SEDL / STP / STP1031-EB / STP23354S

A New Laser, Noncontact Method for Measuring Vehicle-to-Pavement Distance

Caussignac, JM
Central Laboratory for Bridges and Roads (LCPC), Paris,

Morel, G
Central Laboratory for Bridges and Roads (LCPC), Paris,

Charrier, J
Central Laboratory for Bridges and Roads (LCPC), Paris,

Pages: 10    Published: Jan 1990

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Abstract

This paper describes a new laser technique for measuring displacement or the distance from a vehicle to the pavement. This noncontact method is based on the analysis of a nonfocused image of a laser spot by a matrix sensor. We show that the proportion of light energy received by the central pixel and the total energy received by matrix sensor depends on the distance to the pavement. The analog signal is digitized and treated by a computer. This technique is rapid and causes no disturbance to the pavement. The operating range, the resolution, and the height accuracy may be adjusted by changing either the geometric relationship of the different components of the apparatus or the focal length of the lens.