Optical Three-dimensional Shape Measurement Method for Objects with Various Surface Reflectances including Specular Objects

Abstract

This paper describes a 3-D shape measurement system for objects with various reflectance properties. Although triangulation-based 3-D shape measurement methods have been widely used for many industrial applications, generally only Lambertian objects can be measured with the methods. In order to apply this type of measurement method to specular objects, it is necessary for the image sensor to detect the incident position and the angle of the light stripe. However, it is difficult to detect the incident angle of the light stripe using conventional image sensors. Thus, we here devised a sensor which has the capability of detecting the incident angle directly, and then proposed a new 3-D shape measurement method using this sensor. The experimental results demonstrate that the system can measure the shapes of hybrid objects with almost the same level of accuracy as it can those of Lambertian objects and specular objects.