Abstract: The invention provides a printing method of performing printing on a print medium. The method includes: generating dot data representing a status of dot formation on each of print pixels of a print image to be formed on the print medium, by performing a halftone process on image data representing a input tone value of each of pixels constituting an original image; generating the print image by combining forward pass dots with backward pass dots in a common printing area in such a manner that each main scan line includes both the forward pass dots and the backward pass dots, the forward pass dots being formed on a plurality of pixels of a first pixel group in a forward pass of main scan of a print head, the backward pass dots being formed on a plurality of pixels of a second pixel group in a backward pass of main scan of the print head.

Abstract: Disclosed herein is an image processing apparatus including: a screen processor for determining each pixel value of a screen processing application unit region composed of a plurality of pixels to which a threshold matrix is applied, in an inputted image; and for carrying out a screen processing by applying one threshold matrix among a plurality of threshold matrices in which applied positions of the threshold values are different from each other, to the plurality of pixels in the screen processing application unit region based on each determined pixel value.

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: Efficiently processing contone image data by determining one or more characteristics of the image data and using these characteristics to manipulate the dither matrix so that the printed image is enhanced.

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

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

Abstract: In an image forming apparatus includes a quantization threshold value to convert input image data of an N value to output image data of an M value based on random dither processing. A flag to designate addition of a non-periodic component to a quantization threshold value can be set for each quantization threshold value and a threshold value that has a non-periodic component is added to the quantization threshold value based on a relation between a large and a small quantization threshold value in different threshold value levels with respect to any target pixel in the quantization threshold value.

Abstract: A CPU generates a mask pattern by generating patterns corresponding to a predetermined number of times in the sub-scanning direction in accordance with the number of printing elements of a printhead which corresponds to the amount by which scanning is performed once in the sub-scanning direction, and repeating this operation by the number of times corresponding to a predetermined number of columns. The generated mask pattern is stored in an RAM. An image is then printed by using image data and the mask pattern stored in the RAM for each printing timing signal in the main scanning direction.

Abstract: A method and apparatus for printing a multivalue image in a binary-form output pattern. The printing apparatus employs a binary-form dither matrix pattern which is composed of a greater number of pixels, so that moiré patterns and other artifacts are minimized in printouts. The method includes: providing the binary-form dither matrix pattern for use in obtaining the binary-form output pattern; expanding the multivalue image in a memory area; and forming a binary image of output dot elements in accordance with the binary-form output pattern. The binary-form dither matrix pattern has a rectangular pattern in which a plurality of pattern elements that are numbered to be successively turned on are arranged in matrix. The turning-on sequence is set in such a way that plural groups of prospective output dot elements, which groups are substantially identical in shape, grow successively from a plurality of local points associated with the respective groups.

Abstract: In a halftone module, it is judged whether or not the value “rate” for each pixel is greater than zero (0). In other words, it is judged whether or not the eight-bit input data Iin of each pixel is around a half of the relative density value for a small dot of a corresponding color. If the eight-bit input data Iin of the subject pixel is near to a half of the relative density value for a small dot, noise is added to the threshold values Ta, Tb, and Tc. The noise-added threshold values Ta?, Tb?, and Tc? are used in the comparing process.

Abstract: In an image processing device and image processing method in which first image data consisting of a plurality of color data and constituting image information for each pixel are input, and second image data consisting of a plurality of color data are calculated and output, after color conversion of the first image data, dither processing is applied to produce the second image data. As a result, information of the fractional part generated as a result of the color conversion is not omitted but preserved. Tone conversion may be performed after the color conversion, and before the dither processing. The image processing device or image processing method can restrain reduction in the number of colors that can be expressed, and restrain the generation of discontinuities (irregularities) in the change of data, while realizing an “exact color reproduction” or “preferred color reproduction.

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: While a general large layer dither volume provides great flexibility in dither cell design, by decoupling different intensity levels, they are inefficient to access since each colour component requires the retrieval of a different bit from the volume. Therefore in a multi threshold dither volume for digital halftoning a contone colour image, in the form of an array of contone colour pixel values to bi-level dots, there is allocated for each dither cell location a fix set of n thresholds defining n+1 intensity intervals within which said dither cell location is defined to be alternatively not set and set.

Abstract: A method of building threshold matrices for stochastic screening by using the actual size and shape of imaged pixel and/or pixel agglomerate instead of the nominal one, in the stage of calculating appropriate threshold matrices. For each relevant combination of imager and imaged media, a matrix with desirable blue-noise-like characteristics is created from actual imaged pixels and/or pixel agglomerates, taking into account their overlap when placed in close proximity.

Abstract: A method for processing image data includes the step of dithering a contone layer of the image data. A black bi-level layer of the image data is composited over the contone layer. An infrared tag is rendered to an infrared layer of the image data.

