Abstract: An image converting method includes the steps of: converting each pixel of an input image into 2-dimensional conversion chromaticity coordinate values which are obtained by projecting conversion chromaticity coordinate values obtained by converting each of said pixels by using parameters for converting in chromaticity coordinates onto a unit plane, and obtaining parameter values in which a barycenter of a color region including the 2-dimensional conversion chromaticity coordinate values are set to ?; and converting the input image by the obtained parameter values.

Abstract: An image processing apparatus for measuring concentration of concentration patterns by optical sensors and correcting image information on the basis of a correction value obtained on the basis of measured concentration values has: a measured concentration value obtaining unit which measures the concentration in different concentration patterns by the optical sensors and obtains the measured concentration values; an estimation value obtaining unit which estimates original concentration by an independent component analysis on the basis of the obtained measured concentration values and obtains an estimation value; and a correction value obtaining unit which obtains the correction value for allowing the measured concentration value to approach the obtained estimation value. An influence of color noises is reduced, thereby correcting an image.

Abstract: An image converting method includes the steps of: converting each pixel of an input image into 2-dimensional conversion chromaticity coordinate values which are obtained by projecting conversion chromaticity coordinate values obtained by converting each of said pixels by using parameters for converting in chromaticity coordinates onto a unit plane, and obtaining parameter values in which a barycenter of a color region including the 2-dimensional conversion chromaticity coordinate values are set to ?; and converting the input image by the obtained parameter values.

Abstract: A light source presuming apparatus includes: a candidate light source color obtaining unit which obtains candidate light source colors; a guide light source color holding unit which holds guide light source colors for guiding obtainment of parameters of a color adaptation model showing color adaptation of the sight sense from the candidate light source colors to a reference light source color; a guide parameter obtaining unit which obtains such parameters so as to be guided to the guide light source colors; an error converging unit which obtains light source colors, as correction candidate light source colors, having the relation showing the color adaptation of the sight sense with the reference light source color by using the color adaptation model shown by guide parameters, substitutes the correction candidate light source colors for the candidate light source colors, and converges errors included in the candidate light source colors; and a light source color presuming unit which presumes the correction can

Abstract: An image processing apparatus for measuring concentration of concentration patterns by optical sensors and correcting image information on the basis of a correction value obtained on the basis of measured concentration values has: a measured concentration value obtaining unit which measures the concentration in different concentration patterns by the optical sensors and obtains the measured concentration values; an estimation value obtaining unit which estimates original concentration by an independent component analysis on the basis of the obtained measured concentration values and obtains an estimation value; and a correction value obtaining unit which obtains the correction value for allowing the measured concentration value to approach the obtained estimation value. An influence of color noises is reduced, thereby correcting an image.

Abstract: Parameters for mapping colors from an input system to an output system are determined by displaying a set of adjustment colors in the input system and outputting a reference color pattern in the output system. A human operator selects the reference colors most closely matching the adjustment colors. The mapping parameters are determined from the operator's selections, by table look-up or by use of a mathematical formula, for example. Accurate color mapping parameters can be generated in this way without the need for trial and error.

Abstract: A print head comprises a plurality of light emitting devices which are arranged such that the adjacent light emitting devices are stepped from each other in the rotation direction of a photosensitive member, or a plurality of light emitting devices which are disposed linearly such that the light emitting devices emit light at different timings each other by employing a delay mechanism. Consequently, it is possible to provide the output pattern capable of directing the human eyes in two dimensions so as to reduce the visible difference in the image density.

Abstract: A method for obtaining spectral sensitivity characteristics of a color image input device such as a color scanner or a like is provided. The most optimum spectral sensitivity characteristics of the color image input device can be obtained by amending CIE XYZ color matching functions so that X, Y and Z values of two color stimuli perceived to be the same in color by observation under a specific illuminant are made equal and by performing linear transformation on the amended color matching function.

Abstract: A method of image transforming is proposed.

