Abstract: A method of adjusting primary color data values including producing color saturation adjusted primary color data values that depend on a relative amount of chroma in the initial primary color data values.

Abstract: A scanner has an imaging device which is constituted by a cold-cathode tube, includes a light source for irradiating light to a reflection surface of a reference white plate and a plurality of pixels arranged in one line, and detects light reflected on the reflection surface by the respective pixels, and has a light source stability determination unit which determines whether or not light amounts obtained by the one line of pixels from the light source are approximately uniform. Only in a case where the light source stability determination unit determines that the light amounts obtained by the one line of pixels from the light source are approximately uniform, the scanner reads the reference white plate to calculate correction values for the respective pixels and reads a manuscript.

Abstract: An image forming apparatus adds a plurality of dots of image data in the subscanning direction and starts generating a density from a particular pixel, and switches PWM (Pulse Width Modulation) right and left phases in order to concentrate potentials and to increase a saturation region. It is therefore possible to stabilize image density in a highlight portion and therefore realize high quality images, while reducing banding and image noise.

Abstract: This disclosure describes image processing techniques that facilitate the determination of the lighting condition associated with an image. Once the lighting condition is determined, white balance can be performed on the image such as by applying white balance gains defined for the lighting condition. According to the techniques of this disclosure, gray point lines are defined and plotted for the different lighting conditions, and cylindrical bounding volumes are defined around the gray point lines, e.g., in a three-dimensional color space. The image is then analyzed with respect to each of the cylindrical bounding volumes to determine how many pixels of the image fall within the respective cylindrical bounding volumes formed around the gray point lines for the different lighting conditions. Based on this analysis, the actual lighting condition can be determined.

Abstract: An image processing device includes: a blank profile storing unit that stores data of a plurality of blank profiles; a threshold storing unit that stores a threshold matrix; a blank profile adding unit that generates blank added image data; a blank added binarization unit that binarizes the plurality of pixels of the blank added image data; a blank profile binarization unit that binarizes the plurality of cells of the blank profile; an output image generation unit that generates output binary image data; and an image output unit that outputs the output binary image data.

Abstract: To provide a reproduction method for printing wherein characteristic data of an original are transformed into data required for printing, with the dot gain being controllable so as to yield optimum reproduction results in the print, it is proposed that a modified characteristic curve of printing which in relation to the ideal characteristic curve of printing has a maximum above an area coverage of 50% be predefined for the transformation of the data in order to control the dot gain in printing.

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

Abstract: An image data of M-gradations in a pixel is converted into multivalued image data of N-gradations (M>N>2) in a pixel. A remarked pixel converted into the multivalued data is determined whether to be a predetermined gradation TJ (N>TJ>2) in which a tone jump occurs. When the remarked pixel converted into the multivalued data is determined to be the predetermined gradation TJ, it is determined whether a pixel of the predetermined gradation TJ exists in pixels being adjacent to the remarked pixel. When the pixel of the predetermined gradation exists, the gradation of the remarked pixel is changed to the gradation other than the predetermined gradation so as to prevent the tone jump, and an average density after multivalued image data conversion is preserved.

Abstract: Multivalued image information is input, subjected to multivalued processing, and converted into data representing the number of print dots for each pixel. Print dots are counted for each region made up of a plurality of pixels, and a print dot layout in a region of interest is determined in accordance with the count value of print dots in a peripheral region around the region of interest. This arrangement can provide an image processing apparatus and method capable of obtaining a high-quality image without increasing the amount of information.

Abstract: The present invention reduces the granularity of the dots for the entire density range by optimally setting formation amounts of a low-density dot and of a high-density dot per unit area. For this purpose, the formation amounts of the low-density dot and of the high-density dot in accordance with the density level are determined in such a way that as the density level rises, the formation amount of the low-density dot is gradually increased up to a first peak amount (200%) and, after reaching the first peak, gradually decreased, and in a range of density levels higher than a predetermined density level at which the low-density dot is formed to a specified amount (200%), as the density level rises, the formation amount of the high-density dot is gradually increased up to a second peak amount (100%) smaller than the first peak amount.

