JP2005106607A - Color managing system and color management method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color management system for determining a correcting expression for accurately correcting the differences between a reference value and measurement values of a plurality of color measuring meters for measuring the output from an image output apparatus disposed at each site so as to properly implement color management of a plurality of the image output apparatuses disposed at the sites, and a color management method for the system. <P>SOLUTION: A correction expression deriving part 1c separates the measurement values in a predetermined color system of a color chart P, by the color measuring meters S1-S3 into a plurality of regions as divided color space of the predetermined color system, uses a plurality of calculation techniques, and derives a plurality of the correcting expressions for approximating the separated measurement values to a measurement value of the color chart P by a reference color measuring meter S0. A selecting part 1e selects the correcting expression, having the best correcting accuracy among a plurality of the correcting expressions, based on color differences the reference value and the measurement values of the color chart P by the color-measuring meters S1-S3 corrected at the separated measurement values by a plurality of the correction expressions. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides a plurality of colorimeters that measure the output matter arranged at each site and output from the image output device in order to appropriately perform color management of the plurality of image output devices installed at each site. The present invention relates to a color management system and a color management method for deriving a correction formula for correcting a difference between a measured value and a reference value, and more particularly to a technique for determining a correction formula having high correction accuracy.

  For example, in an output device such as a color proof creation device that outputs a color proof in order to check the finished product in advance, it is installed at multiple remote locations for the purpose of color proofing the output color proof. It may be required to output the same output in the output device.

  In such a case, it is necessary to perform color management of the output devices, specifically, calibration so that the colors and densities of the output products output from the output devices at each site are matched.

At this time, at each site, the color and density of the output product output from the output device (for example, L ^* value, a ^* value, b ^* value in the CIE L ^* a ^* b ^* color system, XYZ color specification, etc.) An output device that measures the tristimulus values of X, Y, and Z in the system with a colorimeter (for example, a color difference meter) and approximates the color and density of the output product to a reference value based on the measured value Work to adjust.

  However, since a separate colorimeter is usually used at each site, for example, when the manufacturer or model of the colorimeter is different, the measured value is not necessarily due to the difference in the product or model. The problem of mismatching arises. For example, even if the manufacturer and model of the colorimeter are the same, there is a problem that the measured values do not always match due to individual differences.

  Thus, various methods have been proposed for correcting the difference in measured values among a plurality of colorimeters.

  For example, the color value correcting apparatus described in Japanese Patent Laid-Open No. Hei 6-281501 includes color value correcting means configured by a neural network that obtains the color value exhibited by the color measuring apparatus, and the correcting means analyzes spectral distribution. A technique (for example, see Patent Document 1) is described in which correction is performed at a spectral level and measurement values are adjusted between different colorimetric devices.

  Further, for example, in the colorimetric value correction method and colorimeter described in Japanese Patent Application Laid-Open No. 11-132849, the colorimetric value is a color value composed of three elements. When a secondary correction formula is created from the colorimetric value difference from, and the colorimetric value is corrected for each element using the correction formula, an appropriate correction formula can be used for each element. A technique (for example, see Patent Document 2) that corrects this with high accuracy has been proposed.

JP-A-6-281501 (paragraphs [0011]-[0036], FIGS. 1 to 5) Japanese Patent Laid-Open No. 11-132849 (paragraphs [0015]-[0050], FIGS. 1 to 5)

  However, in the former technique, a complicated calculation is performed using a neural network or the like, so that there is a problem that a high-performance large-scale computer is required and troublesome work such as learning is required. Further, in the latter technique, when the same type of colorimeter is used at each site, the difference in measured values resulting from the individual differences is accurately corrected depending on the above-described secondary correction formula for each element. There is a problem that you can't.

  That is, under such circumstances, each site can measure the color and density of the output output from the output device with a colorimeter, and adjust the output device based on the measured value. Since the difference between the measured values of the colorimeters at the base is not properly corrected, it is difficult to properly manage the colors of those output devices.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to arrange the image arranged at each site so as to appropriately perform color management of a plurality of image output apparatuses installed at each site. Color management system capable of determining a correction formula with a high correction accuracy as a correction formula for correcting a difference from a reference value of a measurement value of a plurality of colorimeters that measure an output product output from an output device, and its color To provide a management method.

  In order to solve the above-described problem, the invention according to claim 1 is an output product arranged at each base and output from the image output apparatus in order to perform color management of a plurality of image output apparatuses installed at each base. A color management system for deriving a correction formula for correcting a difference based on a difference between a measurement value of a plurality of colorimeters that perform measurement of the colorimetry, the color management system being arranged for each of the bases, Measured by a plurality of terminal devices having color sample measurement value transmitting means for transmitting measured values in a predetermined color system at a plurality of measurement points of the color sample measured by the colorimeter, and a reference colorimeter Color sample measurement value storage means for storing in advance a measurement value in a predetermined color system at a plurality of measurement points of the color sample as the reference value, and a plurality of the color samples transmitted from the color sample measurement value transmission means Measured value in the specified color system at the measurement point A color sample measurement value receiving means for receiving, and dividing the received measurement value into the regions obtained by dividing the color space in the predetermined color system into a plurality of regions, and for each of the divided measurement values, the measurement Correction formula deriving means for deriving a plurality of correction formulas for performing correction to approximate the value to the stored reference value, and for each of the divided measurement values, the measurement values are corrected by the plurality of derived correction formulas. Then, based on the measurement values corrected by the plurality of correction formulas, a correction formula determining means for determining a correction formula with the highest correction accuracy from the plurality of derived correction formulas, and the divided measurement values A management server having correction formula registration means for registering the determined correction formula as a correction formula for correcting the difference.

  In order to solve the above-described problem, the invention according to claim 6 is an output product arranged at each site and output from the image output device so as to perform color management of a plurality of image output devices installed at each site. A color management method for deriving a correction formula for correcting a difference based on a difference from a reference value of a measurement value of a plurality of colorimeters that perform measurement of the plurality of colorimeters. In the terminal device, a color sample measurement value transmission step for transmitting measurement values in a predetermined color system at a plurality of measurement points of the color sample measured by the colorimeter, and via the plurality of terminal devices and the network In a connected management server, a color sample measurement value storage step for storing in advance a measurement value in a predetermined color system at a plurality of measurement points of the color sample measured by a reference colorimeter as the reference value; , Color sample measurement A color sample measurement value receiving step of receiving measurement values in a predetermined color system at a plurality of measurement points of the color sample transmitted in the transmission step; and the received measurement values as colors in the predetermined color system Dividing the space into a plurality of regions divided into a plurality of regions, and deriving a correction equation for deriving a plurality of correction equations for performing correction for approximating the measured value to the stored reference value for each of the divided measured values Step, and for each of the divided measurement values, the measurement values are corrected by the plurality of derived correction expressions, and the plurality of derived corrections are performed based on the measurement values corrected by the plurality of correction expressions. A correction formula determining step for determining a correction formula with the highest correction accuracy from among the formulas, and a correction formula registration for registering the determined correction formula as a correction formula for correcting the difference for each of the divided measurement values Step Characterized in that it comprises a and.

