INEXPENSIVE 3-D LASER SCANNER SYSTEM BASED ON A GALVANOMETER SCAN HEAD

摘要

This paper deals with a 3-D scanning system based on relatively inexpensive, off-the-shelf products. Although there exist many techniques for obtaining information about object position, size and form, it is still possible to find specific applications where none of the conventional methods seem to satisfy the requirements. Such applications are encountered in challenging environments where one has to simultaneously gather information quickly, with high accuracy and without interaction with the object of interest. The instruments also need to be kept simple, cost effective and robust. In this paper, we propose and investigate a system that angles a beam from a laser rangefinder along the object of interest, in order to determine the object's geometrical properties. The beam is angled by means of a galvanometer scan head. The scanned pattern is conditioned by the assumed object form and position. The pattern is adjusted during the measurement in an appropriate way so that the scanning time is minimized. The object form assumed is a series of concentric pipes of relatively small and varying diameter (10 - 50 cm). The system is designed to determine the position of the joints and the diameters of the pipe sections. This article specifies the characteristics of the system and discusses the various parameters limiting the system performance. Although the system components were not optimal with respect to the measurement requirements, the system's performance is designated as satisfactory. The system can easily be improved by exchanging the components with more suitable units.