Abstract: A tone dependent green-noise error diffusion method includes setting a first threshold and a second threshold, and determining a two-level value of a color level of an input image according to the first threshold and the second threshold; subtracting the two-level value from the color level value to generate an error value; performing an error diffusion on the error value to generate an error diffusion accumulation value; adjusting the color level according to the error diffusion accumulation value; performing a hysteresis filtering on the two-level value to generate an output dependent feedback value; and adjusting the color level according to the output dependent feedback value.

Abstract: A mutual optimization method for class matrix and diffusion weighting used in a halftone image processing technique and a mutual optimization system thereof are provided. In the method, a mutual optimization of a plurality of diffusion weightings and a class matrix used in a dot diffusion process is performed based on a concept of simulated annealing in order to avoid converging to local solution, so as to ensure an image quality of a halftone image generated by the dot diffusion process. Besides, since the mutual optimization method is for a hexagonal class matrix, a block effect appearing in the halftone image can be significantly reduced.

Abstract: The present invention discloses a digital halftoning method. The method comprises steps of: (a1) dividing an original image into non-overlapping blocks; (a2) obtaining a Least-Mean-Square trained (LMS-trained) filter by comparing at least a training image and a halftone result corresponding to the training image (a3) optimizing a class matrix with the LMS-trained filter, which involves the diffused area and the diffused weightings; and (a4) processing the non-overlapping blocks by performing a dot diffusion procedure with the optimized class matrix and the diffused weightings to generate a halftone image corresponding to the original image. A detailed class matrix optimizing method as in the above-mentioned step (a3) is also disclosed.

Abstract: This disclosure relates to decreasing the required buffer memory capacity while reducing the impact of an arithmetic error in error diffusion processing. A quantization circuit (4) quantizes input image data and outputs an output code. The quantization error generated in the quantization circuit (4) is calculated by an inverse quantization circuit (5) and subtracter (6). The calculated quantization error is stored in a buffer (8). Since the buffer (8) only needs to have a size capable of storing the quantization error, the size can be made smaller than before. A diffusion filter (9) diffuses the quantization error using a quantization error or the like, which is stored in the buffer (8). A latch (3) and bit connector (1) can usefully reduce the impact of an arithmetic error in error diffusion processing on the next input image data.

Abstract: A printed sheet handling system and method for use with lazy-portrait narrow-end to narrow-end (LPEE) formatted pages web printed pages to produce document sets includes: a printer to print LPEE formatted paired document pages printed in 1 to N order and face up on a first half of the web and printed in N to 1 order and face down on a second half of the continuous web; a slitter that divides the LPEE formatted printed web into two streams of sheets, with one in 1 to N order and the other in N to 1 order; collecting both streams into separate stacks; flipping the N to 1 stack of sheets; and then withdrawing sheets from the tops of both stacks for cutting into pages, collating, and assembly into correctly aligned and page number-sequenced document sets.

Abstract: The present invention transforms a source device colorant value to a destination device colorant value, by determining whether all non-black colorant values of the source device colorant value are zero, transforming the source device colorant value to a colorimetric value using a source device model, transforming the colorimetric value to a gamut-mapped colorimetric value using a user-selectable gamut-mapping model, and selecting a destination device colorant value based on the determination. In a case where all of the non-black colorant values of the source device colorant value are zero, the destination device colorant value is selected so that its black colorant value reproduces a lightness of the gamut-mapped colorimetric value, and all of its non-black colorant values are zero. Otherwise, the destination device colorant value is selected so that a combination of its non-black and black colorant values reproduces the gamut-mapped colorimetric value.

Abstract: Mapping an input color space into a colorimetric subspace can generate a target colorimetry space. Initial device color values can be used to generate an initial reference colorimetry space. A penalty error between the target colorimetry space and the reference colorimetry space can be minimized by generating a next reference colorimetry space based on subsequent device colors.