  According to the color management system and the color management method according to the present invention, the correction formula deriving unit of the management server has a predetermined color specification at each measurement point of the color sample by the reference colorimeter stored in the storage unit. Based on the reference values of color and density in the system and the measured values of color and density in a predetermined color system at each measurement point of the color sample by the colorimeter arranged at each base received by the receiving unit The color space in the predetermined color system is divided into a plurality of areas, and the color and density in the predetermined color system at each measurement point of the color sample by the colorimeter arranged at each base for each of the plurality of areas. The measurement values are classified, and for each of the classified measurement values, correction is performed by approximating the color sample and density measurement values of the color sample by the colorimeters arranged at each base to a reference value by using a plurality of calculation methods. In order to derive a plurality of correction formulas for the calculation unit, For each measurement value, the color difference between the measurement value of the color sample and the color sample and the reference value by the colorimeter arranged at each base corrected by the plurality of correction formulas and the reference value is calculated. For each divided measurement value, select the one with the smallest average value or maximum value as the correction equation with the highest correction accuracy, and the registration unit sets the correction equation for each of the above-mentioned divided measurement values. Since it is registered as a correction formula for correcting the difference between the measurement value obtained by the colorimeters arranged at each base and the reference value, the management server registers the above-mentioned predetermined value to which the measurement values obtained by the colorimeters arranged at each base belong. In addition, it is possible to determine a correction equation that can perform accurate correction according to the color space region in the color system of the color system, and at the user's site, the correction equation for each of the divided measurement values Output from the output device while referring to By measuring this color and density and correcting this based on the correction formula corresponding to the divided area of the color space in the predetermined color system to which the measured value belongs, the difference from the reference value is obtained. In addition, by adjusting the output color and output density of the output device based on the corrected measurement value, the color management of the output device installed at its base can be appropriately performed. .

  In addition, according to the color management system and the color management method according to the present invention, the user can perform the above-described partitioned measurement registered in the registration unit of the management server by the reception unit of the terminal device arranged at his / her base. Since the information about the correction formula for each value is received and the received information about the correction formula for each of the above-mentioned classified measurement values can be displayed by the display unit, it is possible to display the management server without going to the installation location. , You can refer to this, efficiently correct the measurement value of the colorimeter placed at your base, adjust the output device based on the corrected measurement value, Color management of the installed output device can be performed.

  Hereinafter, a color management system and a color management method thereof according to the present invention will be specifically described with reference to the drawings.

[Configuration of color management system]
First, the configuration of the color management system in the present embodiment will be described in detail with reference to the drawings.

(Schematic configuration of color management system)
FIG. 1 shows a system configuration of the color management system. As shown in FIG. 1, the color management system includes colorimeters S1 to S3 that measure colors and densities of output products output from output devices C1 to C3 installed at a plurality of remote locations. A plurality of correction formulas for correcting the difference between the measured value of the color and the measured value by the reference colorimeter S0 are derived, and the colorimeters of the output objects output from the output devices C1 to C3 by the plurality of correction formulas Correcting the measurement values of S1 to S3, determining a correction formula with the highest correction accuracy based on the color difference between the corrected measurement values and the measurement value of the reference colorimeter S0, and correcting the correction formula The management server 1 for registering the formula and the colorimeters S1 to S3 are arranged in correspondence with each other, and the measurement values from the colorimeters S1 to S3 are transmitted to the management server 1 and registered in the management server 1 described above. Received the correction formula, A plurality of terminal devices 2a~2c for displaying, hints constructed.

  The terminal devices 2a to 2c may be arranged in an arbitrary number according to the number of colorimeters S1 to S3. Further, the output devices C1 to C3 and the colorimeters S1 to S3 may be different products or models. The output devices C1 to C3 may be output devices capable of adjusting color and density, such as printers and copiers, in addition to the color proof creating device.

(Detailed configuration of management server)
Here, a detailed configuration of the management server 1 will be described. The management server 1 is a so-called computer terminal, and includes display means such as a monitor, input means such as a keyboard and a mouse, and an apparatus main body including the server. Further, this apparatus main body is in a predetermined color system at each measurement point of a color chart for correcting a colorimeter (corresponding to “color sample” of the present invention) P measured by a reference colorimeter S0. A storage unit 1a for storing color and density measurement values as reference values in advance, and output products output from the output devices C1 to C3 by the colorimeters S1 to S3 transmitted from the terminal devices 2a to 2c (" Corresponding to the output product) and the colorimetric correction color chart P, the receiving unit 1b for receiving measured values of color and density in a predetermined color system at each measurement point, and the receiving unit 1b The color space in the predetermined color system described above is divided into a plurality of regions for the color and density measurement values in the predetermined color system at each measurement point of the color chart P for colorimeter correction by the colorimeters S1 to S3. Divided into the corresponding areas, and divided For each fixed value, a plurality of correction formulas for correcting the measurement value to approximate the color and density reference values of the colorimeter correction color chart P stored in the storage unit 1a by a plurality of types of calculation methods described later. For the correction formula deriving unit 1c to be derived, and for the colorimeter correction by the colorimeters S1 to S3 corrected based on a plurality of correction formulas derived by the correction formula deriving unit 1c for each of the above-described divided measurement values A calculation unit 1d for calculating a color difference between the color and density measurement values of the color chart P and the color and density reference values of the colorimeter correction color chart P stored in the storage unit 1a; For each value, based on the color difference calculated by the calculation unit 1d, the selection unit 1e that selects the correction equation with the highest correction accuracy from among a plurality of correction equations derived by the correction equation deriving unit 1c, For each measured value, The correction formula selected by the selection unit 1e is used for the colorimetry stored in the storage unit 1a as the color and density measurement values of the color chart P for colorimetry correction by the colorimeters S1 to S3 received by the reception unit 1b. The registration unit 1f registered as a correction formula for performing correction to approximate the reference value of the color and density of the meter correction color chart P, and the correction formula for each of the divided measurement values registered in the registration unit 1f And a transmission unit 1g for transmitting information on the terminal devices 2a to 2c.

  The storage unit 1a includes storage means such as a memory and corresponds to the “color sample measurement value storage means” of the present invention. The reception unit 1b and the transmission unit 1g are configured by a network I / F, and correspond to the “color sample measurement value reception unit” and the “correction type transmission unit” of the present invention, respectively. Further, the correction formula deriving unit 1c, the calculating unit 1d, the selecting unit 1e, and the registering unit 1f are configured by a calculation unit such as a CPU and a storage unit such as a memory. By executing a stored predetermined arithmetic program, processing described later is performed. These correspond to the “correction formula derivation means”, “calculation means”, “correction formula selection means”, and “correction formula registration means” of the present invention, respectively. Incidentally, the correction formula deriving unit 1c and the selection unit 1e constitute the “correction formula determining means” of the present invention.

