JP2006352475A - Device, method and program for calculating color gamut contour, and storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain color gamut contours in other color spaces when total amount restriction is provided in a device color space with high precision, at high speed and a low cost in addition to guaranteeing that a device color signal on the color gamut contours comprised of the device color space is unique and to further control precision of the color gamut contours under the total amount restriction. <P>SOLUTION: An upper half contour and a lower half contour are constructed by an upper half contour construction part 11, a lower half contour construction part 12, respectively, by contour points which satisfy a limiting value of the total amount of color materials set by a setting part 3 of the limiting value of the total amount of color materials among contour points on the color gamut contours in the device color space. In addition, a regulation contours used as the limiting value of the total amount of color materials is constructed by a regulation contour construction part 13 and the color gamut contours in the device color space which satisfy the limiting value of the total amount of color materials are calculated by the upper half contour, the lower half contour and the regulation contour. The color gamut contours in an optional color space are calculated by converting the contour points on the color gamut contours into color signals in the optional color space by a color space conversion part 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for calculating a color gamut outline that is a color reproduction range of an output device that performs output using four or more color materials including achromatic colors such as CMYK. More specifically, the present invention relates to a technique for accurately calculating a color gamut outline even when the total amount of color material that can be output by an output device that is a target for calculating the color gamut outline is limited.

  Color output devices such as color laser printers, color inkjet printers, printing presses, CRTs, and liquid crystal displays have device-specific characteristics such as a color gamut that is a reproducible color range. The color gamut of this device is used when the color signal to be output is converted into a color that can be output by the target device. Therefore, in order to realize highly accurate color reproduction according to the purpose, a technique for calculating the color gamut with high accuracy is required.

  As a conventional method for calculating the color gamut, as described in Patent Document 1, for example, white (W), cyan (C), magenta (M), yellow (Y ), Red (R), green (G), blue (B), and black (K), and connecting adjacent vertices to calculate 12 triangles to obtain a color gamut outline. As another method, as described in Patent Document 2, for example, there is a method of creating a color gamut outline by sampling vertices where a plurality of planes perpendicular to the lightness axis intersect the color gamut. These methods have problems such as being unsuitable for the purpose of calculating the color gamut outline with high accuracy and requiring a huge amount of calculation to achieve the purpose. As a method for solving these problems, for example, as in the technique described in Patent Document 3, the object is to reduce the amount of calculation by using a vertex group whose adjacency relation in the device color space is clear. There is a method for calculating a highly accurate color gamut.

  Here, as a matter to be considered when calculating the color gamut of a color output device such as a color laser printer or a color inkjet printer, there is a restriction on the total amount of toner and ink. This is because, in the case of a color laser printer, all color materials cannot be loaded on 100% paper at the same time due to limitations such as output speed, toner characteristics, and fixing device performance. For example, the total amount of toner is up to 300%. There are many cases where restrictions are imposed on Also, in the case of a color ink jet printer, the total amount of ink is usually limited to 200% due to restrictions such as output speed, ink characteristics, and paper water absorption characteristics.

  However, Patent Document 3 does not provide a method for calculating a color gamut in consideration of the limitations on the total amount of toner and ink described above.

  As a technique for solving this problem, there are techniques described in Patent Documents 4 and 5. The technique described in Patent Document 4 is a method of calculating the color gamut of the CMYK output device by searching in consideration of the total amount restriction, and the technique described in Patent Document 5 is a high method in consideration of the total amount restriction. This is a method for calculating the color gamut of a color output device with high accuracy and high speed.

  In particular, Patent Document 5 solves the problem related to the calculation amount and the prediction accuracy in Patent Document 4, and as a feature, the color gamut contour is defined by the contour point group based on the device color signal that is clearly defined in the device color space. At the same time, correction is performed so as to satisfy the total amount restriction for the outline points that do not satisfy the predetermined total amount restriction among the outline points by each device color signal. Through this series of processing, a color gamut outline consisting only of device color signals (corrected outline point group) satisfying the total amount restriction can be constructed, and then the device color signals corresponding to each outline point after correction are device independent such as CIELAB. By converting to a color signal, the color gamut contour can be calculated in the device independent color space.

  As described above, the method described in Patent Document 5 corresponds to an outline point that does not satisfy the total amount restriction with respect to a color gamut outline constituted by outline points based on device color signals formed on the device color space. The device color signal is corrected to a device color signal that satisfies the total amount restriction. Therefore, when a total amount limit of less than 200% is imposed, the result is that the outline point group based on the device color signal of the color gamut outline configured on the device color space is corrected so as to satisfy the total amount limit. In some cases, outline points of different device color signals are corrected to the same device color signal (corrected outline points). For example, when CMYK = (100, 100, 0, 0) and CMYK = (90, 90, 0, 0) exist as two outline points on the color gamut outline configured on the CMYK device color space, If correction is performed under the condition that the total amount limit value is 160%, both of the two outline points are corrected to device color signals (corrected outline points) on the color gamut outline of CMYK = (80, 80, 0, 0). .

  Since Patent Document 5 is a method of calculating the color gamut outline in the device independent color space using the adjacency relationship of the outline points on the color gamut outline in the device color space, as described above, the color gamut outline that should be different from the original color gamut should be used. If multiple contour points that make up a contour become one modified contour point, they cannot be used in the process of using the calculated color gamut contour or the handling of the calculated color gamut contour becomes complicated There is.

  In addition, the accuracy and calculation amount of the color gamut outline calculated in Patent Document 5 are in a trade-off relationship, and the calculation amount increases as the number of divisions for dividing the color gamut outline configured in the device color space into a lattice shape increases. Instead of increasing, the accuracy of the color gamut outline is improved. At this time, if a relatively large total amount limit is imposed, many of the outline points by the device color signal that constitutes the color gamut outline in the device color space are corrected, and the total amount value equal to the total amount limit value is set. The outline point group after the correction by the device color signal is relatively increased. However, in Patent Document 5, since the number of contour points after correction by the device color signal having the total amount value equal to the total amount limit value cannot be controlled independently, calculation according to the required color gamut accuracy is required. There is a problem that a calculation amount exceeding the amount is required.

JP-A-7-203235 Japanese Patent Laid-Open No. 7-30774 JP 2000-101863 A JP 2003-8912 A JP 2005-63093 A

  The present invention has been made in view of the above-described circumstances, and a device on a color gamut outline in which a color gamut outline in another color space when a total amount restriction is provided in the device color space is configured by the device color space. A color gamut outline calculation method that can be obtained with high accuracy, high speed, and low cost while ensuring that the color signal is unique, and that can control the accuracy of the color gamut outline under the total amount limitation, and An object of the present invention is to provide a color gamut outline calculation device. It is another object of the present invention to provide a program for causing a computer to execute the function of the color gamut outline calculation method or the color gamut outline calculation apparatus, and a storage medium storing such a program.

  The present invention relates to a color gamut contour calculation apparatus and a color gamut contour calculation device for calculating a color gamut contour that satisfies a color material total amount limit value in a color output device that outputs a color image according to a device color signal in a device color space of three or more dimensions that does not include black In the outline calculation method, an upper half outline, a lower half outline, and a restriction outline that are outline points on the color gamut outline in the device color space and that are outline points that satisfy the color material total amount limit value are obtained. The upper half outline is composed of outline points that satisfy the color material total amount limit value among outline points that are points on the color gamut outline where one or more color components are 0%. Further, the lower half outline includes outline points that satisfy the color material total amount limit value among outline points that are points on the color gamut outline where one or more color components are 100%. These upper half outline and lower half outline are a part of the outline surface in the device color space, but the points that do not satisfy the color material total amount limit value are excluded, so the upper half outline and the lower half outline are closed spaces. It will not be. For this reason, a regulation outline is obtained which is connected to the total color material amount limit value in the upper half outline and the lower half outline or an outline point in the vicinity thereof and uses a device color signal equal to the total color material quantity limit value as an outline point. Then, the upper half outline, the lower half outline, and the regulation outline are converted into a color space other than the device color space to obtain color gamut outlines in different color spaces.

