Abstract: Provided are a method, system, and program for generating threshold values in a dither matrix. A dither matrix of threshold values is generated.

Abstract: A method for dithering image data is provided. The method is suitable for representing A-bit grayscale values with a B-bit resolution, where A and B are positive integers and A>B. The main steps of the method include calculating 2A target grayscale values with decimals within an interval from 0 to (2B?1)*2A?B, and then representing the target grayscale values with the decimals through 2-dimensional dithering or 3-dimensional dithering.

Abstract: A system and method for halftoning for multi-pass rendering of an image in which different pixel locations are rendered in each pass which reduces the effects of inter-pass mis-registration errors. The method of halftoning includes restricting a substantial majority of the pixels turned on to render a tone to the minimum number of passes required to produce the tone. The halftoning method can include generating a stochastic halftone turn-on sequence and re-ordering the turn-on sequence. The halftoning method can also use error diffusion, adding a zero mean bias signal to either the image input pixels or the threshold values. The halftoning method is applicable to color or black and white rendering.

Abstract: A print system includes a computer and a printer. Image data having pseudo gradation with a dither pattern are printed by the printer. The computer divides the image data into predetermined areas, determines whether or not a dot arrangement pattern of image data in each of the areas matches a dither pattern that was used for generating the pseudo gradation, determines a representative value concerning a density of image data within the area if they match one another, and sends data related to the determined representative value to the printer. The printer obtains a representative value of each area from compressed data received from the computer and compares the obtained representative value with the dither pattern so as to reproduce a dot pattern.

Abstract: An image processing method processes image data to be output to an image forming apparatus that is capable of making a two-way recording to form an image on a recording medium by recording in a forward path and a return path of a scan by an ink-jet recording head. The image processing method includes a halftone process that is based on an inclined line-group keytone and maintains keytone continuity, including a dither process in which the inclined line-group keytone appears at a stage where the recording in the forward path is made.

Abstract: An image is generated by performing area coverage modulation to express a halftone color according to a gross area of dots displayed in a pixel of the image. The image is generated in such a manner that the halftone color is expressed with a selected one of dither patterns corresponding to respective predetermined densities, each of the densities being determined by the gross area of dots calculated in view of shapes of the dots.

Abstract: An image processing method for adding noise-like texture to the print through the manipulation of halftone screens. The method injects noise into halftone thresholds arrays rather than directly into the image. The method operates by creating a halftone threshold array of suitable size to support the desired noise characteristics. A textured pattern of a corresponding size is created having the desired noise characteristics and boundary transitions. The texture pattern is applied to the halftone threshold array by an amount determined by a noise amplitude control curve. The incoming contone image is then processed with the modified halftone screen.

Abstract: An image processor for converts input grayscale values into output grayscale values having two or more grayscales by dividing an input image into pixel groups each including pixels and applying a dither matrix to each pixel group a center of gravity position of the pixel group from the input grayscale value of each pixel included in the pixel group; the center of the dither matrix on the center of gravity position of the pixel group; and output the output grayscale values by corresponding the positioned dither matrix and the input grayscale value of each pixel included in the pixel group. By this, the center of the dither matrix is positioned on the center of gravity position of the pixel group. So dots are generated at the most appropriate positions to reproduce an input image faithfully.

Abstract: An image processing method comprises the steps of: determining dot arrangement in forming an image with dots on a recording medium; and forming the image on the recording medium by means of a dot formation device according to the dot arrangement, wherein dot arrangement data concerning each of dot formation positions on the recording medium is created from input image data, according to a dot model which is established with respect to each of the dot formation positions, the dot model being determined according to at least one of dot formation characteristics of the dot formation device and fixing characteristics of the recording medium, and including information relating to at least one of a dot shape, dot density, a dot position, and presence or absence of a satellite, of each dot formed on the recording medium.

Abstract: An image forming apparatus includes a storage unit configured to store a divisor matrix including at least two kinds of divisor values, and a changing unit configured to change M (M>N) gradation image data into N (N>3) gradation image data, wherein the changing unit is configured to divide a pixel value of a target pixel of the M gradation image data by a divisor value corresponding to a pixel position of the target pixel to change the M gradation image data into the N-gradation image data.

