Laser-induced breakdown spectroscopy spectral line peak shape correction method and system, electronic equipment and medium

Abstract

The invention discloses a laser-induced breakdown spectroscopy spectral line peak shape correction method and system, electronic equipment and a medium. A Gaussian function and an exponential function describing preposition / trailing are used for convolution to fit an original peak shape needing to be corrected; spectrum peaks needing to be corrected are determined; calculating the ridge slope of the spectral line peak shape on one side needing to be adjusted, and adjusting the spectral line peak shape of the spectral peak to change the ridge slope by taking the ridge slope of the ideal spectral line peak shape of the spectral peak as a reference, so that the ridge slope tends to the ridge slope of the side corresponding to the ideal spectral line peak shape; correcting the spectral line peak shape of the spectral peak; and finally, fitting the corrected peak shape curve by a Gaussian function, and analyzing component elements and concentration of the sample. According to the method, the preposition or trailing effect is improved by changing the slope of the peak shape of the signal spectral line, it is ensured that the fitting curve can be more tightly attached to the actual data point, main spectral characteristics can be extracted, the peak shape is steeper, and therefore the analysis precision is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of spectrum analysis, and in particular to a method, system, electronic equipment and medium for correcting the peak shape of a laser induced breakdown spectrum line. Background Art

[0002] Laser induced breakdown spectroscopy (LIBS) is an emerging spectral analysis technology that is widely used in geology, chemistry, environmental science, material science, etc. It provides an effective solution for material surface analysis, elemental composition detection and environmental monitoring with its rapid, non-contact, high sensitivity and multi-element simultaneous detection characteristics.

[0003] In the LIBS process, continuous background interferences such as blackbody radiation, bremsstrahlung and load radiation can cause spectral baseline drift. Blackbody radiation originates from high-temperature electrons and ions in the plasma, forming a strong thermal radiation background; bremsstrahlung is continuous X-ray radiation produced when high-speed electrons interact with atomic nuclei; and load radiation is continuous radiation formed by the energy released when electrons recombine. These background interferences not only increase the spectral baseline, mask low-intensity characteristic spectral lines, reduce the signal-to-noise ratio and resolution of the spectrum, but also affect the accuracy of quantitative analysis based on peak intensity or integrated area. To reduce the impact of these interferences, a variety of methods can be used: select the best measurement parameters, apply filtering techniques (such as exponential decay filters and wavelet transforms) to smooth the signal, use complex peak fitting models (such as GHVL) to correct asymmetric peak shapes, and optimize experimental conditions (such as laser energy, pulse width, and focusing distance) to improve the stability of the plasma and the quality of the spectrum. These methods can effectively reduce background interference, thereby improving the resolution of LIBS data and the accuracy of quantitative analysis.

[0004] Although LIBS technology has shown significant advantages in multi-element detection and its high sensitivity makes it a powerful tool in related detection tasks, it still faces challenges in practical applications. For example, due to system deviations and the evolution of plasma at high temperatures, asymmetric peaks appear in the spectral lines, such as front drift or tail extension. This affects the reliability and accuracy of the analysis results. Summary of the invention

[0005] Technical purpose: In view of the shortcomings of existing LIBS spectral analysis, the present invention discloses a method, system, electronic equipment and medium for correcting the peak shape of laser induced breakdown spectroscopy lines.

[0006] Technical solution: To achieve the above technical objectives, the present invention adopts the following technical solution:

[0007] A method for correcting the peak shape of a laser induced breakdown spectroscopy line comprises the steps of:

[0008] S01. Obtain the LIBS spectrum of the sample through spectral measurement and observe the spectral peak;

[0009] S02, convolve the Gaussian function with the exponential function describing the leading / trailing to fit the original peak shape;

[0010] S03. For the fitted spectral peak curve, calculate the half-width, asymmetry factor, leading or tailing factor of the spectral peak line peak shape; determine the spectral peak that needs to be corrected;

[0011] S04. Calculate the ridge slope of the spectral line peak shape on one side that needs to be adjusted, and use the ridge slope of the ideal spectral line peak shape of the spectral peak as a reference to adjust the ridge slope of the spectral line peak shape of the spectral peak so that the ridge slope tends to the ridge slope on the corresponding side of the ideal spectral line peak shape; correct the spectral line peak shape of the spectral peak; finally, fit the corrected peak shape curve with a Gaussian function to analyze the composition elements and concentration of the sample.