Abstract: A light source presuming apparatus includes: a candidate light source color obtaining unit which obtains candidate light source colors; a guide light source color holding unit which holds guide light source colors for guiding obtainment of parameters of a color adaptation model showing color adaptation of the sight sense from the candidate light source colors to a reference light source color; a guide parameter obtaining unit which obtains such parameters so as to be guided to the guide light source colors; an error converging unit which obtains light source colors, as correction candidate light source colors, having the relation showing the color adaptation of the sight sense with the reference light source color by using the color adaptation model shown by guide parameters, substitutes the correction candidate light source colors for the candidate light source colors, and converges errors included in the candidate light source colors; and a light source color presuming unit which presumes the correction can

Abstract: A print head comprises a plurality of light emitting devices which are arranged such that the adjacent light emitting devices are stepped from each other in the rotation direction of a photosensitive member, or a plurality of light emitting devices which are disposed linearly such that the light emitting devices emit light at different timings each other by employing a delay mechanism. Consequently, it is possible to provide the output pattern capable of directing the human eyes in two dimensions so as to reduce the visible difference in the image density.

Abstract: An image converting apparatus has: a parameter setting unit which sets parameters for converting each pixel of an input image into predetermined chromaticity coordinate values; a chromaticity coordinate converting unit which obtains conversion chromaticity coordinate values obtained by converting each pixel by the set parameters; a color region obtaining unit which obtains a color region including 2-dimensional conversion chromaticity coordinate values obtained by projecting each conversion chromaticity coordinate value onto a unit plane; an area calculation processing unit which calculates an area of the color region obtained every parameter and obtains parameter values at the time of the maximum area value; and an image converting unit which converts the input image by the parameter values. The image data unbalanced in color arrangement of an object is converted into image data obtained under an ideal white light source.

Abstract: Parameters for mapping colors from an input system to an output system are determined by displaying a set of adjustment colors in the input system and outputting a reference color pattern in the output system. A human operator selects the reference colors most closely matching the adjustment colors. The mapping parameters are determined from the operator's selections, by table look-up or by use of a mathematical formula, for example. Accurate color mapping parameters can be generated in this way without the need for trial and error.

Abstract: When image data are processed to generate pseudo-tone patterns, a predetermined threshold is modified according to at least two periodic functions with different spatial periods. The picture elements are compared with the modified threshold, and the comparison results are used to generate an output image. The periodic threshold modifications cause dots to appear preferentially in regular patterns, thereby reducing dot noise, and providing improved control over the overlaying of dot patterns in different color planes in a color image.

Abstract: A method for obtaining spectral sensitivity characteristics of a color image input device such as a color scanner or a like is provided.

Abstract: A color correcting apparatus corrects color data according to second ambient light so that an output device outputting a color based on the color data calibrated in first specified ambient light can output almost the same color in the second light. The apparatus comprises a storing section used to store several main component data each representing a different component of light, which are combined to reproduce the second light, an input section used to input several weighing coefficients to assign weight to each of the several pieces of component data when they are combined and a correcting section used to correct color data based on correction parameters obtained using the several pieces of component data stored in the storing section and using the several weighing coefficients input through the input section.

Abstract: An image is coded by counting runs of non-background picture elements, and counting consecutive scanning lines having only background picture elements. Consecutive scanning lines of this type are coded as a single command and value, giving the number of scanning lines. Consecutive scanning lines having identical numbers of runs of non-background picture elements are coded as another single command and value, giving the run count, followed by run information describing each run. Sparse images, consisting mostly of background area, can be coded efficiently in this way.

Abstract: A color correcting apparatus corrects color data according to second ambient light so that an output device outputting a color based on the color data calibrated in first specified ambient light can output almost the same color in the second light. The apparatus comprises a storing section used to store several main component data each representing a different component of light, which are combined to reproduce the second light, an input section used to input several weighing coefficients to assign weight to each of the several pieces of component data when they are combined and a correcting section used to correct color data based on correction parameters obtained using the several pieces of component data stored in the storing section and using the several weighing coefficients input through the input section.

Abstract: An image is divided into blocks and coded by matching each block with a pattern having either a single region, or two or more regions defined by internal edges. The coded value of the block includes a pattern identifier, and a single pixel value for each region in the matching pattern. The coded image is decoded by constructing blocks divided into regions according to the pattern identifiers, and filling each region with the given single pixel value. The decoded blocks may be the same size as the blocks in the original image, or smaller, in which case the decoded image is reduced, or larger, in which case the decoded image is enlarged.

Abstract: A multi-level input image is divided into blocks, each of which is quantized to a bi-level output block. A single quantization error value is calculated for each block, and distributed over neighboring blocks that have not yet been processed. Blocks containing abrupt changes in image content are preferably converted by comparing each picture element individually with a threshold value. Blocks not containing abrupt changes are preferably quantized by comparing the average value of the block with multiple threshold values to determine a multi-level block output value, from which a predetermined pattern of bi-level picture elements is generated.