Abstract: Systems and methods are provided for processing at least one document comprising color data. Color data in the document in a first color space is inspected to determine if a color space conversion operation for a portion of the color data is specified using a color space dictionary or a transformation matrix, wherein the color space conversion operation converts the color data from the first color space to an intermediate standard color space. An input profile corresponding to the color conversion operation is generated, wherein the input profile comprises information to convert color data from the first color space to the intermediate standard color space; and color space conversion operations are performed on the color data using the generated input profile to convert the color data from the first color space to the intermediate standard color space.

Abstract: An image forming system includes an image transmitting apparatus which transmits generated image data to a designated transmission destination, and an image receiving apparatus which executes processing for the received image data. The image transmitting apparatus includes a designation unit which accepts designation of an image receiving apparatus serving as a transmission destination, and designation of a transmission mode which specifies the contents of processing in the image receiving apparatus, an acquisition unit which acquires transmission destination information representing the operating state of the image receiving apparatus by communication with the image receiving apparatus, a generation unit which generates image data to be processed in the image receiving apparatus on the basis of the designated transmission mode and acquired transmission destination information, and a transmitting unit which transmits the transmission mode and image data to the image receiving apparatus.

Abstract: A method and a printing implementing the method for dynamic printer performance tuning. The method includes the steps of processing a page to be printed by a printer description language interpreter to generate a Display List, selecting tuning parameters from the Display List data, analyzing the tuning parameters by a Bayesian analyzer to obtain a score for each tuning parameter, and based on the score of each tuning parameter, adjusting rendering settings of the tuning parameters for printing the page. The steps of training the Bayesian analyzer includes creating a set of training pages, rendering each page to determine best performance settings for each tuning parameter, grouping the pages based on tuning parameter settings, generating Display List data of each page, rendering the training pages in each group to compile training data that are saved for future printing jobs.

Abstract: An image processing apparatus includes: a quadrangular or polygonal area setting unit that sets a quadrangular or polygonal area that surrounds a group of pixels that has predetermined characteristics for image data; a background setting unit that measures frequency distribution of tone values outside the quadrangular or polygonal area, measures a brightest tone value B in a margin range, which is a range of tone values in which the image data is distributed significantly, measures a most frequent value M in the margin range, and sets a background range, which is a range that includes the most frequent value M as a median point and further includes the brightest tone value B as one end of the range; a black edge statistics unit that measures frequency distribution of tone values of black edge inside the quadrangular or polygonal area and measures a greatest brightness value b in a black edge range, which is a range of tone values in which the black edge is distributed significantly.

Abstract: Image data including color separation data and gloss data of an image is input. The color separation data is quantized to generate a color signal. The gloss data of the image is quantized on the basis of the color signal and gloss data related to a recording medium, a color material, and a gloss control material to generate a gloss signal. An image is formed on the recording medium on the basis of the color signal and the gloss signal using the color material and the gloss control material.

Abstract: A printing apparatus and method for processing data in the printing apparatus includes estimating a printing time by adding an intermediate data generation time and a rendering time, determining whether the estimated printing time of each page keeps up with a timing at which an image needs to be formed on a conveyed sheet for each page. If it is determined that the estimated printing time does not keep up with the timing at which the image needs to be formed, further determining whether an idle time is present by comparing the intermediate data generation time and the rendering time. If it is discriminated that the idle time is present, the changing an optimization level for determining whether to perform processing on a particular object in the document image data during rendering, or to perform the processing during intermediate data generation.

Abstract: A method for defining a gloss effect in a printed document includes printing a document region with first and second colorant combinations. The first colorant combination defines a first colorant stack height and said second colorant combination defines a second colorant stack height that differs from the first colorant stack height. As such, the document region has a first appearance when viewed straight-on and a second appearance when viewed at an angle. In one example, the first colorant combination is black (K) colorant that results in a one-level stack height and the second colorant combination is cyan, magenta, and yellow (CMY) colorants that result in a three-level stack height. In another example, the second colorant combination can be cyan, magenta, yellow and black (CMYK) colorants that define a four-level stack height.