[0012] Preferably, in step S02 of the present invention, the process of fitting the original peak shape includes: using a Gaussian distribution function to fit the spectral peak to obtain an initial Gaussian peak shape f(x), and using an exponential function E(x) for the leading peak or the trailing peak part. t ) to indicate, T is the original spectrum peak tailing factor, x t It is the intersection of the peak with the peak at 5% of the peak height; the exponentially modified Gaussian function model curve obtained after convolution is y EMG =f(x)*E(x t ).

[0013] Preferably, in step S04 of the present invention, the process of adjusting the spectral line peak shape of the spectral peak to change the ridge slope includes: converting the ridge slope into a corresponding inclination angle, and confirming the inclination angle adjustment range according to the difference between the spectral line peak shape of the spectral peak and the inclination angle of the ideal spectral line peak shape of the spectral peak, adjusting the spectral line peak shape of the spectral peak with 1° as a step unit, and after each adjustment, calculating the half-width at half height of the adjusted spectral line peak shape until the final half-width position point is symmetrical with the spectral line peak shape on the other side, at which time the ridge slope of the spectral line peak shape of the spectral peak is consistent with the ridge slope of the ideal spectral line peak shape.

[0014] Preferably, when calculating the ridge slope of the spectral peak shape and the spectral peak ideal line shape, the present invention uses the intersection point from the spectral peak apex to the corresponding peak shape and the peak height of 5% as the endpoint for calculating the slope.

[0015] Preferably, before performing the original peak shape fitting in step S02, the present invention first segments the ridge line on the leading or trailing side using the nodes corresponding to the half-width position of the spectral peak of the original peak shape as the dividing points, calculates the ridge line slope from the half-width position to the peak top and the slope from the half-width position to the peak bottom of the spectrum line, first modulates the slope from the half-width position to the peak bottom to be consistent with the ridge line slope from the half-width position to the peak top, and then fits the peak shape.

[0016] The invention discloses a laser induced breakdown spectrum tailing adaptive correction system, which uses the correction method to correct the laser induced breakdown spectrum.

[0017] The present invention discloses an electronic device, comprising a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the program, a method for correcting the peak shape of a laser induced breakdown spectroscopy line as described in any one of claims 1 to 6 is implemented.

[0018] A computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to execute the above-mentioned laser induced breakdown spectroscopy line peak shape correction method.

[0019] Beneficial effects: The method, system, electronic device and medium disclosed in the present invention for correcting the peak shape of a laser-induced breakdown spectroscopy spectrum line have the following beneficial effects:

[0020] 1. The present invention improves the leading or tailing effect by changing the slope of the signal spectrum peak, ensuring that the fitting curve can fit the actual data points more closely, and can extract the main spectral features to make the peak steeper, thereby improving the accuracy of the analysis.

[0021] 2. The present invention uses a Gaussian function and an exponential function describing the leading or trailing to perform convolution to fit the original peak shape, and pre-processes the peak shape to adjust the asymmetric part of the peak shape, thereby providing a more flexible and accurate fitting result, which is convenient for the subsequent adjustment of the peak ridge slope.

[0022] 3. Before fitting the original peak shape, the present invention pre-adjusts the area with severe leading or tailing according to the slopes of the upper and lower parts of the half-width position, thereby narrowing the scope of subsequent overall slope adjustment, improving the efficiency of spectrum correction, and ensuring the accuracy of the correction result. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0024] Figure 1 It is a schematic diagram of the peak shape curve of the spectral peak front and tailing state;

[0025] Figure 2 This is a schematic diagram of the original peak shape fitting of the present invention;

[0026] Figure 3 It is a schematic diagram of the process of adjusting the ridge slope of the spectrum peak-peak curve according to the present invention. DETAILED DESCRIPTION

[0027] Reference will now be made in detail to embodiments of the present disclosure, one or more examples of which are set forth herein below. Each embodiment and example is provided by way of explanation of the apparatus, composition and materials of the present disclosure, rather than limitation. On the contrary, the following description provides a convenient illustration of an exemplary embodiment for implementing the present disclosure. In fact, it will be clear to those skilled in the art that various modifications and variations may be made in the teachings of the present disclosure without departing from the scope or spirit of the present disclosure.

[0028] like Figure 1-Figure 3 As shown, the present invention discloses a method for correcting the peak shape of a laser induced breakdown spectroscopy line, comprising the steps of:

[0029] S01. Obtain the LIBS spectrum of the sample through spectral measurement and observe the spectral peak;

[0030] S02, convolve the Gaussian function with the exponential function describing the leading / trailing to fit the original peak shape;

[0031] In step S02 of the present invention, the process of fitting the original peak shape includes: fitting the spectral peak using a Gaussian distribution function to obtain an initial Gaussian peak shape f(x). Under the Gaussian peak shape, the spectral intensity is Where A is the peak area, x is the position of the peak half-height, x0 is the peak center, and σ is the standard deviation.

