A laser gas detection method and system

Abstract

This invention provides a laser gas detection method and system. The method includes: pre-establishing a relationship model among gas concentration, ambient temperature parameter, and absorption pit area parameter; determining the real-time ambient temperature parameter and the real-time absorption pit area parameter; and calculating the real-time gas concentration using the relationship model based on the real-time ambient temperature parameter and the real-time absorption pit area parameter. The system includes a relationship model management module, a temperature parameter determination module, an area parameter determination module, and a gas concentration calculation module. The relationship model management module is used to pre-establish the relationship model; the temperature parameter determination module is used to determine the real-time ambient temperature parameter; the area parameter determination module is used to determine the real-time absorption pit area parameter; and the gas concentration calculation module is used to calculate the real-time gas concentration using the relationship model based on the real-time ambient temperature parameter and the real-time absorption pit area parameter. Therefore, this invention has the advantages of fast response and high detection accuracy.

Description

Technical Field

[0001] This invention relates to the field of gas detection technology, and more specifically, to a laser gas detection method and system. Background Technology

[0002] In recent years, laser gas sensing technology has become a hot topic in the field of gas detection. Compared with traditional non-laser sensing technologies, laser gas detection methods have advantages such as high sensitivity, high detection accuracy, good operational stability, resistance to external interference, and good environmental adaptability. Laser gas sensing technology utilizes the principle of laser spectroscopy to detect gas concentrations, etc. Tunable Diode Laser Absorption Spectroscopy (TDLAS) is a gas concentration measurement technique based on laser spectroscopy and is one of the most widely used methods in laser sensing technology.

[0003] To achieve high-precision detection of laser-generated gases, a common method is to adjust the absorption pits in the main path signal to a fixed position in real time by adjusting the laser's operating temperature after demodulating the reference detector signal through the reference gas chamber. However, this method suffers from problems such as inaccurate laser operating temperature adjustment due to circuit noise and optical path noise, leading to large detection errors and slow response.

[0004] Therefore, it is essential to design a laser gas detection method that does not require adjustment of the laser's operating temperature and is more versatile.

[0005] In order to solve the above problems, people have been seeking an ideal technological solution. Summary of the Invention

[0006] Therefore, it is necessary to provide a laser gas detection method and system to address the above-mentioned technical problems. During gas detection, the laser operating temperature does not need to be changed, and the real-time gas concentration value can be calculated quickly and accurately using the aforementioned relationship model.

[0007] To achieve the above objectives, the first aspect of the present invention provides a laser gas detection method, comprising: pre-establishing a relationship model among gas concentration, ambient temperature parameter, and absorption pit area parameter; wherein, the relationship model is expressed as: y=(a×x 2 +b×x+c)×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, z represents the obtained absorption pit area parameter when there is gas; a represents the first relationship coefficient, b represents the second relationship coefficient, and c represents the third relationship coefficient;

[0008] Determine the real-time ambient temperature parameters and the real-time absorption pit area parameters; wherein, the real-time ambient temperature parameters refer to parameters related to the real-time temperature around the laser;

[0009] The real-time gas concentration is calculated using the relationship model based on the real-time ambient temperature parameter and the real-time absorption pit area parameter.

[0010] To achieve the above objectives, a second aspect of the present invention provides another laser gas detection method, comprising: pre-establishing a relationship model among gas concentration, ambient temperature parameter, and absorption pit depth parameter; wherein, the relationship model is expressed as: y=(a×x 2 +b×x+c)×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, z represents the obtained absorption pit depth parameter when there is gas; a represents the first relationship coefficient, b represents the second relationship coefficient, and c represents the third relationship coefficient;

[0011] Determine the real-time ambient temperature parameters and the real-time absorption pit depth parameters; wherein, the real-time ambient temperature parameters refer to parameters related to the real-time temperature around the laser;

[0012] The real-time gas concentration is calculated using the relationship model based on the real-time ambient temperature parameter and the real-time absorption pit depth parameter.

