JP2009171164A - Color profile creating device, method, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color profile creating device, capable of appropriately reproducing the gradation characteristics of input gamut data, through approximation by the output gamut. <P>SOLUTION: This illustrate color profile creation device has a gamut specification means for specifying an input gamut and an output gamut from among a plurality of gamuts, and a gamut compression means for performing gamut compression from the specified input gamut to the output gamut. Data regarding a plurality of kinds of gamuts which can be specified as the input gamut and the output gamut are stored in a gamut data DB 100. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a color profile creation apparatus, method, and recording medium generated by various gamut compressions such as converting an arbitrary color image signal into a color of a color image output apparatus with limited gamut.

  In a multimedia system centering on a host computer, development of a color matching system (CMS) that performs color matching processing of image data between an input device and an output device is active. Apple's ColorSync (trademark), a representative CMS framework, converts an image signal in a device-dependent color space (Device Dependent Color Space) into a device-independent color space (Device Independent Color Space). Furthermore, a common CMS is realized on the system by converting an image signal in a color space independent of the device into a color space dependent on the output device. Data representing the conversion characteristics for this conversion process is called a profile and is prepared in the host computer for each device, and the color space of the image signal according to the conversion characteristics of the profile automatically or manually selected at the time of conversion. Is converted.

  In the color matching system, color conversion that matches colorimetrically can be performed because the input signal is color-converted to the output signal via a color space that does not depend on the apparatus. However, since the gamut for electrophotography and inkjet printers is generally narrower than that for televisions, CRT displays, etc., the color appearance has been improved even when the gamut of the input color image is different from the gamut of the output device. There has been proposed a color correction method related to gamut compression that matches the two as much as possible. For example, Patent Document 1 discloses a technique in which color saturation with high saturation is reduced.

  However, there is room for improvement in terms of color continuity of input data, that is, gradation. Many proposals have been made to improve this problem. For example, Patent Document 2 discloses a method of smoothing a 3D-LUT parameter in a profile in order to realize a desired color reproduction and reduce gradation skip. Japanese Patent Application Laid-Open No. 2004-228561 discloses a method of expressing a color change locus in an input color reproduction range using a curve and performing mapping conversion based on the correspondence relationship of the curve. Further, Patent Document 4 discloses a method of performing gradation matching between input / output devices.

By the way, in the gamut compression technique described above, since the electrophotographic gamut is extremely narrower than the gamut of the display, there is a problem that even if the setting conditions of the gamut compression method are slightly different, the reproduced color is greatly different. Furthermore, the gamut of the output device itself is also different, so even if the same gamut compression method is applied, the color will be different, and when multiple printers are connected to the network and multiple printers perform distributed printing processing, There was a problem that colors between printers did not match. Patent Document 5 proposes to improve this. In Patent Document 5, representative color data that has been gamut-compressed in advance is placed in a virtual gamut at least for each color system and image forming method of input color data, and gamut compression is performed while referring to the gamut of an arbitrary color output device. Means for performing are disclosed. Since a representative color for input data is determined, an arbitrary color output device attempts to unify the colors by reproducing the representative color as faithfully as possible.
JP 2000-022978 A JP 2002-077659 A JP 2002-033929 A JP 2003-018405 A JP 2002-252785 A

  However, Patent Document 1 is a method of controlling the angle of gamut compression by the brightness position of the highest saturation point of the input / output gamut. However, it is necessary to set the gamut compression direction for each hue, and between input and output. There is a problem that gradation is not preserved. In Patent Document 2, since the 3D-LUT lattice point parameters are directly smoothed, the data can be smoothed, but the target color may not be reproduced. Japanese Patent Application Laid-Open No. 2003-228561 has a method of having a color change locus as a curve, and may not be traced accurately depending on the gamut shape of the apparatus. Japanese Patent Application Laid-Open No. H10-228707 discloses brightness γ conversion between print output image data for each input image, and performs color matching after γ conversion. The target color may not be obtained by this two-stage process. In Patent Document 5, as in Patent Document 1, it is difficult to adjust the angle of the gamut compression destination.