  The present invention also relates to a color gamut outline calculation device and a color gamut outline calculation apparatus for calculating a color gamut outline that satisfies a color material total amount limit value in a color output device that outputs a color image according to a device color signal in a device color space of four or more dimensions including black. In the contour calculation method, in this case as well, contour points on the color gamut contour in the device color space, which are contour points that satisfy the total color material amount limit value, are obtained, and intermediate contours are obtained. A restriction outline is obtained which is connected to the color material total amount limit value in the outline of the color or the outline points in the vicinity thereof and uses a device color signal equal to the color material total quantity limit value as the outline point. The upper half outline is composed of outline points that satisfy the total color material amount limit value among the outline points that are points on the color gamut outline in which black is 0% and one or more color components other than black are 0%. The intermediate outline satisfies the total color material amount limit value among the outline points that are points on the color gamut outline in which one or more color components other than black are 100% and one or more color components other than black are 0%. It is made up of contour points that have been corrected so as to satisfy the total color material amount limit value. Further, the lower half outline includes outline points that satisfy the total color material amount limit value among the outline points that are points on the color gamut outline in which black is 100% and one or more color components other than black are 100%. Then, by converting the outline points of the upper half outline, the middle outline, the lower half outline, and the regulation outline to a color space other than the device color space, a color gamut outline in a different color space is obtained. is there.

  When obtaining the intermediate outline, the black color can be fixed and subtracted by an equal amount from the remaining color components other than 0% so that it can be corrected to be equal to the total color material amount limit value. At this time, outline points that cannot be corrected so as to satisfy the color material total amount limit value may be deleted.

  In addition, when obtaining the lower half outline and the upper half outline, if the outline point that exceeds the color material total amount limit value and the adjacent outline point is less than the color material total amount limit value, the outline point that exceeds the color material total amount limit value is determined. It may be corrected so as to be equal to the color material total amount limit value.

  According to the present invention, a color gamut outline that satisfies the total color material amount limit value is obtained in the device color space before color conversion, and the color gamut outline in the device color space is converted to another color space. This eliminates the problem that different outline points are converted to the same color gamut outline, which occurs when a color gamut outline satisfying the total color material amount limit value is searched after color conversion as before. Can do. Therefore, it is possible to guarantee that the color signal of the color gamut outline converted into another color space is unique. In addition, it is easy to find color gamut outlines (upper half outline, lower half outline, regulated outline, intermediate outline) that satisfy the total color material amount limit value in the device color space, compared to the case of searching in a conventional manner. Therefore, the color gamut outline can be obtained at a low cost.

  FIG. 1 is a block diagram showing a first embodiment of the present invention. In the figure, 1 is a device outline constructing section, 2 is a color space conversion section, 3 is a color material total amount limit value setting section, 11 is an upper half outline construction section, 12 is a lower half outline construction section, and 13 is a regulation outline construction section. is there. In the first embodiment, the color output device for which the color gamut outline is to be obtained outputs a color image according to a device color signal in a three-dimensional or higher device color space that does not include black, for example, a CMY color space. Indicates the case of a thing.

  The total color material amount limit value setting unit 3 sets a total color material amount limit value that is the maximum value of the total amount of color materials that can be used to form a color image with the target color output device. As a method of setting the total color material amount limit value, for example, the user may specify the total color material amount limit value through the user interface, or a unique color for each type of color output device or for each output mode of the color output device. The total material amount limit value may be determined in advance, and an appropriate color material total amount limit value may be set according to the type of color output device to be used and the output mode. Of course, it can be given in advance as a fixed value.

  The device outline construction unit 1 creates a color gamut outline in the device color space of the target color output device. Here, as described in Patent Document 4 and Patent Document 5, a color gamut outline in which the total amount of color materials in the device color space is not limited can be easily constructed. For example, in a three-dimensional color space such as a CMY color space or an RGB color space, a color gamut outline can be constructed as the surface of a cube or a rectangular parallelepiped.

  However, in the device outline construction unit 1 according to the present invention, the color gamut outline of the color output device that does not include black is an outline based on the device color signal that does not exceed the color material total amount limit value set by the color material total amount limit value setting unit 3. Must be constructed to consist of only points. More specifically, color output that does not include the black ink described above is deleted by removing the outline points that exceed the color material total amount limit value from the outline points that constitute the color gamut outline under conditions where the total amount of color material is not limited. The color gamut outline of the device is configured only from outline points based on device color signals that do not exceed the total color material amount limit value set by the total color material amount limit value setting unit 3.

  Of the outline points that make up the color gamut outline under conditions where the total amount of color material is not limited, the total color material amount of the outline point adjacent to the outline point to be deleted because the total color material amount limit value has been exceeded is the color material. If it is less than the total color material amount limit value set by the total amount limit value setting unit 3, the device color signal of the outline point is set to be equal to the total color material amount limit value without deleting the outline point to be deleted. Correct it. Accordingly, an outline point equal to the total color material amount limit value can be provided, and the color gamut outline can be obtained more accurately.

  In this example, the device outline constructing unit 1 includes an upper half outline constructing part 11, a lower half outline constructing part 12, and a regulation outline constructing part 13. Hereinafter, the upper half outline construction part 11, the lower half outline construction part 12, and the regulation outline construction part 13 will be described in detail.

  The upper half outline construction unit 11 constructs an upper half outline among the color gamut outlines of the target color output device. The upper half outline represents the total color material amount limit value set by the total color material amount limit value setting unit 3 among the outline points that are points on the color gamut outline in which one or more color components in the device color space are 0%. Consists only of outline points by the device color signal to be satisfied. For example, if the device color space is a CMY color space, the color material total amount limit value setting unit 3 among the regularly arranged outline points where any element of C, M, and Y is 0% is set. The upper half outline can be constructed with outline points that do not exceed the total color material amount limit value. Here, the regularly arranged outline points mean that adjacent outline points can be easily specified, and the interval between adjacent outline points may be irregular. Here, in order to simplify the description, the upper half outline is constituted by outline points arranged at equal intervals. The same applies to the lower half outline and the regulation outline described below, and the intervals may be irregular. However, for convenience of explanation, the outlines are constituted by outline points arranged at equal intervals.

  The construction of the upper half outline is obtained by deleting the outline points that exceed the color material total amount limit value from the outline points that are points on the color gamut outline where one or more color components in the device color space are 0%. be able to. At this time, when the total color material amount of the outline point adjacent to the outline point to be deleted is less than the total color material amount limit value set by the color material total amount limit value setting unit 3, the outline point to be deleted is deleted. The device color signal of the outline point to be deleted is corrected so as to be equal to the total color material amount limit value, and the corrected outline point is included in the upper half outline.

  The lower half outline constructing unit 12 constructs a lower half outline among the color gamut outlines of the target color output device. The lower half outline represents the total color material amount limit value set by the total color material amount limit value setting unit 3 among the outline points that are points on the color gamut outline where one or more color components in the device color space are 100%. Consists only of outline points by the device color signal to be satisfied. For example, if the device color space is the CMY color space, the color material total amount limit value setting unit 3 among the regularly arranged outline points in which any element of C, M, and Y is 100% is set. A lower half outline can be constructed with outline points that do not exceed the total color material limit.

  The construction of the lower half outline is obtained by deleting the outline points that exceed the color material total amount limit value from the outline points that are points on the color gamut outline where one or more color components in the device color space are 100%. be able to. At this time, when the total color material amount of the outline point adjacent to the outline point to be deleted because the total color material amount limit value is exceeded is less than the total color material amount limit value set by the color material total amount limit value setting unit 3 The device color signal of the outline point to be deleted is corrected so as to be equal to the total color material amount limit value without deleting the outline point to be deleted, and the corrected outline point is included in the lower half outline.

