Image forming apparatus that ensures highly accurate color conversion to input image with gradation, and recording medium therefor
地域：
Osaka
摘要
An image forming apparatus includes a table generating unit. The table generating unit, in a Voronoi diagram, obtains empty circles as circles centered at Voronoi seeds of ends of Voronoi sides that intersect with a straight line passing through a largest saturation color and a smallest-saturation and specific-lightness color and passes through generatrices. After the table generating unit sets one of the generatrices shared by the two adjacent empty circles whose radius ratio is outside a specific range as a target point, and causes the radius ratio of the two empty circles to be within the specific range by changing at least one radius of the two empty circles, the table generating unit generates the conversion table that sets a color that corresponds to an intersection point corresponding to the target point among the intersection points of the two empty circles, as the definition colors.
說(shuō)明書(shū)
This application is based upon, and claims the benefit of priority from, corresponding Japanese Patent Application No. 2016-108181 filed in the Japan Patent Office on May 31, 2016, the entire contents of which are incorporated herein by reference.
Unless otherwise indicated herein, the description in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
A typical image forming apparatus such as a multi-function peripheral (MFP) and a copy-only machine includes various kinds of color conversion tables and color-adjustment functions to convert an input image into an output image for printing. However, even for an input image with a gradation in which its tone smoothly changes, converting the input image into an output image by some color tables and color-adjustment functions causes such image forming apparatus to generate an output image where tone jump or tone collapse occurs, namely an output image in which tone does not smoothly change.
權(quán)利要求
What is claimed is:1. An image forming apparatus comprising:a central processing unit (CPU); a storage device that stores an image forming program; and a print device that executes printing on a recording medium; wherein the CPU executes the image forming program to function asa table generating unit that generates a second color conversion table based on a first color conversion table, the first color conversion table defining a correspondence relationship between color values of a colorimetric system of an input image and color values of a colorimetric system of an output image for printing by the print device, with respect to a specific count of colors, and a color conversion unit that converts the input image into the output image using the second color conversion table generated by the table generating unit, wherein the table generating unit, in a Voronoi diagram in a specific hue plane that includes generatrices corresponding to definition colors defined in the first color conversion table, obtains empty circles as circles centered at Voronoi seeds of ends of Voronoi sides that intersect with a straight line passing through a largest saturation color and a smallest-saturation and specific-lightness color and passes through generatrices, the circle being without the generatrix inside the circle, and after the table generating unit, among the obtained empty circles, sets one of the generatrices shared by the two adjacent empty circles whose radius ratio is outside a specific range as a target point, and causes the radius ratio of the two empty circles to be within the specific range by changing at least one radius of the two empty circles while the generatrix other than the target point is fixed, the table generating unit generates the second color conversion table that sets a color that corresponds to an intersection point corresponding to the target point among the intersection points of the two empty circles, as the definition colors. 2. The image forming apparatus according to claim 1 , wherein the CPU executes the image forming program to further function as a range accepting unit that accepts designation of the specific range. 3. A non-transitory computer-readable recording medium storing an image forming program to control an image forming apparatus including a print device that executes printing on a recording medium, the image forming program causing the image forming apparatus to function as:a table generating unit that generates a second color conversion table based on a first color conversion table, the first color conversion table defining a correspondence relationship between color values of a colorimetric system of an input image and color values of a colorimetric system of an output image for printing by the print device, with respect to a specific count of colors; and a color conversion unit that converts the input image into the output image using the second color conversion table generated by the table generating unit; wherein the table generating unit, in a Voronoi diagram in a specific hue plane that includes generatrices corresponding to definition colors defined in the first color conversion table, obtains empty circles as circles centered at Voronoi seeds of ends of Voronoi sides that intersect with a straight line passing through a largest saturation color and a smallest-saturation and specific-lightness color and passes through generatrices, the circle being without the generatrix inside the circle, and after the table generating unit, among the obtained empty circles, sets one of the generatrices shared by the two adjacent empty circles whose radius ratio is outside a specific range as a target point, and causes the radius ratio of the two empty circles to be within the specific range by changing at least one radius of the two empty circles while the generatrix other than the target point is fixed, the table generating unit generates the second color conversion table that sets a color that corresponds to an intersection point corresponding to the target point among the intersection points of the two empty circles, as the definition colors.
意見(jiàn)反饋
使用該功能遇到問(wèn)題
該功能需要專業(yè)版企業(yè)版VIP權(quán)限，您可以：
您也可以聯(lián)系官方QQ: 2157717237 電話: 13264338900