Abstract:
A system and a method are provided for maintaining accurate visual color performance of displays. In particular, various embodiments of the present invention described herein provide a system wherein partial color certification is incorporated into the calibration procedure. In the event that the partial color certification is out of tolerance, a full certification procedure is performed. If the full certification procedure is out of tolerance, the calculated errors of the certification procedure are utilized to perform an update to a baseline profile for the display. The updated baseline profile can either replace the existing baseline profile or can be concatenated with the baseline profile to preserve the baseline behavior of the display.
Abstract:
According to an embodiment of the present invention, selective tristimulous corrections to device-independent coordinates are applied using a piecewise linear correction function. The piecewise linear correction function is defined such that a maximum of the piecewise linear correction function occurs at a boundary condition of a corresponding device-dependent color space, and the piecewise linear correction function is linearly reduced to zero or approximately zero as values in the corresponding device-dependent color space approach either a different boundary condition or a neutral axis. By having the piecewise linear correction function reduce linearly to zero or approximately zero, corrections to one region of color smoothly diminish and blend into the other regions of color, thereby substantially preventing the introduction of artifacts or image corruption due to the corrections.
Abstract:
In one embodiment a method includes obtaining a white point correction for a display device and obtaining a chromatic correction for the display device. The method may also include generating corrected color coordinates based on the white point and chromatic corrections. The method may ensure that images that appear on a display device in a soft proofing environment will be visually equivalent to images that appear on print media.
Abstract:
A technique for profiling a color printing device employs a modified Neugebauer color mixing model. The modeling technique makes use of a variable dot gain value and “n factor.” The variable dot gain adjustment value may vary according to the particular tristimulus channel under evaluation. In addition, the variable dot gain value may vary according to the particular Neugebauer primary over which a halftone dot is printed. Accordingly, the technique may rely on an array of different dot gain values and n factors that correspond to different combinations of color channels and overprint conditions. As a further feature, the techniques may rely on a dot gain formula that relates halftone dot variation, i.e., fringe thickness, to the size of the halftone dot. This relationship tends to produce a dot gain model that more closely resembles the actual dot gain behavior on a printing press.
Abstract:
The disclosure is directed to techniques for gamut mapping with modified black point compensation (BPC). The gamut mapping techniques promote well-distributed tone compression so that substantial loss of detail in highlight and shadow regions can be avoided. The gamut mapping techniques may be particularly useful in converting rich saturated images, such as RGB photographs, for presentation as much less saturated output, such as typical newsprint. Other example applications include conversion of CMYK Specifications for Web Offset Printing (SWOP) printing to CMYK Specifications for Newsprint Advertising Production (SNAP) newsprint, and conversion of RGB photos with camera profiling software to CMYK for all types of printing.
Abstract:
In a system and a method for profiling a digital-image input device, profiling of the digital-image input device is performed based at least on an image of a color chart and an estimated illumination of the color chart generated by comparing illumination of device-dependent coordinate values for the image of the color chart with illumination of device-independent coordinate values of the color chart. Because the estimated illumination of the color chart is performed on data pertaining to the color chart, the present invention may generate a profile without reference to data pertaining to scenery in the image outside of the color chart. Consequently, the present invention may generate a profile irrespective of the relative exposure of the color chart with respect to other scenery in the image.
Abstract:
Techniques for providing accurate output measurement and calibration in soft proofing systems incorporate one or more features to promote controlled viewing conditions. For example, a soft proofing system is described in which an administrator can control the proofing process by limiting or restricting the ability to view an image until acceptable viewing conditions have been met. For example, the ability to view the image can be restricted until the viewing station has been calibrated using a calibration device known to support calibration of the viewing station to less than or equal to a maximum magnitude of error. With controlled viewing conditions and, more particularly, controlled calibration conditions, the soft proof reviewers obtain more uniform output. In this manner, the system can provide safeguards to ensure that the images viewed at the viewing station have acceptable color accuracy.
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:
An imaging technique permits selective flattening of objects within page description files. The selective aspect of the flattening may pertain to the selection of particular objects to be flattened, selection of the degree of flattening to be applied to objects, or both. In some embodiments, selective flattening of objects in a page description file may be permitted based on an assessment of color correction efficacy. For example, the degree of flattening may be iteratively adjusted to achieve acceptable color correction results. Alternatively; a user may be notified in the event acceptable color correction results have not been achieved. A color error between bitmap files generated from a color corrected, unflattened page description file and from a color corrected, flattened page description file may be measured. When the measured error between the two bitmaps exceeds a predetermined value, an amount of file flattening may be adjusted to reduce the measured error.
Abstract:
Improved color image display accuracy can be achieved across a computer network by obtaining information characterizing the color response of display devices associated with a client residing on the computer network, and using the information to modify color images delivered to the client. The information may include a gamma estimate. In one embodiment, the gamma estimate is limited to only the green color channel, without reference to the gammas for the red and blue channels. In this manner, the gamma estimate concentrates on the most dominant color channel and avoids errors that can arise due to the red-blue imbalances that are highly prevalent in many display devices. The information can be obtained, for example, by guiding the client through a color profiling process that profiles the color response of the display device. For example, such guidance may take the form of a series of instructional web pages that are delivered to the client. The web pages can be made interactive to enable collection of color characterization data from the client.