JPH0749224A - Inspection method for material surface - Google Patents

Abstract

PURPOSE:To properly judge the decorativeness of a building material such as a tile by detecting at least color at many points on material surface, and making comparative judgement about the extent of color dispersion. CONSTITUTION:Regarding the visual observation of the surface of a material like a tile, a rule of thumb tells that irregular surface is all the more decorative, compared with smooth surface, and a dark color system becomes all the more decorative in terms of the brightness of color. Also, the rule tells that decorativeness increases all the more, when many spot zones with a remarkable difference in the brightness of color or chormaticity from a surrounding area are scattered, the decorativeness increases. Thus, a white tile having smooth surface becomes extremely poor in terms of surface decorativeness. On the other hand, the surface of a building material cut out from granite and flattened has extremely high decorativeness. The surface decorativeness of such a material can be easily and properly evaluated on the basis of the extent of color dispersion as one of evaluation procedures on the basis of a physical quantity obtainable as the result of physical detection.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting the decorativeness (texture) of the surface of a member (particularly a building material such as tile).

In recent years, various finished surfaces such as bright and glossy matte finishes, matte matte finishes, transparent glazes and thin glazes have been developed and used. These finishing surfaces are intended to additionally give a high quality and high quality feeling to the tile surface, and are considered to reflect the user's high-class orientation.

[0003]

It is said that the method of inspecting or evaluating the high-quality feeling of the finish of the tile surface, especially the decorativeness (various taste) depends largely on the visual sense of the inspector, so that there are large differences among individuals. There was a problem.

An object of the present invention is to provide a method for inspecting a surface of a member such as a tile, which can accurately determine the decorativeness of the surface of the member.

[0005]

According to a first aspect of the present invention, there is provided a method for inspecting a member surface, which detects at least a color at a large number of points on the member surface, and determines that the larger the degree of color variation is, the greater the decorativeness is. It is characterized by doing so.

According to a second aspect of the present invention, the member surface inspection method detects the lightness L and the chromaticities a and b at many points on the member surface, and calculates ΔE (σ) value and C _{a, b} value from them. ,
The center line average roughness Pa of the surface is measured at each point, and ΔE (σ), C _{a, b} , Pa and L are
It is determined that the larger (σ) is, the higher the decorativeness is, the smaller C _{a, b} is, the higher the decorativeness is, the larger Pa is, the higher the decorativeness is, and the smaller L is, the higher the decorativeness is. It is a feature.

However, ΔE (σ) = √ (L (σ) ² + a (σ) ² + b (σ)
² ) L (σ): Standard deviation of measured L value a (σ): Standard deviation of measured a value b (σ): Standard deviation of measured b value L, a, b: JIS Z 8729 L star, a star, and b star values specified in C _{a, b} : Saturation C star specified in JIS Z 8729, C _{a, b} = √ (a ² + b ² ) Pa: According to JIS B 0601-1982 The centerline average roughness.

FIG. 1 shows the L star, a star, and b star of the present invention entered in the Lab colorimetric chromaticity diagram. A color tone diagram is shown in FIG.

[0009]

[Function] When the surface of a member such as a tile is visually observed, the following phenomenon is known as a rule of thumb.

As compared with a slippery surface, a more uneven surface has a higher decorativeness.

Regarding the lightness, the darker the color, the higher the decorativeness.

The larger the number of spot-like areas, such as scattered points, where the lightness or chromaticity is significantly different from the surrounding area, the higher the decorativeness.

For example, a white tile having a smooth surface has very poor surface decoration. On the other hand, plate-shaped building materials made from granite have extremely high surface decoration.

The present invention evaluates the decorativeness of the surface of such a member on the basis of the physically detected physical quantity.

According to the first aspect, the decorativeness is easily evaluated by the degree of color variation.

In the second aspect, the lightness, the hue, and the surface roughness are added to the degree of color variation, and the evaluation is performed with higher accuracy.