(Configuration of color chart for colorimeter correction)
Here, the configuration of the colorimeter P for colorimeter correction described above will be described. The color chart P for colorimeter correction corresponds to the “color sample” of the present invention. Specifically, as shown in FIG. 2, for example, C100%, M100%, Y100%, K100%, Each color covering each region of the color space in a predetermined color system such as CMY100%, MY100%, etc. is arranged in a horizontal row, and each constitutes one measurement point (in the figure, 17 measurements are shown). Composing points). That is, in the reference colorimeter S0 and the colorimeters S1 to S3, the same measurement point among these plurality is measured in the same measurement order (for example, along the arrow direction shown in the figure). Become.

  The color chart P for colorimeter correction is created by a heat melting type high-end DDCP (Direct Digital Color Proof, a system that directly outputs digital data to a high-precision printer) with little color variation over time. It is preferable.

(Detailed configuration of terminal device)
Here, the detailed configuration of the terminal devices 2a to 2c will be described. However, since the terminal devices 2a to 2c have the same configuration, the following description will be given taking the terminal device 2a as an example.

  The terminal device 2a is a so-called computer terminal, and an interface for inputting measured values of color and density in a predetermined color system at each measurement point of the color chart P for colorimeter correction by the colorimeter S1. (I / F) is an input unit 2aa, a transmission unit 2ab that transmits the measurement value of the colorimeter S1 input via the input unit 2aa to the management server 1 via the network N, and the management server 1 The receiving unit 2ac that receives the correction formula transmitted from the transmitting unit 1g, that is, the information related to the correction formula for each of the divided measurement values registered in the registration unit 1f of the management server 1, and received by the receiving unit 2ac And a display unit 2ad for displaying information related to the correction formula for each of the divided measurement values described above.

  The input unit 2aa is configured by input means such as a keyboard and a mouse. The transmission unit 2ab and the reception unit 2ac are configured by a network I / F and correspond to the “color sample measurement value transmission unit” and the “correction type reception unit” of the present invention, respectively. The display unit 2ad is composed of display means such as a monitor and corresponds to the “correction type display means” of the present invention.

[Color management method]
Here, the color management method performed in the color management system described above will be described along the flow of the flowcharts shown in FIGS. 3 to 5 with reference to FIGS. However, in the following, description will be given by taking as an example a case where the measurement value correction by the colorimeter S1 is performed and the calibration relating to the output device C1 is performed.

[Color sample measurement value storage step]
The administrator of the management server 1 measures the color and density of the colorimeter P for colorimeter correction described above according to the position of the predetermined measurement point and the measurement order using the reference colorimeter S0. Thereby, the measured values of the color and density in a predetermined color system at each measurement point of the color chart P for colorimeter correction are measured.

  Next, the administrator uses the management server 1 to obtain measured values of color and density in a predetermined color system at each measurement point of the color chart P for colorimeter correction measured by the reference colorimeter S0. The input is performed by input means such as a keyboard or a mouse, or by registration of a file storing measurement values. However, at this time, information on the position and measurement order of each measurement point on the color chart P for colorimeter correction is also input. Thereby, the measured values of the color and density in a predetermined color system at each measurement point of the color chart P for correcting the colorimeter, together with information on the position and measurement order of those measurement points, a reference to be described later of the storage unit 1a. It is stored in the measuring instrument measurement data table as reference measuring instrument measurement data.

  On the other hand, a user who uses the color management system registers color and density measurement values in a predetermined color system at each measurement point of the color chart P for colorimetry correction by the colorimeter S1 in the terminal device 2a. Work to do. Specifically, first, by accessing the management server 1 from the terminal device 2a, for example, on a screen displayed on a predetermined site on the Web, a predetermined item, specifically, measurement of the colorimeter S1 is performed. Input information (e.g., address, name, phone number, etc.) of the mailing address of the color chart P for colorimeter correction that is the object.

  In response to this, the administrator checks the predetermined items on the screen displayed on the predetermined site on the Web described above in the management server 1, and corrects the colorimeter to the designated mailing address. Work for mailing the color chart P for mail.

  On the other hand, when the color chart P for colorimeter correction arrives, the user connects the colorimeter S1 to the input unit 2aa of the terminal device 2a by communication means such as a communication cable, and then connects the terminal device 2a to the management server 1. Access and download the measurement tool on the tool screen displayed on the Web page. The measurement tool refers to information on the position and measurement order of each measurement point on the color chart P for colorimeter correction measured by the reference colorimeter S0, and also the colorimeter by the colorimeter S1. It includes information on a transmission destination for transmitting measurement values of color and density in a predetermined color system at each measurement point of the correction color chart P, and the measurement tool performs measurement via the terminal device 2a. After being downloaded to the colorimeter S1, the colorimeter S1 measures the measurement points at the same positions as those by the reference colorimeter S0 in the same measurement order. The measurement tool may be stored in a storage medium such as a CD-ROM and downloaded to the colorimeter S1 via the terminal device 2a.

[Color sample measurement value transmission step]
As shown in FIG. 3, when the user measures colors and densities in a predetermined color system at each measurement point of the color chart P for colorimeter correction with the colorimeter S1 in this way (S01), The measured value is transmitted to the terminal device 2a via the input unit 2aa (S02). At this time, measured values of color and density in a predetermined color system at each measurement point of the color chart P for colorimeter correction are measurement screens displayed on the display means of the terminal devices 2a to 2c, specifically, In the measurement value display field 10Aa of the color chart measurement screen 10A for colorimeter correction as shown in FIG. 6, for example, the L ^* value, a ^* value, and b ^* value in the CIE L ^* a ^* b ^* color system Is displayed.

  Next, on the color chart measurement screen 10A for colorimeter correction, the user selects the transmission button by operating the input means, thereby transmitting the information to the management server 1 from the transmission unit 2ab of the terminal device 2a. Operation is performed (S03).

  As shown in FIG. 4, the transmission unit 2ab of the terminal device accesses the management server 1 and the display unit 2ad displays a login screen. Further, when the user performs a login operation on the login screen using the input means, the registration unit 1f of the management server 1 performs database authentication regarding the user of the terminal device 2a that has accessed the management server 1 (S07). That is, in the registration unit 1f, identification information regarding users who use the terminal devices 2a to 2c is stored as user information table, and user authentication is performed by referring to the user information table (S08) (S09). . Here, when the user is authenticated (S09, OK), the registration unit 1f refers to the setting information stored in the session information table (S10), and is authenticated by the user according to the setting information, that is, Then, a session is started with respect to the terminal device 2a (S11).

