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: Selecting a corresponding procedure of dithering according to a general pattern of gray levels of sub-pixels of each color of an input image. This will enable the input image to be displayed on a display with a lower bit depth.

Abstract: Setting of growing directions of dots in a dither matrix is facilitated. During defining of the growing directions of the dots corresponding to cells in the dither matrix, a target cell in the dither matrix is defined. When the growing directions of the dots in cells located within a range of one cell from the target cell are not set, the target cell is set as a reference point. When the growing direction of the dot in the cell located at the immediate left or the immediate right of the target cell is set, the growing direction of the dot in the target cell is set based on setting states of the growing directions of the dots in the cells located at the immediate left and the immediate right of the target cell and the reference point.

Abstract: An image processing apparatus includes an input section and a binarizing section. The input section inputs multilevel image data. The binarizing section binarizes multilevel image data to generate output image data representing halftone dots each having a hollow-structure. The binarizing section enlarges the halftone dots in a predetermined direction preferentially in accordance with the input multilevel image data.

Abstract: A duplex simultaneous reading apparatus having an image reading unit for simultaneously reading a first surface and a second surface of a document, the duplex simultaneous reading apparatus includes: a detection unit for detecting any specified pattern image from image data read by the image reading unit; and a selection unit for selectively inputting the read image data of the first surface of the document and the read image data of the second surface to the detection unit in block units, wherein the detection unit detects the specified pattern image in the first surface or the second surface of the document, from the block-unit image data inputted by the selection unit.

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 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: When rotation processing is performed on an image obtained by screen processing, screen growth pattern changes and image quality changes. The image subjected to the screen processing is multi-value encoded by use of information of a dither matrix used for the screen processing, and a screen image is restored from the multi-value code after the rotation of the multi-value encoded image.

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: Whether or not a density of black is a predetermined value or more is judged, and when it is judged to be the predetermined value or more, a resolution characteristic is changed to an improved resolution characteristic compared to the resolution characteristic used in a case in which a judgment result shows a value under the predetermined value. When the density of black is deeper, the resolution characteristic is improved, and therefore black is prevented from becoming in a so-called void state. Accordingly, the color close to black such as four-color black can be stably and excellently formed. In addition, when the density of black is the value under the predetermined value, the resolution characteristic lower than this value is used, and therefore dots can be stably formed and an excellent gradation property can be achieved.

Abstract: A density detector detects a first density of a first pattern and a second density of a second pattern from a density-correction determination patch. A density-correction-value calculator calculates a density correction value from the first and the second densities. A noise-occurrence determination unit determines whether a target pixel is a noise generating pixel that causes a change of a local density due to a change in a relation with a nearby pixel. A density correction processor performs a density correction process on the target pixel by adding or subtracting the density correction value to or from the target pixel or the nearby pixel.

Abstract: An image forming apparatus comprises an image data generating unit configured to convert a tone of an input value which indicates a density of a pixel by using a predetermined dither matrix and generate image data. The image forming apparatus further comprises a drive source and a gear configured to transmit a drive force from the drive source to an image carrier. The dither matrix includes a plurality of sub-matrixes arranged in a predetermined rule and a dot in each of the plurality of the sub-matrixes grows from a corresponding original point. The image forming apparatus satisfies a relation of (1) a?0.08 mm and b/a<0.80, or (2) a<0.08 mm and b/a>1.

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: A representative gradation value is set collectively for each pixel group of several pixels each, and then the representative gradation value undergoes multilevel halftoning. From the multilevel halftoning result value obtained in this way, the presence or absence of dot formation for each pixel is set and the image is output. Also, based on the resolution ratio of the image data input resolution and output resolution, if the pixel group is divided, it is possible to divide the pixel group into suitable sizes for processing, so it is possible to improve the output image quality. Furthermore, even when the pixel group is divided, it is possible to share data for processing, so it is possible to save memory. In addition, it is possible to rapidly output high quality images with a simple process.

Abstract: A dither pattern is formed in such a manner that threshold values 1 to 16 are dispersed in regard to the order of magnitudes of the threshold values. First, there is made a calculation of multiplying each value of the image data by a ratio of 1/2. Thereby, there is produced the divided 17-valued data where every value of all pixels is “2”. Next, binarization is carried out for the divided data by using the dither pattern. As a result, binary data at the first pass is obtained. Next, there is obtained the data by a product of a ratio (1/2+1/2) obtained by adding 1/2 to the above ratio and each value of the image data. Binarization is carried out for the image data by using the dither pattern. This produces binary data. Finally, dot data for the second pass is obtained by subtracting data from the binary data.