Abstract: An image processing apparatus including a specific image detection unit detecting an area including at least a part of a specific image in an input image, a representative color calculation unit calculating a representative color of the specific image on the basis of pixels belonging to the area detected by the specific image detection unit, plural correction curve acquisition units which acquire plural correction curves resulting in gradation correction for every element color on the basis of the gradation value for every element color constituting the representative color after correction, and plural correction units which correct the gradation value for every element color in each pixel constituting the input image based on the obtained plural correction curves.

Abstract: A system and methods for performing UCR/GCR (Undercolor Removal/Gray Color Replacement) in a digital printer is provided. The system and method includes maximizing the linearity of a color mapping function mapping a device independent color to a device dependent color through linear filtering and performing color projection to ensure color accuracy. The system and methods reduces graininess of printed color images having flesh-tones by also including a K reduction step.

Abstract: Engine response curves (RCs) can be used for streak compensation for printed documents. A feedback control paradigm can be included to effect RC compensation. Singular Value Decomposition (SVD) can be used to represent each RC in the collection of spatial RC data as a linear combination of basis vectors. RCs are approximated by selecting the first few basis vectors, the approximation aiding in noise rejection and reducing computation in the controller by reducing dimensionality of the RC data from gray levels to the number of SVD bases selected. An optimal subset of RCs is selectable from the set of approximated RCs by clustering the SVD weights, the clustered SVD weights producing TRCs that span all engine response RCs generated by a printer. Compensation RCs are constructible using reduced number of bases and clustered SVD weights.

Abstract: An image generating device comprises an acquisition unit which acquires an image drawing instruction for drawing an elliptical radial gradation from accepted target data, an extraction unit which extracts elliptical shape parameters and gradation pattern parameters from the acquired image drawing instruction, a transformation matrix generating unit which generates a transformation matrix for transforming an elliptical shape specified by the elliptical shape parameters into a perfect circular shape based on the elliptical shape parameters, an inverse matrix calculating unit which calculates an inverse matrix of the transformation matrix, a transformation unit which transforms the gradation pattern parameters using the transformation matrix, a drawing unit which draws a gradation for the perfect circular shape based on the transformed gradation pattern parameters, and a gradation generating unit which generates the elliptical radial gradation by inversely transforming the perfect circular shape (including the g

Abstract: An image generating device, for generating an image including a gradation (in which a color value specifying color changes from the center of the gradation through annular areas) according to an image drawing instruction, comprises an extraction unit that extracts gradation pattern parameters specifying a gradation pattern of the gradation from the image drawing instruction, an area determination unit that determines the annular areas, each having a prescribed width, to be drawn in one color with a uniform color value, based on the gradation pattern parameters extracted by the extraction unit, and a drawing unit that draws the annular areas such that each annular area is drawn in one color and the colors in annular areas are different from each other.

Abstract: A method and system for controlling the darkness level of image data to assist in output matching between dissimilar rendering devices. Image source information from a source file can be interpreted by a rendering decomposer in order to generate halftone source image data. The decomposition of the image can be repeated in response to a request by an operator for an additional darkening level via a user input file. The additional layers can be shifted in an opposing direction and then a clockwise direction from the original position until the additional darkening level is attained. The required darkening level can be stored in a storage unit or memory so that the required darkening level can be later triggered by a source document name to employ the same darkening approach. The darkening level can be selected from an array of darkening levels to assist in output matching without major modifications to the utilized rendering device(s).

Abstract: A method for using a processor to process image data received from an image data source in preparation for multipass printing, comprising multitoning the image data to produce a multitoned image, using the multitone level of a pixel in the multitoned image to select a plane of a print mask, using the location of the pixel in the multitoned image to select a cell of output pixels in the selected plane of the print mask, and copying the selected cell of output pixels to corresponding locations within a print buffer.

