Managing traffic control automation

License plate recognition and rail inspection are hot topics in the infrastructure community. So how can automatic camera inspection help transport infrastructure operators improve safety and efficiency?

“By managing traffic control automation in the right manner, we will be able to integrate all required information into one efficient system”
-Paul van der Velde

Traffic control is one of the most pressing issues in the infrastructure industry, and current developments in rail inspection outline the complexity of this subject. The rails of the Dutch Railways are still inspected manually, with inspectors checking the railway yards for wear and other defects inch-by-inch. This is particularly done at exchange points. Nowadays this method might sound outdated, but it is still the most reliable, and there’s just one reason for this: the alternative, which is automatic camera inspection, is extremely complex. Only the most experienced and technically grounded lighting professionals are able to develop a system that equals the quality of manual inspection. These professionals are extremely hard to find.

However, this does not mean that they do not exist at all. Paul van der Velde and Math Koch of the Netherlands-based Vision Light Tech are currently working on the most complex part of the camera inspection system: the illumination. “We need a constant amount of light for automatic inspection,” explains Koch. “Most preferably it should resemble the natural light on a sunny day. Illumination does not revolve around light on its own. It also encompasses the use of filters and lenses. Only an optimised combination of these three elements enables the high and constant light quality that is necessary to reach similar or even better results.”

The holy trinity: light, lens and filter
The whole issue is to achieve as high a contrast as possible. “The higher the contrast, the clearer the image is,” continues van der Velde. “This is best illustrated by means of another example – license plate recognition.” There are several organisations with diverse reasons for checking out vehicles. The government does not just check speed, but is also interested in country of origin, truck loads and other information that can be traced by codes on vehicles. “Naturally, these codes and license plates come in all sorts of colours and shapes,” he explains. “Recognition is also hampered by influences such as speed, weather conditions and pollution; moreover, it is not in the driver’s best interest to continually be distracted by sudden light flashes.”

Van der Velde believes that with so many factors that need to be considered, the control devices require a certain degree of ‘invisibility’. “The questions remaining are which combination of light, lens and filter offers the highest contrast for every situation imaginable, and which wavelength is required to enable recognition of every possible license plate?” he says. “Raising these issues is crucial when determining the maximum amount of contrast necessary for creating an optimized inspection system. Subsequent tests can be done to determine whether the correct solution is chosen – although by now we already know the answers in advance! Over the course of the last few years we have fitted many automated control systems with illumination, and are now able to offer our customers the possibility to test our systems before purchasing them.”

Making vehicle recognition relatively simple
A current hot topic in the light industry seems to be finding the right people. “At this moment, much is being invested in European infrastructure, and vehicle recognition is an important issue,” concludes van der Velde. “By managing this project correctly, we will be able to integrate all the required information into one efficient system. Concentrating on the optical elements of the system is crucial.”