License plates
License-plate recognition reads plate numbers from vehicles. It builds on object detection: a vehicle is detected, then its plate is located and read by OCR. Enable an AI backend with license-plate support on the camera. If the camera detects objects itself without reporting where they are (many Reolink models), enable Object Assist so plates get a proper crop.
Setup
In the backend's plugin settings, license plates use two models, a detector that finds the plate and an OCR model that reads the characters. camera.ui downloads them automatically. Both confidences are set on the camera.
Finding a plate and reading it are two jobs, so Settings → Detection has one confidence for each, plus a length filter:
- Plate detection. Plates found with less confidence than this are not read at all (0 to 1, default 0.3).
- Plate reading. Readings the OCR is less sure about than this are ignored (0 to 1, default 0.9).
- Min. plate length. Readings shorter than this are dropped as fragments (default 4 characters).
Where plates appear
A read plate is attached to its vehicle as an attribute. You'll find it:
- On the event, alongside the vehicle.
- In Recordings, where you can filter by the License plate attribute or search for a specific plate.
- In notifications and AI descriptions, for example "Plate ABC-123".