Area-Based Macrotexture Measurements: Stereo Vision Approach

A nationwide survey done in 1996 found safety, pavement condition, and traffic flow as the primary concerns that highway users had regarding roadway aspects that needed improvement. The same survey four years later again found users rating improvements in safety (26%) second only to traffic flow (28%), and then pavement condition (21%) as their highest priorities. Several fundamental surface characteristics have been proposed and used to estimate how our roads are performing in more general terms of safety, durability, comfort, and appearance. Textural character is a common indicator and influence for each of these broader categories of performance. This paper introduces a new system that is being developed to measure the texture of a pavement surface using a stereo vision camera. The proposed system uses relatively low cost off-the-shelf components for capturing images of pavements to obtain three dimensional surface maps of pavement. The paper further describes proof-of-concept testing with the stereo vision system in which the prototype is compared against more conventional texture-measuring systems. The results indicate that the stereo-vision-based technology can provide a more accurate (and relevant) methodology for evaluating pavement surface texture than most currently available technologies. The conclusions encourage a future effort by the larger scientific community to develop methods for characterizing texture that apply three-dimensional surface mapping to further understand and describe the tire-pavement interface.