JP4377802B2 - Toning method for colored articles - Google Patents

Description

The present invention relates to a method toning wearing colored article products, particularly, trials utilized to carry out the compounding decision namely toning colorants to be used in producing colored articles, such as colored resin molded article and painted how to perform a tone color of the colored articles using book are targeted.

In order to produce a colored article, it is applied with a paint blended and prepared in a desired color, or a colorant formulated and blended in a desired color is added to a molding material such as a resin for molding the colored article. . For example, in the manufacture of automobiles, the surface of the vehicle body is painted. When manufacturing the housing | casing of an electrical product, it shape | molds using the colored resin molding material to which the coloring agent adjusted to the desired color was added. There is also a technique for dyeing fabrics and yarns with dyes adjusted to a desired color.
The manufacturer or supplier of a colorant such as a paint can combine the target colors specified by the manufacturer of the colored product or the user of the colorant in combination with the target color. Manufacture and supply mixed colorants that can express A technique for obtaining such a combination of mixed colorants is called toning or color matching. In recent years, color expression of mixed colorants obtained by combining and combining multiple colorants is predicted based on various theoretical calculations, empirical data, statistical data, etc. A technique called computer color matching (CCM) has been widespread that can determine the composition of a mixed colorant that can express a target color without painting or molding a resin molded product.

In the CCM technology, a technique for displaying an expression color of a mixed colorant composed of a combination of a plurality of colorants as a color sample image or an electronic color sample on a color monitor connected to the computer, or a computer graphic created by computer graphic software There have been proposed techniques for designating a target color in an image (CG image) and obtaining information on a target color from image data of a CG image.
For example, in the technique described in Patent Document 1, numerical data of spectral reflectance necessary for the CCM technique is obtained from CG image data drawn based on the variable angle spectral reflectance distribution, and the display color of the CG image is obtained. A technique for estimating a paint formulation that results in a paint color corresponding to is shown.
Japanese Patent Laid-Open No. 10-227696

Even when the color article is toned based on the color sample based on the CG image, there is a problem that the color of the actually produced color article does not exactly match the color of the color sample displayed on the image.
One reason for this is that colored articles that are actually produced have fine irregularities on the surface or subtle differences in gloss. Even when the same paint or resin colorant is used, the color perceived when the colored article is viewed may differ considerably due to the microscopic surface shape difference as described above.
In the color sample based on the CG image, for example, a desired color is expressed by a combination of RGB signal strengths in each pixel of the display screen. In a certain area area expressing a color sample, the same color is expressed with the same combination of RGB signal intensities in all pixels. Similar to the printing surface of a color sample plate or a color sample book having a smooth surface, the whole is a uniform solid image. Even if a colorant that matches the target color is determined in the color sample of such a solid image, an actual colored article having a surface shape including the fine irregularities described above exhibits a color that is significantly different from the target color. It will be.

In the CG image technique, a technique for expressing fine irregularities on the surface of an object or arbitrarily changing the texture of the surface is also known. In this case, by changing the intensity of the RGB signal in a certain pattern for each pixel in a certain area of the object image, the color density and intensity are changed, and the surface texture such as fineness, unevenness and graininess Express. However, since the surface texture formed with such a CG image is created mathematically or virtually, there is inevitably a difference between the surface shape of the target article actually manufactured. The difference between the color of the color sample of the CG image and the color of the actual colored article could not be sufficiently eliminated.
It is an object of the present invention to be able to express a color closer to an actual colored article as a color sample consisting of a colored image created by CG technology, and to realize an accurate and quick toning work. It is.

That is, the toning method for a colored article according to the present invention is a method for toning a colorant for coloring a target article to a target color, and coloring is performed for each of a plurality of coloring agents used for toning. A step (m) of measuring a colorimetric sample colored with an agent and having a smooth surface to obtain color characteristic information including the spectral reflectance of the colorant, and the individual coloring obtained in the step (m) Applying the method (n) for obtaining color characteristic information of a mixed colorant when a plurality of colorants used for toning are combined and blended from the color characteristic information of the agent, and a method for creating a color sample for a colored article described below Then, a color sample image obtained from the shape characteristic information on the target article obtained in the step (b) and the color characteristic information of the mixed colorant obtained in the step (n) is displayed on the display screen of the image display device. And the color of the color sample image displayed in the step (o) Based on the evaluation in the step (p) for comparing and evaluating the target color and the evaluation in the step (p), the combination of a plurality of colorants in the step (n) is changed, and the steps (o) to ( a step (q) of repeating p), and a toning method for a colored article.
Here, the preparation method of the color sample for colored articles is as follows.
A method of creating a color sample for evaluating an expression color in a coloring state of a target article to be colored by a colorant, wherein the color sample is a color sample composed of a colored image displayed on an image display device, A step (a) of photographing at least a surface of a sample article having a surface shape in common with the target article under a plurality of conditions in which the relative positional relationship between the illumination direction and the photographing direction is different, and a plurality of conditions by the step (a). Step (b) for obtaining shape characteristic information including surface normal vector and spectral reflectance at each pixel by calculating information of the photographed image, and making a color sample made of the same material as the target article Step (c) for obtaining color characteristic information including a spectral reflectance of the colorant by measuring a colorimetric sample colored with a colorant and having a smooth surface, and shape characteristic information obtained in the step (b) And the step (c A color sample image composed of a colored image of a virtual object in which the surface having the shape characteristic information is colored and the surface having the shape characteristic information is colored. A method for producing a color sample for a colored article, comprising:
The color sample for colored articles used in the toning method of the present invention (hereinafter sometimes referred to as “color sample for colored articles according to the present invention” or “color sample for colored articles of the present invention”) is a colorant . A color sample for evaluating the expression color in the colored state of the target article to be colored by a color sample image displayed on an image display device, the color sample image being a shape related to the surface shape of the target article This is a colored image of a virtual object obtained by synthesizing characteristic information and color characteristic information of the colorant and having a surface having the shape characteristic information colored with the color characteristic information.
[Target article]
Any article that is industrially manufactured and colored is an object as long as it is an article that needs to evaluate the expression color in the colored state.

Examples of the material of the target article include synthetic resin, metal, ceramic material, fiber material, and natural material. When the raw material remains as it is, it may be in a form that can be used as an industrial product such as a processed or secondary processed material. Some composite articles are a combination of multiple materials or parts.
Specific examples include various mechanical products, electrical products, daily necessities, building materials, clothing items, clothing items, other industrial products, and parts and materials used for these industrial products.
Examples of coloring of the target article include those in which the surface is painted or coated, those in which a coloring material is used as the material of the target article itself, and those in which the target article is dyed. In any case, a coloring agent is used for coloring.

