CN104122213A - Method for measuring chromaticity of water quality - Google Patents

Abstract

The invention discloses a method for measuring the chromaticity of water quality. A measurement system comprises a halogen lamp, a water sample pool and a fiber optic spectrometer; the chromaticity of water quality can be measured by a hue-saturation-value (HSV) color model. The water transmission spectra measured by the spectrometer is used for calculating XYZ tristimulus values of water transmission light color, an XYZ chromaticity system can be converted into an HSV chromaticity system by the colorimetry principle, and the chromaticity of water can be obtained by carrying out conversion according to the S. The method is capable of measuring the hues (H) of water at the same time, so that the water with different hues can be measured. The value (V) in the HSV chromaticity system is an independent component, so that the saturation and the hues which are calculated by the method are not easily influenced by the instability of the values (V) of a light source. The method has the characteristics of being objective in determination and suitable for measuring the water with different colors, and being not easily influenced by light intensity change.

Description

A kind of method of measuring water quality colourity

Technical field

The present invention relates to water quality monitoring field, be specifically related to a kind of method that the HSV of utilization colorimeter system is measured water quality chromatic value.

Background technology

Pollution can cause the change of water body color, especially weaves, the pollution of the industry such as printing and dyeing, process hides, papermaking, pharmacy, food.Therefore, monitoring water pollution situation can be started with from measuring the colourity of water, the index using colourity as monitoring water quality.

The acquisition methods of existing water body chroma is mainly according to mensuration GB 11903-89 > > of GB < < water quality colourity, to measure the colourity of water body: " platinum cobalt colourimetry " and " extension rate method ", these two kinds of methods are by the subjective comparison of human eye, to judge the colourity of water, do not there is objectivity, and " platinum cobalt colourimetry " is only applicable to judge the colourity of yellow hue water body, do not have versatility.For solving the problem of objective measurement colourity, researcher proposes to utilize spectrophotometer measurement water body absorbance, sets up absorbance that characteristic wavelength is corresponding and the numerical relation between colourity, thereby measures water body chroma value.Yet color depend on water body to incident light the overall absorption situation in 380nm～780nm limit of visible spectrum, if be reduced to by the absorbance of a certain characteristic wavelength, characterize, can produce the problem of metamerism.For addressing this problem, researcher utilizes the absorbance of visible light wave range to calculate the tristimulus values of water body color, choose CIE XYZ and CIE L*a*b* colorimeter system quantitatively characterizing color in colorimetry, set up respectively chromatic value in value of chromatism and " platinum cobalt colourimetry " and the funtcional relationship between the extension rate in " extension rate method ", realize the quantitative measurment of water body chroma, and be extended in the measurement of different tone water bodys.Though the CIE XYZ that the method proposes and CIE L*a*b* colorimeter system energy and chromatic value, extension rate are set up good numerical relation, and human eye visual perception is face three attributes of color (colourity, saturation degree and brightness), so the method is directly perceived not to the sign of color and colourity.

Summary of the invention

The present invention is directed to the problem that is subject to subjective factor impact that current water quality colour measurement method exists, only with single features wavelength, calculate colourity and easily produce the problem that the problem of metamerism and the colorimeter system of employing cannot intuitively characterize human eye impression, a kind of method to water quality colourity sign objectivity and the strong measurement water quality chromatic value of intuitive is provided.

The technical scheme of measurement water quality chromatic value method provided by the invention comprises the following steps:

Step 1: tested water body is inserted to sample cell, with Halogen lamp LED optical fiber source, water body example pond and fiber spectrometer, form transmission-type measuring system, Halogen lamp LED emits beam after coupled into optical fibres and is incident to water body example pond, light transmits that water body sample to be measured is laggard enters fiber spectrometer, and spectrometer records the transmittance spectra data S (λ) of tested water body;

Step 2: by formula

Calculate the XYZ tristimulus values of the color of water body; Wherein , , for " CIE1931 standard colorimetric observer spectral tristimulus value ";

Step 3: by formula

The XYZ colorimeter system of the tested water body obtaining is converted to RGB colorimeter system;

Step 4: by formula

Be converted to HSV colorimeter system, wherein, V is brightness; S is saturation degree, and variation range is 0～1; H is tone, and span is 0～2 л;

Step 5: by formula

, obtaining tested water body tone is the water quality chromatic value C of H.

Compared with prior art, the advantage of technical scheme of the present invention is:

1, the spectroscopic data that chroma data provided by the present invention is recorded by spectrometer calculates, for objective quantitative, measure, solved " platinum cobalt colourimetry " and " extension rate method " in mensuration GB 11903-89 > > of GB < < water quality colourity and be subject to the problem that subjective factor affects.

2, the present invention adopts HSV colorimeter system to water body transmitted light characterization, with respect to other technologies scheme, HSV is a kind of colorimeter system intuitively, matching with Human Perception feature, and the chromatic value C of intensity value S and standard colorimetric water body has good linear relationship, therefore, can directly according to intensity value, calculate water quality chromatic value.

3, the present invention adopts spectroscopic data to calculate the method for HSV tristimulus values, comprising tone value H, can be used for measuring the water body of different tones, solved that in mensuration GB 11903-89 > > of GB < < water quality colourity, " platinum cobalt colourimetry " only can be for measuring the problem of yellow hue water body.

4, the present invention adopts spectroscopic data to calculate the method for HSV tristimulus values, wherein brightness is the independent component that is independent of tone H and saturation degree S, therefore, the unstable calculating that can not affect chromatic value of light source and ambient brightness during measurement, there is anti-interference, improved stability, reliability and the accuracy measured.

Accompanying drawing explanation

The light path schematic diagram for transmission measurement water quality colourity that Fig. 1 provides for the embodiment of the present invention;

Fig. 2 is tone-saturation degree coordinate system schematic diagram that the embodiment of the present invention relates to;

The standard solution chromatic value that Fig. 3 provides for the embodiment of the present invention and the graph of relation of intensity value;

The standard solution chromatic value that Fig. 4 provides for the embodiment of the present invention and the graph of relation of water body tone value;

Fig. 5 be in the embodiment of the present invention, relate in H-S color coordinates system, represent the intensity value schematic diagram of standard colorimetric solution;

In figure, 1, Halogen lamp LED optical fiber source; 2, water body example pond; 3, fiber spectrometer.

Embodiment

Below in conjunction with drawings and Examples, technical solution of the present invention is further elaborated.

Embodiment 1

The present embodiment utilizes HSV colorimeter system that a kind of method of measuring water quality chromatic value is provided.

Referring to accompanying drawing 1, the light path schematic diagram for transmission measurement water quality colourity that it provides for the present embodiment, use halogen tungsten lamp optical fiber source 1, light enters water body example pond 2 after collimation, through tested water body, absorb, transmitted light is accepted by fiber spectrometer 3, obtains transmittance spectra data S (λ), the spectroscopic data S (λ) that utilization records, can calculate the XYZ tristimulus values of the color of water body according to formula (1):

Wherein, , , be respectively " CIE1931 standard colorimetric observer spectral tristimulus value ".By XYZ colorimeter system, be transformed into HSV colorimeter system and can first by formula (2), be transformed into RGB colorimeter system:

（2）

By formula (3), be transformed into HSV system again:

（3）。

In HSV colorimeter system, HSV (Hue tone, Saturation saturation degree, Value brightness) colorimeter system represents with Munsell three-dimensional coordinate system system, it is a kind of colorimeter system intuitively, matching with Human Perception feature, wherein tone H represents by angle, variation range 0～2 л; The distance that saturation degree S leaves center line by radial direction represents, variation range 0～1, and decentering line saturation degree far away is higher; Brightness V is represented by Z-axis, and variation range 0～1 is worth larger brightness higher.HSV colorimeter system is used the brightness of independent V representation in components image, therefore, adopts this colorimeter system to analyze white light interference color image, can avoid the impact of light intensity on interference color tone value H.In the situation that testing light source is basicly stable, brightness value can be considered as to constant, only by color harmony saturation degree, represent color, and foundation tone-saturation degree coordinate system as shown in Figure 2, for evaluate color, horizontal ordinate is tone value, for unified coordinate values, by the variation range of tone, from 0～2 л, through normalization conversion process, is 0～1; Ordinate is saturation degree, variation range 0～1.This coordinate system has advantages of following several respects:

1, utilize two component evaluate color in plane coordinate system, range of value is expanded to all tones, solved " platinum cobalt colourimetry " and can only evaluate the problem of yellow water transfer, and intensity value is corresponding with the chromatic value in " platinum cobalt colourimetry ", solved the problem that objective quantitative is measured water quality colourity;

2, in coordinate system, color harmony intensity value and human eye match to the perception of color;

3, in coordinate system, color harmony saturation degree is linear increment, compares with x-y chromaticity diagram, more directly perceived to the demonstration of the color harmony saturation value of color and differentiation.

Mensuration GB 11903-89 > > preparations 5 according to GB < < water quality colourity, 10, 20, 30, 40, 50, 60, 70, the standard colorimetric solution of 80 degree, use Haiyang optics HL-2000 halogen tungsten lamp light source lighting criteria colourity solution, use Haiyang optics QE65000 spectrometer to gather reflectance spectrum, and calculate the tone value H in HSV colorimeter system according to spectroscopic data, intensity value S and brightness value V, referring to accompanying drawing 3, it is the graph of relation of standard solution chromatic value and intensity value, known chromatic value and intensity value have the numerical relation of approximately linear, do that to obtain closing after fitting a straight line be formula (4) between the two:

（4）

Therefore, the intensity value in available HSV colorimeter system is quantitatively calculated the chromatic value in mensuration GB 11903-89 > > of GB < < water quality colourity.

Referring to accompanying drawing 4, the standard solution chromatic value that it provides for the present embodiment and the graph of relation of water body tone value, as shown in Figure 4, standard solution tone value under different colourity changes very little (being not more than 0.0011), and this and standard solution are that yellow hue water is identical.

If measure other tone water bodys, can utilize H-S color coordinates system to show, horizontal ordinate is tone, for distinguishing the difference of water body shade of color, ordinate is intensity value, can be calculated by above formula with chromatic value.Referring to accompanying drawing 5, it be in the present embodiment, relate in H-S color coordinates system, represent the intensity value schematic diagram of standard colorimetric solution, in Fig. 5, the color harmony saturation degree of standard solution is illustrated in intuitively in H-S color coordinates system, in figure, tone is stabilized in yellow hue region, conforms to actual conditions.

According to the principle of the invention, use HSV colorimeter system to represent water body color, the color harmony intensity value that has intuitively shown water body color, the feature that meets Human Perception color, can convert and obtain water quality chromatic value according to intensity value again simultaneously, realize all tone water bodys are made to objective chromaticity evaluation.

Claims (1)

1. measure a method for water quality colourity, it is characterized in that comprising the following steps:

Step 1: tested water body is inserted to sample cell, with Halogen lamp LED optical fiber source, water body example pond and fiber spectrometer, form transmission-type measuring system, Halogen lamp LED emits beam after coupled into optical fibres and is incident to water body example pond, light transmits that water body sample to be measured is laggard enters fiber spectrometer, and spectrometer records the transmittance spectra data S (λ) of tested water body;

Step 2: by formula

Calculate the XYZ tristimulus values of the color of water body; Wherein , , for " CIE1931 standard colorimetric observer spectral tristimulus value ";

Step 3: by formula

The XYZ colorimeter system of the tested water body obtaining is converted to RGB colorimeter system;

Step 4: by formula

Be converted to HSV colorimeter system, wherein, V is brightness; S is saturation degree, and variation range is 0～1; H is tone, and span is 0～2 л;

Step 5: by formula

, obtaining tested water body tone is the water quality chromatic value C of H.