[Color sample measurement value reception step]
In response to this, the transmission unit 2ab of the terminal device 2a sends the measurement values of the color and density in a predetermined color system at each measurement point of the color chart P for colorimeter correction by the colorimeter S1 to the management server 1. Then, in the management server 1, the receiving unit 1b receives this and stores it in the user measuring instrument measurement data table of the storage unit 1b. Here, the storage unit 1b stores correction information for correcting a difference in measured values due to a product difference or a model difference between the colorimeter S0 and the colorimeters S1 to S3 serving as a reference in the user measuring device information table. The measured values of color and density in a predetermined color system at each measurement point of the color chart P for colorimetry correction by the colorimeter S1 stored in the user measuring instrument measurement data table are stored in the user measuring instrument information table. Is stored as corrected measurement data after the user measuring instrument in which the difference between the measured values due to the product difference and the model difference from the reference colorimeter S0 is corrected.

[Correction formula derivation step]
In response to this, the correction formula deriving unit 1c acquires the user measurement device corrected measurement data stored in the storage unit 1a and the reference measurement device measurement data stored in the reference measurement device measurement data table of the storage unit 1a. (S12), the obtained measurement data after correction by the user measuring instrument, that is, measured values of color and density in a predetermined color system at each measurement point of the color chart P for colorimetry correction by the colorimeter S1, After dividing the color space in the predetermined color system into a plurality of areas, specifically, as shown in FIG. 7, for example, colors in the CIE L ^* a ^* b ^* color system a plurality of regions of space, ^{a *} × ^{b *} 2 a region of "+ ^{a *} region" and "-a ^* region" in space, further ^{a *} × ^{b *} in space ^"+ a ^*, + ^b * region" and "+ a ^*, -b ^* area "and" ^-a *, + b Region "and" -a ^*, is divided in four regions of -b ^* areas ", for each measurement value of the segment the each area, each measurement colorimeter correcting the color chart P by colorimeter S1 The measured values of the color and density in a predetermined color system at the point are used as the obtained reference measuring instrument measurement data, that is, the predetermined measurement point at each measurement point of the color chart P for colorimeter correction by the reference colorimeter S0. A plurality of correction formulas for correcting to approximate the reference values of the color and density in the color system are derived by a plurality of types of calculation methods (S13).

At this time, the correction formula deriving unit 1c, for example, uses CIE (Commission Internationale de l'Eclairage: International Lighting Commission) L ^* a ^* b ^* measured values expressed in the color system XYZ (tristimulus values). It is preferable to derive the above-described plurality of correction expressions after conversion into measurement values expressed in a color system. This is because in the XYZ (tristimulus value) color system, the measurement value can always be expressed as a positive value, and it becomes easy to correct the measurement value. However, depending on the configuration of the colorimeter S1, the measurement value may be calculated in an XYZ (tristimulus value) color system, and in such a case, the above-described conversion need not be performed.

(Details of conversion method)
Here, the details of the method for converting the measured values from the above-mentioned CIE (Commission Internationale de l'Eclairage: International Lighting Commission) L ^* a ^* b ^* color system to the XYZ (tristimulus value) color system are specifically described. I will explain it.

Conversion formula from L ^* a ^* b ^* color system to XYZ (tristimulus value) color system For example, when a D50 light source (standard color temperature in the printing industry (5000K)) is used, (L, a, b) and Between (X, Y, Z)
y = (L + 16.0) /116.0
x = a / 500.0 + y
z = y−b / 200.0
The following relational expression holds.
Here, when xs0, ys0, zs0> 0.008856,
xs0 = ^{x 3}
ys0 = ^{y 3}
and zs0 = ^{z 3,}
In addition, when xs0, ys0, zs0 ≦ 0.008856,
xs0 = [x- (16.0 / 116.0)] / 7.787
ys0 = {y− (16.0 / 116.0)} / 7.787
zs0 = [z- (16.0 / 116.0)] / 7.787
As
X = xs0 × 0.98072
Y = ys0 × 1.00000
Z = zs0 × 1.18225
Substituting into, each element of X, Y, Z is appropriately expressed by the values of L, a, b.

(Specific examples of multiple calculation methods)
Next, specific examples of a plurality of calculation methods used when the above-described correction formula deriving unit 1c derives a plurality of correction formulas will be described.

  The correction formula deriving unit 1c includes, for example, various calculations described below, including the calculation method disclosed in Japanese Patent Laid-Open No. 11-132849 (paragraphs [0015]-[0050], FIGS. 1 to 5). A plurality of correction formulas are derived by the method.

Example 1) Method for obtaining coefficients (α, β, γ) of quadratic function by regression analysis First, color chart P for colorimeter correction by colorimeter S0 serving as a reference for each element of X, Y, Z Color and density reference values (measured values expressed in the L ^* a ^* b ^* color system converted to measured values expressed in the XYZ color system) and the colorimeter S1 The difference from the measured values of color and density of the correction color chart P (measured values expressed in the L ^* a ^* b ^* color system are converted into measured values expressed in the XYZ color system) 8A and 8B, for each measurement point, the horizontal axis represents the measured value by the colorimeter S1 and the vertical axis represents the difference from the measured value by the reference colorimeter S0. A graph is created by plotting, and an approximate curve of the measured value difference for each element is calculated. This approximate curve is represented by Xu, Yu, Zu as measured values by the colorimeter S1, and Dx (Xu), Dy (Xu), Dz (Zu) as differences from the measured values by the reference colorimeter S0. It can be expressed as follows:

Part 1: An approximation curve passing through the origin (corresponding to FIG. 8A)
Dx (Xu) = Xs−Xu = α (Xu + β) ²
Dy (Yu) = Ys−Yu = α (Xu + β) ²
Dz (Zu) = Zs−Zu = α (Xu + β) ²
Here, α and β are coefficients in the same sample measurement.

2: The approximate straight line does not necessarily pass through the origin (corresponding to FIG. 8B)
Dx (Xu) = Xs−Xu = αXu ² + βXu + γ
Dy (Yu) = Ys−Yu = αYu ² + βYu + γ
Dz (Zu) = Zs−Zu = αZu ² + βZu + γ
Here, α, β, and γ are coefficients in the same sample measurement.

  For the above approximate curve, the values of α, β, and γ are obtained by the least square method for each element of X, Y, and Z, and correction that becomes a function of Xs, Ys, and Zs following Xu =, Yu =, and Zu = Derive an expression.

