Abstract: In a color printing environment, functions for printing color management are dissociated. An abstraction layer is also provided to facilitate setting and evaluation of all factors relating to color print and prediction.

Abstract: In the generation of a threshold matrix for Nx speed writing, first and second areas are set, the first area being a cluster of a plurality of first partial areas substantially evenly distributed in a matrix space, and the second area being an area of the matrix space excluding the first area. Next, at least two writing elements in each of the first partial areas are allocated occurrence numbers and changed into determined elements. Then, at least one writing element in the second area is allocated an occurrence number and changed into a determined element. Thereafter, the other writing elements are allocated occurrence numbers and changed into determined elements. In accordance with the occurrence numbers, the threshold value of each writing element is determined to obtain a threshold matrix for Nx speed writing. This results in a reduction in the graininess of an image in a highlight area.

Abstract: An image processing apparatus includes an image processing command input section to receive image processing commands for image data written into a memory by units of one line, a line number deriving section to derive a number of lines of the image data required to execute image processing operations based on the image processing commands received by the image processing command input section, a line number indicating section to output a numerical value indicating the number of lines of the image data derived by the line number deriving section, a read timing controlling section to control read timing from the memory in response to the numerical value output from the line number indicating section, a parameter indicating section to output parameters used for the image processing operations, and an image processing section to execute the image processing operations.

Abstract: A color processing apparatus includes an obtaining unit, a setting unit, and a color converting unit. The obtaining unit obtains a predetermined corresponding relationship between total amount limit information regarding limitation of a total amount of inks of colors, and a combination in which, among droplet diameters of inks of colors ejectable to satisfy the total amount limit information, droplet diameters of at least two or more inks are made uniform, and the types of droplet diameters of inks of the colors are two or fewer types. The setting unit sets the combination of droplet diameters corresponding to the accepted ink total amount limit information, on the basis of the obtained corresponding relationship. The color converting unit converts a color in an input color gamut reproducible by an input device into a color in an output color gamut in accordance with the set combination of droplet diameters.

Abstract: An electrophotographic image output device includes an image processor to receive input image data, and a line screen to represent halftone images and have multiple screen angles respectively allocated to different colors including yellow, magenta, and cyan. The line screen satisfies requirements of (A) a predetermined difference is secured between adjacent two of the multiple screen angles; (B) zero is not allocated to any of the multiple screen angles; and (C) among the multiple screen angles determined by the requirements (A) and (B), a screen angle closest to 90 degrees is allocated to yellow among yellow, magenta, and cyan.

Abstract: An image forming apparatus includes a density conversion unit converting the density of one or more image data from among plural image data to be combined having different tones so as to correspond to the tone to be combined; a combine unit combining the plural image data by using the image data whose density is converted by the density conversion unit; and an image forming unit forming an image by using the image data combined by the combine unit.

Abstract: A control device performs: acquiring an optical measured scan value; setting a measured offset using the measured scan value by reference to predetermined correlations; and determining a control value using the measured offset amount. The control value is used for controlling an amount of colorant to be ejected during printing. In the predetermined correlations, a first pair of scan values is associated with a first pair of offsets. A second pair of scan values is associated with a second pair of offsets. The first and second pair has a first and second scan difference between the scan values, respectively. The first and second pair of offsets has a first and second offset difference between the offsets, respectively. The first scan difference is different from the second scan difference. The first offset difference is same as the second offset difference.

Abstract: A method of producing a bit-map including rendering a bit-map of a first image using a first stochastic half-tone screen set, rendering a bit-map of a second image using a second stochastic half-tone screen set, wherein the first half-tone screen set and the second half-tone screen set have respectively associated stochastic half-tone screens, and wherein each half-tone screen of the second half-tone screen set is less than 100 percent correlated with, and not an inverse of, the associated half-tone screen of the first half-tone screen set; and merging the bit-map of the first image with the bit-map of the second image.

