All
About Speed Cameras
Both your modern day car and even your local town and city roadsides lay host to an astonishing array of technological innovation. From simply turning your wheels, to the latest and greatest GPS system, to emissions controllers and safety features- the automobile industry has embraced electronics and microchips – isn’t it time you knew a little about them and what they do?
That’s
why we’re starting a regular column Tech-Talk! to demystify the more technical
side of motoring for our visitors. And to kick it off we’re going to look
outside your car and onto the streets. We’re going to look at one of the
most recent and important advances in traffic policing and identification –
ANPR technology, or to you and me: Automatic Number Plate Recognition.
What is ANPR?
As the name suggests ANPR technology can automatically identify your vehicle
on the road at any time of day, wherever it has been set up for use. Although
specialist ANPR cameras are available to the authorities, it may surprise you
to learn that ANPR can also be applied to almost any existing closed-circuit
television or speed camera apparatus.
An ANPR camera is capable of scanning one number plate per second and can identify you at a speed of up to 100mph, these figures have already increased rapidly and are very much set to continue rising dramatically in the future as both camera and computing technology advances.
What is ANPR used for?
1. ANPR (www.anpr.org.uk) is already in widespread use throughout the UK. It’s use dates back to 1997, when 100 ANPR cameras codenamed GLUTTON were installed in Northern Ireland.
2. Transport For London (www.tfl.gov.uk) famously implemented a 250 camera strong ANPR system within London’s congestion charging zone. It is estimated that approximately 98% of vehicles moving within the charging zone are caught on camera.
3. There is also a new breed of speed cameras, the most popular of which being called SPECS, that in combination with ANPR are able to match two different pictures taken from separated cameras in order to monitor and report your speed over long distances.
4. A network of over 2000 further cameras is planned throughout mainland UK in a bid to make Britain the first ever country to monitor and record every journey that any vehicle ever makes!
5. Internationally, Melbourne, California, New York, New Jersey, Massachusetts, Oklahoma and Santiago all have systems implemented on various toll roads.
ANPR however, is a fairly recent innovation, it’s applications look set to spread into more and more motoring areas; petrol stations, car parks, fine enforcement and international border control are all areas which either have already or are seriously considering implementing ANPR schemes.
How does it work?
In basic terms, the system is very much like a desktop computer scanner coupled
with OCR (Optical Character Recognition) software, albeit in a very specialised
form. Anyone who has ever scanned a printed document for later editing in a
word processor such as Microsoft Word will have used and may already be familiar
with this technology.
When a computer performs Optical Character Recognition it takes an image (essentially a digital photo) of a series of words. By examining each character (or symbol as a computer would see it) individually, looking at where the lines begin, intersect and end, along with the shape of the lines themselves it is able to ascertain which letter or number each symbol represents. For example, it may distinguish a C from a 0 by finding the missing vertical curve on the right hand side of the symbol. The human brain does all of this in no time, for all but the most advanced computers it is no trivial task.
An ANPR system has a lot more work to do than your office’s flatbed scanner of course! A picture analysed by ANPR software will have the road, the sky, the car itself and possibly other vehicles within frame. As such the ANPR system needs a few extra bits of computer trickery to get at your plate number:
1. Localisation & Isolation – the
piece of software responsible for cutting everything apart from the plate itself
from the picture delivered by the camera.
2. Sizing & Orientation – responsible for making
sure the plate appears flat and horizontal, and is of the correct dimensions
for Optical Character Recognition.
3. Normalisation – adjusts brightness, gamma and contrast
of the image for optimum visibility to the computer.
4. Character Segmentation – now that the system has a
clear image of the plate in isolation it will look for the spaces between symbols
so it can attempt to understand the symbols themselves in isolation.
5. Optical Character Recognition – yes, this is the bit
your scanner at home can also do! Here the system examines the shape of each
symbol and understands which letter or number the symbol represents.
I’ve
Been Spotted, What Happens Next?
Within itself, a computer having recognised your number plate is fairly pointless
in all but the most hardened geek’s eyes. The clever bit actually happens
when this license plate information is transmitted over the air or over the
wire to one or more databases.
Any database which holds your license plate number can be used to gain further information about yourself, a striking example of this is the DVLA (www.dvla.gov.uk) database which holds every imaginable detail about both your car’s history and your own driving history. Information about your MOT, insurance, and every car you have ever legally owned is just one ANPR camera away.
A more chilling thought for crooks of this country emerges when combining ANPR with the Police database. If your plate number is linked to your record then you better find a sneaky way round those cameras (or get some gaffer tape over your plates!). A single camera could spot you and alert the authorities as to your precise whereabouts and direction within seconds. After Sharon Beshenivsky (a British police constable) was shot dead during a robbery in Bradford, nearby CCTV cameras equipped with ANPR successfully identified the getaway car, implicating six suspects, leading ultimately in their arrest.
I Don’t Like the Idea of Being Watched Wherever
I Go!
You’re not alone on this one. ANPR schemes have produced a lot of controversy
since their introduction. Privacy concerns, fears over automated or computerised
policing and speculation over inaccuracies and false positives have been widely
covered throughout the press.
Instead of telling you what we think, we’d like to hear your views on the matter. Email us at readers@creditplus.co.uk - you might get published right here and could win arguably the most important piece of technology to ever hit the roads – a 2nd generation iPod Nano!
Next Week….
When our Tech-Talk! series continues we’ll be covering the subject dearest
to every motorist – Your Car! We’ll be finding out how many microprocessors
are under the bonnet, but more importantly, what the hell do they actually do?
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