Hewlett-packard Company

Timothy M McDonough

Paul H Dillinger

Aneesa R Scandalis

J Erik Blume

A computerized method, containable in a computer memory device, is disclosed for tristimulus color space coordinate data nonlinear storage, retrieval, and interpolation, and, more specifically to memory mapping and data interpolation for 24-bit L*H*C* to 24-bit RGB color mapping (three 8-bit words to each coordinate). Predetermined output tristimulus color space coordinate data points are stored in nodes of a memory construct based upon use of input values of a cylindrical-based tristimulus color space coordinate system, where a non-linear selection of stored data points is provided in the memory construct. The number of linear interpolations of each of the coordinates is determined by the number of available bits in each data word after providing sufficient bits to address the surrounding stored nodes. Each coordinate conversion is expedited by caching frequently accessed nodes in an auxiliary cache memory, by node doubling of preselected nodes, and by fetching only relevant adjacent nodes during interpolation.

Method for interpolation of tristimulus color data

Method for tristimulus color data non-linear storage, retrieval, and

A method and apparatus for enhancing the quality of images printed by dot printers or dot displays are disclosed. Image irregularities caused by quantization are smoothed by using a set of rules to transform an initial pattern into an enhanced pattern for printing. The initial pattern may consist of a matrix of bits representing an image having X dots per inch along an intended direction of printing. An intermediate pattern is formed by replicating columns of bits from the initial pattern. Image enhancement rules are applied to the intermediate pattern to invert one or more bits in the intermediate pattern to create an enhanced pattern. The enhanced pattern is printed at n*X dots per inch along the direction of printing where n.gtoreq.1.

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Escondido, CA, United States of America

Timothy M McDonough