JP3742633B2 - Classification and arrangement of metallic paint colors - Google Patents

Description

  The present invention relates to a method for determining a representative color of a metallic paint color whose color changes depending on a viewing angle, a method for organizing and classifying metallic paint colors, and a computer graphic device. Furthermore, the present invention calculates a representative color of the metallic paint color as a Hue-Tone (Hue Tone) value, and arranges a paint color computer graphic of the metallic paint color showing the texture on the Hue-Tone chart, The present invention relates to a computer graphic device that displays simultaneous color classification and texture.

  The present invention includes various bright materials such as aluminum pieces, mica pieces, plate-like iron oxide, etc. in the coating film, and can uniquely determine the representative color of the paint color that varies in color depending on the angle to be observed. Color classification and organization are possible, and color search by computer is possible. Furthermore, a design tool using a computer that can simultaneously evaluate color and texture by superimposing computer graphics with texture is provided.

  In recent years, as a characteristic of the color of automobile exterior coating, metallic paint colors including various glitter materials (aluminum flakes, mica flakes, graphite, etc.) dominate. The color of the metallic coating color changes depending on the observation angle and expresses a metallic feeling, a pearl feeling, and a bicolor property (an effect that looks more than two colors depending on the angle), which is referred to as a texture. The Munsell value and the Hue-Tone value have long been used as a method for chromatically classifying the outer panel color of an automobile.

  In the case of a solid paint color, it was possible to classify colors with a color chart system created with solid pigments. However, it is difficult to extract a representative color from a metallic paint color whose color varies depending on the observation angle. As a method of classifying colors other than solid colors, methods for classifying colors with angle dependency for the purpose of pearl classification have been reported (Japanese Patent Laid-Open Nos. 56-061635 and 61-230778). It could not be applied to various colors like the top coat color.

  For this reason, conventionally, designers illuminate a metallic paint color one by one with a light source, visually observe the color change from highlight to shade, and create a representative color in the head. After that, the Hue-Tone value was finally determined by comparing with a color chart of a commercially available Hue-Tone chart. However, this method is too time consuming and has the disadvantage of varying values depending on the designer being evaluated.

  Also, when searching for colors that you image from a huge number of paint colors created in the past, it takes the man-hours described above for each color, so you can search by hitting from thousands of color charts depending on your memory color There was no method other than to do, and the color search was not practically possible.

  When the above problems are arranged, the most important point is how to determine the representative color of the metallic paint color whose color changes depending on the angle. If a colorimetric approach is taken and the colorimetric value of which angle can be adopted to represent a representative value of the paint color, the color can be used as an HVC or Munsell color chart system often used in the design field. A commercially available Hue-Tone value can be calculated, and a value that matches this value may be used as an approximate color of an image.

According to the present invention, in order to solve the problem as described above,
Determining the representative color of the metallic paint color,
Calculating a Hue-Tone value of the representative color;
Generating a paint color computer graphic showing the optical properties of the metallic paint color over a predetermined observation angle range;
A metallic paint color comprising creating a paint color map by arranging the paint color computer graphic on a hue-tone value of the representative color in a hue-tone chart on a monitor of a computer system A sorting and sorting method is provided.

According to the present invention, in order to solve the problem as described above,
Means for determining a representative color of the metallic paint color from colorimetric values of a plurality of observation angles of the metallic paint color;
Means for converting the representative color into a Hue-Ton value;
Means for generating a paint color computer graphic of the metallic paint color from colorimetric values of a plurality of observation angles of the metallic paint color;
There is provided a computer graphic apparatus comprising: means for arranging and displaying the paint color computer graphic on a Hue-Tone value on a Hue-Tone chart generated on a display.

  The most important technique of the present invention is that, when an arbitrary metallic paint color is given, from this multi-angle measurement value, if this paint color adopts a number of color measurement values, the representative color of the metallic paint color This is a method of calculating whether or not This core technique is referred to as a “metallic color representative color determination algorithm”.

  As a result of repeated visual experiments using metallic paint colors including various glitter materials as a sample, research has succeeded in developing a “representative color determination algorithm for metallic paint colors” that satisfies most designers.

  In other words, when constructing a computer system that searches for a design image color of a metallic paint color that includes various glitter materials and changes variously depending on the observation angle, if there are the following three points, the image color Hue-Tone A value can be calculated, and an arbitrary Hue-Tone value can be retrieved from the multi-angle reflectance measured in the past using this value.

  a) A hard disk for storing multi-angle colorimetric values of metallic paint color.

  b) “Representative color determination algorithm for metallic paint color” for calculating the angle of metallic representative color from the multi-angle data.

  c) An algorithm for calculating a representative color into a Hue-Tone value.

