Control4 APNR / ALPR

Image URL

If the camera you are integrating with has a Control4 driver click on the Control4 driver and go to the Camera Test Tab and then click the button Get Snapshot URL and copy that URL into the ANPR drivers Image URL property box. If you do not have a Control4 driver for the camera you are using you will most likely need to search online to find the URL for the snapshot image. This is not just the cameras IP but the IP combined with a complete URL structure that goes directly to the snapshot image. 

Authorization Required?

For authorization, that is normally required. You can test whether it is by visiting the URL in an incognito browser window and seeing if you are prompted for a username and password. If you are then you need to carry on filling the next settings out. If you aren’t the following settings can be left blank or as their default values.

Authorization  Type

The authorization type can be either Basic or Digest. You should try both and see which one works for you. You can also check this if you have a driver for the camera installed on Control4. The camera driver properties will show you what is being used for your camera – Basic or Digest.

Username & Password

If you visit the URL in the incognito browser window and need to enter a username and password please enter the correct ones in these fields.

To test whether the driver is working go to the actions tab in Composer and press Test Image Capture. Then go to the lua tab and have a look at what is outputted. It will seem like gibberish but it is the Base64 representation of what the driver finds using the details you entered.

https://base64.guru/converter/decode/file

You should visit the above link and paste in the Base64 text. Once you press “Decode Base64 to File” you should see the image if you have entered everything correctly. If you don’t see the correct image then you should look at what is outputted and update the properties.

If issues persist please contact me at shivam@shivampaw.com

You now need to get the API key for OpenALPR. This process is shown in the video opposite. You then need to enter the API key in the Driver Properties. You must also choose a region. The available regions and their region code are shown in the driver documentation.

Once the key and the region are entered you can go to the driver actions and press Test Image Capture and Plate Detection. If you then look at the Lua output you will find the results of the detection. If you don’t see any output then set your Log Level to 3 – Info and Log Mode to Print.

The driver includes two variables: License Plate and Confidence Level. The License Plate will contain the license plate detected in the last image. This will be an uppercase string with NO spaces. The Confidence Level will be a float number between 0 and 100 showing the confidence level of the recognition.

The driver itself has a programming event called License Plate Detected. This will fire when a license plate has been detected. At this point, you can use the variables to program something to happen. For example, if the License Plate is “AB12CDE” then Open the gate and turn on a room light.

The driver contains a programming action that must be used to trigger the fetching of an image and detection of a plate. The action is called Fetch Image And Detect License Plate. You would normally trigger this action when motion is detected on a sensor or an active beam sensor is broken.

The driver also supports push notification attachments. In the Push Notifications agent you can choose an attachment and this driver has an option to send the last recorded image as a push notification. The image is only updated when a License Plate is detected. If no plate is detected no image is set.