Managing License Plate Recognition (LPR)

Topics in this section include:

• Camera Positioning and Zooming
• Naming and Labeling
• Saving a License Plate
• Searching
• Recent Sightings
• License Plate Details
• License Plate Alerts
• Add Licenses Plates
• Bulk Adding License Plates

License Plate recognition does not come enabled by default. To enable it, make sure you have assigned an enterprise license to the camera you want to capture license plates with. You can learn how to enable this feature by reading the Enabling Features section here. 

Camera Positioning and Zooming

You can increase the accuracy of the license plate recognition software by ensuring that the distance between the camera and where the license plates are within the recommended distances. 

To see the full distance table, you can refer to the article here. 

Camera positioning is very important for LPR performance. The most significant positioning factor is angling. There are two keys angles to keep in mind when setting up LPR: the horizontal offset and the vertical offset. When thinking about both of these values, the less angle the better. 

The horizontal offset is the angle between the direction to the sky and the direction of the car from the perspective of the camera. This "pitch angle" should be between 5 and 30 degrees. 

The vertical offset is the angle from the license plate to the camera. This "pitch angle" should be between 15 and 30 degrees.

You can also adjust the digital zoom level, explained in the article here and the motor zoom for the R400/R500.

Naming and Labeling

To get to the License Plates feature, go to the Investigations tab, then click on 'License Plates'. 

Saving a License Plate

Saving a license plate means you are building a license plate profile. To save a license plate, you simply have to name it. 

Find the license plate you want to name, and click on the pencil icon and enter the license plate name

Searching

To search for a license plate number, simply use the search bar located in the top left area of the page. You can also type in a partial license plate and all relevant license plates will show up in the results area. 

For searching and matching license plates to saved vehicles for alerting, the software uses fuzzy searching which allows up to 3 characters to mismatch depending on length of the read plate. So even if the software can't identify all the the characters in the plate, it will still show and alert on the correct plates. 

Other search filters are also available to narrow down or expand the time frame that you want your results to be. 

Recent Sightings

The Recent Sightings tab will show you thumbnails of license plates that were recently captured. Here you can perform a variety of actions, such as naming thumbnails to be saved to your organization, and adding label(s) to it. Adding a label is crucial to setting up an alert for specific plates. You can add multiple labels by clicking on the Add label button and entering a label name of your choosing.

As an example from the screen shot above, I added a name 'test1' and a label 'trusted' to the first plate from the left:

When you click on the thumbnail of a particular plate, more information about the sighting appears. From here you can go directly to the footage and view the clip, or view more details about the plate and setup alerts, and mark it as trusted.

License Plate Details

License plate details are located in the popup after you click on the thumbnail in the results area, or if the plate is already saved you can search for it in 'Saved License Plates' tab and click on the thumbnail. You will see some information such at the date and time, the name of the cameras that picked up the license plate, and the location name. 

You will also have an option to go to the footage, which will take you directly to a 30secs clip of the event.  

License Plates Alerts

If you setup an alert on any license plate, any time that plate is spotted an alert (email, push notification, etc) will be sent to all people that have alert notifications turned on. You can setup an alert policy (below) to manage which plates to be notified about via labeling, or to be notified about any unsaved plates:

Add License Plates

On the License Plates tab of the Investigations page, you will see the “Add License Plates” button on the top right of the screen. You'll see a modal pop up to enter the name of the license plate you want to save, and the license plate alphanumeric digits. 

Once you are done, click Submit and you should see it listed in the 'Saved License Plates' tab. 

Bulk Adding License Plates

You can bulk-add license plates on the Rhombus Web Console. To start you must have a CSV file where the data is in the following format:

name,plate,labels(optional) as the headers

Without labels:
name,plate
Example Name,RHOMBUS

With labels:
name,plate,labels

Example Name,RHOMBUS,[Trusted]

Note: License plates need to be 7 alphanumeric characters long (expanded functionality coming soon)

Once you have a CSV in the above format, log in to the console and navigate to the saved license plate page. Next, click the "Bulk Add License Plate" in the upper right.

A pop-up window will appear and you now you can upload the CSV file by clicking the Choose File button. 

Select the file:

Hit the upload button:

Refresh your browser window and then you will see the uploaded data!

If you have any further questions please reach out to our Rhombus Support at help@rhombus.com. If you would like to talk to a Rhombus Sales Representative please reach out to sales@rhombus.com.