JP2004109098A - Color characteristics detection for eye, light source and instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easy inspection method capable of surely making a judgement of color reproduction characteristics of an instrument, color characteristics of a light source and color sense of the eye in visual judgement without using a measuring instrument. <P>SOLUTION: Primary standard color chip pieces are matched in metameric color under a specified light source. A judgement is made on whether the eye has a color sense conforming with that of a CIE standard colorimetric observer on the basis of chromaticity (xy value and ab value) obtained by vidual color matching on a color chart on which three primary color ratios are finely changed in vertical and horizontal directions, with CMY ink colors having the same chromaticity but having different spectral curves being set at a center. If the eye does not have the color sense conforming with that of the standard colorimetric observer, the following can be considerably strictly detected by visual sense: the color direction in which a color shift occurs; and color of the light source and further color reproduction characteristics of a film, a digital camera and a scanner. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inspection method for detecting color characteristics of an eye or a light source, and color reproduction characteristics such as color misregistration in device color reproduction of a film, a digital camera, a scanner, or the like, based on visual perception.
[0002]
[Prior art]
Conventionally, to determine color misregistration, there is a method of measuring the chromaticity of a duplicate of a photographed color chart with a spectrophotometer or the like. There has been no method for simply and strictly inspecting color reproduction characteristics such as color misregistration in device color reproduction.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to solve the problem of color characteristics of an individual's eye, color quality of a light source, and color characteristics of device color reproduction by visual sensation easily, which could not be solved by the conventional visual sensation determination method. .
[0004]
In the conventional method, an expensive measuring device was required for the determination. In the earlier application filed by the same applicant (August 14, 2002 / manual correction 19th), how various colors cause color misregistration depending on each eye, each camera, film, and scanner device. In addition, the light source characteristics could not be determined exactly.
[0005]
Therefore, there was no way to know how one's eyes would feel for various colors. In addition, there is a state where color shift of a color reproduction device cannot be performed without a measuring device, and even if there is a measuring device, there are cases where measurement results cannot be understood. Further, the chromaticity and color temperature of the light source could not be accurately grasped by visual perception.
[0006]
Therefore, an object of the present invention is to develop a simple inspection method that can easily and surely determine the way of feeling the color of the eyes, the color characteristics of the light source, and the characteristics of the device color reproduction by visual perception without measuring equipment. And
[0007]
[Means for solving the problem]
Therefore, in the present invention, a representative standard color chart is selected and determined under various light sources, for example, a representative JIS standard color chart piece, and a CMY mixed color system whose chromaticity matches the standard color chart piece under various light sources. A color chart created by subtle color conversion of the three primary color ratios in the color balance adjustment of image processing with respect to the chromaticity centered on the ink color part produced with the ink, and matching the color chart with visual perception and making the color match Based on the already measured chromaticity (xy, ab) of the color part, the difference in the color characteristics of the eye with the CIE standard observer is detected, and the degree and direction of the color shift in the color reproduction of equipment such as a camera and a scanner are visually checked. The above problem is solved by making it possible to detect by feeling.
[0008]
That is, in the present invention, for example, 10 pure colors of 5R, 5YR, 5Y, 5GY, 5G, 5BG, 5B, 5PB, 5P, and 5RP are selected as representative standard color chips, and the chromaticity is determined by the standard light source and the color evaluation. Chromaticity of a practical fluorescent light source such as 5000 ° K, 5,500 ° K, etc. is measured, and a color portion printed with a CMY color mixture in is set at the center so as to match or approximate the chromaticity. In image processing, for example, B (Y) is plotted on the horizontal axis and G (M) or R (C) is plotted on the vertical axis, and the color balance is delicately converted in plus and minus directions to produce a color chart.
[0009]
Since the approximate color is arranged around the center of the color chart, the standard color chart and the color chart are compared with each other. The color difference, in which direction and if any, there is color misregistration, and color reproduction using a color film, digital camera, or scanner (device color reproduction). In a state where the gray reference photographed or captured together with the coloring (gray reference) is correctly gray-balanced, from the position of the chart color portion where the color matches the color reproduction portion of the standard color chart piece visually (or in device judgment). By detecting the chromaticity difference, the direction and the degree of color shift of each device and color material can be detected.
[0010]
[Action]
The color chart used in the present invention has a chromaticity centering on a standard color chart piece and a color that matches or approximates (equivalent to a condition) with a visual sense under a certain light source under an ink color of a chart printed with CMY inks. Is composed of colors that are subtly converted in plus and minus directions. Since both have the same chromaticity, even if they have the same chromaticity, they have different spectral curves. Therefore, if the eye to be viewed and the light source are different, the two are invisible.
