METHOD FOR ESTIMATING REFLECTANCE

摘要

Reflectance is measured conveniently even for a color shifted painting color. First reflectance R(a_a) of first reflected light V_a in an incident plane A is measured, and first locus l of the end point of a first vector H_a(|H_a|=|R(a_a)|) divided equally into two and displacing two-dimensionally in the incident plane A is determined. Second reflectance R(a_b) of second reflected light V_b on the outside of the incident plane A is measured, and second locus m of the end point of a second vector H_b(|H_b|=| R(a_b)|) divided equally into two and displacing three-dimensionally on the outside of the incident plane A is determined. Locus n(x, y, z_i) of the end point of a vector H_i divided equally into two on a plane z=z_i parallel with a plane under measurement is approximated from both loci l and m by a mathematical expression representing an ellipse and a modelled approximation model expression is determined. Finally, overall locus n'(x, y, z) of the entire end points of the vector H' of reflected light V' other than the first reflected light V_a and the second reflected light V_b divided equally into two is determined approximately.