Portable setup for effective measurement of the surface light-scattering properties

Abstract

The objects with complex scattering properties with rough surfaces and heterogeneous media are widely used in various light-guiding devices, car dashboards, luminaires, and other illuminating systems as elements of scenes aimed to generate images with photorealistic quality. In most cases, such properties are described with Bi-directional Scattering Distribution Functions (BSDF). Typically, such functions are obtained with different measuring devices, like goniophotometers. However, the measurements of such functions are a complex task because of their multidimensional character and complex angular shape. At the present a lot of devices aimed at BSDF measurements have been developed, however all of them have a set of drawbacks, for example, it may be very complex construction, which makes such devices expensive in the manufacturing, or noticeable overall dimensions, what results in their inconvenient not portable usage, low speed of measurements. On the other side, other simpler category of BSDF measuring devices does not have sufficient accuracy, a restricted number of measurement directions, and a very restricted set of functions not allowing to measure such complex optical effects as polarization and fluorescence. In the given paper an original construction of the BSDF measuring device is considered, which does not have the mentioned drawbacks and combines most of the advantages of existing solutions. The proposed measurement setup has small overall dimensions, a simple and cheap construction keeping high accuracy and measurement speed, and a wide set of supported effects like polarization and fluorescence. The advantages of the developed measurement setup are proved with the accurate computer model based on BSDF obtained with the measurements of real samples.