  Depending on the total color material amount limit value set by the total color material amount limit value setting unit 3, the lower half outline may not exist. For example, when the device color space is the CMY color space and the color material total amount limit value of the color output device is 90%, all of the outline points of the lower half outline, which is 100% even for one color, all have the color material total amount limit value. Since it does not satisfy, the lower half outline does not exist.

  The regulation outline construction unit 13 constructs a regulation outline composed only of outline points regularly arranged equal to the color material total quantity limit value set by the color material total quantity limit value setting unit 3. The restriction outline is connected to the color material total amount limit value or the outline point in the vicinity thereof in the lower half outline and the upper half outline, and constitutes the color gamut outline of the color output device together with the lower half outline and the upper half outline. Become.

  Note that there may be no restriction outline due to the total color material amount limit value set by the total color material amount limit value setting unit 3. For example, when the device color space is the CMY color space and the color material total amount limit value of the color output device is 300%, that is, when the total color material amount is substantially equal to no limit, the total color material amount limit Since the contour points equal to the value are only CMY = (100%, 100%, 100%) and the contour cannot be formed, there is no restriction contour.

  As described above, the device outline construction unit 1 includes the upper half outline construction part 11, the lower half outline construction part 12, and the regulation outline construction part 13, and constructs an upper half outline, a lower half outline, and a regulation outline, respectively. By connecting these outlines with the same outline points in the outline, the color gamut outline of the color output device not including the target black can be constructed in the device color space.

  In addition, when connecting the upper half outline, the lower half outline, and the regulation outline, each outline is constructed by the color material total amount limit value, the upper half outline construction section 11, the lower half outline construction section 12, and the regulation outline construction section 13. Depending on the number of outline points used (distance between outline points), there may be cases where outline points that do not match are generated. In this case, the outline points may be added or modified so that all the outline points coincide at the connected portion.

  In the device outline construction unit 1, the order of the construction of the upper half outline by the upper half outline construction part 11, the construction of the lower half outline by the lower half outline construction part 12, and the construction of the regulation outline by the regulation outline construction part 13 are arbitrary. Yes, you can do it in parallel.

  The color space conversion unit 2 wants to construct a color gamut using device color signals corresponding to the outline points constituting the color gamut outline in the device color space of the color output device that does not include the target black constructed by the device outline construction unit 1. Conversion to a color signal in a desired color space. In the present invention, the color space conversion of the conversion destination is not limited. Therefore, any method may be used as long as it can be converted into a color signal in a desired color space. For example, a color conversion definition formula may be used, a physical model such as Neugebauer may be used, or a regression formula or a model based on a neural network may be used.

  For example, the device color space constructed by the device outline constructing unit 1 is calculated by calculating the color gamut in the CIELAB color space, which is a device-independent color space, and using the method described in JP-A-10-262157. The device color signal corresponding to the outline points constituting the color gamut outline in FIG. 4 can be converted into the CIELAB color signal.

  Hereinafter, the operation of each unit will be further described using specific examples. In the following description, the color gamut of a CMY printer that forms a color image using C, M, and Y color materials as a color output device is calculated. Further, both cases will be described assuming that the total color material amount limit value setting unit 3 sets 250% or 150% as the total color material amount limit value.

  The upper half outline constructing section 11 of the device outline constructing section 1 constructs an upper half outline in the CMY color space which is a device color space. FIG. 2 is an explanatory diagram of an example of the upper half outline when the total color material amount limit value is 250% in the first embodiment of the present invention, and FIG. 3 is an example of the upper half outline when the color material total amount limit value is 150%. It is explanatory drawing of. 2A and 3A are development views of the upper half outline, and FIGS. 2B and 3B are overhead views of the upper half outline. Further, black circles in the figure are outline points constituting the upper half outline. A polygon group representing the upper half outline can be created by connecting the regularly arranged outline points to adjacent outline points to form a triangle (solid line in FIGS. 2 and 3). In the developed views shown in FIGS. 2 (A) and 3 (A), the outline points aligned horizontally have the same total color material amount. This relationship is the same in other developed views in this specification.

  In the CMY printer, each color component C, M, Y can take a value of 0 to 100%. Therefore, the color gamut outline that does not consider the total color material amount limit value in the CMY color space that is the device color space is a cube. It becomes the surface of. Among them, the upper half outline is composed of three surfaces that are in contact with the origin and each axis. As in the example shown in FIG. 2, when the total color material amount limit value is 250%, all of the outline points on these surfaces satisfy the total color material amount limit value, and thus are the outline points for constructing the upper half outline. .

  When the total color material amount limit value is 150%, the total color material amount limit value is not satisfied at some of the outline points for each of the three surfaces that are in contact with the origin and each axis. For example, the outline point of M = 0% and C = Y = 100% is C + M + Y = 200%, which exceeds the color material total amount limit value of 150%. Therefore, as shown in FIG. 3, an upper half outline lacking a part of each surface is obtained. For example, the outline point of M = 0% and C = Y = 100% is C + M + Y = 200%, which exceeds the color material total amount limit value of 150%. If M = 0%, the in-plane outline points satisfying C + Y ≦ 150% constitute the upper half outline. From another point of view, the shape is cut at 45 degrees along a straight line of C + Y = 150% (FIG. 3B). In FIG. 3A, a part of the upper half outline is constructed by the upper outline points including the horizontal line connecting the outline points G1 and G2 with C + Y = 150%. The same applies to the case of C = 0% and Y = 0%.

  The lower half outline constructing unit 12 constructs a lower half outline in the CMY color space which is a device color space. FIG. 4 is an explanatory diagram of an example of the lower half outline when the total color material amount limit value is 250% in the first embodiment of the present invention, and FIG. 5 is an example of the lower half outline when the total color material amount limit value is 150%. It is explanatory drawing of. 4A and 5A are development views of the lower half outline, and FIGS. 4B and 5B are overhead views of the lower half outline. Further, black circles in the figure are outline points constituting the lower half outline. A polygon group representing the lower half outline can be created by connecting the regularly arranged outline points to adjacent outline points to form a triangle (solid line in FIGS. 4 and 5).

  As described above, the color gamut outline that does not consider the total color material amount limit value in the CMY color space in the CMY printer is the surface of a cube. Of these, the one or more color components are 100% on the remaining three surfaces of the six surfaces of the cube, excluding the three surfaces shown in FIG. When the total color material amount limit value is 250%, as shown in FIG. 4, a part of these faces lacking is the lower half outline.

  When the total color material amount limit value is 150%, most of the three surfaces do not satisfy the total color material amount limit value, and only the triangular portion becomes the lower half outline as shown in FIG. In FIG. 5B, a color gamut outline that does not consider the color material total amount limit value is indicated by a dotted line.

  The restriction outline construction unit 13 constructs a restriction outline in the CMY color space that is a device color space. FIG. 6 is an explanatory diagram of an example of a regulation outline when the total color material amount limit value is 250% in the first embodiment of the present invention, and FIG. 7 is an explanation of an example of a regulation outline when the total color material amount limit value is 150%. FIG. 6 (A) and 7 (A) are development views of the restriction outline, and FIGS. 6 (B) and 7 (B) are overhead views of the restriction outline. Moreover, the black circles in the figure are outline points that constitute the restriction outline. By connecting the regularly arranged outline points to the adjacent outline points to form a triangle (solid line in FIGS. 6 and 7), a polygon group representing the restriction outline can be created.