Abstract: A method is provided for creating a binary-coding pattern to be used in binary-coding a multi-value image. The method includes the steps of: creating a basic pattern shape of the prospective binary-coding pattern by a first arithmetic operation; determining the sequence of lighting pixels composing such basic pattern by a second arithmetic operation; and creating a rectangular pattern, which serves as the prospective binary-coding pattern, based on the resultant basic pattern. Hereby, it is possible to automatically create a centralized type of binary-coding pattern, and also it is possible to facilitate creating a minimum-sized binary-coding pattern.

Abstract: A method and apparatus for adjusting a printer is disclosed. An area is printed over, and sensors are used to collect pixel values over the area. Then, metric criteria are applied against pixel values to determine whether or not to adjust the number-density of dots to improve print quality. The apparatus includes a print means, sensor, and processor. It may also include storage to store the pixel values.

Abstract: After a gray scale image extracting unit converts an input document image to a gray scale image, a multi-code image binary-coding unit converts the image to a binary image having a value in which each pixel indicates either a background area or a plotting area in the image, and outputs the binary image to a binary image recognizing unit. In the multi-code binary-coding unit, a partial area extracting unit extracts one or more partial areas in the gray scale image. A partial image binary-coding unit executes a binary-coding process for each of the partial areas in the gray scale image. A binary image combining unit combines one or more partial binary images and constitutes a binary image of the entire gray scale image.

Abstract: An apparatus and method are provided to equalize a histogram using a cumulative distribution function (CDF) of an image. A model parameter estimator estimates parameters from the image using a Gaussian model. An error function storing unit stores error function values based on a Gaussian distribution. A CDF calculator calculates a CDF using one of the error function values from the error function storing unit and the estimated parameters. A histogram equalizer performs histogram equalization using the CDF.

Abstract: The data required to specify an image which is to be printed by a printing device, such as an ink-jet or laser printer, can be substantially reduced by omitting the data specifying the dot size or amplitude modulation (AM). Instead, the processor of the printing device determines the dot density in the immediate vicinity of each dot and, from that density measurement, calculates the appropriate dot size and modulates the dot size accordingly when driving the print head or print laser.

Abstract: Disclosed is a method, system, and program for reducing toner in an image comprised of raster pel data. A determination is made of pels surrounding subject pels. For each subject pel, a sub-pulse width power is generated to charge a sub-pel region within the subject pel based on a pattern of the surrounding pels of the subject pel. Further, for each subject pel, position information is generated indicating an alignment of the sub-pel region in the pel. The position information is used to position the sub-pel region produced by the sub-pulse width power in the pel.

Abstract: Tone jumps are eliminated in all areas ranging from a highlight area through an intermediate tone area to a shadow area for thereby achieving a smoother tone reproduction. Halftone dots are grown in a circular shape from a halftone percentage of 0% to a first highlight percentage. Halftone dots are grown while changing from the circular shape to a square shape from the first highlight percentage to a second highlight percentage greater than the first highlight percentage. Halftone dots are grown in a square shape from the second highlight percentage to a second shadow percentage. Halftone dots are grown while changing from the square shape to a circular shape from the second shadow percentage to a first shadow percentage greater than the second shadow percentage. Halftone dots are grown in a circular shape from the first shadow percentage to a percentage of 100%.

Abstract: Printing on an area of a printing medium in which printing locations may be significantly deviated due to inaccurate feeding of the printing medium can be performed, without degrading image quality. Specifically, when lines in this area (second area) are printed using four scanning operations (passes) of a print head, a duty in masking process is set at zero for the scanning operation (pass A) after a change-line operation for feeding the printing medium with a possible large shift feeding error, and is distributed to other scanning operations. Thus, no dots are formed during this scanning operation (pass A), thereby preventing significantly deviated dots from being formed.

