Abstract: A method of reducing mosquito noise in a digital image. As mosquito noise is often most plainly visible in the “background” of an image (e.g., the sky or some other backdrop to objects within an image), the luminance value of the background of the image is first determined. Then, the luminances of the pixels of the image are compared against this “background luminance” to determine which should be considered as part of this background. The luminances of these background pixels are then averaged so as to smooth out the representation of the background, and reduce mosquito noise.

Abstract: An image processing apparatus includes: an image data acquiring unit that acquires image data formed of plural pixel data having an M-ary (M?3) gradation value; a grouping unit that divides the image data acquired into J (J?2) image data areas and sections the J image data areas into K (2?K?J) groups; a pixel data selecting unit that selects, for each of the image data areas forming the respective groups, predetermined pixel data out of pixel data included in the image data area; an N-arization processing unit that applies the N-arization (M>N?2) processing to the pixel data selected on the basis of a predetermined threshold value; and an error diffusing unit that diffuses a difference between a value of the selected pixel data and a value after the N-arization processing for the selected pixel data to pixel data not subjected to the N-arization processing, wherein the error diffusing unit diffuses the difference in directions different from one another in two or more groups of the K groups.

Abstract: An apparatus and method for improving qualities of motion and still images to be output in a mobile communication terminal. An error-reflected-value table is provided to reduce a computation amount while applying an error diffusion process. The table includes quantization-error-reflected values pre-computed according to maximum values of quantization errors and error-reflected ratios of neighboring pixels. When quantization errors of a specific pixel of an original image selected in a process procedure are computed, error-reflected values of neighboring pixels are determined. Pixel-by-pixel error values are stored by accumulating error-reflected values related to pixels. When error-reflected values of neighboring pixels around all the pixels of the original mage are completely computed, an image in which quantization errors are diffused is generated when the error-reflected values are added on a pixel-by-pixel basis.

Abstract: A method for multi-toning an input digital image having input pixels with two or more color channels to form an output digital image having modified output levels. The method includes determining modified output levels using a combined error signal formed from intermediate error signals for each color channel together with an error signal offset value, and adjusting the input levels for the nearby pixels responsive to weighted error signals.

Abstract: A device and method is provided for breaking up undesirable patterns in vector error diffusion when the sum of inputs is near fraction values of the total input range. In the method, the value of the sum is calculated modulo the maximum input value. The mod value tendency to produce limit cycles is then determined for multiple planes in a manner similar to that for an individual plane. The threshold process for the vector calculation can then be modified to break up the cycles that occur in the combinations of the multiple colors. Typically, the largest of the individual plane modifications and the vector sum mod value is used for threshold modification. At least two different types of threshold modifications are possible: (1) random or psuedo-random noise address to the threshold; and (2) non-contiguous regions of threshold.

Abstract: A method and system for providing a halftoned image is disclosed. The method and system comprise scaling the halftoned image by performing pel repetition utilizing an error diffusion algorithm such that artifacts are minimized. According a system and method in accordance with the present invention performs pel repetition using error diffusion technology, so that any resulting “artifacts” are realized as high-frequency image addition, making them much less visible. A system and method in accordance with the present invention provides adjustability in the computational complexity of the scaling, so that quality can be traded off continuously against the amount of processing power required.

Abstract: What is disclosed is a system and method for diffusing pixel error in a halftoning process in a color management system. The present method divides a modified CMYK input into a real and imaginary portions. The real portion is the coverage achieved by a physically realizable positive dot. The imaginary portion comprises a an imaginary negative dot and an imaginary excess dot. Each of these dots are processed separately, on a per-pixel basis, in a novel CMYK to CMYKKpRGB conversion discussed in detail herein. Hierarchical thresholding is preformed on the conversion output to produce a high-quality halftone result. A cumulative pixel error sum is derived therefrom and combined with the input CMYK coverages of a next pixel. All pixels are processed. The halftone output generated hereby has the pixel error compensated. Other embodiments are provided.