  The restriction outline is a surface equal to the total color material amount limit value set by the total color material amount limit value setting unit 3, and in the CMY color space, a surface having an inclination of −45 degrees with respect to each axis (C + M + Y = Part of the color material total amount limit value). The portion surrounded by the intersection line between this surface and the surface of the cube, which is the color gamut contour that does not consider the color material total amount limit value, is the regulation contour. Specifically, when the total color material amount limit value is 250%, it becomes as shown in FIG. 6, for example, the regulation outline shown in FIG. 6B lacks the lower half outline shown in FIG. 4B. The outer surface closes the part. Similarly, when the total color material amount limit value is 150%, the result is as shown in FIG. 7. For example, the restriction outline shown in FIG. 7B is a portion lacking the lower half outline shown in FIG. The outline surface closes the lacked portion of the upper half outline shown in FIG.

  FIG. 8 shows the color gamut outline in an example of the color gamut outline obtained by collecting the upper half outline, the lower half outline, and the regulation outline obtained when the total color material amount limit value is 250% in the first embodiment of the present invention. FIG. 9 is an overhead view of FIG. FIG. 10 is a developed view of the color gamut outline in an example of the color gamut outline when the total color material amount limit value is 150% in the first embodiment of the present invention, and FIG. 11 is an overhead view of the same. The black circles in the figure are outline points that make up the color gamut outline, and by creating a triangle (solid line in FIGS. 8 to 11) by connecting adjacent outline points, a polygon group representing the color gamut outline is created. can do.

  For the upper half outline, the lower half outline, and the regulation outline constructed as described above, by connecting these outlines at the same outline point existing at the edge portion, the color that satisfies the total color material amount limit value of the CMY printer The area outline can be constructed in the device color space. Contour points that do not match may be dealt with by adding contour points or modifying the contour points.

  The color gamut outline constructed when the total color material amount limit value is 250% is shown in FIGS. 8 and 9, and the color gamut outline constructed when the color material total amount limit value is 150% is shown in FIGS. , Respectively. For example, the color gamut outline shown in FIGS. 8 and 9 is obtained by connecting the upper half outline shown in FIG. 2, the lower half outline shown in FIG. 4, and the regulation outline shown in FIG. Similarly, the color gamut outlines shown in FIGS. 10 and 11 are obtained by connecting the upper half outline shown in FIG. 3, the lower half outline shown in FIG. 5, and the regulation outline shown in FIG.

  The outline points constituting the color gamut outline thus obtained are converted into color signals in an arbitrary color space in the color space conversion section 2. For example, it can be converted into a CIELAB color space, which is a device-independent color space.

  In general, the color gamut outline of the CMY printer in the CIELAB color space has a complicated shape, and obtaining a color gamut outline that satisfies the total color material amount limit value after performing color conversion first requires a large amount of processing, and is time consuming. This was a treatment. However, in the present invention, color conversion is performed after obtaining a color gamut outline that satisfies the total color material amount limit value in the device color space before color conversion. As can be seen with reference to FIGS. 9 and 11, the color gamut outline that satisfies the color material total amount limit value has a relatively simple shape in the device color space. Therefore, the process for obtaining the color gamut outline in the device color space is easy, and can be obtained at a very high speed as compared to the conventional case where it is obtained in an exploratory manner.

  Further, as described in Patent Document 5, the outline points exceeding the color material total amount limit value are not corrected. In the present invention, the upper half outline, the lower half outline, and the regulation are set so as to satisfy the color material total amount limit value. Construct an outline and a color gamut outline. Accordingly, it is possible to eliminate the inconvenience such as duplication of the corrected outline points that occurred in Patent Document 5, and to determine the number of outline points constituting the color gamut outline according to the accuracy of the target color gamut outline. It is possible to reduce a useless calculation amount and accurately obtain a color gamut outline in an arbitrary color space.

  FIG. 12 is a block diagram showing a second embodiment of the present invention. In the figure, the same parts as those in FIG. 4 is a device outline construction section, 21 is an upper half outline construction section, 22 is a lower half outline construction section, 23 is an intermediate outline construction section, and 24 is a regulation outline construction section. In the second embodiment, the color output device for which the color gamut outline is to be obtained outputs a color image in accordance with a device color signal in a four or more-dimensional device color space including black, for example, a CMYK color space. Show the case.

  The total color material amount limit value setting unit 3 is the same as that in the first embodiment described above, and the total color material amount limit that is the maximum value of the total amount of color material used by the target color output device to form a color image. Set the value. The setting method is arbitrary.

  The device outline constructing unit 4 creates a color gamut outline in the device color space of the target color output device. Here, as described in Patent Document 5, a color gamut outline in which the total amount of color materials in the device color space is not limited can be easily constructed. FIG. 13 is an explanatory diagram of an example of a color gamut outline in the CMYK color space. For example, the color gamut outline in the CMYK color space which is a four-dimensional color space including black (K) is a 12-sided polyhedron as shown in FIG. For convenience of illustration, FIG. 13 shows three surfaces in which at least one of CMYK is 0% in FIG. 13A, and the other nine surfaces are shown in FIG. 13B.

  However, in the device outline construction unit 1 according to the present invention, the color gamut outline of the color output device including black is an outline point based on the device color signal that does not exceed the color material total amount limit value set by the color material total amount limit value setting unit 3 Must be constructed to consist only of. More specifically, among the color gamut outlines under the condition that the total amount of the color material is not limited, the upper half outline (three faces shown in FIG. 13A) and the lower half outline (FIG. 13B) are hatched. For the three surfaces that are not present, the outline points that exceed the color material total amount limit value are deleted from the outline points constituting these outlines. As for the outer outline (six sides hatched in FIG. 13B), the outline of the outline constituting the intermediate outline that exceeds the color material total quantity limit value is the color material total quantity limit value. Modify to be equal. Furthermore, a regulation outline consisting only of outline points equal to the color material total amount limit value is constructed. As a result, the color gamut outline of the color output device including black can be configured only from outline points based on device color signals that do not exceed the total color material amount limit value set by the total color material amount limit value setting unit 3.

  Of the outline points that make up the color gamut outline under conditions where the total amount of color material is not limited, the total color material amount of the outline point adjacent to the outline point to be deleted because the total color material amount limit value has been exceeded is the color material. If it is less than the total color material amount limit value set by the total amount limit value setting unit 3, the device color signal of the outline point is set to be equal to the total color material amount limit value without deleting the outline point to be deleted. Correct it. Accordingly, an outline point equal to the total color material amount limit value can be provided, and the color gamut outline can be obtained more accurately.

  In the second embodiment, the device outline construction unit 4 includes an upper half outline construction part 21, a lower half outline construction part 22, an intermediate outline construction part 23, and a regulation outline construction part 24. Hereinafter, the upper half outline construction part 21, the lower half outline construction part 22, the intermediate outline construction part 23, and the regulation outline construction part 24 will be described in detail.

  The upper half outline construction unit 21 constructs an upper half outline among the color gamut outlines of the target color output device. The upper half outline is the color among the outline points that are points on the color gamut outline where K = 0% in the device color space of the fourth or higher order including black and one or more other color components are 0%. It is composed only of outline points based on device color signals that satisfy the total color material amount limit value set by the total material amount limit value setting unit 3. For example, if the device color space is the CMYK color space, the total color material amount limit value setting unit among the regularly arranged contour points where K = 0% and any element of C, M, Y is 0% The upper half outline can be constructed with outline points that do not exceed the color material total amount limit value set in 3. Here, the regularly arranged outline points mean that adjacent outline points can be easily specified, and the interval between adjacent outline points may be irregular. Here, in order to simplify the description, the upper half outline is constituted by outline points arranged at equal intervals. The same applies to the lower half outline, the intermediate outline, and the regulation outline described below, and the intervals may be irregular. However, for the convenience of explanation, the outlines are configured by outline points arranged at equal intervals.

