An Image based Measurement System for Anisotropic Reflection

Abstract

This paper introduces an image based method for measuring bidirectional reflectance distribution functions (BRDF). The measurement system uses a CCD camera connected to a workstation to capture images from the material under investigation. The evaluation of the BRDF is performed in an image processing step, gathering BRDF values with a broad range of incident and reflected angles, followed by a fitting process, where these values are approximated by a chosen reflectance model. Absolute BRDF values are obtained by the usage of a diffuse reflectance standard. It is shown that the proposed measurement system produces very reasonable results compared to accurate measurements. Thus, it is an easy and cost efficient way to measure material properties needed for physically based rendering algorithms.