Guilty Until Proved Innocent

We are all too familiar with the steady growth of surveillance technology. Our movements are constantly monitored by both recorded and 'real-time' Closed-circuit Television (CCTV), Automatic Number-Plate Recognition Cameras (ANPR) and 'Speed Cameras'

You may not, however, be aware of the difference between the two number plate-recognition systems. The standard speed camera has been around for many years and is a fairly basic device. An electronoc sensor works out the speed of a passing vehicle and, if excessive, triggers the camera to take a simple flash photograph. We have probably all seen this happen and wondered who the culprit was.

The image is processed and can be produced as evidence in a dispute. Interestingly, of course, the photograph is likely - although not intended - to reveal the images of the vehicle's occupants as well.

ANPR, on the other hand, is based on an entirely different principle. For a start, it uses infra-red light source, rather than a conventional flash, which relies on the reflective properties of the plate itself to enhance the image.

But the essential difference is that it records every registration it sees in a rather crude 'guilty until proved innocent' manner. ANPR only works with multiple cameras. A second device logs each number again and a computer works out the average speed of each vehicle.

Many will be pleased to hear that council 'belt-tightening' has seen the abandonment of speed cameras in some areas - Swindon switched its off last April and Oxford may follow suit after a £600,000 funding shortfall. But ANPR seems certain to remain it as a far more cost effective option.

Back to News Index