Abstract: Methods, devices and systems for compressing images are provided. One method includes creating halftone mask structures and applying compression coding techniques to arrayed pixels sorted using the halftone mask structures in order to convert an image to a compressed bi-level, halftoned image.

Abstract: A method of screening a continuous tone image into a halftone representation for a flexographic printing operation can compensate for characteristic printing problems in highlight areas by selectively placing non-printing dots or pixels proximate highlight dots. The non-printing dots or pixels raise the printing relief floor in the highlight areas providing additional support for marginally printable image features.

Abstract: This invention has as its object to efficiently encode an image. To this end, for example, an image undergoes a color reduction process using a dither matrix with a predetermined size. A print control command is output. A compression parameter designation command that designates an up copy vertical offset value (a value according to the matrix size), a near left copy horizontal offset value (a value according to the matrix size), and a far left copy horizontal offset value (a value according to the period of background patterns), which are used in encoding, is output. Image data is encoded according to an encoding sequence.

Abstract: An input dither pattern determiner divides an input dither image to plural blocks, and determines an input dither pattern for each block. An output dither image portion converts the input dither pattern for each block to an output dither pattern. A reference emission time determiner portion determines a reference emission time for each block based on dark electric potential distribution and intermediate sensitivity distribution of a photoconductive drum, a light intensity distribution of a laser beam in a main scanning direction, and the output dither pattern. An area emission time calculator determines area emission time for each area based on a reference emission time for each block. An actual emission time calculator adjusts emission time for each area so that differences between reference emission times of blocks adjacent one another in the main scanning direction become a predetermined value or lower, and calculates actual emission time for each area.

Abstract: A method and apparatus for dithering for multi-toning are provided. The apparatus includes a mask-pattern-generating unit that generates a mask pattern on R channel, G channel and B channel by selecting pattern values constituting the mask pattern on the channels based on randomly-determined seed values; a spatial-weight-determining unit that determines the weight for spatial dithering by using the pattern values and K-bit LSB data of the high-tone input image; and an output unit that outputs an M-bit image by applying the weight to M-bit input image data, exempting the K-bit LSB data, in a dithering apparatus for expressing an M+K bit high-tone input image in an M-bit low-tone output device.

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

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

Abstract: Image data is encoded using a block consisting of a plurality of pixels as a unit of processing. A statistics section extracts statistical information for each pixel value, from a plurality of encoded blocks adjacent to an encoding target block, at each corresponding position within the respective blocks. An encoding processing section performs encoding on the encoding target block using the statistical information extracted by the statistics section. The encoding processing section comprises a prediction section that predicts a value of an encoding target pixel from the selected reference pixel based on the statistical information, a comparison section that detects an error between the predicted value and the value of the encoding target pixel, and an encoding section that performs entropy encoding on the prediction error.

Abstract: A superpattern generator uses a first halftone pattern representing a first gray level and a second halftone pattern representing a second gray level to generate a larger pattern or “superpattern”. In a preferred implementation, the superpattern generator generates a grid of elements to be used as a template for the superpattern, calculates a distance value representing the “distance” from the first gray level to a desired gray level TX, determines how many elements of the grid represent the first halftone pattern and how many represent the second halftone pattern based on the distance value, superimposes a dither matrix on the grid and assigns values representing the first halftone pattern or the second halftone pattern to pixels within the elements of the grid by examining threshold values in the dither matrix. This process is repeated for various values of TX to generate a set of superpatterns representing a set of gray levels intermediate to the first gray level and the second gray level.

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

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

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

Abstract: A method of printing a contone image in the form an array of contone color pixel values using a printer adapted to print bi-level dots. In the method comprising the contone image is dithered using a dithering volume, the dithering comprising assigning for each dither cell location a fixed set of n thresholds defining n+1 intensity intervals within which the dither cell location is defined to an alternative not set and set.

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

Abstract: An apparatus for forming an image includes a photosensitive body, an optical write unit which scans a light beam along a main scan path on a photosensitive body to create a latent image thereon, the light beam having power levels corresponding to multi-level image data, and a shading correction unit which corrects shading along the main scan path by making adjustment to the multi-level image data along the main scan path, and changes the adjustment on a condition-specific basis.

Abstract: There is disclosed a method of dynamic generation of a linearized halftone matrix from a high bit resolution halftone matrix, for use in a printer device, for example a domestic or office printer device or a commercial high resolution printer device. A high bit resolution halftone threshold matrix is converted into a vector format (700). A tone correction function is applied by selecting a variable number of index values, each index value representing a threshold level. A tone corrected two-dimensional 8 bit threshold level matrix, is then applied to a corresponding print image plane comprising a plurality of pixels to obtain a two dimensional print data for each of a plurality of colors of an image. The print data is printed as a plurality of dots by a print head to form a printed image using a halftoning method.

