JPS60257328A - Color difference deciding device - Google Patents

Abstract

PURPOSE:To mechanize an exact color decision without a man's subjective element by displaying an image for showing a coordinate for indicating a color to be measured, and an allowable limit line for indicating an allowable range of a difference of a color, on a chromaticity diagram. CONSTITUTION:The titled device is constituted of a CPU, a color measuring device, a RAM, a CRT display device, etc. In this state, a color measuring data of a standard sample measured by a color measuring device, a limit sample, and an object to be measured is stored in the RAM. When the color measurement is ended, first of all, a standard sample data and a limit sample data are read out of the RAM, and a limit curve Q is calculated by a prescribed calculating expression. Subsequently, the color measuring data of the object to be measured is read out. Thereafter, a coordinate P for showing the measuring data and a limit line Q are displayed on a CRT display picture. Parting lines Q1, Q2 are displayed as desired. If the coordinate image P of the object to be measured is within a range of Q1, it is decided that a color of its object to be measured is more similar to a color sample than the limit line Q, and if it is within a range of Q2, it is decided that said color is further similar to the color sample. If the point P is outside the range of the limit line Q, it is shown that the color of its object to be measured is outside the allowable limit.

Description

[Detailed description of the invention] Utilization field of industry-1-1 The present invention relates to a color difference determination device.

[Problem with Prior Art 1 Several methods are known for displaying object colors (for example, L, a, b, H, r), C, l(, B, C, R, G).

B el, c), which are already used in various fields, have their starting point in displaying colors;
It is already clear from numerous documents that a sufficient relational expression does not exist regarding the mutual relationship between two colors. ' To determine the color of an article in commercial transactions, etc., is it necessary to determine whether the presented color is within the desired color range? (Even though red is the same, red for clothing is different from red for other items.) The color balance between the item and the item it is combined with differs depending on one person's preference, the level of technical difficulty.

Conventionally, this type of judgment is based on human intuition, but the judgment criteria are extremely vague and subjective, and also requires experience. Conventional colorimetric devices represent the color of the object. Since it is designed to output numerical data such as a and b, it is necessary to look at the data and judge whether the color of the object is within the allowable limit or not. Since color determination based on value does not match the actual value determination of a product, such a color measurement device cannot be used practically.

[Object of the Invention] The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a device that can display coordinates representing the color of a measurement target and lines representing permissible limits on a chromaticity diagram. The purpose is to

[Structure of the Invention] The color difference determination device of the present invention includes a display device that displays an image showing the coordinates representing the color to be measured on a chromaticity diagram and a tolerance limit line representing the tolerance range of color difference. .

On the display device, for example, as shown in FIG. Depending on whether or not there is an image P of the measurement object in , it is determined whether the color of the measurement object is available or not.

[Example] The present invention will be described below with reference to one embodiment.

In FIG. 2, 1 is a CPU, 2 is a keyboard, 3 is a color measurement device, 4 is a RAM, 5 is a CRT display device, 6 is a printer, and 7 is an interface.

The CPU is equipped with a program shown in FIG. 3 for displaying the chromaticity diagram shown in FIG.

The colorimeter 3 projects light onto the object to be measured and outputs a signal representing the color of the object, and the signal is determined from the reflected light from the object for each wavelength of the projected light, a.
This is the IJ value.

As shown in FIG. 4, the RAM 4 includes an area IA for storing color data of color samples, an area 4B for storing color data of permissible limit samples, and an area 4C for storing color data (actual data) of the measurement object. We are prepared.

The storage format and data contents are shown in Table 1.

Table 1 CPUI has the function of displaying the colorimetric value of the measurement object at the coordinates of the a and b system, and the function of drawing a tolerance limit line.

The tolerance limit line is created, for example, by the following method.

Formula for drawing limit line The CIE-Lab system will be described as an example of color expression.

(1) Create a Lab difference between the color sample and the limit sample (dL).

da, db) dLl-L-L, 'cla,=a-a, d
b+=b −1]l gI S , gl S , gI
S=L-1-, da-a-a, db=b-
1], l gIS l gls l1il SdL =
L - L, da = a - a, db = b -
13II 8 mouth S n gll S IT gll
Sdl: 1 of limit sample 1. Difference da between value and L value of color sample
: Difference between a value of limit sample i and a value of color sample db: Difference between 1] value of limit sample i and b value of color sample (i-1, 2, -m, m
>0) (a) Example of limit of dL value On dl-line, draw one line for each positive and negative line, or draw a line symmetrically about the origin when the lines are clustered in positive or negative lines.

(b) Example of limit line of dat db (da, db) Limit point (da,, dl+1) on plane
, (da2゜db2), and to draw a curve between these two points, set: -μ] i - 1 = 1.2.

・From the origin (color sample a, l values) to (da, dl)
) to 1 Distance・Check the sign of the angle from the da axis to the point (da, dl+) and make sure that 0≦θ. Also, take points so that θ1 minus θ2.