  The construction of the upper half outline exceeded the color material total amount limit value among the outline points that are points on the color gamut outline where K = 0% and one or more other color components become 0% in the device color space. The outline points can be obtained by deleting them. At this time, when the total color material amount of the outline point adjacent to the outline point to be deleted is less than the total color material amount limit value set by the color material total amount limit value setting unit 3, the outline point to be deleted is deleted. The device color signal of the outline point to be deleted is corrected so as to be equal to the total color material amount limit value, and the corrected outline point is included in the upper half outline.

  The lower half outline constructing unit 22 constructs a lower half outline among the color gamut outlines of the target color output device. The lower half outline is a color among the outline points which are points on the color gamut outline where K = 100% and one or more other color components are 100% in a device color space of four or more dimensions including black. It is composed only of outline points based on device color signals that satisfy the total color material amount limit value set by the total material amount limit value setting unit 3. For example, if the device color space is the CMYK color space, the color material total amount limit value setting unit among the regularly arranged contour points where K = 100% and any element of C, M, and Y is 100% The lower half outline can be constructed by the outline points that do not exceed the color material total amount limit value set in 3.

  The construction of the lower half outline exceeded the color material total amount limit value among the outline points that are points on the color gamut outline where K = 100% and one or more other color components are 100% in the device color space. The outline points can be obtained by deleting them. At this time, when the total color material amount of the outline point adjacent to the outline point to be deleted because the total color material amount limit value is exceeded is less than the total color material amount limit value set by the color material total amount limit value setting unit 3 The device color signal of the outline point to be deleted is corrected so as to be equal to the total color material amount limit value without deleting the outline point to be deleted, and the corrected outline point is included in the lower half outline.

  Depending on the total color material amount limit value set by the total color material amount limit value setting unit 3, the lower half outline may not exist. For example, when the device color space is the CMYK color space and the total color material amount limit value of the color output device is 190%, any of C, M, and Y can be 100% and K = 100%. Therefore, all the outline points of the lower half outline do not satisfy the color material total amount limit value, and the lower half outline does not exist.

  The intermediate outline constructing unit 23 constructs an intermediate outline among the color gamut outlines of the target color output device. The intermediate outline is hatched at an outline point (FIG. 13B) that is a point on the color gamut outline in which one or more color components excluding black are 100% and one or more color components excluding black are 0%. The total color material amount for the outline points that satisfy the color material total amount limit value set by the color material total amount limit value setting unit 3 and the outline points that do not satisfy the color material total amount limit value in the device color signal on the applied surface) It can be constructed with contour points modified to be equal to the limit value. For example, if the device color space is a CMYK color space, the C, M, and Y elements are regularly arranged with 100% and any other C, M, and Y elements at 0%. By modifying the outline points that exceed the total color material amount limit value set by the total color material amount limit value setting unit 3 so as to be equal to the total color material amount limit value, the intermediate outline can be constructed. Note that this intermediate outline may not exist depending on the total color material amount limit value set by the color material total amount limit value setting unit 3.

  The restriction outline construction unit 24 constructs a restriction outline composed only of outline points regularly arranged equal to the color material total quantity limit value set by the color material total quantity limit value setting unit 3. This restricted outline is connected to the color material total amount limit value in the lower half outline, the middle outline, and the upper half outline or the outline points in the vicinity thereof, and together with the lower half outline, the middle outline, and the upper half outline, together with the outside of the color output device color It will constitute Guo.

  Note that there may be no restriction outline due to the total color material amount limit value set by the total color material amount limit value setting unit 3. For example, when the device color space is the CMYK color space and the color material total amount limit value of the color output device is 400%, that is, when the total color material amount is substantially unlimited, the total color material amount limit Since the contour points equal to the value are only CMYK = (100%, 100%, 100%, 100%) and the contour cannot be constructed, there is no restriction contour.

  As described above, the device outline construction unit 4 includes the upper half outline construction part 21, the lower half outline construction part 22, the intermediate outline construction part 23, and the regulation outline construction part 24, and the upper half outline, the lower half outline, and the intermediate outline, respectively. By constructing the regulation outline and connecting these outlines at the same outline points in these outlines, the color gamut outline of the color output device including the target black can be constructed in the device color space.

  When connecting the upper half outline, the lower half outline, the intermediate outline, and the restriction outline, the total color material amount limit value, the upper half outline construction part 21, the lower half outline construction part 22, the intermediate outline construction part 23, the regulation Depending on the number of outline points used when the outline construction unit 24 constructs each outline (interval between the outline points), there may be an outline point that does not match. In this case, the outline points may be added or modified so that all the outline points coincide at the connected portion.

  In the device outline construction unit 1, the order of the construction of the upper half outline by the upper half outline construction part 11, the construction of the lower half outline by the lower half outline construction part 12, and the construction of the regulation outline by the regulation outline construction part 13 are arbitrary. Yes, you can do it in parallel.

  The color space conversion unit 2 converts the device color signal corresponding to the outline points constituting the color gamut outline in the device color space of the color output device including the target black constructed by the device outline construction unit 4 as described above into the color The color is converted into a color signal in a desired color space for which a region is to be constructed. In the present invention, the color space conversion of the conversion destination is not limited. Therefore, any method may be used as long as it can be converted into a color signal in a desired color space. For example, a color conversion definition formula may be used, a physical model such as Neugebauer may be used, or a regression formula or a model based on a neural network may be used.

  For example, a device color space constructed by the device outline constructing unit 4 using a method described in Japanese Patent Laid-Open No. 10-262157, which calculates a color gamut in the CIELAB color space, which is a device-independent color space. The device color signal corresponding to the outline points constituting the color gamut outline in FIG. 4 can be converted into the CIELAB color signal.

  Hereinafter, the operation of each unit will be further described using specific examples. In the following description, it is assumed that the color gamut of a CMYK printer that forms a color image using C, M, Y, and K color materials is calculated as a color output device. Further, both cases will be described assuming that the total color material amount limit value setting unit 3 sets 250% or 150% as the total color material amount limit value.

  The upper half outline constructing section 21 of the device outline constructing section 4 constructs the upper half outline in the CMYK color space which is a device color space including black. FIG. 14 is an explanatory diagram of an example of the upper half outline when the total color material amount limit value is 250% in the second embodiment of the present invention, and FIG. 15 is an example of the upper half outline when the color material total amount limit value is 150%. It is explanatory drawing of. 14A and 15A are developed views of the upper half outline, and FIGS. 14B and 15B are correspondence tables of the respective vertexes and device color signals shown in the developed views. Further, black circles in the figure are outline points constituting the upper half outline. A polygon group representing the upper half outline can be created by connecting the regularly arranged outline points to adjacent outline points to form a triangle (solid line in FIGS. 14 and 15).

  In the CMYK printer, the upper half outline that does not consider the color material total amount limit value in the CMYK color space, which is the device color space, is composed of three surfaces shown in FIG. When the total color material amount limit value is 250%, all of the outline points on these surfaces satisfy the total color material amount limit value, and thus are the outline points for constructing the upper half outline (FIG. 14).

  When the total color material amount limit value is 150%, the total color material amount limit value is not satisfied at some of the outline points for each of the three surfaces that are in contact with the origin and each axis. For example, the outline point of M = K = 0% and C = Y = 100% is C + M + Y + K = 200%, which exceeds the color material total amount limit value of 150%. If M = K = 0%, the in-plane outline points satisfying C + Y ≦ 150% constitute the upper half outline. In the development shown in FIG. 15A, a part of the upper half outline is constructed by the upper outline points including the horizontal line connecting the outline points G1 and G2 with C + Y = 150%. The same applies to the case of C = K = 0% and Y = K = 0%.