  Further, the mechanism for unifying the colors of Patent Document 5 is not described in Patent Document 1 to Patent Document 4. However, the above-described conventional techniques including Patent Document 5 cannot sufficiently solve the problem of reproducing the gradation characteristics of the input gamut data by appropriately approximating them with the output gamut.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a color profile creation device that can appropriately approximate and reproduce the gradation characteristics of input gamut data with an output gamut.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a gamut designation means for designating an input gamut and an output gamut from a plurality of gamuts, and a gamut for gamut compression from the designated input gamut to the output gamut. And a compression means.

  According to a second aspect of the present invention, in the color profile creation apparatus according to the first aspect, the plurality of gamuts include a first gamut represented by an arbitrary color system, a second gamut of a virtual device, and a color. And a third gamut of the image output device.

  According to a third aspect of the present invention, in the color profile creation device according to the first or second aspect, a point cloud designating unit for designating a point cloud from the input gamut and a point cloud designated for the output gamut. An internal / external determination unit that performs internal / external determination; and a feature amount calculation unit that calculates a feature amount from a point group determined externally as a result of the internal / external determination, and the gamut compression unit uses the calculated feature amount It is characterized by using gamut compression.

  According to a fourth aspect of the present invention, in the color profile creation device according to the third aspect, the point group designating unit designates a point group having a substantially matching hue.

  According to a fifth aspect of the present invention, in the color profile creation device according to the third or fourth aspect, the point group designating unit designates a point group including a white point and a black point of the input gamut. And

  According to a sixth aspect of the present invention, in the color profile creation device according to any one of the third to fifth aspects, the output gamut is determined for at least one point group designated by the point group designation unit. Coordinate designation means for designating coordinates, and feature quantity calculation range dividing means for dividing the feature quantity calculation range of the designated point group using the designated coordinates, wherein the feature quantity calculation means The feature amount is calculated using the feature amount calculation range divided by the feature amount calculation range dividing means.

  The invention described in claim 7 includes a gamut designation step for designating an input gamut and an output gamut from a plurality of gamuts, and a gamut compression step for gamut compression from the designated input gamut to the output gamut. It is characterized by including.

  According to an eighth aspect of the present invention, the color profile creation apparatus performs gamut designation processing for designating an input gamut and an output gamut from a plurality of gamuts, and gamut compression from the designated input gamut to the output gamut. A program for executing gamut compression processing is recorded.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the color profile creation apparatus which can approximate and reproduce the gradation characteristic of input gamut data appropriately with an output gamut.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
[Embodiment 1]
Before describing the apparatus block diagram of the first embodiment, first, an outline of gamut compression according to the present embodiment will be described. Since gamut compression is largely related to high-quality color reproduction of a color image output device, the sRGB data displayed on the color image display device is converted into perceptual space data such as CIELAB and CIECAM02 formulated based on human perception, Processing is performed. Since conversion to these perceptual space data is defined, conversion from sRGB to CIELAB through tristimulus values XYZ or in the reverse direction is possible. A similar conversion is defined in CIECAM02.

  Note that “sRGB” in this specification refers to an international standard for color space established in 1998 by the International Electrotechnical Commission (IEC). “CIELAB” refers to an international standard for uniform color space defined by the International Lighting Association (CIE) and JIS. “CIECAM02” is an abbreviation of “Color Appearance Model 2002” and, like CIELAB, refers to a color appearance model issued by CIE in 2004.

When data is converted to CIELAB, lightness L * and color components a * and b * are obtained. From a * and b *, saturation C and hue H can be calculated by the following equations.
C = √ (a * × a * + b * × b *) Formula (1)
H = atan2 (a *, b *) × 180 / π Formula (2)
However, when a * = b * = 0, H = 0
When H <0, H = 360 + H

  From FIG. 1, the process of pasting the point s on the gamut of the color image display device to the point t on the gamut that can be reproduced by the color image output device by a method such as minimum color difference is called gamut compression. The color reproduction quality of the color image output device is determined depending on where the point s corresponds to the color image output device. However, as shown in FIG. 1, the gamuts of the two machines are greatly different in lightness, saturation, and the like, and therefore, the degree of freedom in placing the point t corresponding to the point s is very large. Even if it is a color image output device, the color material is toner or ink, the number of colors is three colors, four colors or more, and other differences in image forming methods such as electrophotography and ink jet, and the same Even in electrophotography, gamut has various shapes and sizes due to the difference in maximum density. In other words, even if a color profile that simply uses the gamut of the color image output apparatus is created, color reproduction varies depending on the model regardless of the same manufacturer. In addition, since there are too many degrees of freedom in color design, color reproduction varies greatly depending on the skill of the person who creates the color profile.

