Position detection method for mirror finished object using Depth from Focus

By specularity (clearness of mirror reflection) of mirror-finished object, we can estimate surface roughness of the polished object. There are several methods to evaluate specularity, but they have to contact a probe to objectpsilas surface and they spoil the evaluated products. Therefore, contactless specularity measuring system has been required. To develop the contactless system, we have to measure object position as preliminary steps. However, there are several difficulties to detect object position due to the mirror-reflection. In this paper, we propose a position detection method of mirror-finished object using depth from focus (DFF) procedure by monocular camera and striped pattern projection. From some experimental results, we can obtain the distance with error within several millimeters.