Abstract: If gamut mapping (hue restoration) defined by one Lab color space is applied in color matching under different reference white points, the human vision perceives the hue as inconsistent. In view of this, input data which is dependent on a color space of an input device is converted by the conversion LUT 11 to color space data which is independent of any devices, based on a viewing condition at the time of viewing an input original. The data is converted to data in the human color perception space by the forward converter 12, then subjected to gamut mapping, and converted back to data in the color space independent of any devices by the inverse converter 15, based on a viewing condition at the time of viewing an output original. Then, the data is converted to output data in a color space which is dependent on an output device by the conversion LUT 16.

Abstract: An adaptive image tone mapping curve based on perceptual preference guidelines is generated as a sigmoidal function, in which the sigmoidal function parameters (slope and shift) are determined by original image statistics. Tone curves generated for different images each have a smooth sigmoidal shape, so that the tone mapping process does not change the image histogram shape drastically. The sigmoidal function has the form: t ? ( x ) = 100 1 + exp ? ( - ? ? ( x / 100 - ? ) ) , where ? is the slope parameter and ? is the shift parameter. The input value x in the sigmoidal function varies in the range [0, 100], because the tone curve is generated on an L* scale, which has values from 0 to 100.

Abstract: A bistable electro-optic display has a plurality of pixels, each of which is capable of displaying at least three gray levels. The display is driven by a method comprising: storing a look-up table containing data representing the impulses necessary to convert an initial gray level to a final gray level; storing data representing at least an initial state of each pixel of the display; receiving an input signal representing a desired final state of at least one pixel of the display; and generating an output signal representing the impulse necessary to convert the initial state of said one pixel to the desired final state thereof, as determined from said look-up table. The invention also provides a method for reducing the remnant voltage of an electro-optic display.

Abstract: A method of producing from a first device-dependent image data set, a second image data set matched to a real process, includes, by using inverse gamut mapping, transforming color values from the first image data set into color values of a device-independent color space and, by using gamut mapping, transforming these device-independent color values into the second image data set of an output device; and a color management method including the producing method.

Abstract: A driving method for a color liquid crystal display which drives the color liquid crystal display based on a video red signal, a video green signal and a video blue signal by independently applying a gamma compensation to a clamped video red signal, a clamped video green signal and a clamped video blue signal in gamma compensating circuits in order to make suitable to a red transmittance characteristic, a green transmittance characteristic and a blue transmittance characteristic. With this operation, it is possible to carry out an optimal gamma compensation suitable to a characteristic of the color liquid crystal display and to remove a gradation batter occurring in a specific color.

Abstract: An area separating apparatus for judging whether or not each object pixel belongs to a photograph image area in an image.

Abstract: Graphics processing circuitry includes processing circuitry operative to generate pixel information in response to primitive information, and a correction circuit, coupled to the processing circuitry, operative to generate gamma corrected pixel information in response to the pixel information. The correction circuit converts the floating point pixel information generated by the processing circuitry into a gamma corrected fixed-point value so that gamma space pixel data is stored in the frame buffer. This fixed point gamma corrected pixel information, converted from the floating point pixel information, compensates for the non-linear display characteristics exhibited by current display devices. This results in the display output being more accurate; thereby, improving the appearance quality of the resulting image.

Abstract: A construction is achieved at low cost which reduces the loss of gradation in a dark portion of an image that has been subjected to gamma correction in accordance with characteristics of a display. In an image reading apparatus, to make it possible to more finely reproduce the gradation in the dark portion, the number of gradations expressed by an signal obtained by a CCD is reduced by performing non-linear gamma correction using a gamma coefficient below one, and the resulting signal is transferred to a computer serving as a host computer. In the computer, the transferred signal is subjected to gamma correction using a gamma coefficient that is an inverse of the gamma coefficient used in the image reading apparatus, thereby canceling out the influence of the gamma correction performed in the image reading apparatus.