[0013] To achieve the above objectives, a third aspect of the present invention provides another laser gas detection method, comprising: pre-establishing a relationship model among gas concentration, ambient temperature parameters, and harmonic parameters; wherein, the relationship model is expressed as: y=(a×x 2 +b×x+c)×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, z represents the obtained harmonic parameter when there is gas; a represents the first relation coefficient, b represents the second relation coefficient, and c represents the third relation coefficient;

[0014] Determine the real-time ambient temperature parameters and real-time harmonic parameters; wherein, the real-time ambient temperature parameters refer to parameters related to the real-time temperature around the laser, and the harmonic parameters refer to the second harmonic amplitude V. 2f With the amplitude V of the first harmonic 1f The ratio;

[0015] The real-time gas concentration is calculated using the relationship model based on the real-time ambient temperature parameters and the real-time harmonic parameters.

[0016] To achieve the above objectives, a fourth aspect of the present invention provides a laser gas detection system, comprising a relational model management module, a temperature parameter determination module, an area parameter determination module, and a gas concentration calculation module, wherein...

[0017] The relational model management module is used to pre-establish a relational model among gas concentration, ambient temperature parameters, and absorption pit area parameters; wherein, the relational model is expressed as: y=(a×x 2 +b×x+c)×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, z represents the obtained absorption pit area parameter when there is gas; a represents the first relationship coefficient, b represents the second relationship coefficient, and c represents the third relationship coefficient;

[0018] The temperature parameter determination module is used to determine the real-time ambient temperature parameter; wherein, the real-time ambient temperature parameter refers to the parameter related to the real-time temperature around the laser.

[0019] The area parameter determination module is used to determine the real-time absorption pit area parameters;

[0020] The gas concentration calculation module is used to calculate the real-time gas concentration based on the real-time ambient temperature parameter and the real-time absorption pit area parameter using the relationship model.

[0021] To achieve the above objectives, a fifth aspect of the present invention provides another laser gas detection system, comprising a relational model management module, a temperature parameter determination module, a depth parameter determination module, and a gas concentration calculation module, wherein...

[0022] The relational model management module is used to pre-establish a relational model among gas concentration, ambient temperature parameters, and absorption pit depth parameters; wherein, the relational model is expressed as: y=(a×x 2 +b×x+c)×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, z represents the obtained absorption pit depth parameter when there is gas; a represents the first relationship coefficient, b represents the second relationship coefficient, and c represents the third relationship coefficient;

[0023] The temperature parameter determination module is used to determine the real-time ambient temperature parameter; wherein, the real-time ambient temperature parameter refers to the parameter related to the real-time temperature around the laser.

[0024] The depth parameter determination module is used to determine the real-time absorption pit depth parameter;

[0025] The gas concentration calculation module is used to calculate the real-time gas concentration based on the real-time ambient temperature parameter and the real-time absorption pit depth parameter using the relationship model.

[0026] To achieve the above objectives, a sixth aspect of the present invention provides another laser gas detection system, which includes a relational model management module, a temperature parameter determination module, a harmonic parameter determination module, and a gas concentration calculation module, wherein...

[0027] The relational model management module is used to pre-establish a relational model among gas concentration, ambient temperature parameters, and harmonic parameters; wherein, the relational model is expressed as: y=(a×x 2 +b×x+c)×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, z represents the obtained harmonic parameter when there is gas; a represents the first relation coefficient, b represents the second relation coefficient, and c represents the third relation coefficient;

[0028] The temperature parameter determination module is used to determine the real-time ambient temperature parameter; wherein, the real-time ambient temperature parameter refers to the parameter related to the real-time temperature around the laser.

[0029] The harmonic parameter determination module is used to determine real-time harmonic parameters; wherein, the harmonic parameter refers to the second harmonic amplitude V. 2f With the amplitude V of the first harmonic 1f The ratio;

[0030] The gas concentration calculation module is used to calculate the real-time gas concentration based on the real-time ambient temperature parameter and the real-time harmonic parameter using the relationship model.

