Measuring reflective properties of surfaces using OPTE-F3K

Modern computer lighting design programs are using purely diffuse reflecting surfaces during calculations for simplification reasons. For more accurate calculations it is necessary to use real reflective properties of surfaces that can be measured by a reflectophotometer. The reflectophotometer OPTE-F3K of the Department of Electrical Power Engineering, FEE CTU in Prague, allows measuring reflective properties of surface samples 2 by 2 cm. ReflectoSoft, an application designed especially for this reflectophotometer, enables measurements of BRDF in the Klems system of patches. The measured values can then be stored into an XML file containing the BRDF matrix of 145 × 145 elements. The results can be viewed using the software BSDFViewer. The goal of this paper is to present the current state of the renovation of OPTE-F3K, which enables ray tracing algorithms to use measured reflective properties of real materials.