Abstract: In a receiver computer 100, a transmission controller 111 transmits user interface data 171 to a transmitter computer 200. In the transmitter computer 200, a display processing unit 213 causes a user interface for inputting print settings information to be displayed on the screen of a monitor 250, based on the transmitted user interface data 171. When the print settings information is input via an input device 240, a transmission controller 211 transmits color image data 271, color-correction source data 272, and the input print settings information to the receiver computer 100. In the receiver computer 100, a print processing unit 114 carries out a variety of processing operations with respect to color image data, based on the print settings information. A color correction element 118 in the print processing unit 114 carries out a color correction of the color image data using the color-correction source data 272 and color-correction destination data 172 read from a hard disk 170.

Abstract: A system and method for detecting text edges in digital document images utilizes filters that process the luminance and/or chrominance values within a selected region of the image to determine whether a given pixel of the selected image region is a text edge. The filters are configured to determine the gradient, the curvature, the maximum luminance value, and/or the maximum chrominance value for the luminance values within the selected region of the document image. Two or more of these indicators are used to detect text edges in the document image.

Abstract: Changes in the degree of contour correction in accordance with luminance signal level differences in image processing are adjusted to be visually preferable. Gamma correction is performed by a gamma correction circuit (106) with respect to an intermediate image signal in which an edge signal is added to an original image signal. Meanwhile, gamma correction is performed by a gamma correction circuit (108) with respect to an intermediate image signal in which the edge signal is subtracted from the original image signal. These two intermediate image signals are subtracted from each other by a subtracter (110) and the output thereof is added as an aperture signal to the original image signal that is output from a Y signal gamma correction circuit (54).

Abstract: The invention provides an image forming apparatus and an image forming method, capable of providing an image with little deterioration, even in case the image contrast has to be adjusted not for the purpose of image adjustment, such as for reducing the toner consumption amount or for preventing the leak in the charging device.

Abstract: A color reproduction system includes a tristimulus value calculation unit for calculating tristimulus values (X, Y, Z) under observation illumination light corresponding to the spectral reflectance of an object, which is obtained by a spectral reflectance calculation unit, and a color image signal calculation unit for calculating output color image signals (R?, G?, B?) to a CRT monitor on the basis of the tristimulus values (X, Y, Z). The tristimulus value calculation unit converts spectral reflectance image data (F) of the object into tristimulus value image data (X, Y, Z) under the observation illumination light using the spectral reflectance data of a color chip formed from a plurality of unit color chips, color chip image data (P?) obtained by sensing the color chip with a digital camera under the observation illumination light, spectral sensitivity data of the digital camera, and color matching function data.

Abstract: In a recording device, electrostatic recording units of Y, M, C and K are arranged along the direction of the feed of a recording sheet by a belt unit. The device forms latent images corresponding to image data by optical scanning of an exposure device onto a rotating photosensitive drum, develops the latent images with toner components having different colors, and then transfers the developed images onto the recording sheet on the belt unit. A color matching processing unit performs color matching processing including color slippage correction of different color images. An automatic color matching mode processing unit works the color matching processing unit when conditions beforehand decided in the state that an automatic correction mode is set up are realized.

Abstract: An image-processing method for performing color matching using a source profile and an output profile, includes a step of correcting input image data, a step of calculating a feature quantity of an input image based on the corrected image data, a step of performing an image correction process on the input image data in accordance with a processing condition responsive to the feature quantity, and a step of performing a color matching process on the corrected input image data. The image-processing method is thus performed with the color matching process result taken into account.

Abstract: A fast gamma correction method for an image reading apparatus is proposed. The original intervals for normalized output data are combined to merged intervals fewer in number and the original color correction function is replaced by a fitting function in the merged intervals. For an input normalized data, the corresponding merged interval is found and a fitting function associated with the merged interval is invoked to find the corresponding normalized and corrected data.

Abstract: This invention is a computer implemented method of approximating a gray scale tone with a more limited range image producer. One of a plurality of tone curves is associated with each pixel of a screening matrix. The plural tone curves are approximated by a polynomial and the polynominal coefficients are determined. The polynomial coefficients are stored in a look-up table. Each pixel of an image is mapped to a corresponding pixel of the screening matrix. For each pixel the corresponding polynomial coefficients approximating the tone curve are recalled and used to compute a pixel output value from a pixel input value. The polynomial is preferrably of the third degree polynomial and in a form easily computed using a digital signal processor with a hardware multiplier and arithmetic logic unit. Screening in this manner requires less memory storing the screening data than the prior art pure look-up table screening.

