Hewlett-packard Development Company, L.P.

Hewlett-packard Indigo B.v.

Landa Labs (2012) Ltd.

Tamar Kashti

Mani Fischer

Jan Philip Allebach

Carl Staelin

Oren Haik

Omri Shacham

Benzion Landa

Michael Nagler

Tal Frank

Ofer Aknin

Nir Rubin Ben Haim

Ronen Yogev

Madhur Gupta

Puneet Goyal

Itai Tzur

Doron Shaked

Dror Kella

Gidi Amir

Yung-Yao Chen

David Savelzon

An imaging device for projecting individually controllable laser beams onto an imaging surface movable in an X-direction. The device includes a plurality of semiconductor chips each comprising a plurality of laser beam emitting elements arranged in a main array of M&#xb7;N. The chips are mounted such that each pair of adjacent chips in the Y-direction are offset from one another in the X-direction and, if activated continuously, the emitted laser beams of the two chips of said pair trace on the imaging surface a set of parallel lines that are substantially uniformly spaced in the Y-direction. In addition to the M&#xb7;N elements of the main array, each chip comprises at least one additional column on one or each side, each additional column containing at least one selectively operable element capable of compensating for any misalignment in the Y-direction in the relative positioning of the adjacent chips on the support.

Imaging device

A system includes a structure module, graininess module, mottle module, and standard deviation (STD) module. The structure module is to identify a structure metric based on an input digital image, and remove a structured nonuniformity from the input digital image to produce a second input digital image. The graininess module is to identify a graininess metric based on the second input digital image. The mottle module is to identify a mottle metric based on the second input digital image. The STD module is to identify a STD metric that is to correspond to overall smoothness of the input digital image.

Metrics to identify image smoothness

A halftone screen may be used to transform a continuous tone image into a halftone image. Determining the halftone screen may include determining a first halftone tile for a first gray level, selecting pixel locations and increasing the intensity of pixels at the locations to activate the pixels to form a second halftone tile for a subsequent gray level. A filtered image may be generated from the second halftone tile, and pixels from the filtered image may be used to generate the halftone screen.

Halftone screen

A method and system to generate a moir&#xe9;-free to all-orders N-color screen-set by a lattice-based screen design the method including choosing a lattice in frequency space with basis vectors uand usuch that (&#x2225;{right arrow over (u)}&#x2225;,&#x2225;{right arrow over (u)}&#x2225;,&#x2225;{right arrow over (u)}{right arrow over (u)}&#x2225;)&#x3e;f min, where f min is the minimum moir&#xe9; invisible to the human eye, and choosing a set of N pairs of fundamental frequency vectors on the vertices of this lattice to be the screen vectors.

Lattice-based screen design for N-color all-orders moire-free screen set

A method for generating a clustered halftone representation of a continuous-tone image for printing includes applying a search technique. In the search technique, evaluation of a similarity between an initial halftone and the continuous-tone image includes application of an initialization filter to an initial error image that represents a difference between the initial halftone and the continuous-tone image. Evaluation of a similarity between each updated halftone, formed by modifying a previously-evaluated halftone, and the continuous-tone image includes application of an update filter that is different from the initialization filter to an updated error image that represents a difference between the updated halftone and the continuous-tone image. Relating computer program product and data processing system are also disclosed.

Clustered halftone generation

A method for predicting an appearance of a rendering by a printer of a digital halftone representation of a continuous-tone image includes calculating a predicted absorptance value of a dot of a rendered halftone of the digital halftone representation. The dot corresponds to a pixel of the digital halftone representation. The predicted absorptance value is based on a configuration of pixel values of pixels in an immediate neighborhood of the pixel, and on a weighted contribution of a pixel value of each pixel in an outer neighborhood of the pixel. The method may be incorporated into a halftoning technique. Relating computer program product and data processing system are also disclosed.

Method and system for enhancing a digital halftone representation for printing

A set of screens is provided for use in printing respective color separations in a halftone color printing process. This set of screens comprises at least two clustered-dot screens and the frequency and angle parameter values of the screens is such that the lowest frequency moir&#xe9; produced by any combination of at least two frequency components, taken from the group comprising the first and second screen harmonics, for which the sum of the harmonic orders of the frequency components in the combination is less than a predetermined value, is of a sufficiently high frequency as to be substantially unperceivable to the human visual system; other moir&#xe9;s are also substantially unperceivable to the human visual system. The lowest frequency moir&#xe9; serves to reduce the visibility of color changes caused by color plane registration variations. A printing system and method employing the screen set are also provided.

Reducing the visibility of color changes caused by color plane registration variations in halftone color printing

Growing community of inventors

Rehovot, Israel

Tamar Kashti