A water quality detection method and device for environmental protection detection

Abstract

This application relates to the technical field of water quality detection, and specifically relates to a water quality detection method and device for environmental protection detection. The method includes: respectively obtaining the ultraviolet absorption spectra of the water quality to be measured and the standard COD solution, extracting each modal component to be analyzed and each standard modal component, constructing a variation coefficient of the peak position difference between the modal component to be analyzed and the standard modal component, thereby obtaining the turbidity interference factor of the modal component to be analyzed, and determining the peak difference consistency of the modal vector to be analyzed; based on this, calculating the superimposed interference eigenvalue of each modal vector to be analyzed, extracting the COD absorbance component vector in the ultraviolet absorption spectrum to be measured, and obtaining the ultraviolet absorption spectrum after turbidity interference elimination through wavelet fusion; measuring the COD concentration in the water quality to be measured by using Lambert-Beer's law. This application improves the detection accuracy of the COD content in the water body of environmental protection water quality and improves the accuracy of environmental protection water quality detection.

Description

Technical Field

[0001] This application relates to the technical field of water quality detection, and particularly relates to a water quality detection method and device for environmental protection detection. Background Art

[0002] The traditional water quality detection method is the chemical method, which has the characteristics of high water quality detection accuracy. However, it requires a large amount of time cost and is prone to secondary pollution during the process of detecting water quality by the chemical method, and cannot meet the environmental protection requirements of environmental protection detection. With the continuous development of spectral feature analysis technology, by using the absorption spectrum or transmission spectrum of pollutants in water quality to the spectrum, the degree of water quality pollution in water can be effectively identified and measured. At the same time, the method of detecting water quality pollutants through spectral feature analysis has the advantages of rapidity, no pollution and low cost, and has a wide range of applications in environmental protection detection.

[0003] The prior art uses an ultraviolet-visible spectrophotometer to measure the ultraviolet absorption spectrum of water bodies in water quality, analyzes the absorption peak characteristics of the COD concentration in the ultraviolet absorption spectrum through spectral feature analysis technology, and calculates the COD concentration of the water bodies in water quality based on the absorption peak characteristics of the COD concentration according to Lambert-Beer's law, and can quickly evaluate the degree of pollution of the water bodies in water quality by organic matter. However, due to the complexity of the turbidity components contained in the water bodies in water quality, it will have a certain turbidity interference effect on the absorption peak characteristics of the COD concentration, making it impossible to accurately analyze the absorption peak characteristics of the COD concentration, resulting in poor accuracy of detecting the COD concentration of the water bodies in water quality. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of this application is to provide a water quality detection method and device for environmental protection detection, and the specific technical solutions adopted are as follows:

[0005] The embodiment of this application provides a water quality detection method for environmental protection detection, including the following steps:

[0006] Respectively obtain the ultraviolet absorption spectra of the water body to be detected and the standard COD solution, and record them as the ultraviolet absorption spectrum to be detected and the standard ultraviolet absorption spectrum;

[0007] Respectively perform modal decomposition on the ultraviolet absorption spectrum to be detected and the standard ultraviolet absorption spectrum, and extract each modal component to be analyzed and each standard modal component;

[0008] Analyze the difference change situation of the wavelengths corresponding to the peak positions between the modal components to be analyzed and the standard modal components, construct the change coefficient of the peak position difference between the modal components to be analyzed and the standard modal components, and combine the average level of the wavelength difference corresponding to the peak position between the modal components to be analyzed and the standard modal components to obtain the turbidity interference factor of the modal components to be analyzed;

[0009] Determine the peak difference consistency of the modal vector to be analyzed according to the fluctuation of the difference between the modal vector to be analyzed and the standard modal vector with respect to each peak height.

[0010] Construct the superimposed interference eigenvalue of each modal vector to be analyzed according to the turbidity interference factor and the peak difference consistency of each modal vector to be analyzed. Extract the COD absorbance component vector in the ultraviolet absorption spectrum to be measured based on the superimposed interference eigenvalues of all modal components to be analyzed, and obtain the ultraviolet absorption spectrum after turbidity interference elimination through wavelet fusion.

[0011] Use Lambert-Beer's law in combination with the ultraviolet absorption spectrum after turbidity interference elimination to perform spectral measurement on the COD concentration in the water quality to be measured, and obtain the COD concentration in the water quality to be measured.

