Constrained digital halftoning
AssigneeInternational Business Machines Corporation
InventorsRoy L. Adler, Marco Martens, Joan L. Mitchell, Nenad Rijavec, Robert H. Risch, Charles P. Tresser, Chai W. Wu
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Abstract
A method and apparatus for halftoning digital images renders color data subject to constraints on the number of colorants which can be deposited on a single pixel and constraints on consecutive pixels rendered with the same color. The color data to be rendered is mapped into a second data set in an achievable color gamut space. Then, using a digital halftoning method in the achievable color gamut space, the second data set is rendered, so that the constraints are satisfied.
Claims40
A method to render color data with a restriction that, of a full set of rendering colors which can individually be used in a pixel, any plurality of said colors cannot be used, in the same pixel comprising the steps of:
- mapping the color data to be rendered into a second data set in an achievable color gamut space;
- and
- using a digital halftoning method in the achievable color gamut space to render said second data set, so that said restriction is satisfied.
A method to render color data comprising the steps of:
- mapping each image pixel of the color data through a gamut map into a second data set where said gamut map maps each ray through an origin in a full color gamut space onto a ray through the origin in an achievable color gamut space;
- and
- using a digital halftoning method in the achievable color gamut space to render said second data set.
An apparatus to render color data with a restriction that, of a full set of rendering colors which can individually be used in a pixel, any plurality of said colors cannot be used in the same pixel, said apparatus comprising:
- mapping means for mapping the color data to be rendered into a second data set in an achievable color gamut space;
- and
- rendering means using a digital halftoning method in the achievable color gamut space for rendering said second data set, so that said restriction is satisfied.
An apparatus for rendering color data comprising:
- mapping means for mapping each image pixel of the color data through a gamut map into a second data set where said gamut map maps each ray through an origin in a full color gamut space onto a ray through the origin in an achievable color gamut space;
- and
- rendering means using a digital halftoning method in the achievable color gamut space to render said second data set.
Dependencies are inferred from the claim text.