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: A printer-system for printing or recording images using a plurality of dots having different densities. The printer system includes a head for producing at least 2 different types of dots having different densities per unit area, an input unit for receiving input tone data with respect to each of the pixels in an original image, a threshold value storage unit for storing threshold values, a multi-valuing unit for determining the on-off state of a dot and the type of the dot to be created at each pixel, and a dot creation unit for driving the printer head. Print image quality is degraded for example when, around any specific input tone value, there are abrupt changes in the number density of large dots to small dots. The multi-valuing unit, employing error diffusion techniques, changes the threshold values for selecting the type of dot printed to control the relative density of large dots at each input tone value and thus regulates the print image quality.

Abstract: A system for rendering an image representation is disclosed. The system includes a halftone processor; a printer interfaced to the halftone processor; and a software routine operative on the halftone processor for a) classifying an input pixel value in either a first classification or a second classification, b) determining an output pixel value by error diffusing the input pixel value when the input pixel value is classified in the first classification, c) determining a temporary output pixel value by stochastic screening the input pixel value when the input pixel value is classified in the second classification, d) determining an adjusted input pixel value based on the input pixel value, the temporary output pixel value and a weighting value, e) determining the output pixel value by error diffusing the adjusted input pixel value, and f) rendering the output pixel value in the printer.

Abstract: Halftoning by error diffusion, enhanced so as to reduce the presence of structural artifacts in the halftoned output while avoiding an artificial increase in halftoning image noise. Specifically, error diffusion according to the invention divides the input gray level intensity range into different segments for purposes of both thresholding and error diffusion. Different error diffusion threshold masks are applied for each respective segment, and different error diffusion weights are applied for each respective segment, with a decision being made as to whether or not to apply a different threshold mask being based on the local image gradient.

Abstract: An 8-bit (256 gradient) image is represented using a driver IC of 6-bit (64 gradient) construction to drive a plurality of arrayed optical shutter elements. The image data are divided into 64 gradient sections, synchronized by shift clock signals, and transmitted in four cycles to the shift register. The optical shutter element is not turned OFF at the 64th pulse, but is continuously driven without transmitting to the comparator the standard clock signal of the 64th pulse, which controls the ON time of the optical shutter element. In this way, an image of a higher number of gradient levels can be represented using a driver IC of a low number of bits, thereby providing a solid state scanning type optical recording device which suppresses noise generation by reducing the load on the driver IC when driving at multi-level gradient.

Abstract: In an image processing method, on the basis of input image data with respect to a target pixel, independent multi-level data (g0, g1) corresponding to respective plural species of dots which are different in at least one of a density and a diameter are generated, and then data (O0, O1) relating to an amount of generation of the dots with respect to the target pixel are generated on the basis of a relationship between the generated independent multi-level data (g0, g1) corresponding to the plural species of dots. The image processing method is effective in performing design having a high degree of flexibility in proper use of a relatively high power dot (high density dot or large dot) and a relatively low power dot (low density dot or small dot) and can realize obviation or alleviation of an occurrence of granulation or an apparent frame caused due to the relatively high power dot.

Abstract: A registration system for image data in a binary image path includes a registration parameter source, such as a preprogrammed memory or a dynamic device, which provides registration parameters to correct for registration errors from a predetermined reference likely or predicted to occur during image output. A warping processor is in data communication with the registration parameter source which applies a selected registration parameter to an element of the image data resulting in a warped data element, minimizing the effects of the registration error. The system optionally includes an image reducing device which receives groups of high addressable binary image data and converts them to a single pixel. The pixel is then provided to the warping processor. The warping processor applies the selected registration parameter, either static or dynamically selected, from the registration parameter source to the averaged single pixel producing a warped data element.

Abstract: A novel image forming apparatus which makes gray-scale by performing at least one of operations including a manipulation of a plurality of dots arranged in a form of matrix, a single-dot-based density adjustment, or a single-dot-based size adjustment, includes a dot status detector and a density adjuster. The dot status detector detects an occurrence in which a dot exists at a focus dot position and no dot exists at positions immediately adjacent to the focus dot position in the main scanning direction. The density adjuster adjusts a writing level of the dot at the focus dot position so as to make the gray-scale smooth when the dot status detector detects the occurrence.