ここで、Ｘｓ、Ｙｓ、Ｚｓは、基準となる測色計Ｓ０による測色計補正用カラーチャートＰの色彩や濃度の基準値であり、Ｘｕ、Ｙｕ、Ｚｕは、測色計Ｓ１による測色計補正用カラーチャートＰの色彩や濃度の測定値である。また、ａ００〜ａ２２は、同一のサンプル測定における係数である。 Example 2) Method for obtaining 3 × 3 matrix coefficients (a00 to a22) in regression analysis Part 1: No intercept

Here, Xs, Ys, and Zs are reference values for the color and density of the color chart P for correcting the colorimeter by the reference colorimeter S0, and Xu, Yu, and Zu are the colorimetric values by the colorimeter S1. This is a measured value of color and density of the color chart P for meter correction. Further, a00 to a22 are coefficients in the same sample measurement.

ここで、Ｘｓ、Ｙｓ、Ｚｓは、基準となる測色計Ｓ０による測色計補正用カラーチャートＰの色彩や濃度の基準値であり、Ｘｕ、Ｙｕ、Ｚｕは、測色計Ｓ１による測色計補正用カラーチャートＰの色彩や濃度の測定値であり、ａ００〜ａ２２は、同一のサンプル測定における係数であり、ｂ１〜ｂ３は、同一のサンプル測定における定数である。 Part 2: There is a section

Here, Xs, Ys, and Zs are reference values for the color and density of the color chart P for correcting the colorimeter by the reference colorimeter S0, and Xu, Yu, and Zu are the colorimetric values by the colorimeter S1. It is a measurement value of the color and density of the color chart P for meter correction, a00 to a22 are coefficients in the same sample measurement, and b1 to b3 are constants in the same sample measurement.

  For each of the above formulas, the values of a00 to a22 and b1 to b3 are obtained by regression analysis for each element of X, Y, and Z, and the following correction formula is derived.

Part 1: No section

Part 2: With a section

Example 3) Method of obtaining coefficient (α, β) of linear function by regression analysis First, the color of the color chart P for colorimeter correction by the colorimeter S0 as a reference for each element of X, Y, Z And density reference values (measured values expressed in L ^* a ^* b ^* color system converted to measured values expressed in XYZ color system) and colorimeter correction by colorimeter S1 Find the difference from the measured values of color and density of the color chart P (measured values expressed in L ^* a ^* b ^* color system converted to measured values expressed in XYZ color system) As shown in FIGS. 9A and 9B, the measured value obtained by the colorimeter S1 is plotted on the horizontal axis and the difference from the measured value obtained by the reference colorimeter S0 is plotted on the vertical axis for each measurement point. A graph is created and an approximate straight line of the measured value difference for each element is calculated. The approximate straight line is represented by Xu, Yu, Zu as measured values by the colorimeter S1, and Dx (Xu), Dy (Xu), and Dz (Zu) as differences from the measured values by the reference colorimeter S0. It can be expressed as follows:

Part 1: An approximate straight line passing through the origin (corresponding to FIG. 9A)
Dx (Xu) = Xs−Xu = αXu
Dy (Yu) = Ys−Yu = αYu
Dz (Zu) = Zs−Zu = αZu
Here, α is a coefficient in the same sample measurement.

2: The approximate straight line does not necessarily pass through the origin (corresponding to FIG. 9B)
Dx (Xu) = Xs−Xu = αXu + β
Dy (Yu) = Ys−Yu = αYu + β
Dz (Zu) = Zs−Zu = αZu + β
Here, α and β are coefficients in the same sample measurement.

For the approximate straight line, the values of α and β are obtained by the least square method for each element of X, Y, and Z, and the following correction formula is derived.
Part 1: An approximate straight line passing through the origin (corresponding to FIG. 9A)
Xu = Xs / (α + 1)
Yu = Ys / (α + 1)
Zu = Zs / (α + 1)
The two approximate straight lines do not necessarily pass through the origin (corresponding to FIG. 9B).
Xu = (Xs−β) / (α + 1)
Yu = (Ys−β) / (α + 1)
Zu = (Zs−β) / (α + 1)

[Correction formula determination step]
As shown in FIG. 5, in the management server 1, the calculation unit 1 d further includes a colorimeter correction color by the colorimeter S <b> 1 corrected by the plurality of correction formulas for each of the divided measurement values. The measured values of the color and density in a predetermined color system at each measurement point of the chart P, and the predetermined color system at each measurement point of the color chart P for colorimeter correction by the colorimeter S0 serving as a reference. The color and density measurement values are converted again to values expressed in the CIE L ^* a ^* b ^* color system, and then measured by the colorimeter S1 corrected by the above-described plurality of correction equations. Measured values of color and density in a predetermined color system at each measurement point of the color correction chart P for color correction and a predetermined table at each measurement point of the color chart P for colorimetry correction by the reference colorimeter S0 ΔE = {(, which is the color difference from the color and density reference values in the color system ^{L *) 2 + (Δa *} ) 2 + (Δb *) 2} 1/2 value, and further, the average value in each of these measurement points (average ΔE value), or, calculating a maximum value (maximum ΔE value) Then (S14, calculation step), the selection unit 1e selects the correction formula that minimizes the average ΔE value or the maximum ΔE value as the correction formula with the highest correction accuracy (S15, correction formula selection step). Incidentally, in actuality, when Example 2) and Example 3) are compared, if the reference colorimeter S0 and the colorimeters S1 to S3 are different products or models, Example 3) is used. The correction formula tends to improve the correction accuracy. On the other hand, when the reference colorimeter S0 and the colorimeters S1 to S3 are the same product or model, the correction formula according to Example 2) tends to improve the correction accuracy.

(Specific example of correction formula determination)
Here, details will be described in which the average ΔE value and the maximum ΔE value are calculated by the calculation unit 1d described above, and the correction formula with the highest correction accuracy is selected by the selection unit 1e.

FIG. 10 shows an example of the average ΔE value and the maximum ΔE value calculated by the calculation unit 1d. As shown in FIG. 10, in this example, the correction formula deriving unit 1c is a predetermined color system at each measurement point of the color chart P for colorimeter correction by the colorimeter S1 stored in the storage unit 1a. The measured values of color and density in the CIE L ^* a ^* b ^* color space are expressed in a plurality of areas of the color space, specifically, “+ a ^* area” and “−a ^* area” in the a ^* × b ^* space. in the two regions, ^{a *} × ^{b *} space ^"+ a ^*, + ^b * ^{region", "+ a *, -b} * ^{areas", "- a *, +} b * region" and ^"-a *, -b ^* The storage unit stores the measurement values of the color and density of the color chart P for the colorimeter correction by the colorimeter S1 for each of the measurement values divided into the four regions “region”. The color chart P for colorimeter correction by the reference colorimeter S0 stored in 1a A correction formula for performing correction to approximate the reference value of the saturation and density is expressed by “the first method (intercept for obtaining a 3 × 3 matrix coefficient) (intercept”) in the above-described plural types of calculation methods, specifically, Example 2. None)) ”,“ No. 2 (Method for obtaining a matrix coefficient of 3 × 3 (with intercept)) ”,“ No. 1 (Method for obtaining a coefficient of a linear function (no intercept)) ”in Example 3),“ Color 2 for colorimeter correction by the colorimeter S1 derived by the calculation method “Part 2 (Method for obtaining coefficient of linear function (with intercept))” and calculated by the correction equation 1d. ΔE = {, which is the color difference between the measured value at each measurement point of the color and density of the chart P and the reference value at each measurement point of the color and density of the color chart P for colorimeter correction by the colorimeter S0 serving as a reference (ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² } ^1/2 values, and further, the case where the average ΔE value and the maximum ΔE value at each measurement point are calculated is taken as an example. However, in FIG. 10, for comparison purposes, the correction formula deriving unit 1 c also describes the average ΔE value and the maximum ΔE value at each measurement point in the conventional case where no region division is performed (no region division). It is. Incidentally, as shown in FIG. 10, when the area division is performed, the average ΔE value and the maximum ΔE value at each measurement point are the same as in the conventional case (no area division) in both of the two divisions and the four divisions. ) Can be confirmed to be smaller. That is, it can be confirmed that the correction accuracy is improved in each correction formula.

