Abstract
The 3-D shape of an object is the most important measurement information data for many applications. Among numerous 3-D measurement method developed, a triangulation light-stripe rangefinding has proven reliable and is most commonly employed. The light-stripe rangefinder is usually required to acquire range data in a short time. Thus far, however, it has been difficult to increase the rate of conventional light-stripe rangefinders because most existing models make use of mechanical scanning mechanisms, such as a rotating mirror. Thus, to realize the goal of a very fast rangefinder, it is necessary to consider improvements of the scanning mechanisms themselves. Although rangefinders with a non-mechanical scanning mechanism were developed to avoid mechanical scanning, they have the disadvantages of low spacial resolution. We here propose a new, fast rangefinding scanning mechanism based on a new design, which, in contrast to conventional mechanical and non-mechanical scanning mechanisms, meet the criteria of fast scanning time and high spacial resolution. The proposed scanning mechanism works as follows: (1) First, we set the intensity of three stripes uniformly and project on the object; (2) second, by adjusting the intensity of the three light-stripes, a combined parabolic output with a single peak is generated; and (3) when the intensity of one of the light sources is lowered, the peak position of the combined output moves to the side of lower intensity. We have designed and built a prototype rangefinder able to acquire a three-dimensional position in 20ms per one point, which outperforms conventional rangefinders. We conclude that the proposed method produces a fast and effective rangefinder to be implemented in many applications.
