Abstract: In image processing, it is possible to suitably reduce density unevenness and graininess according to the ink used in printing. More specifically, when dividing multi-valued data and generating data for 2-pass multi-pass printing, in addition to divided multi-valued data for each of the two passes, divided multi-valued data that is common to the two passes is also generated. Moreover, quantized data of that common multi-valued data is reflected on the quantized data for each of the passes. Furthermore, when generating the quantized data, the division ratios used when generating the common data using the aforementioned multi-valued data division are set according to the colors of ink used in printing. By doing so, it becomes possible to suitably reduce density unevenness and graininess according to the colors used in printing.

Abstract: In image processing it is possible to adequately reduce density unevenness and graininess according to the duty of the image data. More specifically, when dividing multi-valued data and generating 2-pass multi-pass printing data, in addition to the divided multi-valued data for each of the two passes, divided multi-valued data that is common to both of the two passes is also generated. Moreover, the quantized data of that common multi-valued data is reflected on the quantized data of each pass. Furthermore, when generating quantized data, the division ratio when generating common data in the division of multi-valued data is set according to the duty (gradation value) of the multi-valued data. By doing so it becomes possible to adequately reduce the density unevenness and graininess according to the duty of the image data.

Abstract: When dividing multi-valued data and generating data for two-pass multi-pass printing, in addition to divided multi-valued data that are divided for each of the two passes, divided multi-valued data that is common to both of the two passes is generated. Moreover, quantized data of that common multi-valued data is reflected onto the quantized data for each pass. Furthermore, when generating quantized data, division ratios that are used when generating the common data by the multi-valued data division described above are set according to the image characteristics (whether or not the area is flesh color) of the multi-valued data. Thereby, it is possible to perform high-quality printing regardless of the image characteristics by taking a suitable balance between suppressing density unevenness and suppressing graininess.

Abstract: When the number (M) of passes is smaller than a threshold value, a first processing mode is selected. In the first processing mode, multivalued image data is divided into pieces of multivalued data corresponding to passes and a common multivalued data for a plurality of passes, the pieces of multivalued data are individually binarized to generate pieces of binary data corresponding to the passes, and the common multivalued data is binarized to generate common binary data for these passes. On the other hand, when the number (M) of passes is equal to or larger than the threshold value, a second processing mode is selected. In the second processing mode, multivalued image data is binarized and the binary data is divided into pieces of binary data corresponding to passes with a mask.

Abstract: Provided are an image processor and an image processing method that are capable of suppressing both density unevenness due to printing position shifts among a group of dots printed by a plurality of relative movements (or a plurality of printing element groups) and graininess. In order to accomplish this, a dot overlap rate in the printing mode in which the density unevenness stands out is made higher than the dot overlap rate in the printing mode in which other defects stand out more than the density unevenness. By doing so, it is possible to suitably adjust the dot overlap rate according to the image characteristic, and output an image having no density unevenness or graininess.

Abstract: Inputted image data is converted to M number of multi-value data having a lower resolution than the inputted image data, and after quantization processing has been performed for each of the M number of multi-value data, an image is printed by M number of relative movements (M-pass printing) that corresponds to the M number of quantized data. By doing so, when compared with the case in which a resolution reduction process is not performed, it is possible to suppress the number of pixels that become the object of quantization processing, and it becomes possible to output an image with no fluctuation in image density or density unevenness without a decrease in the processing speed.

Abstract: Provided is an image processor and image processing method that are capable of suppressing both density unevenness and graininess that occur due to deviation of the printing position of dots that are printed by a plurality of relative movements (or a plurality of printing element groups). In order to accomplish this, the dot overlap rate of an image characteristic in which density unevenness stands out is made higher than the dot overlap rate of an image characteristic in which other defects stand out more than the density unevenness. By doing so, it is possible to suitably adjust the dot overlap rate according to an image characteristic, and to output an image having no density unevenness or graininess.

Abstract: When multi-pass printing is performed, the dot overlap rate (ratio of the number of dots that overlap and are to be printed in the same pixel area by the plurality of relative movements with respect to the total number of dots to be printed in a pixel area by the plurality of relative movements) in pixel areas having medium-density where density unevenness caused by density fluctuation easily stands out is made higher than the dot overlap rate in pixel areas having low-density and pixel areas having high-density. By doing so density unevenness caused by density fluctuation is suppressed. In addition, the dot overlap rate in pixel areas having low-density and pixel areas having high-density is low, so it is possible to reduce graininess in low-density areas and suppress a decrease in density in high-density areas.

Abstract: In a multi-valued printer that uses discontinuous index patterns, if a tone correction table is generated using sampled density patches, a table which is different from a table to be obtained and has no inflection point is obtained, and the print density characteristics after tone correction suffer discontinuity. To solve this problem, an output gamma table used to output measurement patches is set to linearly correct the printer print characteristics. Patches are output and their densities are measured. A reverse table of a “signal value—density” table is generated, and is smoothed using a recursive curve. The smoothed reverse table is finely adjusted to generate an intermediate output gamma table. The generated table undergoes index component correction, thus generating a tone correction table.

Abstract: Color production with high chroma in a low lightness portion is realized by using an appropriate complementary color ink to a particular color ink reproducing the low lightness portion. More specially the device secondary color G-K is reproduced with ink of the pure color component composed of the color mixture of the particular color G ink and the basic color Y ink to tone the particular color G ink. In addition, as complementary color components, the particular color R ink and K ink are used. Thereby, the reproduction line is substantially linear from the device secondary color G point to the device K point. In color reproduction at the dark portion of the color on the G-K line, sufficient chroma can be obtained.

