← Back to Articles

License plate recognition in videosurveillance program Xeoma

The License plate recognition module (also called ANPR) is available in Xeoma’s PRO version. The system includes algorithms of actions that allow us to recognize a license plate of an approaching vehicle by analyzing the video from the cameras.

Our own module supports a large number of countries, allows you to create lists of license plates, generate events, on a basis of which you can allow opening the barrier, turn on the light, etc.

Our own algorithms will provide good recognition quality in day and night hours in a wide range of weather conditions, as well as let you set the necessary system’s reactions for the recognition. The recognition quality is over 98% (if you follow the recommendations). You may also use the recognition by individual frames without using the video stream. The database saves the data about the date and time of the car detection. Simultaneous support for several checklists of license plates. There is the opportunity to save and view the video stream from multiple cameras synchronously.

Operational schemes: сapture, identification and saving license plates in the database with or without verification.
Comparing the captured license plates with the existing database in online mode in order to identify coincidences.
Search for license plates in the archive according to the given license plate.
License plate verification – the process of comparing the captured license plate on the video record to the given license plate.

Why do we need license plate recognition system?

With the license plate recognition system you can easily automate the entry to the any enterprise territory. You no longer need to issue passes for customers and monitor if anyone has lost it. Your car license plate is your pass.

This system will allow you to control the number of vehicles on the territory. Driving in and out cars control will strengthen the security. Database will consist of “white” and “black” lists, it will help you to identify the intruder. Such system, implemented on the company territory, will provide control over the personnel and vehicles movement on its territory. Nobody will be able to enter the service area, as well as leave it without your permission. License plate recognition system can be implemented at gas stations, service stations, as well as to monitor transport conditions.

How does license plate recognition work in Xeoma videosurveillance?
You simply add the “License plate recognition” module (ANPR module) to the chain, as it is shown on the picture:

In the module settings specify the detection area. You can also specify the undetectable zones, for example, curbs or sidewalks. If you do not specify the search area, then Xeoma will analyze the full frame.

Specify the detection area in the ANPR module

In the “License plate recognition” module you can specify the needed settings, for example, 
Detection type:
– detects white list cars (the archive will be written only with license plates from the white list);
– detects cars not in white list(the archive will be written only with license plates not from the white list (the ones in the white list – will be ignored));
– detects any cars (the archive will be written with any license plates);
– detects absence of cars (the archive will be written only with segments in which there is no license plates);
– detects always (the archive will be written continuously);
– detects upon receiving signal from external third-party utility/URL (when you receive an http-request (field “Path/URL to the external module”) segment will be written to the archive.

Choose the needed detection type in

You can choose the angle at which to display information about and picture of the car license plate, as well as the display time (2 sec., 10 sec., 1 min. and etc.).

Choose where to show the information about and picture of the car license plate
When detecting, the program records video frame with the detected vehicle and its license plate:

How information is shown when ANPR module is in use

You can also write data to the cvs-reports (get them on the server in the settings folder (reports folder): 

For Windows it’s:
C:\Users\Public\Documents\Xeoma\ (either if Xeoma is installed or not installed)

For Linux:
/home/USERNAME/.config/Xeoma/ (not installed)
/usr/local/Xeoma/ (installed)

For Mac OS X:
Users/USERNAME/Xeoma/ (not installed)
Users/Shared/Xeoma/ (installed)

This is how the cvs-reports will look like:

CVS reports from ANPR module in Xeoma videosurveillance

Integration with external systems:

Xeoma modules can be easily synchronized with external systems and devices. For example, you have your own database and you want the number plates detected by Xeoma to be checked if they are/aren’t from your database. After the plates are checked, destination modules will/will not start working (depending on your settings).

If you want to synchronize ANPR in Xeoma with an external system, you need to configure data transfer to HTTP Server. It can be done in 2 simple steps:

1. Open the ANPR module’s settings and choose “Detect upon receiving signal from external third-party utility/URL” as a detection type.

Detection type settings in ANPR module.

2. Then enter the external script’s URL (it can be e.g. CGI-script) into the “Path/URL to an external module” field in ANPR module’s settings.

Specify the external script's URL to complete the integration.

By using {NUMBER} macros information about the recognized license plate will be passed to the external module as a parameter. You can also specify static parameters (not macros) there.

After the data transfer is configured, each time the module is triggered information about the detected license plate number will be passed to HTTP Server via URL parameter.
E.g. if the license plate number detected by Xeoma is found in the external database, integration is set to start recording into Archive for the time specified in the settings of Postrecord (see Image 1).
I.e., the scheme is: Xeoma detects a license plate number → a command is being sent to HTTP Server → Server replies with e.g. 0 or 1 (0 – there’s no record to Archive, 1 – recording for 3 seconds (see Postrecord settings) is enabled).

If everything is done correctly, ANPR will be synchronized with external systems and devices.

Ways to increase the successful recognition rate:

  • Point the camera in the direction of vehicles, facing license plates at right angle;
  • Fasten the camera to minimize wind interferences, vibrations, etc.;
  • Place the camera so that a license plate would take most of the frame;
  • Use proper lightning in the low-light circumstances (for example, an IR projector);
  • Use long-focus objective;
  • Set exposure to a minimum;
  • Turn auto focus off.

15 September 2015