Abstract: An image processing apparatus includes a computation unit that determines an interpolation process starting point and gradient on the basis of a change point at which a difference between pixel values of adjacent pixels of an image signal is greater than zero and is less than or equal to a predetermined threshold value, wherein a position of a pixel scanned earlier or later than the change point by substantially one-half a continuous width of pixels having an identical grayscale value is set as the starting point and the gradient is determined based on a difference between pixel values before and after the change point and the continuous width, and a conversion unit that converts pixel values of the image signal on the basis of the determined starting point and gradient so that a grayscale change from the interpolation process starting point in the image signal corresponds to the gradient.

Abstract: A technique for performing high-quality cluster type FM halftone image output without “anisotropy” or “sweep out texture” phenomenon is provided. An error diffused to a current pixel position and a random number RND are added by an adder to multi-level pixel data as a subject of binarization, and supplied as pixel data Pxy to a selector. The selector compares the pixel data Pxy with thresholds, and supplies the pixel data Pxy to one of a highlight portion processor, a dark portion processor and an intermediate portion processor. The highlight and dark portion processors refer to already-binarized results within a range determined in accordance with the value of the input pixel data Pxy, and determine a binarization result Qxy. The intermediate portion processor compares a threshold, which monotonously increases in accordance with the value of the pixel data Pxy, with the pixel data Pxy, thereby determines the binarization result Qxy.

Abstract: There is provided an image printer having a display unit, in which a predetermined image can be set as a background picture of the display unit. The image printer includes an image processing unit processing an image selected by a user in accordance with a predetermined image processing technique so as to set the selected image as a background picture of the display unit; and a setting unit setting the processed image as the background picture of the display unit, wherein the display unit displays the processed image.

Abstract: In a matrix area, a plurality of linear areas each of which extends in a tilt direction tilted relatively to row and column directions are arranged in a direction perpendicular to the tilt direction without spaces, and the plurality of linear areas are alternatively assigned to first and second element groups along an arrangement direction. One element is specified in each element group and subsequently process of specifying an element farthest from specified elements, is repeated to acquire a turn-on order of dots with increase in gray level in one grayscale range and a turn-off order of dots with decrease in gray level in the remaining grayscale range, and a threshold value of each element is determined according to these orders. Thus, generated is a threshold matrix capable of reducing graininess in a halftone image with directionality in the tilt direction, and improving the reproduction of thin lines and characters.

Abstract: An information processing apparatus processes, for each pixel, multivalued image data for a unit area of a recording medium, so as to form an image on the unit area with a plurality of relative movements between a recording head and the recording medium. The apparatus has a selector that selects a first processing mode for dividing the multivalued image data into a plurality of pieces of multivalued image data corresponding to the plurality of relative movements, and then quantizing each of the plurality of pieces of multivalued image data, or a second processing mode for quantizing the multivalued image data into quantized image data, and then dividing the quantized image data into a plurality of pieces of quantized image data corresponding to the plurality of relative movements. The selector selects the processing mode based on a content (attribute, grayscale, color, etc.) of the multivalued image data.

Abstract: Machine-enabled methods of, and system, and processor readable media, embodiments for, tone quantization error diffusion comprising a first stage process and a second stage process. where pre-calibrated index tables may be applied by which quantized pixels may be expressed according to halftones.

Abstract: An image processing device includes a multi-layer data acquiring part configured to acquire multi-layer data having a required-formation-amount-related value representing a value relating to a formation amount required to form an image, and an expanding part configured to expand, based on a correspondence relationship for expansion, the acquired multi-layer data into multiple sets of single-layer data. The correspondence relationship for expansion has a correspondence relationship between the required-formation-amount-related value in each of the sets of single-layer data and the required-formation-amount-related value in the multi-layer data. The required-formation-amount-related value in the multi-layer data is image data that exceeds a maximum-formation-amount-related value representing a value relating to a maximum formation amount of a color value of the single-layer data with which an image can be printed in a single printing process.