Abstract: A method and system for generating halftone tables, using a spot function, subdivides the pixels within the halftone cell of a halftone matrix into a plurality of sub-pixels, determines the value of the spot function corresponding to the position of each of the sub-pixels within the halftone matrix, repeats the subdividing and determining for all of the sub-pixels in the halftone matrix, ranks the values for the entire halftone matrix, normalizes the ranked values, generates a cumulative histogram based upon the normalized values, and stores the cumulative histogram as a halftone table.

Abstract: A method for compressing image data that are processed by a pseudo gradation process using a dither pattern is provided. The method includes the steps of dividing the image data into predetermined areas, determining whether or not a dot arrangement pattern of the image data in each area matches the dither pattern that was used in the pseudo gradation process, determining a representative value concerning density of the image data in the area if the dot arrangement pattern matches the dither pattern, and making compressed data by using the determined representative value.

Abstract: A printing apparatus divides printing elements of a printhead into blocks, time-divisionally drives the printing elements, and prints a halftone image on a printing medium in accordance with a result obtained by performing digital-halftoning for input multi-valued image data in each matrix of a predetermined size. The apparatus includes a scanner for reciprocally scanning the printhead, a conveyor for conveying the printing medium in a direction different from a scanning direction of the printhead, and a controller for printing a halftone image in each matrix. An arrayed direction of the printing elements is the convey direction of the conveyor. The controller sets a size of the block to be equal to or an integral multiple of a size of the matrix in the convey direction. The digital-halftoning increases the number of dots from a center of the matrix as a density expressed by the multi-valued image data increases.

Abstract: Pixels are grouped into groups of pixels, comprising a plurality of pixels each, and representative tone values are determined for each of a plurality of regions into which the groups of pixels are split. Decisions are made as to whether or not to output dots to the individual pixels in the group of pixels based on the multilevel halftoning resultant values obtained through performing multilevel halftoning on the representative tone values, to thereby output an image. The multilevel halftoning resultant values can accelerate the creation and transfer of data, enabling rapid outputting of images.

Abstract: The present invention is directed to a system and method for halftone screening. A system for halftone screening includes means adapted to receive image data having a desired number of tonal levels representative of a continuous tone image and means adapted to compress the received image data from a desired number of tonal levels to image data having a lesser number of tonal levels. The system further includes a memory including a look-up table, the look-up table including each of the lesser number of tonal levels and an array containing screen frequency data for each of the lesser number of tonal levels. The system still further includes means adapted for communicating the image data containing each of the lesser number of tonal levels to the look-up table, whereby corresponding screen frequency data is output therefrom.

Abstract: A threshold value matrix is used for converting a multi-level image data into a plural-level image data which represents a dot pattern by a smaller number of gradation levels than the multi-level image data, and comprises threshold values used for making a dot representation solely by a dot pattern while maintaining an identical keytone for all halftone levels.

Abstract: The number of pixels of a dot of a minimum size, a pattern frequency of an intermediate tone, the number of new dots of the minimum size at each dot percentage are determined. Then, thresholds in the threshold matrix are determined so that the optimum dot pattern at each dot percentage is obtained, and a threshold matrix is generated. A threshold matrix for C-separation is assigned to a separation for R that is complementary to C. A threshold matrix for M-separation is assigned to a separation for G that is complementary to M. A threshold matrix for Y-separation is assigned to a separation for B that is complementary to Y.

Abstract: An apparatus and method are provided to accelerate error diffusion for color halftoning for embedded applications. High performance is achieved by utilizing functional parallelism within the halftoning error diffusion process, including exploiting data parallelism in different color planes, reducing the number of memory accesses to the error buffer, accelerating the computation by using a parallel instruction set, and improving the throughput of the system by implementing pipelined architecture. A halftoning coprocessor architecture can implement the foregoing. The architecture can be optimized for high performance, low complexity and small footprint. The coprocessor can be incorporated into embedded systems to accelerate the performance of error diffusion halftoning therein.