Abstract: A method for diffusing errors in a display device. Each frame of an input video signal is separated into at least two independent subframes. An error diffusion process is applied to each subframe of at least two independent subframes. The errors transmitted reciprocally from subframes are partially mixed, and the error diffusion process is applied to the mixed errors at each independent subframe.

Abstract: In an image processing method for carrying out a plurality of types of halftoning processing expressing in combination amplitude modulation having the number of tone levels smaller than that of an input image and area coverage modulation, selectively or in parallel, the plurality of types of halftoning processing comprises processing providing output image color and tone substantially identical mutually.

Abstract: The image processing method for performing halftoning of a digital image constituted by an array of pixels having grayscale values which correspond to a content of the digital image, the method comprises the steps of: grouping the pixels constituting the digital image into a first group comprising pixels in pixel positions from which a quantization error generated through quantization is diffused to a peripheral pixel, and a second group comprising pixels in pixel positions from which the quantization error generated through quantization is not diffused to a peripheral pixel; performing a first quantization process on the pixels belonging to the first group using a threshold matrix; determining the quantization error generated during the first quantization process; diffusing the quantization error obtained in the quantization error determining step to at least one non-quantized pixel belonging to the second group which is adjacent to the pixel subjected to the first quantization process; and performing a seco

Abstract: Image processing is carried out by transforming image data to image data having spatial frequency components, by judging whether the absolute values of the coefficients of the predetermined frequency components of the transformed image data are equal to or more than a predetermined value, by modifying the coefficients of the AC components of the image data depending on the result of the judgment, by inversely transforming the image data having the modified coefficients to image data having spatial coordinate components, by comparing the gray levels of the inversely transformed image data with predetermined values, and by transforming the gray levels to quantized levels corresponding to the result of the comparison. By carrying out proper image processing corresponding to the characteristics of the image, the number of gray levels of the image can be decreased while the characteristic portions of the original image are maintained properly.

Abstract: In accordance with the present invention, a system and method are described for producing pure gray tones on a multi-color document output device that includes a system for operating on device independent color data having multiple color components, which color data corresponds to one or more associated electronic documents. The system and method function to extract gray data by the use of tristimulus values in a range specified by a functional relationship of a selected tristimulus value.

Abstract: A matrix of processing object frame data and a matrix of temporally consecutive next frame data of the processing object frame data, are prepared as matrices for error diffusion processing. An error generated at a pixel position in a frame, which is represented by the processing object frame data, is diffused to a corresponding pixel in a frame represented by the temporally consecutive next frame data of the processing object frame data.

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: 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: A watermarked halftone image is generated from a continuous tone image by performing error diffusion halftoning on the continuous tone image while adding a watermark to the halftone image during the halftoning. A location of the watermark in the halftone image may be based on prediction criteria. Error caused by adding the watermark may be diffused into the halftone image.

Abstract: An image-processing apparatus for quantizing multi-level (M-level) image data into N-level values, where M>N>1, using a multi-level error-diffusion process or a minimum-average multi-level error method is disclosed. The image-processing apparatus includes: means for outputting correction data; means for setting a quantization-threshold value; means for comparing the correction data and the quantization-threshold value so as to output N-level image data; and means for calculating an error generated with generating the N-level image data.

Abstract: Embodiments are directed to image processing methods to improve display quality while using a limited number of pulses and to correct the error between the reflectance and the desired gamma. The complexity of the hardware used for driving a display device may then be reduced to minimum. In addition, in various embodiments the method can also be used to compensate for the change of an optical response curve due to batch variation, temperature change, photo-exposure or aging of the display device.

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 plurality of items of color-component data representing an image are input and a plurality of items of output color-component data representing an image to be reproduced by a printer are decided and output. In the case of an image in a specific area in which an entered image is represented by at least two items of color-component data, any one item of color-component data is decided upon as output color-component data.

Abstract: A system and method of reducing noise in output image data is provided. Grayscale image data having a plurality of pixels is received and processed. During processing, pixels which may produce noise are identified, and a mask associated with the image data is generated. The mask provides information related to the pixels, such as opaque and transparent regions for overlaying the pixels. The image data and the mask are compressed and stored. The mask assists in preventing the identified pixels from being visible when the image data is output, thereby reducing the noise in the image.