Abstract: A method and system for determining a transition model between input pixel samples from which output sample values are calculated based on various relative background and brightness conditions of the input pixel samples. A brightness condition is determined from the input sample values associated with the input pixel samples. A first transition model that preserves a constant luminance is used where the brightness condition is indicative of light isolated pixels and a second transition model that preserves a constant darkness is used where the brightness condition is indicative of dark isolated pixels. The resampling circuit may also use alternative models for other brightness conditions, such as for pixel transitions without any emphasis or alternating pixels. The resampling circuit may also perform modified operations for pixels arranged in a diagonal fashion.

Abstract: A method of adjusting the balance of a digital image including a plurality of pixel values inverts the pixel values and applies a gamma value (?) individually to each inverted pixel value to raise each inverted pixel value to the power of the gamma value. The gamma value is related to an exposure adjustment amount (A) indicating a desired exposure adjustment of the original scene. Then the inverted pixel values are themselves inverted after application of the gamma value, thereby providing modified pixel values representative of a modified digital image that is adjusted for exposure.

Abstract: A first reference image as a natural image is displayed on a display, and a first test image including the first reference image and a plurality of first modulated images each obtained by slightly modulating colors of the first reference image is printed. The first modulated image having color tones closest to the first reference image displayed on the display is selected by the operator, and global color correction in a color space is performed on the basis of the first reference image and the selected first modulated image. Further, a second reference image of a single color is also displayed on the display, a second test image including second modulated images is printed, one of the second modulated images is selected, and local color correction in the color space is performed on the basis of the second reference image and the selected second modulated image.

Abstract: In order to accurately correct environmental variation and aged variation of gamma characteristics, RGB tone data are color-converted to be formed as CMYK tone data, then a tone correction for improving gamma characteristics is performed on the CMYK tone data. The CMYK tone data after the tone correction are subjected to half-toning to be converted into half-tone data. On the basis of the half-tone data, an image is printed by an electrophotography process. A test image is printed at a predetermined timing. A sensor reads the test image. On the basis of a signal of the sensor, a correction table for the tone correction is calculated by correction table calculation. In the tone correction, 8-bit input tone data are converted into 10-bit corrected tone data. Since the tone correction is performed on CMYK data in place of RGB data and the bit number of tone data is extended from 8 bits to 10 bits by the tone correction, the accuracy of improvement of gamma characteristics is enhanced.

Abstract: An apparatus, a method and a system for image processing with a color correction device are provided in which the number of times of automatic execution of calibration is reduced and the performance of an image output apparatus is used adequately. The apparatus includes a color space conversion portion 110 for converting input image data D1 into data D1s of a standard color space and a reproduction range decision portion 111 for deciding whether the input image data D1s that were converted into the standard color space are within a reference range of a color reproduction in an image output. If it is decided that the input image data are out of the reference range, the calibration is performed so that the color reproduction range is made close to the reference range.

Abstract: The present invention provides a technique for modeling the tone reproduction curve of a flat panel screen such as an LCD. The technique employs a second order function to predict the luminance output as a function of the input voltage based upon two known input values. This abstract is provided for the sole purpose of complying with the rules requiring an abstract to allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure contained herein. This abstract is submitted with the express understanding that it will not be used to interpret or to limit the scope or the meaning of the claims.

Abstract: A facsimile apparatus, a computer-readable program, and a storage medium are disclosed. The facsimile apparatus is equipped with a reader for reading original image data, a communication interface for transmitting the read image data to a predetermined network and receiving image data from the network, and a printer engine for forming an image on a medium based on the received image data. The facsimile apparatus further includes storing means for storing the image data in a first data format; receiving means for receiving a request that the image data be sent to a predetermined transmission destination; data format conversion means for converting the stored image data from the first data format into a second data format; and transmitting means for transmitting the converted image data to the requested transmission destination.

Abstract: An image processing apparatus has a first information addition unit configured to add to image data information related to image processing of the image data according to a first addition method as first information, and a second information addition unit configured to add the information to the image data according to a second addition method different from the first information addition method as second information. At least one of the first and the second information added is not lost even when an image processing is performed with respect to the image data.