The target article, in a colored state, has a surface shape that is not smooth and has physical irregularities. Specifically, it may have a fine concavo-convex shape representing a texture pattern, a satin pattern, a hairline pattern, or the like. Also included are microscopic irregularities due to surface roughness and processing marks that occur during molding, processing, and surface treatment. The surface may be uneven depending on the material of the target article. Depending on painting, coating, film lamination, etc., the surface may be different from the material itself. The present invention is useful when the physical shape on the surface greatly affects the expression color of the colored state.
[Sample article]
The sample article used to acquire the shape characteristic information only needs to have the same surface shape as the target article to be actually produced.

The same surface shape means that the same expression color can be obtained when coloring with a colorant. It is only necessary that the fine unevenness shape and the light reflection characteristics, which are physical structures that determine the gloss, gloss, surface texture, and the like of the surface match. The macroscopic shape of the target article and the overall structure, function, and characteristics need not be the same.
Specifically, it may be the target article itself to be produced, may be a part of the product, or may be a prototype before production, or obtain shape characteristic information. Therefore, it may be a measurement sample prepared for the purpose. It is useful as a sample article if it is made of the same material as the target article under the same manufacturing conditions. When changing the design of the color of the production product, an old production product that has already been colored can be used.

[Colorant]
As the colorant, a normal colorant produced by combining pigments and dyes is used.
Usually, a colorant having a target color can be obtained by combining a plurality of basic colorants in an appropriate ratio. In addition to a general opaque colorant, the colorant includes a transparent transparent colorant, a glittering colorant that glitters in a pearl shape or a metallic shape, and the like.
The usage pattern of the colorant varies depending on the coloring method of the target article. For example, in the case of a colored resin molded product, a liquid or powder colorant is mixed with the resin molding material. A master batch containing a colorant at a high concentration may be used by mixing with a resin molding material. When coloring the surface of the target article by painting or coating, a paint or coating agent containing a colorant is used.

Therefore, the colorant may contain a film forming component or an additive for enabling the use of the colorant in addition to the color component intended for coloring itself.
[Color samples for colored articles]
The color sample for colored articles is a color sample for evaluating the expression color in the coloring state of the target article to be colored with the colorant. It consists of color sample images displayed on the image display device. A color sample such as a color sample plate is not physically produced, but is a color sample based on a virtual CG image displayed on the display screen of the image display device.
Therefore, the color sample for colored articles is composed of image information or electronic information necessary for displaying a color sample image, information consisting of a numerical value group, a numerical value group, and the like.

The shape and size of the color sample displayed on the image can be arbitrarily set. Usually, it is a two-dimensional image representing a substantially flat surface, but a three-dimensional image representing a state in which the surface or curved surface of an article having a three-dimensional shape is colored can also be used. It may be an animation image in which the viewpoint and lighting conditions change continuously. If it is an image expressing the shape and operation of the target article to be colored, the expression color of the colored state can be appropriately evaluated with a feeling close to the actual usage state.
[Shape characteristics information]
Of the information necessary for creating the color sample image of the target article, it is information relating to the shape characteristic excluding information relating to the color characteristic that varies depending on the colorant.

  The shape characteristic information includes at least physical elements and conditions that affect the expression color when the target article is colored, such as surface irregularities and surface textures, among the surface shape of the target article. Information on optical characteristics such as light reflection, diffusion, and refraction inherent to the material of the target article can also be included. Information on the overall or macro shape of the target article, for example, a shape that can be recognized clearly distinct from the expression color, such as whether it is a sphere, a cuboid, or whether the surface is flat or curved. It is not always necessary as shape characteristic information. However, when expressing up to the entire three-dimensional shape of the target article with a color sample image, information on the shape of the entire target article can also be included.

The shape characteristic information is obtained for each pixel by photographing the surface shape of the sample article corresponding to the target article and performing arithmetic processing on the obtained image information. By obtaining shape characteristic information for each pixel, which is the basic unit of image information when displaying a color sample image on the display screen of an image display device, the expression color of the color sample image can be accurately and accurately required. It can be displayed.
In order to obtain shape characteristic information, various surface shape measuring devices and surface shape measuring techniques can be used. Any known technical means can be adopted as long as it is a technical means capable of acquiring the surface shape of the sample article as described above as electronic information necessary for creating a CG image. Digital archive technology can be used to obtain shape property information. The digital archiving technology is a technology for the purpose of digitizing art information and crafts such as paintings or faithfully reproducing them as CG images.

As shape characteristic information for creating a color sample image, the surface normal vector and the spectral reflectance at each pixel of the image information of the sample article can be used. A reflection model created from the surface normal vector and spectral reflectance of each pixel can be used.
Techniques described in the following documents can be used as digital archive techniques that can be used to acquire shape characteristic information.
<Technical Reference 1>
Technical paper “Measurement and rendering of art paintings using color cameras”, Shoji Tominaga et al., IPSJ Transactions, Vol. 45, No. 1 reprint, 350-361, published in January 2004.

  Technical Document 1 discloses a technique for precisely computerizing even the difference in expression color due to fine unevenness on the surface of a painting. In the case of paintings where subtle surface irregularities due to overlapping of paints and handwriting are important elements in expression, such as oil paintings, it is possible to express more faithful images by converting such fine irregularities into information. Become. Specifically, when a picture is taken with a color digital camera, the illumination direction and the shooting direction are changed to a plurality of directions, and the surface normal vector at each pixel point is obtained from the image information for the plurality of shot images. Spectral reflectance and the like are calculated, and an image is displayed by a CG image rendering technique based on the surface normal vector and spectral reflectance data. As a result, faithful image expression including the above-described fine unevenness can be achieved. It is also possible to display an image when a picture is placed under arbitrary lighting conditions or an image from a viewpoint from a different direction.

Of the techniques disclosed in the technical document 1, a technique for faithfully acquiring the surface shape of a picture as electronic information can be adopted as the shape characteristic information and the acquisition technique in the present invention. The shape characteristic information obtained in this way includes information on the surface shape of the sample article with such fidelity that the aesthetic value of the painting can be expressed.
[Color characteristics information]
Of the information necessary for creating a color sample image, this is information relating to the color characteristics of the colorant used for coloring. The shape characteristic information of the target article, that is, the sample article is not included. In other words, it is not characteristic information associated with the target article, such as surface characteristics, shape, and material of the target article, but characteristic information associated with the colorant. By separating the shape characteristic information of the target article and the color characteristic information of the colorant, it is easy to obtain a color sample for a colored article that is colored with an arbitrary colorant for an arbitrary target article.

