Method and system for designing multilevel halftone screens using spot functions

1. 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.

2. The method of claim 1 , wherein said ranking the spot function values of sub-pixels further comprises assigning an order number to each sub-pixel within the halftone matrix.

3. The method of claim 1 , further comprising quantizing output values from said halftone table.

4. The method of claim 3 , wherein said quantizing is based upon a number of available output levels.

5. 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.

6. The method of claim 5 , further comprising quantizing output values from said halftone table.

7. The method of claim 6 , wherein said cumulative histogram is based upon normalized spot function values for said sub-pixels.

8. The method of claim 7 , wherein said normalized spot function values are based upon ranked spot function values for the sub-pixels for the entire halftone matrix.

9. 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.

10. The system of claim 9 , further comprising means for quantizing an output from the halftone table.

11. The system of claim 10 , wherein said quantizing is based upon a number of available output levels.

12. The system of claim 9 , wherein said means for ranking comprising means for assigning an order number to each sub-pixel within the halftone matrix.

13. A method for deploying computing infrastructure for performing the method of claim 1 , comprising integrating computer-readable code into a computing system, the computer-readable code comprising:

instructions for subdividing at least one pixel within at least one halftone cell of a halftone matrix into a plurality of sub-pixels;

instructions for 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;

instructions for repeating the subdividing and determining the value of the spot function for all pixels within the halftone matrix;

instructions for ranking the values of the spot function for the entire halftone matrix;

instructions for normalizing each ranked value to an integer between 0-255;

instructions for generating a cumulative histogram based upon the normalized values; and

instructions for storing the cumulative histogram as a halftone table.

14. The method of claim 13 , further comprising instructions for quantizing an output from said halftone table.

15. The method of claim 14 , wherein said quantizing is based upon a number of available output levels.

16. The method of claim 13 , wherein said instructions for ranking comprise instructions for assigning an order number to each sub-pixel within the halftone matrix.

17. A system for generating a halftone table using a spot function in accordance with claim 1 , the system comprising:

a sub-divider that subdivides at least one pixel within at least one halftone cell of a halftone matrix into a plurality of sub-pixels;

a processor that determines the value of the spot function corresponding to the position of each the plurality of sub-pixels within the halftone cell, wherein said sub-divider and said processor sub-divide and process all pixels within the halftone matrix;

a ranking device that ranks the values of the spot functions for the entire halftone matrix;

a normalizing device that normalizes the ranked values;

a generator that generates a cumulative histogram based upon the normalized values; and

storage for storing the cumulative histogram as a halftone table.

18. The system of claim 17 , further comprising a quantizer that quantizes an output from the halftone table.

19. The system of claim 18 , wherein said quantizer quantizes said output based upon a number of available output levels.

20. The system of claim 13 , wherein said ranking device further comprising an order number assigning device that assigns an order number to each sub-pixel within the entire halftone matrix.