KR940004653B1 - Colour rendering display device - Google Patents

Abstract

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Description

Object color judging device

1A and 1B are diagrams showing an example of a screen displayed by the display device of the present invention.

2 is a block diagram showing an embodiment of the present invention, in which L.a.b is indicated.

3A and 3B show a flow chart displaying the operation of the embodiment of FIG.

4 and 5 show examples of display.

6 is a diagram showing an example of a memory map of RAM.

* Explanation of symbols for main parts of the drawings

1: CPU 3: Colorimetric Device

4: RAM 5: CRT

P: Image of the coordinate to be measured Q: Permissible limit line

1A, 1C, 1F: Displayed phase.

The present invention relates to an apparatus for determining color difference and color rendering of an object color.

Several methods of displaying object colors are known (eg Lab HVC, RGB indicators), and they are already used in each area, but their indicators are the starting point for displaying colors and the interrelationships between the two colors. It is already evident in the literature that there are not enough relational expressions for relations, ie considering color rendering).

On the other hand, in determining the color of an article in commerce, etc., it is necessary to determine whether or not the presented color is within a desired color range.

A) the use of the object (even if the same red is different from the red for clothing and the red of other objects)

B) color balance with the article in combination with the article;

C) person's sign

D) technical difficulty;

Depends on

Conventionally, this kind of judgment is based on human intuition, but the criterion is extremely ambiguous, subjective and requires experience.

The conventional colorimetric device outputs numerical data such as a lab indicating the color of an object, so that once the data is viewed, it is impossible to determine whether or not the color of the object is within an allowable limit. Since the color does not match the value judgment of the actual product, such a colorimeter cannot be used in practice.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a device capable of displaying coordinates indicating a color of a measurement target, a line indicating an allowable limit, and coordinates for various light sources on the same chromaticity diagram. .

The apparatus for determining the object color of the present invention includes display means for displaying an image for displaying coordinates representing a measurement target color on a chromaticity diagram, display means for displaying an allowable limit line for displaying an allowable range of color differences between two colors; Display means for displaying the coordinates of the respective colors for different light source types (for example, sunlight, fluorescent lamps, etc.) on the chromaticity diagram is possible, and displays such as Lab, HVC, RGB, etc. are possible.

Normally, the operation is performed separately from the display of the chromaticity and the allowable range for each light source, but it is naturally possible to display both functions simultaneously.

In the display device, for example, as shown in FIG. 1- (1), the color of the article with respect to the light source C (sunlight) and the light source A (tungsten bulb method, light source F (fluorescent lamp)) is displayed on the coordinates of the chromaticity diagram. It is represented as 1C, 1A, 1F.

For example, in the example of FIG. 1- (2), the image P which shows the coordinate of a measurement object and the original limit line Q are displayed on the chromaticity diagram, and it measures in the range of this limit line Q. The degree of difference between the color of the measurement object and the desired color is displayed depending on whether or not the object P exists or not, thereby determining whether or not the shipment is possible.

Hereinafter, an embodiment of the present invention will be described.

Example 1

In FIG. 2, 1 is a CPU, 2 is a keyboard, 3 is a colorimetric apparatus, 5 is a CRT display, 6 is a printer, and 7 is an interface.

The CPU 1 is equipped with a program displayed in FIG. 3- (1) for displaying the chromaticity diagram shown in FIG.

The colorimetric apparatus 3 outputs a signal representing the color by projecting light onto the measurement object, and the signal is an L.a.b value that can be obtained from the reflected light from the measurement object for each wavelength of the projected light.

The RAM shown in the table below is stored in the RAM in the CPU 1.

In the above apparatus, at step S1, the standard sample is color-coded with the colorimetry apparatus 3, and its L.a.b value is written into the RAM. Next, in step S2, the color of the measurement object (sample) is measured by the colorimetry device 3, and the L.a.b is written into the RAM.

In step S3, the colorimetric value for each light source of the sample and the measurement target is calculated. An associative method is based on the calculation formula prescribed | regulated to JIS 873/1980, for example.

In step S4, color difference correction for each light source of the standard sample is performed.

Subsequently, in step S4, the difference between the canine sample and the L.a.b for each light source to be measured is calculated.

The result of the calculation is displayed on the screen of the CRT 5 as coordinates on the chromaticity diagram as shown in FIG.

As a display example, as shown in FIG. 4, the coordinates of the standard sample Lab for one light source are displayed at the Po point, and the coordinates of LC, aC, and bC of the measurement target for each light source C and A are Pc, and L _A , a The coordinates of _A and b _A may be displayed on the CRT 5 by P _A. As shown in FIG. 5, P _C and P _A may be displayed by shifting the coordinates of the standard sample to the origin.

By looking at this indication, it can be seen at first glance how the book object is generated with respect to the light sources C, A, and F.

In each of the examples described above, one case of the measurement object is displayed, but the coordinates of a plurality of measurement objects may be displayed at the same time.

EXAMPLE

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

The CPU 1 is equipped with the program shown in FIG. 3B for displaying the chromaticity diagram shown in FIG.

The color measuring device 3 transmits light to the object to be measured and outputs a signal representing the color thereof. The signal is obtained from the reflected light from the measurement object for each wavelength of the projected light. b value.

In the RAM 4, as shown in FIG. 6, the area 4A for storing the color data of the color sample, the area 4B for storing the color data of the tolerance sample, and the color data (performance data) to be measured 4 C of memory areas are provided.

