Patent ID: 6876764

Claim:
A method of generating a white signal component from a color signal comprising the steps of: (a) calculating the brightness increases of primary color components constituting the color signal on the basis of each color component; (b) extracting an increase in the white signal component from the brightness increases of the primary color components; and (c) setting the increase in the white signal component as the white signal component of the color signal, wherein, in the step (a), where the color signal is comprised of Red, Green, Blue three-color signals, b 1 is a predetermined constant indicative of scale, Brt is the increase in the brightness of an achromatic color according to input data, Ri, Gi, and Bi are vectors of the three primary color components, and M1 = ( Ri · Ri + Gi · Gi + Bi · Bi ) 2 , vR, vG, and vB which are the respective brightness increases in red, green, and blue components of the color signal, are determined as vR=b 1 *Brt*Ri/M 1 , vG=b 1 *Brt*Gi/M 1 , vB=b 1 *Brt*Bi/M 1 , respectively.