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Detecting emergency vehicles

Watcher can detect emergency vehicles including police cars, fire trucks, ambulances, etc. This function may be useful if you are using Watcher for opening a gate, and you want emergency vehicles to pass through the gate freely.

The emergency vehicle detection is a part of license plate recognition (LPR) module but is disabled by default since recognizing emergency vehicles requires more VRAM than simple LPR. Please refer to Calculating video memory for analytics for details on the resources consumption.

Video image requirements for emergency vehicle detection are the same as those for standard license plate recognition.

Enabling the detection of emergency vehicles

To enable the detection of emergency vehicles:

  1. Install and configure the LPR module.

  2. Open the /etc/flussonic/flussonic.conf file on the recognizing streamer to add ssd_net_path /opt/flussonic/lib/vision/priv/ssd_wcar; option in the plugin vision section:

    plugin vision {
        ssd_net_path /opt/flussonic/lib/vision/priv/ssd_wcar;
  3. After saving the configuration file, run the command to apply the changes:

    service flussonic restart

Browsing and searching for emergency vehicles

The detected emergency vehicles are included in the general list on the Events -> License plates tab.

Emergency vehicle detected

To search for events of emergency vehicle recognition, you can use an API request like GET http://WATCHER-IP/vsaas/api/v2/analytics/license_plates with the event_type=emergency parameter.


curl -v GET -H 'x-vsaas-api-key: 7c75da8fb314183f1f825271898a3687' \
-d 'limit=12&offset=12&event_type=emergency' \
-H "Content-Type: application/x-www-form-urlencoded;charset=UTF-8" \ 

Put your own API key to the x-vsaas-api-key parameter or use another way to authorize the API request.