The storage format and the contents of the data are as shown in the first table.

TABLE 1

The CPU 1 measures the measured value of the measurement object as L. a. It has the function to display the point on the coordinate of b system and draw the tolerance line.

Tolerance lines are made, for example, by the following method.

Draw the limit line

As the expression of the color, the CIE-Lab system is used as an example.

(1) Make the difference between the sample and the limit sample Lab (dL, da, db)

dL ₁ : Difference between L value of limit sample i and L value of color sample

da ₁ : Difference between a value of limit sample i and a value of color sample

db ₁ : difference between the value of limit sample i and the value of color sample

(i = 1,2, ... m, m> 0)

(a) Example of limit of dL value

When one or each of the positive and negative parts are combined on the dL straight line or positive or negative, a line is drawn with symmetry of the origin.

(b) da, db is the limit line example

There are thresholds (da ₁ , db ₁ ), (da ₂ , db ₂ ) in the (da, db) plane, and to draw a curve between these two points

Leave it as.

Distance from origin (a, b value of color sample) to (da ₁ , db ₁ )

Check each sign from the da axis to the point (da ₁ , db ₁ ) so that 0≤θ ₁ . Further takes a point so as θ1 <θ _2.

Set the table (X ₁ , Y ₁ ) on the (da, db) plane as

Example of f (j)

Here, if two points (X _j , Y _j ) and (X _{j + 1} + Y _{+ 1} ) (j = 1, 2, ..., n-1) are obtained, a curve is obtained.

If you try to draw Peruup around the origin, take the two-point case as an example: (da ₁ , db ₁ ), (da ₂ , db ₂ ) in a curve and then (da ₂ , db ₂ ), ( da ₁ , db ₁ ) to form a curve.

However, the angle with the axis of the point (da ₁ , db ₁ ) at this time is assumed to be 2π added to the first angle obtained.

The CPU 1 also has a function of dividing the range within the range limited by the allowable limit line into several. An example of division is shown below.

(1) equal division

Use l ₁ and l ₂ to find the limit line.

For example, when dividing into three parts

Draw l ₁ , l ₂ in the formula of the limit line as l _{1 '} , l _2' and draw the limit line as l ₁ ^" , l ₂ ^" at equal intervals inside the first limit line (near the origin). It is divided into three.

(2) Inequality interval division

To draw a curved line is left as the distance l ₁ ^', l _^2' from the reference point in place of l _1, l _2.

Where 0 <a _{1 <1} when being in the inner side of the limit line 1 _<1 when a is the outside.

Generally up to a <3. In the apparatus having the above-described configuration, when the standard sample is color-coded by the colorimetric device 3, this colorimetric data is input to the CPU 1 in step S1. The colorimetric result is stored in the RAM 4 at step S2. In step 3, the presence or absence of a limit is determined. If YES, the flow advances to step S4 to measure the limit sample set in the colorimetric device 3, and the colorimetric result is stored in the RAM 4 at step S5. do. If NO, the flow advances to step S6 where color measurement of the object to be measured is performed by the colorimeter 3, and the color data is written into the RAM 4 in step S7.

When there are a plurality of measurement objects, steps S6 to S8 are repeated.

After the colorimetry is finished, the process proceeds from step S9 to step S10, where standard sample data and limit sample data are read from the RAM 4, and the limit curve Q is calculated by the above calculation. When there is a command to display the dividing line, the dividing by the above calculation is calculated and the dividing lines Q ₁ , Q ₂ ... are calculated.

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

On the display screen of the CRT 5, the coordinate P and the limit line Q which display colorimetric data as shown in FIG. 1B are displayed. The dividing lines Q ₁ and Q ₂ are also displayed as desired. In addition, the printer 6 prints the above-described image P and lines Q, Q ₁ and Q ₂ on a predetermined difference art.

If the coordinate P of the measurement target is in the range of (Q ₁ ), the color of the measurement target is closer to the color sample than the limit line Q, and if it is within the range of Q ₂ , it is closer to the color sample. have. If the P point is outside the range of the limit line Q, the color of the object to be measured is outside the allowable limit. In addition, the present invention is not limited to the above-described embodiment, and color coordinates and tolerance lines of the measurement target may be drawn using various chromaticity diagrams.

The effects of the present invention are approximately as follows.

1. As described above, according to the present invention, since the color of the article for various light sources is simultaneously displayed on the chromaticity diagram, the color change can be seen at a glance and the change can be seen as an objective.

2. The image (P) and the tolerance line (Q) indicating the coordinates of the color of the measurement object obtained at the colorimetric position can be displayed on the display device. Therefore, it is necessary to determine whether or not the color of the measurement object is within the tolerance. At the same time, subjective elements such as "intuition" of a person do not enter, so accurate color judgment becomes possible and the degree that experiences are required is small.

In addition, determination of colors that has not been possible in the past can be completely mechanized and does not require an experienced person. If the limit sample can be used as a shipping standard, the quality of the shipment can be judged, and the same level of judgment can be made between internal and external transactions at all times, and the distribution management can be greatly improved. In-plant control limit swatches enable in-process quality control and fully automate the process, including color determinations that were previously impossible.

Claims (2)

An apparatus for determining an object color, comprising: displaying an image on a chromaticity diagram indicating coordinates indicating a color of a measurement target; and a line indicating a permissible range of color differences. An apparatus for judging the color of an object, comprising a color rendering display function for displaying a coordinate position of each color under a different light source to a function indicating a color of a measurement target.

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