  As a method of solving this, as shown in FIG. 2, a virtual gamut (= second gamut) is provided between the gamut of the color image display device (= first gamut) and the gamut of the color image output device (= third gamut). There is a method of color conversion by providing a. The degree of freedom in converting from the first gamut to the third gamut (corresponding to the point s to the point t) is limited by placing it at the point v once, so that differences in models and variations in color profile creators are suppressed. It becomes possible to match the taste.

  At the same time, there are three different types of first, second, and third gamuts, so there are six combinations of gamut compression. Therefore, there has been no apparatus or method that can flexibly handle these combinations, satisfy the colors, and satisfy all the items of good gradation reproducibility.

A supplementary description of the first, second, and third gamut will be given with reference to FIG.
In FIG. 3, the left side of the first gamut is the sRGB space (the figure shows an example of each color having 8 bits). In the figure, each axis is equally divided into eight, and there are 9 × 9 × 9 lattice points (8 divisions are an example and are not particularly limited). Black K (0, 0, 0) (= Bp) is at the origin of the sRGB space, and white W (255, 255, 255) (= Wp) is at the farthest place. In addition, a cube composed of eight vertices of WRGBCMYK such as R (255, 0, 0), G (0, 255, 0) is the sRGB color space. sRGB is converted into tristimulus values XYZ by γ conversion or 3 × 3 matrix calculation of equation (3).
X = α00 × R + α01 × G + α02 × B
Y = α10 × R + α11 × G + α12 × B Formula (3)
Z = α20 × R + α21 × G + α22 × B

Furthermore, it is converted into the CIELAB uniform color space by the equation (4).
L * = 116 × (Y / Y0) ^ (1/3) −16
(However, Y / Y0> 0.008856)
a * = 500 × [(X / X0) ^ (1/3) − (Y / Y0) ^ (1/3)]
b * = 200 × [(Y / Y0) ^ (1/3) − (Z / Z0) ^ (1/3)]
(X0, Y0, Z0 are values of the reference reflecting surface) Formula (4)

  Each coefficient α in Expression (3) varies depending on the light source (D50, D65, F11, etc.), but is a coefficient determined for the light source.

  By the way, the hue H can be obtained from the equation (2) using a * and b *. However, it is difficult to grasp the hue from arbitrary RGB data itself in the sRGB space. Therefore, Windows (registered trademark), which is an OS of Microsoft, employs an HLS color space as a Windows Color System. H represents hue, S represents saturation, L represents lightness, sRGB to HLS, and its inverse conversion are also defined by mathematical expressions, and one-to-one conversion is possible. Formulas are omitted. There are other color spaces such as HSV of Apple, but the basic concept is the same, and sRGB is converted into perceptual hue, saturation, and brightness, and color designation from the application is supported. The first gamut in FIG. 3 is an example in which the sRGB color space is equally divided into eight on each axis, but it may be converted directly into the HLS color space and further converted into CIELAB, or separately from the sRGB color space, the HLS color. Each axis may be divided on the space, and the lattice points may be converted into the CIELAB color space. Since the lattice points generated by dividing in the HLS color space can be converted into the sRGB color space, it is possible to easily correspond to the sRGB color space.

  The first gamut in FIG. 3 is a plot of 9 points obtained by dividing R into 8 from Wp in the sRGB color space into L *, a *, and b *. Although it is originally three-dimensional, it is plotted in two dimensions on the L * vs. a * b * plane for easy understanding. Wp corresponds to Wp1, Bp corresponds to Bp1, and R corresponds to R1, and the line formed by Wp1, R1, and Bp1 is a part of the outermost outline of the gamut. This L * a * b * value is mapped to the second gamut, which is a virtual gamut. The second gamut is smaller than the first gamut, and Wp1 of the first gamut is compressed to Wp2, Bp1 to Bp2, and R1 to R2. There are a wide variety of gamut compression methods, but perceptual mapping in which the brightness of the first gamut is relatively mapped to the second gamut is the mainstream for reproducing pictures and the like neatly. Details are omitted.

