Color printing look-up-table
AssigneeHewlett-Packard Development Company, L.P.
InventorsJan Morovic, Peter Morovic
Life of this patent
Estimating the term…
Abstract
A look-up table for use in a printing system is created. The printing system prints an input image in a print color space. The look-up table is created by accessing a predetermined look-up table representing a mapping of color values of an input color space to ink-vectors of a print color space; applying a p-by-q halftone threshold matrix to each ink-vector of the predetermined look-up table to generate a p-by-q halftone cell for each ink-vector; and creating a further look-up table which maps, at least a sample of, the color values of input color space to the at least one halftone cell.
Claims13
A method of creating a look-up table for use in a printing system, the printing system printing a color input image in a print color space, the method comprising:
- accessing a predetermined look-up table representing a mapping of color values of an input color space to ink-vectors of the print color space, the print color space having a plurality of primary colors;
- applying a halftone threshold matrix to each ink-vector of the predetermined look-up table to generate a halftone cell for each ink-vector, by comparing each ink-vector to threshold values of the threshold matrix to determine a primary color of the halftone cell for each ink-vector;
- and
- creating a further look-up table which maps, at least a sample of, the color values of the input color space to the halftone cells that have been generated for the ink-vectors of the print color space,
- wherein the printing system uses the further look-up table in printing the color input image in the print color space.
A method of processing a color input image into a printable format, the color input image comprising a plurality of pixels, each pixel having a color value in an input color space and the printable image comprising a plurality of printable pixels defined by an ink-vector in a print color space, the method comprising:
- responsive to an entry being present for a color value of at least one pixel of the input image within a lookup table which maps, at least a sample of, the color values of the input color space to halftone cells, retrieving a corresponding at least one halftone cell from the lookup table which matches the color value of the at least one pixel of the input image;
- responsive to the entry being absent for the color value of the at least one pixel of the input pixel within the lookup table, interpolating the at least one halftone cell from other halftone cells of other entries within the lookup table corresponding to color values enclosing the color value of the at least one pixel of the input image;
- and
- replacing the at least one pixel with one of the at least one halftone cell,
- wherein a printing system prints the color input image in the printable format using the at least one halftone cell that has replaced the at least one pixel of the input image.
One or more non-transitory computer readable storage media comprising instructions stored thereon, that when executed, direct a processor to perform a method comprising:
- responsive to an entry being present for a color value of at least one pixel of an input image within a lookup table which maps, at least a sample of, the color values of the input color space to halftone cells, retrieving a corresponding at least one halftone cell from the lookup table which matches the color value of the at least one pixel of the input image;
- responsive to the entry being absent for the color value of the at least one pixel of the input pixel within the lookup table, interpolating the at least one halftone cell from other halftone cells of other entries within the lookup table corresponding to color values enclosing the color value of the at least one pixel of the input image,
- wherein a printing system prints the color input image using the at least one halftone cell that has replaced the at least one pixel of the input image.
Dependencies are inferred from the claim text.