Abstract: An image processing apparatus executes an error diffusion process to multivalue image data consisting of a plurality of density components. A first processor executes the error diffusion process by changing at least one of a quantization threshold value and a quantization diffusion coefficient which are used for the error diffusion process based on a value of the multivalue image data of the density components or a value calculated from the multivalue image data value. A second processor executes the error diffusion process by setting the quantization threshold value and the quantization diffusion coefficient which are used for the error diffusion process into fixed values. An error diffusion processing controller controls to execute the error diffusion process to at least one color among the density components by the first processor and execute the error diffusion process to other density components by the second processor.

Abstract: The image processing method converts an input image having multiple tones into an image having fewer tones than the input image, for image recording by a recording head including a plurality of recording elements arranged in a prescribed direction. The pixel values of pixels of the input image are quantized in a processing direction which is set to a direction substantially parallel to a relative conveyance direction of a recording medium with respect to the recording elements when recording onto the recording medium is performed by means of the recording elements. The pixel value for a pixel under processing is quantized according to the result of a comparison between the pixel value for the pixel under processing and a threshold value for the pixel under processing. An error with respect to the pixel under processing caused by quantizing the pixel value for the pixel under processing is diffused into an unprocessed pixel in a periphery of the pixel under processing.

Abstract: Machine-enabled methods of, and system, and processor readable media, embodiments for, tone quantization error diffusion.

Abstract: A method (300) is disclosed of performing chromatic adaptation. The method (300) predicts final colour data viewed under a final illuminant from initial colour data viewed under a initial illuminant. The method (300) receives (310) the initial and final illuminant spectra and spectral sensitivity functions of the colors between which chromatic adaptation is to be performed. A linear chromatic adaptation transform is then determined (320) for transforming the initial color data to the final color data. The linear chromatic adaptation transform is determined (320) by minimising the residual error between color data predicted using the chromatic adaptation transform and the final color data. Different spectral bands of the illuminant spectra and the spectral sensitivity functions are weighted based on the contribution made by each spectral band to a predefined function. The method (300) then applies (330) the linear chromatic adaptation transform to the initial color data.

Abstract: Methods and apparatus are provided for electronically trapping a selected digital color image pixel. A plurality of pixels that surround the selected pixel are identified, a colorant value of each of the surrounding pixels is compared with a corresponding colorant value of the selected pixel, one of the surrounding pixels is identified to control trapping of the selected pixel, and the selected pixel is trapped based on a relationship between a colorant value of the selected pixel and a corresponding colorant value of the identified controlling pixel.

Abstract: The disclosed system and method provide a binary image generation method. Used, for example, in a digital reprographic system, the method is suitable for eliminating printing artifacts for high addressable binary digital output, such as digital copies, using an optimized ordered error diffusion method with dynamically computable quantization error and dynamic binary output calculation.

Abstract: A printing control method of generating dot data representing a state of dot formation at each pixel in a printed image represented by an given image data, by formation of dots in respective pixels with the at least one colored ink and the quality-enhancing ink available in the print unit. This process includes a processing mode configured to make a quality-enhancing ink dot-recording rate for pixels belonging to a peripheral area lower than the quality-enhancing ink dot-recording rate for pixels belonging to a center area.

Abstract: The state of an HDD provided in an image processing apparatus is divided into a plurality of levels and information is given to call user's attention when the state of the HDD is set at a level which indicates that attention should be paid to the state of the HDD. When the state of the HDD is set at a level indicating that the HDD should be exchanged, a warning is given to the user and information indicating that the HDD should be exchanged is issued to a service center. Further, data of the HDD is backed up in an external device if the state of the HDD is set at a level indicating a state which is set up immediately before the HDD becomes faulty.

Abstract: A device including: an acquirer acquiring image data having an M-value (M?3) pixel value; a memory storing nozzle information; another memory storing error diffusion matrices having different diffusion ratios of an error; a selector selecting specific pixel data in the image data; an N-value converter converting the M-value to an N value (M>N?2); a diffuser diffusing the error to pixel data not subjected to the conversion in the image data according to the error diffusion matrix by using a difference between a selected pixel data value before and after conversion as the error; a generator generating print data defining nozzle dot information corresponding to the image data after the conversion; and a printer. The diffuser selects a specific error diffusion matrix for each selected pixel data according to the nozzle information, and diffuses the error to the pixel data not subjected to the conversion.