  Furthermore, if the following two points are added, the computer graphic can be pasted on the calculated Hue-Tone value on the Hue-Tone chart output on the computer graphic monitor, and thereby Hue which is a chromatic color classification. -A completely new computer graphic capable of simultaneously evaluating Tone value and texture is obtained.

  d) A computer graphic representing the change in color for each change in metallic angle from the multi-angle reflectance.

  e) Computer graphic of Hue-Tone chart.

(Determination of representative colors)
The algorithm for determining the representative color of the metallic paint color is as follows.

  Generally, the gloss distribution due to the coating structure and the angle change of the metallic coating color is as shown in FIG. Scale-like glittering materials (flakes such as aluminum and mica) are arranged in parallel in a color base containing a chromatic pigment or dye. The structure of the metallic coating film may be a so-called color clear coating color in which a color clear is coated on a metallic base containing no chromatic organic pigment.

  The highlight side has a high reflectance and is bright due to the reflection on the surface of the glitter material, and the glitter of the glitter material is felt. The shade side is the angle at which the color of the pigment in the color base develops, and the brightness is lower than the highlight.

  On the other hand, various Hue-Tone charts are currently published. In this aspect, as a Hue-Tone chart, the laminate coating of Japan Color Design Laboratory Co., Ltd., which is widely used in the field of domestic color design of automobiles. A version of M * M Chart II (hereinafter referred to as M * MC) is used. The reason why the laminate plate of M * M Chart II was used is that the laminate coating is close to the full gloss of the automobile top coat color.

  In this M * MC, as shown in FIG. 3, the horizontal axis is a total of 44 scales of 43 hues from red 2.5R to purple 10RP and achromatic N (18 colors), and the vertical axis Tone is 25 scales. 1093 color charts (43 × 25 + 18 = 1093) are arranged in the two-dimensional table divided by.

  Using a metallic paint color as a sample and a color designer engaged in the design of a car top coat paint as a test subject, a visual sensory experiment is performed, and a representative color for each sample is determined using a commercially available M * MC.

  Next, in order to calculate which observation angle this representative color corresponds to, the metallic paint color is measured from, for example, five observation angles with a multi-angle spectrophotometer, and described in Japanese Patent Application No. 8-177171. The angle indicating the smallest color difference (JIS Z 8730) was calculated using the formula for predicting the spectral reflectance at an arbitrary angle, and the angle giving the representative color of the metallic paint sample was calculated. This is called a representative angle D.

  Actually, since the representative angle D of any given metallic paint color must be predicted and calculated from the colorimetric values, an expression for predicting this angle is examined, and finally the function type of Expression (1) is used. We found that the representative angle D can be calculated with high accuracy.

D = a1 * V1 + a2 * V2 + b ... Formula (1)
Here, V1 is the sharpness calculated from the colorimetric value on the highlight side. Here, referring to FIG. 1, the highlight side is preferably in the range of 10 to 30 degrees, more preferably 22 to 28 degrees. Crispness index is commonly referred to as sharpness in an amount calculated by the lightness L * and chroma c * color formula as defined in JIS Z 8729 (2).

V = sqrt (L * ^ 2 + c * ^ 2) ... Formula (2)
V2 is the sharpness calculated from the colorimetric value on the shade side. An angle in the range of 35 to 55 degrees, more preferably an angle of 40 to 50 degrees is desirable. The coefficients a1, a2, and b are multiple regression coefficients, and can be easily obtained by multiple regression analysis with the representative angle D of the metallic coating color obtained visually as an objective variable and V1 and V2 as explanatory variables.

  That is, a1, a2, and b of the formula (1) are determined from a plurality of samples of metallic paint color, and V1 and V2 of the formula (1) are determined from the metallic paint color for obtaining the representative angle D as described above. D of this metallic paint color is obtained.

  In this way, the representative angle D is determined, and the reflectance at that angle is determined by using the formula for predicting the spectral reflectance at an arbitrary angle described in the specification of Japanese Patent Application No. 8-177171, and is defined in JIS Z 8729. The Lab * value of the representative color was obtained by the method described above.

(Determination of Hue-Tone value)
Next, in order to convert the Lab * of the representative color into the Hue-Tone value, the color difference between the measured value Lab * of the M * MC color chart and the Lab * of the representative color is sequentially calculated, and the color chart that gives the minimum color difference is calculated. A Hue-Tone value was determined and used as a Hue-Tone value of a representative color of the metallic paint color.

(Generation of paint color computer / graphic)
A metallic paint color computer graphic is a display on a computer system monitor in which the optical properties of the metallic paint color are generated using the computer's image processing technology.