  The lower half outline construction unit 22 constructs a lower half outline in the CMYK color space, which is a device color space including black. FIG. 16 is an explanatory diagram of an example of the lower half outline when the total color material amount limit value is 250% in the second embodiment of the present invention. FIG. 16A is a developed view of the lower half outline, and FIG. 16B is a correspondence table of each vertex and device color signal shown in the developed view. Further, black circles in the figure are outline points constituting the lower half outline. By connecting the regularly arranged outline points to the adjacent outline points to form a triangle (solid line in FIG. 16), a polygon group representing the lower half outline can be created.

  In the CMYK printer, the lower half outline that does not consider the total color material amount limit value in the CMYK color space, which is the device color space, is composed of three surfaces that are not hatched in FIG. When the total color material amount limit value is 250%, as shown in FIG. 16, a part of these faces lacking is the lower half outline. For example, if C = K = 100%, the outline points in the plane satisfying Y + M ≦ 50% (= 250−200) constitute the lower half outline. In the development shown in FIG. 16A, a part of the lower half outline is constructed by the upper outline points including the horizontal line connecting the outline points GK2 and BK1 with Y + M = 50%. The same applies to the case where M = K = 100% and Y = K = 100%.

  When the total color material amount limit value is 150%, all the outline points constituting the lower half outline are deleted, so there is no lower half outline. That is, since the lower half outline is composed of outline points where K and the other one color are 100%, the total color material amount is 200% or more. Therefore, when the total color material amount limit value is 150%, all the outline points constituting the lower half outline do not satisfy the total color material amount limit value, and therefore the lower half outline does not exist.

  The intermediate outline constructing unit 23 constructs an intermediate outline in the CMYK color space, which is a device color space including black. FIG. 17 is an explanatory diagram of an example of an intermediate outline when the total color material amount limit value is 250% in the second embodiment of the present invention. FIG. 17A is a developed view of the intermediate outline, and FIG. 17B is a correspondence table between each vertex and the device color signal shown in the developed view. Also, the black circles in the figure are the outline points that constitute the intermediate outline as they are, and the black squares are outline points that are corrected to become the intermediate outline. A polygon group representing an intermediate outline can be created by connecting the regularly arranged outline points to adjacent outline points to form a triangle (solid line in FIG. 17).

  Here, since the outline points indicated by the black squares directly exceed the color material total amount limit value 250%, the CMYK device color signals corresponding to these outline points are made equal to the color material total amount limit value 250%. Must be corrected. As this correction method, the color material amount of black (K) is fixed and the other color materials are reduced by equal amounts, so that the device color signal equal to the total color material amount limit value can be corrected.

For example, the fixed color material amount is K, the color gamut contour point of the device color space is (C, M, 0, K), and the color gamut contour point of the device to which the total color material amount limit value L is imposed is (C ′ , M ′, Y ′, K), C ′, M ′, Y ′ is C ′ = C− (C + M + Y + KL) / 2.
M ′ = M− (C + M + Y + KL) / 2
Y '= 0
Is obtained. Here, C ≠ 0 and M ≠ 0.

Further, the fixed color material amount is K, the device color gamut outline point is (C, 0, 0, K), and the color gamut outline point of the device color space to which the color material total amount limit value L is imposed is (C ′, M ′, Y ′, K), C ′, M ′, Y ′ are C ′ = LK
M '= 0
Y '= 0
Is obtained. Here, C ≠ 0.

  As an example of this calculation, the device color signal BK100 = (100%, 100%, 0%, 100) which is one of the outline points shown in FIG. 17 that exceeds the set total color material amount limit value. %) Is corrected, BK100 ′ = (75%, 75%, 0%, 100%).

  Further, as described in Patent Document 5, it is also possible to fix the color material amount of one color and match the color material total amount limit value set with the composition ratio of the other color material amounts being constant. However, it should be noted that in this case, it is not possible to easily determine the outline point corresponding to the joint with the regulation outline.

  FIG. 18 is an explanatory diagram of an example of an intermediate outline before correction when the total color material amount limit value is 150% in the second embodiment of the present invention, and FIG. 19 is an example of an intermediate outline after correction. It is explanatory drawing. FIGS. 18A and 19A are development views of the intermediate outline, and FIGS. 18B and 19B are correspondence tables of the vertexes and device color signals shown in the development views. Further, black circles and black squares in the figure are the same as those in FIG. Also in this case, a polygon group representing the intermediate outline can be created by connecting the outline points regularly arranged to the adjacent outline points to form a triangle (solid line in FIGS. 18 and 19).

  Here, the outline points indicated by the black squares exceed the total color material amount limit value of 150%, and the CMYK device color signals corresponding to these outline points must be corrected to be equal to the total color material amount limit value of 150%. I must. As described above, this correction method can be corrected to the set color material total amount limit value by fixing black (K) and reducing the other color materials by an equal amount. As an example of this calculation, the device color signal BK1 = (100%, 50%, 0%, 100) which is one of the outline points exceeding the set total color material amount limit value among the outline points shown in FIG. %) Is corrected, BK1 ′ = (50%, 0%, 0%, 100%).

  When the set total color material amount limit value is less than 200%, some elements of the device color signal corresponding to the outline points on the intermediate outline may become negative due to correction. In this case, the negative element is changed to 0, and the positive element excluding the fixed K (which should be only one) is corrected so as to be equal to the set total color material amount limit value. You can make corrections. For example, when CMYK = (100%, 20%, 0%, 100%) is calculated according to the above equation under the condition that the color material total amount limit value is 150%, C′M′Y′K = (65%, -15%, 0%, 100%). Since the element M ′ is negative, further correction as described above results in C ″ M ″ Y ″ K = (50%, 0%, 0%, 100%). Since the same device color signal appears at the outline points constituting the intermediate outline after correction, it is necessary to delete overlapping outline points when creating polygons between adjacent outline points.

  In this way, when the set total color material amount value is 150%, the outline points that exceed the total color material amount limit value are corrected, and the outline points that do not constitute an effective polygon are deleted, thereby making it possible to perform FIG. An intermediate outline as shown in Fig. 2 is obtained. Note that the outline points indicated by black squares in FIG. 19 are all outline points that are equal to the total color material amount limit value, even if shown at the top and bottom.

  The restriction outline construction unit 24 constructs a restriction outline in the CMYK color space, which is a device color space including black. FIG. 20 is an explanatory diagram of an example of a regulation outline when the total color material amount limit value is 250% in the second embodiment of the present invention, and FIG. 21 is an explanation of an example of the regulation outline when the total color material amount limit value is 150%. FIG. FIGS. 20A and 21A are development views of the regulation outline, and FIGS. 20B and 21B are correspondence tables of the vertices and device color signals shown in the development views. Moreover, the black circles in the figure are outline points that constitute the restriction outline. By connecting the regularly arranged outline points to the adjacent outline points to form a triangle (solid line in FIGS. 20 and 21), a polygon group representing the restriction outline can be created.

  The restriction outline is a surface that is equal to the total color material amount limit value set by the total color material amount limit value setting unit 3, and in the CMYK color space, K = 100% and C + M + Y = total color material amount limit value−K. . Specifically, when the total color material amount limit value is 250%, the result is as shown in FIG. 20, a part of the outer periphery is connected to the lower part of the lower half outline shown in FIG. The other part becomes an outer surface connected to the intermediate outer case shown in FIG. At this time, in the connection portion of the intermediate outline shown in FIG. 17A with the restriction outline, the outline points exceeding the color material total amount limit value are corrected to be equal to the color material total amount limit value as described above. Yes. Therefore, the number of outline points to be connected increases, and in the regulation outline, the outline points are increased by three on three sides of the hexagon so as to correspond to the outline points of the intermediate outline.

  Similarly, when the total color material amount limit value is 150%, the result is as shown in FIG. 21. For example, the regulation outline shown in FIG. 21 (A) is located below the corrected intermediate outline shown in FIG. 19 (A). Connected.

