Abstract: An image processing apparatus includes a generation unit; wherein a first dither pattern and a second dither pattern have same threshold values that are set for same pixels in a first gradation range, and have different threshold values that are set for same pixels in a second gradation range that exceeds the first gradation range; and the generation unit sets a first threshold value for forming dots of the first dither pattern, and generates a first binary data according to whether or not a threshold value corresponding to a target pixel of the first dither pattern is included in the first threshold value, and sets a second threshold value for forming dots of the second dither pattern, and generates a second binary data according to whether or not a threshold value corresponding to a target pixel of the second dither pattern is included in the second threshold value.

Abstract: An image processing apparatus includes an image data acquisition unit to acquire image data by optically reading a document. A frequency distribution acquisition unit acquires a first frequency distribution of luminances from the image data acquired by the image data acquisition unit. A generation unit generates a second frequency distribution of luminances of a background of the document, by using a maximum frequency of the first frequency distribution as a maximum frequency of the second frequency distribution of luminances of the background of the document. An acquisition unit acquires information indicating a degree of deviation of the second frequency distribution from the first frequency distribution. A correction unit corrects the second frequency distribution based on the information indicating the degree of deviation acquired by the acquisition unit.

Abstract: This invention provides a sample print which allows the user to easily set color adjustment parameters. To this end, upon outputting images which undergo color processing using a plurality of different parameter sets, a sample print mode of parallelly outputting a reference image and images which have different parameter sets of the image processing from the reference image, and are arranged around the reference image, and a sample print mode of parallelly outputting the reference image which is arranged at a corner of an image group including images in a specific hue direction, and images which have different parameter sets of the color processing from the reference image and are arranged between the corner and other corners, are prepared.

Abstract: Provided is an image processing apparatus that can accurately and efficiently reduce color unevenness that occurs in a color image, which is formed by color mixture of a plurality of different types of inks, due to a variation in ejection characteristic among nozzles. The inks are respectively ejected from the nozzle arrays to print patches; regions where color correction for test color images should be performed are specified; a different types of color correction processing for color signals corresponding to the color correction regions are performed to print color correction patches; a color correction patch to be used is selected; on the basis of selected color correction processing, a table parameter corresponding to a nozzle is formed; when the plurality of color correction patches are formed, only correction candidate values having larger color differences than a predetermined threshold value in a uniform color space are generated for color signals.

Abstract: An image processing apparatus includes a unit configured to calculate a plurality of characteristic amounts from an input image, a unit configured to calculate a first multidimensional lookup table based on the characteristic amounts, a unit configured to calculate attribute information of a specific object from the input image, a unit configured to calculate a second multidimensional lookup table based on the attribute information, a unit configured to generate a control parameter from the input image, an interpolation unit configured to apply the first and second multidimensional lookup tables to the input image, and a control unit configured to control interpolation intensity of the second multidimensional lookup table using the control parameter.

Abstract: A gradation-correcting curve to correct a gradation of an input image is generated. Gradation correction based on the gradation-correcting curve is made to a boundary pixel of a color-reproduction space at the same saturation as that of a target lattice point and at a hue of the target lattice point. An equal-saturation line is set by using the boundary pixel of the color-reproduction space after the gradation correction. A saturation-correction amount of the target lattice point is decided based on the gradation-correcting curve and the equal-saturation line.

Abstract: Nozzles in a print head are arrayed in a density of 600 dpi. Moreover, a dither matrix has a size of 16 pixels×16 pixels in 600 dpi. The dither matrix is repeatedly used. In the meantime, each of rectangles represents an HS processing unit. WHS=3 pixels. As a consequence, the relationship of a least common multiple below is established in a nozzle array direction: 3×WD=16×WHS. In this case, the cycle of interference unevenness can be prolonged to the least common multiple between WD and WHS, that is, 48 pixels (3WD). In this manner, the size of the dither matrix is not an integral multiple of the HS processing unit width, so that the cycle of interference unevenness can be prolonged more than the size of the dither matrix. Thus, the interference unevenness can be hardly recognized.

Abstract: An image processing apparatus for generating dot data to form an image by forming dots on a recording medium includes a receiving unit, a first, second, and third generating unit, and a correcting unit. The receiving unit receives first and second image data included in image data. The first generating unit generates, per the first image data, first ink color data representing a multi-valued signal value corresponding to an ink color. The second generating unit generates, per the second image data, second ink color data representing a multi-valued signal value corresponding to an ink color. The correcting unit corrects the signal value represented by the generated first and second ink color data. The third generating unit generates, per the first and second ink color data of which the signal values have been corrected, the dot data representing existence of formation of dots to form an image.

Abstract: One dither mask having a highest spacial frequency is selected from a plurality of dither masks. Next, a granularity is obtained with reference to a table based on the selected dither mask and an ejection amount level per area. Moreover, a difference in granularity between adjacent areas is calculated with respect to all of the areas. A maximum value is obtained out of the obtained differences in granularity, and then, the maximum difference in granularity is compared with a determination threshold. When the maximum difference in granularity is the threshold or greater, it is determined whether or not a dither mask having a spacial frequency lower than that of the selected dither mask is stored in a memory. When there are dither masks having lower spacial frequencies, a dither mask having a spacial frequency lower by one level than that of the selected dither mask is selected.

