Topics in this article:
- Camera Positioning and Zooming
- Night Time Adjustments
- Naming and Labeling
- Saving a License Plate
- Searching
- Recent Sightings
- License Plate Alerts
- Add Licenses Plates
- Bulk Adding License Plates
- Helpful Links
- Contact Support or Sales
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 key offset angles to keep in mind when setting up LPR:
1. The first angle offset is the angle between the direction to the sky and the direction of the car from the perspective of the camera. This "offset angle" should be between 5 and 30 degrees.
2. The second angle offset is the angle between the imaginary line from the license plate to the camera and the imaginary line from the license plate parallel with the ground. This "offset angle" should be between 15 and 30 degrees.
Lastly, the framing of the vehicle is a key factor in accurate detection. In an ideal set-up, the vehicle should take up approximately 1/3 to 1/2 of the frame where the license plate has a minimum of a 100-pixel width. This can be accomplished with effective mounting or adjusted with digital and motor zooming. For more information on how to adjust the device zoom in the console, please see the article here.
Night Time Adjustments
When setting up the ideal environment for LPR, we have to take into account lighting.
For reducing blur and detecting readable license plates at night, faster shutter speeds are required. The specific shutter speed will vary depending on the environment but we recommend setting the slowest speed to 1/60 of a second (if blur is still present please contact support to make some custom image settings). This will allow the cameras to reduce glare from headlights and therefore, reduce missed sightings.
When the device is adjusted for higher shutter speeds, less light gets picked up by the camera. We recommend adding additional lighting to the field of view to accommodate higher shutter speeds. This light should ideally face the vehicle head on to avoid any complications from a backlit subject. This additional lighting should be bright enough to ensure that vehicle visibility from the camera is in-line with what is picked up during the day-time.
Naming and Labeling
- Navigate to the "Investigations" tab on the left hand side.
- Click on the "License Plates" tab across the top.
- Navigate between "Recent Sightings" and "Saved License Plates" based on need.
Saving a License Plate
Saving a license plate means you are building a license plate profile.
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1. Click on the "Pencil" icon next to where it says "Unnamed" underneath the license plate thumbnail. |
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2. Enter in the license plate name and click "Save". |
Searching
To search for a license plate number, 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.
- Select Labels - Labels that have been created for groupings, such as service trucks etc.
- Select Cameras - Filter by vehicles picked up by a specific camera.
- Select Locations - LPR events captured at a specific location.
- Past 7 Days - Filter by LPR events that have occurred in a specific date range.
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 an LPR event.
Adding a Label
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 of your choosing.
Sighting Details
When you hover over the thumbnail of a particular plate, more information about the sighting appears:
Details
This provides a more detailed snapshot of the LPR event, along with an option to go to the footage.
If the plate is already saved you can search for it in the "Saved License Plates" tab and click 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.
All Sightings
This allows you to see all the events created for a specific plate. You can filter to a specific date range on this page.
Not a Plate
If an image is not of a license plate, selecting this will immediately remove this from the "Recent Sightings" tab and send the feedback to the system when looking for plate events in the future.
License Plates Alerts
- To set up License Plate Alerts, first create an Alert Policy.
- Select the License Plate Event to be added to the alert policy. Once it's been added with a time schedule, you will be presented with the following options:
- Alert if Spotted: If you would like to receive alerts only for specific vehicles, you can assign labels to their saved plates and utilize the "Alert if Spotted" section of the above alert policy module.
- Alert for License Plates other than: If you would like to receive alerts for all vehicles except for specific types, you can assign labels to these saved exception plates and utilize the "Alert for license plates other than" section of the above alert policy module.
- Alert for any Unsaved License Plates: If you would like to be alerted every time a vehicle drives by with an unsaved license plate, you can toggle on the "Alert for any unsaved license plates" feature of the above alert policy module.
Add License Plates
| 1. On the License Plates tab of the Investigations page, click the “Add License Plates” button on the top right of the screen. | |
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2. You'll see a modal pop up to enter the name of the license plate you want to save, the license plate alphanumeric digits, and an optional label. |
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3. Click "Submit". It will populate 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!
Helpful Links
Contact Support or Sales
Have more questions? Contact Rhombus Support at +1 (877) 746-6797 option 2 or support@rhombus.com.
Interested in learning more? Contact Rhombus Sales at +1 (877) 746-6797 option 1 or sales@rhombus.com.
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