[0011]
If the color perception of the observer is the same as that of the standard observer of CIE, the chromaticity values (xy value, ab value) match at a position where the two look the same in the specified light source, and the color (5R in FIG. 1) It can be determined that there is no color shift, that is, the same as the CIE standard observer.
However, if the color matching position under the specified light source is different from that of the CIE, it means that the spectral sensitivity (curve) of the eye is different from that of the standard observer, and the color shift of the eye is different from the chromaticity difference. The direction and degree will be known.
[0012]
When the determination is performed for all 10 colors, the determination results for all colors are obtained. If there is a color shift, the color is determined on the chromaticity diagram similar to the determination result of the color film. It is possible to display a determination result indicating how much color misregistration occurs with respect to.
In addition, the color changes depending on the light source, and since the chromaticity value also differs, the position at which the colors match is also different. Therefore, by changing the light source and determining with a large number of light sources, it is possible to determine and verify the color vision with higher accuracy. Thus, in the present invention, the color characteristics of eyes and light are visually and logically and scientifically diversified. It is possible to catch up.
In addition, in the device color reproduction of a camera, a film, or the like, after capturing and capturing, in print or image processing, the gray standard captured and captured at the same time is correctly adjusted to an achromatic color (ab is 0 in Lab adjustment). The degree and direction of the color shift can be determined from the chromaticity of the color portion similar to the standard color chart on the screen.
[0013]
【Example】
FIG. 1 shows an embodiment of the color chart section of the present invention. FIG. 2 shows a standard color chart piece 12 on the color chart board 1 which is moved up and down so that colorimetry and color matching can be performed. By sliding the slide plate 10 in the up and down direction, the color of each part of the standard color chart piece and the color chart can be compared with the color and color matching.
[0014]
On the color chart plate 1, ten chromatic colors of 5R to 5RP are prepared for each hue. The standard color chart pieces are provided at seven positions for each chart and at twelve positions on the slide plate 10. FIG. 1 shows 5R (red) with chart number 1, and the actual 5R standard color chart is provided on the chart portion 7 and the slide plate 12. The chart section 2 is made by image processing and printing of a personal computer. An ink color having the same chromaticity as that of the standard color chart is provided at a central position 3 at a specified light source. For example, in the Lab mode, the abscissa represents a (indicated by the symbol JKLM) and the ordinate represents b (indicated by numbers 1, 2, 3,...), And the chromaticity of the center color is plus and minus. The direction converted color is brought about by the mixture of CMY inks. Practically, the prescribed light source may be, for example, a B light source or D50.
[0015]
To determine the color misregistration of the eye, the knob 11 of the slide plate is moved up and down on the chart plate under the specified light source to search for a portion that can be seen closest to the standard color chart piece 12 (same as 7). If the color matching position is the center position, since both have the same chromaticity, it is found that they are equal to the standard observer, that is, there is no color shift for the color (5R in this case).
[00016]
In the present invention, the chromaticity of each part of the color chart is measured and displayed in the form of a chart in the same relationship as the color chart. The degree and direction are known.
[0017]
Therefore, if a check is performed on the basic 10 colors from 5R to 5RP, it becomes possible to inspect the color vision characteristics of the human eye, which could not be easily determined until now, in all color directions. Then, depending on the eyes that do not have color misregistration in all colors, if the determination is made based on the achromatic standard color chart and the achromatic chart obtained by converting the ink color having the same chromaticity as the achromatic color, the color at the position of the same color is determined. From the degree, the color characteristics of the illuminating light source can be determined.
[0018]
That is, since the chromaticity of each part of the chart differs depending on the type of the measurement light source, the position of the same color changes when the light source changes. Therefore, by referring to the data of various light sources, if the eye is the same as the standard observer, various charts are used. By using, it is possible to inspect fairly strict color temperature of the light source and color shift in the isochromatic temperature line on the chromaticity diagram without instrument measurement, and determine the error due to instrument measurement It is also possible to do.
[0019]
Next, the procedure for inspecting the characteristics of the device color reproduction according to the present invention will be described. In the case of film, both the negative and the reversal were photographed with the designated light source of the film (the gray reference 9 in FIG. 1 was correctly reproduced). In the state, there is no color shift if the chart portion that looks the same as the 7th and 12th positions of the photographed print or slide is at the center (3 positions), and if it is off the center, the numerical value of the chromaticity table at the shooting color temperature It is possible to judge visually and in what direction and how much the color is displaced by measuring the color without any equipment measurement.
[0020]
In the case of a digital camera as well, if an image is captured and taken into a monitor in the same manner and the achromatic stage of the gray standard 9 is adjusted to a specified L value, and if the printout is determined in the same manner as the above-described film, the image device or It is possible to determine the color characteristics including the printout material.