Basically, a technique common to a technique for acquiring color characteristic information performed in a normal color matching technique or color measurement technique is applied.
Color characteristic information can be obtained by measuring a colorimetric sample colored with a colorant and having a smooth surface.
By using a colorimetric sample having a smooth surface, it is possible to exclude information influenced by the surface shape of the colorimetric sample from the acquired color characteristic information.
Usually, coloring of a target article is rarely performed with only one type of colorant, and is performed using a mixed colorant obtained by blending a plurality of types of colorants having different colors and characteristics. In this case, the color measurement sample colored with the color mixing colorant may be measured, but separately for each of a plurality of types of colorants used for color mixing, a color measurement sample is prepared and color measurement is performed, The color characteristic information of the mixed colorant can be calculated from the color characteristic information of the obtained individual colorant. As a technique for obtaining the color characteristic information of the mixed colorant from the color characteristic information of the individual colorant, a technique known from a general toning technique or CCM technique is applied.

As color characteristic information, spectral reflectance obtained by the color measurement is used. The spectral reflectance is measured and calculated in accordance with a normal colorimetric apparatus and colorimetric data processing procedures.
[Color sample image]
It is the coloring image of the virtual thing by which the color which has color characteristic information was given to the surface which has shape characteristic information. It is obtained by synthesizing the shape characteristic information acquired from the sample article and the color characteristic information acquired from the colorant.
If the color sample image accurately represents the expression color of the target color sample for a colored article, its shape and size can be arbitrarily set. The shape may be the same as the target article, or may have a shape different from the target article. Usually, it is a rectangular shape or other simple figure shape, but it may be a planar shape or a three-dimensional shape indicating the overall shape of the target article. In the case of a three-dimensional shape, it is possible to add a shadow, an inclination, and a perspective expression to a three-dimensional object using a CG image creation technique. In this case, a difference in expression color is added depending on the portion of the three-dimensional object.

[Method for creating color sample for colored article]
A color sample for evaluating an expression color in a coloring state of a target article to be colored by a colorant, which is a method of creating a color sample image displayed on an image display device.
A method including the following steps can be employed by using the digital archive technique disclosed in the above-mentioned technical document 1.
Step (a): The surface shape of the sample article is photographed under a plurality of conditions in which the relative positional relationship between the illumination direction and the photographing direction is different.
Specifically, the sample article is fixed, a photographing camera is installed at a position where the surface shape of the sample article can be photographed, and a light source such as an illumination lamp is arranged at different positions with a certain angle around the sample article. In this state, the illumination light may be applied to the sample article. Each time the light source position is changed, the surface shape of the sample article is photographed with a camera.

The wavelength component of the illumination light is not particularly limited as long as the light source can irradiate illumination light used for normal image capturing. A standard illumination lamp can be used.
A normal digital camera can be used as long as the camera can capture a minute surface shape of the sample article and output electronic image information. A general RGB color digital camera can be used.
The number of times of changing the illumination direction and the setting of the illumination direction for the sample article may be set to such an extent that the details of the fine three-dimensional shape in the surface shape of the sample article can be acquired as image information.
Step (b): Information on the image captured under a plurality of conditions in the previous step (a) is calculated to obtain shape characteristic information including a surface normal vector and spectral reflectance at each pixel.

The technique shown in the above-mentioned Technical Document 1 can be applied to the calculation method and calculation formula of the surface normal vector and the spectral reflectance.
If the shooting camera and computer software programmed with an arithmetic processing method are connected by an information transmission line, the captured image is immediately processed and processed as shape characteristic information in a computer storage device or an external recording device. Can be stored. A database for storing shape characteristic information can also be configured.
Step (c): Color characteristics information including the spectral reflectance of the colorant is measured by measuring a colorimetric sample made of the same material as the target article, colored with a colorant that creates a color sample, and having a smooth surface. Ask.

Basically, ordinary colorimetric techniques are applied. If the colorimetric sample is made of the same material as the target article, color characteristic information including optical characteristics of the material can be obtained. However, even a colorimetric sample made of a material different from that of the target article can be regarded as substantially the same material as the target article if there is no significant difference in basic color characteristics. It is also possible to obtain color characteristic information of a colorimetric sample made of substantially the same material as the target article by performing a correction calculation on the difference in optical characteristics between the material of the colorimetric sample and the material of the target article.
Step (d): The shape characteristic information obtained in the step (b) and the color characteristic information obtained in the step (c) are combined, and the color characteristic information is applied to the surface having the shape characteristic information. A color sample image composed of a colored image of a virtual object that has been colored is displayed on the display screen of the image display device.

Basically, ordinary CG image creation technology and image display technology can be applied. Rendering technology, ray tracing technology, etc. used for CG image creation are used.
The color sample image displayed on the display screen may be a two-dimensional planar image or a three-dimensional stereoscopic image. It can also be a continuous image, that is, an animation image, which changes depending on a difference in illumination direction or a difference in viewpoint direction.
[Toning method of colored articles]
This is a method for toning a colorant for coloring a target article with a target color.
Basically, a normal toning technique or CCM technique is applied. In a normal CCM technique, a color sample image created with image information including the shape characteristic information of the target article is used as a color sample image to be displayed.

Specifically, a method including the following steps is adopted.
Step (m): For each of a plurality of colorants used for toning, the colorimetric sample colored with the colorant and having a smooth surface is measured to obtain color characteristic information including the spectral reflectance of the colorant. deep.
Basically, normal color sample creation technology and colorimetry technology are applied. If the color characteristic information including the spectral reflectance is stored in the colorant database as electronic information, it is only necessary to extract the color characteristic information as necessary. If the information of the existing colorant database is used, it is not necessary to perform this step (m) for each toning operation.
Step (n): From the color characteristic information of the individual colorant obtained in the previous step (m), the color characteristic information of the mixed colorant is obtained when a plurality of colorants used for toning are combined.

A technique common to a normal CCM technique is applied. The color characteristic information of the mixed colorant can be obtained by reading the color characteristic information and the blending ratio of the individual colorant into CCM software running on a computer and performing a predetermined calculation process. If there is the above-mentioned colorant database, the color characteristic information of any color mixing colorant can be created by arbitrarily combining the color characteristic information of the colorant extracted from the colorant database.
In normal CCM software, the operator displays the color sample of the individual colorant or mixed colorant on the display screen of the image display device, and inputs the selection of individual colorant, blending ratio, etc. The expression color of the colorant can be displayed on the image. However, if the shape characteristic information of the target article is not taken into account, the accurate expression color when the target article is colored is different.