Abstract: An image processing apparatus can obtain a copy image having excellent reproducibility with a relatively simple structure of a processing unit that processes image data. The image processing apparatus generates image formation data by processing image data. A gradation processing unit binarizes the image data according to an error diffusion process so as to convert the image data into binary image data. A character/line drawing detection unit determines whether a part of the binary image data corresponds to a character/line drawing portion that consists of characters or line drawings so as to detect the character/line drawing portion. An image processing unit applies an image processing to the part of the binary image data by using an image processing method according to a result of determination of the character/line drawing detection unit.

Abstract: Embodiments include a method for halftoning a source image. The halftoning includes error diffusion processing of a first separation of plural color separations of a pre-rendered image after error diffusion processing a second separation of the plural color separations of the pre-rendered image. The error diffusion processing of the first separation including, for respective pixel values corresponding to the first separation, choosing respective magnitudes of the respective pixel values as a function of the error diffusion processing of the second separation. A rendered image is output which comprises the same plural color separations. The output rendered image is populated with, for the first separation, pixel information based on the respective magnitudes.

Abstract: The image processing method for obtaining a quantized image from a multiple tone image, the method comprises: an image dividing step of dividing an input image into a plurality of image blocks of a unit block size; a threshold value matrix specification step of specifying threshold value matrices for the input image with respect to each of the image blocks from a plurality of threshold value matrices including a first threshold value matrix having the unit block size and a second threshold value matrix dividable into a plurality of sub-matrices each having the unit block size; and a threshold value matrix setting step of setting threshold value matrices in image blocks for which the second threshold value matrix has been specified as the threshold value matrix, in such a manner that adjacent positional relationships between sub-matrices formed when the second threshold value matrix is divided into sub-matrix units are preserved.

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: An image processing device includes a memory that is adapted to store an input image; an inverted image generator that is adapted to generate an inverted image, the inverted image corresponding to a predetermined part of the input image; a target image generator that is adapted to generate a target image, the target image including the inverted image and the input image; a quantization unit that is adapted to quantize the target image, in accordance with the error diffusion method; an image extractor that is adapted to extract an output image from the quantized target image, the output image corresponding to the input image; an output unit that is adapted to output the output image extracted by the image extractor.

Abstract: A system and method for determining composite grays using device values. Device values are received from image data on which color separation was performed. Gray component replacement are determined on black point device values by using target lightness values, target chromaticity values, and target black device values. A printing device and a computer readable media having computer instructions for implementing the method of determining composite grays are also provided.

Abstract: Before image data are screened for the subsequent exposure of a printing form, files needed for the screening step are changed in such a way that the values of individual elements in the data fields are changed. The number of elements whose values are changed is determined by evaluating contiguous regions within the data fields. These can be, for example, threshold value matrices in which individual matrix elements are set to a value corresponding to the color white, or which, for the half-tones, are calibrated to a reduced value of the full-tone density. In the latter case, the full-tone image points are screened with a frequency-modulated screen.

Abstract: A method and system for processing image data in an image processing device for a plurality of pixel positions within a plurality of scanlines. The method and system includes storing a starting stamp value and a plurality of delta stamp values for the scanline. The stored values being used to generate a pixel stamp value for an input pixel in the scanline, by adding a starting value or previous pixel stamp value and the stored delta stamp value for the input pixel. Further includes receiving an input pixel intensity value for the input pixel and determining an output pixel intensity value. Subsequently, if the output pixel intensity value for the input pixel is equal to a value for a dot or hole the delta stamp values for at least one pixel having a location previous or subsequent to the input pixel can be updated.

Abstract: A quantizing unit quantizes a pixel of interest of an input image. An error detector calculates an error generated upon quantizing the pixel of interest. An error diffusion matrix diffuses the error to non-quantized pixels, which are separated by a predetermined distance from the pixel of interest and are located in a ring pattern, based on an error diffusion matrix.

Abstract: A quantizing unit, error detector, error diffusion matrix, and adder quantize a pixel of interest of an input image by an error diffusion method. A calculation unit and gain adjuster calculate a value to be added to the pixel of interest with reference to quantized pixels. The adder adds the calculated value to the pixel of interest. A control unit controls the calculation of the gain adjuster.

