Method and system for designing multilevel halftone screens using spot functions
AssigneeInfoPrint Solutions Company LLC
InventorsHong Li, Mikel John Stanich, Gerhard R. Thompson, Chai Wah Wu
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Abstract
A method and system for generating halftone tables, using a spot function, subdivides the pixels within the halftone cell of a halftone matrix into a plurality of sub-pixels, determines the value of the spot function corresponding to the position of each of the sub-pixels within the halftone matrix, repeats the subdividing and determining for all of the sub-pixels in the halftone matrix, ranks the values for the entire halftone matrix, normalizes the ranked values, generates a cumulative histogram based upon the normalized values, and stores the cumulative histogram as a halftone table.
Claims20
A method comprising:
- subdividing at least one pixel within at least one halftone cell of a halftone matrix into a plurality of sub-pixels;
- determining the value of the spot function corresponding to the position of each sub-pixel of the plurality of sub-pixels within the halftone matrix;
- repeating the subdividing and determining the value of the spot function for all pixels within the halftone matrix;
- ranking the values of the spot function for the entire halftone matrix;
- normalizing each ranked value to an integer;
- generating a cumulative histogram of the sub-pixels based upon the normalized values;
- and
- storing the cumulative histogram as a halftone table.
A method comprising:
- tiling an image using a halftone matrix;
- and
- determining an output value for each pixel of said image using a plurality of halftone tables each corresponding to a pixel position within a halftone cell of the halftone matrix, wherein at least one of the plurality of halftone tables is based upon a cumulative histogram that is based upon values of a spot function applied to all sub-pixels of each pixel in the halftone matrix.
A system comprising:
- means for subdividing at least one pixel within at least one halftone cell of a halftone matrix into a plurality of sub-pixels;
- means for determining the value of the spot function corresponding to the position of all of the plurality of sub-pixels within the halftone matrix;
- means for ranking the spot function values;
- means for normalizing each ranked value to an integer;
- means for generating a cumulative histogram of the sub-pixels of the normalized values;
- and
- means for storing the cumulative histogram as a halftone table.
Dependencies are inferred from the claim text.