Title: Lighting Design for Automated Pavement Surface Distress Evaluation

Author(s): Tahar El-Korchi, Michael A. Gennert, Matthew O. Ward, and Norman Wittels, Worcester Polytechnic Institute, Worcester, MA 01609

Source: Transportation Research Record, 1311, pp144-148, 1991.

Abstract: Automated pavement surface distress evaluation would be useful a component of computerized pavement management systems. This paper presents methods for applying computer simulations of pavement distress appearance to the design of those evaluation systems. By generalizing the results of crack visibility calculations under varying conditions of lighting, we have reached a number of conclusions about automated evaluation systems, including the facts that there will always be some distress that escapes detection but that the detection probability is calculable. We also show that lighting is important in determining which types of distress and what fraction of distress will evade detection and we discuss the differences between controlled lighting and natural lighting, between ambient or omni-directional lighting and directed lighting, and between single versus multiple light sources. We consider how detailed examination of modeling results can be used to optimize the design of lighting, data acquisition hardware, and image processing software. Since the conclusions depend strongly on the assumptions made in the work, a detailed listing of our assumptions is presented along with suggestions for further testing.

Matthew O. Ward (matt@cs.wpi.edu)