Abstract: An image processing apparatus includes a generation unit; wherein a first dither pattern and a second dither pattern have same threshold values that are set for same pixels in a first gradation range, and have different threshold values that are set for same pixels in a second gradation range that exceeds the first gradation range; and the generation unit sets a first threshold value for forming dots of the first dither pattern, and generates a first binary data according to whether or not a threshold value corresponding to a target pixel of the first dither pattern is included in the first threshold value, and sets a second threshold value for forming dots of the second dither pattern, and generates a second binary data according to whether or not a threshold value corresponding to a target pixel of the second dither pattern is included in the second threshold value.

Abstract: Provided is a dither pattern generation method so that a dot arrangement having excellent dispersibility can be obtained in low-gradation areas for single colors and for mixed colors. The dither pattern generation method generates dot patterns for low-gradation areas having threshold values 1 to S so that high dispersibility is obtained in a cyan dot pattern and a magenta dot pattern, and so that in a combined dot pattern made by combining these dot patterns there are no overlapping pixels. The dither pattern generation method then sets threshold values for a cyan dither pattern and a magenta dither pattern based on these generated dot patterns.

Abstract: Provided is a quantization processing method using dither patterns that make it possible to obtain a dot array having excellent dispersibility even in the case of a single color or mixed color inks. For this purpose, first and second dither patterns are prepared in order to respectively quantize multivalued data for a first ink to different pieces of binary data, respectively. Also, third and fourth dither patterns are prepared in order to respectively quantize multivalued data for a second ink to different pieces of binary data. Further, on the basis of a combination of the multivalued data on the first ink and the multivalued data on the second ink, a quantization unit for the first ink, and a quantization unit for the second ink are determined.

Abstract: The memory size and processing time for the correction of image data carried out to reduce image deterioration caused by nozzle ejection characteristic variation in an inkjet printing apparatus can be minimized. Print heads are provided with pluralities of chips that have nozzle arrays formed from a plurality of nozzles. Overlap portions and non-overlap portions are formed on each chip. An image processing apparatus sets input image data, corresponding to nozzle regions that are defined in nozzle arrays along the alignment direction of the nozzles of the print head and that are composed of a plurality of nozzles, as processing blocks. The input image data is processed according to parameters defined for each of those processing blocks. The boundaries of the nozzle regions corresponding to the input image data of the processing blocks are established according to the boundaries of the overlap portions and the non-overlap portions.

Abstract: An image processing apparatus is provided that is capable of very accurately and efficiently reducing uneven color caused by variation in ejection characteristics among nozzles that eject ink and that occurs in a color image that is formed by mixing a plurality of different kinds of ink. A patch is printed by ejected ink from a plurality of nozzles, a region is specified so as to perform color correction in a test color image that is printed on a printing medium, a plurality of different color correction processing is performed on color signals that correspond to a color correction region, a plurality of color correction patches are printed, a color correction patch to be used is selected from among the plurality of different color correction patches and table parameters that correspond to the nozzles are created based on the selected color correction processing.

Abstract: Because the ejection state of a printing element in a printing apparatus may vary at all times, an inspection item for inspecting a printed image may be set in consideration of the ejection state of the printing element. An inspection item for inspecting a printed image may be set based on information including a temperature characteristic of a printing head and a state of ink such as an elapsed time from the last ejection. This allows image inspection that matches with variations in the ejection state of the printing element.

Abstract: In the present invention, a first calculation unit calculates, based on image data obtained by reading with a reading unit a plurality of patches formed on a printing medium by a plurality of nozzle regions constituting nozzle array of a printing head, respective color specification values of a plurality of correction regions corresponding to a plurality of nozzle regions constituting the nozzle array. Then, a target value setting unit sets, based on the calculated color specification values of the plurality of correction regions, a target color specification value of the patch. Further, a second calculation unit calculates a difference between each of the color specification values of the plurality of correction regions and the target color specification value as a correction amount. After that, based on the correction amount calculated, image data corresponding to an image printed by each of the plurality of nozzle regions are corrected.

Abstract: In an image processing apparatus for carrying out a plurality of correction processes on an input image, a multi-dimensional histogram of the input image is calculated, and a feature amount of the input image for which a specific correction process has been carried out is analyzed based on the multi-dimensional histogram. Then, based on the result of the analysis, correction parameters to be used for another correction process are calculated.

Abstract: Image ink data is generated which represents the absence of ejection of ink corresponding to pixels for which text ink data represents the ejection of ink.

Abstract: When printing an image using a plurality of inks, color unevenness caused by variations in ejection characteristics among nozzles is corrected at suitable timings in accordance with change in the color unevenness over time, and favorable image output without noticeably color unevenness is maintained. For this purpose, parameters are prepared, for colors formed by combinations of at least two colors of ink, the parameters being determined so as to reduce differences in coloration on a print medium caused by individual variations in the ejection characteristics of a plurality of nozzles. When printing, a first color signal included in individual pixels is corrected for a second color signal by using the parameters. Information regarding the ejection volume characteristics of a plurality of nozzles is acquired as appropriate, and by estimating changes in coloration from this information, suitable timings for overwriting such parameters are determined.

Abstract: Provided are an image processing apparatus and an image processing method capable of reducing color unevenness due to variations in ejection characteristics among a plurality of nozzles when printing an image using a plurality of inks. To that end, a first image which is made up a color with noticeable color unevenness and similar colors is printed onto a print medium. The user then specifies a color and a nozzle position where color unevenness has occurred. On the basis of these results, parameters are set for a correction table referenced by an MCS processor. In so doing, it becomes possible to address the factor causing the color unevenness, and mitigate the effects of color unevenness in a focused way without incurring increases in processor load, memory requirements, or processing time as compared to the case of calibrating all lattice points.