On-line Simultaneous Measurement of Three Dimensional Shape and Glossiness with Specular Objects

点击翻译按钮获取中文摘要

Many practical tasks in industry often require the determination of the three-dimensional (3-D) shapes of objects with specular surfaces, such as polished metal parts, soldered joints or welded areas. Although several methods exist for the determination of such information, these methods have been only partially succeeded in determining of shape information due to the following two limitations :(1) These methods have generally assumed the objects' reflectance properties to be exclusively Lambertian or specular.(2) The accuracy of shape measurement has strongly deepened on the accuracy of image intensity measurement.In 1998, we have proposed a new laser rangefinder for measuring the 3-D shapes of specular objects. The basic concept of the proposed rangefinder is to limit the incident angle of a light-strip upon the image sensor to a constant angle using shield masks, resulting in the ability to apply a triangulation system to the measurement of specular objects. And, we derived the equations to determine an objects' 3-D positions by triangulation and applied them to the rangefinder.In 1999, we designed and built a prototype rangefinder, which fulfils the requirements of our original idea. Experiments using the rangefinder successfully achieve accurate measurements using light-stripe projection. The rangefinder is promising for many common industrial tasks including measurement of the shapes of polished metal objects and the inspection of solder joint surface. Important factors limiting the rangefinder's practical applications are its field of view, depth of field and speed when applied to specular objects.