[0031] To achieve the above objectives, a seventh aspect of the present invention provides a computer device comprising a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus; the memory is used to store computer programs; and the processor, when executing the program stored in the memory, implements the laser gas detection method as described above.

[0032] To achieve the above objectives, an eighth aspect of the present invention provides a readable storage medium having instructions stored thereon that, when executed by one or more processors, cause the processors to perform the laser gas detection method as described above.

[0033] The beneficial effects of this invention are as follows:

[0034] 1) This invention establishes a relationship model between gas concentration, ambient temperature parameters, and absorption pit area parameters in advance. During gas detection, the real-time gas concentration value can be quickly and accurately calculated using the relationship model based on the real-time ambient temperature parameters and the real-time absorption pit area parameters. This invention does not require changing the position of the absorption pit through the laser operating temperature, nor does it require temperature compensation for the obtained real-time gas concentration value. It has the advantages of fast response and high detection accuracy.

[0035] 2) By pre-establishing a relationship model among gas concentration, ambient temperature parameters, and absorption pit depth parameters, this invention can quickly and accurately calculate the real-time gas concentration value based on the real-time ambient temperature parameters and the real-time absorption pit depth parameters during gas detection. This invention does not require changing the position of the absorption pit through the laser's operating temperature, nor does it require temperature compensation for the obtained real-time gas concentration value.

[0036] 3) By pre-establishing a relationship model among gas concentration, ambient temperature parameters, and harmonic parameters, this invention can quickly and accurately calculate the real-time gas concentration value based on the real-time ambient temperature parameters and real-time harmonic parameters during gas detection. This invention does not require changing the position of the absorption pit by adjusting the laser operating temperature, nor does it require temperature compensation for the obtained real-time gas concentration value. Attached Figure Description

[0037] Figure 1 This is a schematic flowchart of the laser gas detection method in Embodiment 1 of the present invention;

[0038] Figure 2 This is a schematic diagram of the normalized waveform of light intensity according to the present invention;

[0039] Figure 3 This is a schematic diagram of the start and end points of the absorption pits in the normalized waveform diagram of the light intensity of this invention.

[0040] Figure 4 This is a schematic diagram of the absorption pit depth parameter A in the normalized waveform diagram of the light intensity of the present invention;

[0041] Figure 5 This is a schematic diagram of the laser gas detection system of the present invention. Figure 1 ;

[0042] Figure 6 This is a schematic diagram of the laser gas detection system of the present invention. Figure 2 ;

[0043] Figure 7 This is a schematic diagram of the laser gas detection system of the present invention. Figure 3 ;

[0044] Figure 8 This is a schematic diagram of the hardware structure of the laser gas detection system of the present invention. Detailed Implementation

[0045] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0046] To facilitate understanding, the interactive parties and / or terms and / or custom terms involved in this invention will first be explained in conjunction with the technical solution of this invention:

[0047] Absorption pit: In a TDLAS system, each gas molecule has its own specific absorption spectral line. When the laser wavelength scans across these spectral lines, the gas molecules absorb the laser light with a frequency that matches the center frequency of their absorption spectral line, resulting in a decrease in laser intensity. This region of intensity decrease appears as a "pit" or "valley" on the spectrum, known as an "absorption pit".

[0048] The relational model refers to the relationship between gas concentration, ambient temperature parameters, and absorption pit parameters. The absorption pit parameters can be absorption pit area parameters, absorption pit depth parameters, or harmonic parameters. When establishing the relational model, the gas concentration refers to the concentration of the introduced standard gas. The gas concentration calculated using the relational model is the gas concentration after temperature compensation. The ambient temperature parameter refers to the AD value corresponding to the thermistor (this AD value refers to the parameter value obtained after the thermistor output value has been converted by existing signal conditioning circuits and ADC (Analog-to-Digital Converter) circuits).

[0049] It should be noted that this invention establishes a relationship model between gas concentration, ambient temperature parameters, and absorption pit parameters in advance. During gas detection, the real-time gas concentration value can be quickly and accurately calculated using the relationship model based on the real-time ambient temperature parameters and real-time absorption pit parameters. This invention does not require changing the position of the absorption pit through the laser's operating temperature, nor does it require temperature compensation for the obtained real-time gas concentration value. This not only simplifies the hardware of laser gas detection but also improves the response speed.