Abstract: An image forming device includes a quantization unit which quantizes each pixel of an M-level gradation input image into one of N levels (M>N?2) through an error diffusion process. An operation unit performs a predetermined operation according to a position of a target pixel to a gradation value of the target pixel before quantization when the gradation value of the target pixel is equal to a specific concentration.

Abstract: Diffusion dithering can be performed efficiently by applying a set of diffusion filter weights with one or more shift, add, and/or subtract operations. An existing diffusion filter can be approximated with dyadic rationals, thereby allowing division operations in applying the filter weights to be performed with bit-shifting operations. An algorithm is identified to calculate the product of a set of filter weights and a pixel error, where the algorithm performs the calculations using one or more shift, add, or subtract operations.

Abstract: An apparatus and method for calibrating a multi-color imaging system are provided. Color values are measured for each of the different color patches, and compared to target process-sensitive colors color values, representing a weight-adjusted memory color. An error value is calculated. The error value represents a deviation of the measured color values from the target color values. The input values for each colorant then are independently adjusted to reduce the error value to a predetermined degree.

Abstract: In the method, the membership image is produced through a multi-stage process that contemplates a first punctual classification stage generating a rough membership image, followed by a low-pass filtering of regionalization of the image through a down-sampling of the image followed by an up-sampling of the image, and in a further step of merging the regions that overcomes the superposition effects induced by the low-pass filtering operation. The so generated membership image contains semantic information of the input image that may be used for effectively implementing an adaptive correction/improvement of the color of the input image. For an adaptive correction/improvement of the color, the encoded data of the generated membership image is fed in parallel to the data of the real image to an adaptive modification block of the color of the image pixels.

Abstract: A method for processing a digitized continuous tone image for reproducing the image by a printing device, including (a) inputting a tone value of an input pixel of the image; (b) applying a plurality of levelsplit curves to the tone value, thus obtaining a plurality of level values, wherein each specific levelsplit curve of the curves corresponds to a level defined by (i) a combination of a dot density and a dot area; or (ii) an overlap of a plurality of such combinations; (c) inputting the plurality of level values to an error diffuser for obtaining an output pixel value for reproducing the image; wherein a fraction of the output pixels to be filled by an overlap of levels depends on the level values and is independent of the error diffuser.

Abstract: An error adding step adds together input multi-tone image data and peripheral error information. An adding/subtracting step adds to or subtracts from multi-tone image data calculated by the error adding step, a random number in a matrix prepared for each set of pixels of the input multi-tone image data. A quantizing step quantizes multi-tone image data calculated by the adding/subtracting step into image data, the number of bits of which image data being smaller than the number of bits of the multi-tone image data calculated by the adding/subtracting step. An error calculating step calculates an error based on the multi-tone image data calculated by the error adding step and the image data quantized by the quantizing step. An error storing step stores the error calculated by the error calculating step for each peripheral pixel.

Abstract: A halftone reproduction processing section (29) of an image processing apparatus (13) has a control part that conducts a halftone processing of input image data by subjecting it to an error diffusion processing, selects input image data on at most one, namely, one or no input image data from the input image data on at least seven colors, namely, primary colors of cyan, magenta, and yellow used as visible colors for forming an image on a recording medium, secondary colors of red, green, and blue that are the complementary colors of the visible colors, and black, and subjects the input image data on the other colors to a different error diffusion processing.

Abstract: A method and system for performing error diffusion are disclosed. An ordered set of pixels, including a pixel intensity value for each pixel, is received. Each pixel intensity value includes a value within a range from a low value to a high value, inclusive. An initial error value is also received. Based on the pixel intensity values and the initial error value, a pixel value for each pixel and an updated error value are computed substantially simultaneously with each other.