The data gamut-compressed to the virtual second gamut is further gamut-compressed to the third gamut of the color image output device, indicating that Wp2 has been gamut-compressed to Wp3, Bp2 has been converted to Bp3, and R2 has been gamut-compressed to R3. .
Hereinafter, the gamut compression will be described as being performed in the CIELAB color space, but is not limited thereto.

  FIG. 4 is a block diagram of the apparatus according to the first embodiment, and FIG. 5 shows the processing flow. The gamut data DB 100 stores a lot of data related to the first gamut represented by an arbitrary color system, the second gamut of the virtual device, and the third gamut of the color image output apparatus. For example, the first gamut data is data obtained by dividing each axis of the RGB space and the HLS space by α, β, and γ, data obtained by L * a * b * conversion of the data (FIG. 6A), and the like. The second gamut data is L * a * b * data (FIG. 6B), polygon data representing the shape of the second gamut (FIG. 6C), or the like. Similarly to the second gamut data, the third gamut data is L * a * b * data (FIG. 6D), polygon data representing the shape of the third gamut (FIG. 6C), and the like. There are six combinations of input / output gamuts as shown in FIG.

  Here, each combination example will be described below. When gamut compression is expressed as input gamut → output gamut, number 1 is AdobeRGB → sRGB, number 2 is sRGB → virtual gamut, number 3 is sRGB → color image output device which is conventional gamut compression, and number 4 is virtual gamut → virtual. Gamut, number 5 is virtual gamut → color image output device, number 6 is color image output device → color image output device, and the like.

  There are a plurality of these gamut data. For example, the second gamut may have these modes for photographs, graphics, characters, and each paper type. The third gamut data is stored for each color image output device from the difference in image forming methods such as electrophotography and inkjet, the number of colors of the color material, etc. When setting data in the input / output gamut, It is necessary to specify whether the data is targeted. One example is the use of m data of the symbol [m, n] in FIG. n is a serial number of the number of data. Furthermore, in order to make it easy to set various gamut data as input / output gamuts, a directory structure is provided in the gamut data DB 100 and stored.

  The gamut data DB 100 is accessed with the input / output gamut designation data indicating which of the first to third gamuts is set in the input / output gamut, and the input / output gamut data is specified (S100). The specified input gamut data is stored in the input gamut data storage unit 101 (S101), and the specified output gamut data is stored in the output gamut data storage unit 102 (S102). Here, in the present embodiment, it is assumed that one of the second gamut data is specified as the input gamut data and one of the gamut data of the color image forming apparatus is specified as the output gamut data.

  The point group specifying data is input to the point group specifying unit 103, and the point group is extracted from the input gamut data storage unit 101 (S103). This point group selection will be supplementarily described. Before that, the process until the L * a * b * value of the second gamut is derived will be described. The L * a * b * values of the second gamut are based on the HLS color space shown in FIG. This HLS color space is composed of three dimensions of lightness L on the vertical axis, saturation S on the horizontal axis, and hue H around the vertical axis, and can be represented by a solid of eight vertices of white W, black K, CYM, and RGB. . FIG. 7B shows the lightness L of the HLS color space divided into eight, the saturation S divided into two, the hue H divided into N, and only the R hue cut out into a two-dimensional plane. In the hue R, 23 dots are formed by dividing the lightness L and the saturation S. For each p, the color to be reproduced in the second gamut is set as an L * a * b * value (FIG. 6A). Nine data of p (p0 to p8 in the example) in this R hue is the point group selection data.

  FIG. 8 shows the second gamut data (L * a * b * values) of the selected nine points from p0 to p8 plotted in the CIELAB color space. White W and black K in the HLS color space correspond to the white point (hereinafter referred to as Wp) and black point (hereinafter referred to as Bp) in the CIELAB color space, and correspond to the hue R in the HLS color space in the CIELAB color space. Data is represented by H (R). P0 to p8 in FIG. 8 are on hues that substantially match or match H (R).

