Method and system for detecting heavy metals in soil
By using reinforcement materials and laser-induced breakdown spectroscopy technology in soil samples, filtering preset element fingerprint peak areas and processing heavy metal fingerprint peak areas, the matrix effect problem of soil heavy metal detection in traditional technology is solved, and the accuracy of detection is improved and The signal strength enables more reliable measurement of heavy metal content.
Patent Information
- Application Number
- CN202411548101.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-01
- Publication Date
- 2024-12-27
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Traditional soil heavy metal detection technologies such as atomic absorption spectroscopy and ICP-MS require complex sample pretreatment and high equipment cost. Laser induced breakdown spectroscopy (LIBS) is affected by matrix effects when analyzing soil samples, resulting in inaccurate measurement results.
The soil samples were enhanced to varying degrees and then tabletted. Multiple spectra were obtained by laser-induced breakdown spectrum, preset element fingerprint peak areas were filtered, heavy metal fingerprint peak areas were processed to reduce matrix effects, and the predicted fit was obtained. The peak-to-peak value of the fingerprint of no reinforced heavy metals is calculated.
It improves the accuracy and signal strength of soil heavy metal detection, reduces the influence of matrix effects, reduces detection errors, and achieves a more reliable measurement of heavy metal content.
Smart Images
Figure CN119198255A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of environmental protection, and in particular to a method and system for detecting heavy metals in soil. Background Art
[0002] Soil is the basis of plant growth. Heavy metal pollution not only affects the yield and quality of crops, but may also endanger human health through the food chain. With the acceleration of industrialization and urbanization, the problem of heavy metal pollution has become more serious and has become an important environmental problem worldwide. Although traditional detection technologies such as atomic absorption spectrometry and inductively coupled plasma mass spectrometry (ICP-MS) have high sensitivity and accuracy, they often require complex sample pretreatment and have high equipment costs, which to a certain extent limits their widespread application in soil monitoring. Laser induced breakdown spectroscopy (LIBS), as an emerging analytical technology, has gradually been applied to soil heavy metal detection due to its rapid, non-destructive and real-time characteristics. However, when analyzing soil samples, LIBS spectroscopy is often affected by matrix effects, resulting in inaccurate results of heavy metal content determination. The use of enhancing materials can reduce the influence of matrix effects. The enhancing materials are to optimize the interaction between laser and sample, improve the intensity and quality of the signal, and thus reduce the influence of matrix effects. Although the enhancing materials increase the intensity of the heavy metal fingerprint peak in the spectrum, the enhancing effect and the proportion of the enhancing materials added are not a simple linear relationship. Inappropriate treatment methods will increase the error caused by the addition of enhancing materials. Summary of the invention
[0003] In a first aspect of the present invention, a method for detecting heavy metals in soil is provided, the method comprising: The soil samples are reinforced to different degrees by using reinforcing materials and then compressed to obtain a plurality of sample compressed tablets with different reinforcement degrees. A laser induced breakdown spectroscopy method is used to obtain a plurality of spectra at different positions of the sample compressed tablets. The area between two adjacent troughs closest to the heavy metal fingerprint peak and containing the fingerprint peak of the preset element is obtained to obtain the preset element fingerprint peak area. The plurality of spectra are filtered based on the preset element fingerprint peak area. The average value of the spectrum after filtering of the same sample tablet is used as the spectrum of the sample tablet, the spectrum of the sample tablet is processed according to the heavy metal fingerprint peak area in the spectrum, and the peak value corresponding to the predicted heavy metal fingerprint peak without enhancement is obtained; The heavy metal content in the soil is obtained using the peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced and the peak value of the heavy metal fingerprint peak area that is actually not enhanced.
[0004] In an optional embodiment, the filtering of multiple spectra based on the preset element fingerprint peak region is specifically: Calculate the similarity of the preset element fingerprint peak area corresponding to the same fingerprint peak of heavy metal; If the average similarity between the preset element fingerprint peak region and other preset element fingerprint peak regions is less than a threshold, the spectrum graph where the preset element fingerprint peak region is located is filtered out.
[0005] In an optional embodiment, the heavy metal fingerprint peak region is obtained by extracting the region between two adjacent troughs of the fingerprint peak containing the heavy metal in the spectrum of each sample compressed tablet.