Abstract: The method of the invention converts colors resident in a first device color space to gray levels for reproduction by a single color marking media in a color or monochrome rendering device. The method converts a set of red, green and blue (RGB) primary color values received from a processor to gray level values. The method applies a gamma correction function to the RGB primary color values and further scales the values to a range of from 0 to 1. The method then converts the gamma-corrected and scaled RGB primary color values to a Y luminance value (in the XYZ tristimulus color space) through use of the expression: Y=YR(R)+(YG−kG)(G)+(YB+kB)(B) where: YR, YG, and YB are coefficients that provide a luminance value in the XYZ color space in accordance with accepted observer standards; kG is a correction value that renders the green component darker; and kB is a correction value that renders lighter the blue component.

Abstract: A color correction filtering system filters color video data by compensating for non-linearities and color characteristics specific to a color monitor. Color video data is received by the system, for example through a web browser, and in an accelerated manner passed through a pre-calculated gamut-shifting array. The color correction filtering system gamma decompensates incoming color video data referenced to a non-linear color space through use of a linearization filter. The gamut-shifting array may contain pre-calculated compensation values stored in a plurality of look-up tables. A non-linearization filter is applied to the gamut-shifted color video data to produce color video data compensated for non-linearities specific to the color monitor.

Abstract: An input image represented by a set of input pixel values is color-corrected by locally modifying the input pixel values according to pixel neighborhoods; and determining an output image having a set of output pixel values. Each set of output pixel values equals a non-linear combination of a set of input pixel values and its corresponding set of modified pixel values.

Abstract: The present invention relates to an image processing method, apparatus and computer program for improving an image sensed by an image sensing apparatus and processed according to a first conversion process. The present invention involves determining whether or not the first conversion process includes a nonlinear conversion, processing the image according to a second conversion process inverse to the first conversion process if the first conversion process includes the nonlinear conversion, and processing the image processed according to the second conversion process, according to a function for improving the image.

Abstract: In an image forming apparatus having a particular area setting unit for setting an arbitrary area of a document image as a particular area, an image processing unit (scanner/IPU section) receives, when a particular area is specified, image data for the particular area, and generates a plurality of monitor image data having been subjected to image processing by setting a different image quality mode for each particular area, and further an image forming unit (printer section) receives the plurality of monitor image data and forms a plurality of monitor images on the same transfer material by arranging the monitor images at different positions on the transfer material.

Abstract: An apparatus for printing a color image includes a printer driver which processes input image data to generate printable image data, and further includes one or more color profiles which are used by the printer driver to perform color matching on the input image data in a normal mode, wherein the printer driver uses one or more toner-saving-purpose profiles to perform color matching on the input image data in a toner saving mode, the one or more toner-saving-purpose profiles being specifically designed to reduce a toner amount on a printed color image.

Abstract: The invention is directed towards method and apparatus for performing local color correction. One embodiment of the invention is a two-part process. The first part derives an image mask from an input image. In some embodiments, the mask is an inverted, low-pass filtered, monochrome version of the input image. The second part combines the derived mask with the input image through a non-linear operation. In some embodiments, the combination operation is a variable exponential function that has the mask values as part of its exponent and the pixel values as part of its base.

Abstract: An image capturing apparatus capable of performing a suitable illuminance nonuniformity correction by setting a suitable &ggr;-characteristic every block even in the case that the size of a character image projected on a sensing surface changes according to an image capturing magnification, and capable of extracting a boundary area between a white board portion and a background portion and applying a suitable image processing to this boundary area during the illuminance nonuniformity correction for a picked image, and capable of image capturing a representation such as characters drawn on a white board in such a manner that an obtained image is clear and easy to see by suitably performing an illuminance nonuniformity correction even in the case of color image capturing, and capable of detecting a regularly reflected light with high accuracy and can thereby securely prevent an error of obtaining an image of low quality by image capturing, and capable of preventing an error in flash-image capturing a representa

Abstract: Methods and apparatuses, including computer program products for generating a plurality of color processing module fingerprints are described. A set of input colors represented in an input color space is generated. Sets of output colors represented in an output color space are generated, wherein each set of output colors is generated by transforming the set of input colors using a respective one of a plurality of color processing modules. A new color is iteratively added to the set of input colors and the plurality of sets of output colors is regenerated when each set of output colors does not uniquely identify its corresponding color processing module. Each set of output colors is identified as a color processing module fingerprint when each set of output colors uniquely identifies its corresponding color processing module.