Abstract: An object of the present invention is to provide an image processor capable of generating an image from which a user-designated color component has been removed and performing a color/monochrome determination correctly. In order to complete the task, an image processor according to the present invention comprises a removal unit that removes a removal color part from a read image, and a determination unit that determines whether the read image from which the removal color part has been removed by the removal unit is a monochrome image or a color image.

Abstract: An error diffusion process section performs an error diffusion process on a pixel value of each of processing object pixels and outputs the processed pixel value to an output selection section. A blue noise mask process performs a blue noise mask process on a pixel value of each of processing object pixels and outputs the processed pixel value to the output selection section. The output selection section selects and outputs the pixel value outputted from the error diffusion process section when a segmentation class signal indicates a character (text) area or a halftone dot area, namely an edge area, and selects and outputs the pixel value outputted from the blue noise mask process section when a segmentation class signal indicates an area other than the character area or the halftone dot area, namely non-edge area.

Abstract: In performing multi-pass printing by using a printhead having a plurality of nozzles, a print data setting unit sets a printing amount for each nozzle for each main scan of the printhead based on a print data setting LUT. This print data setting LUT reflects the information of the number of passes and the number of nozzles to be used which are arbitrarily set. A halftoning unit generates a dot pattern as a formation target by performing binarization processing for the print amounts set in this manner.

Abstract: To enable the printing in which it is difficult for the dot to stand out and it is difficult for the gradation sequence properties to be degraded. Therefore, among plural dots each having a different size, the binary processing is carried out by using the same first dot arrangement pattern in regard to the large and medium-sized dots and the binary processing is carried out by using a dot arrangement pattern different from the first dot arrangement pattern in regard to the small-sized dots.

Abstract: An image processing apparatus performs a first edge determination to determine whether each pixel is an edge of a black character or a thin black line based on a pixel signal of a predetermined color in each pixel included in multi-valued image data. The image processing apparatus determines whether to achromatize a pixel signal of each pixel included in the multi-valued image data based on a result of the first edge determination, and achromatizes a pixel determined to be achromatized. The image processing apparatus performs a second edge determination for determining whether each pixel is an edge based on a pixel signal of a color different from the predetermined color in each pixel included in the multi-valued image data. The image processing apparatus corrects the multi-valued image data based on a result of the second edge determination after completing achromatization of the pixel determined to be achromatized.

Abstract: An image processing apparatus, an image processing method, and a program thereof, and a display device are provided, in which reproduction of a secret image from one dispersed image is difficult. A secret image and a reverse image included in at least two types of images are in a relationship of forming image data of an image not correlated with the secret image when luminance values of image data respectively are added pixel by pixel.

Abstract: The present invention provides a method and system for determining near-duplicate images. The method and system includes performing a Fourier-Mellin transform on each of a plurality of images. For each image of the plurality of images, the method and system includes generating a signature based on the Fourier-Mellin transform. The method and system includes comparing the signature of at least one of the images to at least one of the signatures of the other plurality of images and determining any near duplicate images based on the comparing of the signatures.

Abstract: Quantizing means generates a quantized density and a quantization error component for a target pixel in a plurality of pixels. A subtracter calculates, for the target pixel, a quantization error correction component by subtracting the density of the target pixel contained in preliminary ejection data from the quantization error component output from the quantizing means. An allocator allocates the quantization error correction component calculated by the subtracter to a plurality of the pixels around the target pixel. The quantizing means outputs the quantized density and the quantization error component of the target pixel by performing an addition using the density of the target pixel contained in the image data, the density of the target pixel contained in the preliminary ejection data, and the accumulated diffused error component assigned to the target pixel by the allocator when other pixels are quantized.

