Patents by Inventor David A. Keefer

David A. Keefer has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6778294
    Abstract: A color printer receives N-bit values indicating a computer generated color to be printed. Each N-bit value has a most significant bit (MSB). Upon receiving the N-bit color values, the color printer creates an address from combined multiple-bit segments of each of the received N-bit values, each multiple bit segment includes at least a MSB of each N-bit value. The color printer includes a cache memory, each cache address including first and second entries. The first entry being values indicative of a computer generated color and the second entry being values usable by the color printer to reproduce a color indicated by the first entry. A processor determines if there is a match at an address created from a received computer color value between the first entry and the received computer color value. The processor is responsive to a determined match to access the second entry at the address and to employ the second entry to control the color printer.
    Type: Grant
    Filed: October 26, 1998
    Date of Patent: August 17, 2004
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventor: David A. Keefer
  • Patent number: 6690489
    Abstract: A graphics language interpreter includes one or more color converters that accept input color values and that algorithmically convert such input color values to output color values. The color converters are specified by a standard that defines the predefined graphics language. The color converters use color conversion algorithms that are potentially specified by graphics commands during rendering. A lookup component is associated with the color converters. The lookup component indicates output color values corresponding respectively to selected input color values. The lookup component is initialized with output color values that are converted from the selected input color values by the converters. During rendering, the graphics language interpreter uses the lookup component rather than the one or more color converters to convert input color values to output color values.
    Type: Grant
    Filed: December 2, 1999
    Date of Patent: February 10, 2004
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Steve A. Jacob, David A. Keefer, Michael Stokes