Paint color computer-Gurafuikku, for example, as shown in FIG. 1, at an incident angle of 45 degrees, at an angle from specular reflection, optical in the observation angle range of up to 10 degrees (highlighted) from 1 1 0 degrees (Shiedo) For example, a rectangular display portion 6 in the Hue-Tone chart 5 in the monitor of the computer system as shown in FIG. In this rectangular display portion, a color which is an optical property in an observation angle range from 10 degrees (highlight) to 1 10 degrees (shade) is displayed from top to bottom. Preferably, the code number of the metallic paint color is displayed above the rectangular display portion.

  This metallic paint color computer graphic can be generated from the spectral reflectance obtained by measuring from 10 degrees to 110 degrees in increments of 1 degree, for example, with a variable angle spectrophotometer. Alternatively, the metallic paint computer graphic has a spectral reflectance measured under the five-angle condition of the metallic paint color and a spectral measurement measured under the five-angle condition in accordance with the teaching content of Japanese Patent Application No. 8-177171. It can also be generated by determining the spectral reflectance at a desired angle of the metallic paint color based on the regression equation and regression coefficient calculated by the reflectance.

(Create a color map)
The Hue-Tone chart created on the computer system monitor, for example, M * MC, plots the Hue-Tone values of the representative colors determined as described above, and the plot points are generated as described above. Overlay the painted color computer graphic.

  The computer graphic obtained by the above method is a new computer graphic that can simultaneously evaluate the Hue-Tone value, which is the color and design color classification of metallic paint colors, and the texture, and the field of color design that handles metallic paint colors. It becomes a design tool for developing paint colors that are particularly effective.

(Computer graphic device)
A computer graphic device according to a preferred embodiment of the present invention will now be described with reference to FIG.

  As shown in FIG. 2, the computer graphic apparatus measures the metallic coating film 1 with a portable spectrophotometer 2, takes the obtained multi-angle reflectance into the computer 3, and obtains an equation ( Using 1) and formula (2), an angle giving a representative color of an arbitrary metallic paint color is obtained, the reflectance of the angle is obtained, converted to Lab *, and the color chart of the Hue-Tone chart already measured The color difference from the colorimetric value Lab * is calculated, the Hue-Tone value of the representative color of the metallic paint color is calculated, and the computer graphic of the metallic paint color is superimposed on the Hue-Tone chart on the computer monitor 4. . By using this computer graphic device, it is possible to create a new graphic that can simultaneously evaluate the color classification and design color classification and the texture of the metallic paint color by computer graphic in a short time and with a small device. It was.

(Determination of representative colors)
First, the procedure for determining the representative color of the metallic paint color will be described.

  A wide range of colors including metallic glitter materials (aluminum flakes, mica flakes, plate-like iron oxide, fine particle titanium, etc.) and 32 metallic paint colors with a wide range of textures were prepared as samples. Next, a visual sensory experiment was conducted using 17 color designers and technicians related to colors and coloring materials. For each sample color, which Hue-Tone value of M * MC is the representative color of the sample is answered, and after aggregation, the average representative color of 17 people was determined.

  On the other hand, colorimetric values were measured using a portable variable angle spectrophotometer MA68 manufactured by X-Rite, USA. Measurement angle is 15 degrees and 25 degrees of specular reflected light (highlight side) with respect to 45 degrees incidence, 45 degrees of front, 75 degrees of bottom color (shade), and 32 colors of metallic coating at 110 degrees The spectral reflectance of each color sample was obtained.

  Next, the angle closest to the representative color was determined by using the formula for predicting the spectral reflectance at an arbitrary angle described in Japanese Patent Application No. 8-177171.

  Then, in order to apply this angle to an arbitrary metallic paint color, a multiple regression analysis was performed, and Expression (3) was obtained from the function type of Expression (1).

D = 0.0612 * V1 + 0.253 * V2 + 15.11 Formula (3)
The multiple correlation coefficient of this multiple regression equation is 0. It was very high as 8, and it was confirmed that the angle giving the metallic representative color could be estimated with high accuracy. For the sharpness V1 and V2, here, measured values of 25 and 45 degrees were adopted, and brightness L * and saturation c * were calculated using JIS Z8729.

  Next, an arbitrary metallic coating color A1 is measured with the spectrophotometer shown in FIG. 2, and the sharpness V25, V45 is calculated from the measured values of 25 degrees and 45 degrees using the equation (2). Next, a representative angle giving a representative color of the metallic color was calculated using the formula (1).

And the reflectance in a representative angle was computed using the formula which estimates the spectral reflectance of the arbitrary angles described in the said Japanese Patent Application No. 8-177171 specification, and Lab * value was obtained using JISZ8729.

In this way, the Lab * value of the representative color A2 of the arbitrary metallic paint color A1 was determined.