Abstract: An image forming apparatus includes a resolution conversion unit that integrates n pixels that are contiguous in the sub-scanning direction, and that determines an average value of pixel values of the n pixels as a pixel value of integrated pixels, a quantization unit that quantizes the pixel value of the integrated pixels to N levels, an image analysis unit that performs first determination processing for determining whether the difference between the pixel values of the n input pixels exceeds a threshold value set in advance, and second determination processing for determining whether a direction in which the pixel values of the n input pixels becomes greater is a forward direction of the sub-scanning direction or an opposite direction, and a pixel selection unit that determines n output pixels, based on the results, from a quantization result of the integrated pixels.

Abstract: The present invention aims to prevent a problem that an image on a document sheet is erased due to misdetection of a line-shaped noise. A copy machine 1 compares RGB values of a target pixel with averaged RGB values (Step S103). If only one of the RGB values has a difference that is greater than a prescribed value Ref2 (Step S103: YES), the copy machine 1 extracts the target pixel as a line-shaped noise pixel, and moves to a line-shaped noise correction (Step S108) while holding the address of the target pixel in a line-shaped noise address storing area 49b. If two of the RGB values have differences (Step S103: NO, Step S104: YES) and a difference between these two of the RGB values is no greater than a prescribed value Ref3 (Step S105: YES), the copy machine 1 extracts the target pixel as a line-shaped noise pixel, and moves to the line-shaped noise correction (Step S108) while holding the address of the target pixel in the line-shaped noise address storing area 49b.

Abstract: A color conversion device converts an input value to an output value in order to form an image on a recording medium using an achromatic ink and a chromatic ink. The color conversion device include a first color converting unit, a second color converting unit, an adjustment value setting unit, and an output value acquiring unit. The first color converting unit converts the input value to first color data including a first chromatic component value. The second color converting unit converts the input value to second color data including a second chromatic component value and a first achromatic component value. The adjustment value setting unit sets an adjustment value based on a type of the recording medium. The output value acquiring unit acquires the output value by weighting the first color data and the second color data according to the adjustment value.

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 signal processing device includes a memory in which a color correction data is stored. The memory stores a first color correction data having the same number of bits as an input image data and a second color correction data having fewer number of bits than the input image data. The number of color correction data corresponding to a low gray-scale range increases and the number of color correction data corresponding to a high gray-scale range decreases by the same amount that the number of the color correction data corresponding to the low gray-scale range increased. Thus, a color characteristic corresponding to the low gray-scale range may be improved without changing the total number of color correction data.

Abstract: A device and method for use with an image recording device. The device having a background target and a first surface including the background target recessed therein. The device further including a substrate stabilizer configured to move a substrate having an image printed therein in closer proximity to the background target and below the first surface when activated.

Abstract: What is disclosed is a novel system and method for adjusting the gray balance of a multifunction color marking device in order to change the device's neutral behavior to a desired level of acceptability. The gray balance aim curve is specified by: L*, L*(aim), a*(aim) and b*(aim), where L*(aim)=f1(L*), a*(aim)=f2(L*), and b*(aim)=f3(L*). After receiving the user-modified gray balance aim curve, the target color device constructs a 3-D N×N×N L*a*b* to L*a*b* pre-LUT to reflect the neutral aim change by transforming a neutral axis input of L*, a*=0 and b*=0 to L*(aim), a*(aim) and b*(aim). Colors further away from the neutral axis are shifted by a lesser amount. The pre-LUT is then concatenated with the current color LUT to produce an updated color LUT which is applied to the device to achieve the desired neutral behavior. The gray balance aim curve can also be based upon a pre-determined user preference.

Abstract: An image compensating method. First, multiple scanning lines are used to scan a document and a longitudinal black and white pattern, in order to produce the actual gray level value for multiple pixels with respect to each of the scanning lines and the document, as well as a correctional gray level value for complete black and a correctional gray level value for complete white with respect to the longitudinal black and white pattern. Then, the compensational gray level value with respect to the actual gray level value for each of the pixels is obtained according to the correctional gray level value for complete black, the correctional gray level value for complete white, the theoretical gray level value for complete black, the theoretical gray level value for complete white, and the actual gray level value for each of the pixels. Then, the procedure is complete.

