摘要:
A method for adjusting a color in a color space comprises adjusting the color along a gradient path to a point in or on a color gamut. The gradient path is determined from a potential field derived from the color gamut consisting of gamut points in the color space. The potential field can be derived from one or more points in the color gamut and different functions may be used to determine the potentials due to different points in the gamut. The potential at a point in the color space due to the gamut point can be a function, including an inverse power, of distance of the point in the color space from the gamut point. The gradient path can be determined from the gradient of the potential field by quadric error-based surface simplification of a surface mesh representing a surface of the gamut.
摘要:
An improved relief printing plate and method for producing said plate is disclosed. Substantially all sizes of relief features resolve a fixed pattern which improves print quality. The pattern is applied to image areas in halftone data used to produce an image mask that is subsequently used to convert a plate precursor into a relief plate. The accuracy, ink density and tonal response of printed images corresponding to relief features that include the pattern are comparable or better than relief features produced without the pattern.
摘要:
A color imaging technique includes setting a target value in a device-independent first color space and mapping the target value to a substantially complete point set in a second color space. The point set may include a plurality of points, each of which define substantially the same colorimetric value via a unique combination of colorants. After mapping the target value to a substantially complete point set, a point may be chosen. Moreover, after choosing a point in the point set, device-dependent colorant values defined by the point may be determined. In this manner, the invention may provide control over the colorants that are used to image a particular color.
摘要:
A method for adjusting a color in a color space comprises adjusting the color along a gradient path to a point in or on a color gamut. The gradient path is determined from a potential field derived from the color gamut consisting of gamut points in the color space. The potential field can be derived from one or more points in the color gamut and different functions may be used to determine the potentials due to different points in the gamut. The potential at a point in the color space due to the gamut point can be a function, including an inverse power, of distance of the point in the color space from the gamut point. The gradient path can be determined from the gradient of the potential field by quadric error-based surface simplification of a surface mesh representing a surface of the gamut.
摘要:
Modeling spectral characteristics of an image acquisition device. In one implementation, a computer system predicts the spectral reflectance or transmittance of a sample scanned by an image acquisition device, such as a graphic art scanner, by modeling the device. The sample is scanned by a scanner. The computer system searches for media coordinates in a colorant space corresponding to the sample. The media coordinates correspond to an estimated spectrum in a basis spectra model. The basis spectra model is derived by analyzing training color patches of the sample distributed throughout the gamut of the colorant set on the sample media. The estimated spectrum generates estimated digital values through a forward model of the scanner. The estimated digital values are compared to target digital values generated by the scanner to calculate an error value. The computer system repeats this process until a desired stopping criterion or criteria are met. The estimated spectrum corresponding to the final estimated digital values represents the reflectance spectrum of the sample as scanned by the scanner.
摘要:
Modeling spectral characteristics of an image acquisition device. In one implementation, a computer system predicts the spectral reflectance or transmittance of a sample scanned by an image acquisition device, such as a graphics arts scanner, by modeling the device. The sample is scanned by a scanner. The computer system searches for media coordinates in a colorant space corresponding to the sample. The media coordinates correspond to an estimated spectrum in a media model. The estimated spectrum generates estimated digital values through a forward model of the scanner. The estimated digital values are compared to target digital values generated by the scanner to calculate an error value. The computer system repeats this process until a desired stopping criterion or criteria are met. The estimated spectrum corresponding to the final estimated digital values represents the reflectance spectrum of the sample as scanned by the scanner.
摘要:
A system and method for representing a multi-color, halftone image on a multi-color, continuous-tone device can be configured to employ an approximation technique for determining areas of overlap regions produced by adjacent device spots in a printed halftone image based on a halftone device model. The approximation technique enables consideration of the effects of a variety of halftone device characteristics such as addressability, device spot size, and color values on the appearance of a printed halftone image. The system and method can be configured to employ the approximation technique in a manner that also enables consideration of the effect of misregistration between color separations on the appearance of a printed halftone image. As an alternative, the system and method can be configured to employ a geometrical abstract that effectively centers device spots on the corners of addressable units. This "corner-centered" addressing enables a computationally faster calculation of overlaps when used with either the approximation technique or an analytical technique based on geometric relationships, particularly for device spot diameters between a factor of .sqroot.2 and 2 of the addressability of the halftone device. Finally, the system and method may incorporate a technique for scaling the addressability of color values representative of the halftone printed image without introducing significant artifacts.
摘要:
A method for adjusting a color in a color space comprises adjusting the color along a gradient path to a point in or on a color gamut. The gradient path is determined from a potential field derived from the color gamut consisting of gamut points in the color space. The potential field can be derived from one or more points in the color gamut and different functions may be used to determine the potentials due to different points in the gamut. The potential at a point in the color space due to the gamut point can be a function, including an inverse power, of distance of the point in the color space from the gamut point. The gradient path can be determined from the gradient of the potential field by quadric error-based surface simplification of a surface mesh representing a surface of the gamut.
摘要:
Modification of color values in a page description file can be carried out by converting implicit color commands within the page description file to explicit color commands. The color values specified by the explicit color commands within the page description file then are adjusted to calibrate an output device for enhanced color fidelity. Implicit color commands specify color values indirectly, for example, by defining color as a function of other graphic information and color reference values. Consequently, color modification prior to RIP conversion generally is difficult. Conversion and modification of explicit color values provides a higher degree of color conversion accuracy without the need for RIP conversion of the page description file.
摘要:
A method for converting CMYK source device values to CMYK destination device values includes converting the CMYK source device values to a four-color device-independent color space using a source profile with a four-color device-independent color space. The four color device-independent color space is converted to the CMYK destination values using a destination profile with the four color device-independent color space, and three colors of the four color device-independent color space are used to define the color of a combined CMYK values and the remaining device-independent color space color is used to define the color of only a K colorant.