  The color space conversion unit 2 converts the outline points on the color gamut outline constituted by the upper half outline, the lower half outline, the intermediate outline, and the restriction outline thus obtained into color signals of an arbitrary color space. For example, it can be converted into a CIELAB color space, which is a device-independent color space. As a result, the color gamut outline of the CMYK printer can be obtained in an arbitrary color space.

  As described above, according to the second embodiment, among the outline points constituting the color gamut outline in the color output device having the device color space of four or more dimensions including black, it is set in the intermediate outline. The device color signal of the outline points exceeding the total color material amount limit value is corrected to be equal to the total color material amount limit value, and the outline points exceeding the total color material amount limit value are excluded in the upper half outline and lower half outline. An outline is constructed from only the outline points, a restriction outline equal to the total amount restriction value is constructed, and these are combined to construct a color gamut outline in the device color space. Then, by converting the outline points constituting the color gamut outline in the device color space into color signals in the desired color space, the color gamut outline imposed on the total color material amount limit set in the desired color space is obtained. It can be calculated. Accordingly, an appropriate color gamut outline corresponding to an arbitrary color material total amount limit value larger than 100% can be constructed. Further, since color conversion is performed after the color gamut outline is constructed in the device color space, it is not necessary to search for a color signal satisfying the total color material amount limit value as in the prior art, and processing can be performed at high speed. . In addition, as described in Patent Document 5, the outline points exceeding the color material total amount limit value are not corrected, but the restriction outline is constructed and the color gamut outline is constructed. At the same time, the number of outline points constituting the color gamut outline can be determined in accordance with the accuracy of the target color gamut outline, and a wasteful calculation amount can be reduced.

  In the specific examples in the first and second embodiments described above, the CMY color space color output device and the CMYK color space color output device have been described for the sake of simplicity. Similarly, the present invention can be applied to an output device having 5 dimensions or more including black ink.

  FIG. 22 is an explanatory diagram of an example of a computer program and a storage medium storing the computer program when the function of the color gamut outline calculation device or the color gamut outline calculation method of the present invention is realized by a computer program. In the figure, 31 is a program, 32 is a computer, 41 is a magneto-optical disk, 42 is an optical disk, 43 is a magnetic disk, 44 is a memory, 51 is a magneto-optical disk apparatus, 52 is an optical disk apparatus, and 53 is a magnetic disk apparatus.

  Part or all of the configuration described as the first and second embodiments described above can be realized by a program 31 that can be executed by a computer. When the program 31 is realized as described above, the program 31 and data used by the program can be stored in a computer-readable storage medium. A storage medium is a signal format that causes a state of change in energy such as magnetism, light, electricity, etc. according to the description of a program to a reader provided in hardware resources of a computer. Thus, the description content of the program can be transmitted to the reading device. For example, there are a magneto-optical disk 41, an optical disk 42 (including a CD and a DVD), a magnetic disk 43, a memory 44 (including an IC card and a memory card), and the like. Of course, these storage media are not limited to portable types.

  By storing the program 31 in these storage media and mounting these storage media in, for example, the magneto-optical disk device 51, the optical disk device 52, the magnetic disk device 53, or a memory slot (not shown) of the computer 32, the computer 31 It is possible to read the program 31 and execute the function of the color gamut outline calculation apparatus or the color gamut outline calculation method of the present invention. Alternatively, a storage medium may be mounted or built in the computer 32 in advance, and the program 31 may be transferred to the computer 32 via a network, for example, and the program 31 may be stored in the storage medium and executed. Of course, some functions may be configured by hardware, or all may be configured by hardware.

It is a block diagram which shows the 1st Embodiment of this invention. In 1st Embodiment of this invention, it is explanatory drawing of an example of the upper half outline in case color material total amount restriction | limiting value is 250%. In 1st Embodiment of this invention, it is explanatory drawing of an example of the upper half outline in case color material total amount restriction | limiting value is 150%. In 1st Embodiment of this invention, it is explanatory drawing of an example of the lower half outline in case a color material total amount limit value is 250%. In 1st Embodiment of this invention, it is explanatory drawing of an example of the lower half outline in case color material total amount restriction | limiting value is 150%. In 1st Embodiment of this invention, it is explanatory drawing of an example of the control outline in case a color material total amount restriction | limiting value is 250%. In 1st Embodiment of this invention, it is explanatory drawing of an example of the control outline in case a color material total amount restriction | limiting value is 150%. In the first embodiment of the present invention, in the development of the color gamut outline in an example of the color gamut outline obtained by combining the upper half outline, the lower half outline, and the regulation outline obtained when the total color material amount limit value is 250% is there. In the first embodiment of the present invention, an overhead view of the color gamut outline in an example of the color gamut outline obtained by collecting the upper half outline, the lower half outline, and the regulation outline obtained when the total color material amount limit value is 250%. is there. In the first embodiment of the present invention, in the development of the color gamut outline in an example of the color gamut outline obtained by collecting the upper half outline, the lower half outline, and the regulation outline obtained when the total color material amount limit value is 150% is there. In the first embodiment of the present invention, an overhead view of the color gamut outline in an example of the color gamut outline obtained by collecting the upper half outline, the lower half outline, and the regulation outline obtained when the total color material amount limit value is 150%. is there. It is a block diagram which shows the 2nd Embodiment of this invention. It is explanatory drawing of an example of the color gamut outline in CMYK color space. In the 2nd Embodiment of this invention, it is explanatory drawing of an example of the upper half outline in case a color material total amount limit value is 250%. In the 2nd Embodiment of this invention, it is explanatory drawing of an example of the upper half outline in case color material total amount restriction | limiting value is 150%. In the 2nd Embodiment of this invention, it is explanatory drawing of an example of the lower half outline in case a color material total amount limit value is 250%. In the 2nd Embodiment of this invention, it is explanatory drawing of an example of an intermediate outline in case color material total amount restriction | limiting value is 250%. In the 2nd Embodiment of this invention, it is explanatory drawing of an example of the intermediate outline before correction in case a color material total amount restriction | limiting value is 150%. In the 2nd Embodiment of this invention, it is explanatory drawing of an example of the intermediate | middle outline after correction | amendment when a color material total amount restriction | limiting value is 150%. In the 2nd Embodiment of this invention, it is explanatory drawing of an example of the control outline in case a color material total amount restriction | limiting value is 250%. In the 2nd Embodiment of this invention, it is explanatory drawing of an example of the regulation outline in case a color material total amount restriction | limiting value is 150%. It is explanatory drawing of an example of the storage medium which stored the computer program in the case of implement | achieving the function of the color gamut outline calculation apparatus of this invention, or the color gamut outline calculation method with a computer program.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Device outline construction part, 2 ... Color space conversion part, 3 ... Color material total amount limit value setting part, 4 ... Device outline construction part, 11 ... Upper half outline construction part, 12 ... Lower half outline construction part, 13 ... Restriction Outer shell building unit, 21 ... Upper half shell building unit, 22 ... Lower half shell building unit, 23 ... Middle shell building unit, 24 ... Regulatory shell building unit, 31 ... Program, 32 ... Computer, 41 ... Magneto-optical disk, 42 ... Optical disk, 43 ... magnetic disk, 44 ... memory, 51 ... magneto-optical disk apparatus, 52 ... optical disk apparatus, 53 ... magnetic disk apparatus.