Abstract: A system and method for creating gamma correction data for a hardcopy device includes generating a data pattern, the data pattern including data representing color pixels and monochrome pixels, dithering the color pixels of the data pattern, and error diffusing the monochrome pixels of the data pattern such that the dithered color pixels and the error diffused monochrome pixels are each N-bit values, N being greater than one. A test pattern is generated based on the dithered color pixels and the error diffused monochrome pixels. The test pattern is scanned into scanned image data, and a plurality of color gamma correction curves and a monochromatic gamma correction curve are generated from the scanned image data.

Abstract: Disclosed is a system of image data conversion, capable of setting conversion characteristics with more ease even for data having mixed image attributes, and of reducing the amount of data and the size of memory required. The conversion system includes processing elements in a processor array, each including at least an input data register, character registers, an attribute register, and a global processor, so that a calculator in each of the processing elements operates to select, and store in the character registers, the data set, xi, yi, and ai, corresponding to attribute data stored in the attribute register, to be conversion processed subsequently according to an expression stored in the global processor.

Abstract: Methods and apparatus for internally correcting spherical aberration in a scanning imaging system. An example scanning imaging system includes an objective that converges an optical beam received from an external source through a flat plate onto an object and a component that corrects the optical beam for spherical aberration that is produced by the flat plate. The component includes a plurality of lenses that perform cancellation of the spherical aberration produced by the flat plate. The plurality of lenses acts as an afocal element. In another aspect of the invention, the component transforms the received optical beam into an annulus by partially blocking the optical beam. The component that blocks the optical beam includes a holographic element or a catadioptric element.

Abstract: The display device is able to make an image of a dark scene to become easy to see without increasing a contrast. A composite video signal from an input terminal (1) is supplied to a separating circuit 2, in which it is separated to provide a luminance signal and two color-difference signals. The luminance signal thus separated is supplied to a dynamic gamma circuit (5). In this dynamic gamma circuit (5), its gamma correction curve between an input and an output thereof is changed in response to a control signal from a control circuit (11) in such a manner that an intermediate signal level is increased from approximately a straight line, for example. Then, the luminance signal thus gamma-corrected and two color-difference signals are converted by a converting circuit (6) into three primary color signals, and supplied through respective A/D-converting circuits (7R, 7G, 7B) to a display means (8) such as a plasma display or the like.

Abstract: An image processing apparatus that processes image data and transmits processed image data to an external unit includes a content determination unit that determines content of image processing to be applied to image data for each image data, an image processing unit that applies the image processing of the content determined by the content determination unit to the image data, and a transmission unit that transmits the image data processed by the image processing unit to an external unit.

Abstract: In an image forming circuit, a color image forming apparatus using it, and an image forming method according to this invention, the number of LUTs or RAMs which require different settings for four colors is decreased to two from four in the prior art. By alternately using the two LUTs or RAMs, the capacity, power consumption, and cost can be reduced while required performance such as the processing speed is maintained.

Abstract: A method of mapping an input color gamut of an input device onto an output color gamut of an output device includes establishing a threshold chroma value in the input color gamut. For first input chroma values below the threshold chroma value, each first input chroma value is mapped onto a respective one of a plurality of first output chroma values such that a first linear relationship exists between the first input chroma values and the first output chroma values. Each corresponding first input lightness value is mapped onto a respective one of a plurality of first output lightness values such that a second linear relationship exists between the first input lightness values and the first output lightness values. For second input chroma values above the threshold chroma value, each second input chroma value is mapped onto a respective one of a plurality of second output chroma values such that a first non-linear relationship exists between the second input chroma values and the second output chroma values.

Abstract: A system and method for enhancing digital images containing both text and pictorial content (“mixed document images”) utilizes an estimated illumination surface for a given digital image to correct the undesirable effect of non-uniform illumination. The estimated illumination surface is based on the luminance values of the edge pixels of the given image that are on the dark side of text edges. In an alternative embodiment, the luminance values of the edge pixels that are on the lighter side of the detected text edges are used to generate the estimated illumination surface. The estimated illumination surface is applied to the digital image to compensate for illumination variations in the image due to non-uniform illumination. In addition to non-uniform illumination correction, the system and method enhances the mixed document images by sharpening and/or darkening edges of text contained in the images.

