Number Plate Recognition

Number plate recognition detects and reads license plates on vehicles.

Configuration Parameter Description
Boldness The boldness setting to use for detecting the edges of characters.
ExpectedRotation The expected amount of rotation (from horizontal, in degrees) for a number plate in the scene.
FreeformRegion The Region of Interest (ROI) to monitor for number plates, if the ROI is not rectangular.
Input The image track to process.
Location The location(s) for which you are reading number plates.
LocationWithPriorities The locations for which you are reading number plates, and their relative priorities.
MaxCharHeight The maximum height of the main characters on the number plate.
MaxInputQueueLength Can be used to place a limit on latency.
MaxPlatesPerFrame The maximum number of number plates that you expect to appear in a single image or video frame.
MinCharHeight The minimum height of the main characters on the number plate.
MinRead The minimum number of consecutive frames in which a number plate must be visible before a result is generated.
MinValidScore The average character score required for a number plate to be recognized.
NumParallel The maximum number of video frames to analyze simultaneously.
OutputAlternativeResults Specifies whether to return all results, when integration returns more than one result, all for the same plate in the image.
OutputUnformattedResults Specifies whether to include unformatted results in the output. These are results where the number plate exceeds the confidence score specified by MinValidScore, but does not match one of the expected formats.
Region The Region of Interest (ROI) to monitor for number plates.
RejectReadsWithInvalidGaps Specifies whether to reject number plate reads with gaps in the wrong place.
SampleInterval The interval at which frames are selected to be analyzed.
SegmentDuration The maximum duration of a record in the SegmentedResult or SegmentedResultWithSource track.
Sensitivity The confidence level required to detect a number plate.
Type The analysis engine to use. Set this parameter to NumberPlate.

Output Tracks

The following table describes the tracks that are generated by this engine. The Output column indicates whether the information contained in the track is included by default in the output created by an output task (when you don't set the Input parameter for the output task).

Output track Description Output
Data Contains one record, describing the analysis results, per detected number plate, per video frame. No
DataWithSource

The same as the Data track, but each record also includes the source frame.

No
Result Contains one record, describing the analysis results, for each recognized number plate. When the same number plate appears in many consecutive frames, Media Server produces a single result. Yes
ResultWithSource

The same as the Result track, but each record also includes the best source frame.

No
SegmentedResult

(Available only when processing video). The same as the Result track, except the duration of each record is limited by the parameter SegmentDuration. If a result exceeds the specified duration, Media Server begins a new record with the same ID.

Yes
SegmentedResultWithSource

(Available only when processing video). The same as the ResultWithSource track, except the duration of each record is limited by the parameter SegmentDuration. If a result exceeds the specified duration, Media Server begins a new record with the same ID.

No
Start

The same as the Data track, except it contains only the first record of each event.

No
End

The same as the Data track, except it contains only the last record of each event.

No

For more information about number plate records, see Number Plate Recognition Results or use the action GetExampleRecord.