Abstract: When the input value becomes close to the medium dot relative density value (Den_M), the large dot threshold value (Thre_L) and medium dot threshold value (Thre_M) become close to each other. It is possible to prevent output values from being converged to the particular medium-dot output value. When the input value becomes close to the small dot relative density value (Den_S), the medium dot threshold value (Thre_M) and the small dot relative density value (Den_S) become close to each other. It is possible to prevent output values from being converged to the particular small-dot output value.

Abstract: Successive frames or images of an input image that are presented to the output device are individually halftoned. A starting location within the input image for tiling one of one or more halftone techniques over the frame or image is determined. The starting location is then offset from the previously used starting location after a certain number of frames or images have been halftoned. Any halftoning technique may be used to halftone the frames or images. The halftoned frames or images are then viewed in a sequence in time.

Abstract: Image data processing methods, hard imaging devices, and articles of manufacture are described. According to one embodiment, an image data processing method includes accessing image data of an image and comprising a plurality of pixels, defining a plurality of subsets of the pixels, defining an overlapping region comprising image data of pixels located adjacent to a boundary intermediate one and an other of the subsets, independently processing the image data of the one and the other of the subsets individually comprising comparing the image data for respective ones of the pixels with a plurality of thresholds corresponding to respective ones of the pixels, and modulating the thresholds of the pixels of the overlapping region using a common modulation pattern for both the processing of the one and the other subsets.

Abstract: Techniques for generating dither masks are provided. A dither mask is generated by selecting a sequence of at least three original patterns comprising pixels of at least one of a first color and a second color. At least two patterns are interpolated to generate interpolated patterns in the sequence between the at least three original patterns. If a pattern having at least one specified characteristic exists in the sequence, the steps of interpolating between at least two patterns, and determining if a pattern having at least one specified characteristic exists in the sequence, are repeated. The interpolation is between at least one pattern from each side of the pattern having at least one specified characteristic in the sequence.

Abstract: A smoothing process is performed on image data to obtain improved image quality. Output image data is switched among image data subjected to smoothing, image data subjected to second bit conversion, and image data subjected to pseudo halftone representation process. In this manner, jaggies at edges can be smoothed even in multilevel image data subjected to image forming process such as screen processing. Smoothing for image data with degraded image quality due to, for example, lossy compression such as JPEG compression can also be achieved. Furthermore, degradation in image quality that occurs when a conventional smoothing process is applied to image data subjected to particular image processing can be avoided.

Abstract: An image processing system receives an input gradient number m, input image data I(x,y) whose input gradient number is m, and an output gradient number n and calculates output image data O(x,y) having an output gradient number of n on the basis of the following formula (1). O(x,y)=int[?+d(xd,yd)/(gmax+1)] ??(1) When ? is an integer, the output image data O(x,y) is calculated on the basis of a formula obtained by substituting the calculated ?? for ? in the above formula (1), whereas when ? is not an integer, the output image data O(x,y) is calculated on the basis of the above formula (1).

Abstract: An image processing method processes image data to be output to an image forming apparatus that is capable of making a two-way recording to form an image on a recording medium by recording in a forward path and a return path of a scan by an ink-jet recording head. The image processing method includes a halftone process that is based on an inclined line-group keytone and maintains keytone continuity, including a dither process in which the inclined line-group keytone appears at a stage where the recording in the forward path is made.

Abstract: A method and system are provided for processing digital multi-colour images for the reproduction thereof on a colour printing and/or copying system. Particularly, the printing and/or copying system is capable of complementary forming registered composite multi-colour images of coloured marking particles. This means that the separation images of coloured marking particles are formed contiguous to each other rather than in a superimposed relationship. The digital multi-colour images are processed such that during reproduction thereof any adverse effects on image quality caused by register errors in a predetermined direction are eliminated or at least limited. To accomplish this, a particular halftoning technique is used wherein with gradually increasing input density value of the image pixels, a linear growth pattern is generated in the predetermined direction by alternately adding image dots to both sides.

Abstract: In an apparatus for performing printing using a color ink-jet head having a plurality of ink-discharge-port strings corresponding to ink materials having different color tones, a high-quality image having excellent gradation can be recorded, while reducing the cost of the apparatus and increasing the data processing speed by reducing the capacity of a memory for storing dot arrangement patterns.