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: An improved digital halftoning method that uses an input image's global gray levels to determine the local gray levels of a monochrome output image. Input multi-bit pixels grouped into two-pixel-by-two-pixel local subcells are variously aggregated into one or more larger supercells. The size of said supercell(s) is related to and limited by the size of the global input bitmap. A final monochrome gray level is derived from said supercell(s) and distributed within contained subcells. Subcell gray levels are expressed as interim whole monochrome pixels and gray level remainders. A comparison is made of the final supercell and the summed interim subcell monochrome gray levels. An ordering of the remainders is used for assignment of additional monochrome pixels, if necessary, to yield final subcell monochrome gray levels. Gray level rounding errors thus are quantized by reverse diffusion until a monochrome gray level for each of the global image's two-pixel-by-two-pixel local subcells is derived.

Abstract: A method for processing image data that employs a stamp field that contains data representing a distance metric for use with a variety of error diffusion operations. The distance metric possesses distance-order preservation permitting the distance from a previous dot to be determined by incrementing the distance metric, without knowing precisely where the previous dot was printed.

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: The amount of moiré in halftone printed images is reduced using unique moiré intensity functions and moiré vectors in a halftoner. In various embodiments, moiré phase angle zones are determined over the full field of an image and high addressability units in the full-field moiré phase angle zones of the image are adjusted, including in an iterative manner, until they significantly reduce the moiré. A useful relationship between halftoner memory locations and moiré phase angle zones in a full field image is determined. The moiré that occurs in a halftone image is quantified and moiré compensation values obtained are then used to generate an inverse moire amount which is used to compensate for the moiré.

Abstract: A method for eliminating moire in scanned digital image comprises the steps of using an average circuit for taking weighted average and error diffusing a gray level difference between an error diffusion pixel Gij and neighbor pixels to neighbor to obtain output image pixel Y?ij; using a second adder for subtracting the error diffusion pixel Gij from the output image pixel Y?ij to obtain a neighbor image error dij; using a error filter H(z) to process the neighbor image error dij to obtain a corrected pixel error H(d(i,j)); and using a first adder for adding the corrected pixel error H(d(i,j)) and the input image pixel Yij to obtain the corrected error diffusion pixel Gij, and then jumping to first step until all pixels being processed. The method provides real time treatment for eliminating moire and provide smooth image.

Abstract: A method of embedding an image into two images by performing a digital halftoning process on a Cartesian product of color spaces to embed the image into the two images. A digital halftoning process includes an iterative isotropic halftoning process. The iterative isotropic halftoning process for each iteration if Outimage has not changed between two iterations or maximum number of iterations reached, then exit the iterations loop.

Abstract: A method for halftoning includes the steps of defining a first set of weight sets, and defining a second set of weight sets. A first error associated with a first pixel location of a plurality of pixel locations is diffused to a first neighboring at least one pixel location using a first weight set selected from the first set of weight sets, and a second error associated with a second pixel location of said plurality of pixel locations is diffused to a second neighboring at least one pixel location using a second weight set selected from the second set of weight sets. The first diffusing step and the second diffusing step are alternately performed along each scanline in the image to reduce visual artifacts.

Abstract: The image recording apparatus comprises: a recording head including recording elements which record an image onto a recording medium; an abnormal recording element specification device which specifies an abnormal recording element from the recording elements of the recording head; a correction dot pattern setting device which sets a correction dot pattern for preventing an image abnormality due to the abnormal recording element; an image processing device which generates dot data by performing quantization processing on image data using the correction dot pattern set by the correction dot pattern setting device; and a drive device which drives the recording elements according to the dot data generated by the image processing device.

Abstract: A method and apparatus for performing error diffusion of a multiresolutional representation of an image is disclosed herein. In one embodiment, an image is received as a pixel representation. The image is converted from a pixel representation to a multiresolutional representation having multiresolutional coefficients. Each multiresolutional coefficient is quantized and an error is passed to one or more other multiresolutional coefficients as specified by an error filter. Finally, the resulting quantized image is produced as output.

