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Adding ANPR

by Benchmark

ANPR is a beneficial technology which is too often overlooked when designing systems for private sector commercial and industrial sites. Often considered the exclusive preserve of law enforcement and Government agencies, ANPR technology can add much value to a number of applications by delivering vehicular access control during working hours while capturing vehicle details when the site is secure. The use of ‘open platform’ devices also makes adding ANPR to a smart system a simple and easy task.

When thinking about the role of ANPR (automatic number plate recognition), most people think about law enforcement and Government agencies using a system linked to the DVLA database to identify wanted individuals, suspicious vehicles and other known miscreants. Of course, this is one role that ANPR technology is ideal for, and it has been proven to be very effective for such tasks.

It could be argued that the success of ANPR, when utilised in this manner, has led to a somewhat blinkered view of its potential for other applications. Part of this might also be due to the costs of such systems. Of course, if deployed in commercial and industrial applications for a variety of management purposes, those costs fall significantly. Indeed, in today’s market of smart cameras, ANPR at the edge can be very cost-effective indeed.

In order to better understand the potential on offer, it is best to consider ANPR – and more specifically the users’ vehicle number plates – as an access control credential. When a known vehicle is detected during hours for which it has access permissions, its presence can be used to automatically open gates and barriers. It is true that approaching vehicles may contain several persons, but the ANPR is only granting access to a car park, depot or approach road, and as such represents one part of a solution.

There are a number of possible variations. Contractors’ or suppliers’ vehicles can be directed to relevant areas, deliveries or collections can be scheduled out of hours, known visitors can be granted access whilst their host is notified of their arrival, or vehicle details can simply be archived to create an access log.

While the benefits of ANPR are impressive, it is important that installers and integrators check camera positioning instructions from ANPR application suppliers. ANPR relies upon capturing the numberplate, typically the front facing one, of a vehicle. Number plates are standardised with regards to font size and shape, but variations do exist. Whilst most vehicles will have the number plate located centrally on the lower part of the front of the vehicle, there will be exceptions.

The successful deployment of ANPR systems must ensure that considerations are made for camera mounting height and angle, field of view, potential issues with headlights at certain times of year, etc.. It is also important to consider how any false rejects or false accepts will be dealt with.

Everyday video processing – compression, automatic gain control, digital noise reduction, image enhancement – can all impact on the information that the ANPR algorithm is analysing. Testing in situ is often the only way to get a good understanding of how the combination of any selected camera and edge-based application will work.

Adding ANPR

Axis Communications, the image capture partner in the Benchmark Smart Solutions project, takes an ‘open platform’ approach with its cameras via the ACAP (Axis Camera Application Platform) programme.

ACAP is supported by the majority of the company’s network camera and encoder range. It allows edge applications to be added to devices, enhancing the integration possibilities. Edge-based applications can be used for standalone solutions using a single camera, or can be deployed across a system.

By working with accredited partners, Axis Communications can ensure that all edge-based applications are compatible with the devices. This allows installers and integrators to be assured that any integrations will be seamless and credible.

There are a number of ANPR partners, allowing different approaches to be taken. Some use cloud-based remote servers to carry out the processing, while others implement all processing at the camera. Where they may be a need to independently interrogate the ANPR records, a dedicated viewer can be used to allow report inspection without logging into the camera configuration screens.

Axis will allow the generation of a trial licence for any of the edge applications, so it gives installers and integrators a chance to inspect the various options before making a specification.

Installing the applications is very simple. These typically are a single .eap file which is uploaded to the camera via its Applications menu. With the camera connected, simply browse to the .eap file on the connected server and upload.

Once this process has completed the edge application will appear in the Applications list; it will show as ‘Stopped’ with the license as either ‘Missing’ or ‘Invalid’. If you then browse to the Axis website you can request a trial licence. Simply enter the camera’s serial number, select the product you wish to trial and a link gives a downloadable file.

Once the file has been downloaded, simply select the edge application in the camera (you might get an error message but ignore this) and select the Licence option. Then browse to the relevant file, upload it and the edge application will become operational.

Configurations will very much depend upon the edge application chosen, but once you have worked through these there will be a need to monitor the performance of the edge application for a while to ensure the set-up is delivering the expected results.

In order to control gates or barriers, there are a few options. The first is to manage the camera and edge application via a VMS, such as Milestone Systems’ XProtect series. Using the Rules engine will allow gates and barriers to be triggered. The Rules will also filters to be applied, such as only allowing ANPR triggers to be active according to a schedule. It will also allow ANPR events to trigger other devices, such as a camera in a loading bay area to monitor deliveries if the vehicle is logged as a supplier, for example.

Another option is to use the VMS to link the Axis camera and edge application with an access control system. This can be linked to the XProtect family of VMS packages via a direct integration using the XProtect Access Control module.

It is also possible to take control via an access control front end if the camera or even the VMS has been integrated with its software. This is very easy to achieve and is arguably one element of many leading access control systems which is underutilised.

Finally, it is possible to link the camera to an AXIS 1001 controller to automate a gate or barrier.

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