Abstract: A contone source image is processed to create halftone outputs by identifying intensity thresholds based on the coordinates of the pixels of the source image. The halftone output corresponding to a particular pixel of the contone image in a particular color plane is determined by comparing the intensity of the pixel and any previously accumulated output error to the intensity threshold corresponding to the pixel.

Abstract: A method of operating a printer includes reducing a first plurality of coverage parameters in a first continuous tone (contone) pixel by a predetermined amount if a combination of at least two of the coverage parameters is below a predetermined threshold and reducing a second plurality of coverage parameters in a second pixel by a smaller amount if the combination of coverage parameters in the second pixel is greater than the predetermined threshold. The method further includes generating half-tone image data from the first and second pixels and forming printed marks corresponding to the first and second pixels on an image receiving surface.

Abstract: A system and method converts pixels of continuous image data to pixels of binary image data using a halftone screen corresponding to a predetermined reduced coverage percentage; determines if a target pixel of binary image data is a non-white pixel; compares a window of pixels of binary image data with a predetermined pattern of pixels of binary image data corresponding to the predetermined reduced coverage percentage; determines that the target pixel is a non-edge pixel; and reduces the number of non-white pixels in the binary image data based upon the determination that the target pixel is a non-edge pixel.

Abstract: There is provided an image processing device which converts multi-gradation pixels configuring a multi-gradation image of image data to be used in a color image forming apparatus, into unit dither patterns. The image forming apparatus includes photosensitive members on which developer images are formed by supplying developer to electrostatic latent images, and an exposure device which exposes the photosensitive members. The developer images on the photosensitive members are transferred to a transferred medium which is moved while contacting the photosensitive members. The image processing device includes a processing unit which converts a multi-gradation pixel of a first color into unit dither patterns, each unit dither pattern consisting of a first line extending in a predetermined direction and a second line extending in a direction intersecting with the first line when a gradation value of the multi-gradation pixel is within a predetermined range.

Abstract: An image processing apparatus comprises a first screen processing unit which applies screen processing to image data using a first threshold matrix; a second screen processing unit which applies screen processing to the image data using a second threshold matrix different from the first threshold matrix; an edge detection unit which detects an edge portion of an object included in the image data; and an output unit which selects and outputs image data obtained by a logical OR operation between image data obtained by the first screen processing unit and image data obtained by the second screen processing unit for a pixel detected by the edge detection unit as an edge portion, and selects and outputs the image data obtained by the first screen processing unit for a pixel other than the edge portion.

Abstract: A method and system to generate a moiré-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 u1 and u2 such that (?{right arrow over (u)}1?,?{right arrow over (u)}2?,?{right arrow over (u)}1±{right arrow over (u)}2?)>f min, where f min is the minimum moiré 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.

Abstract: A computer readable storage medium stores a tint block image generation program for generating tint block image data for forming, on a print medium, a tint block image including a latent image portion which is reproduced by copying, and a background portion of which copy output density drops. The program has a latent image portion generation step of generating data of a plurality of first dots in the latent image portion based on a dot clustered screen; and a background portion generation step of generating data of a plurality of second dots and data of a plurality of third dots dispersed among the second dots and having a size smaller than the second dots. And the first dots in the latent image portion and the second dots in the background portion are arranged at positions on common displacement vectors in an area of the tint block image.

Abstract: An image forming apparatus is provided. The image forming apparatus includes a communication interface unit which receives print data, a rendering unit which converts the received print data into a bitmap image by rendering, a binarization unit which generates binary data by carrying out halftoning with respect to the bitmap image, a data combining unit which generates multi-bit data by combining a plurality of successive binary data of the generated binary data, and a print engine which forms an image on a print paper using the generated multi-bit data.

Abstract: A contone source image is processed to create halftone outputs by identifying intensity thresholds based on the coordinates of the pixels of the source image. The halftone output corresponding to a particular pixel of the contone image in a particular color plane is determined by comparing the intensity of the pixel and any previously accumulated output error to the intensity threshold corresponding to the pixel.