Abstract: Color production with high chroma in a low lightness portion is realized by using an appropriate complementary color ink to a particular color ink reproducing the low lightness portion. More specially the device secondary color G-K is reproduced with ink of the pure color component composed of the color mixture of the particular color G ink and the basic color Y ink to tone the particular color G ink. In addition, as complementary color components, the particular color R ink and K ink are used. Thereby, the reproduction line is substantially linear from the device secondary color G point to the device K point. In color reproduction at the dark portion of the color on the G-K line, sufficient chroma can be obtained.

Abstract: Color reproducibility is improved by enabling one to control a smoothing condition for each of plural positions on color space. When a color correction table is formed by using smoothing, the smoothing conditions respectively corresponding to the plural positions on the color space are set, and then the smoothing is performed according to the smoothing conditions.

Abstract: The color of magenta using newly developed magenta ink has characteristics L*?41, a*?82, and b*?24, and has differences ?L*?4, ?a*?0, and ?b*?26 from the conventional magenta ink, i.e., the lightness value is low, and the color difference b* assumes a very small value. When the color of red is reproduced using such new magenta ink, its lightness and saturation values are low, and subdued red is reproduced, i.e., a visually favorable color cannot be obtained. Hence, when a color included in a first color gamut is input, and the input color is converted into the color of a second color gamut narrower than the first color gamut, color conversion is made using a three-dimensional lookup table having red defined by L*?45 to 50, a*?67 to 70, and b*?50 to 55.

Abstract: An inkjet recording system including a separation unit configured to obtain separated data which corresponds to each of a plurality of nozzle arrays from input image data, a gradation correction unit configured to perform gradation correction by one-dimensional conversion on the separated data obtained by the separation unit, and a quantization unit configured to quantize the data on which the gradation correction is performed by the gradation correction unit to generate the recording data, wherein the separation unit obtains the separated data so that first separated data and second separated data corresponding to at least a pair of nozzle arrays for adjusting an effect of an air current have a same value, and the gradation correction unit performs different gradation correction on the first separated data and the second separated data which have the same value.

Abstract: Lattice point data of each lattice point on W-C line in a color separation table reproducing primary color C is determined so that C ink monotonically increases from W point to C point. Also, particular color G for toning is used to monotonically increase from the halfway of W point to C point and lattice point data is determined so that the basic color C ink and the particular color G ink are mixed at C point. In a case where the reflection characteristics is made such that the basic color C ink thus produces the coloring closer to a blue color, the particular color G ink having high chroma and many portions overlapped in the zone of the C ink and the green color is used at a high density portion of the device primary color C. This realizes control of the hue shift and the high chroma both.

Abstract: The gray axis is adjusted such that an optimal representation can be achieved for low saturation colors close to the gray axis. A test pattern including a plurality of images, which have different color tones is printed, and a user selects a most desirable image. The gray axis of an image recording system is adjusted depending on which image is selected. Each of the plurality of images of the test pattern is a photographic color image represented mainly by low saturation colors close to achromatic colors along the gray axis. In accordance with the selected image, the gradation adjustment is performed for each ink color of the image recording system thereby adjusting the gray axis and the tone of colors close to the gray axis.

Abstract: For obtaining a color reproduction range of a printer closer to the color reproduction range of the positive film, a mere addition of a specific color recording material in the same manner as the recording materials of other colors is insufficient, and, for a specific color showing a large gap from the color reproduction range of the positive film, an application amount different from that of the recording materials of other colors is required for such specific color, in consideration of color developing property. Therefore, in case of forming an image on a recording medium with recording materials of basic colors of cyan, magenta and yellow and recording materials of specific colors different in hue from such basic colors, a maximum application amount per unit area is made larger in at least a recording material of specific color than the application amount of the recording materials of the basic colors.

Abstract: If the grids of a color conversion table are simply downsampled, the way ink is used (the manner of the changeover in the value of a CMYKlclm signal) differs from that color conversion table before downsampling, there is a shift in the starting point of dark ink at the point of changeover of continuous tone ink, and a decline in image quality ascribable to downsampling of the color conversion table tends to occur. Accordingly, an original LUT is read in, a parameter for selecting a grid to be downsampled is set, a table of evaluation values for selecting a grid to be downsampled is created, a grid capable of being downsampled is selected by referring to the evaluation-value table, and table data that does not contain this grid is copied.

Abstract: A high quality gray scale (monochrome) image in which influences of “recorded color deviation” and “color transition” are suppressed is formed even in the case of a slightly uneven discharge amount. When a gray scale (monochrome) mode is set, in the entire range of a luminance signal, density signals corresponding to achromatic dots and small chromatic dots respectively are generated based on the luminance signal so that the density signal corresponding to the achromatic dots has a greater value than that of the density signal corresponding to the small chromatic dots. Accordingly, even a slight “recorded color deviation” that occurs when the achromatic dots are recorded can be corrected by the small chromatic dots having a hue opposite to the direction of color deviation, and a high quality gray scale image in which influences of “recorded color deviation” and “color transition” are suppressed can be formed.

Abstract: When a color reproduction model of a device is generated, colorimetry of a 9×9×9 grid, for example, is performed utilizing equidistant signal values in the color space of the device. Generally, if the number of grid points is increased, the precision with which the color reproduction model is estimated rises but the time needed for measurement is prolonged because the number of colorimetric measurements is also increased. Accordingly, in a printer system comprising a pre-color-processing table for performing color matching and a post-color-processing table for performing color separation, color patches set non-equidistantly in RGB device color space are printed in accordance with changeover of printer CMYKcm signals in the post-color-processing table and the color reproduction model of the printer is generated using data obtained by measuring the colors of the color patches.