Abstract: Color management which uses a color conversion LUT for transformation from an N-dimensional source device color space (N?4) to a destination device color space, in which the color conversion LUT is constructed in a two-step process. In the first step, an intermediate color conversion LUT is constructed that converts colors in a three-dimensional device-independent color space through a gamut mapping step and through an inverse destination device transform so as to obtain colors in the destination device color space. In the second step, the overall color conversion LUT is obtained by applying a source device transform to color combinations in the source device color space so as to obtain color values in the three-dimensional device-independent color space, and thereafter performing three-dimensional color look-ups in the intermediate color conversion table.

Abstract: The present invention provides for initializing a color appearance model (CAM) for use in a color management system (CMS), the CMS for performing an imaging task. Initialization parameters for the CAM are determined. The initialization parameters are based on information from a device profile and/or a viewing condition profile. The imaging task determines how the information from the device profile and/or the viewing condition profile is to be used for the initialization parameters. The CAM is initialized using the determined initialization parameters. The initialization parameters for the CAM are likely to result in more accurate transformation of color image data between a source device and a destination device.

Abstract: A method and apparatus for generating transform-based color profiles by a measurement-based Color Management System (CMS). The measurement-based CMS generates the transform-based profile wherein the measurement-based color system is parameterized by color data and procedures. The CMS may use a reference Profile Connection Space (PCS) loaded from a measurement profile, thus enabling user configuration of the generation process. The reference PCS may also be set to include a gamut that is appropriate for an eventual color-output device. In addition, a Gamut Mapping Model (GMM) used in the generation process is user-selectable as well as a Device Model (DM). The DM may also be supplied as a pluggable module. The CMS also features user-selectable mapping from an International Color Consortium (ICC) intent to a PCS profile and to a DM. The features of the CMS may be used in an application, stand-alone profiling tool or in an operating system utility.

Abstract: Managing color data to transform source color image data from a source device into destination color image data for rendering by a destination device, including accessing a source color data file corresponding to the source device, the source color data file containing source device color characteristic data, constructing a source color transform based on the source device color characteristic data contained in the source color data file, and applying the source color transform to the source color image data to transform the source color image data from a source device color space into interim color image data in an interim color space.

Abstract: Performing color management of color image data using a device transform by generating an identifier key based on contents of a color measurement profile for a color device, the color measurement profile containing measurement data corresponding to the color device, determining if a device transform corresponding to the identifier key is present in a device transform cache disposed in a persistent memory, loading, in the case that it is determined that a device transform corresponding to the identifier key is present in the device transform cache, the device transform into a program-accessible transient memory, generating, in the case that it is determined that a device transform corresponding to the identifier key is not present in the device transform cache, a device transform based on the measurement data in the color measurement profile, and storing the generated device transform in the device transform cache in correspondence with the identifier key, and transforming the color image data based on the dev

Abstract: The present invention relates to a color management method for controlling the amount of black ink used by a destination device with a black channel when converting colors from one of a plurality of source device color spaces to destination device color space. This conversion is accomplished by obtaining a black weight of a source pixel in the source device color space, transforming the source pixel into a color in color appearance space, and calculating destination values based on the color in color appearance space and the obtained black weight. In the case that the source device color space does not include a black channel, the black weight is obtained from a color purity of the source pixel. In the case that the source device color space is a device space including a K channel, the black weight is obtained from the K channel.

Abstract: Mapping color image data from a source color gamut to a destination color gamut, wherein the mapping includes identifying source color boundary regions in the source color gamut based on descriptor data provided in a source color descriptor data structure, and determining a position of each identified source color boundary region, identifying destination color boundary regions in the destination color gamut based on descriptor data provided in a destination color descriptor data structure, and determining a position of each identified destination color boundary region, and mapping the color image data from the identified source color boundary regions to the identified destination color boundary regions based on a correspondence between the determined positions of the identified source color boundary regions and the determined positions of the identified destination color boundary regions.

Abstract: A color descriptor data structure corresponding to a color device, the color descriptor data structure including a reference color data set corresponding to a reference boundary descriptor representing reference colors of the color device based on measured colors from a reference color target, a plausible color data set corresponding to a plausible boundary descriptor representing plausible colors of the color device which are observable, which encompass at least the reference colors of the reference boundary descriptor, and which include a whitest-white color and a blackest-black color, and a neutral color data set corresponding to neutral colors of the color device, the neutral colors extending in range from the whitest-white color to the blackest-black color.

Abstract: An overall color transformation is constructed from multiple ones of individual color transformation steps, the overall color transformation used by a color management system to transform colors from one color space to another. A sequence of sequential add operations is executed, each add operation adding a single one of the individual transformation steps to an intermediate transformation constructed from preceding add operations, and for each add operation returning at least one value which characterizes the add operation. The sequence of subsequent add operations is altered based on preceding ones the returned values.

Abstract: The present invention provides for initializing a color appearance model (CAM) for use in a color management system (CMS), the CMS for performing an imaging task. Initialization parameters for the CAM are determined. The initialization parameters are based on information from a device profile and/or a viewing condition profile. The imaging task determines how the information from the device profile and/or the viewing condition profile is to be used for the initialization parameters. The CAM is initialized using the determined initialization parameters. The initialization parameters for the CAM are likely to result in more accurate transformation of color image data between a source device and a destination device.