[0012] Preferably, the extraction of each modal component to be analyzed and each standard modal component specifically includes:

[0013] Construct the absorbance vector to be analyzed and the standard absorbance vector, and use each modal component after modal decomposition of the absorbance vector to be analyzed as the modal component to be analyzed.

[0014] Perform modal decomposition on the standard absorbance vector, calculate the discrete coefficient of each modal vector of the standard absorbance vector, use the average value of the discrete coefficients of all modal vectors of the standard absorbance vector as the judgment threshold, and record all modal vectors with discrete coefficients greater than or equal to the judgment threshold as standard modal vectors.

[0015] Preferably, the construction of the absorbance vector to be analyzed and the standard absorbance vector further includes:

[0016] Arrange all absorbance data in the ultraviolet absorption spectrum to be measured in ascending order of wavelength to form the absorbance vector to be analyzed, and arrange all absorbance data in the standard ultraviolet absorption spectrum in ascending order of wavelength to form the standard absorbance vector.

[0017] Preferably, the corresponding calculation formula for the variation coefficient of the peak position difference between the modal component to be analyzed and the standard modal component is:

[0018] ; where is the variation coefficient of the peak position difference between the i-th modal vector to be analyzed and the j-th standard modal vector, is the exponential normalization function, is the number of elements in the peak position difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector, and They are respectively the k-th and (k - 1)-th elements in the peak position difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector.

[0019] Preferably, the construction of the peak position difference vector further includes:

[0020] For each modal vector to be analyzed and each standard modal vector, respectively, a vector formed by arranging the wavelengths corresponding to all peak positions in the modal vector to be analyzed and the standard modal vector according to the peak positions is denoted as the peak position wavelength vector of the modal vector to be analyzed and the peak position wavelength vector of the standard modal vector;

[0021] The difference vector between the modal vector to be analyzed and the standard modal vector with respect to the peak position wavelength vector is denoted as the peak position difference vector between the modal vector to be analyzed and the standard modal vector.

[0022] Preferably, the calculation formula for the turbidity interference factor of the modal component to be analyzed is:

[0023] ; where is the turbidity interference factor of the i-th modal vector to be analyzed, is the number of standard modal vectors, is the mean value of the elements in the peak position difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector.

[0024] Preferably, the calculation formula for the peak difference consistency of the modal vector to be analyzed is:

[0025] ; where is the peak difference consistency of the i-th modal vector to be analyzed, is the exponential function with the natural constant as the base, is the information entropy of the peak height difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector. Among them, the heights of all peak positions in the i-th modal vector to be analyzed and the j-th standard modal vector are respectively sorted according to the peak positions to form the peak position height vector of the i-th modal vector to be analyzed and the peak position height vector of the j-th standard modal vector. The difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector with respect to the peak position height vector is denoted as the peak height difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector.

[0026] Preferably, the superimposed interference eigenvalue of each modal vector to be analyzed is the ratio of the turbidity interference factor to the peak difference consistency of each modal vector to be analyzed.

[0027] Preferably, the extraction of the COD absorbance component vector further includes:

[0028] Threshold segmentation is performed on the superimposed interference eigenvalues of all modal vectors to be analyzed to obtain a segmentation threshold. The modal vectors to be analyzed with superimposed interference eigenvalues lower than the segmentation threshold are denoted as COD absorbance component vectors.

[0029] The embodiment of the present application also provides a water quality detection device for environmental protection detection, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of the method described in any one of the above are implemented.

[0030] As can be seen from the above, a water quality detection method and device for environmental protection detection provided by the present application have at least the following beneficial effects:

[0031] The present application considers the peak position difference characteristics between the modal vectors corresponding to the water quality to be measured and the standard modal vectors, and also considers the change characteristics of the peak value difference when the modal that absorbs ultraviolet light is interfered by the turbidity component. The weighted summation method is used to measure the turbidity interference characteristics of the modal, so that the measurement result of the turbidity interference characteristics can reflect the difference change of the modal peak value between the water quality to be measured and the absorbent substance of the standard COD solution, and improve the accuracy of measuring the turbidity component interference characteristics in different modes of the water quality to be measured that absorb ultraviolet light.