[0006] In an optional embodiment, the spectrum of the sample tablet is processed according to the heavy metal fingerprint peak area in the spectrum, specifically: Obtaining the enhancement intensity of the sample tablet and all heavy metal fingerprint peak regions in the spectrum of the sample tablet, and constructing a triplet consisting of the enhancement intensity, the heavy metal fingerprint peak and the heavy metal fingerprint peak region; The ternary groups are divided into multiple groups according to the heavy metal fingerprint peaks, and the heavy metal fingerprint peaks of each group are the same; The peak value of the heavy metal fingerprint peak area of each triplet in the group is calculated, and the triplet corresponding to the abnormal peak value is deleted from the group.
[0007] In an optional embodiment, the peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced is specifically: For each group, the peak value is fitted according to the enhancement intensity, and the enhancement intensity is set to 0. The peak value corresponding to the predicted heavy metal fingerprint peak without enhancement is obtained through the fitting curve or straight line.
[0008] In a possible embodiment, the peak value corresponding to the predicted heavy metal fingerprint peak without enhancement and the peak value of the heavy metal fingerprint peak region without enhancement are used to obtain the heavy metal content in the soil, specifically: Calculate the average of the peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced and the peak value of the heavy metal fingerprint peak region that is actually not enhanced; The heavy metal content in the soil was obtained based on the average value.
[0009] In a second aspect of the present invention, a system for detecting heavy metals in soil is provided, the system comprising: A spectrum acquisition module is used to enhance soil samples to different degrees using an enhancement material and then compress the samples to obtain a plurality of sample compresses with different enhancement degrees, use a laser induced breakdown spectroscopy method to obtain a plurality of spectra at different positions of the sample compresses, obtain an area between two adjacent troughs of a fingerprint peak that is closest to a heavy metal fingerprint peak and contains a preset element, and obtain a preset element fingerprint peak area, and filter the plurality of spectra based on the preset element fingerprint peak area; A peak prediction module is used to take the average value of the spectrum after filtering of the same sample tablet as the spectrum of the sample tablet, process the spectrum of the sample tablet according to the heavy metal fingerprint peak area in the spectrum, and obtain the peak value corresponding to the predicted heavy metal fingerprint peak without enhancement; The heavy metal content calculation module is used to obtain the heavy metal content in the soil by using the peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced and the peak value of the heavy metal fingerprint peak area that is actually not enhanced.
[0010] In an optional embodiment, the filtering of multiple spectra based on the preset element fingerprint peak region is specifically: Calculate the similarity of the preset element fingerprint peak area corresponding to the same fingerprint peak of heavy metal; If the average similarity between the preset element fingerprint peak region and other preset element fingerprint peak regions is less than a threshold, the spectrum graph where the preset element fingerprint peak region is located is filtered out.
[0011] In an optional embodiment, the heavy metal fingerprint peak region is obtained by extracting the region between two adjacent troughs of the fingerprint peak containing the heavy metal in the spectrum of each sample compressed tablet.
[0012] In an optional embodiment, the spectrum of the sample tablet is processed according to the heavy metal fingerprint peak area in the spectrum, specifically: Obtaining the enhancement intensity of the sample tablet and all heavy metal fingerprint peak regions in the spectrum of the sample tablet, and constructing a triplet consisting of the enhancement intensity, the heavy metal fingerprint peak and the heavy metal fingerprint peak region; The ternary groups are divided into multiple groups according to the heavy metal fingerprint peaks, and the heavy metal fingerprint peaks of each group are the same; The peak value of the heavy metal fingerprint peak area of each triplet in the group is calculated, and the triplet corresponding to the abnormal peak value is deleted from the group.
[0013] In an optional embodiment, the peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced is specifically: For each group, the peak value is fitted according to the enhancement intensity, and the enhancement intensity is set to 0. The peak value corresponding to the predicted heavy metal fingerprint peak without enhancement is obtained through the fitting curve or straight line.
[0014] In a possible embodiment, the peak value corresponding to the predicted heavy metal fingerprint peak without enhancement and the peak value of the heavy metal fingerprint peak region without enhancement are used to obtain the heavy metal content in the soil, specifically: Calculate the average of the peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced and the peak value of the heavy metal fingerprint peak region that is actually not enhanced; The heavy metal content in the soil was obtained based on the average value.
