Process for generating bidirectional reflectance distribution functions of gonioapparent materials with limited measurement data

1. A computer-implemented process for producing a predicted visual display of an object coated with a gonioapparent material containing effect flake pigments in a solid medium, said process comprising the steps of:

(i) generating a bidirectional reflectance distribution function (BRDF) of said gonioapparent material using limited measurement data, said BRDF is generated by a BRDF process 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;

(ii) producing R,G,B values based on said BRDF and shapes of the object, or a portion thereof, and

(iii) producing said predicted visual display of said object on a display media based on said R,G,B values.

2. The computer-implemented process of claim 1 further comprising the steps of:

(ia) calculating color difference or spectral reflectance difference data using said BRDF for said object coated with a different material, at a different geometry, or a combination thereof;

(iia) producing a subsequent visual display based on said shapes of the object, said BRDF and said color difference or spectral reflectance difference data of said object.

3. The computer-implemented process of claim 2 , wherein said predicted visual display and said subsequent visual display are displayed on the same or different display media.

4. The computer-implemented process of claim 1 , wherein the BRDF generated is used to calculate the absolute colorimetric or spectral reflectance data for the object at angles not specifically measured in step (A).

5. The computer-implemented process of claim 1 , wherein three combinations of illumination and reflective scattering angle are used in step (A) and subsequent steps.

6. The computer-implemented process of claim 5 , wherein up to ten combinations of illumination and reflective scattering angle are used in step (A) and subsequent steps.

7. The computer-implemented process of claim 5 , wherein the three combinations of illumination and reflective scattering angle result in detection at aspecular angles of 15, 45 and 110 degrees.

8. The computer-implemented process of claim 1 , wherein the BRDF are combined with spatial texture information to render the predicted visual display of said object.

9. The computer-implemented process of claim 1 wherein the predicted visual display of the object is rendered on a video display device.

10. The computer-implemented process of claim 1 , wherein the predicted visual display of the object is rendered on print media.

11. The computer-implemented process of claim 1 , wherein the predicted visual display of the object is rendered on photographic media.

12. The computer-implemented process of claim 1 , wherein the pigments in the gonioapparent material are aluminum flake pigments.

13. The computer-implemented process of claim 1 , wherein the pigments in the gonioapparent material are hue shifting flake pigments.

14. The computer implemented process of claim 1 further comprising an optional step (G) that converts the BRDF to a non-linear basis.