[0032] At the same time, combining the consistency characteristics of the peak height difference between the modal vectors corresponding to the water quality to be measured and the standard modal vectors, the superimposed interference eigenvalue is obtained by using the turbidity interference factor and the peak value difference consistency, and the turbidity component interference in the ultraviolet absorption spectrum is eliminated by using the superimposed interference eigenvalue. Then, according to the ultraviolet absorption spectrum after turbidity interference elimination, the Lambert-Beer law is used to more accurately measure the COD concentration in the water body of the water quality to be measured, avoiding the problem that the complex turbidity components contained in the water body in the water quality have a certain turbidity interference effect on the absorption peak characteristics of the COD content, improving the accuracy of detecting the COD content in the water body of the environmental protection water quality, and realizing more accurate detection of the environmental protection water quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0034] Figure 1 It is a flowchart of the steps of a water quality detection method for environmental protection detection provided by the present application;

[0035] Figure 2Schematic diagram of the ultraviolet absorption spectrum to be measured provided by this application;

[0036] Figure 3 Schematic diagram of the standard ultraviolet absorption spectrum provided by this application. Detailed implementation manners

[0037] In order to further elaborate on the technical means and effects adopted by this application to achieve the intended invention purpose, the following, in combination with the accompanying drawings and preferred embodiments, details the specific implementation manners, structures, features, and effects of a water quality detection method and device for environmental protection detection proposed according to this application. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0038] Unless otherwise specified and limited, terms such as "including", "comprising", or any other variant thereof are intended to cover non-exclusive inclusion, so that a circuit structure, article, or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the article or device including the said element. Additionally, the term "and / or" used herein includes any and all combinations of one or more of the related listed items. All technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs.

[0039] The following specifically describes the specific solution of a water quality detection method and device for environmental protection detection provided by this application in conjunction with the accompanying drawings.

[0040] Please refer to Figure 1 , which shows a flowchart of the steps of a water quality detection method for environmental protection detection provided by an embodiment of this application, including the following steps:

[0041] Step 1: Respectively obtain the ultraviolet absorption spectra of the water quality to be measured and the standard COD solution, and record them as the ultraviolet absorption spectrum to be measured and the standard ultraviolet absorption spectrum.

[0042] The purpose of this embodiment is to analyze the superimposed interference characteristics of the ultraviolet absorption spectrum of the water body in the water quality, eliminate the turbidity component interference in the ultraviolet absorption spectrum, and more accurately analyze the absorption peak characteristics of the COD concentration based on the ultraviolet absorption spectrum after eliminating the turbidity interference, so as to improve the accuracy of detecting the COD concentration of the water body in environmental protection water quality.

[0043] Measure the ultraviolet absorption spectra of water bodies in water quality at each measurement moment through a spectral measurement device. The spectral measurement device includes a light source, an optical path, an ultraviolet-visible spectrophotometer, and a host computer. The light source is used to emit ultraviolet light in a specific wavelength range. The optical path is used to guide the ultraviolet light emitted by the light source into the water body of the water quality and transmit the ultraviolet light absorbed by the water body of the water quality to the ultraviolet-visible spectrophotometer. The ultraviolet-visible spectrophotometer is used to measure the ultraviolet absorption spectra of the water bodies in the water quality, and the host computer is used to store the ultraviolet absorption spectra of the water bodies in the water quality.

[0044] Since the COD concentration has strong ultraviolet light absorption characteristics in the ultraviolet wavelength range of 200 - 300 nm, and there is a strong corresponding relationship between the ultraviolet absorption intensity and the COD concentration in this ultraviolet wavelength range. Therefore, in this embodiment, the light source in the spectral measurement device emits ultraviolet light in the wavelength range of 200 - 300 nm, and the ultraviolet-visible spectrophotometer measures the ultraviolet absorption spectra of the water bodies in the water quality, which is recorded as the ultraviolet absorption spectra to be measured. Specifically, as Figure 2 shown, Figure 2 where the abscissa is the wavelength, with the unit of nm, and the ordinate is the absorbance. At the same time, the ultraviolet-visible spectrophotometer measures the ultraviolet absorption spectra of standard COD solutions in the concentration range of 20 - 40 mg / L, which is recorded as the standard ultraviolet absorption spectra. Specifically, as Figure 3 shown, Figure 3 where the abscissa is the wavelength, with the unit of nm, and the ordinate is the absorbance. In this embodiment, the resolution of the ultraviolet absorption spectra is 1 nm, and the concentration of the standard COD solution is 30 mg / L. In actual application scenarios, the implementer can select the concentration of the standard COD solution and set the ultraviolet wavelength range by themselves.

