A method for halftoning an image, including receiving image data including a plurality of color separations and comparing image data for first, second, third, and fourth separations to first, second, third, and fourth halftone screens. The screens are characterized by first, second, third, and fourth pairs of frequency vectors, respectively. The fourth pair of frequency vectors is identical to one of the first, second, and third pairs of frequency vectors. Further, the first, second, third, and ...

A halftone screening method creates screens of a plurality of colors, where each of the screens is divided into a plurality of cells, and intentionally changes a dot position of certain colors within cells of the screens of the certain colors relative to a dot position of a reference color within a cell of the screen of the reference color, so as to suppress a color tone change caused by positional errors of the screens.

A continuously variable screening tool is used to generate a unique texture pattern for every color in a multicolor image. The continuously variable screening tool allows a single colorant version of the image to be generated with less information loss than typically suffered in the multicolor to single color transformation process. The continuously variable screening tool is generated by blending patterns from a set of reference screens. The reference screens are associated with selected refere...

The screened printing data are subjected to a filtering method, the raster information being maintained. Intermediate tonal values are produced by the filtering method, using the binary tonal values, the intermediate tonal values being configured in such a way that, by means of a color space transformation, transformed tonal values and/or intermediate tonal values can be formed which represent a true-to-color proof.

The present invention provides a system and method for digital image compensation wherein the image is divided into tiles, at least one of the tiles employing a rectfill. Compensation is provided by reducing the size of the rectfill at the edges by half a pixel all around. As a result, any minor overlaps of adjacent pixels are eliminated, resulting in only the correct pixels being filled.

In a matrix area (720), a plurality of highlight-side dot centers (731) and a plurality of shadow-side dot centers (741) are regularly arranged and a plurality of reference points (751) are set while being distributed almost uniformly. Each of the dot centers (731, 741) is rotated about a nearest reference point (751). Threshold values of the matrix area (720) are determined so that halftone dot areas should be changed around a plurality of highlight-side dot centers (731) after being rotated in...

A method is described of compositing a plurality of graphical objects to create an image comprising a plurality of parts, where the parts may be a run of pixels along a scanline or a region of the image. For each part of the image to be composited, the method identifies a set of the graphical objects that contribute to the part, and determines one or more required bit depths for compositing the set. The set is composited within the part at the one or more required bit depths. Thus selected parts...

A computer program and method for generating from a 1-bit image data file a multiple-bit image data file, which, when displayed on a computer display screen, resembles an image that would appear on an output medium as a result of an output device printing the 1-bit file, the program being operable to carry out, and the method comprising, the steps of: receiving a 1-bit image data file and first and second values that characterize actual regions of the output medium that would be marked by the ou...

Moire free color halftoning is achieved through the use of two dot screens and one or two line screens. The line screens may be, for example hybrid line screens. Frequency vectors associated with the screens combine to produce moire frequency vectors representing moire frequencies above or below the visual range. In one embodiment lines screens are used to halftone yellow and black separations and dot screens are used to halftone cyan and magenta separations. The dot screens are oriented at 15 a...

A color image forming device and method prevent occurrence of pile height moires specific to electrophotographic images in low-frequency areas and conventional moires in a digital screen set of four colors. In the color image forming device, by at least one of a halftone generating part and scanning signal forming unit in an image processing unit, differences among screen angles of three dot patterns corresponding to cyan, magenta and black toner images are in the range about 25 to 40 degrees, p...