[0032] And for the trailing or leading part exponential function E(x t ) to indicate, T is the leading or tailing factor of the original spectrum peak, x t It is the intersection of the peak with the peak at 5% of the peak height; the exponentially modified Gaussian function model curve obtained after convolution is y EMG =f(x)*E(x t ), in order to describe the peak shape of the spectrum.

[0033] S03. For the fitted spectral peak curve, calculate the half-width, asymmetry factor, and leading or tailing factor of the spectral peak line peak shape; determine the spectral peak that needs to be corrected, and correct the spectral peak shape when leading or tailing occurs;

[0034] The present invention Figure 2A schematic diagram of the peak shape in the case of pre-positioning is given in FIG. In this case, it is necessary to correct the peak shape curve of the pre-positioning part on the left side of the figure to maintain the overall correction of the spectral peak line and eliminate the influence of the pre-positioning part on the spectral analysis.

[0035] In the present invention Figure 2 In the embodiment shown, the half-height width W 0.5h =a+b, a, b represent the distance from the center of the half-width height position of the peak curve to the left and right sides of the spectrum, a', b' represent the distance from the center of the height position of 5% peak height of the peak curve to the left and right sides of the spectrum; asymmetry factor leading or trailing factor; Where I(x t ) represents the spectral intensity at 5% of the spectral peak height, x t The horizontal coordinate represents the intersection of the peak height 5% and the peak shape line of the spectrum. When performing the peak shape correction of the spectrum line, the correction is also performed on the area with a peak height of more than 5%.

[0036] S04. Calculate the ridge slope of the spectral line peak shape on one side that needs to be adjusted, and use the ridge slope of the ideal spectral line peak shape of the spectral peak as a reference to adjust the ridge slope of the spectral line peak shape of the spectral peak, so that the ridge slope tends to the ridge slope of the corresponding side of the ideal spectral line peak shape; use the intersection of the spectral peak top to the corresponding peak shape and 5% of the peak height as the endpoint of the slope calculation, and correct the spectral line peak shape of the spectral peak; finally, fit the corrected peak shape curve with a Gaussian function to analyze the composition elements and concentration of the sample.

[0037] like Figure 3 As shown, in step S04 of the present invention, the process of adjusting the spectral line peak shape of the spectral peak to change the ridge slope includes: converting the ridge slope into a corresponding inclination angle, and confirming the inclination angle adjustment range according to the difference between the spectral line peak shape of the spectral peak and the inclination angle of the ideal spectral line peak shape of the spectral peak, adjusting the spectral line peak shape of the spectral peak with 1° as a step unit, and calculating the half-width at half height after each adjustment until the point at the final half-width position is symmetrical with the spectral line peak shape on the other side, at which time the ridge slope of the spectral line peak shape of the spectral peak is consistent with the ridge slope of the ideal spectral line peak shape.

[0038] The slope of the peak shape of the spectrum peak Spectral peak ideal line shape I(x0) is the spectral intensity at the top of the spectral peak, x 0.05h It is the horizontal coordinate of the intersection point of the peak height 5% and the ideal peak shape spectrum line of the spectral peak.

[0039] The corresponding tilt angle is:

[0040] θ1=tan -1 (m1)

[0041] θ2=tan-1 (m2)

[0042] The adjustment angle range is θ=θ1-θ2, and the displacement of the peak height before and after adjustment is 5% on the x-axis x'=x 0.05h -x t .

[0043] When the angle θ changes, the corresponding tilt angle will also change. Therefore, the spectral line peak shape of the spectrum peak can be gradually adjusted by angle step adjustment until a=b, m1=m2. At this point, the peak shape adjustment is completed. Finally, the adjusted peak shape can be fitted by a Gaussian function to remove the interference components of the front peak, which can significantly improve the spectral quality and make the spectrum more realistically reflect the characteristics of the sample. For the processing of tailing peaks, you can refer to the processing process of the front peak and make corresponding adjustments.

