Abstract: A color calibration job identification system and method are provided, wherein the job identification data is encoded on a printed page, in a patch code, along with color targets, according to a protocol and format approximately identical to a format of the color targets. The patch code comprises a first portion, including a start code, and a second portion, including job identification data. The first portion of the patch code is comprised of two or more small color patches, each having a predefined color. The second portion of the patch code is comprised of two or more small color patches wherein each of the patches is comprised of a color selected from a plurality of colors, wherein each of the colors is indicative of a unique datum value, preferably an octal digit. The system provides a means for determining correct functioning of a printer and a means for determining an orientation of a printed page in a scanning device.

Abstract: A color marking device including a control system for calibration of the device based upon dynamic color balance control of an output image.

Abstract: A method for converting a specified color value from a first color space to a second color space identifies the specified color value in the first color space. A converted color space value is received from a final lookup table. The converted color space value is previously determined as a function of the specified color value and a mid-point interpolation and represents the specified color in the second color space. The converted color space value is stored in a memory device.

Abstract: A method and system validates an output used in calibrating a document processing system (DPS). The calibration target is generated for assessing the range of outputs of the DPS. The target comprises a plurality of target elements and element orientation information representing a physical layout of the target elements in a DPS output. The DPS output is generated in accordance with the calibration target. The characteristic values of the DPS output are measured corresponding to the individual target elements. If a mis-ordering of the measurements of the target elements is identified, the measurements of the target element of the DPS are reordered in accordance with the desired order for computing an appropriate calibration function without requirement of re-measurement.

Abstract: A pure rendering intent is used to render text and line art in color imaging systems. A CMY image goes through a one hundred percent under color removal process creating a CMYK image. The CMYK image is processed by a set of clamping tone reproduction curves. The clamping tone reproduction curves shift nearly saturated colors to total saturation. The result is a rendering of text and line art that has improved clarity and legibility.

Abstract: A color marking device includes a color balance controller which adjusts the TRC linearization in accordance with an intended illuminant for viewing the output of the device. The system comprises a front end converter for converting an input signal representative of a target image comprised to preselect the color into a device dependent control system in accordance with the device TRC. The device TRC is selected in accordance with a signal identifying the intended illuminant for the output.

Abstract: A color calibration job identification system and method are provided, wherein the job identification data is encoded on a printed page, in a patch code, along with color targets, according to a protocol and format approximately identical to a format of the color targets. The patch code comprises a first portion, including a start code, and a second portion, including job identification data. The first portion of the patch code is comprised of two or more small color patches, each having a predefined color. The second portion of the patch code is comprised of two or more small color patches wherein each of the patches is comprised of a color selected from a plurality of colors, wherein each of the colors is indicative of a unique datum value, preferably an octal digit. The system provides a means for determining correct functioning of a printer and a means for determining an orientation of a printed page in a scanning device.

Abstract: A color calibration job identification system and method are provided, wherein the job identification data is encoded on a printed page, in a patch code, along with color targets, according to a protocol and format approximately identical to a format of the color targets. The patch code comprises a first portion, including a start code, and a second portion, including job identification data. The first portion of the patch code is comprised of two or more small color patches, each having a predefined color. The second portion of the patch code is comprised of two or more small color patches wherein each of the patches is comprised of a color selected from a plurality of colors, wherein each of the colors is indicative of a unique datum value, preferably an octal digit. The system provides a means for determining correct functioning of a printer and a means for determining an orientation of a printed page in a scanning device.

Abstract: A color printing process, printing a color image in which out-of-gamut original colors are present. For each pixel defined by an original color which is determined to be out of gamut, a gamut remapping process is applied to map each pixel to a color which is within a printer gamut, remapping said pixels to colors within an output printer gamut. For a given set of gamut remapped pixels, gamut remapped pixel colors are compared with said original pixel colors, to derive a comparison metric. Using the comparison metric, a corrected set of gamut remapped colors is generated. The comparison metric may be subjected to an adaptive filtering process, which strengthens the comparison metric in high frequency image regions to increase its impact on the gamut remapped colors, and weakens the comparison metric in low frequency areas, to weaken its impact on the gamut remapped colors.

Abstract: A method for the automatic detection of colorimetry of CMYK image files includes the calculation of differentiation metrics based on colorant relationships, saturation, and luminance. Summary statistics, such as the means and standard deviations of the differentiation metrics are used to describe a set of known image colorimetry classes. At least one classifying algorithm is used to assign a known colorimetry class to an image of unknown colorimetry. Preferably at least one of the classifying algorithms is a Bayesian Quadratic Classifier algorithm. Mahanalobis distances are used to find the most appropriate colorimetry class to assign to an image. A color image processor operative to automatically detect image colorimetry comprises a training image analyzer, a colorimetry detector and a class associator.