[0050] Laser gas detection system: includes software and hardware components; the software components are attached. Figure 5 As shown in Figures 6 or 7, the hardware component refers to the laser control board. This board includes the laser, a temperature control unit (used to maintain the laser at a constant temperature, such as 25°C), a detector, a signal filtering and amplification unit, an MCU unit, a temperature sensing element (detecting ambient temperature via a thermistor), and a gas chamber, as shown in the attached figure. Figure 8 As shown.

[0051] Example 1

[0052] As attached Figure 1 As shown in the figure, this embodiment provides a specific implementation method for laser gas detection;

[0053] The laser gas detection method includes:

[0054] A relationship model is pre-established among gas concentration, ambient temperature, and absorption pit area; wherein, the relationship model is expressed as: y=(a×x 2+b×x+c)×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, z represents the obtained absorption pit area parameter when there is gas; a represents the first relationship coefficient, b represents the second relationship coefficient, and c represents the third relationship coefficient;

[0055] Determine the real-time ambient temperature parameters and the real-time absorption pit area parameters; wherein, the real-time ambient temperature parameters refer to parameters related to the real-time temperature around the laser;

[0056] The real-time gas concentration is calculated using the relationship model based on the real-time ambient temperature parameter and the real-time absorption pit area parameter.

[0057] It should be noted that this invention establishes a relationship model between gas concentration, ambient temperature parameters, and absorption pit area parameters in advance. During gas detection, the real-time gas concentration value can be quickly and accurately calculated using the relationship model based on the real-time ambient temperature parameters and the real-time absorption pit area parameters. This invention does not require changing the position of the absorption pit through the laser's operating temperature, nor does it require temperature compensation for the obtained real-time gas concentration value. It has the advantages of fast response, high detection accuracy, and simple calculation method.

[0058] It should also be noted that the absorption pit area parameter refers to the area of ​​the region enclosed by the light intensity waveform between the start and end points of the absorption pit and the baseline in the normalized light intensity waveform diagram, with the normalized value on the baseline being 1. Specifically, after normalizing the acquired detector signal, the logarithm of some or all signal points can be calculated and then accumulated to obtain the absorption pit area parameter.

[0059] In some embodiments, when determining the real-time absorption pit area parameter, the following is performed:

[0060] The collected detector signals are normalized to obtain the corresponding normalized light intensity waveform.

[0061] Based on the normalized waveform of the light intensity, determine the starting point and the ending point of the absorption pit.

[0062] First, the logarithm of the normalized value corresponding to the starting point of the absorption pit is calculated, then the logarithm of the normalized value corresponding to the ending point of the absorption pit is calculated, and finally the logarithm of each normalized value between the starting point and the ending point of the absorption pit is calculated. The logarithmic results are then accumulated and used as the real-time absorption pit area parameter.

[0063] Wherein, the real-time absorption pit area parameter = ln(F i )+…+ln(F j ), F i F represents the normalized value corresponding to the starting point of the absorption pit. jThe normalized value represents the endpoint of the absorption pit; the normalized value = first signal value / second signal value, where the first signal value refers to the ADC sample value obtained after amplification, filtering and ADC conversion of the electrical signal output by the detector when there is no target gas, and the second signal value refers to the ADC sample value obtained after amplification, filtering and ADC conversion of the electrical signal output by the detector when there is target gas.

[0064] It should be noted that the normalization process in this embodiment refers to the ratio of the intensity-dependent ADC sample value output by the laser to the intensity-dependent ADC sample value received by the detector. Its function is to eliminate or reduce signal fluctuations caused by factors such as ambient light and device aging, and to simplify the subsequent processing flow, thereby improving the accuracy and reliability of the measurement.