[0045] Step 2: Perform modal decomposition on the ultraviolet absorption spectra to be measured and the standard ultraviolet absorption spectra respectively, and extract each modal component to be analyzed and each standard modal component.

[0046] During the measurement of the ultraviolet absorption spectra of water bodies in water quality, it will be affected by turbidity interference components, such as sediment, colloidal particles, and plankton in the water body of the water quality, etc. These turbidity interference components will all have a superimposed interference effect on the absorption peaks of the COD concentration in the ultraviolet absorption spectra, making it impossible to accurately analyze the absorption peak characteristics of the COD concentration in the water body, and ultimately affecting the accuracy of spectral detection of the COD concentration in the water body. Therefore, in order to improve the accuracy of spectral detection of the COD concentration in the water body and more accurately evaluate the degree of water quality pollution, it is necessary to accurately analyze the superimposed interference characteristics in the ultraviolet absorption spectra to be measured and eliminate the turbidity component interference in the ultraviolet absorption spectra.

[0047] The vector formed by arranging all the absorbance data in the ultraviolet absorption spectrum to be measured in ascending order of wavelength is denoted as the absorbance vector to be analyzed. The absorbance vector to be analyzed reflects the absorbance intensity characteristics of COD concentration on ultraviolet light under the interference of turbidity components in water. Similarly, the standard ultraviolet absorption spectrum is processed in the same way to obtain the standard absorbance vector, which is used to reflect the absorbance intensity characteristics of COD concentration on ultraviolet light without the interference of turbidity components in water.

[0048] In order to extract the modal component characteristics of COD concentration absorbing ultraviolet light in different wavelength ranges under the condition of excluding the interference of turbidity components in water, the standard absorbance vector is input into the modal decomposition algorithm, and the modal vectors of the standard COD solution absorbing ultraviolet light are obtained by using the modal component decomposition algorithm respectively. Similarly, for the absorbance vector to be analyzed, the modal decomposition algorithm is used to extract the modal vectors of the absorbance vector to be analyzed, which are denoted as the modal components to be analyzed. The modal decomposition algorithm can specifically be the VMD variational mode decomposition algorithm (Variational Mode Decomposition), the EMD empirical mode decomposition algorithm (Empirical Mode Decomposition), or the EEMD ensemble empirical mode decomposition (Ensemble Empirical Mode Decomposition). In this embodiment, there is no limitation on the specific algorithm of modal decomposition. In this embodiment, the VMD variational mode decomposition algorithm is selected. The preset number of modes in the algorithm is 10, the penalty coefficient is 2000, and the convergence tolerance is 3e-6. The VMD variational mode decomposition algorithm is used to obtain the modal vectors of the standard COD solution absorbing ultraviolet light. The VMD variational mode decomposition algorithm is a well-known technology, and the specific process will not be elaborated.

[0049] Furthermore, to avoid the modal vectors of the extracted standard absorbance vector containing invalid modal vectors, the dispersion degree of each modal vector of the standard absorbance vector is calculated. The mean value of the dispersion degrees of all the modal vectors of the standard absorbance vector is used as the judgment threshold. The modal vectors with the dispersion degree greater than or equal to the judgment threshold are denoted as the standard modal vectors. The measurement method of the dispersion degree can adopt variance, standard deviation, and coefficient of variation, and the measurement method is not specifically limited. In this embodiment, the coefficient of variation is used to measure the dispersion degree of each modal vector. The coefficient of variation is a well-known technology, and the specific process will not be elaborated. The standard modal vectors reflect the modal component characteristics of COD concentration absorbing ultraviolet light in different wavelength ranges, and this modal component characteristic is not affected by the interference of turbidity components, and can accurately reflect the modal characteristics of the absorbance of the standard COD solution.