As described above, the correction formula deriving unit 1c selects, as the correction formula with the highest correction accuracy, the correction formula that minimizes either the average ΔE value or the maximum ΔE value calculated by the calculation unit 1d. Which of these is to be selected is basically set flexibly so that, for example, the one with the smallest maximum ΔE is selected, but the one with the smallest average ΔE is selected according to the situation. It is preferable. For example, as shown in FIG. 10, the measured values at each measurement point of the colorimeter P for colorimeter correction by the colorimeter S1 stored in the storage unit 1a are represented by colors in the CIE L ^* a ^* b ^* color system. When the space is divided into two areas, “+ a ^* area” and “−a ^* area”, in the a ^* × b ^* space, the variation of the average ΔE value in each correction method is 0.172 to 0.233. In such a case, the correction formula deriving unit 1c most corrects the “method for obtaining a 3 × 3 matrix coefficient (with an intercept)” in which the maximum ΔE value is minimum, that is, 0.777. The correction formula is selected with high accuracy. On the other hand, the measured value at each measurement point of the color chart P for colorimeter correction by the colorimeter S1 stored in the storage unit 1a is expressed as a color space in the CIE L ^* a ^* b ^* color system a ^* × b. ^* in space ^"+ a *, + ^{b *} region", ^"+ a *, -b ^{* areas", "- a *, +} b * region" and ^"-a *, -b ^* areas" case of dividing into four regions Since the variation of the average ΔE value in each correction method is relatively large as 0.166 to 0.299, the correction formula deriving unit 1c has the minimum ΔE value in this case, that is, 0.777. Is not selected as the correction formula with the highest correction accuracy, but the average ΔE value is the minimum, that is, 0.166, “3 × 3 matrix coefficient Correction method with the highest correction accuracy. Let's choose as.

  By performing such processing, for example, other measurement points are included in the measurement values of the color and density in a predetermined color system at each measurement point of the color chart P for colorimeter correction by the colorimeter S1. If some of the measured values are far away from each other, especially if the measured values are color measurements that are not very important for visual recognition, they are not affected by this. The correction formula with the highest correction accuracy can be selected.

[Correction formula registration step]
Returning to FIG. 5, next, in the management server 1, the registration unit 1 f uses the colorimeter S 1 to select the correction formula with the highest correction accuracy for each of the above-described divided measurement values selected by the selection unit 1 e. It registers as a correction formula for correcting the difference between the measured value and the reference value (S16). At this time, the registration unit 1f uses the correction value for each of the divided measurement values selected by the selection unit 1e as the reference value by the colorimeter S0 as a reference or the measurement value by the colorimeter S1. It is registered as being expressed in the XYZ (tristimulus value) color system. This is because, as described above, in the XYZ (tristimulus value) color system, the measurement value can always be expressed as a positive value, and the measurement value can be easily corrected.

[Correction type transmission step]
When the steps up to here are completed, in the management server 1, the transmission unit 1g registers the measurement value of the colorimeter S1 with the terminal device 2a. More specifically, the color for correcting the colorimeter by the colorimeter S1. While notifying that the registration of the correction formula for correcting the color and density measurement values of the chart P to the color and density reference values of the color chart P for colorimetry correction by the colorimeter S0 as a reference is completed, Information related to the above-described correction formula for each of the divided measurement values registered by the registration unit 1f is transmitted to the terminal device 2a (S17). Incidentally, at this time, for example, the correction formula deriving unit 1c performs the colorimeter correction color by the colorimeter S0 and the color and density measurement values of the colorimeter correction color chart P by the colorimeters S1 to S3. Only when the difference from the reference value of the color and density of the chart P is determined and the difference is larger than the specified value, the transmission unit 1g is registered by the registration unit 1f for each of the divided measurement values described above. Information regarding the correction formula may be transmitted to the terminal device 2a.

[Correction formula reception step], [Correction formula display step]
On the other hand, in the terminal device 2a, the notification that the reception unit 2ac has completed registration of the colorimeter S1 transmitted from the transmission unit 1g of the management server 1 and the correction formula for each of the divided measurement values described above. (S18), the display unit 2ad corrects the difference between the completion of registration of the colorimeter S1 and the reference value of the measurement value by the colorimeter S1. Information on the correction formula for each measurement value is displayed (S19).

  Here, the user refers to the information related to the above-described correction formula for each of the divided measurement values for correcting the difference from the reference value of the measurement value obtained by the colorimeter S1 displayed on the display unit 2ad. By correcting the measurement values of the color and density of the output object output from C1 by the correction formula for each of the above-mentioned divided measurement values corresponding to the color space region in the predetermined color system to which the measurement value belongs. The calibration of the output device C1 installed at its own base is performed by eliminating the difference from the reference value and further adjusting the output color and output density of the output device C1 based on the corrected measurement value. Can be performed properly.

  In addition, the user of each base performs the process demonstrated above similarly with respect to the colorimeter S2, the output device C2, the colorimeter S3, and the output device C3, and the colorimeter S1 arrange | positioned in all the bases. The difference between the measured values of S3 and the reference value can be eliminated, and the output devices C1 to C3 installed at all the bases can be properly calibrated. Thereby, in the output devices C1-C3 installed in each base, it becomes possible to output the output thing which has the same color and density | concentration.

