Patent ID: 8115779

Claim:
A method for translating a three value color space signal, given in a CIE scale, to an n primary color space signal, wherein n is an integer greater than or equal to 4, using a chromaticity diagram which is expressed in a two dimensional space, where the two dimensions represent a first value and a second value of the three value color space, the chromaticity diagram including n points P 1 through P n each corresponding to one of a plurality of primary colors, the method comprising: mapping at least one point P 0 on the chromaticity diagram, the at least one point P 0 representing a color and being within a polygon with the points P 1 through P n , mapping n triangular areas on the chromaticity diagram, each triangular area having as its corner points the at least one point P 0 and two adjacent points chosen from the points P 1 through P n , mapping the three value color space signal on the chromaticity diagram as a point P x , determining, by a controller, in which triangle the point P x is located, the triangle being formed by the at least one point P 0 and two points from the points P 1 through P n , using the three colors forming the triangle to create an additive linear combination, solving the additive linear combination by representing the contribution of the at least one point P 0 to the n primary color space signal and by representing the contributions of the colors of the two other points to the n primary color space signal, selecting the optimal linear combination for the at least one point P 0 , the optimal linear combination including one of a maximum color rendering index (CRI) and a maximum luminous efficiency for a given value of the other based on stored data, the stored data including a plurality of pre-calculated values of CRI and luminous efficiency for the at least one point P 0 , multiplying all contributions to the optimal linear combination for the at least one point P 0 and the contributions of the colors of the two other points to the n primary color space signal by a constant factor to generate a certain brightness representing the third value of the three value color space, displaying the so derived optimal linear combination for P x by representing the multiplied contributions of the colors of the points P 1 through P n .