  Whether the nine points in FIG. 8 are inside or outside the output gamut data in FIG. 6C is determined by the output gamut inside / outside determination means 104 (S104). The inside / outside determination algorithm is not particularly limited. After the inside / outside determination, point-to-point data is calculated by the point-to-point calculation means 105 as the feature amount of the point group (S105). It supplements about point data. The distance (= color difference) between the nine adjacent points shown in FIG. 8 is calculated. FIG. 9A shows the distance between points D01 to D78 on the straight line from Wp2 to Bp2 for easy understanding. Here, a case where all of p0 to p8 are determined to be outside the third gamut data will be described, and a determination example including the inside will be described later.

  Next, a polyline is generated from the point cloud data and the output gamut data stored in the output gamut data storage means 102 by the polyline generation means 106 (S106). The polyline generating means 106 will be supplementarily described. Since the output gamut data is composed of the polygon data shown in FIG. 6 (c), the solid is cut by a plane perpendicular to the a * b * plane and the hue H (R) angle and the lightness L axis. FIG. 10 shows only the R side. A cross section obtained by cutting a solid composed of polygons by such a plane, that is, an aggregate of fan-shaped lines connecting Wp3 to Bp3 which is the outermost contour is called a polyline. The output gamut data corresponding to the input gamut data Wp2 and Bp2 are Wp3 and Bp3. This polyline is generated by the polyline generating means 106.

  A polyline is reconstructed from the point calculation means 105 and the polyline generation means 106. This reconstruction is performed by the polyline forming means 107 (S107). The detailed description of the polyline forming means 107 will be described later together with gamut inside / outside determination. If all the selected point groups are determined to be outside the output gamut data, the polyline is not reconstructed. The polyline of the output gamut data in FIG. 10 is a straight line of Wp3 and Bp3 as in FIG. 9A, and the point-to-point data D value is mapped to the line segment. The ratio of each D value, which is point-to-point data from Wp2 to Bp2, is stored and converted to a line segment of Wp3 and Bp3. After the conversion, there are nine points p0 'to p8' in FIG. 9B. Nine points and line segments allocated with this D value are mapped to the polyline in FIG. As a result, FIG. 9C is obtained. When FIG. 8 and FIG. 9C are overlapped, FIG. 11 is obtained. The broken line is a diagram after mapping to the polyline in FIG. As a result, the point groups p0 to p8 are gamut-compressed into p0 'to p8'.

  This gamut compression is repeated for all input gamut data. In addition, Wp2, Wp3, Bp2, and Bp3 may not exist on the lightness axis L *, but various methods and algorithms for matching Wp2 to Wp3 and Bp2 to Bp3 are not particularly limited.

  After the processing is completed, it is known how all the points in the input gamut data are gamut-compressed into the output gamut. Using all the data pairs, the color profile generation means 108 in the subsequent stage generates a color profile (S108). The method and algorithm for the color profile generation unit 108 are not particularly limited.

Hereinafter, the processing when the result of the inside / outside determination includes the internal determination will be described.
The point group specifying means 103 selects p0, p9 to p15, and p8 in FIG. 7B, and the output gamut inside / outside determination means 104 determines inside / outside. In FIG. 12A, the nine points and the polyline of the output gamut are indicated by bold lines, the points for external determination are plotted with ●, and the points for internal determination are plotted with ○.

  The point-to-point calculation means 105 calculates distances D0-9, D9-10,..., D14-15, D15-8 between Wp2 and Bp2 shown in FIG. The D value and the inside / outside determination result are input to the polyline forming unit 107. The internally determined p11, p12, and p13 are not subject to gamut compression processing, and the point data for the internal determination is the output gamut data itself. Further, intersection points q10-11 and q13-14 between the polyline of the output gamut and the straight line formed by nine points are obtained, and d10-11 is calculated from the distance between p10 and q10-11. Similarly, q13-14 and p14 determine d13-14. This intersection calculation and the recalculation of the D value and d value for the intersection are executed, and the points obtained by storing and mapping the D value and d value from Wp3 to Bp3 are p9 ', p10', p14 ', and p15'. External determination points are mapped to polylines, and as a result, gamut compression is performed on points p0 ', p9', p10 ', p11, p12, p13, p14', p15 ', and p8' shown in FIG.