Claims (16)

  A color gamut outline calculation apparatus that calculates a color gamut outline that satisfies a total color material amount limit value in a color output device that outputs a color image in accordance with a device color signal in a device color space of three or more dimensions that does not include black. Upper half outline construction means for obtaining an upper half outline composed of outline points satisfying the total color material amount limit value among the outline points which are points on the color gamut outline where the color component is 0%, and 1 in the device color space Lower half outline construction means for obtaining a lower half outline consisting of outline points that satisfy the color material total amount limit value among outline points that are points on the color gamut outline where the color component is 100%, and the lower half outline and A regulation outline construction means for obtaining a regulation outline having a device color signal that is connected to the color material total amount limit value or a neighboring outline point in the upper half outline or equal to the color material total quantity limit value as an outline point; Color gamut boundary calculator device characterized by serial on half shell and said lower half outline from the outline point of the regulating shell has a color space conversion means for obtaining the color gamut boundary of a color space other than the device color space.   In a color gamut outline calculation device that calculates a color gamut outline that satisfies a total color material amount limit value in a color output device that outputs a color image in accordance with a device color signal in a device color space of four or more dimensions including black, black in the device color space Upper half outline construction means for obtaining an upper half outline consisting of outline points satisfying the total color material amount limit value among outline points that are points on the color gamut outline where 0% and one or more color components other than black are 0% And the total color material amount limit value among the outline points that are points on the color gamut outline in which one or more color components other than black in the device color space are 100% and one or more color components other than black are 0%. An intermediate outline constructing means for obtaining an intermediate outline by correcting an unsatisfied outline point so as to satisfy the total color material amount limit value, and 100% of black in the device color space and 100% of one or more color components other than black. Out of color gamut Lower half outline constructing means for obtaining a lower half outline consisting of outline points satisfying the total color material amount limit value among the outline points that are upper points; the lower half outline, the intermediate outline, and the color of the upper half outline A regulation outline constructing means for obtaining a regulation outline having a device color signal that is connected to the material total quantity limit value or its neighboring outline point and having a device color signal equal to the color material total quantity limit value, the upper half outline, the intermediate outline, and the lower outline A color gamut outline calculation apparatus comprising color space conversion means for obtaining the color gamut outline in a color space other than the device color space from an outline point of a half outline and the regulation outline.   3. The intermediate outline constructing means corrects the ink to be equal to the color material total amount limit value by fixing black and subtracting an equal amount from the remaining color components other than 0%. Color gamut outline calculation device.   The color gamut outline calculation apparatus according to claim 2 or 3, wherein the intermediate outline construction unit deletes outline points that cannot be corrected to satisfy the color material total amount limit value.   The lower half outline constructing means and the upper half outline constructing means, when the outline point adjacent to the outline point exceeding the color material total amount limit value is less than the color material total quantity limit value, the outline point exceeding the color material total quantity limit value 5. The color gamut outline calculation device according to claim 2, wherein the color gamut outline calculation device is modified to be equal to the color material total amount limit value.   The lower half outline constructing means and the upper half outline constructing means, when the outline point adjacent to the outline point exceeding the color material total amount limit value is less than the color material total quantity limit value, the outline point exceeding the color material total quantity limit value The color gamut outline calculation apparatus according to claim 1, wherein the color gamut outline calculation device is modified to be equal to the total color material amount limit value.   In a color gamut outline calculation method for calculating a color gamut outline that satisfies a total color material amount limit value in a color output device that outputs a color image according to a device color signal in a device color space of three or more dimensions that does not include black, 1 in the device color space Of the contour points that are points on the color gamut contour where the color component is 0%, the upper half contour composed of the contour points satisfying the total color material amount limit value is obtained by the upper half contour construction means, and 1 in the device color space is obtained. Of the contour points that are points on the color gamut contour where the color component is 100%, the lower half contour consisting of the contour points satisfying the total color material amount limit value is obtained by the lower half contour construction means, and the lower half contour and Of the upper half outlines, the restriction outline construction means obtains a restriction outline that is connected to the color material total quantity limit value or an outline point in the vicinity thereof and has a device color signal equal to the color material total quantity limit value as the outline point. Color gamut boundary calculation method characterized by determining a color space conversion means the color gamut boundary contour and the lower half shell from outline points of the restriction outline in a color space other than the device color space.   In a color gamut outline calculation method for calculating a color gamut outline that satisfies a total color material amount limit value in a color output device that outputs a color image according to a device color signal in a device color space of four or more dimensions including black, the ink in the device color space The upper half outline comprising the outline points satisfying the total color material amount limit value among the outline points which are points on the color gamut outline where 0% and one or more color components other than black are 0% by the upper half outline construction means And determining the total color material amount limit value among the outline points that are points on the color gamut outline in which at least one color component other than black in the device color space is 100% and at least one color component other than black is 0%. The outline points that are not satisfied are corrected so as to satisfy the color material total amount limit value, and the intermediate outline is obtained by the intermediate outline construction means. The black in the device color space is 100% and one or more color components other than black are 100%. On the color gamut outline The lower half outline comprising the outline points satisfying the total color material amount limit value among the outline points that are points is obtained by the lower half outline construction means, and the total color material amount of the lower half outline, the intermediate outline, and the upper half outline The control outline construction means obtains a control outline that is connected to a limit value or a nearby outline point and has a device color signal equal to the color material total amount limit value as an outline point, and the upper half outline, the intermediate outline, and the lower half outline A color gamut outline calculation method, wherein a color space conversion means obtains the color gamut outline in a color space other than the device color space from outline points of the restriction outline.   9. The method according to claim 8, wherein when obtaining the intermediate outline, correction is made to be equal to the color material total amount limit value by fixing black and subtracting an equal amount from the remaining color components other than 0%. The color gamut outline calculation method described.   The color gamut outline calculation method according to claim 8 or 9, wherein when the intermediate outline is obtained, outline points that cannot be corrected to satisfy the total color material amount limit value are deleted.   When obtaining the lower half outline and the upper half outline, if the outline points adjacent to the color material total amount limit value and the adjacent outline points are less than the color material total amount limit value, the outline points exceeding the color material total amount limit value are determined. The color gamut outline calculation method according to claim 8, wherein the color gamut outline calculation method is modified so as to be equal to the color material total amount limit value.   When determining the lower half outline and the upper half outline, if the outline point adjacent to the color material total amount limit value is less than the color material total amount limit value, the outline point exceeding the color material total amount limit value is determined. The color gamut outline calculation method according to claim 7, wherein correction is performed so as to be equal to the total color material amount limit value.   Color gamut outline calculation program for causing a computer to execute a process for calculating a color gamut outline that satisfies a total color material amount limit value in a color output device that outputs a color image according to a device color signal in a device color space of three or more dimensions not including black A color gamut outline calculation device according to claim 1 or 6, or causing a computer to execute the color gamut outline calculation method according to claim 7 or claim 12. Calculation program.   A color gamut outline calculation program for causing a computer to execute processing for calculating a color gamut outline that satisfies a total color material amount limit value in a color output device that outputs a color image according to a device color signal in a device color space of four or more dimensions including black. The function of the color gamut outline calculation device according to any one of claims 2 to 5 or the color gamut outline calculation method according to any one of claims 8 to 11 is executed on a computer. A color gamut contour calculation program characterized in that   A color gamut outline calculation program for causing a computer to execute a process of calculating a color gamut outline satisfying a total color material amount limit value in a color output device that outputs a color image according to a device color signal in a device color space of three or more dimensions not including black. A stored computer-readable storage medium that causes a computer to execute the function of the color gamut outline calculation device according to claim 1 or claim 6 or the color gamut outline calculation method according to claim 7 or claim 12. A computer-readable storage medium storing an outline calculation program.   Stores a color gamut outline calculation program that causes a computer to execute a process of calculating a color gamut outline that satisfies the total color material amount limit value in a color output device that outputs a color image according to a device color signal in a device color space of four or more dimensions including black. 12. The function of the color gamut outline calculation device according to claim 2, or the color gamut outline according to claim 8, in the computer-readable storage medium. A computer-readable storage medium storing a color gamut outline calculation program for causing a computer to execute a calculation method.

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