US 5,963,714 A · Multicolor and mixed-mode halftoning

Abstract

A printer driver operates a printer capable of multiple dot-placement geometries or resolutions and multiple inks per color channel. It maps a continuous-tone cyan pixel-component value to continuous-tone light- and dark-cyan values, which it separately halftones to respective binary pixel values that respectively indicate whether an associated pixel will receive light- and dark-cyan ink dots. It similarly generates binary values that respectively indicate whether an associated pixel will receive light- and dark-magenta ink dots. In performing the halftoning, the driver separately performs error diffusion through different interleaved sub-images of the image to be printed so that the error-diffusion process is performed for images whose pixel geometry is that for which the process was designed even though the overall image's pixel geometry is not. The result is a modular, scaleable architecture, in which designs for one ink per channel and/or one dot-placement geometry can be adapted with minimal design effort to multiple inks and dot-placement geometries.

Claims34

Dependent claims

For operating an image-presenting mechanism responsive to the application thereto of electrical command signals to display an image that the command signals represent, a method comprising the steps of:

A) performing a sequence of image-revision steps, in which sequence each image-revision step receives electrical input signals representing an input image consisting of input pixels that the input signals represent as respective input-pixel values, each of which consists of one pixel component value for each of at least one image component of which the input image consists and produces therefrom electrical output signals representing an output image consisting of output pixels that the output signals represent as respective output-pixel values, the input image of the first image-revision step is the source image, the input image of any subsequent image-revision step is the output image of the preceding image-revision step, and in which one said image-revision step is a half-toning step that comprises, for at least one image component:
i) generating from the halftoning step's input image a plurality of mapped sub-images;
ii) generating respective halftoned sub-images by separately halftoning the mapped sub-images;
and
iii) generating the halftoning step's output image by interleaving the halftoned sub-images;
and
B) applying to the image-presenting mechanism electrical command signals that represent the output image produced by the last image-revision step.

4 more elements

For operating an image-presenting mechanism responsive to the application thereto of electrical command signals to display an image that the command signals represent, a apparatus comprising:

A) image-revision circuitry, responsive to electrical source-image signals representing a source image, for performing on the source image a sequence of image-revision steps, in which sequence each image-revision step receives electrical input signals representing an input image consisting of input pixels that the input signals represent as respective input-pixel values, each of which consists of one pixel component value for each of at least one image component of which the input image consists and produces therefrom electrical output signals representing an output image consisting of output pixels that the output signals represent as respective output-pixel values, the input image of the first image-revision step is the source image, the input image of any subsequent image-revision step is the output image of the preceding image-revision step, and in which one said image-revision step is a half-toning step that comprises, for at least one image component:
i) generating from the halftoning step's input image a plurality of mapped sub-images;
ii) generating respective halftoned sub-images by separately halftoning the mapped sub-images;
and
iii) generating the halftoning step's output image by interleaving the halftoned sub-images;
and
B) output circuitry responsive to the image-revision circuitry for applying to the image-presenting mechanism electrical command signals that represent the output image produced by the last image-revision step.

4 more elements

A storage medium containing instructions readable by a computer to configure the computer to function as an apparatus for operating an image-presenting mechanism responsive to the application thereto of electrical command signals to display an image that the command signals represent, which apparatus comprises:

A) image-revision circuitry, responsive to electrical source-image signals representing a source image, for performing on the source image a sequence of image-revision steps, in which sequence each image-revision step receives electrical input signals representing an input image consisting of input pixels that the input signals represent as respective input-pixel values, each of which consists of one pixel component value for each of at least one image component of which the input image consists and produces therefrom electrical output signals representing an output image consisting of output pixels that the output signals represent as respective output-pixel values, the input image of the first image-revision step is the source image, the input image of any subsequent image-revision step is the output image of the preceding image-revision step, and in which one said image-revision step is a half-toning step that comprises, for at least one image component:
i) generating from the halftoning step's input image a plurality of mapped sub-images;
ii) generating respective halftoned sub-images by separately halftoning the mapped sub-images;
and
iii) generating the halftoning step's output image by interleaving the halftoned sub-images;
and
B) output circuitry responsive to the image-revision circuitry for applying to the image-presenting mechanism electrical command signals that represent the output image produced by the last image-revision step.

