JPH02232532A - Photoelectric colorimeter - Google Patents

Abstract

PURPOSE:To make it possible to cope with the change in lighting sources when the colors of bodies are measured and the change in a color display method broadly and readily by providing optoelectronic transducer circuits, an operation control part, a memory part and a fuzzy inference means. CONSTITUTION:Optoelectronic transducer circuit 31 - 33 decompose the light from a body to be measured into basic color components and perform optoelectronic transducing operation of the light of each basic color component. An operation control part 8 computes the temporary chromaticity values from the A/D-converted values of sample/hold circuits 41 - 43. In a memory part 7, membership functions, which are formed based on a plurality of limited corresponding chromaticity values under a plurality of limited lighting sources or data with regard to the change in said values and used for fuzzy inference, are stored beforehand. A fuzzy inference means 9 performs fuzzy inference from the temporary chromaticity values computed in the arithmetic control part 8 and the membership functions stored in the memory 7 and computes the chromaticity to be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rechargeable colorimeter for measuring chromaticity in a video recording device such as a colorimeter, a video camera, or an electronic still video camera.

[Prior Art] Conventionally, when performing chromaticity measurement, the measurement must be performed under a certain illumination light source, or when multiple illumination light sources are used, the measurement must be performed under a certain illumination light source. Since the measurement light is separated into monochromatic light, it is large-scale and complicated, and even when correcting the calculated values of a device to be measured under a certain illumination light source, it is possible to use a widely accurate method with simple calculations. For these reasons, it has been difficult to measure things commonly found outdoors or indoors without using a special illumination light source.

In addition, the obtained chromaticity values can be expressed using another calculation formula (XY
When converting to Z system, rgb system, etc.) or compressing the chromaticity value area using a video camera, the calculation formula becomes complicated, and there are problems such as insufficient accuracy when performing it simply. There was an inconvenience.

[Problems to be Solved by the Invention] The present invention has been made to solve the above-mentioned problem that it is not possible to widely and easily respond to changes in the illumination light source and changes in the color display method during object colorimetry. It is an object of the present invention to provide a photoelectric colorimeter that can widely and easily respond to changes in the illumination light source when coloring an object and to design a color display method.

[Means for Solving the Problems] The photoelectric colorimeter of the present invention includes a photoelectric conversion means for color enrichment that decomposes the light from the light source into basic color components and photoelectrically converts the light of the basic color components; A calculation means that calculates a provisional chromaticity value based on a certain calculation method based on the output of the photoelectric conversion means, assuming that it is under a certain light source, and a calculation means that calculates a provisional chromaticity value based on a certain calculation method based on the output of the photoelectric conversion means. a first storage means for storing information regarding a corresponding chromaticity value or a change thereof; a second storage means for storing a membership function used for fuzzy inference; a provisional chromaticity value calculated by the calculation means; fuzzy inference means for calculating the desired chromaticity by performing fuzzy inference based on the information stored in the first storage means and the membership function stored in the second storage means. There is.

[Operation] The temporary chromaticity calculated by the calculating means is converted into the desired chromaticity. In this case, the degree to which the converted value matches the point of the known temporary chromaticity value is stored in the second storage means. Since it is a membership value stored in , and fuzzy inference is performed based on it, conversion can be easily performed for any color with a small amount of stored information, regardless of the state of conversion. In addition, when converting a temporary chromaticity value due to a change in the illumination light source, the extent to which it fits under a known illumination light source is added as a member value to the antecedent part of fuzzy inference. By converting the above temporary chromaticity values, it is possible to easily convert any color under any illumination light/source.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

? In FIG. 1, % 1 l+ 1 2.1 3 is an optical filter, and 21, 22.23 are light receiving elements. The combination of the optical filter 11 and the light-receiving element 2l has a spectral sensitivity of the spectral stimulus value X, and the combination of the optical filter 12 and the light-receiving element 22, and the combination of the optical filter 13 and the light-receiving element 23 have the spectral sensitivity, respectively. It has a spectral sensitivity of stimulus value Y+Z. Here, the spectral sensitivities of X, y, and z are as shown in FIG.

3, , 32, 33 are photoelectric conversion circuits, 4I, 4■, 4, are sample and hold circuits that sample and hold the respective outputs of the photoelectric conversion circuits 31, 32, 33, 5+ +
52+53 are sample and hold circuits 4, . 42.4
3 is a selection switch for selecting the output; 6 is an A/D converter;
7 is a recording section in which membership functions etc. are stored;
Reference numeral 8 denotes an arithmetic control section for calculating chromaticity values, 9 a fuzzy inference means for executing fuzzy inference, and 10 a display section for displaying the calculated chromaticity values.

Is Fig. 3 a cross section of the charging colorimeter in this example? This shows that. That is, 11 is an objective lens, 12 is a half mirror, 13 is an eyepiece lens, 14 is a photoelectric conversion element for color measurement (light receiving elements 2., 22.23 in Fig. 1), and 15 is a chromaticity value display section (first In the figure, the display section 10), 16 is a color measurement switch, and 17 is an illumination light source color switch.

