Abstract: A halftone raster image, suitable for rendering a continuous-tone image, which comprises a plurality of regularly tiled spiral dots. Said spiral dots comprise (i) image pixels arranged as a first arc (200) or as a plurality of arcs which together represent a first spiral (100), and (ii) non-image pixels arranged as a second arc (201) or as a plurality of arcs which together represent a second spiral (101), wherein neighbour halftone dots from said plurality of regularly tiled halftone dots represent a double spiral or triple spiral.

Abstract: A method to encode and decode a digital fingerprint code by an identification encoder and an identification decoder wherein the digital fingerprint code includes a plurality of N-bit data embedded on a set of curves by changed thicknesses in the curves.

Abstract: A halftone raster image suitable for rendering a continuous-tone image includes a plurality of spiral dots. The spiral dots include image pixels arranged as a first arc or as a plurality of arcs which together represent a first spiral, and non-image pixels arranged as a second arc or as a plurality of arcs which together represent a second spiral. The spiral dots enable a controlled spreading of the ink within the dot, resulting in a higher image quality, ink saving, and faster drying.

Abstract: A halftone raster image, suitable for rendering a continuous-tone image, which comprises a plurality of dots, arranged according a screen ruling and screen angle. Said dots comprise (i) image pixels arranged as a first arc or as a plurality of arcs which together represent a first spiral, and (ii) non-image pixels arranged as a second arc or as a plurality of arcs which together represent a second spiral. Small displacements of the feed point of said dots away from the theoretical centre of a halftone dot, defined by said screen ruling and screen angle, enable a higher image quality and less patterns in said halftone raster image.

Abstract: A method of digital halftoning a continuous tone image into a halftone raster image having halftone cells wherein each halftone cell has a shape; wherein the method comprises the step generating a halftone dot in said halftone cell with a threshold array for determining non-image pixels and image pixels in said halftone cell and wherein said non-image pixels represent a first closed contour and image pixels represent a second closed contour; and wherein said first closed contour and/or second closed contour has a morphologic image processed shape from the shape of said halftone cell and wherein the halftone cells are arranged according to a periodic tessellation using a tile wherein each halftone cell has one or more edges which is not straight.

Abstract: A raster image processor (RIP) for digital binary halftoning a continuous tone image (CT) by a threshold tile (TT) into a halftone raster image (RT) for a printing device capable of printing on a plurality of substrates (S1, S2, . . . , SM); wherein said processor comprises an input field in which information regarding a substrate is to be used; a memory having stored thereon a plurality of threshold tiles (TT1, TT2, . . . , TTN) for generating regularly tiled halftone dots; and a threshold selector which is capable to select said threshold tile (TT) of said plurality of threshold tiles (TT1, TT2, . . . , TTN) based on information supplied to the input field.

Abstract: A halftone raster image, suitable for rendering a continuous-tone image, which comprises a plurality of regularly tiled spiral dots. Said spiral dots comprise (i) image pixels arranged as a first arc (200) or as a plurality of arcs which together represent a first spiral (100), and (ii) non-image pixels arranged as a second arc (201) or as a plurality of arcs which together represent a second spiral (101), wherein neighbour halftone dots from said plurality of regularly tiled halftone dots represent a double spiral or triple spiral.

Abstract: A method of reproducing a continuous-tone image with a printing press comprises the step of making a printing plate having a halftone raster image comprising regularly tiled halftone cells which consist of a grid of image pixels and non-image pixels; the halftone cells are obtained by digital halftoning with a single threshold array and at least a portion of the halftone cells in the raster image comprise multiple image clusters, image clusters being defined as mutually separated groups of more than 4 adjacent image pixels; the image clusters allow to obtain a printed image of the same image density with less ink than with conventional screens wherein the image pixels are grouped into a single cluster.

Abstract: A halftone raster image, suitable for rendering a continuous-tone image, which comprises a plurality of dots, arranged according a screen ruling and screen angle. Said dots comprise (i) image pixels arranged as a first arc or as a plurality of arcs which together represent a first spiral, and (ii) non-image pixels arranged as a second arc or as a plurality of arcs which together represent a second spiral. Small displacements of the feed point of said dots away from the theoretical centre of a halftone dot, defined by said screen ruling and screen angle, enable a higher image quality and less patterns in said halftone raster image.

Abstract: A method for manufacturing a security document including a security pattern generation method includes the steps of selecting a bounding region, an image object, and a raster image or a function; cutting the image object into image object partitions; and repeating the image object as a pattern, preferably a lattice pattern, in the bounding region wherein each of the image object partitions of an image object is transformed depending on the position area of the image object in the lattice pattern and the rank of the image object partition.

Abstract: A method for manufacturing a security document including a security pattern generation method includes the steps of selecting a bounding region, an image object, and a raster image or a function; cutting the image object into image object partitions; and repeating the image object as a pattern, preferably a lattice pattern, in the bounding region wherein each of the image object partitions of an image object is transformed depending on the position area of the image object in the lattice pattern and the rank of the image object partition.

Abstract: A security pattern generation method includes generating a plurality of draw instructions to define a plane filling line pattern, wherein the plane filling line pattern includes a repeating sub-pattern that defines a line by a sequence of draw instructions, and searching the sequence of draw instructions in the plurality of draw instructions and, if found, overlaying the searched sequence of draw instructions by a graphic object that is scaled to fit and scaled between the two distinct end points of the line.

Abstract: A method to encode and decode a digital fingerprint code by an identification encoder and an identification decoder wherein the digital fingerprint code includes a plurality of N-bit data embedded on a set of curves by changed thicknesses in the curves.

Abstract: A method to encode and decode a digital fingerprint code by an identification encoder and an identification decoder wherein the digital fingerprint code includes a plurality of N-bit data embedded on a set of curves by changed thicknesses in the curves.

Abstract: A method and a system for determining a characteristic of a printing system, the printing system including a printing device and a receiving substrate. Data from a pattern printed on the receiving substrate by the printing device are analyzed. Based on the analysis, an artifact characteristic of the printing system is determined automatically.

Abstract: A method for generating a bitmap from an image for image reproduction, the bitmap having both screened and non-screened data, includes the steps of: generating a set of contiguous microdots of the bitmap, wherein the set is selected from the group of a set of contiguous microdots forming an image dot being part of the screened data and a set of contiguous microdots forming an entity of contiguous microdots being part of the non-screened data; generating a non-printing dot in the set of contiguous microdots, depending on a specific characteristic selected from a characteristic of the image and a characteristic of the set of contiguous microdots; and applying a morphological filter to the set of contiguous microdots for preserving fine details in the reproduction of the image.

Abstract: A method and a system for determining a characteristic of a printing system, the printing system including a printing device and a receiving substrate. Data from a pattern printed on the receiving substrate by the printing device are analyzed. Based on the analysis, an artifact characteristic of the printing system is determined automatically.