Abstract: The invention is a method for printing a color proof from an initial halftone bitmap file (10) having individual dots (10a, 10b, 10c, 10d) using a spatial filter (20) which is created from a calibration curve (30) for a printing press (380). The method further consists of sending an initial halftone bitmap file consisting of individual dots to the spatial filter creating a filtered output (40), quantizing the filtered output from the spatial filter to “n” levels to create a quantized image (50), transmitting the quantized image to a color printer (70), and printing a halftone color proof (80) on the color printer.

Abstract: An image processing apparatus includes a dividing portion that divides input multivalue image data into a plurality of bands, an error diffusion process portion that carries out an error diffusion process on each divided band to quantize each pixel, and a controlling portion that controls the dividing portion and error diffusion process portion. The error diffusion process portion, following control by the controlling portion, operates in a first mode to repeat the error diffusion process not accompanying quantization given times on each noted pixel included in a given line of the each band (head line, etc.), and operates in a second mode to carry out the error diffusion process on the each band sequentially from the head line of the each band on the basis of an error value obtained in the first mode to put out quantized data.

Abstract: There has been a demand to accelerate image data conversion through the use of the error diffusion method. To convert image data, it is determined whether a specified block process condition is satisfied on the basis of a gradation value for each pixel in a target block. When the block process condition is true, a process is performed to diffuse a gradation error for the entire target block and convert image data for pixels in the target block at a time. Even when the block process condition is false, it is determined whether to form a dot in the target block. When it is determined that no dot should be formed, a process is performed to diffuse a gradation error for the entire target block to the unconverted pixels in another block and convert image data for pixels in the target block.

Abstract: Error diffusion halftoning systems and methods propagate the error both within a color layer and between the color layer being halftoned and subsequent color layers yet to be halftoned. Threshold array halftoning systems and methods diffuse error to subsequent color layers after a color layer has been halftoned using a threshold array. A color continuous tone image is separated into color layers. A plurality of weighting factors are selected that control how error is diffused to subsequent color layers as each color layer is halftoned. A first color layer is halftoned using error diffusion or threshold array halftoning. An error layer is generated from the first halftoned color layer and the first color layer. A modified second continuous tone color layer is generated based on at least one error layer and the corresponding weighting factor. That modified second continuous tone color layer is then halftoned and the process is repeated.

Abstract: When image data is converted into an expression format based on the dot on-off state, such conversion is performed in a unit of a raster group comprising a predetermined number of adjacent rasters. When this is done, the binarization errors occurring in each pixel of the last raster located in the last position of such raster group are diffused into surrounding pixels and stored in a first storage unit. The errors are read out from the first storage unit for dot on-off state determination regarding the first raster of the raster group adjacent to the above-mentioned last raster, and binarization errors occurring in connection with this determination are stored in a second storage unit that permits faster reading and writing of data than the first storage unit.

Abstract: A color imaging technique includes setting a target value in a device-independent first color space and mapping the target value to a substantially complete point set in a second color space. The point set may include a plurality of points, each of which define substantially the same colorimetric value via a unique combination of colorants. After mapping the target value to a substantially complete point set, a point may be chosen. Moreover, after choosing a point in the point set, device-dependent colorant values defined by the point may be determined. In this manner, the invention may provide control over the colorants that are used to image a particular color.

Abstract: In order to acquire a good binary image at all levels of gray scale, an image processing apparatus for quantizing input multivalued image data by a multivalued error diffusion method, selecting a predetermined dot pattern based on the quantized image data and outputting a binary image is configured to have an error calculation division for calculating corrected value from a pixel value and a processed pixel diffusion error of an input image, and calculating a quantization error from an output density level corresponding to the corrected value, an image generation division for first acquiring a diffusion coefficient corresponding to a pixel value of the input image, and distributing the quantization error to surrounding pixels according to a weight assignment by the diffusion coefficient to generate the binary image, a diffusion coefficient generation division for generating a plurality of candidate diffusion coefficients, a computing division for acquiring an evaluation value for the binary image generated by

Abstract: Disclosed is a method, system, and program for generating a table for enhancing the print quality of input raster pel data. An output value is generated for different patterns of pel data. Each output value indicates a sub-pulse width power to charge a sub-pel region within a pel and position information indicating the justification of the sub-pel region within the pel. A look-up table is formed from the generated output values that enhances print quality.

