Patent ID: 7679782

Claim:
A system for gray extraction in a multicolor document output device comprising: means adapted for receiving substantially non-linear, device independent color data having at least three color components, corresponding to an associated electronic document; means adapted for calculating a first difference value between a first color component of the at least three color components and a second color component of the at least three color components; means adapted for calculating a second difference value between the first color component of the at least three color components and a third color component of the at least three color components; means adapted for receiving first tolerance data values representative of a selected range of the device independent color data corresponding to gray coloration associated with the calculated first difference value; means adapted for receiving second tolerance data values representative of a selected range of the device independent color data corresponding to gray coloration associated with the calculated second difference value; and gray conversion means adapted for generating single color gray data from the color data in accordance with the first and second difference values and the first and second tolerance data values; wherein the first color component is represented by a tristimulus value Y, the second color component is represented by a tristimulus value X, the third color component is represented by a tristimulus value Z, and wherein the gray conversion means includes means adapted for generating the single color gray data in a selected range defined by: |( X/X W −Y/Y W )< t X ( Y ); and |( Z/Z W −Y/Y W )< t Z ( Y ); wherein t X (Y) and t Z (Y) define the first and second tolerance data values corresponding to a value of the first color component.