Abstract: A method for determining and assigning colorimetry and authorship device information to an image of unknown colorimetry includes iteratively displaying the image on a display device and selecting possible source device profiles for transforming the image. When a possible source device is indicated or selected, the source device is emulated on the display device and the image is displayed through the emulation. A user can then evaluate the indicated source device and if necessary indicate a new possible source device. When the most likely source device is selected, further image processing is enabled. The method can be carried out on a color image processor comprising a source device emulator and display device interface. The display device interface can use a display device profile for profile connection space to display device transformation.

Abstract: A method of color transformation is based on non-separable tiling of a color space. Non-separable tiling allows fine granularity where it is desired and coarse granularity where it is tolerable. Non-separable tiling of the color space provides improved transformation quality for a given lookup table size. Color space is recursively tiled and addressed. Transformation information from the tiles is stored in a database. Database searching techniques are used to speed information access. For example, a hashing function and hashing table are employed to store and retrieve transformation information. An image processor operative to perform the method includes a database index generator and a database of transformation information. For example, the database index generator generates a hashing key from pixel information and uses a hashing function to generate a database cell index. The image processor includes an output device. The output device is, for example, a xerographic printer.

Abstract: A document processing system and a method for classifying an input image or region thereof as either a synthetic graphic or a natural picture, is disclosed. The system includes an image input subsystem, a processing subsystem for processing image data provided by the image input subsystem, and software/firmware means operative on the processing subsystem for a) low-pass filtering image data representative of the input image or region thereof to produce low-pass filtered pixel values; b) determining a smoothness value for each of a plurality of low-pass filtered pixel values; c) generating histogram data from the smoothness values; d) determining a texture metric for the input image or region thereof from a subset of the histogram data; and e) thresholding the texture metric to classify the input image as either a synthetic graphic or a natural picture.

Abstract: A method and color image processor for rendering a color image includes selective blending between transforms or rendering intents. Based on a pixels location within a color gamut of a first device the pixel is mapped to a color gamut of a second device as directed by a first transform or rendering intent, a second transform or rendering intent or a blend between the first and second transforms.

Abstract: A transformation function defines a relationship between a first color space and a second color space. The transformation function is edited by producing first and second outputs of an image in the first and second color spaces, respectively. The outputs are related in accordance with the transformation function. A portion of the first output, which corresponds to a portion of the second output including a color to be modified, is selected via a graphical user interface. A desired amount to modify the color is specified. A correction function is determined in accordance with the desired amount. The transformation table is edited in accordance with the monotonic correction function.

Abstract: A simplified color space transformation method uses a principal axis or dominating parameter in a first color space to determine the value of an associated axis in a second color space. Transformation curves relating the principal axis to the associated second space axis are predetermined and stored. Each curve describes the relationship between the principal axis and the associated axis given certain values for remaining, secondary or non-principal first color space axes. In operation the non-principal axes are used to calculate index values. For example, the non-principal values are quantized. The index values are used to access an appropriate curve. The principal axis value is used as an index into the appropriate curve. An image processor operative to perform the method comprises a transformation curve library.

Abstract: A method of adjusting an image production system to account for a variable property of a desired output medium includes storing a reference characterization of at least one measured value associated with a reference output medium. An output value, adjusted for the variable property of the desired output medium, is determined based on data including the reference characterization of the reference output medium, for example stored in color lookup tables, color rendering dictionaries, or the like. Based on the adjusted output value determined, the desired output medium is then printed or otherwise marked using the output value.

Abstract: A color printing process, printing a color image in which out-of-gamut original colors are present. For each pixel defined by an original color which is determined to be out of gamut, a gamut remapping process is applied to map each pixel to a color which is within a printer gamut, remapping said pixels to colors within an output printer gamut. For a given set of gamut remapped pixels, gamut remapped pixel colors are compared with said original pixel colors, to derive a comparison metric. Using the comparison metric, a corrected set of gamut remapped colors is generated. The comparison metric may be subjected to an adaptive filtering process, which strengthens the comparison metric in high frequency image regions to increase its impact on the gamut remapped colors, and weakens the comparison metric in low frequency areas, to weaken its impact on the gamut remapped colors.

Abstract: A method of color transformation is based on non-separable tiling of a color transformation lookup table. Non-separable tiling allows the lookup table to have fine granularity where it is needed or desired and coarse granularity where it can be tolerated. Therefore, non-separable tiling of the lookup table provides improved transformation quality for a given lookup table size. The non-separable tiles are enumerated. An appropriate tile is selected for use in a color transformation by finding an intersection between lists of tiles associated with each value that comprises a particular pixel. In one embodiment, a tile or transformation rule is associated with bit position in a bit vector. Any particular parameter value may be associated with one or more tiles or transformation rules. Therefore, a particular bit vector associated with a particular parameter value may have a plurality of set bits.

Abstract: A method for converting a specified color value from a first color space to a second color space identifies the specified color value in the first color space. A converted color space value is received from a final lookup table. The converted color space value is previously determined as a function of the specified color value and a mid-point interpolation and represents the specified color in the second color space. The converted color space value is stored in a memory device.