Therefore, the normal CCM technique can be used until the stage of obtaining the color characteristic information of the mixed colorant, but the process (o) described below is applied to the stage of creating and displaying the image information.
Step (o): Applying the color sample preparation method for colored articles described above, the shape characteristic information of the sample article obtained in step (b) in the color sample preparation method for colored articles, and the previous step (n) A color sample image composed of a colored image of a virtual object obtained from the color characteristic information of the obtained mixed colorant is displayed on the display screen of the image display device.
By synthesizing the shape characteristic information acquired from the sample article and the color characteristic information of the mixed colorant, a color sample image that accurately represents the expression color of the target article when actually colored with the colorant is obtained.

The color sample image may be a two-dimensional image or a three-dimensional image imitating the three-dimensional shape of the target article.
Step (p): The color of the color sample image displayed in the previous step (o) is compared with the target color and evaluated.
If it is evaluated that the color of the color sample image displayed on the screen matches the target color or falls within the error range, the toning operation is finished.
If there is an unacceptable difference between the color of the color sample image and the target color, the next step (q) is performed.
Step (q): Based on the evaluation in the previous step (p), the combination of a plurality of colorants in the step (n) is changed, and the steps (o) to (p) are repeated.

Usually, it is rare to obtain a blended colorant that can express the target color in one toning operation, that is, from the step (n) to the step (p), and by repeating the toning operation multiple times. As a result, the mixture of the mixed colorants is gradually brought closer to the final combination that can express the target color.
When a color sample image that expresses the target color is finally obtained, the toning operation ends.
Data such as the type and blending ratio of the color mixing colorant used to create the color sample image is stored, and when the actual target article is produced, the color mixing colorant having the stored blending is used.
As described above, since the color sample image is created including the shape characteristic information of the target article, the expression color of the actually produced target article is close to the target color so that almost no difference is recognized. Often.

However, in the step (p), it is evaluated that the color of the color sample image matches the target color, and even if the target article is produced using the mixed colorant produced by the blending, the expression color of the target article is It may be slightly different for the target color. This problem is caused by the fact that the manufacturing conditions when producing the target article using the mixed colorant do not exactly match the manufacturing conditions of the sample article from which the shape characteristic information is obtained. May occur due to errors and variations in obtaining the color, errors in creating a CG image of a colored image, and the like.
In such a case, the toning operation can be performed once again after obtaining the shape characteristic information from the actually produced target article. It is also possible to cope with the acquisition of the shape characteristic information under more accurate conditions. This can be dealt with by improving the accuracy of CG image creation. Further, when the steps (n) to (p) are repeated once again without changing the shape characteristic information, fine adjustment is performed so that a slight difference remains between the color of the color sample image and the target color. You can also respond. What direction should be fine-tuned may be determined based on the difference between the expression color of the produced target article and the target color.

In the color matching method described above, the colorant supplier or the target article manufacturer can perform all operations, and the colorant supplier and the target article manufacturer exchange information. Toning work can also be carried out in cooperation.
For example, step (m) to step (n) are usually performed by a colorant supplier having the ability and equipment to perform these operations. Production of the sample article may be easier to manufacture under conditions that are consistent with the target article that is actually produced, if it is performed by the manufacturer of the target article. If the design information of the target article is provided, the supplier of the colorant can also produce the sample article and acquire the shape characteristic information.

If the manufacturer of the target article performs the display of the color sample image and the evaluation of the step (p) in the step (o), the color sense and the target color tolerance between the manufacturer of the target article and the colorant supplier Problems such as differences in degrees can be solved. If both the supplier of the colorant and the manufacturer of the target article have an image display device that displays the color sample image of step (o), the manufacturer of the target article while viewing substantially the same color sample image. And accurate communication with the colorant supplier.
If the colorant database for each individual colorant is provided to the manufacturer of the target article, the manufacturer of the target article can perform the process from determining the colorant mixture in step (n) to evaluating the step (p). It can also be done.

A color sample for a colored article according to the present invention is a virtual object displayed on an image display device by combining shape characteristic information on the surface shape of a target article to be colored and color characteristic information of a colorant used for coloring. It is a color sample image which consists of a coloring image. The color sample image can accurately represent the difference in expression color due to the shape characteristics such as fine irregularities on the surface of the target article by the difference in display information such as RGB values in individual pixels. It is possible to provide a color sample for a colored article having an accurate color tone and color feeling that reflects even a fine surface texture difference of the target article.
If the target article changes, only the shape characteristic information can be recreated, and if the target color or usable colorant changes, only the color characteristic information needs to be recreated. An article color sample can be provided easily and quickly.

As the shape characteristic information, the surface of a sample article having the same surface shape as that of the target article is photographed, and the obtained image information is processed and processed using the surface normal vector and spectral reflectance obtained for each pixel. If the spectral reflectance of the colorant obtained by measuring a colorimetric sample colored with a colorant and having a smooth surface is used, shape characteristic information and color characteristic information can be easily obtained, and color sample images can be created. Can be done easily and accurately.
If the shape characteristic information is obtained by photographing the surface shape of the sample article under a plurality of conditions in which the relative positional relationship between the illumination direction and the photographing direction is different, and calculating the obtained image information, it is special. Therefore, it is possible to obtain shape characteristic information economically and efficiently by using a general-purpose digital camera or lighting device without preparing a large measuring device.

In order to create and display a color sample image from the shape characteristic information and the color characteristic information, a general-purpose CG image creation technique and an image display device can be used, so that work is easy and economical.
By using such a color sample for colored articles or a technique for producing the same, toning of the colorant for coloring the target article in a target color is performed extremely efficiently, economically, and with high accuracy. be able to. When a target article is produced using a toned colorant, which has been a problem with conventional toning techniques, the problem that the target color cannot be expressed sufficiently is solved. The troublesome work of repeating the color toning, blending and manufacturing, trial manufacture of the colored article and evaluation of the expression color is no longer necessary. In particular, using a computer, an image display device, and a communication means, a colorant supplier that colors, mixes and supplies the colorant, and a target article that produces the target article using the supplied colorant The manufacturer can efficiently perform the color matching work with high accuracy while exchanging information with each other.

  As a result, high-quality products can be produced economically and efficiently at the production site of various colored articles.