[0065] It should also be noted that this embodiment uses the slope of the waveform to determine the start and end points of the absorption pit. The calculation method of the slope corresponding to each sampling point is existing technology and will not be described in detail here. When the slope corresponding to a certain sampling point is greater than a preset rising threshold, the corresponding sampling point is taken as the start point of the absorption pit. When the slope corresponding to a certain sampling point is less than a preset falling threshold, the corresponding sampling point is taken as the end point of the absorption pit.

[0066] It should also be noted that the light intensity normalized waveform refers to the waveform obtained after normalizing the detector signal, as shown in the attached figure. Figure 2 As shown; Figure 2 The horizontal axis represents the number of sampling points. Figure 2 The vertical axis represents the normalized value.

[0067] In one specific implementation, as shown in the appendix Figure 3 As shown, the baseline is a horizontal line with a normalized value of 1. The starting point of the absorption pit is N78 (the 78th sampling point), and the ending point is N199 (the 199th sampling point). The area enclosed by the light intensity waveform between the starting and ending points of the absorption pit and the baseline in the normalized light intensity waveform diagram is the attached area. Figure 3 The area enclosed by the red baseline and the blue waveform.

[0068] It should also be noted that in a TDLAS system, when the laser wavelength scans across the absorption lines of gas molecules, a decrease in laser intensity occurs; this region of intensity decrease is related to the surrounding area. Figure 3 The area enclosed by the red baseline and the blue waveform corresponds to each other.

[0069] Based on the above-described laser gas detection method, this embodiment also provides a specific implementation of a laser gas detection system, as shown in the appendix. Figure 5As shown; the solution provided by this system is similar to the solution described in the above method. Therefore, the specific limitations of one or more laser gas detection system embodiments provided below can be found in the limitations of the laser gas detection method above, and will not be repeated here.

[0070] Specifically, the laser gas detection system includes a relationship model management module, a temperature parameter determination module, an area parameter determination module, and a gas concentration calculation module, wherein...

[0071] The relational model management module is used to pre-establish a relational model among gas concentration, ambient temperature parameters, and absorption pit area parameters; wherein, the relational model is expressed as: y=(a×x 2 +b×x+c)×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, z represents the obtained absorption pit area parameter when there is gas; a represents the first relationship coefficient, b represents the second relationship coefficient, and c represents the third relationship coefficient;

[0072] The temperature parameter determination module is used to determine the real-time ambient temperature parameter; wherein, the real-time ambient temperature parameter refers to the parameter related to the real-time temperature around the laser.

[0073] The area parameter determination module is used to determine the real-time absorption pit area parameters;

[0074] The gas concentration calculation module is used to calculate the real-time gas concentration based on the real-time ambient temperature parameter and the real-time absorption pit area parameter using the relationship model.

[0075] In some embodiments, when the area parameter determination module determines the real-time absorption pit area parameter, it performs the following:

[0076] The collected detector signals are normalized to obtain the corresponding normalized light intensity waveform.

[0077] Based on the normalized waveform of the light intensity, determine the starting point and the ending point of the absorption pit.

[0078] First, the logarithm of the normalized value corresponding to the starting point of the absorption pit is calculated, then the logarithm of the normalized value corresponding to the ending point of the absorption pit is calculated, and finally the logarithm of each normalized value between the starting point and the ending point of the absorption pit is calculated. The logarithmic results are then accumulated and used as the real-time absorption pit area parameter.

[0079] Wherein, the real-time absorption pit area parameter = ln(F i )+…+ln(F j ), F i F represents the normalized value corresponding to the starting point of the absorption pit. jThe normalized value represents the endpoint of the absorption pit; the normalized value = first signal value / second signal value, where the first signal value refers to the ADC sample value obtained after amplification, filtering and ADC conversion of the electrical signal output by the detector when there is no target gas, and the second signal value refers to the ADC sample value obtained after amplification, filtering and ADC conversion of the electrical signal output by the detector when there is target gas.

