Road Visibility Research Articles

Two-dimensional road shape optimisation using genetic algorithms

This research describes the development of a generic road shape modelling algorithm for simulation of traffic scenes. The proposed algorithm simulates horizontal road alignment, according to the road geometry design standards, in the form of alternating straight section and curve segment arrangement. We utilise genetic algorithms to optimise the road shape with regard to real road design considerations such as road curvature and visibility distance. The input to the system is a set of critical points representing points with extreme road curvature. The output is the two-dimensional coordinates of the road centreline (alignment), optimised for driver's safety and comfort. The algorithm produces successful results for various road types and shapes, and exhibits good tolerance to noise.

Vehicle extraction using spatial differentiation and subtraction

In this paper we propose a method, which is executable on today's commercially available image processors, for extracting vehicles. The method is summarized as follows: (1) First, the method generates an initial background image by extracting a background region using logical OR operations among sequentially inputted and subtracted images. (2) Second, on the basis of the change ratio of the brightness of visible road surface, the method dynamically updates the background image by estimating brightness of road surface regions hidden by vehicles. (3) Finally, the method extracts the vehicles using images subtracted by the background image and spatially differentiated images. In preliminary experiments we obtained a good background image by updating it with moving shadows, even under bad conditions at dusk. Furthermore, we had good accuracy in traffic flow measurements, with more than a 95% recognition rate of vehicles and only 3% overdetection. We confirmed the effectiveness of the method by the above evaluation experiments. © 1998 Scripta Technica, Syst Comp Jpn, 29(7): 21–32, 1998

Factors Essential for the Success of a Master Gardener Demonstration Garden

Penobscot Co. (ME) Master Gardeners initiated a highly successful demonstration garden in 1994, on the university's sustainable agriculture farm. Five factors for the garden's success are suggested for consideration by groups planning similar projects: 1) The garden has a permanent site with excellent road visibility, on a public farm that supports public service; 2) The farm manager tills the plot and manages cover crops; 3) 10 to 12 Master Gardeners and two extension educators commit significant ongoing labor to the project; 4) Local businesses supply plants and other materials; 5) A vital statewide Master Gardener Program assures an ongoing supply of volunteers, ideas and enthusiasm.

Instrumentation for mapping light intensity contours

Automobile headlamp illumination is of concern because uniformity and shape of the beam pattern are quite important for optimum road visibility and safety for oncoming drivers. The Society of Automotive Engineers' specification on headlamp illumination [1] designates the maximum and minimum intensities at several spots within the beam. Many states require inspection of vehicle-mounted headlamps for illumination and aiming, and this test is commonly performed using a device which clamps on the headlamp lens. This clamp-on device is limited to checking the maximum intensity at beam center, rather than checking the overall beam pattern to the SAE-J579a specifications. In addition, mechanical limitations of this device have often resulted in the mis-aiming of vehicle headlamps. Present instrumentation available for measuring light intensity per SAE-J579a is primarily of the photo-cell type device, and the point-to-point measurement of light intensities is quite tedious and time consuming. A technique is described in this paper which incorporates electronic signal processing into a closed-circuit television system for displaying contours of constant illumination intensity. The technique is capable of rapidly performing vehicle-mounted headlamp testing per SAE-J579a and could be adapted for use at state inspection stations.