Abstract: A drawing instruction processor refers to a bit map line table that shows whether the bit arrays in the row unit are the same in the order of concentrations. The drawing instruction processor decides whether dither patterns to be used for the adjacent specified drawing ranges are the same, by referring to the BLT, and links the drawing ranges to which the same pattern can be applied. Based on this, the drawing processor carries out a batch writing using a dither pattern prepared in advance into the specified range in the page memory. The dither pattern to be used for the drawing is prepared by linking a plurality of the same basic patterns to have a length corresponding to the length of the word length. As a result of such an arrangement, it is possible to achieve a high-speed processing.

Abstract: A method for multi-level halftoning an input digital image to form an output digital image which includes a multi-level error diffusion halftoning process incorporating periodic dither signals whose amplitudes are adjusted as a function of the error-diffusion texture characteristics.

Abstract: The present invention relates to an image processing technique for improving dot dispersion in highlight areas and shadow areas in an error diffusion method. The image processing device of the invention has a plurality of types of error diffusion matrices with different diffusion ranges, and selects a matrix depending on the error that has occurred, which is then used to diffuse the error into peripheral pixels. Of the plurality of error diffusion matrices, the matrix having the widest diffusion range is a matrix that diffuses error with bias in the raster direction (specifically, a matrix having a directivity factor of 2.0 or higher).

Abstract: In a computer generation of a dither mask for conversion of a continuous-tone image into a halftone image, a pixel array having a size in accordance with the dither mask is partitioned into blocks. Initial pixel values are determined such that the occurrences of pixel values will be substantially uniform in the blocks. A pair of exchange target pixels are selected at random from the pixels in one of the blocks and function values of a predetermined evaluation function that indicates a characteristic of the pixel value configuration of the pixels in this block are computed for the two cases where pixel values are exchanged among the exchange target pixels and where not exchanged. These function values are compared to judge whether exchange should be performed.

Abstract: Techniques for securely displaying text on a display panel involve destroying spatial and temporal correlations in an otherwise uniform visual field. The techniques render the displayed text secure with respect to attempts to copy the text using a video capture device or still-picture camera. The techniques also render the displayed text unreadable to casual over-the-shoulder viewing by strangers outside of a certain narrow reading area.

Abstract: A four-time resolution refinement of 3D-dither algorithm is provided in this present invention. A 4×2 pixel-block is treated as an observed unit in this present invention, which includes two 2×2 pixel-blocks. In order to eliminate moving lines and dithered edges, the two least significant bits (LSBs) of the pixels are treated depending on cases. For the first 2×2 pixel-block, when 2-bit LSBs being 01 and 11, the pixel being assigned a carry is an upper-left, lower-right, lower-left, and upper-right sequence in a 2×2 pixel-block for four sequential frames. For the second 2×2 pixel-block, when 2-bit LSBs being 01 and 11, the pixel being assigned a carry is a lower-left, upper-right, upper-left, and lower-right sequence in a 2×2 pixel-block for four sequential frames. For both 2×2 pixel blocks, no pixel is treated for 2-bit LSBs being 00. For 2-bit LSBs being 10, the pixel row of the 4×2 block switches between the upper and the lower row for every frame.

Abstract: There is provided an image processing apparatus which enables high-speed processing with simplified multiplications and divisions even in the case of error diffusion comprised of a combination of processes of two or more colors. The image processing apparatus performs error diffusion on multivalued image data composed of a plurality of density components and outputs the result of the error diffusion. A plurality of error tables are stored in a storage device. One error table is selected from the plurality of error tables according to a density value of a first density component among the plurality of density components and a density value of at least one other density component when performing the error diffusion on the first density component. A CPU performs the error diffusion on the multivalued image data using the selected error table.

Abstract: An image forming apparatus includes an image forming device configured to form an output image using at least two or more image space frequencies and an image size acquisition device configured to recognize a size of the output image. A switching device is configured to select one of the at least two or more image frequencies for the output image according to the size of the output image recognized by the image size acquisition device and to switch the image forming device so as to form the output image using the one of two or more image frequencies.

