Eastman-kodak Company

Gustav J Braun

Kevin Edward Spaulding

Douglas W Couwenhoven

Peter D Burns

John R D'Errico

Kurt Michael Sanger

Geoffrey John Woolfe

Andrew Charles Gallagher

Jiebo Luo

Raymond William Ptucha

Paula J Alessi

Christophe E Papin

David W Bishop

Donald M Reiman

Kurt M Sangerl

A method for determining a blended color transform for use in producing printed colors on a color printer having at least four device color channels, comprising: forming first and second color transforms, wherein the first color transform produces printed colors that have a reduced sensitivity to color printer process variations in at least a first region of color space that includes a near-neutral color region, and wherein the second color transform produces printed colors that have a reduced image noise visibility in at least a second region of color space; defining a blending function which computes weighting values for the first and second color transforms as a function of input color values; and using a processor to determine the blended color transform by blending the first color transform and the second color transform, responsive to the blending function.

Color transform insensitive to process variability

A method for adjusting dot-gain for a halftone binary bitmap file comprises inputting a halftone binary bitmap file consisting of binary pixels () to an asymmetric digital filter (). The binary pixels are filtered with the asymmetric digital filter and generates multi-level pixels (). The multi-level pixel are compared to a preset level () and generates a binary pixel output (). The binary pixel output is collected and forms an adjusted halftone binary bitmap file ().

Asymmetrical digital filters for dot gain adjustments

A method for modifying an input digital image having one or more color channels, each color channel having an (x,y) array of image pixel values, to form a modified digital image so that when the modified digital image is used to produce a printed image on an inkjet printer there are reduced ink bleed artifacts.

Reducing ink bleed artifacts

Method for building color transforms for color imaging devices having concave color gamut regions, including forming a device model that relates device control signals for a color imaging device to corresponding device-independent color values in a device-independent color space; forming a device color gamut representing the set of colors in the device-independent color space that are producible by the color imaging device; and forming a convex color gamut by fitting a convex hull to the device color gamut. The method further includes forming an expanded device model that relates device control signals for the color imaging device to expanded device-independent color values in the device-independent color space, such that the expanded device-independent color values fill the convex color gamut; and building a color transform that relates input device-independent color values to corresponding device control signals for the color imaging device using the expanded device model.

Color transforms for concave device gamuts

A method for determining colorant control values for a color imaging device having four or more colorants is disclosed. The method includes defining a color mapping for a set of paths through a three-channel color space, defining a color mapping function for the three-channel color space relating the three-channel color space values to colorant control values for the four or more colorants of the color imaging device by interpolating between the color mapping defined for the set of paths, forming a forward three-channel color model relating the three-channel color space values to device-independent color values, inverting the forward three-channel color model to determine an inverse three-channel color model relating the device-independent color values to the three-channel color space values, and combining the inverse three-channel color model and the color mapping function to determine an inverse device color model.

Colorant control values for color printing devices

A method for multi-level halftoning an input digital image to form an output digital image which includes a multi-level error diffusion halftoning process incorporating periodic dither signals whose amplitudes are adjusted as a function of the error-diffusion texture characteristics.

Multi-level halftoning providing improved texture uniformity

A method for determining a set of n-dimensional colorant control signals that map to a point P in an m-dimensional color space where n&#x3e;m, including determining a forward device model that maps n-dimensional colorant control signals to m-dimensional color space signals; determining a set of n-dimensional colorant control signal simplexes that span a domain of the forward device model; and determining a set of range space simplexes in the m-dimensional color space corresponding to the set of n-dimensional colorant control space signal simplexes by mapping the vertices of the n-dimensional colorant control signal simplexes into the m-dimensional color space using the forward device model. The method also includes specifying a point P in the m-dimensional color space; and determining the set of n-dimensional colorant control signals that map to the point P in the m-dimensional color space, by performing m sequential slicing processes through the set of range space simplexes.

