Optimization of the photometric stereo method for measuring pavement texture properties

The texture of the pavement surface, in addition to the traffic safety, plays a major role in the driving comfort and performance of the vehicle. A dozen of methods have been introduced for determining the pavement texture and each of them has advantages and disadvantages. The usage of the image processing as one of the newest methods is expanding because of its significant advantages. In this study, by constructing a device for taking a picture with different light angles from the pavement surface and using a four lights photometric stereo method, the pavements with different texture have been investigated. Finally, for pavements with different texture type, the optimal angles of different light have been introduced for use in photometric stereo technique. The results show that the adverse relationship between the optimum zenith angle and the depth of texture of the pavement surface, such that by increasing the mean texture depth, using the less zenith angle will give better results.