[0017]

[Example] Measurement of lightness, hue and surface roughness and calculation of ΔE (σ) Colorimeter ( CR-241 manufactured by Minolta Camera Co., Ltd.)
And L, C _{a, b} are 45 ° illumination, vertical light reception, and spot diameter 0 at the measurement point for 26 types of tiles manufactured by Inax Co., Ltd. using a spectral colorimeter SZ5Σ80 (φ30 mm) manufactured by Nippon Denshoku Industries Co., Ltd. The L star, a star, b star value and C _{a, b} value were measured at 0.3 mm. The number of measurement points is 21 for each tile.

The ΔE (σ) value was calculated from the 21 points of data.

A surface roughness meter s manufactured by Tokyo Seimitsu Co., Ltd.
The centerline average roughness of the surface was measured using urfcom 1500A.

Table 1 is a list of product numbers of tiles, and Table 2 is a list showing measured values and calculated values.

The subject's decorativeness (texture)
Evaluation The decorativeness of each of the 26 types of tiles was evaluated by 30 subjects. About this evaluation result,
The rank scale was calculated by the synthetic standard method proposed by Guilford (psychometric method: Baifukan). It is known that the scale obtained by this method is in good agreement with the method that assumes paired comparison for rank evaluation.

Table 3 shows the calculation results of this rank scale.

FIG. 3 shows the L value, C _{a, b} value, Pa value, ΔE (σ), and the texture of the subject, in contrast to the physical quantity and the subject evaluation . As shown in FIG. 3, the lower the L value, the higher the texture.
It is recognized that the higher the value, ΔE (σ), the higher the texture feeling. However, it turns out that the correlation is not very strong.

Then, next, T = 6.466 + 0.1971 ΔE (σ) −0.07
When the texture feeling index T defined by 81C _{a, b} +0.0451 Pa-0.039L was compared with the texture feeling of the test subject, as shown in Table 3 and FIG. 4, a very high correlation was recognized. This multiple correlation coefficient R
= 0.911.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3]

[0028]

As is apparent from the above examples, the texture of the surface of the member can be evaluated to some extent from the degree of color variation (ΔE (σ)) of the member, and in particular ΔE
When not only (σ) but also C _{a, b} , Pa and L are comprehensively considered, it becomes possible to evaluate the texture feeling with considerably high accuracy.

According to the present invention, it is possible to accurately check the finish of the surface of a building material such as a tile manufactured on a manufacturing line, and to evaluate the texture of a newly designed building material.

[Brief description of drawings]

FIG. 1 is a Lab colorimetric chromaticity diagram of JIS Z 8729.

FIG. 2 is a color tone diagram of JIS Z 8729.

FIG. 3 is a correlation diagram showing a measurement result in an example.

FIG. 4 is a correlation diagram showing a measurement result in an example.

Claims (2)

[Claims] 1. A method for inspecting a surface of a member, wherein at least colors are detected at a large number of points on the surface of the member, and it is determined that the decorativeness is higher as the degree of variation of the colors is larger. 2. The lightness L, at a number of points on the surface of the member,
The chromaticities a and b are detected, ΔE (σ) values and C _{a, b} values are calculated from these, and the center line average roughness Pa of the surface is measured at each point to obtain ΔE (σ), C _{a , b} , Pa and L, the larger ΔE (σ) is, the higher the decorating property is, the smaller C _{a, b} is, the higher the decorating property is, and the larger Pa is, the higher the decorating property is,
A method for inspecting a member surface, wherein the smaller the value, the higher the decorativeness. However, ΔE (σ) = √ (L (σ) ² + a (σ) ² + b (σ)
² ) L (σ): Standard deviation of measured L value a (σ): Standard deviation of measured a value b (σ): Standard deviation of measured b value L, a, b: JIS Z 8729 L star, a star, and b star values specified in C _{a, b} : Saturation C star specified in JIS Z 8729, C _{a, b} = √ (a ² + b ² ) Pa: According to JIS B 0601-1982 The centerline average roughness.