[0044] At the same time, when adjusting the leading part or the tailing part of the spectral peak, the actual leading part or the tailing part is mainly concentrated in the area below the half-width of the peak shape. Considering that in the case of severe leading or tailing, the slope deviation between the peak shape of the spectral peak spectral line and the ideal spectral line peak shape of the spectral peak is large, resulting in a large angle range that needs to be adjusted during correction, thereby increasing the difficulty of correction. For this reason, before the original peak shape is fitted in step S02, the present invention first segments the ridge line on the leading or tailing side with the node corresponding to the half-width position of the spectral peak of the original peak shape as the dividing point, calculates the ridge line slope from the half-width position to the peak top and the slope from the half-width position to the bottom of the peak of the spectral line, first modulates the slope from the half-width position to the bottom of the peak to be consistent with the ridge line slope from the half-width position to the peak top, and then fits the peak shape to further reduce the influence of the leading or tailing on the spectral peak, thereby greatly reducing the range of subsequent slope adjustment, improving the correction efficiency of the spectral peak shape, achieving rapid analysis of the sample spectral line, and correspondingly improving the detection efficiency.

Claims

1. A method for correcting the peak shape of a laser induced breakdown spectroscopy line, characterized in that: Includes steps: S01. Obtain the LIBS spectrum of the sample through spectral measurement and observe the spectral peak; S02, convolve the Gaussian function with the exponential function describing the leading / trailing to fit the original peak shape; S03. For the fitted spectral peak curve, calculate the half-width, asymmetry factor, leading or tailing factor of the spectral peak line peak shape; determine the spectral peak that needs to be corrected; S04. Calculate the ridge slope of the spectral line peak shape on one side that needs to be adjusted, and use the ridge slope of the ideal spectral line peak shape of the spectral peak as a reference to adjust the ridge slope of the spectral line peak shape of the spectral peak so that the ridge slope tends to the ridge slope on the corresponding side of the ideal spectral line peak shape; correct the spectral line peak shape of the spectral peak; finally, fit the corrected peak shape curve with a Gaussian function to analyze the composition elements and concentration of the sample.

2. A method for correcting the peak shape of a laser induced breakdown spectroscopy line according to claim 1, characterized in that: In step S02, the process of fitting the original peak shape includes: fitting the spectral peak using a Gaussian distribution function to obtain an initial Gaussian peak shape f(x), and fitting the tailing part using a tailing exponential function E(x t ) to indicate, T is the original spectrum peak tailing factor, x t It is the intersection of the peak with the peak at 5% of the peak height; the exponentially modified Gaussian function model curve obtained after convolution is y EMG =f(x)*E(x t ).

3. A method for correcting the peak shape of a laser induced breakdown spectroscopy line according to claim 2, characterized in that: In step S04, the process of adjusting the spectral line peak shape of the spectral peak to change the ridge slope includes: converting the ridge slope into a corresponding inclination angle, and confirming the inclination angle adjustment range according to the difference between the spectral line peak shape of the spectral peak and the inclination angle of the ideal spectral line peak shape of the spectral peak, adjusting the spectral line peak shape of the spectral peak in steps of 1°, and calculating the half-width at half height after each adjustment until the final half-width position is symmetrical with the spectral line peak shape on the other side. At this time, the ridge slope of the spectral line peak shape of the spectral peak is consistent with the ridge slope of the ideal spectral line peak shape.

4. A method for correcting the peak shape of a laser induced breakdown spectroscopy line according to claim 2, characterized in that: When calculating the ridge slope of the spectral peak shape and the spectral peak ideal spectral line peak shape, the intersection point from the spectral peak top to the corresponding peak shape and the peak height 5% is used as the endpoint for calculating the slope.

5. The method for correcting the peak shape of a laser induced breakdown spectroscopy line according to claim 1, characterized in that: Before fitting the original peak shape in step S02, the ridge line on the leading or trailing side is segmented using the nodes corresponding to the half-width position of the spectral peak of the original peak shape as the dividing points, and the ridge line slope from the half-width position to the peak top and the slope from the half-width position to the peak bottom of the spectrum line are calculated. The slope from the half-width position to the peak bottom is first modulated to be consistent with the ridge line slope from the half-width position to the peak top, and then the peak shape is fitted.

6. A laser induced breakdown spectrum tailing adaptive correction system, characterized in that: The laser induced breakdown spectrum is corrected using the correction method described in any one of claims 1 to 6.

7. An electronic device, characterized in that: The invention comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the program, a method for correcting the peak shape of a laser induced breakdown spectroscopy line as described in any one of claims 1 to 6 is implemented.

8. A computer-readable storage medium storing computer-executable instructions, characterized in that: The computer executable instructions are used to execute a method for correcting the peak shape of a laser induced breakdown spectroscopy line as described in any one of claims 1-6.

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