Abstract: An efficient method of computing gamma correction tables of the present invention includes the following steps: determining a gamma correction equation between luminance values produced between two representations; determining at least one polynomial approximation to the gamma correction equation, the at least one polynomial approximation having coefficient values cI; for each coefficient value cI, grouping together all of the coefficient values over a range of &ggr; and then fitting a polynomial equation to each grouping to get a respective coefficient polynomial equation; computing coefficients for a given value of &ggr; using the coefficient polynomial equations; computing gamma conversion transformations using the computed coefficients and a simplified mathematical formula; and storing the computed gamma conversion transformations in a gamma correction table.

Abstract: An image processor includes: a color conversion unit for converting an input signal to color signals of at least four colors; a gamma correction unit for performing gamma correction on the color signals; a binarization unit for binarizing the color signals through comparison with a threshold value; a superimposing unit for superimposing a color signal of at least one color but of the binarized color signals on another color signal to convert the signals to a superimposed color signal; logical operation unit for performing a logical operation previously defined for an image of three or fewer colors on the superimposed color signal; and a separator for separating color signals as an output of the logical operation unit into separated color signals of at least four colors.

Abstract: Rapid development of silver bromoiodide color negative photographic films and formation of high quality negative images suitable for scanning to produce display images of excellent quality is made possible by a novel developer solution composition and method of development. The solution is characterized by containing, in addition to the color developer compound and conventional photographic developer solution components, a water soluble pyrrolidone polymer, a high concentration of sulfite ion and a low concentration, or the absence of, bromide ion. In the novel method the developer composition contacts the exposed film at elevated temperature, e.g., 40 to 66° C., for a short development time, e.g., 20 to 90 seconds. The developed image has image quality suitable for scanning and digital manipulation to produce a digital record for forming a color display image of high quality.

Abstract: A data driver of a display forming an image frame by sequentially scanning horizontal lines. The data driver comprises a shift register receiving image data of three primary colors in serial and outputting them in parallel within each scan duration, a sample and hold register acquiring the image data from the shift register, a gamma multiplexer outputting gamma reference voltages for the three primary colors in a predetermined sequence within each scan duration, three DACs receiving the image data of the three primary colors from the sample and hold register and the gamma reference voltages from the gamma multiplexer, and outputting calibrated image signals of the three primary colors, respectively, and three buffers receiving the calibrated image signals from the three digital-to-analog converters in the sequence of the primary colors.

Abstract: An image reading apparatus is arranged to illuminate a transparent or transmissive original with light fluxes emitted by a plurality of light emission parts which differ in wavelength characteristic from each other, to select by means of a reflection mirror the wavelength characteristics of light fluxes emitted from the light emission parts, and to control each of the light emission parts every time a scanning motion is made by an original-placing board relative to an image pickup part.

Abstract: A method for determining information parameter(s) useful in processing a digital image having color values with an extended color gamut, includes the steps of: adjusting the color values of the extended color gamut digital image to fit within a limited color gamut to form a limited color gamut digital image; determining a residual image representing a difference between the extended color gamut digital image and the limited color gamut digital image; and analyzing the residual image to determine one or more image information parameter(s) related to the information contained in the residual image such parameter(s) being useful in processing the digital image.

Abstract: A method and system for determining a transition model between input pixel samples from which output sample values are calculated based on various relative background and brightness conditions of the input pixel samples. A brightness condition is determined from the input sample values associated with the input pixel samples. A first transition model that preserves a constant luminance is used where the brightness condition is indicative of light isolated pixels and a second transition model that preserves a constant darkness is used where the brightness condition is indicative of dark isolated pixels. The resampling circuit may also use alternative models for other brightness conditions, such as for pixel transitions without any emphasis or alternating pixels. The resampling circuit may also perform modified operations for pixels arranged in a diagonal fashion.

Abstract: An image sensing apparatus comprising an image sensor that senses an image of a subject, a parameter setting unit that sets a parameter used for a predetermined developing processing, and an image processing unit that selects raw data from the image sensing unit or externally supplied raw data, and performs the developing processing for the selected raw data, employing the parameter set by the parameter setting unit.