As described above, according to the color management system and the color management method in the present embodiment, the correction formula deriving unit 1c of the management server 1 performs the measurement by the colorimeter S0 serving as the reference stored in the storage unit 1a. A reference value of the color and density in a predetermined color system at each measurement point of the color chart P for colorimeter correction, and the color chart P for correction of the colorimeter by the colorimeters S1 to S3 received by the receiver 1b. The colorimeters S1 to S3 are provided for each of the plurality of areas obtained by dividing the color space in the predetermined color system into a plurality of areas based on the measurement values of the color and density in the predetermined color system at each measurement point. The measured values of color and density in a predetermined color system at each measurement point of the color chart P for colorimeter correction by the colorimeter are classified, and the colorimeter is divided into a plurality of types of calculation methods for each of the classified measurement values. Colorimeter for colorimeter correction by S1 to S3 A plurality of correction formulas for deriving correction to approximate the color and density reference values of the color chart P for the colorimeter correction by the colorimeter S0 based on the measurement values of the color and density of the color chart P as a reference are derived. The calculation unit 1d performs colorimetric correction by the colorimeter S0 and the colorimetric correction values measured by the colorimeters S1 to S3 corrected by the plurality of correction formulas and the reference colorimeter S0. ΔE = {(ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² } ^½ value, which is the color difference from the color or density reference value of the color chart P, is selected by the selection unit 1e. The average value (average ΔE value) or the maximum value (maximum ΔE value) is selected as the correction formula with the highest correction accuracy, and the registration unit 1f selects the correction formula as the colorimeters S1 to S3. Between color and density measurement values and reference values of color chart P Since it is registered as a correction formula to be corrected, the management server 1 can perform accurate correction according to the color space area in the predetermined color system to which the measurement values obtained by the colorimeters S1 to S3 belong. The correction formula can be determined, and the user can measure the color and density of the output matter output from the output devices C1 to C3 while referring to the correction formula at each site, and the measurement value belongs to it. Based on the correction formula corresponding to the divided area of the color space in the predetermined color system described above, by correcting this, the difference from the reference value is eliminated, and further, the corrected measurement value is obtained. Based on the adjustment of the output colors and output densities of the output devices C1 to C3, the calibration of the output devices C1 to C3 installed at their bases can be appropriately performed.

  Further, according to the color management system and the color management method in the present embodiment, the user registers the registration unit 1f transmitted from the management server 1 by the reception unit 2ac of the terminal devices 2a to 2c arranged at his / her base. Can be received and information related to the received correction formula can be displayed on the display unit 2ad, so that it can be referred to without going to the location where the management server 1 is installed. The measurement values of the colorimeters S1 to S3 arranged at their bases can be corrected efficiently, and the output devices C1 to C3 are adjusted based on the corrected measurement values and installed at the bases of themselves. Calibration of the output devices C1 to C3 thus performed can be performed.

  The color management system and the color management method according to the present invention are not limited to the embodiment described above, and various modifications can be made without departing from the scope of the invention.

For example, in the color management system and the color management method in the above-described embodiment, the reference colorimeter S0 and the colorimeters S1 to S3 have measured values of CIE L ^* a ^* b ^* display system, or Although the calculation is performed by the XYZ display system, it may be calculated by, for example, the CIE L ^* u ^* v ^* display system.

Accordingly, in the color management system and the color management method in the embodiment described above, each measurement of color and density of the color chart P for colorimeter correction by the colorimeters S1 to S3 corrected by a plurality of correction formulas. The CIE L ^* a ^* b ^* color system is adopted as the color system for classifying the measured values at the points. As an example of an area for dividing the color space into a plurality of colors, for example, “+ a ^* in a ^* × b ^* space regions "and" -a ^* region "and two regions, ^{a *} × ^{b *} in ^space" + a ^*, + ^b * region ^{"," + a *, -b} * areas ^{"," - a *, +} b * region " and ^"-a *, -b ^* areas" has been given a case of dividing into four regions, in addition to this, for example, XYZ as a color system described above (tristimulus values) color system and CIE ^L * u ^* v ^* may be used as the adoption of the display system and the like, And, as an example of a region divided into a plurality of color spaces described above, for example, ^{L *} × ^{a *} in space "+ ^{L *} region" and "-L ^* region" two regions or, in the ^{L *} × ^{a *} space " + L ^* , + a ^* area ”,“ + L ^* , −a ^* area ”,“ −L ^* , + a ^* area ”and“ −L ^* , −a ^* area ”, or L ^* × a ^* × ^b in ^* space ^{"+ L *, + a *} , + b * ^{region", "+ L *, -a} *, + b * ^{region", "- L *, +} a *, + b * region", ^"- L *, -a ^* , + B ^* region "," + L ^* , + a ^* , -b ^* region "," + L ^* , -a ^* , -b ^* region "," -L ^* , + a ^* , -b ^* region "and"- It is also possible to divide into 8 regions such as “L ^* , −a ^* , −b ^* region”. Incidentally, it is conceivable to increase the correction accuracy of the derived correction formula by increasing the number of areas into which the color space is divided (ideally, by dividing the area for each measurement point). As a result, the correction formula deriving unit 1c and the calculation unit 1d of the management server 1 increase the load on the correction formula deriving process and the calculation process. In view of the processing capability, it is preferably set within an appropriate range, for example, about 2 to 8.

  Further, in the color management system and the color management method in the above-described embodiment, it has been described that the color chart P for colorimeter correction is preferably output by DCCP. It is good also as outputting by output devices, such as a copying machine.

  Further, in the color management system and the color management method in the above-described embodiment, the color chart P for the colorimeter correction includes a plurality of colorimeters S1 to S1 arranged at the respective locations, which are managed with the same color and density. Although it was decided to mail each to S3, in addition to this, one thing is made to circulate to colorimeter S1-S3. Alternatively, one item may be mailed to the colorimeters S1 to S3 each time and collected.

It is explanatory drawing which shows the system configuration | structure of the color management system which concerns on this invention. It is explanatory drawing which shows the structure of the color chart for colorimeter correction | amendment. 2 is a flowchart for explaining a series of flows of a color management method performed in a colorimeter and a terminal device of the color management system shown in FIG. 1. 2 is a flowchart for explaining a series of flow of a color management method performed in a management server of the color management system shown in FIG. 1. 2 is a flowchart for explaining a series of flows of a color management method performed in a management server and a terminal device of the color management system shown in FIG. 1. FIG. 2 is a configuration diagram illustrating a configuration of a correction color chart measurement screen displayed on the display unit in the terminal device of the color management system illustrated in FIG. 1. In the correction formula deriving unit of the management server shown in FIG. 1, the measurement values of the color and density in a predetermined color system at each measurement point of the color chart for colorimetry correction by the colorimeter are in the predetermined color system. It is explanatory drawing for demonstrating the process divided into the said area | region which divided | segmented color space into several area | region. (A) and (B) are explanatory diagrams for explaining a process in which a coefficient of a quadratic function as a correction formula is obtained by regression analysis in the correction formula derivation unit of the management server shown in FIG. . (A), (B) is explanatory drawing for demonstrating the process in which the coefficient of the linear function which is a correction formula is calculated | required by regression analysis in the correction formula derivation part of the management server shown in FIG. . In the calculation unit of the management server shown in FIG. 1, for each division pattern, the measured values of color and density in a predetermined color system at each measurement point of the color chart for colorimetry correction by the corrected colorimeter It is explanatory drawing for demonstrating the process in which the color difference with a reference | standard, a maximum color difference, and an average color difference are calculated.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Management server 1a Storage part 1b Reception part 1c Correction formula derivation part 1d Calculation part 1e Selection part 1f Registration part 1g Transmission part 2a-2c Terminal device 2aa Input part 2ab Transmission part 2ac Reception part 2ad Display part C1-C3 Output device N Network P Color chart for colorimeter correction S0 Standard colorimeter S1-S3 Colorimeter