Abstract: While a general large layer dither volume provides great flexibility in dither cell design, by decoupling different intensity levels, they are inefficient to access since each color component requires the retrieval of a different bit from the volume. Therefore in a multi threshold dither volume for digital halftoning a contone color image, in the form of an array of contone color pixel values to bi-level dots, there is allocated for each dither cell location a fixed set of n thresholds defining n+1 intensity intervals within which said dither cell location is defined to be alternatively not set and set.

Abstract: An image formation apparatus includes an aperiodic data generating unit for generating aperiodic data between pixel areas having a neighboring relation every pixel area comprising a plurality of pixels having an interlocking relation of the image data, a threshold value deciding unit for converting the aperiodic data into a plurality of threshold data for forming a systematic dot array in the pixel area, and a gradation conversion processing unit for performing a gradation converting process by comparing the image data with the threshold data, thereby reducing a signal processing amount as compared with that in case of performing the propagating process on a pixel unit basis.

Abstract: A printer system comprises a communication interface and printer components. The communication interface receives a humidity value from a toner cartridge. The printer components control printing operation based on the humidity value. To control printing operation, the printer components may configure a dither matrix based on the humidity value. The toner cartridge comprises a humidity sensor and a communication interface. The humidity sensor detects a humidity level and generates the humidity value to correspond to the humidity level. The communication interface transfers the humidity value from the humidity sensor to the printer system.

Abstract: Noise adding unit 700 reads the downloaded target JPEG image from memory and adds designated noise to that JPEG image. Reverse DCT transformation unit 710 performs reverse discrete cosine transformation on the noise-added JPEG image, and transforms it from space frequency to spatial coordinates. Binarization unit 720 binarizes the image that has been expanded to spatial coordinates. This makes it possible to achieve the same processing as half-tone processing on images that have undergone normal orthogonal transformation without putting a large burden on the CPU, etc. and with a small data volume even when transferring via a communication path.

Abstract: A mask is produced for converting multi-level image data into a halftone image through comparison with a threshold for each pixel. For this purpose, a dot pattern is determined on each of predetermined gray scale levels, and, the mask is created by the dot patterns obtained at the step, where the respective dot patterns are determined independently for every gray scale level.

Abstract: It is necessary that paper be moved past the printhead at a constant velocity to obtain artifact-free printing. Therefore the printhead requires a constant stream of data during printing. Whilst it is possible to rasterize the page using a page description language directly to the printhead, it is uneconomical. Hence the redering is carried out in the PC. However, the standard USB peripheral connection is the standard connection on PCs, which places a constraint on the limit of data per page that can be transmitted to the printer and still obtain a reasonable rate of printing. Thus the contone images and graphics are rendered in the PC to a pixel level, and the black text and graphics are rendered in the PC to a dot level, where the rendered data is compressed and transmitted to the printer. The transmitted data is decompressed and combined and the images overlaid and printed.

Abstract: A system and method for effectively implementing a dither matrix for an electronic printer device may preferably create an improved dither matrix with optimal threshold values for use in a corresponding dither tile. During a matrix populating procedure for assigning tile threshold values for the dither matrix, the dither tile may preferably be embedded within a larger frame area of additional adjacent frame cells. A design entity may then preferably compute various cost functions when the additional boundary cells of the frame area are in place. The embedded dither matrix of the dither tile is thus preferably populated within the foregoing frame area so that various boundary effects may be taken into account when an overall cost function of both the dither tile plus the frame area is calculated.

Abstract: The invention provides a method and an apparatus for dithering, and inversely dithering an image. The apparatus makes use of a pixel address and a pixel data to locate a dither reference value from a dither matrix and use the dither reference value to convert an original pixel data having N bits into a dithered pixel data having M bits (N>M). On the other hand, the apparatus for performing an inversely dithering process makes use of the pixel address and the dithered pixel data (M bits) to locate a dither reference value from a dither matrix. Then, the dither reference value is employed to perform an inversely dithering process to recover the dithered pixel data into original pixel data.

Abstract: A method, apparatus and article of manufacture for providing improved print quality regardless of media smoothness is disclosed. Information regarding the smoothness of media is ascertained and the information about the media smoothness is used in the generation of an output. A selectable halftone screen is used in the print device to provide different halftone screens for different media smoothness. The halftoning screens can be changed depending on the roughness of the media being used. Pre-defined halftone screens may be stored and selected for a range of media smoothness. The selection of the pre-defined halftones may be selected by the operator or may be selected automatically by the print device.