[0015] In a third aspect of the present invention, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the method described in the first aspect is implemented.
[0016] In a fourth aspect of the present invention, a computer device is provided, the computer device comprising at least a readable storage medium and a processor, the readable storage medium storing a computer program, and the computer program, when executed by the processor, implements the method described in the first aspect.
[0017] In order to enhance the reliability and accuracy of the spectrum after adding the reinforcing material, the present invention first filters the spectrum according to the changes in the fingerprint peak area of the preset elements around the heavy metal fingerprint peak, and further processes the peak values of the fingerprint peak area of the same fingerprint peak to eliminate possible anomalies. Finally, multiple enhancement intensities and peak values of the fingerprint peak area are used for fitting to obtain the predicted peak value of the fingerprint peak area without enhancement, and the heavy metal content is obtained in combination with the peak value of the fingerprint peak area without enhancement actually measured. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is a flow chart of Embodiment 1; Figure 2 The schematic diagram of soil tablets with different soil qualities; Figure 3 is a schematic diagram of the spectrum; Figure 4 Schematic diagram of the preset element fingerprint peak area. DETAILED DESCRIPTION
[0019] The following is a description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, including various details of the embodiments of the present disclosure to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. Similarly, for the sake of clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description.
[0020] The first embodiment of the present invention provides a method for detecting heavy metals in soil. Figure 1 A flow chart of a first embodiment is shown, which includes: S1, using reinforcing materials to enhance soil samples to different degrees and then compressing them to obtain multiple sample compresses with different enhancement degrees, using laser induced breakdown spectroscopy to obtain multiple spectra at different positions of the sample compresses, obtaining the area between two adjacent troughs closest to the heavy metal fingerprint peak and containing the fingerprint peak of the preset element to obtain the preset element fingerprint peak area, and filtering the multiple spectra based on the preset element fingerprint peak area; Heavy metals in the soil directly affect the safety of crops, and then affect humans through crops. The heavy metals in the soil are mainly cadmium (Cd), arsenic (As), mercury (Hg), chromium (Cr), etc. In laser induced breakdown spectroscopy (LIBS) analysis, reinforcing materials help improve the sensitivity and accuracy of specific element detection. Reinforcing materials include but are not limited to KBr, KCl, C, Nano-ZnO, etc. In LIBS measurement, the soil sample is first enhanced to different degrees using the same reinforcing material, such as adding reinforcing materials of different amounts, and then each soil sample with enhanced strength is pressed into a tablet. The so-called tableting refers to compacting the soil sample into a sheet. Figure 2 The tabletting of a soil sample is shown. The specific process of tabletting is to crush or grind the soil into powder, dry the soil sample, and after drying to a certain degree, use a tabletting device to tablet, if the soil is reinforced with reinforcing materials, add a certain amount of reinforcing materials before crushing, and then stir and grind into powder.
[0021] For each sample tablet, the Laser-Induced Breakdown Spectroscopy (LIBS) method was used to obtain multiple spectra at different positions of the sample tablet. Multiple spectra were obtained for one sample tablet. Figure 3 A spectrum is shown. The spectrum of heavy metals is enhanced by reinforcing materials. Ideally, the intensity of the wavelength corresponding to the heavy metals will be greatly improved, while the improvement of other elements in the soil will be small or not obvious. If the intensity corresponding to the wavelengths of other elements is also greatly improved, it indicates that the currently collected spectrum is greatly affected by other factors, because the interference signal will affect the detection accuracy of heavy metals, resulting in increased errors, and it is not suitable as a spectrum for subsequent processing. The preset element fingerprint peak area is obtained by obtaining the area between two adjacent troughs that are closest to the fingerprint peak of the heavy metal and contain the fingerprint peak of the preset element. The preset element is an element with a high content in the soil, and the preset element is Ca, Si or Fe, etc. Assuming that the preset element is Ca, a fingerprint peak of the heavy metal Cr is 360.5nm. The area between the two adjacent troughs that are closest to the fingerprint peak 360.5nm and contain the Ca fingerprint peak is found as the fingerprint peak area of the preset element, that is, Ca. Figure 4The preset element fingerprint peak region is shown. The fingerprint peak region of the preset element closest to the heavy metal fingerprint peak is selected because after the reinforcing material enhances the heavy metal, the main change is the intensity of the wavelength near the heavy metal fingerprint peak. By finding the fingerprint peak region of the preset element closest to the heavy metal fingerprint peak, it can be more clearly seen whether the reinforcing material has an impact on the intensity of the wavelength close to it. Then, multiple spectra are filtered based on the preset element fingerprint peak region. In another alternative embodiment, the preset element fingerprint peak region is obtained by finding the fingerprint peak of the preset element closest to the heavy metal fingerprint peak, and then selecting an area of a preset length centered on the fingerprint peak of the preset element as the preset element fingerprint peak region. In one embodiment, the preset element is preselected.