Claims (10)

In order to perform color management of a plurality of image output devices installed at each site, a reference value of measurement values of a plurality of colorimeters that measure the output matter arranged at each site and output from the image output device; A color management system for deriving a correction formula for correcting the difference based on the difference of
A plurality of terminal devices each having a color sample measurement value transmitting means arranged at each of the sites and transmitting measurement values in a predetermined color system at a plurality of measurement points of the color sample measured by the colorimeter;
Color sample measurement value storage means for previously storing, as the reference value, measurement values in a predetermined color system at a plurality of measurement points of the color sample measured by a reference colorimeter, and transmitting the color sample measurement value Color sample measurement value receiving means for receiving measurement values in a predetermined color system at a plurality of measurement points of the color sample transmitted from the means, and a color space in the predetermined color system for receiving the received measurement values The correction formula deriving means for deriving a plurality of correction formulas for performing correction for approximating the measurement value to the stored reference value for each of the divided measurement values And for each of the divided measurement values, the measurement values are corrected by the plurality of derived correction expressions, and the plurality of derived correction expressions are based on the measurement values corrected by the plurality of correction expressions. Correction with the highest correction accuracy A management server having correction formula determination means for determining the correction formula registration means for registering the determined correction formula as a correction formula for correcting the difference for each of the divided measurement values. A color management system characterized by that.   The correction formula determination unit is configured to derive a calculation unit that calculates a color difference between the measured value corrected by the plurality of correction formulas and the stored reference value, and a correction formula that minimizes the calculated color difference. The color management system according to claim 1, further comprising: a correction formula selection unit that selects a plurality of correction formulas and uses the correction formula as the correction formula with the highest correction accuracy. The calculation means calculates the color difference between the measured value corrected by the plurality of correction formulas and the stored reference value as the L ^* value, a ^* value, and b in the CIE L ^* a ^* b ^* color system. ^* is the difference value [Delta] L ^* value, to calculate the .DELTA.a ^* values and [Delta] b ^* are color difference based on the value ^{ΔE = {(ΔL *) 2} + (Δa *) 2 + (Δb *) 2} 1/2 value At the same time, the correction formula selection means selects a correction formula that minimizes the maximum value or average value of the calculated ΔE value from the plurality of derived correction formulas, and selects the correction formula with the highest correction accuracy. 3. The color management system according to claim 2, wherein a high correction formula is used.   The correction formula registration unit converts the correction formula selected by the correction formula selection unit into the tristimulus values of X, Y, and Z in the XYZ color system by using the received measurement value and the stored reference value. The color management system according to claim 2, wherein the color management system is registered as a correction expression expressed as follows. The management server further includes a correction formula transmission unit that transmits the correction formula registered by the correction formula registration unit to a corresponding one of the plurality of terminal devices,
The plurality of terminal devices further include a correction formula receiving unit that receives the correction formula transmitted from the correction formula transmitting unit, and a correction formula display unit that displays the correction formula received by the correction formula receiving unit. The color management system according to claim 1, wherein the color management system is a color management system. In order to perform color management of a plurality of image output devices installed at each site, a reference value of measurement values of a plurality of colorimeters that measure the output matter arranged at each site and output from the image output device; A color management method for deriving a correction formula for correcting the difference based on the difference of
In a plurality of terminal devices arranged for each base,
A color sample measurement value transmission step of transmitting measurement values in a predetermined color system at a plurality of measurement points of the color sample measured by the colorimeter;
In a management server connected to the plurality of terminal devices via a network,
A color sample measurement value storing step for storing in advance a measurement value in a predetermined color system at a plurality of measurement points of the color sample measured by a reference colorimeter as the reference value, and transmitting the color sample measurement value A color sample measurement value receiving step for receiving measurement values in a predetermined color system at a plurality of measurement points of the color sample transmitted in step, and a color space in the predetermined color system for receiving the received measurement values A correction formula deriving step for deriving a plurality of correction formulas for performing correction for approximating the measured value to the stored reference value for each of the divided measurement values And for each of the divided measurement values, the measurement values are corrected by the plurality of derived correction expressions, and the plurality of derived correction expressions are based on the measurement values corrected by the plurality of correction expressions. The best from A correction formula determining step for determining a correction formula with high correction accuracy, and a correction formula registration step for registering the determined correction formula as a correction formula for correcting the difference for each of the divided measurement values. A color management method characterized by the above.   In the correction formula determination step, the calculation step for calculating a color difference between the measured value corrected by the plurality of correction formulas and the stored reference value, and the correction formula that minimizes the calculated color difference are derived. The color management method according to claim 6, further comprising: a correction formula selection step of selecting from among a plurality of correction formulas and using the correction formula as the correction formula with the highest correction accuracy. In the calculation step, as a color difference between the measured value corrected by the plurality of correction formulas and the stored reference value, the L ^* value, a ^* value, and b in the CIE L ^* a ^* b ^* color system ^* is the difference value [Delta] L ^* value, to calculate the .DELTA.a ^* values and [Delta] b ^* are color difference based on the value ^{ΔE = {(ΔL *) 2} + (Δa *) 2 + (Δb *) 2} 1/2 value At the same time, in the correction formula selection step, a correction formula that minimizes the maximum value or average value of the calculated ΔE value is selected from the plurality of derived correction formulas, and this is selected as the correction accuracy with the highest correction accuracy. 8. The color management method according to claim 7, wherein a high correction formula is used.   In the correction formula registration step, the correction formula selected in the correction formula selection step is converted from the received measurement value and the stored reference value to tristimulus values of X, Y, and Z in the XYZ color system. The color management method according to claim 7, wherein the color management method is registered as a correction expression expressed as follows. In the management server,
A correction formula transmission step of transmitting the correction formula registered in the correction formula registration step to a corresponding one of the plurality of terminal devices;
In the plurality of terminal devices,
The correction formula receiving step for receiving the correction formula transmitted from the correction formula transmitting step, and the correction formula display step for displaying the correction formula received in the correction formula receiving step, further comprising: The color management method according to any one of claims 6 to 9.

Images