0, 1]

The minimum relative width of the object being recognized.

A minimum object height.

min_obj_rel_height

float

0

[0, 1]

The minimum relative height of the object being recognized.

A minimum size of unrecognized objects.

motion_min_scale

float

2.0

[1, 4]

The minimum value at which previously unrecognized objects are searched for.

Time to resume searching for objects.

motion_cooldown

float (in seconds)

1.0

[0, 4]

Time required to resume searching for new objects in the same vision area (in seconds).

A low threshold for an object recognition.

weak_obj_score_threshold

float

0.4

[0, 1]

The lowest threshold to estimate an object recognition. If the value is lower than the threshold value, the objects are discarded and aren’t considered for further recognition.

A minimum threshold value for an object recognition.

strong_obj_score_threshold

float

0.8

[0, 1]

A minimum threshold value for an object to be detected.

An area size for re-detection.

glance_expansion

float

3.5

[1, 5]

Defines an area size for re-detection of the tracked objects. Large values may increase tracking of fast-moving objects, but it can also lead to missed object detection due to smaller relative size of objects in the detection area.

Event processing time.

aggregation_time

float

0.5

[0, 10]

The time, measured in seconds, during which the best captured image is selected for object recognition. Larger values of the parameter increase the recognition quality but also increase the time required for an event generation.

Unique characteristics of the objects to generate an event.

lev_distance_threshold

float

1.0

[0, 2]

Defines the degree of uniqueness required between two recognition results to trigger separate recognition events.

A track time of an object.

track_lifetime

float

2.0

[1, 10]

A track time of an object that is measured in seconds and doesn’t include new events.

A similarity threshold of the objects.

tracking_similarity_threshold

float

0.3

[0, 1]

The minimum similarity of objects at which an object can be considered a continuation of the track. Lower values can improve stability, but unrelated objects can be grouped into one track.

A minimum low quality threshold of a frame.

low_quality_threshold

float

0.5

[0, 1]

A minimum low-quality threshold value of a frame to be acceptable for recognition.

A recognized car plate persistency time.

recognized_plate_persistency

float

10.0

[0, 300]

The time, measured in seconds, during which the persistence of the recognized car plate is active and prevents the duplication of events.

An event generation interval for a static object.

recognized_plate_report_interval

float

30.0

(0, 600]

The time, measured in seconds, during which a new event ins’t generated for the recognized car plate that is still in the field of view.

A maximum number of objects under recognition.

tracked_objects_limit

int

32

(0, 512]

The maximum number of objects under simultaneous recognition. If the limit is exceeded, only the largest objects are saved.