Abstract: A three-dimensional halftone screen is provided that is suited for multilevel printing. The three-dimensional halftone screen includes a plurality of planes each corresponding to one or more input intensity levels of an input RIPped pixel. Within the planes are screen dots, each associated with one or more output exposure intensity values representing an intensity of an exposure dot corresponding to the input RIPped pixel.

Abstract: A filter for implementing Floyd Steinberg two-dimensional error diffusion algorithms allows high-speed processing of video and images. The filter is shown in direct form with proper bit precision with implementations that permit the filter to operate at high speed. Furthermore, a reduction in the gate count is achieved over the direct form. The results of static timing analysis obtained post synthesis are also summarized.

Abstract: A dither matrix is applied to a high-resolution image to compare the value of each of the pixels that compose it with a threshold value of the matrix and to obtain an output value of the matrix (Dither matrix value) from each comparison. To each pixel value of the image there is applied an algorithm involving simple but displacement operation, namely shifts to the left and shifts to the right. The pixel values of a low-resolution image are output from the applied algorithm.

Abstract: Threshold matrixes for a C-separation and an M-separation of main colors are used to convert a continuous-tone image subjected to color separation into dot patterns for the C-separation and the M-separation. The dot patterns are binary images in which no screen ruling or screen angle is defined. Then, a color image is reproduced by overlaying the dot patterns for the C-separation and the M-separation. When the dot patterns for the C-separation and the M-separation are converted into patterns in the frequency domain, main frequency components obtained by the conversion have a substantially-constant predetermined pattern frequency for all angles, and the intensity distribution of the main frequency components is varied based on the C-separation and the M-separation.

Abstract: A method (and system) of multi-bit halftoning includes comparing values of an image to threshold values of a halftone threshold matrix, and generating output values that provide a greater than minimum level of contrast.

Abstract: The image processing method comprises: a recording failure position determination step of determining a recording failure position on an image corresponding to a malfunctioning recording element; a basic threshold value matrix storage step of storing a basic threshold value matrix set with threshold values used for halftoning of converting multiple-value input image data into dot data of a number of tonal graduations smaller than that of the multiple-value input image data by quantizing the multiple-value input image data; a sub-matrix storage step of storing a plurality of sub-matrices in association with recording failure positions in the basic threshold value matrix, each of the sub-matrices being set with threshold values which are substituted for the threshold values in a partial region of the basic threshold value matrix, the partial region including a pixel position corresponding to the recording failure position and having a width of a prescribed number of pixels; a replacement region determination st

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 and apparatus for creating a print file for printing a 3-D print using a 3-D printing system is described, the 3-D print comprising a plurality of 3-D structures printed on a substrate, each 3-D print structure having a height with respect to the substrate. A two-dimensional source image is input comprising a plurality of image pixel areas. A filtered image is obtained by applying a topographic operator to the source image to generate for every image pixel a representation of a pixel height profile, the pixel height profile corresponding to cross-sections through a 3-D print structure which is to be formed by 3-D printing. Thereby definitions of a plurality of image layers are generated from the filtered image for printing using the 3-D printing system. The print file is output based on the plurality of image layers.

Abstract: The present invention provides an image processing device which is capable of avoiding disappearance of print data such as thin lines by increasing probability in which an original image is stored even after resolution conversion processing is executed to a binary image. In order to achieve this, the present invention may leave the pixels in any of the two lines halftone-processed with same threshold value row after the resolution conversion in a given ratio.

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: A color reduction processing apparatus and method that is simple to configure and adjust produces two-color print image data reflecting the impression of the original full-color image. Each pixel in a full-color image is converted to binarized principal and secondary color print data by principal and secondary color processors respectively using respective threshold value matrices. The threshold values of these matrices, which are calculated from a reference threshold value matrix stored in memory, can be adjusted, via adjustment values, to control the overall density of the principal and secondary colors. The adjustment values can be set in a matrix configuration unit. The binarized principal and secondary color print data can also be further corrected by correction and/or filtering operations performed by a correction processor.

