Measurement of three-dimensional profiles with multi structure linear lighting

In reverse engineering, it is very challenging to acquire the 3D profile information of an object rapidly with high accuracy. This becomes even harder to measure the profile of a large object, such as an automobile body press part as it has a wide scope and is not easy to realize. A new non-contact measuring method using multi structure linear lighting (or multi light-knife) based on laser scanning measurement technology is presented in this paper. The principle of the multi light-knife is first presented. To improve the accuracy of the measuring device developed in this work, a virtual net mapping and the least square theory is applied to calibrate the measuring device of the multi light-knife in the whole measuring field. When the device is used to measure automobile body press parts. a route planning method is used to ease the contradiction between measuring accuracy and the range of measurement. System calibration is achieved by compensating the platform error. Experiments on a rear view mirror case show that the multi light-knife is a very effective device and can become a very promising way to acquire the 3D profile information of large objects. (C) 2003 Elsevier Ltd. All rights reserved.