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: An image processing apparatus configured to generate recording data used in an image forming processing for carrying out an image formation by performing a recording scan by plural times on a same image region on a recording medium, includes a division unit for dividing input image data into image data for each recording scan, a quantization unit for quantizing, based on the divided image data for each recording scan, the image data for each recording scan, and a generation unit for generating, based on the quantized image data for each recording scan, recording data for each recording scan, in which the division unit divides the input image data into the image data for each recording scan based on a division rate periodically varying in accordance with a spatial position of an image represented by the input image data.

Abstract: A method for multitone processing an N level digital image to produce an M level digital image wherein M<N, includes the steps of: determining M reconstruction levels based on the gray level distribution of the N level image; and applying multilevel dithering to the N level digital image using the M reconstruction levels to produce the M level digital image.

Abstract: In an image forming system, an information processing apparatus (host computer) outputs print data to a printer connected to the apparatus through an interface. The apparatus includes an interface identifying module for identifying the type of the interface, a query module for determining, based on the identified interface type, a quantization method for quantizing print data and/or a compression method, and an image processing module for performing quantization and/or compression on the print data by the determined quantization method and/or compression method. The apparatus outputs, to the printer, the print data processed by the image processing module.

Abstract: An image processing apparatus is provided that restrains image quality deterioration of image data read with a resolution in a sub-scanning direction set lower than a resolution in a main scanning direction from a document containing text, halftone photographs, line drawings, photographs, etc. An image processing apparatus performs the tone reproduction processing by applying error diffusion processing to the image data that has undergone processing of making the resolution in the sub-scanning direction equal to the resolution in the main scanning direction when the resolution in the sub-scanning direction is lower than the resolution in the main scanning direction and applying dither processing to the image data in other case. When the resolution in the sub-scanning direction is lower than the resolution in the main scanning direction, the halftone processing is applied to the entire image data that sharpness and smoothing processing has been performed.

Abstract: A method for multi-level error diffusion halftoning an input digital image to form an output digital image with reduced error diffusion texture contouring artifacts which includes modifying the input pixel values for a fraction of the input pixels using a periodic dither signal, where the fraction is a function of the texture artifact characteristics of the multi-level error diffusion halftoning process.

Abstract: A method for obtaining a correction value including: forming a first test pattern configured to include a plurality of pixel rows, each of which has a plurality of pixels arrayed in a predetermined direction, arrayed in a direction crossing the predetermined direction; obtaining a first read gray-scale value for every pixel row by making a scanner read the first test pattern; calculating a first correction value for every pixel row on the basis of the first read gray-scale value; forming a second test pattern, which is configured to include the pixel rows arrayed in the crossing direction, using the first correction value; obtaining a second read gray-scale value for every pixel row by making the scanner read the second test pattern; calculating a correction amount for every pixel row on the basis of the first read gray-scale value and the second read gray-scale value; and calculating a second correction value of the certain pixel row on the basis of the correction amount of the pixel row and the correction a

Abstract: A line-based digital halftoning technique uses both a wavelet transform and multi-scale dot assignment concepts in which the dots are assigned in a top-down fashion and error diffusion is also adopted to fine tune the halftoned images and compensate for errors generated by the implicit quantization. 1-D processing makes the implementation easy while the top-down multiscale dot assignment can produce a multi-resolution halftoned image, which provides a good approximation of the original in multiple scales.

Abstract: Image processing apparatus and image processing method for formation of high quality image by high-speed error diffusion processing by execution of more complicated threshold condition processing in a simple manner. When error diffusion processing is performed on multivalued image data having plural density components and the result of processing is outputted, upon execution of error diffusion processing on a first density component among the plural density components, a threshold value used in the error diffusion processing is determined based on a density value of a second density component, then the error diffusion processing is performed on the first density component based on the determined threshold value, and the result of execution of the error diffusion processing is outputted.

