A Goniometric System for Measuring Surface Spectral Reflection Using Two Robot Arms

Abstract

This paper proposes a gonio-spectral imaging system for measuring light reflection on an object surface using two robot arms, a multi-band lighting system, and a monochrome digital camera. It can change the incident and viewing angles of surface reflection with four degrees of freedom. The eight-band lighting system allows reliable spectral estimation of surface reflectance. The images captured for various incident and viewing angles are precisely warped as if they were all captured from the same viewing direction. This enables the proposed system to deal with objects with surface texture. Experiments on image warping, three-dimensional reflection measurement and spectral reflectance estimation are conducted for colored and textured objects. The results demonstrate the feasibility of the proposed imaging system.