[0022] In a specific embodiment, specifically: Calculate the similarity of the preset element fingerprint peak area corresponding to the same fingerprint peak of heavy metal; If the average similarity between the preset element fingerprint peak region and other preset element fingerprint peak regions is less than a threshold, the spectrum graph where the preset element fingerprint peak region is located is filtered out.
[0023] There are generally multiple fingerprint peaks of heavy metals. Each fingerprint peak in a spectrum graph will have a preset element fingerprint peak area. When there are multiple spectrum graphs, multiple preset element fingerprint peak areas will be obtained. For example, there are 3 sample tablets in total, and each sample tablet has 5 LIBS points, then there will be 15 spectra. For a fingerprint peak of heavy metal Cr, there will be 15 preset element fingerprint peak areas. The similarity of these 15 preset element fingerprint peak areas is calculated. If the similarity of a preset element fingerprint peak area and the average similarity of other preset element fingerprint peak areas is less than a threshold, the spectrum graph where the preset element fingerprint peak area is located is filtered out.
[0024] Each preset element fingerprint peak region is essentially a waveform. The similarity of the preset element fingerprint peak regions can be calculated by the similarity of the waveforms. The similarity calculation methods include but are not limited to Euclidean distance, normalized Euclidean distance, cross-correlation, normalized cross-correlation, etc. If the two fingerprint peak regions are of different sizes, the fingerprint peaks are aligned, and then the longer fingerprint peak region is intercepted to make the two fingerprint peak regions have the same range. If the average similarity of a preset element fingerprint peak region and other preset element fingerprint peak regions is small, it means that the spectrum graph where the preset element fingerprint peak region is located is greatly affected by the outside world, that is, the deviation is large, and the spectrum graph where the preset element fingerprint peak region is located is deleted.
[0025] S2, taking the average value of the spectrum after filtering of the same sample compressed tablet as the spectrum of the sample compressed tablet, processing the spectrum of the sample compressed tablet according to the heavy metal fingerprint peak area in the spectrum, and obtaining the peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced; The enhancement intensity of the same sample tablet is the same. After the above filtering, for all spectra from the same sample tablet, the average value of the spectrum is used as the spectrum of the sample tablet, where the average value of the spectrum refers to adding the intensities of the same wavelength and then calculating the average value as the intensity value of the same wavelength in the spectrum of the sample tablet.
[0026] In an optional embodiment, the spectrum of the sample tablet is further processed according to the heavy metal fingerprint peak area in the spectrum, and the processing method includes but is not limited to noise reduction processing.
[0027] In another optional embodiment, the spectrum of the sample tablet is processed according to the heavy metal fingerprint peak area in the spectrum, specifically: Obtaining the enhancement intensity of the sample tablet and all heavy metal fingerprint peak regions in the spectrum of the sample tablet, and constructing a triplet consisting of the enhancement intensity, the heavy metal fingerprint peak and the heavy metal fingerprint peak region; The ternary groups are divided into multiple groups according to the heavy metal fingerprint peaks, and the heavy metal fingerprint peaks of each group are the same; The peak value of the heavy metal fingerprint peak area of each triplet in the group is calculated, and the triplet corresponding to the abnormal peak value is deleted from the group.
[0028] Since there is more than one fingerprint peak of heavy metals, a fingerprint peak area is obtained for each fingerprint peak of heavy metals in the spectrum of the sample tablet, and the heavy metal fingerprint peak area is obtained by extracting the area between two adjacent troughs containing the fingerprint peak of heavy metals in the spectrum of each sample tablet. A triple of enhanced intensity, heavy metal fingerprint peak and heavy metal fingerprint peak area is constructed, and an exemplary triple is <enhanced intensity 1,360.5nm, fingerprint peak area 1>, <enhanced intensity 1,520.6nm, fingerprint peak area 2>. In another alternative embodiment, the heavy metal fingerprint peak area is centered on the heavy metal fingerprint peak, and an area of a preset length is selected as the heavy metal fingerprint peak area.