Abstract: What is provided are a novel system, method, and computer program product for hierarchical (telescopic) color error diffusion which effectively controls the dot distribution for both primary and secondary dot formation which covers the class of error diffusion that follow telescopic dot firing constraint principles. In one example embodiment, an input CMYK ink coverage is received. The input CMYK ink coverage is transformed into a CMYKRGB domain using a CMYK to CMYKRGB conversion. A weighted error value can be added to each color component of the CMYKRGB domain. The color components of the CMYKRGB domain are hierarchically grouped into a plurality of subgroups based on relative dot visibility. More visible subgroups are half-toned earlier to achieve maximum uniform dot distribution. Dots of specific color channels within subgroups are fired based on thresholding and a set of decision rules provided herein.

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: A method for multi-toning an input digital image having input pixels with two or more color channels to form an output digital image having modified output levels. The method includes producing shifted error signals for each color channel, weighting the shifted error signals to determine weighted error signals for nearby pixels that have yet to be processed; producing shifted weighted error signals; and adjusting the input levels for the nearby pixels responsive to the shifted weighted error signals.

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: Methods and systems for performing threshold stamping are disclosed. A pixel intensity value for a first pixel may be determined. A pixel value for the first pixel may be retrieved from a memory location corresponding to the first pixel. A threshold delta value may then be determined based on the pixel value and added to a base threshold value to produce a threshold value. If the pixel intensity value exceeds the threshold value, a plurality of pixel values corresponding to a plurality of pixels may be updated. The plurality of pixels may include the first pixel and one or more second pixels. Otherwise, the pixel value for the first pixel may be updated.

Abstract: An image processing method and apparatus is provided that executes conversion processing of image data according to an error diffusion method. A unit processing for one pixel of the original image and another unit processing for an interpolate pixel that is inserted between lines of pixels of the original image are executed in the line direction. The processings for one line are sequentially repeated for each line of the original image. A calculating portion, for calculating an average error value which is an average of error values of a plurality of neighboring pixels, is utilized for converting a pixel value of a target pixel. A plurality of multiplying sections and addition memory sections are provided in correspondence with the alignment of a plurality of previous-line-neighboring pixels in a previous line located ahead of a pixel line in which the target pixel exists.

Abstract: A method for setting a boundary value at a level of error diffusion, comprising a step of defining a characteristic curve on a coordinate plane defined by a first axis indicating a perceptually uniform scale and a second axis indicating grayscale values of original data. The perceptually uniform scale is given by a normalized one of chromatic tristimulus values to the power of ?. A boundary value at a level of error diffusion is determined based on the characteristic curve and is stored in a storage device. The boundary value is read from the storage device for error diffusion processing, and error diffusion is performed on input image data using the read boundary value.

Abstract: Error diffusion is performed upon input image data. In one aspect, multiple error diffusion processing elements perform error diffusion on a selected pixel in parallel. In another aspect, the error diffusion logic is integrally formed with a fast local memory in the same electronic device, such as an ASIC. The error data produced by the error diffusion logic for a pixel is buffered in the fast local memory until it is to be used by the error diffusion logic on other pixels. In still another aspect, a first-in-first-out (FIFO) buffer regulates or buffers the color image data between the output of a color conversion system, such as a colorant lookup table, and the input an error diffusion processing element. In yet another aspect, the error diffusion logic has tagging logic that produces and stores an indicator, either in the output data stream itself or in a separate area, to indicate whether a raster contains printable data.

Abstract: A system for preparing documents for printing includes a stored object corresponding to an image having an effective resolution, as well as a computing device. The computing device is configured to receive an electronic file comprising data representing a plurality of embedded images wherein each embedded image has an effective resolution. The computing device determine whether an object associated with a first one of the embedded images is identical to the stored object. If so, it replaces the first one of the embedded images with the image corresponding to the stored object when the effective resolution of the first one of the embedded images and the effective resolution of the image corresponding to the stored object are within a preselected threshold.

Abstract: An image forming apparatus to connect a video controller to a laser scanning unit through a cable and the video controller includes a halftone table in order to perform a halftone process with respect to an original image. The halftone table includes a dot region having at least two shapes and a non-dot region.