  According to the present embodiment described above, when performing various combinations of gamut compression, an appropriate input / output gamut can be designated and gamut compression can be performed, and the gradation characteristics of input gamut data can be expressed as output gamut. Can be approximated and reproduced.

  In addition, according to the present embodiment, the accuracy of matching colors is improved by performing internal / external determination on the output gamut, and without performing gamut compression on internal colors, and faithfully reproducing the input gamut data as it is. Can be made.

  In addition, according to the present embodiment, the feature quantity between points based on the white point and the black point can be approximated by the output gamut, and the approximation accuracy of gradation is improved in addition to the color tone. be able to.

[Embodiment 2]
Next, a second embodiment (Embodiment 2) for carrying out the present invention will be described. First, the problem of this embodiment will be described. As one factor that affects the quality of the color profile for graphics, there is a problem in which color the highest saturation of each color of RGBCMY in the sRGB color space is reproduced by the color image output apparatus. From FIG. 2 showing the state of gamut compression, there is the highest saturation point s of the first gamut. This point is assumed to be R (R, G, B) = (255, 0, 0) in the sRGB color space. For graphics, the point s is made to correspond to the point v as the representative color of the second gamut. It is necessary to determine the point t with the point v as a color to be reproduced by the color image output apparatus. In the first embodiment, the point t of the output gamut is calculated by storing the ratio of the distance (D value) between the point groups selected from the input gamut data. However, referring to FIG. 9C, in some regions surrounded by the polyline, the saturation may be slightly increased compared to p4 ′. On the other hand, there are cases where p4 ′ is too dark. That is, there is a desire to preserve the hue of p4 but change the shade of p4 ′. Therefore, it is necessary to specify the hue and make the maximum saturation point correspond to the desired point.

FIG. 14 shows a device block of this embodiment, and FIG. 15 shows a processing flow diagram thereof. Here, only the parts different from the processing flow diagram of FIG.
Since the hue to be processed is known at the time of inputting the point group selection data, the processing is performed with a desired hue. The point-to-point calculation means 105 inputs desired coordinates as coordinate designation data while referring to the polyline (not shown but displayed on an image display device, for example), and based on this data, the point-to-point calculation means 105 The point-to-point data is calculated (S200). The display method on the color image display device is not particularly limited.

  This point-to-point calculation will be supplemented below. As in the first embodiment, FIG. 7B is used for the point cloud data. The hue is also H (R). A polyline of the output gamut is displayed, and desired coordinates are designated inside the polyline (☆ in FIG. 16). The point cloud data is shown in FIG. The polyline is linearized, and the mapping result including the coordinate designation data ☆ is shown in FIG. In the following description, the circled characters 1 and 2 shown in FIGS. 17A and 17B are described by substituting (1) and (2).

  17 (a) and 17 (b), in response to the input of the gamut compression destination p4 ′ for p4, the point calculation means 105 divides (1): Wp2 to p4, (2): p4 to Bp2. The distances D01 to D78 between the points in the line segment are calculated. Similarly, the linearized polyline is divided by p4 ′ (1) ′: Wp3 to p4 ′, (2) ′: Mapping is performed so as to preserve the distance ratio in two regions p4 ′ to Bp3, and p1 ′. ~ P7 'is determined. FIG. 17C shows a mapping of this to a polygon.

  According to the present embodiment described above, the gamut compression destination of the highest saturation point between the brightness of the white point and the black point is divided into two upper and lower regions, so that the output gamut can be utilized to the maximum and high saturation can be achieved. The point reproduction density can be made variable.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this. The present invention is not limited to the above-described embodiment, and is particularly suitable for application to a color conversion device such as a color facsimile, a color printer, and a color hard copy, and software for a color printer that operates on a workstation.

  Further, the control operation in each means constituting the color profile creation device in the above-described embodiment can be executed using hardware, software, or a combined configuration of both.

  In the case of executing processing using software, it is possible to install and execute a program in which a processing sequence is recorded in a memory in a computer incorporated in dedicated hardware. Alternatively, the program can be installed and executed on a general-purpose computer capable of executing various processes.

