摘要:
A de-warp map is generated by applying principal component analysis (PCA) to vectors describing aspects of identified features of an object in an image. PCA provides vectors and coefficients describing curvature or image warping at selected points in the image. Estimates of the warping of the image generally are generated by interpolation and/or extrapolation from the vectors and coefficients provided by PCA. In some applications only two features need be identified. For example, the complicated curvature of the facing pages of an open book can be characterized by two vectors describing positions of top and bottom edges of the book. In such applications PCA can reduce to vector subtraction to determine a basis vector, vector addition and scaling to determine an average vector and simple assignment of known coefficient values. The de-warping map can be used to generate a de-warped version of the image.
摘要:
Color management constraints on the use of selected hypocolorant(s) and a black colorant in the rendering of a given pixel reduce ink or toner usage and/or reduce pressure on an ink limit. Additionally, the enforcement of this mutual exclusivity between the black and the selected hypocolorant(s) allows screen frequencies and angles to be shared between halftone screens used for the black colorant and a selected hypocolorant. This reduces the likelihood of objectionable moiré associated with the use of hypocolorant colorants in addition to the conventional CMY(K) colorants. In some embodiments, color management constraints prevent the use of black colorant for pixels beyond a threshold lightness or luminance. This constraint allows the use of the selected hypocolorants in the region of color space beyond the threshold. The threshold can be a function of hue and/or chroma. In some embodiments the threshold is a constant.
摘要:
The present disclosure provides processes for producing images of excellent color fidelity when incorporating a cyan toner with a lower colorant loading in addition to a first cyan toner. In embodiments, the cyan pigmented particles may be cyan emulsion aggregation toners. In accordance with the present disclosure, a pair of cyan toners are matched in color, wherein the color of a first cyan toner printed at a predetermined halftone area coverage on a substrate substantially matches the color of the solid (100%) printed patch of the second cyan toner, which is lighter than the first cyan toner, thus avoiding a visible hue shift on the print that would otherwise be objectionable. In embodiments, the light cyan toner is color matched by adding a hue-adjusting colorant or combination of colorants which absorb wavelengths of light between 500 and 600 nanometers, and optionally adding a shade-adjusting colorant or combination of colorants which absorb wavelengths of light between 400 and 500 nanometers.
摘要:
A method for estimating the color of a coated print includes: measuring the color of an uncoated print with a color measuring device; and estimating the color of the print when coated by a coating process based on the uncoated color measurement using a function that correlates uncoated color measurements and coated color measurements; and adjusting at least one parameter of the printing process based on the coated color estimation. The correlating function may be derived by measuring the color of a plurality of uncoated color patches; measuring the color of the plurality of patches after the patches have been coated by the coating process; and correlating the color of the coated patches with the uncoated patches based on the coated and uncoated color patch measurements.
摘要:
Colorant recipes for spot colors, or colors associated with vector graphic objects, are transformed to compensate for spatial variation in a rendering device. Inverted Jacobians of color production performance can be used to transform color deviations into colorant recipe changes. The colorant recipe changes are applied to original colorant recipes to provide the transformed colorant recipes. Jacobians can be determined by exercising a system model according to perturbations of the colorant recipes. Alternatively, test patches or strips based on perturbed original colorant recipes can be rendered and measured and the Jacobians can be based on such measurements. Alternatively, spatially dependent tone reproduction curves can be used to transform the colorant recipes associated with the vector graphic objects. Image processing systems can include a spatial variation information determiner, a spatial compensation information determiner and a colorant recipe transformer.
摘要:
A de-warp map is generated by applying principal component analysis (PCA) to vectors describing aspects of identified features of an object in an image. PCA provides vectors and coefficients describing curvature or image warping at selected points in the image. Estimates of the warping of the image generally are generated by interpolation and/or extrapolation from the vectors and coefficients provided by PCA. In some applications only two features need be identified. For example, the complicated curvature of the facing pages of an open book can be characterized by two vectors describing positions of top and bottom edges of the book. In such applications PCA can reduce to vector subtraction to determine a basis vector, vector addition and scaling to determine an average vector and simple assignment of known coefficient values. The de-warping map can be used to generate a de-warped version of the image.
摘要:
Color management constraints on the use of selected hypocolorant(s) and a black colorant in the rendering of a given pixel reduce ink or toner usage and/or reduce pressure on an ink limit. Additionally, the enforcement of this mutual exclusivity between the black and the selected hypocolorant(s) allows screen frequencies and angles to be shared between halftone screens used for the black colorant and a selected hypocolorant. This reduces the likelihood of objectionable moiré associated with the use of hypocolorant colorants in addition to the conventional CMY(K) colorants. In some embodiments, color management constraints prevent the use of black colorant for pixels beyond a threshold lightness or luminance. This constraint allows the use of the selected hypocolorants in the region of color space beyond the threshold. The threshold can be a function of hue and/or chroma. In some embodiments the threshold is a constant.
摘要:
Spatially dependent colorant interaction effects are identified and isolated from other aspects of spatially dependent colorant appearance nonuniformities. A decorrelating function for compensating for the identified spatially dependent colorant interaction effects is determined. Spatially dependent single colorant compensating functions for compensating for the other aspects of the spatially dependent colorant appearance nonuniformities may also be determined. Image data is processed through the decorrelating function, thereby generating colorant values that are compensated for spatially dependent colorant interaction effects. Optionally, image data is also processed through the spatially dependent single colorant compensating functions, thereby generating colorant values that are compensated for both aspects of colorant appearance nonuniformities. The two kinds of compensating functions may be determined, calibrated and/or stored at different spatial and temporal frequencies or resolutions. One or both of the compensating functions may be employed to maintain consistency across a plurality of rendering devices (e.g., marking engines).
摘要:
A yellow toner including:a resin, anda colorant comprising a mixture of a yellow pigment and a yellow dye, wherein the combined weight of the colorant is from about 1 to about 50 weight percent of the total weight of the toner, and wherein the chroma of developed toner is from about 90 to about 130 CIELAB units.
摘要:
In a "hi-fi" color printing system, wherein colorants of hi-fi colors beyond the regular CMYK primary colorants are available, a main gamut obtainable with the CMYK colorants only is mutually exclusive with at least one extended gamut in which a hi-fi colorant is used and a complementary one of the CMY colorants is excluded. Because the main and extended gamuts are mutually exclusive, no more than four colorants are used in any part of the image, and no more than four halftone screens need be used to obtain any desired color.