Determining sets of n-dimensional colorant control signals

A method for converting an original halftone bitmap image to a color converted halftone bitmap image. A set of asymmetrical morphological filters is provided. The original halftone bitmap image is segmented into blocks and for each block: apply the set of morphological filters to the original halftone bitmap image to produce a set of modified halftone bitmap images; estimate the percent dot area of the original halftone bitmap image and the set of modified halftone bitmap images; a predetermined dot-gain to the percent dot area of the original halftone bitmap image to produce a modified percent dot area; select the modified halftone bitmap image whose percent dot area is closest to the modified percent dot area to produce a block of the color corrected halftone bitmap image; and replace the original halftone bitmap image with the combined blocks of selected modified halftone bitmap image.

Halftone dot-growth technique based on morphological filtering

A method of processing a digital image having pixels to improve the sharpness of a print generated from the digital image including determining a magnification value representing the magnification of a pixel of the digital image on the print based on the number of input digital image pixels and the output number of digital image pixels; producing a filter in response to the magnification value; using the filter to operate on the digital image to adjust the sharpness of the digital image to produce a sharpened digital image; resizing according to the magnification value the sharpened digital image to produce a resized sharpened digital image which includes the output number of digital image pixels; and producing the print based on the resized sharpened digital image.

Sharpening a digital image in accordance with magnification values

A method of characterizing a display having a plurality of color channels includes the steps of visually characterizing the nonlinearities of the display; determining luminance ratios of the color channels using heterochromatic photometry; determining the chromaticities of the color channels using a neutral identification process; and calculating a colorimetric mixing matrix for the display by combining the luminance ratios of the color channels with the chromaticities of the color channels.

Visual display characterization

A method of selecting a preferred colorant control signal vector for a color output device for reproducing a desired output color, the color output device producing output colors using four or more colorants, wherein the amount of each colorant is controlled by the colorant control signal vector, includes determining a device model for the color output device relating the colorant control signal vector to the corresponding output color; using the device model to determine a set of valid colorant control signal vectors whose corresponding output color substantially matches the desired output color; and selecting the preferred colorant control signal vector from the set of valid colorant control signal vectors using a cost function responsive to one or more cost attribute(s) that vary as a function of the colorant control signal vector.

Calibrating a digital printer using a cost function

A method of generating a reduced color gamut boundary for a color output device using three or more colorants, wherein the amount of each colorant is controlled by a colorant control signal vector, including determining a forward device model for the color output device relating the colorant control signal vector to the corresponding output color; determining a complete color gamut boundary for the color output device, comprising a set of color gamut boundary points; and determining a set of candidate colorant control signal vectors for each point in the complete color gamut boundary. The method also includes selecting a preferred colorant control signal vector.

Color gamut mapping using a cost function

A method for processing a digital color image for display and transmission includes the steps of (a) resizing the image to a lower display resolution to produce a display-sized image, (b) quantizing the display-sized image to a display palette with an error diffusion process to produce an error diffused image, (c) losslessly compressing the error diffused image to produce a compressed image having a particular file size, (d) comparing the file size to a maximum file size and if less than the maximum file size, transmitting the digital image to the display; (e) if the file size is greater than the maximum file size but less than a another predetermined file size, reducing the error diffusion rate by a predetermined amount in order to reduce the file size; and (f) if the file size is greater than the maximum file size and the predetermined file size, simplifying the resized image by reducing image detail to produce a simplified image and repeating the preceding steps on the simplified image.

Method and system for generating digital image files for a limited display

A method for color correcting an original halftone bitmap image by a predefined color correction function to produce a color corrected halftone bitmap image comprising: providing an original halftone bitmap image; estimating the dot area percentage of the original halftone bitmap image in a set of sub-image blocks; calculating an aim dot area percentage, based on a predefined color correction function, for each sub-image block in the original halftone bitmap image, calculating the number of halftone bitmap image pixels to convert to on or off states to produce a modified original halftone bitmap image that has the aim dot area percentage where said value is designated by N, for each sub-image block in the original halftone bitmap image, and converting N pixels in the original halftone bitmap image to either on or off states depending on whether the aim dot area percentage is greater or less than the dot area percentage of the original halftone bitmap image respectively, for each sub-image block in the original halftone bitmap image.

Growing community of inventors

Fairport, NY, United States of America

Gustav J Braun