Next, the operation of this embodiment in such a configuration will be explained. The light from the object to be measured passes through the objective lens 11 , a part of it passes through the half mirror 12 , and reaches the eyepiece lens 13 . The measurer can know the range being measured through the eyepiece lens 13.

Further, a part of the light passing through the objective lens 11 is reflected by the half mirror 12 and reaches the photoelectric conversion element 14 for colorimetry. That is, the light from the object to be measured passes through the optical filter 11.
, 12.13, and the light receiving element 21. 22, 23, is photoelectrically converted by photoelectric conversion circuits 3, 3■, 3, and sample-and-hold circuits 41, 42 . Sample and hold is carried out at 43, selection switch 5H, 52 r 53
are turned on sequentially? By this, the sample hold circuit 4,
, 42.4, the values sampled and held are sequentially A/D
The conversion section 6 performs A/D conversion, and the output is sent to the arithmetic control section 8.

In the performance section 8, temporary chromaticity is calculated as x, y, and z values based on the A/D converted values from the sample and hold circuits 41, 4, and 43. The provisional chromaticity in this example is x-! when measuring the color of equal energy white.
/3. y - 1/3, z - f/3, and is the same method used to embellish the light source color.

The temporary chromaticity value calculated by the arithmetic control section 8 is sent to the fuzzy inference means 9, and at the same time, the membership function stored in the storage section 7 is also sent to the fuzzy inference means 9. moreover,
The colorimetric values of the illumination light source, which were measured by a method described later and stored in the storage section 7, are also sent to the fuzzy inference means 9. The fuzzy inference means 9 performs fuzzy inference based on each piece of information supplied, and calculates the desired chromaticity. The chromaticity value calculated here is sent to the calculation control section 8, and further sent from there to the display section 10 for display.

In this example, it is necessary to measure the color of the illumination light source before starting the measurement, but the method is to The color measurement is performed by pressing the illumination light source MI color switch 17, and the color measurement value is stored in the storage section 7.

Further, the actual color measurement operation is performed by pressing the color measurement switch 16.

Next, fuzzy inference in this embodiment will be explained in detail. Figure 4 shows the actually measured color temperature of 3200K.
The provisional chromaticity value under light bulb light and the standard D chromaticity value of the same object
An example of chromaticity values accurately measured using an I-color device is shown. 41~
47 and 41' to 47' are provisional chromaticity values of the same object under the above-mentioned lamp light, and chromaticity values measured with a standard color embellishing device, respectively.

Conversion of these values from 41 to 47.41' to 47' is complicated. However, it is known that if the temporary chromaticity values are close, the conversion result will also be a close value. In other words, 4
A chromaticity point near 1 may be converted to a chromaticity point near 41'.

In this example, the tentative chromaticity values measured were 41 to 4.
I decided to use a membership function to express how close each of 7 is. In addition, the X value before and after conversion,
We decided to use the ratio of y values as a parameter for conversion.

In addition, in this example, we will use the actual DI L value for the 3 Fft illumination light source, and an example of this will be
As shown in the figure. In Fig. 5, 51 is the chromaticity value due to daylight;
Reference numeral 52 indicates a chromaticity value due to fluorescent lamp light, and 53 indicates a chromaticity value due to bulb light. It is also known that the closer the chromaticity values of the illumination light sources are, the more similar the conversion will be. It was decided to express how close the measured chromaticity of the above-mentioned 71FJ illumination light source is to each of 51 to 53 using a membership function.

FIG. 6 shows an example of membership functions used for fuzzy inference in this embodiment. There are a total of 21 rules, each with four outputs for the antecedent part and two outputs for the consequent part. R1 to R7 show the rules when the illumination light source is bulb light, R8 to R14 the illumination light source is fluorescent light, and R15 to R21 show the rules when the illumination light source is daylight. Two of the four manual inputs in the antecedent part indicate which light source the chromaticity The x and y values indicate which tentative chromaticity value the chromaticity value is close to. The two outputs of the consequent part are magnifications indicating how many times the temporary chromaticity values X and Y should be multiplied. By combining these four outputs of the antecedent part and the two outputs of the consequent part to the maximum value and minimum value for each rule, and finding the center of gravity of the output values of all the rules, we can create the tentative result of the above AJ1 color. Infer a number to multiply by a chromaticity value. Then, this is multiplied by a provisional chromaticity value in the arithmetic control unit 8 to calculate the desired chromaticity.

In this example, even if the illumination light source is arbitrary or the color of the object to be measured is arbitrary, the chromaticity to be determined is estimated in advance from the illumination light source and chromaticity value taken up when creating the above rules. - Not only is it possible to calculate, but the number of memories is also small compared to the method of storing all expected illumination light sources and chromaticity points, and calculations can be made easily without using complicated calculation formulas. Therefore, it can be used for small photoelectric colorimeters and video cameras without having to choose the measurement location or illumination source. It is applicable.

In addition, in this embodiment, if the number of rules is increased by increasing the types of illumination light sources and temporary chromaticity values that are predetermined by 71lI, the accuracy will be further improved.