[0080] In one specific implementation, when pre-establishing a relationship model among gas concentration, ambient temperature parameters, and absorption pit depth parameters, the following steps are performed:

[0081] (1) Determine the laser's current scanning range (e.g., 20-70mA) and target operating temperature (e.g., 25℃) according to the laser's datasheet;

[0082] Under normal temperature conditions, the gas absorption pit is positioned at the center of the laser scanning current;

[0083] (2) High and low temperature ventilation test was conducted using an annular gas box, a gas mixing instrument and standard gas. At room temperature of 25℃, standard gas of different concentrations was introduced as needed.

[0084] Record the set temperature of the annular gas chamber, the ambient temperature parameters measured on the laser control board, the absorption pit area parameters, and the concentration of the standard gas introduced.

[0085] (3) Change the set temperature of the annular gas chamber every 10°C and record the set temperature of different annular gas chambers, the ambient temperature parameters measured on the laser control board, the absorption pit area parameters and the concentration of the standard gas introduced.

[0086] As shown in the table below:

[0087]

[0088] (4) Based on the ambient temperature parameters, absorption pit parameters and gas concentration (the concentration of the standard gas introduced) recorded in the table above, establish a relationship model among the gas concentration (the concentration of the standard gas introduced), ambient temperature parameters and absorption pit area parameters.

[0089] In one specific implementation, the first relationship coefficient a in the relationship model established among the gas concentration (the concentration of the standard gas introduced), the ambient temperature parameter, and the absorption pit area parameter is -0.000000490285536, the second relationship coefficient b is -0.000136911272407, and the third relationship coefficient c is -0.020805114086763.

[0090] It should be noted that by pre-establishing a relationship model among gas concentration, ambient temperature parameters, and absorption pit area parameters, this invention eliminates the need to change the laser's operating temperature during gas detection. Based on real-time ambient temperature parameters and real-time absorption pit parameters, the target gas concentration can be quickly and accurately calculated using the relationship model among gas concentration, ambient temperature parameters, and absorption pit area parameters.

[0091] It should also be noted that since the relationship model is established based on the concentration of the introduced standard gas, which is known and accurate, the relationship model is equivalent to being established based on the gas concentration after temperature compensation. Therefore, this invention does not need to perform temperature compensation on the obtained real-time gas concentration value, and can also eliminate the influence of ambient temperature on gas concentration.

[0092] Example 2

[0093] This embodiment provides another specific implementation of the laser gas detection method. The main difference between this embodiment and embodiment 1 is that the relationship model is established using the absorption pit depth parameter. When calculating the gas concentration, it is necessary to determine the real-time absorption pit depth parameter.

[0094] In some embodiments, the laser gas detection method includes:

[0095] A relationship model is pre-established among gas concentration, ambient temperature, and absorption pit depth; wherein, the relationship model is expressed as: y=(a×x 2 +b×x+c)×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, z represents the obtained absorption pit depth parameter when there is gas; a represents the first relationship coefficient, b represents the second relationship coefficient, and c represents the third relationship coefficient;

[0096] Determine the real-time ambient temperature parameters and the real-time absorption pit depth parameters; wherein, the real-time ambient temperature parameters refer to parameters related to the real-time temperature around the laser;

[0097] The real-time gas concentration is calculated using the relationship model based on the real-time ambient temperature parameter and the real-time absorption pit depth parameter.

[0098] It should be noted that this invention establishes a relationship model between gas concentration, ambient temperature parameters, and absorption pit depth parameters in advance. During gas detection, the real-time gas concentration value can be quickly and accurately calculated using the relationship model based on the real-time ambient temperature parameters and the real-time absorption pit depth parameters. This invention does not require changing the position of the absorption pit through the laser's operating temperature, nor does it require temperature compensation for the obtained real-time gas concentration value. It has the advantages of fast response, high detection accuracy, and simple calculation method.

[0099] It should also be noted that the absorption pit depth parameter refers to the parameter corresponding to the difference between the maximum normalized value of light intensity and the reference value in the normalized light intensity waveform, and the normalized value corresponding to the reference value is 1.

[0100] In some embodiments, when determining the real-time absorption pit depth parameter, the following is performed:

[0101] The collected detector signals are normalized to obtain the corresponding normalized light intensity waveform.