[0029] Then, the ternary groups of the same heavy metal fingerprint peaks are grouped together, and the fingerprint peaks in each group are the same, for example, <enhanced intensity 1, 360.5nm, fingerprint peak area 1> and <enhanced intensity 2, 360.5nm, fingerprint peak area 2> are a group, and the fingerprint peaks in this group are all 360.5nm.
[0030] For each group, calculate the peak value of the heavy metal fingerprint peak area of each triplet in the group. For example, the peak value of fingerprint peak area 1 is a1, and the peak value of fingerprint peak area 2 is a2. Delete the abnormal triplet from the group based on the peak value of the fingerprint peak area in the group. The greater the enhancement strength, the larger the peak value. One way to judge an abnormality is that if the enhancement strength in a triplet is large, but the peak value is small, then this peak value is regarded as an abnormal peak value. Another way to judge an abnormality is to use consistency detection to judge the abnormal peak value. Specifically, sort the triplets in the group in order of enhancement strength from small to large, and calculate the ratio of the peak difference and enhancement strength difference between the latter triplet and the former triplet, that is, calculate (b i+1 -b i ) / (a i+1 -a i ), b i is the peak value, a i To enhance the strength, if the ratio is negative or the ratio is not within the preset range, the peak corresponding to the latter triplet is taken as the abnormal peak.
[0031] Then, for each group, the peak value is fitted according to the enhancement intensity, and the enhancement intensity is set to 0. The peak value corresponding to the predicted heavy metal fingerprint peak without enhancement is obtained through the fitted curve or straight line. Among them, fitting the peak value according to the enhancement intensity is to construct a function or model, the input of the function or model is the enhancement intensity, and the output is the peak value. After obtaining the function or model, the enhancement intensity is set to 0 to obtain the peak value corresponding to the predicted heavy metal fingerprint peak without enhancement.
[0032] S3, obtaining the heavy metal content in the soil using the peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced and the peak value of the heavy metal fingerprint peak region that is actually not enhanced.
[0033] At the same time, when the soil is pressed, a pressed tablet without adding reinforcement materials will also be made. The spectrum of this pressed tablet is also obtained by LIBS. Then, the heavy metal content in the soil is obtained based on the peak value corresponding to the predicted heavy metal fingerprint peak without reinforcement and the peak value of the actual heavy metal fingerprint peak area without reinforcement. More specifically, Calculate the average of the peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced and the peak value of the heavy metal fingerprint peak region that is actually not enhanced; The heavy metal content in the soil was obtained based on the average value.
[0034] Each fingerprint peak of heavy metals will have an average value, which is actually the intensity value corresponding to the fingerprint peak. The heavy metal content is obtained through the pre-established relationship equation between the intensity value and the content. When there are multiple fingerprint peaks, the heavy metal content corresponding to each fingerprint peak of the same heavy metal will be obtained, and the average value of the heavy metal content corresponding to all fingerprint peaks will be used as the final content of heavy metals in the soil. For example, if there are two fingerprint peaks, the average value corresponding to the first fingerprint peak is v1, and the average value corresponding to the second fingerprint peak is v2. The heavy metal content corresponding to the average value v1 is s1, and the heavy metal content corresponding to the average value v2 is s2. The final content of heavy metals in the soil is the average value of s1 and s2.
[0035] A second embodiment of the present invention provides a system for detecting heavy metals in soil, the system comprising: A spectrum acquisition module is used to enhance soil samples to different degrees using an enhancement material and then compress the samples to obtain a plurality of sample compresses with different enhancement degrees, use a laser induced breakdown spectroscopy method to obtain a plurality of spectra at different positions of the sample compresses, obtain an area between two adjacent troughs of a fingerprint peak that is closest to a heavy metal fingerprint peak and contains a preset element, and obtain a preset element fingerprint peak area, and filter the plurality of spectra based on the preset element fingerprint peak area; A peak prediction module is used to take the average value of the spectrum after filtering of the same sample tablet as the spectrum of the sample tablet, process the spectrum of the sample tablet according to the heavy metal fingerprint peak area in the spectrum, and obtain the peak value corresponding to the predicted heavy metal fingerprint peak without enhancement; The heavy metal content calculation module is used to obtain the heavy metal content in the soil by using the peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced and the peak value of the heavy metal fingerprint peak area that is actually not enhanced.
[0036] In an optional embodiment, the filtering of multiple spectra based on the preset element fingerprint peak region is specifically: Calculate the similarity of the preset element fingerprint peak area corresponding to the same fingerprint peak of heavy metal; If the average similarity between the preset element fingerprint peak region and other preset element fingerprint peak regions is less than a threshold, the spectrum graph where the preset element fingerprint peak region is located is filtered out.
[0037] In an optional embodiment, the heavy metal fingerprint peak region is obtained by extracting the region between two adjacent troughs of the fingerprint peak containing the heavy metal in the spectrum of each sample compressed tablet.
[0038] In an optional embodiment, the spectrum of the sample tablet is processed according to the heavy metal fingerprint peak area in the spectrum, specifically: Obtaining the enhancement intensity of the sample tablet and all heavy metal fingerprint peak regions in the spectrum of the sample tablet, and constructing a triplet consisting of the enhancement intensity, the heavy metal fingerprint peak and the heavy metal fingerprint peak region; The ternary groups are divided into multiple groups according to the heavy metal fingerprint peaks, and the heavy metal fingerprint peaks of each group are the same; The peak value of the heavy metal fingerprint peak area of each triplet in the group is calculated, and the triplet corresponding to the abnormal peak value is deleted from the group.
[0039] In an optional embodiment, the peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced is specifically: For each group, the peak value is fitted according to the enhancement intensity, and the enhancement intensity is set to 0. The peak value corresponding to the predicted heavy metal fingerprint peak without enhancement is obtained through the fitting curve or straight line.
[0040] In a possible embodiment, the peak value corresponding to the predicted heavy metal fingerprint peak without enhancement and the peak value of the heavy metal fingerprint peak region without enhancement are used to obtain the heavy metal content in the soil, specifically: Calculate the average of the peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced and the peak value of the heavy metal fingerprint peak region that is actually not enhanced; The heavy metal content in the soil was obtained based on the average value.
[0041] A third embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the method described in the first embodiment is implemented.
[0042] A fourth embodiment of the present invention provides a computer device, which includes at least a readable storage medium and a processor, wherein a computer program is stored on the readable storage medium, and when the computer program is executed by the processor, the method described in the first embodiment is implemented.
[0043] The program code for implementing the method of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that the program code, when executed by the processor or controller, enables the functions / operations specified in the flow chart and / or block diagram to be implemented. The program code may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.
[0044] In the context of the present disclosure, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or device, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
[0045] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the computer. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).
[0046] The systems and techniques described herein may be implemented in a computing system that includes back-end components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes front-end components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such back-end components, middleware components, or front-end components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), and the Internet.
[0047] A computer system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The relationship between the client and the server is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. Among them, the server may be a cloud server, also known as a cloud computing server or a cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services ("Virtual Private Server", or "VPS" for short). The server may also be a server of a distributed system, or a server combined with a blockchain.
Claims
1. A method for detecting heavy metals in soil, characterized in that: The method comprises: The soil samples are reinforced to different degrees by using reinforcing materials and then compressed to obtain a plurality of sample compressed tablets with different reinforcement degrees. A laser induced breakdown spectroscopy method is used to obtain a plurality of spectra at different positions of the sample compressed tablets. The area between two adjacent troughs closest to the heavy metal fingerprint peak and containing the fingerprint peak of the preset element is obtained to obtain the preset element fingerprint peak area. The plurality of spectra are filtered based on the preset element fingerprint peak area. The average value of the spectrum after filtering of the same sample tablet is used as the spectrum of the sample tablet, the spectrum of the sample tablet is processed according to the heavy metal fingerprint peak area in the spectrum, and the peak value corresponding to the predicted heavy metal fingerprint peak without enhancement is obtained; The heavy metal content in the soil is obtained using the peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced and the peak value of the heavy metal fingerprint peak area that is actually not enhanced.
2. The method according to claim 1, characterized in that The filtering of multiple spectra based on the preset element fingerprint peak region is specifically as follows: Calculate the similarity of the preset element fingerprint peak area corresponding to the same fingerprint peak of heavy metal; If the average similarity between the preset element fingerprint peak region and other preset element fingerprint peak regions is less than a threshold, the spectrum graph where the preset element fingerprint peak region is located is filtered out.
3. The method according to claim 1, characterized in that The heavy metal fingerprint peak region is obtained by extracting the region between two adjacent troughs of the fingerprint peak containing the heavy metal in the spectrum of each sample compressed tablet.
4. The method according to claim 1, characterized in that The processing of the spectrum of the sample tablet according to the heavy metal fingerprint peak area in the spectrum is specifically as follows: Obtaining the enhancement intensity of the sample tablet and all heavy metal fingerprint peak regions in the spectrum of the sample tablet, and constructing a triplet consisting of the enhancement intensity, the heavy metal fingerprint peak and the heavy metal fingerprint peak region; The ternary groups are divided into multiple groups according to the heavy metal fingerprint peaks, and the heavy metal fingerprint peaks of each group are the same; The peak value of the heavy metal fingerprint peak area of each triplet in the group is calculated, and the triplet corresponding to the abnormal peak value is deleted from the group.
5. The method according to claim 4, characterized in that The peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced is specifically: For each group, the peak value is fitted according to the enhancement intensity, and the enhancement intensity is set to 0. The peak value corresponding to the predicted heavy metal fingerprint peak without enhancement is obtained through the fitting curve or straight line.
6. The method according to any one of claims 1 to 5, characterized in that: The heavy metal content in the soil is obtained by using the peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced and the peak value of the heavy metal fingerprint peak area that is not enhanced, specifically: Calculate the average of the peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced and the peak value of the heavy metal fingerprint peak region that is actually not enhanced; The heavy metal content in the soil was obtained based on the average value.
7. A heavy metal detection system in soil, characterized in that: The system comprises: A spectrum acquisition module is used to enhance soil samples to different degrees using an enhancement material and then compress the samples to obtain a plurality of sample compresses with different enhancement degrees, use a laser induced breakdown spectroscopy method to obtain a plurality of spectra at different positions of the sample compresses, obtain an area between two adjacent troughs of a fingerprint peak that is closest to a heavy metal fingerprint peak and contains a preset element, and obtain a preset element fingerprint peak area, and filter the plurality of spectra based on the preset element fingerprint peak area; A peak prediction module is used to take the average value of the spectrum after filtering of the same sample tablet as the spectrum of the sample tablet, process the spectrum of the sample tablet according to the heavy metal fingerprint peak area in the spectrum, and obtain the peak value corresponding to the predicted heavy metal fingerprint peak without enhancement; The heavy metal content calculation module is used to obtain the heavy metal content in the soil by using the peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced and the peak value of the heavy metal fingerprint peak area that is actually not enhanced.
8. The system according to claim 7, characterized in that The filtering of multiple spectra based on the preset element fingerprint peak region is specifically as follows: Calculate the similarity of the preset element fingerprint peak area corresponding to the same fingerprint peak of heavy metal; If the average similarity between the preset element fingerprint peak region and other preset element fingerprint peak regions is less than a threshold, the spectrum graph where the preset element fingerprint peak region is located is filtered out.
9. The system according to claim 7, characterized in that The processing of the spectrum of the sample tablet according to the heavy metal fingerprint peak area in the spectrum is specifically as follows: Obtaining the enhancement intensity of the sample tablet and all heavy metal fingerprint peak regions in the spectrum of the sample tablet, and constructing a triplet consisting of the enhancement intensity, the heavy metal fingerprint peak and the heavy metal fingerprint peak region; The ternary groups are divided into multiple groups according to the heavy metal fingerprint peaks, and the heavy metal fingerprint peaks of each group are the same; The peak value of the heavy metal fingerprint peak area of each triplet in the group is calculated, and the triplet corresponding to the abnormal peak value is deleted from the group.
10. The system according to claim 9, characterized in that The peak value corresponding to the predicted heavy metal fingerprint peak that is not enhanced is specifically: For each group, the peak value is fitted according to the enhancement intensity, and the enhancement intensity is set to 0. The peak value corresponding to the predicted heavy metal fingerprint peak without enhancement is obtained through the fitting curve or straight line.