Image rendering system and method using sum and difference error diffusion with arbitrary and redundant colors
AssigneeXerox Corporation
InventorSteven J. Harrington
Life of this patent
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Abstract
An image rendering system and method use a sum-and-difference error diffusion technique that may be utilized in conjunction with image rendering using more than three colorants, e.g., inks. The colorants may be arbitrary and/or redundant. The sum-and-difference error diffusion technique involves two sets of steps. First, steps for performing specification of a colorant amount are separated from steps for determining colorant placement. Colorant placement is then performed by first summing the total number of colorant requests, including any associated error adjustments, and determining how many units of colorant will be rendered. Second, the adjusted colorant requests are sorted to fulfill the image rendering.
Claims22
An image rendering method using a sum-and-difference error diffusion technique, the method comprising:
- determining ideal colorant amounts at a first location;
- determining a total amount of colorant to be rendered at said first location;
- determining which colorants of a plurality of available colorants to include in the amount of colorant to be placed at the first location simultaneously with the step of determining the amount of colorant to be rendered at the first location,
- wherein the plurality of available colorants includes at least four colorants, not including black;
- determining a total number of colorant requests for the first location;
- adjusting an amount of colorant for each colorant by an error adjustment resulting from rendering colorants at locations other than the first location to provide an adjusted amount of colorant for each colorant at the first location;
- summing an amount of colorant for the total number of colorant requests to produce a total amount of colorant to be rendered at the first location;
- and
- sorting and selecting the colorant requests based on the adjusted amount of colorant for each colorant to fulfill the color image rendering at the first location;
- wherein the step of sorting and selecting is performed by sorting the colorant requests so that colorant requests requesting a larger adjusted amount of colorant are selected before colorant requests requesting a smaller adjusted amount of colorant and results of that sort are used to index a look up table of colorant combinations to be rendered.
An image rendering system using a sum-and-difference error diffusion technique, the system comprising:
- an ideal colorant determination circuit;
- an error adjustment circuit coupled to the ideal colorant determination circuit;
- a specific colorant amount sorting circuit and a total colorant amount determiner, both coupled to the error adjustment circuit;
- a colorant selector coupled to both the specific colorant amount sorting circuit and total colorant amount determiner;
- an error determination circuit coupled to the colorant selector and the error adjustment circuit;
- and
- an image data sink coupled to the colorant selector,
- wherein a plurality of renderable colorants includes at least three colorants, not including black;
- wherein the specific colorant amount sorting circuit sorts the adjusted colorant amounts to identify the colorants with the largest adjusted colorant amounts;
- and sorts the colorant so that colorant requests requesting a larger adjusted amount of colorant are selected before colorant requests requesting a smaller adjusted amount of colorant and results of that sort are used to index a look up table of colorant combinations to be rendered.
Dependencies are inferred from the claim text.