Abstract: In an image processing apparatus which performs an error diffusion process to multivalued image data consisting of plural density components and outputs a result of the error diffusion process, the process result from a first error diffusion unit performing the error diffusion process based on a density value of a first density component included in the plural density components or the process result from a second error diffusion unit performing the error diffusion process based on the density value of the first density component and a density value of at least one density component included in other density components is selected according to a predetermined condition. Thus, even in an image process is performed to a larger number of gradations, a high-speed process can be achieved with simple structure, and the error diffusion process can be effectively performed to a shift of dot apply positions.

Abstract: There is generated a virtual tile set which virtually covers color planes of an original image without any clearance or overlap by combination of Penrose-type virtual tiles to be non-periodically provided on the planes. The respective tiles are subjected to raster conversion in accordance with predetermined gradation levels, thereby generating a raster image. Since the virtual tiles can be laid non-periodically, iteration of the same dot pattern on the raster image can be prevented.

Abstract: There is provided an image processing apparatus employing an error diffusion method capable of preventing a pseudo contour attributable to a delayed dot. The image processing apparatus receives an error diffused from a neighboring pixel and corrects a value (an input value of 0 to 1) of a pixel to be processed before it reduces a tone. Then a subtracter calculates an error associated with the tone reduction, which is diffused to a neighboring pixel. Herein, only for an input value of no less than 0.5 an inversion portion multiplies by ?1 an error from a neighboring pixel and an error to a neighboring pixel. Thus a dot can be free of delay to prevent a pseudo contour.

Abstract: A display system provides temporal stochastic dithering to image data for storage in a frame buffer for display. Stochastic dithering is used to reduce the size of the frame buffer and the complexity of the drive circuitry that is used to display an image in accordance with the image data. The bit depth of the frame buffer is reduced by spatially dithering image data for the image data before the image data is written into the frame buffer. Additionally, the displayed image is temporally dithered by using a different dither pattern for successive frames. Uncorrelated stochastic dither patterns are used to minimize detection of the dither patterns within the displayed image.

Abstract: A method and apparatus for dithering may provide filtering M bit data and performing a temporal/spatial compensation based on LSB of the filtered M bit data. The dithering may be performed on a selected frame. M-2 bits of the M bit data may be specified as a reference gray scale value resulting from the filtered M bit data. Temporal compensation may provide adding a weight of ‘0’ or ‘1’ to the reference gray scale value, for example M-2 bit data. Spatial compensation may include horizontal or vertical mirroring, and may be performed to represent whole gray scales without saturation.

Abstract: Selective edge softening and selective edge dithering is introduced into an image representation to improve local control where halo problems are expected. Selective areas of dilation are isolated and separately dithered or halftoned, the result of which is then swapped back into or substituted for the stored original image. In this manner misregistration and color plane-to-plane interactions can be compensated for in plural image forming station architecture systems. The same technique is also valuable in monochrome systems as an aid to overcoming edge displacement and slow toner problems when the selective edge softening is selectively applied to edges which are in particular perpendicular to the fast scan direction.

Abstract: A threshold array having an array of thresholds for reproducing a gradation with a dot pattern as a clustered pattern of dots each made up of one or more blackening pixels is corrected. At least one non-contact point candidate position to be turned into a non-contact point is determined among contact points of the dots. Then, at least one contact point candidate position to be turned into a contact point is determined among non-contact points of the dots at the given gradation. Thereafter, the threshold array is corrected by switching around a threshold for the non-contact point candidate position and a threshold for the contact point candidate position, whereby the layout of contact points of the dots can be corrected.

Abstract: A method that quickly corrects an image without inputting more than a required number of rendering instructions. Input image that contains a plurality of objects, and rendering command statements that specify rendering of the plurality of objects are input and analyzed in order to identify the types of objects. If a specific type of object is identified through the identification, a rendering command statement that specifies rendering of the specific type of object is re-input in order to correct the specific type of object. If the specific type of object is not identified through the identification, a rendering command statement needed for execution of image correction is not re-input.