[0050] Step 3: Analyze the difference in the wavelengths corresponding to the peak positions between the modal component to be analyzed and the standard modal component for each peak position, so as to obtain the turbidity interference factor of the modal component to be analyzed.

[0051] In order to analyze the superimposed interference characteristics of the ultraviolet absorption spectrum of water bodies in water quality and eliminate the interference of the turbidity component in the ultraviolet absorption spectrum, in this embodiment, peak detection is performed on each modal component to be analyzed and each standard modal component, and the difference in peak characteristics is analyzed. Specifically, the i-th modal vector to be analyzed and the j-th standard modal vector are input into the AMPD peak detection algorithm (Automatic multiscale-based peak detection), and all peak positions in the i-th modal vector to be analyzed and the j-th standard modal vector are obtained respectively by using the AMPD peak detection algorithm. The AMPD peak detection algorithm is a well-known technology, and the specific process will not be elaborated here.

[0052] Furthermore, the vectors formed by arranging the wavelengths corresponding to all peak positions in the i-th modal vector to be analyzed and the j-th standard modal vector in the order of the peak positions are respectively denoted as the peak position wavelength vectors of the i-th modal vector to be analyzed and the j-th standard modal vector.

[0053] Furthermore, the difference vector between the modal vector to be analyzed and the standard modal vector with respect to the peak position wavelength vector is denoted as the peak position difference vector between the modal vector to be analyzed and the standard modal vector. In this embodiment, to ensure the calculation of the difference vector between different peak position wavelength vectors, the peak position wavelength vector with more elements is subjected to a truncation operation, that is, the heads of the two peak position wavelength vectors are aligned, and the redundant elements at the tail of one of the peak position wavelength vectors are deleted to make the lengths of the two peak position wavelength vectors the same. Specifically, in this embodiment, the peak position wavelength vectors of the i-th modal vector to be analyzed and the j-th standard modal vector are subjected to vector alignment processing, and after alignment, the difference vector between the peak position wavelength vectors of the i-th modal vector to be analyzed and the j-th standard modal vector is calculated, which is denoted as the peak position difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector. It should be noted that in this embodiment, the method of vector alignment processing for the peak position wavelength vectors of the i-th modal vector to be analyzed and the j-th standard modal vector is to align the heads of the two peak position wavelength vectors and delete the elements at the redundant tail of the peak position wavelength vector with more elements. In actual application scenarios, the implementer can also perform a zero-padding operation on the peak position wavelength vector with fewer elements. The specific padding method is not specially limited in this embodiment, and the implementer can set it by himself.

[0054] The peak position difference vector reflects the peak position difference in the modal characteristics of the ultraviolet light absorption of the water body to be measured and the standard COD solution. Since when the pollution components in the water body increase, it will change the height of the peak value in the modal characteristics, but will not change the position of the peak value in the modal characteristics. If the average level of the peak position difference in the peak position difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector is higher and the change between consecutive peak position differences is greater, it can better indicate that this mode is formed by the interference of the turbidity component in the water quality, and will have a greater superimposed interference effect on the ultraviolet absorption spectrum of the water body.

[0055] Through the above analysis, calculate the coefficient of variation of the peak position difference between each modal vector to be analyzed and each standard modal vector. In this embodiment, the specific calculation formula is:

[0056] ; where, is the coefficient of variation of the peak position difference between the i-th modal vector to be analyzed and the j-th standard modal vector, is the exponential normalization function, is the number of elements in the peak position difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector, and are respectively the k-th and (k - 1)-th elements in the peak position difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector.

[0057] The greater the change between consecutive peak position differences in the peak position difference vector, the more inconsistent the peak position differences in the modal characteristics between the i-th modal vector to be analyzed and the j-th standard modal vector are reflected, indicating a greater difference in the light-absorbing substances between the water quality to be measured and the standard COD solution. Since the light-absorbing substance in the standard COD solution is the COD pollutant, this mode is more likely to be formed by the interference of the turbidity component and will have a greater superimposed interference effect on the ultraviolet absorption spectrum of the water quality to be measured. Therefore, according to the coefficient of variation of the peak position difference between the modal component to be analyzed and the standard modal component, combined with the average level of the wavelength difference corresponding to the peak position between the modal component to be analyzed and the standard modal component, obtain the turbidity interference factor of the modal component to be analyzed. In this embodiment, the specific calculation formula is:

[0058] ; where, is the turbidity interference factor of the i-th modal vector to be analyzed, is the number of standard modal vectors, is the average value of the elements in the peak position difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector.