According to the basic process shown in FIG. 1, a color sample for colored articles is obtained.
[Sample article]
It is used to obtain shape characteristic information for creating a color sample for a colored article.
As shown in FIG. 1, a resin molded product having a simple rectangular plate shape is used as the sample article 10. The resin molded product may have the color of the resin molding material itself. If a colorant is blended in the resin molding material, the resin molded product is in a colored state. The coloring at this stage does not have to be the same coloring as the final article to be manufactured.
The surface of the sample article 10 is almost flat, but is not a smooth surface like a normal color sample plate. It has the same surface shape as when the target article for which the expression color in the colored state is to be evaluated by the color sample is actually produced and used. It is manufactured under the same manufacturing conditions using the same material as the target article, and can be regarded as the same as the target article in terms of surface shape. However, the overall shape and structure excluding the surface shape is different from the target article.

Specifically, for example, a target article made of a resin molded product may have fine irregularities due to differences in the characteristics of the resin molding material and molding conditions of the resin molding. In some cases, a concavo-convex pattern is positively formed by satin finish or embossing. Such a surface shape of the target article also has the surface of the sample article 10.
[Shape characteristics information of sample article]
This is obtained from the result of actual measurement of the sample article 10. This is information indicating the influence of a difference in surface shape of the target article on the color expressed on the surface of the colored target article when the colored target article is produced.

The shape characteristic information is obtained for each minute region obtained by finely dividing the surface of the sample article 10 corresponding to each pixel that is a basic unit of image display in the colored image of the color sample for the colored article displayed on the image display device. Desired. One sample article 10 is obtained not as a piece of shape characteristic information but as a set of a large number of pieces of shape characteristic information different for each pixel.
Specific examples of the shape characteristic information include a surface normal vector obtained for each pixel constituting the captured image of the sample article 10, a spectral reflectance, and a reflection model obtained by combining them. In order to measure and calculate the shape characteristic information, the technique described in the above-mentioned technical document 1 can be applied. Detailed explanation will be given in another section described later.

[Color swatches for individual colorants]
In order to obtain color characteristic information for each of a plurality of colorants used for coloring, the color sample plate 20 produced for each colorant is used.
The colorant for obtaining color characteristic information may be a colorant composed of only a single colorant or a premixed colorant produced by blending a plurality of colorants. When the colored article is manufactured, it may be a basic unit colorant that is handled as one colorant and whose blending amount is determined.
The color sample plate 20 is manufactured by a technique common to a normal color sample plate. For example, it can be obtained by molding a resin molding material colored with a corresponding colorant. The sample article 10 can be molded from the same resin molding material as that for manufacturing the sample article 10. However, the surface of the color sample plate 20 is a uniform smooth surface with no unevenness. The color sample plate 20 having a smooth surface can be obtained by using a mold having a smooth surface without unevenness or a mirror-finished mold as a mold for resin molding. Unevenness can be eliminated by polishing the surface of the resin molded product.

As shown in FIG. 1, the color sample board 20 is produced for every colorant used for manufacture of a colored article, and obtains individual color characteristic information for each colorant.
[Color characteristics information of individual colorants]
The color characteristic information is obtained for each of the color sample plates 20 of a plurality of colors by applying a color measurement technique of a normal color sample plate.
The color characteristic information includes one numerical value or a numerical value group representing the spectral reflectance, or a set of spectral reflectances under different conditions, a coefficient group for calculating the spectral reflectance, and the like. Spectral reflectance can be measured with a measuring device such as a normal spectrophotometer. Spectral reflectance can be calculated by substituting measurement data into various known spectral reflectance calculation formulas. Depending on the calculation formula for calculating the spectral reflectance, the measurement conditions and measurement items of the color sample plate 20 may differ.

As shown in FIG. 1, color characteristic information (1), (2), (3)... Is obtained for each of a plurality of colorants.
It is not necessary to prepare the color sample plate 20 and obtain color characteristic information every time a colored article or a colored article color sample is produced. For each colorant that can be used, the color sample plate 20 can be prepared in advance, and the color characteristic information can be obtained and stored in a database. When creating an image of a colored article color sample, color characteristic information of a colorant used for the colored article may be extracted from a database storing color characteristic information for each colorant and used.
As such color characteristic information for each colorant, information common to color characteristic information used in a color sample creation technique and toning technique using an image using a normal computer can be used. Color characteristic information for each colorant that has already been obtained by a known color sample creation technique or toning technique can be used. In this way, it is possible to omit newly producing the color sample plate 20 and performing spectral colorimetry.

[Color characteristics information of mixed colors]
If the target color sample for a colored article is a color sample of a colored article colored with a single colorant, the single color color characteristic information of the color sample 20 produced using the colorant is used as it is. it can. Usually, a plurality of colorants are mixed in an appropriate formulation to produce a desired color mixture, and the target article is colored. In this case, it is necessary to obtain color characteristic information of the color mixture corresponding to the color mixture colorant in which a plurality of colorants are mixed at a specific mixing ratio.
The color characteristic information of the mixed colorant can be calculated based on the color characteristic information and the blending ratio of the individual colorant constituting the mixed colorant. Specifically, by applying a normal color sample creation technique, it is possible to obtain color characteristic information of a mixed color in which an arbitrary colorant is combined in an arbitrary composition. Color characteristic information of mixed colors is also obtained as numerical data of spectral reflectance.

FIG. 1 shows an image of a surface having mixed color characteristic information, that is, a mixed color image 22. In the conventional computer toning technique, such a mixed color image 22 is displayed on the display screen of the image display device, and the color of the mixed color image 22 is evaluated to perform the toning.
[Color sample image of the target article]
It is the image 30 corresponding to a color sample when the target article is colored by combining any colorant with any formulation. Instead of producing a color sample that physically colors the sample article 10, a colored image of the virtual article, that is, a color sample image is displayed on the display screen of the image display device.
The display screen of the image display device basically develops the color of each pixel by a combination of electrical signals such as output intensity values corresponding to the basic three colors R, G, and B. Therefore, the color sample image 30 can be displayed by determining the RGB value of each pixel constituting the display screen.

If the combination combination of the colorants is determined, the color characteristic information of the above-mentioned mixed colors is obtained.
By combining the obtained color characteristic information of the mixed color and the shape characteristic information of the sample article 10 described above, a virtual CG image having a surface shape and an expression color in a state where the sample article 10 is colored is created, An RGB output signal in each pixel of the CG image is output to the image display device, and the color sample image 30 is displayed on the display screen of the image display device.
Since the color characteristic information is a constant value that does not change depending on the difference in pixel position, information that determines the RGB value of each pixel by performing an operation that adds common color characteristic information to the shape characteristic information of each pixel. Is calculated.

