Roads, in the country and in the city, are a major public asset, in Australia and in all countries. To efficiently manage these assets road authorities need accurate, up-to-date information on the condition of their road networks. Automatic monitoring of some aspects of road condition, for example roughness and skid resistance, has been carried out for a number of years. However, one of the most important road quality indicators, the extent and type of cracking, has up until now been measured only by visual inspection. The result is that only very sparse sampling has been carried out, at a very high cost per kilometre, and very little information has therefore been available in this important aspect of road condition.
The NSW Roads and Traffic Authority (RTA) is responsible for monitoring and maintaining the condition of roads in NSW. The RTA came to CSIRO for the solution to the problem of gaining a vast improvement in the quantity and the quality of information on cracking in roads and highways. Our solution – the world’s first real-time crack detection and classification system. A specially fitted truck, fitted with powerful lights and a high-speed digital camera, continuously captures images of the road (each 500 millimetres by 750 millimetres) as the vehicle travels at speeds up to 100 kilometres per hour.
The vehicle can survey over 500 km in a day; 20,000 km in NSW and 1,500 km in South Australia were surveyed during the first half of 1998. All cracking greater than 1 mm in width is detected. All processing is carried out in real time on board the vehicle, so the results of a day’s survey are available as soon as the survey is finished. The benefit is better road management based on much more detailed information than was available previously.
|Image Captured||Detected Cracking|
The plot below shows the kind of output produced by the system. The amount of cracking, calculated as the number of image frames containing some cracking, is plotted against distance along the road. Type and width of cracking are not shown in this figure, but this information is produced also.
Graphical display of a cracking survey
The road crack detection system has received the following awards: