JP2000019106A - Method for measuring light transmittance of liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make transmittance of a measured solution easily measurable by inversely computing three stimulus values of complementary color from the complementary color obtained from chromaticity, and multiplying the further computed spectral distribution of the complementary color by spectral distribution outputted from a sensor to electrically obtain the complementary color. SOLUTION: Spectral distribution Tn (λ) of light transmitted through a sample is outputted from a spectral sensor and inputted to a microcomputer, and three stimulus values X, Y, Z obtained by multiplying Tn (λ) by an isochromatic function by a three- stimulus value XYZ computing element 61 of the microcomputer are inputted to a chromaticity computing element 62. A complementary color computing element 63 computes complementary color from the chromaticity of output Cn of the computing element 62, and a chromaticity → spectral distribution computing element 64 inversely computes three stimulus values X, Y, Z of complementary color from the output Cn. Spectral direction (λ) of complementary color obtained by dividing X, Y, Z by an isochromatic function is outputted and inputted to a multiplier 65. The multiplier also inputs the spectral distribution value Tn (λ) from the spectral sensor and obtains transmittance Th (λ) to the complementary color by Tn (λ)×H (λ). A mechanical filter equivalent to the complementary color is therefore dispensed with, and operation for selecting this is also dispensed with.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for measuring light transmittance of a liquid.

[0002]

2. Description of the Related Art At present, various kinds of apparatuses for measuring the degree of coloring of wastewater have been developed in order to determine the regulation standards for industrial wastewater.
For example, according to “Coloring degree measuring method and measuring apparatus” in JP-A-7-43302, light including visible light is projected onto a flow cell through which a sample flows without being separated, and light transmitted through the flow cell is detected. The transmittance or the absorbance is determined, and the degree of coloring of the sample is measured based on the transmittance or the absorbance. According to this method, the degree of coloring of the liquid flowing through the flow cell is measured from time to time, and more accurate measurement is possible as compared with a conventional method in which a stationary sample is visually observed and compared with a standard solution to determine the degree of coloring. is there. Further, according to this publication, in order to enable highly selective measurement of hue, the transmittance of each of yellow, red, and blue wastewater is in a short wavelength region,
It becomes smaller in the middle wavelength region and the longer wavelength region closer to the short wavelength. Therefore, by using a cut filter corresponding to the wavelength characteristic to cut light rays in a region having a large transmittance, measurement can be performed with light in a wavelength region suitable for the hue of each sample. According to this, it is possible to perform highly selective measurement.However, a cut filter of this kind is actually used by a person who looks at the hue flowing through the flow cell at that time and uses a cut filter according to this. However, when the change in the coloring of the liquid flow flowing through the flow cell is large, it cannot be dealt with. Also, accurate hue measurement is difficult.

On the other hand, in Japanese Patent Application Laid-Open No. 9-43140,
Since the degree of coloring determined by the dilution method is obtained from the sum of the absorbances of X, Y, and Z, light rays having the same wavelength as the hue of the liquid to be measured are also included. Therefore, in the low coloring degree region, the transmitted light intensity increases, and the measurement accuracy decreases.

In view of the above-mentioned problems, the present applicant accurately measures the coloring degree of wastewater that changes every moment, such as factory wastewater, at low cost from low-density areas to high-density areas without being affected by hue. With the object of providing a coloring degree measuring device that can perform a white light source, a transparent container filled with a liquid whose coloring degree is to be measured, and a light from the white light source transmitted through the transparent container. A chromaticity conversion filter that transmits light of red (R), green (G), and blue (B) wavelengths, a first photoelectric converter that receives light passing through these filters, and an amplifier that amplifies the detection signal And from the output of the amplifier,
And a calculator for calculating the hue of the liquid, wherein a filter selected from the hue that is the calculation result of the calculator is arranged between the white light source and the second photoelectric converter. In the coloring degree measuring device, a liquid to be measured for coloring degree is allowed to flow through the transparent container, and a plurality of types of filters that preferentially pass light beams of complementary colors of the respective hues are provided. A moving plate having an opening to pass therethrough, and a driving device for moving the moving plate are provided, and at the start of the measurement, the driving device moves the moving plate so that light from the white light source passes through the opening, Next, the driving device is driven by the operation result of the operation unit, and the moving plate is moved so that a filter that preferentially passes complementary color light of a hue corresponding to the operation result is aligned on the optical axis. The light that has passed Is received by the second photoelectric converter, and the degree of coloring of the liquid is measured from the output of the second photoelectric converter. Hei 9-170987).

Hereinafter, the coloring degree measuring apparatus will be described with reference to the drawings.

FIG. 5 shows the whole, in which a white light source 1 is introduced into a collimator 2, where it is converted into a parallel light, and a parallel light is passed through an aperture or an optical filter selected at that time in an optical filter spectral plate 4. Is passed. The light that has passed through the opening is transmitted through a flow cell 5 made of a transparent material, and filters 8a, 9a, and 10 for obtaining tristimulus values.
a and the photoelectric converters 8b, 9b, and 10b.
The liquid whose coloring degree is to be measured flows from above to below in the flow cell 5, and exhibits a certain hue. The respective outputs of the photoelectric converters 8b, 9b, 10b that receive the transmitted light of the filters 8a, 9a, 10a for obtaining the tristimulus values are amplified by the amplifier 12 and supplied to the control operation processing unit 13. In the control operation processing unit 13, the tristimulus value X,
Y and Z are calculated, and the hue of the liquid currently flowing through the flow cell 5 is calculated by a predetermined calculation. A drive output of the pulse motor 14 for driving the spectral plate 4 is generated to select an optical filter corresponding to the calculated hue complementary color. On the other hand, the calculation result is displayed on the display. Alternatively, it is supplied as a print output to a printer.

Next, this operation will be described.

Now, it is assumed that a wastewater having a red hue is flowing through the flow cell 5. The light from the white light source 1 is converted into a parallel light by the collimator 2, and the opening 4 a is set at a position opposing the flow cell 5 in the spectral plate 4 at the start of the measurement. Therefore, no rays are filtered,
Penetrates the liquid to be measured flowing through the flow cell 5;
The transmitted light intensity is detected by the YZ tristimulus value detection filters 8a, 9a, and 10a and the photoelectric converters 8b, 9b, and 10b, and the respective outputs are amplified by the amplifier 12 and supplied to the control operation processing unit 13. The microcomputer calculates a tristimulus value XYZ of the liquid currently flowing through the flow cell 5 in the control calculation processing unit 13 and further calculates a hue from the XYZ value. With this calculation output, the pulse number is now set in the pulse motor 14 to select blue-green, which is a complementary color of red,
The spectral plate 4 is rotated. Accordingly, the filter that transmits blue and green and is fitted in the opening 4b is stopped facing the flow cell 5.

The light from the white light source 1 is converted into a parallel light by the collimator 2, passes through the liquid flowing through the flow cell 5, and then becomes the XYZ detection filters 8a, 9a, 1a.
Oa is not transmitted, and the photoelectric converter 12 receives the light of the complementary color, and the output is amplified by the amplifier 12, and the transmittance and the absorbance of the complementary color light of the hue of the liquid are obtained. A plurality of kinds of calibration curves of absorbance and coloring degree by the dilution method are prepared in advance using complementary color light of the hue of the liquid, and the ROM (R
In this case, one of these calibration curves is selected by determining the hue of the sample, and the degree of coloring of the liquid currently flowing through the flow cell 5 is accurately calculated from the absorbance measured with the complementary light. Can be. In the case of a liquid having a red hue flowing through the flow cell 5, a blue-green light beam, which is a complementary color of red, absorbs a large amount of light passing through the sample, and a high degree of coloring is required even in a low concentration region. Can be The above description is for the case where the hue of the liquid flowing through the flow cell 5 is red.
Z detection filters 8a, 9a, 10a and photoelectric converter 8
The control processor 13 calculates the blue of this hue based on the outputs of b, 9b, and 10b, sets the number of pulses of the pulse motor 14 based on the calculation result, and rotates the spectral plate 4 to select the complementary light of blue. Then, the filter 23 transmitting yellow, which is a complementary color of blue, which is fitted in the opening 4 </ b> C is stopped facing the flow cell 5. Hereinafter, the degree of coloring is determined in the same manner as in the case where the hue is red.

However, in the above apparatus, after calculating the complementary color by a computer, a filter having the hue of the complementary color is selected by rotating the disk 4 to measure the degree of coloring of the sample. Therefore, filters must be prepared by the number of colors corresponding to the complementary colors.
This positioning is also troublesome.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a computer that calculates a complementary color of a measurement solution, does not require any mechanical filter, and has a drive mechanism for selecting the color. It is another object of the present invention to provide a method for measuring the light transmittance of a liquid, which can measure the degree of coloring, that is, the transmittance of a measurement solution.

[0012]

An object of the present invention is to transmit a light beam from a white light source to a transparent container filled with a liquid whose transmittance is to be measured, and to receive the transmitted light by a spectral sensor. From the output, calculate tristimulus values X, Y, and Z from the output, and calculate the chromaticity from the calculation result. The complementary color is calculated, the tristimulus value of the complementary color is inversely calculated from the complementary color, the spectral distribution of the complementary color is calculated based on the inverse calculation, and the calculation result is multiplied by the spectral distribution which is the output of the spectral sensor. Accordingly, a liquid light transmittance measuring method is characterized in that the liquid transmittance is measured.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the whole of a liquid light transmittance measuring apparatus according to an embodiment of the present invention. Description is omitted.

That is, according to the present embodiment, the spectroscopic sensor 50 is used, which is a plurality of sensors arranged for each wavelength, and the output Tn (λ) is supplied to the microcomputer 51. . Here, λ represents a wavelength, and Tn (λ) represents the transmittance of light of this wavelength. That is, the output of the spectroscopic sensor 50 outputs the spectral distribution of the light beam that has passed through the sample at this time. This is the tristimulus value XYZ calculator 61 in the microcomputer 51 in FIG.
Supplied to As known, a tristimulus value XYZ is obtained by multiplying this spectral distribution by a color-matching function representing spectral sensitivity corresponding to the human eye. The calculation result XYZ is supplied to a chromaticity calculator 62. You.