Abstract: A method for extracting step and repeat data from a halftone printing job (200). De-screening a halftone image data on a computer (104) to create a de-screened image. The de-screening (512) is performed on a halftone image data stored in a computer storage (116). The halftone image data contains at least one step and repeat element (208). The de-screened image is scanned (516) to identify unique pixel segments (520). All instances of the found unique pixel segments are used to reconstruct (524) the step and repeat data previously used to create the halftone printing job (200).

Abstract: An image processing apparatus includes: a first colorant reducing unit that performs a first colorant reducing process that reduces colorant of black on second image data to output fourth image data representing tone values of the black separation on a per-pixel basis; a second colorant reducing unit that performs a second colorant reducing process that reduces the colorants of the colors other than black on a portion of third image data, the portion corresponding to the separations of the colors other than black, to output fifth image data representing tone values of each of the separations of the colors other than black on a per-pixel basis; and a combining unit that combines the fourth image data and the fifth image data to output sixth image data representing tone values of each of the separations of the colors including black on a per-pixel basis.

Abstract: An apparatus and a method are described for processing and reproducing a document including both text and half-tone images without generating undesirable image artifacts. A band-pass FIR filter with a predetermined frequency response is used to transform pixels in an input image to sharpen text edge and smooth pre-half-toned areas, and perform error diffusion and cluster dot screening methods on the transformed pixels. The FIR filter has unity gain at DC to preserve image brightness. An integrated error diffused cluster-dot screening approach is used to suppress moiré and other image artifacts, while providing a robust, crisp output.

Abstract: In a preflight process for digital print systems, color data from print data are analyzed and the results presented in a report. The color data are individually altered in regard to not only a color profile, in which they are encoded, but also in regard to their color values, using a graphic user interface. Results of the alterations are displayed using corresponding screened document pages.

Abstract: An image forming apparatus selects a screen from a plurality of screens corresponding respectively to a plurality of gradation values and each including a pattern in which a first region to which toner is to adhere and a second region to which toner is not to adhere are defined, and forms a toner image on media. The apparatus includes a storage device for storing a minimum formable distance between first regions or second regions adjacent to each other, and a controller calculating a distance between the first regions or second regions adjacent to each other in the screen and, when the distance of the region of a screen that corresponds to a gradation value of an input image and has a first pattern is smaller than the minimum formable distance, selecting a screen corresponding to the gradation value of the input image and having a second pattern.

Abstract: A first screen group and a second screen group are stored in an image forming apparatus. In the first screen group, the first region expands with increasing gradation value based on a first rule. In the second screen group, the first region expands with increasing gradation value based on an independent second rule different from the first rule. A screen selector relocates a first portion and a second portion such that the first portion and the second portion are joined by a second region that is not a toner adhesion control target, when the first portion and the second portion are adjacent as a result of the selection of the screen in each unit region of the input image. The first portion includes the screen included in the first screen group, and the second portion includes the screen included in the second screen group.

Abstract: Provided is a 3-colorant DOD (dot-off-dot) periodic halftone geometry used to render an image. The DOD 3-colorant halftone geometry includes a base colorant halftone screen with hexagonally tiled halftone dots arranged in a hexagonal pattern, the hexagonally tiled halftone dots having a first fundamental frequency vector Vh1, a second fundamental frequency vector Vh2, and a third fundamental frequency vector Vh3, where Vh3 is substantially equivalent to Vh1+Vh2.

Abstract: Dot patterns formed by two different half-tone processes of the plurality of tone processes for each color of CMYK and formed with/without the presence and absence of transparent toner overlap are created and test patches obtained by collecting the dot patterns are printed. The printed test patches are read to generate image data, and tone correction arithmetic is performed on the basis of the image data. Concentration in the case of the presence of transparent toner in a different half-tone process is predicted based on the dot patterns with the transparent toner overlap in the test patches and concentration in the case of the absence of transparent toner in a different half-tone process is predicted based on the dot patterns without the transparent toner overlap in the test patches. The tone correction arithmetic is performed based on the predicted values.

