Bidirectional reflectance analysis and visualization operations (BRAVO): a 3D visualization and processing tool for bidirectional reflectance distribution function (BRDF) data
Robert A. Shepherd · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1994
A software tool called BRAVO (bidirectional reflectance analysis and visualization operations) has been developed for silicon graphics workstations to graphically display sampled BRDF data and to quickly generate highly detailed and complete BRDF data tables that are required by ray-tracing signature prediction codes such as LFWC's MCFAC. For a given incidence angle, measured BRDF values are displayed as colored dots located on a hemisphere at the angles they were measured. The color of each data point corresponds to its BRDF value. The hemisphere can be rotated in real time to be viewed from any angle, thus giving an undistorted 3-dimensional presentation of the data. In addition to displaying the raw BRDF data, a bicubic spline interpolation can be performed to generate a full hemispherical BRDF map with a selected 1 or 5 degree resolution. Interpolated data are represented by a hemisphere that is completely colored using Gouraud shading. Once interpolated, the data set is sufficiently resolved for BRAVO to calculate the directional reflectance (DR) value by numerical integration. If desired, BRAVO can then be used to normalize the BRDF to a known DR.