Abstract

Noncontacting surface sensor based on the principle of laser triangulation has been developed for measuring the displacement of objects that have diffuse surfaces. However, (here are two major drawbacks when such a method is used for diffuse surfaces that have low reflectivity, such as a dragonfly wing. The first drawback is that the measured displacement range is limited by the poor linearity that is due to using a short focal-length lens to collect sufficient light. This problem can be understood by looking at the dashed line in Fig. 1. The second drawback is that, due to light-transfer noise inherent in every position sensor cell, reflectivity variations in the diffuse surface produce measurement errors.

© 1996 IEEE