The difference between the color sample image 30 and the color mixture image 22 is that the color mixture image 22 does not incorporate shape characteristic information, so that the entire surface is a uniform solid image. In FIG. 30, even a fine uneven shape on the surface of the sample article 10 is expressed.
In order to create the image information of the color sample image 30 by combining the shape characteristic information and the color characteristic information, a rendering technique similar to that for a normal CG image can be applied. Specifically, the ray tracing method can be adopted. At this time, conditions such as the illumination direction, illumination light characteristics, and viewpoint direction with respect to the display image are specified, and the information is incorporated into the creation of the CG image. Detailed procedures for image creation will be described later.

If the information of the created CG image is sent to the image display device as a signal indicating the RGB value of each pixel, the sample article 10 having the same surface shape as the target article is displayed on the display screen. A color sample image 30 showing a state colored with a mixed color is displayed.
If the composition of the color mixture colorant is changed, the color sample information 30 of the new color mixture colorant can be displayed on the display screen in the same manner after recalculating the color characteristic information of the color mixture. In this case, the same data is used for the shape characteristic information. If the illumination condition is changed, image information in a state where the illumination condition is changed is created, and the color sample image 30 on the display screen is rewritten. Even if the shape characteristic information and the color characteristic ordinary method are the same, the expression color of the color sample image 30 changes if the illumination condition is changed.

In the image display device, for example, a color shift may occur between input image information and a displayed image due to characteristics of a liquid crystal panel for image display or a CRT tube. The occurrence of the deviation and the amount of deviation may vary depending on the color wavelength. Therefore, as the image display apparatus, an apparatus capable of displaying the input image information as an image as faithfully as possible is preferable. It is also desirable to have a color correction function that can correct or correct the image information to correct color. For example, an image display device having a gamma correction function is preferable. A high-precision monitor device for a computer used for general CG image creation can be used.
[Display screen]
FIG. 2 illustrates a display screen 40 when a color sample image of the sample article 10 is displayed on a monitor screen of a general computer. For example, it corresponds to one window screen on the display screen of a personal computer.

The display screen 40 has a rectangular window shape, and instruction buttons such as “end” and “cancel” are displayed on the window frame portion.
In the center of the display screen 40, an area 42 entitled “toning result” having a vertically long rectangular shape is provided. The color sample image 30 is displayed in the rectangular area 42.
A recipe 44 is displayed on the side of the color sample image 30. In the blending table 44, the code “Code” of the colorant used to create the color sample image 30, the name “colorant name”, the blending ratio “coloring ratio” of the colorant, and a colored article having a certain size are manufactured. The amount of each colorant required, such as “mixing amount”, is displayed. These data and calculated values are read out from the database storing the information for each colorant described above, or values obtained by calculation processing by a computer are displayed.

The computer operator can rewrite some of the item columns of the recipe table 44. Based on the rewritten data, recalculation processing is performed, and the color sample image 30 is automatically rewritten. For example, when the numerical values of the blending ratios are rewritten for some colorants, the blending ratios of the remaining colorants are recalculated and displayed again, or the color sample image 30 is recalculated with the rewritten blending ratios. Change to the color that was made. Similarly, when the color material name is rewritten to another colorant, the color characteristic information of the rewritten colorant is read from the database, color mixture color characteristic information is regenerated, and the color of the color sample image 30 is changed.
On the right side of the color sample image 30, a “sample name” for naming the information of the created color sample image 30, a lighting condition 48, and article information 46 are also displayed.

  In the illumination condition 48, information on the illumination condition used when creating the color sample image 30 is displayed. As a display of such illumination conditions, a general color value consisting of L *, a *, and b * and the type of illumination light “A” are displayed. The data of the illumination condition 48 can also be rewritten and input, and if the type of illumination light is changed, the color value changes correspondingly, and the color sample image 30 is recalculated based on the illumination condition data. And reappears. If you store several standard standard light source names and color value data used for colorimetry and toning as an illumination light database, you can rewrite the lighting condition 48 data by simply rewriting the type name. Then, a color sample image 30 based thereon is created.

  In the article information 46, data related to the sample article 10 and the target article that is the basis of the sample article 10 is displayed. For example, “article data” indicating the type and number of the sample article 10, “resin amount” indicating the amount of resin molding material necessary for using the sample article 10, and “colorant” indicating the total amount of colorant used ”Column. Each column of the article information 46 can be rewritten and input. For example, it is possible to display how the color sample image 42 changes when the sample article 10 is changed to one made of another resin material or one having a different surface finish with a combination of colorants having the same composition. . If the sample article 10 changes, the shape characteristic information created corresponding to the sample article 10 is replaced, recalculation processing is performed, and the color sample image 30 is rewritten.

A name can be given to a specific color sample image 30 created by determining the combination of the sample article 10 and the colorant, and related data can be stored or recorded in a storage device or an external recording device of a computer. The recorded data can be called to rewrite the color sample image 42 having different conditions and related information. If each data including the color sample image 30 is printed by a color printing device connected to a computer, the color sample image 30 can be carried as paper data. However, the reproducibility of the color sample image 30 on the printing surface differs depending on the performance of the printing apparatus, particularly the color reproduction capability.
By using the correction function incorporated in the basic software of the computer or the image control software, the color of the display screen 40 can be adjusted to set the expression color of the color sample image 30 more accurately.

[Acquisition of shape characteristic information]
FIG. 3 shows a method for acquiring the shape characteristic information of the sample article 10 using the technique described in Non-Patent Document 1 described above.
As shown in FIG. 3A, the sample article 10 is photographed by the camera 50 in a state where the illumination light having the illumination lamp 52 as a light source is applied to the sample article 10. The camera 50 includes an electronic image sensor that converts a captured image into electronic information of each pixel and acquires it. Basically, an ordinary color digital camera can be used. For example, a normal RGB digital camera can be used. By attaching a color filter to the illumination lamp 52 or the camera 50, it is possible to take an image that is decomposed for each wavelength component.

  In the imaging by the camera 50, the camera 50 is fixed to the front position of the sample article 10, and the illumination direction by the illumination lamp 52 is changed to a plurality of directions, and images in the respective illumination directions are taken. Further, in FIG. 3B, with the position of the illumination lamp 52 (not shown) being fixed, the shooting direction of the camera 50 is changed to a plurality of directions, and images from the respective shooting directions are acquired. For example, the imaging direction is the sum of the front of the sample article 10, directly above (0 degrees), 45 degrees to the right, 90 degrees to the right, 135 degrees to the right, 180 degrees directly below, 225 degrees to the left, 270 degrees to the left, and 315 degrees to the left. Images can be taken from 9 directions. The illumination direction can also be changed to the same nine directions for photographing.