Δ(2ρ, -ρ1 80=θ, -θ1 (θ, 〈θ2) (da, cab) Set the coordinates (x,, y) on the plane as shown in the following formula.

(J = 01 1.21...n: 11 is a positive integer)
Example of (j) Here 2. Sada, (x,'l y J) and (×j
+pl'+1) (,1=1+2,...,n-1)
It becomes a curve that connects the.

If you want to draw a closed loop around the origin, take the case of two points as an example. Connect (da,, db,), (da, dl],) with a curved line, then (da7. db, ), (da,, d
b,) are connected with a curved line.

However, the angle of the point (daHdbl) with the da axis at this time is [• 2π added to the initial angle.

Furthermore, CPiJl has a function of dividing a limited range into several parts using a tolerance limit line.

An example of division is shown below.

Method of division [(da, dl]) Plane example 1 (1) When drawing the allowable limit line for equal division, use 1, 12.

For example, when dividing into three equal parts, the limit line equation 1, . 12 to 11゛! , Draw one limit line as ゛,
Also, if you draw a limit line as 11'', te,'', you can divide it into three equal intervals inside the initial limit line (closer to the origin).

(2) Unevenly spaced division! ! = α4. (α Ω, i=1.2) ”1 1
1 1, 1. , l, instead of the distance from the origin),
It is best to draw a curve as β2''.

Here, when 0〈α, ku1, it is inside the limit line, and 1
〈The side of α is the outside.

- Up to about 3 in terms of transport.

In the apparatus having the configuration described in 2 above, when the sample 4 is color-measured by the colorimeter 3, this colorimetric data is input to the CT'U1 in step S1. And the color measurement result is RAM
4 in step S2. In step S3, it is determined whether there is a limit, and if YES, the process proceeds to step S4,
The color of the limit sample set in the colorimeter 3 is measured, and the result of the colorimetry is stored in the RAM 4 in step S5.

If No, the process proceeds to step S6, where the colorimetry of the measurement target is performed by the colorimeter 3, and the colorimetric data is sent to step S7.
Write it to RAM4.

If there are multiple objects to be measured, steps 86 to S8 are repeated.

When the color measurement is completed, the process proceeds from step S9 to step S10, where the standard sample data and limit sample data are read out from the RAM 4, and the limit curve Q is calculated by the calculation described above. When there is a command to display dividing lines, the above-mentioned calculation is performed to display dividing lines Q1, Q2, . Calculate...

Next, in step S12, colorimetric data of the measurement object is read out.

Then, on the display screen of the CRT 5, coordinates P and a limit line Q indicating colorimetric data as shown in FIG. 1 are displayed. The dividing lines Ql and Q2 are also displayed as desired. The printer 6 also prints the above image P and lines Q, Ql, on a predetermined chart.
Q2. Print...

If the coordinate image P of the measurement object is within the range of 01, it can be seen that the color of the measurement object is closer to the color sample than the limit line Q, and if it is within the range of Q2, it is 1f・and even closer to the color sample. I understand.

If point P is outside the range of limit line Q, this indicates that the color of the measurement object is outside the allowable limit.

Note that the present invention is not limited to the two embodiments, and the coordinates of the color of the measurement object and the tolerance limit line may be drawn using various chromaticity diagrams.

[Effects of the Invention] As shown in the double series, the present invention can display on a display device an image (P) representing the coordinates of the color of the measurement target obtained by a colorimeter and a tolerance limit line (Q'). Therefore, it is possible to judge at a glance whether the color of the object to be measured is within the allowable limits, and since there is no subjective element such as "human intuition", it is possible to make accurate color judgments, and it also requires experience. less frequently.

Additionally, color determination, which was previously impossible, can be completely automated, eliminating the need for experienced personnel.

If a limit sample can be used as a shipping standard, it is possible to judge the quality of shipped products, and it is also possible to always make judgments at the same level between internal and external transactions, which can greatly improve distribution management. By using factory control limit samples, it becomes possible to control quality within the process, and it becomes possible to fully automate the process, including color determination, which was previously considered impossible.

[Brief explanation of drawings]

FIG. 1(,) and FIG. 1(I) are diagrams showing an example of an image displayed on the determination device of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 70-chart showing the operation, FIG. 4 is a diagram showing an example of the memory map of the RAM. 1...CPU, 3...Color measurement device, 4...RAM
, '5...CRT P...Coordinate image of measurement target, Q...Tolerance limit line. Patent applicant: Toyobo Co., Ltd., patent attorney: Aoyama Sogai (1 person) Figure 1 (a) Moxibustion master. Moon Figure 1 (b) Decoy H sound Figure 2 Figure 4 Figure 3

Claims (1)

[Claims] (1) A chromaticity diagram; and (2) a display device that displays an image showing the coordinates representing the color of the object to be measured and a line representing the allowable range of color difference.