Abstract: Input gray-scale bit map information is inputted to an image forming position extracting unit for extracting image forming position information. An input computer-formed image is inputted to an image forming position extracting unit for generating an image forming position. At an image forming position overlapping unit, two image forming positions are overlapped with each other, and the composed image forming position is sent to a pixel value calculating unit and an image forming position determining unit. The image value calculating unit measures a width of the composed image forming position and converts the measured value into a pixel value. The image forming position determining unit calculates a barycenter of the composed image forming position. The pixel value and the barycenter are sent as image information. Encoding without distortion can be executed by enhancing the precision of the barycenter.

Abstract: An image forming apparatus adds a plurality of dots of image date in the subscanning direction and starts generating a density from a particular pixel, and switches PWM (Pulse Width Modulation) right and left phases in order to concentrate potentials and to increase a saturation region. It is therefore possible to stabilize image density in a highlight portion and therefore realize high quality images, while reducing banding and image noise.

Abstract: A method for printing images using light black ink. The method sets a first and second threshold determined by an intensity value of the light black ink relative to standard black ink. The method then determines a gray component density value for a pixel, calculates a black generation value based upon the first and second thresholds and then generates values for other colors dependent upon the black generation value.

Abstract: A method for calibrating image recording equipment is described. According to the method, raster areas such as images or color prints are recorded pixel by pixel, line by line in the form of screen dots on an image support by use of at least one exposure beam generated in an exposure unit. An image stored as a bit-map image and containing line data (binary image) is divided into fields. A raster percentage is determined for every field by calculating an average. A variation in the raster percentage is determined from a density-exposure curve. The parameters required for the variation are calculated by an algorithm and memorized in a variation table. The most suitable algorithm is read from the variation table and executed and the data determined thereby are memorized.

Abstract: In a moire fringes eliminating apparatus, a moire fringe eliminating unit comprises a halftone dot feature extracting unit, a re-calculation unit, a re-calculation deciding unit, and a halftone dot shape changing unit. The halftone dot feature extracting unit extracts features of the halftone dots. The re-calculation unit obtains a re-calculation deciding value which represents a ratio between a total number of the halftone dots in a neighboring area and the number of the halftone dots having a similarity of feature being smaller than a predetermined threshold value in the neighboring area. The re-calculation deciding unit decides whether the threshold value should be changed in order to decide necessity of change of the number of dots based on the re-calculation deciding value.

Abstract: The reproduced image quality of a shuttle scanner is enhanced by automatically compensating for the scanner's assembly tolerances, using a method for correcting vertical alignment error in a shuttle scanner. The method includes the steps of: (a) initializing a block count of a document to be scanned to a value of N; (b) scanning the Nth block and rasterizing the scanned block into a dot image; (c) shifting each dot of the dot image formed by the rasterized block according to a set of pre-stored correction values; and (d) incrementing the block count and performing the steps (b) through (d) until reaching the end of the document being scanned. The set of pre-stored correction values is produced by the steps of: scanning at least one block of a reference pattern formed on the document to be scanned; comparing the scanned reference pattern with an ideal reference line to calculate a shift value for each dot of the scanned at least one block; and storing the calculated shift values in a memory device.

Abstract: A tape printer is presented to improve the print quality of a border portion between print areas. Dots, which are smaller in area than dots printed in a previous print area, are printed after being shifted by &agr; (1.0 dot) in the X direction from dots printed in an overlap area. Accordingly, even if the dots are printed slightly out of position, high-density overlap portions, where dots overlap with each other, and/or paper surface-exposed portions, where dots are away from each other, are not produced greatly or distributed unevenly.

Abstract: A system and method converts color data to gray data by allowing target values to be set for the color components and combinations of the color components to provide high quality gray data output.

