3-D shape measurement by inverse raytracing approach

A triangulation-based laser rangefinder is able to achieve a favorable balance between measurement accuracy and measurement. time. However, it. is known that conventional triangulation-based rangefinder has difficulty applying to 3-D shape measurement of specular objects with shiny surface. We previously proposed two approaches to overcome the above problem that conventional triangulation-based rangefinder cannot apply to 3-D shape measurement of specular objects. It is true that the previously proposed approaches allowed to measure the 3-D shape of specular objects, but their approaches have leaved the some problems that needs to be solved. In this paper, we propose a novel rangefinding approach which does not cause the above errors for specular objects, compared to the previous approach. The basic concept of the proposed approach is to detect the position and incident angle of a light spot by using a newly-devised sensor and derive an inverse raytracing equation by rigorous geometric optics analysis.