Abstract: Conversion of color data values from a rectangular coordinate system such as CIELab to a cylindrical coordinate system such as CIELCh using two one-dimensional look-up tables, one each for the C value and the h value. The one-dimensional look-up tables are accessed by defining a new variable ? as the absolute value of the ratio of b and a.

Abstract: The present invention relates to a color management method for the conversion of internal color appearance space color values to CMYK device values, by interpolating CMY values from a plurality of CMY to color appearance space lookup tables, wherein each CMY table is associated with a specific value of K. A target internal color value is received and the relative purity of that color is calculated in the CMY space. Next, a black generation value is calculated using the relative purity of the target color. Finally, one of the plurality of CMY lookup tables is selected based on the black generation value, and a CMYK value is provided based on an interpolation from the selected lookup table. In this way, the present invention is able to control the output K value in a color appearance space to CMYK conversion. Accordingly, colors across a wide relative purity range, including natural images, can be reproduced with better accuracy and higher quality.

Abstract: Performing color management of color image data using a device transform by generating an identifier key based on contents of a color measurement profile for a color device, the color measurement profile containing measurement data corresponding to the color device, determining if a device transform corresponding to the identifier key is present in a device transform cache disposed in a persistent memory, loading, in the case that it is determined that a device transform corresponding to the identifier key is present in the device transform cache, the device transform into a program-accessible transient memory, generating, in the case that it is determined that a device transform corresponding to the identifier key is not present in the device transform cache, a device transform based on the measurement data in the color measurement profile, and storing the generated device transform in the device transform cache in correspondence with the identifier key, and transforming the color image data based on the dev

Abstract: A system for adjusting the representation of a device's color gamut in color appearance space, comprising performing forward mapping of sample colors from a device-dependent space to a device-independent color appearance space to obtain forward-mapped device-independent values, obtaining mismatch values for perceived device-neutrals, each mismatch value being a difference between a forward mapped value for the device-neutral and a neutral axis of the color appearance space, and adjusting each forward-mapped device-independent value by utilizing the obtained mismatch value for each corresponding lightness level of device-neutrals in order to obtain an adjusted forward mapping. The adjusting of each forward-mapped device-independent value may be a full adjustment of each value, or a partial adjustment that is performed in either a linear or non-linear manner and that may be based on chroma, lightness, or both.

Abstract: Managing color data to transform source color image data from a source device into destination color image data for rendering by a destination device, including accessing a source color data file corresponding to the source device, the source color data file containing source device color characteristic data, constructing a source color transform based on the source device color characteristic data contained in the source color data file, and applying the source color transform to the source color image data to transform the source color image data from a source device color space into interim color image data in an interim color space.

Abstract: A metamerism-reducing color transformation in which a color value in a perceptual color space is mapped to a corresponding color value in a device dependent color space. Multiple different inverse transforms are applied to the color value in the perceptual color space, one each for respective ones of multiple different viewing conditions such as different viewing illuminants or different surround, thereby resulting in plural different target color values in a viewing condition dependent space. The plural different target color values in the viewing condition dependent space are subjected to regression analysis based on a spectral model of reflectance of device colors so as to calculate to a single color coordinate in device dependent coordinates that best fits the plural different target color values in the viewing condition dependent space. The regression analysis may be a weighted regression analysis.

Abstract: The present invention is directed to a mechanism of dynamically selecting a gamut mapping component for use in a color management system which transforms colors specified in image data from a first color space to a second color space, the method comprising automatically generating prediction information for use in selecting from a plurality of gamut mapping components, wherein the prediction information is based on determined gamut mapping preferences corresponding to at least one characteristic of the image data, and automatically selecting at least one of the plurality of gamut mapping components based on the prediction information.

Abstract: Creation of a reverse look-up table from a forward look-up table for a color device. Indexes to the forward look-up table span all possible color stimulus values for the color device in a device dependent color space. Outputs from the forward look-up table span a color gamut of corresponding color response values for the color device in a device independent appearance color space. The reverse look-up table maps a color response value in the device independent appearance color space to a color stimulus value in the device dependent color space. Indexes to the reverse look-up table span beyond the color gamut of color response values for the color device, and outputs from the reverse look-up table span beyond all possible color stimulus values for the color device.

Abstract: Managing color data to transform CMYK source color data from a source device into CMYK destination color data for rendering by a destination device, the CMYK source color data and the CMYK destination color data being comprised of color pixels represented by cyan (C), magenta (M), yellow (Y) and black (K) values, in which a source color profile and a destination color profile are accessed, the source color profile containing a source color transform and the destination color profile containing a destination color transform. A determination is made, for each pixel of the CMYK source color data, whether the pixel has a non-zero C, M or Y value.

Abstract: An overall color transformation is constructed from multiple ones of individual color transformation steps, the overall color transformation used by a color management system to transform colors from one color space to another. A sequence of sequential add operations is executed, each add operation adding a single one of the individual transformation steps to an intermediate transformation constructed from preceding add operations, and for each add operation returning at least one value which characterizes the add operation. The sequence of subsequent add operations is altered based on preceding ones the returned values.