[0021]
The above description is based on the assumption that the light source determination around 5000k to 5500k is used, and the color portion having the chromaticity that matches the standard color chart piece is located at the center of the chart, but the color is matched by the light source. The positions are different and therefore not always centered.
Also, if the standard value is always at the center, the observer may always select the center, so the chart is randomly moved up and down two steps, three steps, or left and right, and the observer A configuration in which the standard value position is unknown can be adopted.
[0022]
FIG. 3 shows an embodiment in which the present invention is docked with the CIE color calculation software. The hue chart 1 and the slide plate 10 can be freely exchanged at the upper part of the main body 13, activated by the power button 14, While linked, the pen touches the symbol and number at the same color position on the touch panel 15 with the pen, and selects and presses the light source switching button 16. In the chromaticity display section 17, the xy numerical value of the CIE chromaticity of each light source, and This is a color vision judgment device with a calculator configured to calculate and display ab numerical values.
[0023]
The mode switch button 18 provides a function of switching and displaying the isochromatic point position corresponding to the light source color, the position on the xy chromaticity diagram, the position on the ab chromaticity diagram, the color difference, and the like. It is possible to call up the target data with simple operation without any need, and the like, so that quick color vision inspection can be performed.
[0024]
The above is an example of a handy type, but a large panel can be manufactured, and the colorimetric part can provide a standard color chart piece on one side of a mask of the same size, and the color chart part can be taken in the transparent part It is also possible to adopt a structure in which the rectangular mask can be freely moved up, down, left, and right with respect to each color to enable colorimetry.
[0025]
【The invention's effect】
The effect of the present invention is, first of all, whether or not each eye is indeed the same color vision as the CIE standard observer, which has been almost invisible until now and east and west, and if not, which The effect of being able to answer questions about how colors shift in color simply and reliably without visual measurement without instrument measurement is that the color characteristics of each eye can be known for the first time. This makes it possible for the first time to make decisions based on characteristics and to handle colors, which is an epoch-making effect that greatly reforms visual color decisions.
[0026]
In general, it can be said that human vision is considered to be similar or quite different, but it is nothing less than the development of an easy, simple and reliable way to grasp the reality.
[0027]
Until now, the characteristics of each person's eyes, which were almost unknown, became evident for the first time, and as a result, it was known whether they were equal to the standard observer. The color quality can be elucidated in considerable detail, and if the characteristics of the eyes are known, the direction and degree of color misregistration with the standard can be determined, so that color handling that takes that into account is possible, and in any case the characteristics are clear All eyes will be color meters with high accuracy.
[0028]
A method for verifying the measurement results of equipment by making it possible to check the color temperature of the light source, the relationship with the standard light source, the degree of color misregistration in the G direction and the M direction in the isochromatic temperature locus on the chromaticity diagram, etc. And effective data can be provided for solving the problem with the currently occurring visual sensation and the confusion of the color of the device measurement result.
In color practice, visual sensation judgments that have been ambiguous so far can be logically and scientifically verified by the present invention, so it is the first time that the same strict judgment as instrument measurement, or more, can be made, Many previously unknown issues have been elucidated, and more accurate, logical and rational handling and analysis of colors and color matching have been realized, which can significantly improve the quality of color judgment. .
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a color chart plate.
FIG. 2 is an explanatory diagram of a slide plate on a color chart plate for performing colorimetric and color matching with a standard color chart piece.
FIG. 3 is an embodiment of a color vision judgment device with a calculator having a function of color calculation software.
[Explanation of symbols]
1 Color chart board 2 Color chart section printed with CMY inks.
37. Ink color portions that are conditionally matched with the standard color chips of 7 and 12 (5R in the figure) and the specified light source.
4 Vertical axis symbol.
5 Chart hue number.
6 Hue name (5R in the figure).
7 The actual color chart (5R in the figure).
8 Horizontal axis number.
9 Achromatic (gray) standard.
10 Slide plate.
11 Knob for raising and lowering.
12 The actual color chart piece (5R in the figure).
13 One embodiment of the main body of the color vision judgment device with a calculator.
14 Power button.
15 Touch panel 16 Light source selection button.
17 chromaticity display section.
18 Mode switching button.

Claims (1)

In the image processing, the chromaticity is delicate in image processing around a typical JIS standard color chart piece and an ink color portion made of a CMY mixed color ink having the same chromaticity as the standard color chart piece in various light sources. And color matching with a color chart in which the approximate color is arranged, by visual feeling, and referring to the chromaticity (xy, ab) of the chart color portion that matches colors, the color of the eye with the CIE standard observer The color of eyes, light sources, and equipment is characterized by detecting differences in characteristics and capturing and capturing charts to detect the degree and direction of color misregistration in the color reproduction of equipment such as cameras and scanners. Characteristic detection method.

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