Shape characteristic information is obtained based on a plurality of images obtained by changing the illumination direction and the shooting direction. The more image information with different illumination directions and shooting directions is combined, the higher the possibility of obtaining accurate shape characteristic information. If the illumination direction and the photographing direction are changed in the above nine directions, sufficiently accurate shape characteristic information can be obtained practically. When the accuracy is not so required, the types of illumination direction and photographing direction can be reduced.
[Calculation of shape characteristic information]
Image information of the sample article 10 photographed by the camera 50 is obtained as numerical data of an output signal at each pixel of the image sensor. For one pixel, the output value data sets are obtained by the number of different illumination directions. Specifically, the G sensor output value (radiance value) and the RGB sensor output value for each pixel can be obtained.

<Surface normal vector>
From the obtained data, a surface normal vector q at each pixel is obtained. In order to obtain the surface normal vector q, a known illuminance difference stereo method can be applied.
FIG. 4 shows a geometric model of the surface normal vector q.
As shown in FIG. 4 (a), the surface of the sample article 10 is illuminated by an illumination lamp, that is, a light source 52, and the surface of the sample article 10 is photographed by the camera 50. At a specific position of the sample article 10, illumination light from the light source 52 is indicated by an illumination vector I, and a light beam reflected by the surface of the sample article 10 and photographed by the camera 50 is indicated by a line-of-sight vector v. The vertical direction with respect to the surface is indicated by a vertical vector n. The surface normal vector q is obtained from the relationship between the illumination vector I and the line-of-sight vector v, and the direction can be expressed by an angle with respect to the vertical vector n. If the surface normal vector q is known, when light from an arbitrary direction hits the surface of the sample article 10, how the light is reflected on the surface, in other words, how it looks Can do.

As shown in FIG. 4B, if it is considered that the surface of the sample article 10 is composed of a collection of minute inclined surfaces, the surface normal vector q is a normal line orthogonal to the minute inclined surfaces. The vector extends in the direction, and the direction can be specified by an angle with respect to the vertical vector n. However, FIG. 4B shows a modeled state in order to make the explanation easy to understand, and it means that the actual surface of the sample article 10 is composed of such a minute inclined surface. Not to do.
In actual measurement, at each pixel of the image captured by the camera 50, the relationship between the illumination vector I and the line-of-sight vector v is determined based on the G sensor output value (radiance value) at least in three different illumination directions. By obtaining as data, the surface normal vector q in the three-dimensional space is calculated. As a specific formula for calculating the surface normal vector q, the above-described technical document 1 or the method for calculating the surface normal vector by the illuminance difference stereo method is applied.

In order to obtain the surface normal vector q, a minute inclined surface as shown in FIG. 4B is used by using a measuring device such as a three-dimensional laser microscope that can accurately measure the actual surface shape of the sample article 10. It is also possible to determine the surface normal vector q at. However, the method using the illumination lamp 52 and the camera 50 can perform measurement more easily and quickly, and can achieve practically sufficient measurement accuracy.
<Spectral reflectance>
Among the measurement data described above, the spectral reflectance information on the surface of the sample article 10 is also obtained from the RGB sensor output value at each pixel. The spectral reflectance may be calculated using a normal calculation formula or calculation procedure. If the surface normal vector and the spectral reflectance are known in each pixel, a CG image showing the surface shape or light reflection characteristics that gives such a surface normal vector and the spectral reflectance can be created.

<Reflection model>
A reflection model relating to the surface of the sample article 10 can be determined from the surface normal vector and the spectral reflectance. It can be said that the reflection model mathematically expresses the shape characteristic information of the sample article 10 by numerical values, mathematical expressions, coefficients of mathematical expressions, and the like.
In addition to the surface normal vector and the spectral reflectance, the reflection model can also include information such as spectral data of illumination light, which is an illumination condition at the time of measurement, and reflection parameters specific to the substance constituting the sample article 10.
If information related to the reflection model of the sample article 10 is stored in a database or the like, it can be taken out as necessary and used for creating a color sample image of the colored article or toning work.

[Create color sample image]
A procedure for creating the color sample image 30 by the ray tracing method described above will be described.
A ray casting method already known as an image forming technique is applied.
A square polygon corresponding to the color sample image 30 is set on the virtual three-dimensional space. The surface normal vector and spectral reflectance data obtained from the measurement of the sample article 10 are set at each coordinate point on the polygon. Further, color characteristic information consisting of spectral reflectance data of the mixed colorant to be colored is also set at each coordinate point. The shape characteristic information is different data at each coordinate point, but the color characteristic information is common to all coordinate points. Data on lighting conditions and viewpoints are also taken in as necessary.

Based on these data, the brightness of each coordinate point is calculated by the ray tracing method. In the ray tracing method, the luminance of each coordinate point can be calculated by determining the viewpoint position and the illumination condition, and substituting the reflection parameter into a known Torrance-Sparrow model. When the luminance of each coordinate point is obtained for the entire color sample image 30 and a CG image is created from the obtained data, image information of the color sample image 30 is formed.
If the image information of the created color sample image 30 is output to the image display device, the color sample image 30 is displayed on the display screen 40. At this time, the spectral reflectance data obtained from the color characteristic information of the above-mentioned mixed colorant is converted into tristimulus values X, Y, and Z, further converted into RGB input signals, and corrected by a gamma correction method. Then, the corrected RGB signal is output to the image display device to display the color sample image 30.

[Toning method of colored articles]
The color sample image creation technique described above can be applied to a computer color matching technique to perform toning work on a colored article.
The toning operation of the colored article is an operation of determining a combination of coloring agents necessary for coloring the target article to the target color when the target article and the target color to be colored are determined.
Usually, the manufacturer of the target product that produces the colored target product and the colorant supplier that manufactures and supplies the colorant prepared in a predetermined combination are different companies, business units, or manufacturing units. . In addition, the designer of the target article, the design designer, and the manufacturer that actually produces the target article may be different.

In view of this, the color sample image can be used to efficiently and accurately exchange information between the colorant supplier and the target article manufacturer, thereby proceeding with the toning operation.
Each of the colorant supplier and the target article manufacturer prepares a computer and an image display device so that information can be transmitted between each other through a communication line or the like. In each computer, image display software, image information processing software, communication software, and the like for displaying the display screen 40 as shown in FIG. 2 can be operated. On the colorant supplier side, a database including color characteristic information relating to a colorant that can be used for toning, information necessary for performing a color mixing operation, and the like is provided. For those other than the colorant supplier, only the minimum necessary information such as the sample image 30 and the sample name in the display screen 40 may be displayed.

