Sharp Laboratories of America, Inc

Sharp Kabushiki Kaisha Corporation

Sharp Laboratories of Ameirca, Inc.

James Zhixin Chang

John Charles Dalrymple

Chizu Watanabe

Xiao-Fan Feng

Jon Matthew Speigle

William C Kress

John Edward Dolan

John Dairymple

Chizu Inoue

Display characteristics are calculated using a first captured image for determining ambient light characteristics and a second captured image including the ambient light characteristics and the display characteristics by removing the ambient light characteristics from the second captured image, and display correction is performed based on the display characteristics. This can provide a device that saves time and effort such as moving a color-measurement device when correcting the display characteristics of one or more display devices and that is able to perform display configuration even if a large portion is illuminated by ambient illumination.

Display correction apparatus, program, and display correction system

A method is provided for gamut clipping with preprocessing enabled as software instructions stored in a computer-readable medium and executable by a processor. The instructions provide a color in a color space defined by at least three attributes. If the color lies outside a gamut boundary in the first color space, a distance is measured from the color to the gamut boundary. In response to the measured distance, a weight is calculated for an attribute of the color. Then, it is determined if the attribute of the color is to be shifted. If so, an attribute shift amount is derived. The attribute shift amount of the color is modified by applying the weighting. The attribute of the first color is shifted by the weighted attribute shift amount, creating a post-processed color. The post-processed color is then clipped.

Gamut clipping with preprocessing

Aspects of the present invention are related to systems, methods and apparatus for calibration of multiple display apparatus in a display ensemble.

Methods, systems and apparatus for jointly calibrating multiple displays in a display ensemble

Systems and methods for utilizing metadata embedded in a color measurement target to uniquely identify the target through color measurement. A color measurement target is used for color calibration, color characterization, color adjustment and/or color correction of a color output device and includes a collection of color patches imaged by the output device, wherein metadata is embedded directly into the color patches of the color measurement target to uniquely identify the target through color measurement. The metadata-bearing patches in the target are used to communicate information through color measurement, and can contribute to the color characterization.

Systems and methods for embedding metadata in a color measurement target

Aspects of the present invention relate to methods and systems for determining output responses and device targets for multi-colorant output devices. Some aspects relate to methods and systems for multi-dimensional rectilinear sampling, transformation of samples from an unlimited colorant space to a colorant-limited space, obtaining additional samples within a colorant-limitation hyperplane and interpolation of values in a colorant-limited space.

Methods and systems for sampling and modeling of colorant-limited, multi-colorant color spaces

A method for designing a black generation transfer curve is described. A table is produced to convert a first signal in a first signal space to a second signal in a second signal space. Color measurement data of a device is obtained. The color measurement data relates to a signal-to-color response of the device. A black generation transfer curve is designed constrained by the color measurement data of the device.

Systems and methods for designing a set of black generation transfer curves

Systems and methods for limiting total colorant in a color rendering system are disclosed. Implementation of the present invention provides for transformation of a specified colorant in which the sum of the colorant components exceeds a total area coverage (TAC) limit to create a second or resultant colorant in which the sum of the colorant components is within the limit. Using a bijective transformation, colorant sampling and other manipulations can be performed using a nominal hypercube space and the results can be compressed from the nominal space back to the actual colorant-limited space, simplifying manipulation of the colorant-limited polytope space. The unlimited colorant hypercube may be divided into simplexes. For each simplex, intersection points may be found between the TAC limit and the edges of the simplex. A barycentric interpolation technique may then be used to map the unlimited simplex onto a corresponding simplex within the colorant-limited polytope.

Method for limiting total colorant coverage using multidimensional simplicial subdivision and barycentric interpolation

Systems and methods for dynamically limiting total colorant coverage in multi-colorant rendering. Two polyhedra are defined: one contains all the colors that exceed the total colorant limit, and another is within the colorant limit that contains the results of the colorant limitation process. Data is received to identify a specified contone color, which is processed to decide whether it is inside one of the polyhedra. If the specified contone color is not within either polyhedra, the specified contone color is used in the rendering process. Alternatively, if the specified contone color is within one of the polyhedra, the value representing the specified contone color is compressed into the second polyhedra volume to obtain a resultant contone color that is used in the rendering process.

Systems and methods for dynamically limiting total colorant coverage in a color rendering system

Embodiments of the present invention comprise methods and systems for color gamut mapping. Some embodiments comprise mapping by projecting a first gamut color point to an intermediate curvilinear construct and then projecting from the curvilinear construct to a second color gamut point. In some embodiments, gamut points are separated into regions with differing projection rules and curvilinear constructs.

Methods and systems for color gamut adjustment

A method is provided for adaptively generating perceptually uniform printer characterization samples in a three-dimensional (3-D) signal space. The method comprises: generating lines, each including a plurality of samples, in a printer 3-D signal space; printing signal space color targets; measuring the signal space color targets; generating lines with a plurality of perceptually uniform samples; generating polygon shapes in the 3-D signal space from the perceptually uniform sampled lines; calculating addition perceptually uniform sample points associated with each polygon; and, generating a final target in the printer 3-D signal space using the calculated perceptually uniform sample points. In one aspect, generating lines, includes: for each line, generating a metric distance function; creating a plurality of perceptually uniform samples on the function output axis; and, using the inverse of the metric distance function, mapping perceptually uniform samples onto the line.

Adaptive generation of perceptually uniform samples for printer characterization

A method of color conversion includes providing a first color domain input signal set having plural input signals; sorting the input signals of the first color domain input signal set according to signal intensity; designing and generating plural 1-D look-up table sets for color polyhedrons; selecting a set of look-up tables for use with a specific color polyhedron, wherein said selecting is a function of a section of the polyhedron determined as a function of the input signal set; looking up values in the look-up table set as a function of the input signal set; generating weights as a function of the sorted signal intensities; and interpolating the output from the selected look-up tables as a function of the selected look-up table and the generated weights to produce a color domain signal set which is converted to a desired color domain signal set.

Color conversion with hue straightening using multiple look-up tables and interpolation

A method of determining colorant amounts to be laid down in a color printer includes determining an initial set of cyan, magenta and yellow (CMY) values; ordering the initial set of CMY values to determine the largest, middle and smallest values of the three values and generating an ordering vector; selecting a gamut center black generation LUT and two gamut boundary black generation LUTs from a set of black generation LUTs from a selection table; indexing the selected black generation LUTs to determine black values for each black generation LUT as a function of the minimum of the CMY values; interpolating a final output black colorant amount from the black values, and interpolating final output CMY colorant amounts from the initial set of CMY values, the maximum CMY ink limit constraint, and a set of boundary threshold values.

Black generation method for CMYK color printer using multiple lookup tables and interpolation

A method for background adjustment. A background lightness level in an original image is estimated. Pixels are then converted to a luminance-chrominance color space. Pixels have lightness levels equal to the background lightness level are mapped to a value corresponding to white as background pixels. Chroma values for the background pixels are compared to a threshold and adjusted as needed, either by adjusting the lightness value or by removing the chrominance values. The luminance-chrominance data is then converted to output space.

Method and apparatus for background adjustment in color reproduction devices

An imaging system includes an imaging sensing device sensing an object having a first background color and a backing in opposing relationship with the object having a second background color which is substantially the same as the first background color. The imaging system determines at least one general bounding region of the object based upon a shadow cast onto backing by the object.

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Vancouver, WA, United States of America

James Zhixin Chang