  For example, the program can be recorded in advance on a hard disk or ROM (Read Only Memory) as a recording medium. Alternatively, the program can be stored (recorded) temporarily or permanently in a removable recording medium. Such a removable recording medium can be provided as so-called package software. The removable recording medium includes a floppy (registered trademark) disk, a CD-ROM (Compact Disc Read Only Memory), an MO (Magneto optical) disk, a DVD (Digital Versatile Disc), a magnetic disk, a semiconductor memory, and the like.

  The program is installed in the computer from the removable recording medium as described above. In addition, it is wirelessly transferred from the download site to the computer. In addition, it is transferred to the computer via a network by wire.

It is a figure for demonstrating the color gamut conversion method applicable to embodiment of this invention. It is a figure for demonstrating the color gamut conversion method applicable to embodiment of this invention. FIG. 3 is a diagram for supplementarily explaining the color gamut conversion method of FIG. 2. It is a block diagram which shows the structure of the color gamut conversion apparatus which concerns on embodiment of this invention. It is a flowchart which shows operation | movement of the color gamut conversion apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the data which gamut data DB100 shown in FIG. 4 preserve | saves. It is a figure for demonstrating the point group selection which concerns on embodiment of this invention. It is the figure which plotted the 2nd gamut of the selected point group in CIELA color space. It is a figure for demonstrating the point-to-point data which concern on embodiment of this invention. It is a figure for demonstrating the polyline production | generation means 106 shown in FIG. It is the figure which accumulated FIG. 8 and FIG.9 (c). It is a figure for demonstrating the inside / outside determination which concerns on embodiment of this invention. It is a figure for demonstrating the result of the gamut compression which concerns on embodiment of this invention. It is a block diagram which shows the structure of the color gamut conversion apparatus which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the color gamut conversion apparatus which concerns on the 2nd Embodiment of this invention. It is a figure for demonstrating the calculation between points which concerns on the 2nd Embodiment of this invention. It is a figure for demonstrating the point cloud data which concern on the 2nd Embodiment of this invention.

Explanation of symbols

100 gamut data DB
DESCRIPTION OF SYMBOLS 101 Input gamut data storage means 102 Output gamut data storage means 103 Point group specification means 104 Output gamut determination means 105 Point calculation means 106 Polyline generation means 107 Polyline formation means 108 Color profile generation means

Claims (8)

Gamut designation means for designating an input gamut and an output gamut from a plurality of gamuts,
Gamut compression means for gamut compressing from the specified input gamut to the output gamut;
A color profile creating apparatus comprising:   The plurality of gamuts include a first gamut represented by an arbitrary color system, a second gamut of a virtual device, and a third gamut of a color image output apparatus. Color profile creation device. Point cloud designating means for designating a point cloud from the input gamut;
Inside / outside determination means for performing inside / outside determination of a specified point group for the output gamut;
As a result of the inside / outside determination, feature amount calculation means for calculating a feature amount from a point group determined externally, and
The color profile creation apparatus according to claim 1, wherein the gamut compression unit performs gamut compression using the calculated feature amount.   4. The color profile creation apparatus according to claim 3, wherein the point group designating unit designates a point group having substantially the same hue.   5. The color profile creation apparatus according to claim 3, wherein the point group designating unit designates a point group including a white point and a black point of the input gamut. Coordinate designating means for designating coordinates of the output gamut for at least one point of the point group designated by the point group designating means;
Feature amount calculation range dividing means for dividing the feature amount calculation range of the specified point group using specified coordinates,
The color profile according to any one of claims 3 to 5, wherein the feature amount calculating unit calculates a feature amount using the feature amount calculation range divided by the feature amount calculation range dividing unit. Creation device. A gamut specifying step for specifying an input gamut and an output gamut from a plurality of gamuts;
A gamut compression step for gamut compression from the specified input gamut to the output gamut;
A color profile creating method characterized by comprising: In the color profile creation device,
A gamut designation process for designating an input gamut and an output gamut from a plurality of gamuts;
Gamut compression processing for gamut compression from the specified input gamut to the output gamut;
A recording medium on which a program for executing the program is recorded.

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