Abstract: Methods of the present invention allow for optimization of color and shades of gray documents prior to their conversion to a monochrome format. If color/gray elements are identified in the document, the distance between them and their intensity is determined. If there are elements with the same or similar intensity in close proximity to each other, colors of some of the elements may be replaced with solid monochrome colors, and/or dithered surfaces, and/or monochrome patterns. Further, the elements may be outlined. These improvements make elements in the document more distinguishable after its conversion to a monochrome format. The described color optimization and outlining may have wide applicability in the Internet Fax technology.

Abstract: A method and system for printing of gray scale images utilizes raster image data. A page is divided into tiles in a two dimensional grid. Tiles are checked for the presence of dither cells for generating gray scale values. Tiles without dither cells are compressed for transmission while tiles having dither cells are not compressed.

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: An image forming apparatus, for forming an image with using distributions of two or more types of dots having different densities per unit area in a same hue, including: a threshold value matrix; and a dot formation determining section for carrying out comparison between a pixel value at a target pixel in the input image and a threshold value corresponding to the target pixel in the threshold value matrix, and for determining, whether to form or not to form any one of the two or more types of dots, wherein threshold values in the threshold value matrix are configured so that a frequency of dot formation is lower, for gradation regions in which a dot density of any of the two or more types of dots is low and/or high, than that for gradation regions in which the dot density is in average level.

Abstract: An image processing apparatus comprising a halftone processing section which executes a halftone process for input image data, wherein the halftone processing section executes the halftone process, by using a dither matrix, the order of producing the dots in the halftone process is consecutive in a main scanning direction, in the pixel block, and the starting position of producing the dots in the pixel block is shifted in the main scanning direction by no less than two dots from the starting position of the adjoining pixel block in the sub scanning direction.

Abstract: An image recording apparatus (2000) is disclosed, which includes forming elements (2002) for forming an image, a memory (2006) indicating relative desirability of utilizing the forming elements (2002) for forming the image, and processing unit (2008) for computing image recording signals using input image signals (2012) and the stored data. The use of a particular forming element is thereby biased dependent upon the relative desirability data for the other forming elements and the corresponding input image signals for the other forming elements.

Abstract: In a threshold matrix generation part 3 implemented by a computer, a tint image in a specified gray level is generated from temporary lighting order set in a matrix area, and a smoothing operation is performed on the tint image, to generate a grayscale evaluation image. The lighting order is modified by changing ordinal numbers in the lighting order of respective positions included in specified areas in the matrix area which correspond to areas around boundaries of halftone dot areas in the tint image on the basis of values of corresponding pixels in the evaluation image.

Abstract: An image processing device converts multi-gradation image data to low-gradation image data for outputting an image of a dot pattern that is formed by a high-density first part formed in a band shape by dots connected in a predetermined direction and a low-density second part formed by randomly arranged dots.

Abstract: A dot pattern with a plurality of pixels representing a two-dimensional image is formed on a printing plate material by applying laser beams, which are turned on and off for each pixel depending on dot pattern data, to the printing plate material in a main scanning direction, while the laser beams are moved in an auxiliary scanning direction that is orthogonal to the main scanning direction. A threshold matrix having an array of thresholds is obtained for generating a dot where the degree of a variation of the dot periphery length in a main scanning direction is smaller, i.e., a dot where the dot periphery length in the main scanning direction has a smaller standard deviation.

Abstract: Appropriate halftone processing is applied to respective regions without any zone segmentation of a document image formed upon mixing a photographic image, character image/line drawing, and the like. Hence, an image is input, an edge image of the image is generated, a smoothed image of the edge image is generated by smoothing processing, and lattice points having a density distribution according to the tone density distribution of the smoothed image are set. A predetermined region is partitioned into polygons, each of which surrounds one of the lattice points, and a threshold matrix used to grow a halftone dot surrounded by each polygon is generated.

Abstract: The input pixels in an image to be halftoned using error diffusion are dithered using a first type of passband dither. A second type of passband dither may also be added to a thresholding matrix used in halftoning. This second type of passband dither may be the same as the first type of passband dither. In such case, the second type of passband dither is a scaled multiple of the first type of passband dither. The halftoning process may be implemented in an application specific integrated circuit.

Abstract: An image forming apparatus performs dither processing on image data to form an image subjected to pseudo-halftone processing. The image forming apparatus includes a dither processing unit that performs dither processing on image data, and a dither pattern generation unit that generates a dither matrix for use in the dither processing, in accordance with an output gradation level. The dither matrix has a size of M×N pixels, and has a plurality of halftone dots arranged in a predetermined pattern in accordance with the output gradation level in order to represent a gradation of each color. The plurality of halftone dots are arranged in the dither matrix such that the halftone dots corresponding to at least two colors are substantially identical in color area ratio to each other in the dither matrix irrespective of a relative position with respective to the colors.