4 more elements

A) performing a sequence of image-revision steps, in which sequence each image-revision step receives electrical input signals representing an input image consisting of input pixels that the input signals represent as respective input-pixel values, each of which consists of one pixel component value for each of a plurality of image components of which the input image consists and produces therefrom electrical output signals representing an output image consisting of output pixels that the output signals represent as respective-pixel component values, the input image of the first image-revision step is the source image, the input image of any subsequent image-revision step is the output image of the preceding image-revision step, and in which one said image-revision step is a half-toning step that comprises:
i) generating separate light- and dark-color continuous-tone image components from an image component of the halftoning step's input image;
ii) generating light- and dark-color halftone image components by separately halftoning the light- and dark-color continuous-tone image components;
and
iii) including the light- and dark-color halftone image components in the halftoning step's output image;
and
B) applying to the image-presenting mechanism electrical command signals that cause it to apply to an image medium separate light and dark imaging agents of the same color in accordance with the light- and dark-color halftone image components, respectively.

4 more elements

For operating an image-presenting mechanism responsive to the application thereto of electrical command signals to display an image that the command signals represent, an apparatus comprising:

A) image-revision circuitry, responsive to electrical source-image signals representing a source image, for performing on the source image a sequence of image-revision steps, in which sequence each image-revision step receives electrical input signals representing an input image consisting of input pixels that the input signals represent as respective input-pixel values, each of which consists of one pixel component value for each of a plurality of image components of which the input image consists and produces therefrom electrical output signals representing an output image consisting of output pixels that the output signals represent as respective-pixel component values, the input image of the first image-revision step is the source image, the input image of any subsequent image-revision step is the output image of the preceding image-revision step, and in which one said image-revision step is a half-toning step that comprises:
i) generating separate light- and dark-color continuous-tone image components from an image component of the halftoning step's input image;
ii) generating light- and dark-color halftone image components by separately halftoning the light- and dark-color continuous-tone image components;
and
iii) including the light- and dark-color halftone image components in the halftoning step's output image;
and
B) output circuitry responsive to the image-revision circuitry for applying to the image-presenting mechanism electrical command signals that cause it to apply to an image medium separate light and dark imaging agents of the same color in accordance with the light- and dark-color halftone image components, respectively.

4 more elements

A) image-revision circuitry, responsive to electrical source-image signals representing a source image, for performing on the source image a sequence of image-revision steps, in which sequence each image-revision step receives electrical input signals representing an input image consisting of input pixels that the input signals represent as respective input-pixel values, each of which consists of one pixel component value for each of a plurality of image components of which the input image consists and produces therefrom electrical output signals representing an output image consisting of output pixels that the output signals represent as respective-pixel component values, the input image of the first image-revision step is the source image, the input image of any subsequent image-revision step is the output image of the preceding image-revision step, and in which one said image-revision step is a half-toning step that comprises:
i) generating separate light- and dark-color continuous-tone image components from an image component of the halftoning step's input image;
ii) generating light- and dark-color halftone image components by separately halftoning the light- and dark-color continuous-tone image components;
and
iii) including the light- and dark-color halftone image components in the halftoning step's output image;
and
B) output circuitry responsive to the image-revision circuitry for applying to the image-presenting mechanism electrical command signals that cause it to apply to an image medium separate light and dark imaging agents of the same color in accordance with the light- and dark-color halftone image components, respectively.

4 more elements

Dependencies are inferred from the claim text.

Multicolor and mixed-mode halftoning

Life of this patent

Multicolor and mixed-mode halftoning

Life of this patent

Abstract

Claims34