Further, as the parameters used in the antecedent part of the fuzzy inference, other color systems such as RGB system, Luv system, Lab system, etc. may be used, or it is also possible to use color difference.

Further, as for the value used in the consequent part, it is also possible to use a chromaticity value after conversion, a difference between chromaticity values before and after conversion, or the like.

Moreover, it is also possible to use a prism, a diffraction grating, and a light receiving element instead of the three optical filters and three light receiving elements, and it is possible to use any color sensor.

Further, regarding the Mj color of the illumination light source, a separate color sensor, color temperature sensor, etc. may be installed on the device to automatically perform the determination at all times.

Further, as for the fuzzy inference method, a method other than maximum value-minimum value combination may be used, and a method other than the centroid method may be used for rule combination. Further, fuzzy inference can also be performed by the arithmetic control section.

Furthermore, the membership function may be a trapezoid other than a triangle, and the consequent may be a value with no width.

Next, other embodiments of the present invention will be described.

For example, when it is necessary to record or reproduce color images from a video camera or the like, it may be necessary to compressively narrow the chromaticity range to be recorded or reproduced. An example will be explained using FIG. 7. Figure 7 is a chromaticity diagram based on the XYZ system, where 71 indicates the boundaries of the actual color range, and 72 indicates the NTS
The color reproducible area of a color CRT according to the C method is shown.

Further, 73 to 76.73' to 76' indicate the chromaticity points before and after conversion in this embodiment.

As seen in FIG. 7, there are limits to the colors that can be reproduced on a color CRT. At this time, in order to reproduce more colors in a richer manner, the problem is how to convert and reproduce the actual chromaticity. In this example, the chromaticity before and after conversion of some of these chromaticity points, for example, points located on the outer side of the chromaticity diagram, or chromaticity points that are sensitive and important to human visual sense, are calculated. Based on that point, fE
By using the degree of proximity of the desired chromaticity point to the determined chromaticity point of the chromaticity change as a membership function, the measurement or photographing was performed using the same fuzzy reasoning as in the above embodiment. It is possible to perform chromaticity conversion so that chromaticity can be naturally and easily reproduced.

Note that this embodiment is applicable not only to video cameras but also to color copies and other video recording/reproduction devices that require chromaticity conversion for reproduction range or other reasons.

In addition to the above embodiments, for example, RGB system and XYZ
Regarding the transformation between different chromaticity coordinate systems such as It can be converted to a color system.

[Effects of the Invention] As detailed above, according to the present invention, the illumination light source and color display method are not limited as in the past, and it is possible to adapt to changes in the illumination light source and color display method during object colorimetry. It is possible to provide a photoelectric colorimeter that can be applied to a wide range of products.

[Brief explanation of the drawing]

1 to 6 are for explaining one embodiment of the present invention, in which FIG. 1 is a block diagram showing the configuration of a photoelectric colorimeter, FIG. 2 is a spectral sensitivity characteristic diagram of the photoelectric conversion means, and FIG. Figure 3 is a cross-sectional view of the photoelectric colorimeter, Figure 4 is a diagram showing an example of the provisional chromaticity value under light bulb light obtained with actual 11!1L and the chromaticity value after n1 color, and Figure 5 is a diagram showing an example of the chromaticity value obtained by n1 color. Figure 6 is a diagram showing an example of the chromaticity values actually measured for a 38i illumination light source, Figure 6 is a diagram showing an example of membership functions used in fuzzy inference, and Figure 7 is a diagram showing colors for explaining another embodiment of the present invention. It is a degree diagram. II, 12+ 13... Optical filter, 2 1 +
2 2 +23... Light receiving element, 31, 32.33
... Photoelectric conversion circuit, 41, 42. 43 ... Sample hold circuit, 6 ... A/D conversion section, 7 ... Storage section, 8 ... Arithmetic control section, 9 ... Fuzzy inference means.

Claims (2)

[Claims] (1) A photoelectric conversion means for colorimetry that separates the light from the object to be measured into basic color components and photoelectrically converts the light of the basic color components; a calculation means for calculating a provisional chromaticity value based on a certain calculation method; and a first storage means for storing in advance information regarding a plurality of finite corresponding chromaticity values or changes thereof under a plurality of finite illumination light sources. and a second memory that stores the membership functions used for fuzzy inference.
fuzzy inference based on the temporary chromaticity value calculated by the calculation means, the information stored in the first storage means, and the membership function stored in the second storage means. A photoelectric colorimeter comprising fuzzy inference means for calculating the desired chromaticity by performing the following steps. (2) A photoelectric conversion means for colorimetry that separates the light from the object to be measured into basic color components and photoelectrically converts the light of the basic color components; A calculation means for calculating a provisional chromaticity value based on a certain calculation method; and a first storage means for storing in advance information regarding a plurality of finite corresponding chromaticity values or changes thereof in a plurality of finite color display methods. and a second memory that stores the membership functions used for fuzzy inference.
fuzzy inference based on the temporary chromaticity value calculated by the calculation means, the information stored in the first storage means, and the membership function stored in the second storage means. A photoelectric colorimeter comprising fuzzy inference means for calculating the desired chromaticity by performing the following steps.