(Determination of Hue-Tone value)
Lab * of 1098 colors of M * MC color chart measured in advance by a 45/0 degree spectrophotometer X968 manufactured by X-Rite, USA, is stored in a computer storage device as a database.

  Next, the color difference between the Lab * value of M * MC in the database, the Lab value of the representative color A2 determined as described above, and * is calculated by the method of JIS Z8730, and the M * MC color chart that gives the minimum color difference A Hue-Tone value of the representative color A2 was set as a Hue-Tone value of A2.

  Table 1 shows the representative colors of the four metallic coating colors that were visually observed and the representative colors that were calculated.

  In Table 1, from the left, 1) no: sample number, 2) 45/0 degree measurement color L * a * b *: incident light 45 degree, L * a * b * value of measurement color at 0 degree light reception, 3 ) Visual color: representative color of metallic paint color determined from visual experiment by 6 people, this is the correct answer 4) Answer of formula (1) 5) dM: Visual color on Hue-Tone chart (correct answer) The distance between and the calculated color. Smaller is better. If 0, the Hue-Tone value of the visual color and the calculated color match. 6) Judgment: ◎ completely matches the visual color, ○ matches within the visual variation range, and x indicates a large error. 7) Comparative example: Value calculated using Lab * colorimetric values under 45/0 degree condition, which is a solid colorimetric standard (Hue-Tone value that minimizes the color difference). Especially light gray no. 2 to 4 are dark values, and the determination is x. In other words, when the 45/0 degree colorimetric value is used as it is, 45/0 degree is close to the shade side, and thus becomes a considerably dark value. On the other hand, the highlight side is slightly observed visually. For this reason, the determination was x as described above.

  As can be seen from Table 1, a considerable satisfactory level of satisfaction could be obtained.

(Generation of paint color computer / graphic)
A coating color computer graphic was generated from the spectral reflectance obtained by measuring the above-mentioned arbitrary metallic coating color A1 in steps of 10 degrees to 110 degrees with a variable angle spectrophotometer. According to the teaching content of Japanese Patent Application No. 8-177171, this paint color computer graphic is determined by the spectral reflectance measured under the five-angle condition of the metallic paint color and the spectral reflectance measured under the five-angle condition. It can also be generated by determining the spectral reflectance at a desired angle of the metallic paint color based on the calculated regression equation and regression coefficient.

(Create a color map)
The Hue-Tone value A3 of the representative color A2 obtained as described above for the arbitrary metallic paint color A1 is plotted on the Hue-Tone chart 5 generated in the monitor of the computer system as shown in FIG. The paint color computer graphics generated as described above were superimposed.

  In the same procedure as described above, Hue-Tone values of representative colors of other metallic paint colors were plotted, and the paint color computer graphic of the metallic paint was superimposed.

  In this manner, a plurality of metallic paint computer graphics are arranged to create a metallic paint color map as shown in FIG.

The figure which shows the gloss distribution by the coating-film structure of a metallic coating color, and a bend. 1 illustrates a computer graphic device according to one embodiment of the present invention. The figure which plotted the metallic paint color 32 colors on the Hue-Tone chart, and has arrange | positioned the three-dimensional computer graphic.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metallic coating film 2 Multi-angle variable angle spectrophotometer 3 Computer 4 Monitor 5 Hue-Tone chart 6 Display part of paint color computer / graphic

Claims (1)

A representative color determining means for determining a representative color of the metallic paint color, which is one color at an angle at which the representative color of the metallic paint color is most likely to represent the metallic paint color according to a predetermined equation,
Determining the representative color of the metallic paint color
Obtaining the representative angle D from the following equation (1);
D = a1 × V1 + a2 × V2 + b (1)
V1 is the sharpness calculated from the colorimetric value on the highlight side, and V2 is the sharpness calculated from the colorimetric value on the shade side,
The sharpness V is an amount calculated from the following formula (2) from the lightness L * and the saturation c *;
V = sqrt (L * ^ 2 + c * ^ 2) ... Formula (2)
The coefficients a1, a2, and b are multiple regression coefficients obtained by multiple regression analysis with the representative angle D of the metallic paint color obtained from the visual observation as the objective variable and V1 and V2 as explanatory variables,
Representative color determining means including predicting the reflectance of the representative angle D obtained from the above formula (1) to determine the representative color of the metallic paint color ;
Means for converting the representative color into a Hue-Tone value;
Means for generating a paint color computer graphic showing optical properties over a predetermined observation angle range of the metallic paint color ;
A computer graphic apparatus comprising: means for arranging and displaying the paint color computer graphic on the Hue-Tone value of the representative color on the Hue-Tone chart generated on a display.

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