Patents Represented by Attorney, Agent or Law Firm George N. Stevens
  • Patent number: 6172692
    Abstract: A device and method of printing a color image using a lookup table that indicates the amount of at least two concentrations of a given ink color to use. Initially, several color wedges made from uniformly distributed digital counts for each color from lightest to darkest are printed. The color lightness value for each wedge is then measured as an L* value of the CIELAB system along with a granularity value. An interpolation process is then performed to determine the color lightness values and granularity values for color values between wedges. A diluted ink minimum color lightness point is identified by determining the darkest color that can be generated using only diluted ink. Ink patterns are then selected using only diluted ink for color lightness values lighter than the diluted ink minimum lightness point in the lookup table. A zero diluted ink starting point is then identified by determining that granularity improvement cannot be achieved significantly when adding more diluted ink to a pixel matrix.
    Type: Grant
    Filed: February 11, 1999
    Date of Patent: January 9, 2001
    Assignee: Lexmark International, Inc.
    Inventors: Xuan-Chao Huang, Brant Dennis Nystrom