Abstract: A printing control device includes an input image data acquiring unit, a threshold acquiring unit, a determining unit, and a generating unit. The input image data acquiring unit acquires input image data. The input image data includes a plurality of input pixel data. Each input pixel data has an input value. The determining unit determines, for each input pixel data, a difference related value based on a difference between the input value and a threshold value corresponding to the input value. The generating unit generates print data by generating, for each input pixel data, output pixel data based on the difference related value. The output pixel data expresses density corresponding to the difference related value.

Abstract: An image glossiness controller has a main component color specifying unit that identifies a prescribed component color and output identification information thereof. A change in amplitude of a convexoconcavity of a toner layer of the prescribed component color is greatest among those of the other component colors when each of the component color toner is formed and fixed alone. Three or more halftone dot signal generators convert clear toner image information into three or more binary clear toner image signals corresponding to three or more component colors per component color pixel using multiple halftone dot characteristics, respectively. Each of the multiple halftone dot characteristics generating three or more binary clear toner image signals has a reversed phase from that generating three or more binary component color image signals.

Abstract: An image processing apparatus may include a first screen processing unit, a moiré component calculation unit, a first correction unit, and a second screen processing unit. The first screen processing unit performs screen processing on image data to form screen processed image data. The moiré component calculation unit calculates an original moiré component that corresponds to a low-frequency component of the screen processed image data and a low-frequency component of the image data. The first correction unit corrects the image data based on a calculated moiré component. The second screen processing unit performs the screen processing on the corrected image data.

Abstract: An image forming apparatus capable of reducing a stitch effect, an image forming system including the same, and a printing method thereof. The printing method of the image forming system includes inputting image data to be printed; and, if adjacent first and second objects included in the input image data have different LPIs (Lines Per Inch), emphasizing at least one of boundaries of the first and second objects and printing the image data with an emphasized boundary.

Abstract: A method for the digital screening of a halftone image by using a first screen having an arbitrary desired screen width and an arbitrary desired screen angle. For the method, the threshold value matrix of a second screen with a different screen angle and width is read out and compared with the color values of a halftone image presented. In order also to approximate screens having a particular irrational tangent and to avoid unpleasant sudden exposed device pixels in clear regions, it is proposed to provide at least one second threshold value matrix having X3Y3 addresses, the X3Y3 addresses of the second threshold value matrix are displaced by a factor 1/B in relation to the X2Y2 addresses of the first threshold value matrix, and to read out the second threshold value matrix as soon as an error D between the first and the second screen exceeds a predefined limiting value.

Abstract: A printing method, and an image forming apparatus and image forming system to perform the method, the method including performing a multi-bit halftoning of a pixel of image data if the pixel is to be printed with a dark developer, performing a single-bit halftoning of the pixel if the pixel is to be printed with a light developer, and printing the halftoned image data.

Abstract: A method for designing a screen set for color halftoning includes selecting a screen set that includes at least two screens. The screens are applied to a uniform color image so as to form a set of corresponding colorant halftones. The colorant halftones are superposed to form a color halftone. A spatial frequency spectrum of the color halftone is calculated. Maxima of the spatial frequency spectrum that occur at two effective frequencies are identified, the two effective frequencies being located in two adjacent quadrants of a complex spatial frequency space. A magnitude of each effective frequency is compared with a predetermined frequency magnitude. The screen set is accepted for future application for color halftoning only if both effective frequency magnitudes are greater than the predetermined frequency magnitude. Relating computer program product and data processing system are also disclosed.

Abstract: An image processing apparatus includes a correcting unit that performs enlarging or reducing correction on an image to be processed by determining an arrangement of pixels that are to be added to or deleted from gradational image data of the image to be processed based on an angle at which the pixels are to be arranged with respect to a horizontal direction of the image to be processed or with respect to a vertical direction of the image to be processed, and a pixel array control unit that changes the angle at which the pixels are arranged based on a test image of the image data to be processed after being corrected by the correcting unit.