[0059] Considering the variation characteristics of the peak difference when the ultraviolet light absorption mode is interfered by turbidity components, the coefficient of variation of the peak difference is used as the weight of the average level of the peak difference, and the weighted sum is used to measure the turbidity interference characteristics of the mode, so that the measurement result of the turbidity interference characteristics can reflect the difference change of the modal peak between the water quality to be measured and the light-absorbing substances in the standard COD solution, and improve the accuracy of measuring the turbidity interference characteristics in different modes of the water quality to be measured absorbing ultraviolet light.

[0060] Step 4: Determine the peak difference consistency of the modal vector to be analyzed according to the fluctuation of the difference between the modal vector to be analyzed and the standard modal vector in terms of the height of each peak.

[0061] At the same time, the difference between the COD concentration in the water body of the water quality to be measured and the COD concentration in the standard COD solution will cause the height of the peak position in the mode of COD concentration absorbing ultraviolet light to show a linear change. If the consistency of the differences in height at all peak positions between the modal vector corresponding to the water quality to be measured and the standard modal vector corresponding to the standard COD solution is higher, it can better reflect the linear change characteristics of the height of the peak position in the mode of COD concentration absorbing ultraviolet light with the COD concentration, that is, the modal vector corresponding to the water quality to be measured can better reflect the modal characteristics of COD concentration absorbing ultraviolet light.

[0062] Furthermore, the vectors formed by arranging the heights at all peak positions in the i-th modal vector to be analyzed and the j-th standard modal vector in the order of peak position are respectively denoted as the peak position height vectors of the i-th modal vector to be analyzed and the j-th standard modal vector, and the difference vector between the peak position height vectors of the i-th modal vector to be analyzed and the j-th standard modal vector is calculated, denoted as the peak height difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector. The higher the consistency of the peak height differences in the peak height difference vector, the better it can reflect the linear change characteristics of the height of the peak position in the mode of COD concentration absorbing ultraviolet light with the COD concentration.

[0063] Through the above analysis, according to the fluctuation of the difference between the modal vector to be analyzed and the standard modal vector in terms of the height of each peak, calculate the peak difference consistency of each modal vector of the absorbance vector to be analyzed. In this embodiment, the specific calculation formula is:

[0064] ; where is the peak difference consistency of the i-th modal vector to be analyzed, is the exponential function with the natural constant as the base, is the information entropy of the peak height difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector. It should be noted that the information entropy is a well-known technology, and the specific process will not be elaborated here.

[0065] The lower the degree of chaos of the peak height difference vector, the higher the consistency of the height differences at all peak positions between each modal vector to be measured corresponding to the water quality to be measured and each standard modal vector corresponding to the standard COD solution, and the more the modal vector corresponding to the water quality to be measured can reflect the modal characteristics of the COD concentration absorbing ultraviolet light.

[0066] Step 5: According to the turbidity interference factors and peak difference consistency degrees of each modal vector to be analyzed, construct the superimposed interference eigenvalue of each modal vector to be analyzed. Based on the superimposed interference eigenvalues of all modal components to be analyzed, extract the COD absorption component vector in the ultraviolet absorption spectrum to be measured, and obtain the ultraviolet absorption spectrum after turbidity interference elimination through wavelet fusion.

[0067] Furthermore, in order to more accurately eliminate the interference of the turbidity component in the ultraviolet absorption spectrum, and more accurately analyze the absorption peak characteristics of the COD concentration based on the ultraviolet absorption spectrum after turbidity interference elimination, so as to improve the accuracy of detecting the COD concentration in water quality for environmental protection.

[0068] The ratio of the turbidity interference factor to the peak difference consistency degree of each modal vector to be analyzed corresponding to the water body absorbing ultraviolet light in the water quality to be measured is denoted as the superimposed interference eigenvalue of each modal vector to be analyzed. The superimposed interference eigenvalue reflects the superimposed interference effect of the turbidity generated by this modal component on the ultraviolet absorption spectrum of the water quality to be measured. The larger the superimposed interference eigenvalue, the easier it is to generate the superimposed interference of turbidity on the ultraviolet absorption spectrum of the water quality to be measured.

[0069] In order to more accurately eliminate the interference of the turbidity component in the ultraviolet absorption spectrum, input the superimposed interference eigenvalues of all modal vectors to be analyzed corresponding to the water body absorbing ultraviolet light in the water quality to be measured into the maximum inter-class variance algorithm. Use the maximum inter-class variance algorithm to obtain the segmentation threshold. Denote the modal vectors to be analyzed with superimposed interference eigenvalues higher than the segmentation threshold as turbidity interference component vectors, and denote the modal vectors to be analyzed with superimposed interference eigenvalues lower than the segmentation threshold as COD absorption component vectors; then, fuse all the COD absorption component vectors of the water body absorbing ultraviolet light in the water quality to be measured, input all the COD absorption component vectors into the wavelet fusion algorithm, and use the wavelet fusion algorithm to obtain the ultraviolet absorption spectrum after turbidity interference elimination, where the maximum inter-class variance algorithm and the wavelet fusion algorithm are both well-known technologies, and the specific process will not be elaborated.

[0070] Step 6: Adopt Lambert-Beer's law and combine it with the ultraviolet absorption spectrum after turbidity interference elimination to perform spectral measurement on the COD concentration in the water body of the water quality to be measured, and obtain the COD concentration in the water body of the water quality to be measured.

[0071] Furthermore, the ultraviolet absorption spectrum after turbidity interference elimination can more accurately reflect the light absorption intensity characteristics of the COD concentration in the water quality to be measured on the ultraviolet light. The wavelength corresponding to the absorption peak in the ultraviolet absorption spectrum after turbidity interference elimination is denoted as the characteristic wavelength of the COD concentration absorption peak. According to the characteristic wavelength of the COD concentration absorption peak in the ultraviolet absorption spectrum after turbidity interference elimination and the corresponding absorbance A, the Lambert-Beer law is adopted: where is the molar absorption coefficient, is the detection optical path, is the concentration of COD. The Lambert-Beer law is used to obtain the COD concentration in the water body of the water quality to be measured. The higher the COD concentration in the water body of the water quality to be measured, the higher the degree of pollution of the water quality to be measured. Among them, the process of measuring the COD concentration using the Lambert-Beer law is a well-known technology, and the specific process in this embodiment will not be elaborated.

[0072] Based on the same inventive concept as the above method, an embodiment of the present application also provides a water quality detection device for environmental protection detection, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of any one of the above methods for water quality detection in environmental protection detection are implemented.

[0073] It can be understood that the above sequence of embodiments of the present application is only for description and does not represent the advantages and disadvantages of the embodiments. And the above specific embodiments of this specification have been described. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0074] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments.

[0075] The above content is only the implementation manner of the present application and is not used to limit the scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied to other related technical fields, is equally included in the protection scope of the present application.

Claims

1. A water quality detection method for environmental protection detection, characterized in that It includes the following steps: Obtain the ultraviolet absorption spectra of the water quality to be measured and the standard COD solution respectively, and record them as the ultraviolet absorption spectrum to be measured and the standard ultraviolet absorption spectrum; Perform modal decomposition on the ultraviolet absorption spectrum to be measured and the standard ultraviolet absorption spectrum respectively, and extract each modal component to be analyzed and each standard modal component; Analyze the difference change situation of the wavelengths corresponding to the peak positions between the modal components to be analyzed and the standard modal components, construct the change coefficient of the peak position difference between the modal components to be analyzed and the standard modal components, and combine the average level of the wavelength difference corresponding to the peak positions between the modal components to be analyzed and the standard modal components to obtain the turbidity interference factor of the modal components to be analyzed; Determine the peak difference consistency of the modal vector to be analyzed according to the fluctuation situation of the difference between the modal vector to be analyzed and the standard modal vector regarding the peak heights; Construct the superimposed interference eigenvalue of each modal vector to be analyzed according to the turbidity interference factor and the peak difference consistency of each modal vector to be analyzed. Extract the COD absorbance component vector in the ultraviolet absorption spectrum to be measured based on the superimposed interference eigenvalues of all modal components to be analyzed, and obtain the ultraviolet absorption spectrum after turbidity interference elimination through wavelet fusion; Use Lambert-Beer's law in combination with the ultraviolet absorption spectrum after turbidity interference elimination to perform spectral measurement on the COD concentration in the water quality to be measured, and obtain the COD concentration in the water quality to be measured.

