Abstract: A method for performing color conversion between color profiles includes converting source device color profile values to destination device color profile values using one or more plug-in software modules to define intermediate profile connecting space (PCS) values used for the color conversion. A system for performing color conversion between source device color profile values and destination color profile values includes a color mapping system including a source device profile interpreter. A destination device profile interpreter, and a controller are coupled to the source and destination device profile interpreters, and one or more plug-in software modules executable by the controller to define intermediate profile connecting space (PCS) values used for the color conversion.

Abstract: A method for performing color conversion includes configuring a color transformer to perform black point scaling when converting image data from a source device to a destination device. Another method for performing black point adjustment while performing color management conversions includes determining a device independent black reference vector for a device that corresponds to a predetermined set of device dependent values for that device. Converting the device dependent values to device independent data and adjusting the device independent data based on the device independent black reference vector.

Abstract: Techniques are described for preparing halftone bitmap images for printing on inkjet printers. The techniques may involve exclusive use of low-density inks to reproduce highlight colors and means for reducing the amount of ink applied to the page within “solid” areas while maintaining complete coverage of these areas. The techniques may rely on the high addressability and larger ink palette of recent inkjet printers. For example, some inkjet printers offer seven ink channels: low and high density inks for the cyan, magenta, and black channels, and a single high-density yellow ink. In one embodiment, halftone dots within a bitmap image are separated into perimeter data and core data. The perimeter data is then associated with a low-density ink channel and the core data is associated with a high-density ink channel.

Abstract: 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 calorimetric 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.

Abstract: A color mapping method is used in transforming colors between color imaging systems. The method includes using forward transformation profiles that characterize the color imaging systems to generate respective sets of device-independent color values for the color imaging systems. Color conversions are calculated by recursively reducing differences between the respective sets of device-independent color values. Based on these color conversions, a color map is constructed that describes a relationship between the color imaging systems.

Abstract: 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.

Abstract: A method of characterizing a color imaging system is provided. The method comprises obtaining first data indicative of output of the color imaging system. The first data is processed, to yield second data, according to a color appearance model that varies in accordance with neutrality of colors indicated by the first data. Other methods are provided as well as systems and computer program products for characterizing color imaging systems and devices and for producing colors.

Abstract: A system and method for multi-dimensional color transformation apply constraints to the transformation function to preserve the presence or absence of particular color information while achieving high accuracy color match. With a constrained multi-dimensional color transformation (CMT), a destination device, such as a color proofer, can provide an accurate color match relative to a source or “target” device, such as a printing press, and preserve dot integrity. In particular, the constraints can preserve selected color information that is present in an image produced by the source device, and prevent addition of other selected color information that would not be present in the source device image. In a halftone imaging device, the constraints prevent the removal or addition of dots from and to the image produced by destination device.

Abstract: The invention provides a color processing method comprising determining whether a desired mapping between a first arrangement, including a first color device, and a second arrangement, including a second color device, exists, and automatically producing a mapping between the first arrangement and the second arrangement in the absence of such a desired mapping.

Abstract: The invention provides techniques for thinning halftone dots in a halftone dot bit map. A bit map filter may be used to thin the dots. For example, a target glyph may passed over the bit map. If any subsets of bits within the bit map match the target glyph, the subsets of bits can be replaced with bits defined by a thinned glyph. In this manner, the ink of a halftone print can be reduced in a manner that enhances the visual appearance of the print.

Abstract: Techniques are described for color management of halftone prints by direct modification of halftone dot perimeters within bi-level, halftoned bitmap images. According to the halftone print color management techniques, border pixels of the halftone dots are spatially selected to be turned on or off in order to appropriately shrink or grow the halftone dots. The bitmap image may be prepared to create both a halftone proof and printing plates. Therefore, contrary to conventional continuous-tone color management techniques, direct halftone bitmap modification minimizes dot structure differences between data used to produce a proof and corresponding printing plates. The perimeter of a halftone dot within a bitmap image is modified by applying a local threshold value to a distance mapped bitmap image. The bitmap image may be bipolar distance mapped (BDM) to allow for shrinking or growing of the halftone dots by varying a threshold value.

Abstract: Techniques are described for preparing halftone bitmap images for printing on inkjet printers. The techniques may involve exclusive use of low-density inks to reproduce highlight colors and means for reducing the amount of ink applied to the page within “solid” areas while maintaining complete coverage of these areas. The techniques may rely on the high addressability and larger ink palette of recent inkjet printers. For example, some inkjet printers offer seven ink channels: low and high density inks for the cyan, magenta, and black channels, and a single high-density yellow ink. In one embodiment, halftone dots within a bitmap image are separated into perimeter data and core data. The perimeter data is then associated with a low-density ink channel and the core data is associated with a high-density ink channel.

Abstract: In one embodiment, a display device includes an integrated color matching processor that processes color data to facilitate accurate color rendering on the display device. The integrated color matching processor can be internal to the display device or external to the display device. Either way the processor may receive color input, process the color input, and output altered color image data to the display.

Abstract: A method for producing halftone dot patterns involves generation of a halftone dot pattern one color channel as a function of the halftone dot pattern generated for another color channel. Placement of dots for one color channel in view of dot placement of one or more other color channels can enhance image quality, promoting improved spacing of dots among the halftone dot patterns generated for the overprinted color channels. Dot placement for a color channel may depend on the number of dots placed for color channels that precede it in the halftoning process. With improved dot spacing in view of inter-channel effects, an inter-channel dot placement method can reduce the incidence of mottle and other image artifacts, improving the visual appearance of the integrated image. A master threshold array may be used to produce halftone dot patterns for all color channels, but applied, in effect, on a shifted basis to promote improved inter-channel dot spacing.

Abstract: A method of characterizing a color imaging system is provided. The method comprises obtaining first data indicative of output of the color imaging system. The first data is processed, to yield second data, according to a color appearance model that varies in accordance with neutrality of colors indicated by the first data. Other methods are provided as well as systems and computer program products for characterizing color imaging systems and devices and for producing colors.

Abstract: Techniques for converting images defined by halftone bitmaps to continuous tone (CT) representations can better preserve geometric information from the original halftone bitmaps, enhancing the accuracy of CT proofs produced by lower resolution proofers such as inkjet and electrophotographic devices. The conversion techniques may involve the application of different conversion processes to text/linework and image regions of the bitmaps. For example, the conversion process for image regions may involve application of bandwidth limitation to remove halftone dot structures prior to downsampling. On the contrary, the conversion process for text/linework regions may exclude bandwidth limitation in order to preserve sharpness of text and linework.

Abstract: 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.

Abstract: 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.

Abstract: Predicting a reflectance spectrum of a photographic print based on data from a scanned color negative. The technique uses dye concentration, providing a channel-independent basis for the spectral model. The spectral model includes three conceptual sections: scanner and film models, a photographic printer model, and a photographic paper model. The scanner and film section converts digital data from a scan of a color negative on a calibrated scanner into predictions of the spectral transmittance for each pixel. The photographic printer section uses an exposure schedule and optionally a color temperature and computes the spectrum of the exposing illumination as a function of time. The photographic paper section converts the illuminated negative's spectral power first into dye concentration estimates and subsequently into a predicted reflectance spectrum for the simulated print.

Abstract: A color mapping method is used in transforming colors between color imaging systems. The method includes using forward transformation profiles that characterize the color imaging systems to generate respective sets of device-independent color values for the color imaging systems. Color conversions are calculated by reducing differences between the respective sets of device-independent color values. Based on these color conversions, a color map is constructed that describes a relationship between the color imaging systems.