Abstract: A process for the modeling of dots in the generation of a threshold matrix for a screen for the production of a screen form for the printing of image data. The dots are described by model points built up from computed points with an assigned density value. For modeling of ink-jet printing, in the area of overlap of neighboring model points the density values of the computed points are added to form a sum density, the sum density is limited to a maximum possible blackening, and the percentages of the sum density which exceed the maximum possible blackening are distributed to the neighboring computed points. For the modeling of offset printing, in the area of overlap of neighboring model points the maximum of the density values of the computed points is determined as the resulting density and with a filter operation a dilatation of the model points is effected.

Abstract: A normalization threshold side size Nr which serves as an index indicative of how many times the pattern frequency r is repeated in one threshold matrix is defined as Nr=N×r/R where N represents a size of one side of the threshold matrix as the number of pixels, and the threshold array of the threshold matrix is determined such that the normalization threshold side size Nr is of an value greater than 65.

Abstract: A combined dot density (FM) and dot size (AM) modulation halftoning method and system produces a halftone in which both the density and size of the dots are modulated. In addition to modulating the dot size and density, the halftoning method can also explicitly control the size of dot clusters and different intensity levels.

Abstract: A disclosed inkjet recording apparatus for performing recording by jetting a recording liquid onto a recording medium includes an image processing unit configured to obtain an output halftone level by performing halftone processing on input image data, to select a dot arrangement order according to the obtained output halftone level, and thereby to generate dot data where dots are arranged in a grid-like pattern. The disclosed inkjet recording apparatus is configured to use a pigmented ink as the recording liquid when the recording medium is a commercial printing paper, and to record the dots in a staggered arrangement where positions of the dots in odd/even-numbered columns or odd/even-numbered rows in the dot data are shifted in a sub-scanning direction or in a main-scanning direction.

Abstract: A method for generating a threshold value matrix is used in the frequency-modulated half-toning of the image data to be reproduced. A threshold value matrix for a basic screen is generated in that low-pass filters of different width are applied to the bit patterns generated and the threshold value distribution is changed on the basis of the filtered results. Furthermore, the bit patterns generated are examined for specific part patterns and the threshold value distribution is changed in such a way that undesired part patterns no longer occur and, instead, desired part patterns, preferably rounded forms, are contained in the bit patterns generated. By use of a combination of scaling and/or rotation and/or mirroring of the threshold value matrix of the basic screen, threshold value matrices are generated for the printing inks.

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: A printing control method of generating print data to be supplied to a print unit capable of forming dots on a print medium by ejecting ink droplets of at least one type of colored ink containing a color material and a quality-enhancing ink for enhancing quality of a printed material. The printing control method comprises a tone-decreasing step which includes the step of generating transparent dot data by a process configured such that size of first processing-targeted pixels is larger than size of second processing-targeted pixels, the first processing-targeted pixels being targeted for processing in the transparent dot data generating process, the second processing-targeted pixels being targeted for processing in the colored dot data generating process.

Abstract: An image processing apparatus having an arithmetic processing section for quantizing multi-density level image data and converting the image data into digital halftone image data for outputting. The arithmetic processing section is configured to create a plurality of quantized patterns to determined a dot occurrence information sequence, based on a given initial quantized pattern, such that anti-correlation is increased with respect to the dot occurrence information sequence for a pixel that has already been quantized; to add the plurality of quantized patterns to form a dither mask; and to quantize the multi-density level image data by using the dither mask.

Abstract: Even when an image signal is converted into an image signal with a limited amount of toner adhesion, the gradation is prevented from changing rapidly near the limiting value and therefore the image quality is prevented from deteriorating. An amount-of-adhesion converting circuit 301 converts image data for each color plane into first amount-of-toner-adhesion data. On the basis of a preset amount-of-toner-adhesion threshold value table, an amount-of-toner-adhesion reduction computing circuit 303 converts the first amount-of-toner-adhesion data for each color plane into second amount-of-toner-adhesion data with a limited amount of toner adhesion. Then, an image signal converting circuit 304 converts the second amount-of-toner-adhesion data into an image signal. In such a method, since parameters in the amount-of-toner-adhesion threshold value table are set arbitrarily, a rapid change in gradation can be suppressed near the limiting value.