Abstract: A method is employed that represents patterns using a super resolution encoding method that distributes the code value among adjacent pixels. One or more blocks are created, wherein each block is comprised of a plurality of bits, the height of the block is equal to the width of the block. One or more supercells are created by merging at least two adjacent blocks. One or more patterns are defined, wherein each pattern is defined by selecting one or more bits to be one of filled or unfilled within each supercell. Each of the one or more patterns is associated with an SRE code, the SRE code is related to the number and location of bits that are filled within the pattern. A pattern is defined with a plurality of patterns, each pattern is included in the one or more supercells.

Abstract: An image forming method is disclosed in which an image is formed on commercial printing paper using a high penetration pigmented ink by performing image processing which makes use of dot patterns corresponding to an output halftone level.

Abstract: The image processor processes each pixel of a halftone image by sequentially setting each pixel as a target pixel. A converting unit converts a pixel density of the target pixel into a first output value. An error data calculation unit calculates error data of the target pixel. The error data corresponds to a difference between the first output value and the pixel density. A compression unit irreversibly compresses the error data of the target pixel. Partial data of the pixel density is lost from the error data when irreversibly compressing the error data. An error buffer stores the compressed error data of the target pixel and a plurality of sets of compressed error data for a plurality of processed pixels. A decompression unit reads and decompresses a plurality of sets of compressed error data for a plurality of peripheral pixels with respect to a next target pixel from the error buffer.

Abstract: What is disclosed is a novel system and method for minimizing dot visibility in color marking devices capable of dot-on-dot printing. The present method achieves minimum dot visibility for a given dispersed-dot screen by performing a CMYK to CMYKRGB conversion which uses less visible dots as much as possible before more visible dots are introduced. The output color dot coverages are calculated sequentially to minimize the coverage of more visible dots in a decreasing order of brightness. Resulting images have noticeably reduced halftone graininess, particularly in the mid to darker tone areas. The present method is also computationally efficient.

Abstract: Methods, systems, and apparatus, including computer program products, for reducing artifacts in a color sequential display system. A frame of a digital image is displayed by receiving frame data, determining dither patterns, applying the dither patterns to the data, and displaying the dithered data. Each pixel of a frame of a digital image is displayed by receiving pixel data, grouping the pixel data for the color channels of the image into a plurality of sub-groups of pixel data; and displaying the pixel according to a sequence that separates each pair of sub-groups for a color channel by a sub-group for another color channel. Modified pixel data can be generated by replacing parent bits in the pixel data with corresponding pluralities of divided child bits, where all the child bits for a given parent bit have a divided weight that adds up to the parent bit's weight.

Abstract: An image processing method for forming a color conversion table to convert plural input colors into output colors, the method including the steps of: extracting color values of plural gray scales wherein in input and output characteristic data, a signal value of one color is variable and signal values of other colors are fixed; creating a model with which difference values between input and output color values are outputted by inputting the extracted color values; and estimating the output color values corresponding to the input color values to create the color conversion table to convert plural input colors into output colors, after shifting the color values by adding or subtracting the difference values which are obtained by inputting the color values into the model with respect to every output color values.