Abstract: A printer that stores a minimal number of unadjusted stochastic threshold arrays in non-volatile memory, in which the unadjusted threshold arrays are used to generate adjusted threshold arrays at run time by use of special parameterized transfer functions. The unadjusted array for a particular color is stored in the printer's ROM and preferably is stored in a packed configuration to save memory space. The parameterized transfer functions are used to convert the unadjusted threshold data into adjusted threshold data for each color and type of print media. These parameterized transfer functions are stored in the printer's non-volatile memory, and take up very little memory space. In a preferred embodiment, the unadjusted threshold array comprises a 128 row by 128 column sized array, and each element of this array comprises a 10-bit number. When a parameterized transfer function is applied to this unadjusted array, the resulting numeric values for the adjusted array elements are produced as 8-bit numeric values.

Abstract: A method of displaying an image with a display device includes receiving a first set of image data for a first image. A first sub-frame and a second sub-frame corresponding to the first set of image data are generated. A bit-depth of the first and the second sub-frames is reduced based on a first set of quantization equations, thereby generating a first dithered sub-frame and a second dithered sub-frame. The method includes alternating between displaying the first dithered sub-frame in a first position and displaying the second dithered sub-frame in a second position spatially offset from the first position.

Abstract: The invention is related to a new kind of pre-processing for plasma display panel control. The plasma display technology has the drawback of a reduced grey scale portrayal. This is due to the fact that contrarily to CRTs where luminance is approximately quadratic to the applied cathode voltage, luminance is linear to the number of discharge pulses in PDPs. Therefore, an approximately quadratic degamma function has to be applied to the input video signal components R,G,B before sub-field coding can be done. Truncation to 8-bit video data is required, so that the effect of the degamma function cannot be fully maintained. Especially in the region of small video levels, where the eye sensitivity is high, the grey scale portrayal is poor. According to the invention it is proposed to use a new kind of dithering, adapted to the PDP specialities to improve the grey scale portrayal. These adaptation includes three dithering specialities which can be used singly or in combination. These are: cell-based dithering, i.

Abstract: A method, apparatus and article of manufacture for modifying printing based upon direct on-the-fly media characteristic parameters is disclosed. The present invention on-the-fly directly measures a media characteristic parameter and performs real-time print modification in response thereto. The measured characteristic parameters include paper texture and composition, as well as adhesion and penetration of print. The modification of print in response to these measured parameters may allow a customer to maintain observed print quality with lower-cost materials. Adjustments may include the addition of coating, hot rolling, or adjustment of toner concentration. Measured parameters may include mottle, paper texture, and bleed through.

Abstract: A halftone threshold matrix includes a plurality of submatrices, wherein a first group of the plurality of submatrices has a line screen frequency different from a second group of the plurality of submatrices. The halftone method and apparatus removes the restriction that at most one pel is turned on per basic cell for the next constant input level and allows the pels in some basic cells to be turned on much sooner that the corresponding positions in other basic cells. This creates a dominant low frequency line screen simultaneously with the higher frequency line screen of the other basic cells. The present invention also allows the basic cells inside the threshold matrix to have different shapes and sizes. Thus, the cells participating in the low frequency screen could be larger than the cells generating the higher frequency screen. For example, the low frequency screen's pleasing patterns can distract the eye from noticing less pleasing patterns in the high frequency grid and vice versa.

Abstract: An image processing apparatus providing a halftoning process such as error diffusion prevents an image contour distortion, as follows: data in an image to be processed is used to partially extend the image to be processed. Then error diffusion or the like is employed to provide a halftoning process. The extension is removed to obtain image data. A dot generation delay can be prevented that would otherwise be introduced such as when an extension-free image is halftoned.

Abstract: An image processing apparatus processes image data which is obtained by reading an halftone dot image. In the image processing apparatus, the image data is separated into the image data corresponding to halftone dots which form the halftone dot image and other image data. On the image data corresponding the halftone dots, the smoothing process is performed, and on the other image data, the edge enhancement is performed. Both of image data are synthesized and outputted. Since only the separated image data corresponding to halftone dots are smoothed out, it is possible to suppress creation of a moiré due to the halftone dot image which is an aggregation of the halftone dots, without influencing the smoothing processing upon the character portion in the vicinity of the halftone dots. On the other hand, since the other image data are edge-enhanced, the character portion, a line and the like show sharp and legible.