2. The water quality detection method for environmental protection detection according to claim 1, wherein The extraction of each modal component to be analyzed and each standard modal component specifically includes: Construct the absorbance vector to be analyzed and the standard absorbance vector, and use each modal component after modal decomposition of the absorbance vector to be analyzed as the modal component to be analyzed; Perform modal decomposition on the standard absorbance vector, calculate the discrete coefficient of each modal vector of the standard absorbance vector, use the average value of the discrete coefficients of all modal vectors of the standard absorbance vector as the judgment threshold, and record all modal vectors with a discrete coefficient greater than or equal to the judgment threshold as standard modal vectors.

3. The water quality detection method for environmental protection detection according to claim 2, wherein The construction of the absorbance vector to be analyzed and the standard absorbance vector further includes: Arrange all the absorbance data in the ultraviolet absorption spectrum to be measured in ascending order of wavelength to form the absorbance vector to be analyzed, and arrange all the absorbance data in the standard ultraviolet absorption spectrum in ascending order of wavelength to form the standard absorbance vector.

4. The water quality detection method for environmental protection detection according to claim 1, characterized in that, The corresponding calculation formula for the change coefficient of the peak position difference between the modal component to be analyzed and the standard modal component is: ; wherein, is the variation coefficient of the peak position difference between the i-th modal vector to be analyzed and the j-th standard modal vector, is the exponential normalization function, is the number of elements in the peak position difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector, and are the k-th and (k - 1)-th elements in the peak position difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector, respectively.

5. The water quality detection method for environmental protection detection according to claim 4, wherein The construction of the peak position difference vector further includes: For each modal vector to be analyzed and each standard modal vector, respectively arrange the wavelengths corresponding to all peak positions in the modal vector to be analyzed and the standard modal vector in the order of peak positions to form a vector, and record it as the peak position wavelength vector of the modal vector to be analyzed and the peak position wavelength vector of the standard modal vector; Record the difference vector between the modal vector to be analyzed and the standard modal vector regarding the peak position wavelength vector as the peak position difference vector between the modal vector to be analyzed and the standard modal vector.

6. The water quality detection method for environmental protection detection according to claim 5, characterized in that, The calculation formula for the turbidity interference factor of the modal component to be analyzed is: ; wherein, is the turbidity interference factor of the i-th modal vector to be analyzed, is the number of standard modal vectors, is the mean value of the elements in the peak position difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector.

7. The water quality detection method for environmental protection detection according to claim 1, wherein The calculation formula for the peak difference consistency of the modal vector to be analyzed is: ; where, is the peak difference consistency of the i-th modal vector to be analyzed, is the exponential function with the natural constant as the base, is the information entropy of the peak height difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector. Among them, the heights of all peak positions in the i-th modal vector to be analyzed and the j-th standard modal vector are sorted according to the peak positions respectively to form the peak position height vector of the i-th modal vector to be analyzed and the peak position height vector of the j-th standard modal vector. The difference vector of the peak position height vectors between the i-th modal vector to be analyzed and the j-th standard modal vector is denoted as the peak height difference vector between the i-th modal vector to be analyzed and the j-th standard modal vector.

8. The water quality detection method for environmental protection detection according to claim 1, wherein The superimposed interference eigenvalue of each modal vector to be analyzed is the ratio of the turbidity interference factor of each modal vector to be analyzed to the peak difference consistency.

9. The water quality detection method for environmental protection detection according to claim 1, characterized in that, The extraction of the COD absorbance component vector further includes: Performing threshold segmentation on the superimposed interference eigenvalues of all modal vectors to be analyzed to obtain a segmentation threshold, and denoting the modal vectors to be analyzed with superimposed interference eigenvalues lower than the segmentation threshold as the COD absorbance component vectors.

10. An environmental protection detection water quality detection device, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1-9.

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