The shape characteristic information of the sample article 10 is obtained in advance by either the colorant supplier or the target article manufacturer. The target article manufacturer can provide the colorant supplier with the design information of the sample article 10, that is, the target article, and the colorant supplier can produce the sample article 10 and obtain the shape characteristic information thereof.
<Presentation of target colors and modification of formulation>
The target article manufacturer or the like presents the target color to the colorant supplier. At this stage, a color sample closest to the target color selected from a normal printed color sample book is presented, a past manufacturing example close to the target color is presented, or image creation software is displayed on the computer display screen. A colored image of the created target article can be presented. However, since the image creation software does not measure the actual surface shape of the target article, the surface condition of the image is based on mathematically generated simple pattern shapes, virtual uneven shapes, surface textures, etc. The exact color is not necessarily expressed.

The colorant supplier who is presented with the target color selects a combination of colorants that appears to be suitable for coloring the target article to the target color. The combination of the colorants can be quickly determined by making use of the data of the toning work performed by the colorant supplier in the past, the experience and ability of the experienced person and the expert of the toning work.
The determined combination of the colorants is input to the computer, and the color sample image 30 representing the state in which the target article is colored is displayed on the display screen 40. If the difference between the target color presented by the target article manufacturer and the color of the color sample image 30 is large, the colorant combination is readjusted. What is necessary is just to determine the color sample image 30 which can be judged to match with the target color at the stage of the colorant supplier.

Information of the color sample image 30 determined by the colorant supplier is transmitted to a computer such as a target article manufacturer via a communication line or the like, and the sample image 30 is displayed on the display screen 40. If the target article manufacturer or the like determines that the color sample image 30 matches the target color, the color matching operation is completed by informing the colorant supplier to that effect. The colorant supplier supplies the target material manufacturer with a colorant that is toned with a combination formulation corresponding to the color sample image 30 or a coloring material such as a resin or paint containing the colorant.
Usually, the color sample image 30 presented first is often slightly different from the target color considered by the target article manufacturer. In this case, the target article manufacturer informs the colorant supplier of the difference from the target color. Differences in color values may be expressed numerically, or simply expressed in a sensory way, such as “a little more red” or “a little more bright”.

Based on an instruction from the target article manufacturer, the colorant supplier finely adjusts the colorant composition displayed in the composition table of the display screen 40. At this time, which colorant should be reduced or increased, which colorant should be newly added, etc. are determined quickly and accurately based on the experience and knowledge of the colorant supplier. Fine adjustments can be made. Needless to say, the colorant composition may be adjusted while checking the color sample image 30 on the display screen 40.
The color sample image 30 created with the adjusted colorant formulation is also displayed on the image display device of the target article manufacturer. If the color sample image 30 after adjustment is still different from the target color, the instruction to the colorant supplier, the blending adjustment of the colorant supplier, and the display of the new color sample image 30 are repeated.

If such a work is performed and the final colorant combination agreed between the target article manufacturer and the colorant supplier is determined, the color matching work is completed. The blended colorant is delivered from the colorant supplier to the target product manufacturer, and the target product manufacturer produces the target product. In some cases, the colorant supplier manufactures a colored molding material or a colored paint for manufacturing the target article and delivers it to the target article manufacturer.
If the color confirmation by the color sample image 30 is completed, when the target article is produced, the surface shape of the target article is caused by the color of the target article to be visually different from the target color. There is no big difference in color.

  Of course, the target article manufacturer manufactures the target article on a trial basis using the blended colorant delivered from the colorant supplier, and the color of the manufactured target article includes the designer and the designer. As a result of confirmation by related parties, it may be necessary to further adjust the color. Even in such a case, the target article manufacturer communicates the difference between the color sample image 30 and the product to the colorant supplier, so that the colorant recombination operation in the colorant supplier can be performed quickly and accurately. Yes. Further, if the difference between the color sample image 30 and the color of the manufactured article is incorporated as correction data into the arithmetic processing of the toning software, the subsequent toning work can be performed with higher accuracy.

  The color sample for colored articles according to the present invention is an accurate and efficient method for determining the blending of colorants used for producing a colored article, that is, toning, when producing a colored article comprising, for example, a synthetic resin molded article. Can be done automatically.

FIG. 3 is a work process diagram illustrating a process of creating a color sample image representing an embodiment of the present invention. Front view of display screen displaying color sample images Schematic configuration diagram showing a method of obtaining shape characteristic information of the target article Schematic configuration diagram explaining surface normal vector which is shape characteristic information

Explanation of symbols

10 Sample article 20 Color sample plate of individual colorant (smooth)
22 Mixed Color Image 30 Color Sample Image 40 Display Screen 42 Color Sample Image I Illumination Vector
q surface normal vector v line-of-sight vector

Claims (1)

A method for toning a colorant for coloring a target article with a target color,
For each of a plurality of colorants used for toning, a colorimetric sample colored with a colorant and having a smooth surface is measured, and color characteristic information including spectral reflectance of the colorant is obtained (m) When,
From the color characteristic information of the individual colorant obtained in the step (m), a process (n) for obtaining color characteristic information of the mixed colorant when blended in combination with a plurality of colorants used for toning;
By applying the method of creating colored article color sample below, obtained from the color characteristic information of the color mixing coloring agent obtained by the process shape characteristic information associated articles obtained in (b) and the step (n) Displaying the color sample image on the display screen of the image display device;
Step of evaluating comparing the color and object color of the displayed color sample image in the step (o) and (p),
Based on the evaluation in the step (p), by changing the combination formulation of the plurality of the coloring agent in the step (n), Engineering as a step of repeating the step (p) from (o) (q),
A method for toning a colored article, comprising :
Here, the preparation method of the color sample for colored articles is as follows.
A method of creating a color sample for evaluating an expression color in a coloring state of an object article to be colored by a coloring agent,
The color swatch is a color swatch composed of a colored image displayed on an image display device,
A step (a) of photographing at least a surface of a sample article having a surface shape in common with the target article under a plurality of conditions in which a relative positional relationship between an illumination direction and a photographing direction is different;
(B) calculating the shape characteristic information including the surface normal vector and the spectral reflectance in each pixel by performing arithmetic processing on the information of the image photographed under a plurality of conditions in the step (a);
Step (c) for obtaining color characteristic information including the spectral reflectance of the colorant by measuring a colorimetric sample that is made of the same material as the target article, is colored with a colorant that creates a color sample, and has a smooth surface. When,
The shape characteristic information obtained in the step (b) and the color characteristic information obtained in the step (c) are synthesized, and the surface having the shape characteristic information is colored with the color characteristic information. A step (d) of displaying, on the display screen of the image display device, a color sample image composed of a colored image of the virtual object;
A method for producing a color sample for a colored article, comprising:

Images