According to the present embodiment, XYZ (Yxy)
A color system chromaticity diagram is used. As shown in FIG. 3, the chromaticity can be represented by the values of x and y. The relationship between these x and y and the lightness z which is the value in the vertical direction is x = X / (X + Y + Z), y =
Y / (X + Y + Z), z = Z / (X + Y + Z) = 1-x
-Y, x, y, and z are determined by the above equations. That is, in the chromaticity diagram of FIG. 3, according to the hue of the solution at this time, the coordinate points p ₁ is determined.

The output Cn of the chromaticity calculator 62 is a complementary color calculator 6
3 is supplied. Within this calculator 63, shows the point W is the white point in FIG. 3 (x = y = 1/ 3), if the coordinate point representing the chromaticity of the measurement solution with p _1, p ₁ and W And the point p ₂ on the extended line is a complementary color (on both sides of the point W). This complementary color p ₂ is supplied to the chromaticity → spectral distribution calculator 64 as the output Cn. The complementary color is xy
Although represented by the z value, X, Y, and Z are back calculated from the above relational expression. As a result, the tristimulus value XYZ of this complementary color is obtained. By further dividing this by the color matching function shown in FIG. 4, the spectral distribution of this complementary color is obtained. This output H (λ) is supplied to the multiplier 65.

On the other hand, the result of spectroscopy of the measurement solution by the spectroscopic sensor 50, that is, the value of the spectral distribution Tn (λ) is supplied to the multiplier 65, and the transmittance Th for the complementary color is calculated by Tn (λ) × Hh (λ). (Λ) is obtained. As described in the above-mentioned conventional example, the transmittance can be measured with high sensitivity even at a low density for a complementary color. However, according to the embodiment of the present invention, a mechanical filter equivalent to the complementary color is used. Nothing is needed. Therefore, there is no need for an operation for selecting this.

Although the embodiment of the present invention has been described above, the present invention is, of course, not limited to this, and various modifications can be made based on the technical idea of the present invention.

For example, in the above-described embodiment, the spectroscopic sensor 50 is a plurality of sensors arranged for each wavelength as shown in the figure. However, the present invention is not limited to this, and x (λ) representing red, green, and blue filters is used. ) Sensors, y (λ) sensors and z (λ) sensors may be used. In the figure, underlines of x, y, and z are described above these characters as usual.

In the above embodiment, the complementary color calculator 6
3, the white point W from the CIExyz color system chromaticity diagram
It is assumed that the point p ₂ is on both sides of the image. However, it is needless to say that the present invention is not limited to this.

[0021]

As described above, according to the method for measuring the light transmittance of a liquid according to the present invention, it is possible to obtain a complementary color electrically and to obtain high sensitivity.
The coloring degree, ie, the transmittance, of the measurement solution can be easily obtained by a simple operation.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus for measuring the permeability of a solution according to an embodiment of the present invention.

FIG. 2 is a circuit block diagram in the microcomputer in FIG.

FIG. 3 shows XY set in the microcomputer.
It is a chart of a Z color system chromaticity diagram.

FIG. 4 is a chart showing a color matching function.

FIG. 5 is a schematic front view of a conventional color measuring device.

FIG. 6 is a front view of a main part of the device.

[Explanation of symbols]

 Reference Signs List 50 spectral sensor 51 microcomputer 61 tristimulus value XYZ calculator 62 chromaticity calculator 63 complementary color calculator 64 chromaticity → spectral distribution calculator 65 multiplier

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2G020 AA08 BA02 BA14 CA02 CB43 CC26 CD04 CD13 CD22 CD51 DA02 DA13 DA23 DA32 DA35 DA62 2G059 AA02 AA05 BB04 CC19 EE01 EE13 FF01 HH02 JJ01 JJ21 KK01 MM01 MM09 NN06NN06NN

Claims (4)

[Claims] 1. A light beam from a white light source is transmitted through a transparent container filled with a liquid whose transmittance is to be measured, the transmitted light is received by a spectral sensor, and a spectral distribution is output from the spectral sensor. Calculating the tristimulus values X, Y, and Z from the above, and calculating the chromaticity from the calculation result. In the liquid light transmittance measuring method, a complementary color of the chromaticity is calculated from the chromaticity, and the complementary color is calculated. From the tristimulus value of the complementary color, calculate the spectral distribution of the complementary color based on the inverse calculation, and measure the transmittance of the liquid by multiplying the calculation result by the spectral distribution which is the output of the spectral sensor. A method for measuring the light transmittance of a liquid, comprising: 2. The method according to claim 1, wherein the spectral distribution of the complementary color is obtained by dividing the tristimulus value by a color matching function. 3. The method for measuring light transmittance of a liquid according to claim 1, wherein the complementary color is obtained from an XYZ color system chromaticity diagram. 4. The spectroscopic sensor according to claim 1,x(Λ) sensor,y
(Λ) sensor andz(Λ) sensor
The light transmittance measurement of the liquid according to claim 1.
Method.