Abstract: A method for binarizing an image that includes initializing, for each column of the image, a first set of variables representing a local column low pixel value and a local column high pixel value, and, for each row of the image, a second set of variables representing a local row low pixel value and a local row high pixel value. The following steps are iterated for each pixel: determining a threshold value dependent upon the first and second sets of variables at the current pixel location, comparing a value representative of an image pixel at the current pixel location with the determined threshold value, and setting a binarization pixel for the current pixel location to one of two values, dependent upon results of the comparison, and adjusting values included in the first set of variables and the second set of variables dependent upon the results of the comparison.

Abstract: The apparatus for displaying plasma display panel (PDP) gray scales includes an automatic power controller for detecting an average signal level (ASL) in each field of video data; first and second frame memories for storing the video data in even and odd frames; a sub-field generator for mapping the video data according to the number of sub-fields, generating gray scale data, and selectively storing them in the frame memories; an address data generator for generating address data and applying them to the PDP; an ASL controller for comparing the numbers of sub-fields in each field with each other, and controlling the number of sub-fields; and a sustain scan pulse generator for receiving the number of sub-fields, generating sustain pulses and scan pulses, and applying them to the PDP.

Abstract: When pixels in a two-dimensional matrix are divided into lines A and B in the column (or row) direction (sub-scanning direction) and two neighboring pixels in the row (or column) direction are subjected to gradation correction respectively using characteristic curves for lines A and B, the characteristic curve for line B unpreferably has a stepwise characteristic portion having a step when it is stored in an LUT, due to quantization errors unique to digital values. Hence, the characteristic curve for line A is set to be decreased by the amount corresponding to the step.

Abstract: A hyperacuity printing system for rendering bitmapped image data on a photosensitive recording medium, the bitmapped image data being rendered as an array of pixels across the photosensitive recording medium in a fastscan direction, and an orthogonal slowscan direction. This system includes a data source for supplying grayscale input image data and a scanning device for rendering grayscale output image data onto the recording medium. The scanning device has a device for writing scan spots on the recording medium. Further included in this system is transformation circuitry for transforming the grayscale input image data into grayscale output image data. The transformation circuitry includes a halftoner, a thresholder, and a selection device, where the selection device selects either the thresholder or the halftoner to provide the grayscale output image data.

Abstract: An image forming apparatus having first and second basic cells each containing a predetermined number of cells in a main scanning direction and a sub-scanning direction and disposed adjacent to each other in the sub-scanning direction, a gradation processing portion arranged to perform a gradation expressing process for each basic cell in accordance with a density of a supplied image and a dot forming portion capable of forming dots on a recording medium to correspond to each pixel subjected to the gradation expressing process by the gradation processing portion. The gradation processing portion performs the gradation expressing process in such a manner that enlargement of dots in the first and second basic cells adjacent to each other in the sub-scanning direction is inhibited in the sub-scanning direction until the dots are enlarged and connected to each other in the main scanning direction.

Abstract: A digital image processing apparatus is disclosed. The apparatus increases input pixel intensity values in an edge region of input image data to form output pixel intensity values. The input pixel intensity values are varyingly increased depending on a location of the input pixel values within the edge region. The output values are printed on an edge region of a print sheet. A printer prints the output intensity pixel values on a print sheet. The invention allows printing of digital images to the edge of a print sheet without accumulating a great deal of toner at the edge of the sheet or overburdening a toner cleaning device.

Abstract: A method and apparatus for adjusting a printer is disclosed. An area is printed over, and sensors are used to collect pixel values over the area. Then, metric criteria are applied against pixel values to determine whether or not to adjust the number-density of dots to improve print quality. The apparatus includes a print means, sensor, and processor. It may also include storage to store the pixel values.

Abstract: An electrophotographic image forming apparatus uses a halftone spot consisting of multiple dot images formed in pixel areas so as to represent a gray scale and to reproduce an image. It has a halftone processor for generating image reproduction data for each pixel by referring to a transformation table wherein gray level data for the image and correlated image reproduction data are stored.