Abstract: Methods, devices and systems for overflow error diffusion in image processing are provided. A method includes calculating error values, em, corresponding to differences between modified intensity values for a number of pixel locations and one or more threshold values, where em represents an error value associated with an mth pixel. The method further includes diffusing a calculated overflow error value associated with each calculated error value, em, to at least one pixel neighbor of the mth pixel location.

Abstract: According to the embodiment of the present invention, provided is an image error diffusion method for changing, an error diffusion ratio relative to the each pixel of an image. Further, according to another embodiment of the present invention, in order to generate a half tone image that highly correlates with an original image without losing the characteristics of the image, first, the characteristics of the input image are extracted, and then, the obtained results and input/output information are used to adjust, for each pixel, the diffusion state of a quantization error.

Abstract: An error diffusion method is provided where a plurality of n error values derived from processing one or more previous scanlines of input pixel values are sub-sampled without the n error values being stored in a buffer to derive m error values (m<n). In one example, a reduction factor R is used according to m=n/R. In another example, a two-dimensional reduction operation is performed. The m error values, rather than the original n error values, are used as input for subsequent error diffusion operations. This allows for storage of m error values rather than n error values and, thus, error buffer requirements are reduced. Image quality has been found to be comparable to conventional error diffusion operations when the reduction factor used is maintained within reasonable limits. The sub-sampling operation can be accomplished according to any suitable method.

Abstract: Apparatus and methods for flexible digital halftoning are provided in which novel pattern choices are allowed by not restricting the basic halftone patterns to grow sequentially. Rather, positions in a threshold array allow multiple transitions between on (i.e., printed with toner/ink) and off (not printed) as a function of the input value at the corresponding position. In one embodiment, multiple threshold matrices are employed and the output decision is a vote (e.g., exclusive OR) of the outputs of the individual threshold matrices. In another embodiment, each position contains an arbitrary bit vector to express the output for each input. In yet another embodiment, space efficiency may be achieved by sorting the arbitrary bit vectors into collections of adjacent decisions for a given input value, such as into bytes.

Abstract: A halftoning method and apparatus reduces the occurrence of unaesthetic color print output associated with the different relationships found in the numeric data contained within the color data planes. The calculation, modification and distribution of error values, resulting from the mismatch between color plane values and firing thresholds, are performed in a manner that minimizes unaesthetic conditions. Error values are modified by use of error modification functions, bitmaps and matrixes. Firing decisions are based on a comparison of the modified error.

Abstract: A halftoning apparatus free of the occurrence of moiré and other artifacts under a simple technique. In the apparatus, a binarizing section converts the multilevel value of a given noteworthy pixel of the multilevel input image into a binary value while pixels of the input image are scanned successively, an error diffusing section diffuses an occurred error in binary value with respect to the noteworthy pixel to unscanned pixels adjacent to the noteworthy pixel by one diffusion technique, and an error diffusion technique changing section changes the diffusion technique to another in accordance with a predetermined manner as the scanning of the successive pixels of the multilevel input image progresses.

Abstract: An image processing apparatus capable of providing an output image which is close to an actual image observed with human eyes is structured in the following way. An image data from an input unit is supplied from an output unit with a reduced number of gray levels. Based on an input value, an occurrence probability determining unit outputs dot occurrence probabilities d1-d3 for reproducing respective gray levels. Initial thresholds t1-t3 from an initial threshold generating unit are corrected based on a processed pixel in the vicinity of a pixel to be processed, and thus correction thresholds t?1-t?3 are derived. A selecting unit selects which dot is to be output based on the correction thresholds and occurrence probabilities.

Abstract: An adaptive halftoning method where the difference between a digital image and a filtered digital image is introduced into the system on a pixel by pixel basis is disclosed.