Patent ID: 7991596
Filing Date: 2011-08-02
Classification: G01N

Abstract:
1. A computer-implemented process for generating a bidirectional reflectance distribution function (BRDF) of a gonioapparent material specimen containing effect flake pigments in a solid medium using limited measurement data, comprising the following steps in any appropriate order: (A) acquiring and inputting into a computing device (1) photometric data comprising spectral or colorimetric data of the gonioapparent material being a function of an illumination angle and a reflective scattering angle, wherein said data being obtained by (a) measurements of the gonioapparent material, (b) previously measured data of the gonioapparent material from a data base containing measurements of the gonioapparent material or (c) simulated data for a gonioapparent material and (2) the refractive index of the solid medium of the gonioapparent material; (B) converting any non-linear photometric data from step (A) above to linear photometric data; (C) using the illumination angle and the reflective scattering angle associated with the linear photometric data and the refractive index of the medium to calculate corresponding effect flake angles; (D) fitting the linear photometric data and the effect flake angle data with an equation describing the linear photometric data as a continuous function of effect flake angle via computer implementation; (E) calculating the corresponding effect flake angle from the illumination angle, reflective scattering angle and refractive index of the solid medium for each combination of illumination and reflective scattering angle needed to calculate the BRDF being generated in step (F); and (F) generating the BRDF for each combination of illumination and reflective scattering angle by calculating each value of the BRDF from the corresponding effect flake angle from step (E) above and the equation developed in step (D) above.