Abstract: To improve a method for making an overprint prediction to that extent, that the method allows more reliable overprint predictions with a reduced effort, the invention proposes a method for making the overprint prediction for a color combination, in which method a printing substrate and at least two printing colors and one gradation of hue values per printing color including the full tone as well as color combinations are predefined as data of the hue value of the n printing colors, wherein first of all individual color predictions comprising three transmittance components and the associated transmittance spectra for the respective hue value are determined for each of the n printing colors, wherein for an intended color combination up to (3 to the power of n) combinations of the transmittance components and the associated combined transmittance spectra are determined, and an overall reflectance spectrum of an overprint is predicted on the basis of the determined transmittance components with their transmittanc

Abstract: An image recording apparatus includes: a recording head having plural recording elements; a characteristics information acquisition device; a correction calculation device which corrects image data using recording point positional deviation information within acquired characteristics information, and generates image data suppressing a non-uniformity streak in an output image; a nearest recording point specifying device specifying, when image density is outside an output image density range, a second recording element concerning a recording position nearest to a recording position of a first recording element corresponding to first image data outside the output image density range; a sum density calculation device calculating sum density of the first image data and second image data; an image data modification device which preserves the calculated slim density; and a drive control device controlling driving of the recording head in accordance with the corrected image data and modified image data.

Abstract: A device for creating print data utilized by a printer is disclosed. The print data includes a coordinate at which a dot is to be formed on a print medium by the printer. The print data creating device is provided with a first device and a second device. The first device chooses a first coordinate from bit-mapped data. The bit-mapped data includes a plurality of combinations of the first coordinate and color information. The first device chooses the first coordinate based on the color information being combined with the first coordinate. The second device creates the print data by converting the first coordinate chosen by the first device into at least two second coordinates which are randomly chosen from at least three second coordinates located in the neighborhood of the first coordinate.

Abstract: What is disclosed is a system and method for efficiently and accurately estimating the complete TRC for a color marking device equipped with a multi-center cluster halftone screen which has a similar halftone tiling geometry and a similar growth specified by a corresponding single-center cluster halftone screen. The present method introduces a cluster-based printer model which establishes a relationship between a color output of a single-center cluster halftone screen and a color output of a multi-center cluster halftone screen. The present cluster-based printer model determines the complete TRC for the multi-center cluster halftone screen using the measurements for the single-center cluster halftone screen. Results of halftone dot linearization with different printing devices demonstrates that high accuracy can be achieved using the reduced measurements from the single-center cluster halftone screen.

Abstract: Halftoning is performed on a source image. The halftoning includes error diffusion processing of one separation based on error diffusion processing of another separation. The error diffusion processing includes determining a rendered pixel value for the one separation by applying a quantization function for a given pixel. The quantization function is based on both a modified input determined as a function of an error value of a pre-rendered pixel for the one separation and an error value determined as a function of rendered pixel values for the another separation. A rendered image is output, which includes the same plural color separations. The output rendered image is populated with, for the one separation, a rendered pixel value based on the application of the quantization function.

Abstract: A method for correcting gray balance of a printing process includes imaging printing forms assigned to color separations with a test form, printing a printing material using the printing forms in a printing press and calorimetrically measuring the test form printed onto the printing material. It is undesirably possible to produce a new color error in other tonal value ranges due to changing the layer thickness of a process ink to correct the gray balance. In order to perform a gray balance correction without disruptive secondary effects, a test form is imaged with colored gray areas, after their colorimetric measurement, at least two of the colored gray areas are selected and, based on their color values, a corrected tonal value of a non-black chromatic process ink is determined, and this corrected tonal value is recorded as a corrected set point of the process ink for imaging following printing forms.

Abstract: A method for controlling a tone reproduction curve of an image printing system includes generating an actual printed image tone reproduction curve using printed image data from a printed image sensor; determining a set of adjusted contone values by comparing the actual printed image tone reproduction curve with a target printed image tone reproduction curve, where the adjusted contone values being representative of the print contone values at which target color density data of the printed image is achieved in the image printing system; and determining adjusted image transfer surface reflectance data to update a target image transfer surface tone reproduction curve, where the adjusted image transfer surface reflectance data being obtained by interpolating the target image transfer surface tone reproduction curve at the adjusted contone values; and controlling subsequent toner image data to achieve the updated target image transfer surface tone reproduction curve.