Abstract: This presents an image processing apparatus and an image processing method which print and output image data subjected to halftone processing with an appropriate density characteristic. The image processing apparatus generates a halftone image from a multi-value image using a threshold value arrangement, and generates a difference image between the generated halftone image and a second halftone image having the density characteristic different from that of the generated halftone image. The image processing apparatus stores the generated halftone image and the generated difference image.

Abstract: Embodiments of the present invention provide techniques and configurations for error diffusion halftoning of an image including receiving a signal that indicates selection of a first implementation or a second implementation of determining a threshold perturbation value for error diffusion halftoning of an image, and determining the threshold perturbation value using a table of programmable values according to the selected one of the first implementation or the second implementation, wherein the second implementation provides fewer threshold perturbation values for a larger region of the image than the first implementation. Other embodiments may be described and/or claimed.

Abstract: It is determined whether the pixel of interest in image data to be processed belongs to area 1 not close to a scan line changing point where a scan line changing process is done (S101). If the pixel of interest belongs to area 1, an error diffusion process is performed using an error diffusion matrix for area 1 (S102). If the pixel of interest belongs to area 2 close to the scan line changing point, the error diffusion process is performing using an error diffusion matrix for downward scan line changing for area 2 when the scan line changing process is changing to a lower line, or an error diffusion matrix for upward scan line changing for area 2 when the scan line changing process is changing to an upper line.

Abstract: A method for screening color separations of a lenticular image having a lenticular frequency of lenticular lenses for viewing the image, with a lens width l. An amplitude-modulated halftone image is calculated for each color separation at one screen angle with a rational number tangent and screen frequency. The screen has non-orthogonal screen cells spanned by vectors u, v for a specific color separation. A distance k is defined. Directions of vectors u, v relating to perpendicular direction relative to image strips of the lenticular image are defined for the specific color separation. First (n, m) and second (i, j) pairs of rational numbers are defined, to satisfy a system of equations: n*ux+m*vx=0, n*uy+m*vy=1, i*ux?j*vx=k and i*uy?j*vy=0 for vectors u=(ux, uy) and v=(vx, vy) spanning screen cells. A computer program product is also provided.

Abstract: An image forming apparatus to save toner, which can increase the sharpness of printed data (for example, images or characters) on a printing medium while achieving toner saving, and a method to control the same. The image forming apparatus includes a determinator, a storage unit, and a halftoning processor. The determinator receives a command signal to print and then determines whether or not the received command signal is a command signal for a toner saving mode. The storage unit stores a halftone table in which an LPI higher than a normal LPI is set. If the received command signal is a command signal for the toner saving mode, the halftoning processor generates and outputs halftoning result by comparing gray level values corresponding to pixels of received input image data with grayscale values of the stored halftone table.

Abstract: A method of file preparation, ripping and plate making for high end graphics printed on cylindrical products utilizing Dry Offset printing presses. While utilizing two inverse angle techniques and one fixed angle on the Black, with virtually unlimited color pluralities, encompassing a majority of all open areas of the common printing blanket without any ink overlap. The nesting of the halftone dots at even coarse line screen rulings eliminating a dot rosette pattern and creating a continuous tone appearance. Print contrast is increased to that of offset printing quality and ink contamination over the course of the run length is virtually eliminated. This current invention also increases the ability to print white with colors as opposed to needing white coating done in advanced to transparent plastics and metallic surfaces.

Abstract: An image processing apparatus includes a screen processing unit that performs, on a color component basis, screen processing for a color signal having basic color components and at least one spot color component. The screen processing unit performs FM screen processing for one of the basic color components of the color signal and performs AM screen processing for the color components, other than the one of the basic color components, of the color signal with four types of screen angles.

Abstract: In a halftone image after halftone processing, significant dot values within a reference window that encompasses a pixel of interest are accumulated, and by referring to a conversion table based on the accumulated values, a multilevel pixel value that corresponds to that pixel of interest is restored. At this time, the size of the reference window is determined such that a product of a bit depth in the halftone processing and the number of pixels within the reference window becomes a minimum value that exceeds the number of tones in a multilevel image after restoration.

