DOME II: A Parallelized BTF Acquisition System

Abstract

Bidirectional Texture Functions (BTFs) provide a realistic depiction of the appearance of many real-world materials as they contain the spatially varying light scattering behavior of the material surface. Since editing of existing BTF data is still in its early stages, materials have to be measured from real-world samples. In contrast to the related Spatially Varying BRDFs (SVBRDFs), the reflectance information encoded in a BTF also includes nonlocal scattering effects and therefore does not obey energy conservation or reciprocity. While this higher degree of freedom also contributes to an increased realism, it inadvertently calls for an extensive measurement of reflectance samples, as many regularization approaches from BRDF measurement do not apply. In this paper, we present an automated, parallelized, robust, fast and transportable setup for the acquisition of BTFs from flat samples as well as 3D objects using camera and light arrays: the DOME II. In contrast to previous camera array approaches, the present setup, which is comprised of high-quality industry grade components, overcomes several issues regarding stability, reliability and precision. It achieves a well balanced state-of-the-art acquisition performance in terms of speed and quality at reasonable costs.