Abstract: A display system provides stochastic dithering to image data for storage in a frame buffer for display. Dithering is used to reduce the size of the frame buffer and to reduce the complexity of the drive circuitry that is used to display an image. The bit depth of the frame buffer is reduced by spatially dithering image data before it is written into the frame buffer. Stochastic dither patterns (which are uncorrelated) are used to minimize adverse effects of the dither patterns within the displayed image.

Abstract: Apparatus and method 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. This flexibility in growing basic halftone patterns allows the number of densities output to be larger than n+1 (where “n” is the number of dots within a basic halftone cell).

Abstract: The invention provides a method and apparatus for the reproduction of color images by multi-color dithering. Multi-color dithering is an extension of bi-level dithering for halftoning an input image using as primary colors an arbitrary number of inks. The inks may comprise standard inks or non-standard inks such as non-process color inks, opaque inks, metallic inks, variable color inks and fluorescent inks. Multi-color dithering provides a solution for creating artistic multi-color dithered images, whose screen elements are made of artistic color screen shapes such as micro-letters, symbols and ornaments. When printed at high resolution and at high registration accuracy, multi-color dithering using large dither arrays incorporating artistic dither shapes provides an effective solution for preventing counterfeiting. The use of non-standard inks offers additional protection. Multi-color dithering also offers a solution for printers requiring that all inks are printed side by side, without overlaps.

Abstract: Systems and methods for optimizing the advantages of multi-level rendering of text and/or graphics at an output device by providing an alternate manner to perform multi-level rendering. A computer device, employed to render an image or graphical entity, is connected to an output device, and a request is received at the computer device to render a graphical entity at the output device. The resolution of the output device is identified and the data corresponding to graphical entity is translated to a resolution that is higher than the resolution of the output device. A conversion or translation is then performed to scale the image data from the higher resolution to the resolution of the output device. Optionally, a halftone matrix is employed to eliminate aliasing. The graphical entity is then more accurately rendered at the output device than by utilizing traditional techniques.

Abstract: Embodiments of the present invention relate to methods and systems for detection and delineation of text characters in images which may contain combinations of text and graphical content. Embodiments of the present invention employ intensity contrast edge detection methods and intensity gradient direction determination methods in conjunction with analyses of intensity curve geometry to determine the presence of text and verify text edge identification. These methods may be used to identify text in mixed-content images, to determine text character edges and to achieve other image processing purposes.

Abstract: A system and method corrects luminance non-uniformity caused by images being obliquely projected onto a screen. A camera is used to record the geometry of the obliquely displayed image. Utilizing this recorded geometry, a homography is then derived that maps pixels between the projector's coordinate system and the screen's coordinate system. Utilizing the homography, the projector pixel that attends to the largest projected area on the screen is identified. Next, the ratio of each pixel's projected area to the largest projected area is computed. These ratios are then organized into an attenuation array that is used to produce “corrected” luminance information from input image data. The projector is then driven with the “corrected” luminance information.

Abstract: This invention is a method of multilevel dither screening in a printer. Plural pixel values are packed into equal sections of a first data word. Corresponding dither values are packed into the equal sections of a second data word. These first and second data words are added in an arithmetic logic unit selectively spilt into the equal sections. Each section of the sum data word is saturated to all 1's. A predetermined number of least significant bits of the saturated sections are truncated. The resulting normalized pixel values are quantized into a limited set of threshold ranges. This dithering process serves to introduce an amount of scattering to the input pixel values to reduce quantization and pixelation artifacts in the final printed product.

Abstract: A non-periodic dot output arrangement is taken in the low thickness region, and a periodic dot output arrangement is taken in the intermediate and high thickness region. In addition, error diffusion processing is made for all thickness regions. Small dots are produced in the non-periodic dot arrangement low-thickness region, and dot-concentrated-type dots are produced in the periodic dot arrangement intermediate-and-high-thickness region. Moreover, non-periodic dots are produced in the edge region of the image.

Abstract: An inkjet printhead assembly is provided comprising an inkjet printhead and a print controller for controlling printing performed by the printhead. The print controller comprises an interface for receiving compressed page data, a decoder for decoding any infrared tags in the received compressed page data, a dot merger unit controlled by a color mask for mapping the decoded infrared tags into channels corresponding to what inks are supplied in the inkjet printhead, and a printhead driver for outputting the mapped infrared tags to the inkjet printhead.

Abstract: In one aspect of the present invention, a method is provided for producing a halftone of a source image. The halftone includes halftone pixels. The halftone pixels are suitable for containing halftone dots. The method selects glyphs corresponding to intensities of regions (e.g., pixels) in the source image. The glyphs contain one or more halftone dots. The method locates halftone dots within the halftone pixels such that for at least one pair of halftone dots contained within a pair of halftone pixels sharing a common boundary, the halftone dots in the pair of halftone pixels extend in opposite directions from the common boundary.