Abstract: A disclosed method for setting multiple tones in a halftone process upon recording an image using ink includes the steps of: dividing the image into plural dot areas; and setting the multiple tones such that at least one dot area to which the ink is not attached is present between dot areas to which the ink is attached.

Abstract: The present invention relates to a method and apparatus capable of generating frequency-modulation halftone dots in high speed and belongs to the field of the digital image halftone. In the prior art, read-write operation is usually carried out many times in error rows during processing each pixel so that halftone dots are generated in low speed. In the method according to the present invention, the error generated by the current pixel is buffered in a register file and the final accumulated error values are written in the error rows only after all of the relative pixels are processed. Thus, read-write operation is carried out only once in the error rows for processing each pixel. The present invention also provides an apparatus to implement the method. The apparatus comprises an error row memory, an error buffer register file, a gray generation circuit, a threshold comparison circuit, an error generation circuit, an error buffer register file control circuit, and an error row control circuit.

Abstract: A method of processing a continuous tone image includes using a halftone screen to generate a bi-level bitmap; partitioning the contone image into an array of image blocks; halftoning the image blocks; using the bi-level bitmap to select some of the halftone image blocks; and modifying the selected halftone image blocks using code words, such that information contained in the code words is embedded in a halftone image. A method of extracting embedded information in a halftone image includes accessing a bi-level bit map; partitioning the halftone image into a plurality of image blocks; using the bitmap to select at least some of the blocks; identifying a code word sequence in the selected blocks; and extracting the information from the code word sequence.

Abstract: A method for controlling an image processing apparatus includes obtaining image data from a detachable memory unit, estimating whether the obtained image data is image data read by a scanner, and in a case where it is estimated that the obtained image data is image data read by the scanner, performing control not to execute predetermined screen processing on the image data.

Abstract: Disclosed herein is an image processing apparatus including: a screen processor for determining each pixel value of a screen processing application unit region composed of a plurality of pixels to which a threshold matrix is applied, in an inputted image; and for carrying out a screen processing by applying one threshold matrix among a plurality of threshold matrices in which applied positions of the threshold values are different from each other, to the plurality of pixels in the screen processing application unit region based on each determined pixel value.

Abstract: 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 moiré 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 moirés are also substantially unperceivable to the human visual system. The lowest frequency moiré 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.

Abstract: A method and apparatus are provided for compensating for spatial non-uniformities in a printer by deriving a true spatial non-uniformity tone response curve (TRC) that characterizes the printer in terms of color output variation for each addressable pixel location in a spatial range. The “true average” tone response curve is determined for a color channel. A prediction of the true response as a function of the spatial location is derived by printing and scanning a specially designed halftone-independent target of binary patterns. The predicted tone response curve for each color channel and halftone is predicted using a binary printer model, wherein the “predicted tone response curve” provides a model based approximation of the actual response for each addressable pixel location in the spatial range. Also stored is an “average predicted tone response” by averaging the “predicted tone response curve” over the spatial range of the printer.

Abstract: A method and apparatus for processing an image are provided that can suppress blur edges at an edge portion of a character so that sharpness and quality of the image can be improved. The apparatus comprises an inside and outside edge discrimination portion for discriminating whether a target pixel to be processed belongs to an inside edge or to an outside edge, a threshold value generating portion for selecting a threshold value from plural threshold values for error diffusion process in accordance with an area discriminated by the inside and outside edge discrimination portion to output the selected threshold value and an error diffusion process portion for performing the error diffusion process for multilevel input data concerning the target pixel by utilizing the threshold value generated by the threshold value generating portion so as to produce output data whose gradation steps are reduced.

Abstract: A method and system are provided for characterizing performance of a printer across a plurality of halftone screens. A first non-uniformity profile is generated by measuring printer performance. Cross-position differences between the first non-uniformity profile and selected corresponding cross-positions of a second halftone screen are detected. A scaling factor is computed relating the detected differences. Printer performance with the second halftone screen is predicted by applying the scaling factor associated with the second halftone screen to the non-uniformity profile of the first halftone screen.