[0102] Based on the normalized light intensity waveform, the depth parameter A is determined; wherein, the depth parameter A refers to the maximum value of the normalized value between the start and end points of the absorption pit;

[0103] Based on the depth parameter A, the real-time absorption pit depth parameter is calculated; wherein, the real-time absorption pit depth parameter = ln(A).

[0104] It should be noted that the normalization processing steps described above are consistent with those in Example 1, and will not be repeated here. The light intensity normalized waveform refers to the waveform obtained after normalizing the detector signal, as shown in the attached figure. Figure 2 As shown; Figure 2 The horizontal axis represents the number of sampling points. Figure 2 The vertical axis represents the normalized value.

[0105] As attached Figure 4 As shown, A represents the depth parameter. Figure 4 In the normalized waveform diagram of light intensity, the maximum normalized value of light intensity is 1.05, and the reference value is 1. Then A = 1.05 - 1 = 0.05, and the real-time absorption pit depth parameter = ln(A) = ln(0.05).

[0106] Based on the above-described laser gas detection method, this embodiment also provides a specific implementation of a laser gas detection system, as shown in the appendix. Figure 6 As shown;

[0107] The laser gas detection system includes a relational model management module, a temperature parameter determination module, a depth parameter determination module, and a gas concentration calculation module.

[0108] The relational model management module is used to pre-establish a relational model among gas concentration, ambient temperature parameters, and absorption pit depth parameters; wherein, the relational model is expressed as: y=(a×x 2 +b×x+c)×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, z represents the obtained absorption pit depth parameter when there is gas; a represents the first relationship coefficient, b represents the second relationship coefficient, and c represents the third relationship coefficient;

[0109] The temperature parameter determination module is used to determine the real-time ambient temperature parameter; wherein, the real-time ambient temperature parameter refers to the parameter related to the real-time temperature around the laser.

[0110] The depth parameter determination module is used to determine the real-time absorption pit depth parameter;

[0111] The gas concentration calculation module is used to calculate the real-time gas concentration based on the real-time ambient temperature parameter and the real-time absorption pit depth parameter using the relationship model.

[0112] In some embodiments, when the depth parameter determination module determines the real-time absorption pit depth parameter, it performs the following:

[0113] The collected detector signals are normalized to obtain the corresponding normalized light intensity waveform.

[0114] Based on the normalized light intensity waveform, the depth parameter A is determined; wherein, the depth parameter A refers to the maximum value of the normalized value between the start and end points of the absorption pit;

[0115] Based on the depth parameter A, the real-time absorption pit depth parameter is calculated; wherein, the real-time absorption pit depth parameter = ln(A).

[0116] It should be noted that the common practice of laser gas detection systems is as follows: after the scanning current of the laser is determined, the operating temperature of the laser is generally changed so that the position of the absorption pit when the scanning current appears in the presence of gas is a fixed position (such as the middle position). Then, regardless of whether the external temperature changes, once the position of the absorption pit is found to deviate from the middle position, the operating temperature of the laser is changed so that the absorption pit position reappears at the middle position of the scanning current.

[0117] However, before calculating the gas concentration value, this invention establishes a relationship model between the gas concentration, ambient temperature parameter, and absorption pit depth parameter. During gas detection, the real-time gas concentration value can be quickly and accurately calculated using the relationship model based on the real-time ambient temperature parameter and the real-time absorption pit depth parameter, without changing the laser operating temperature. This eliminates the need to change the laser operating temperature and avoids gas detection errors caused by inaccurate gas absorption pit position adjustment due to circuit noise and optical path noise.

[0118] Example 3

[0119] This embodiment provides another specific implementation of the laser gas detection method. The main difference between this embodiment and the above embodiment is that the relationship model is established using harmonic parameters. When calculating the gas concentration, it is necessary to determine the real-time harmonic parameters.

[0120] In some embodiments, the laser gas detection method includes:

[0121] A relationship model is pre-established among gas concentration, ambient temperature parameters, and harmonic parameters; wherein, the relationship model is expressed as: y=(a×x 2 +b×x+c)×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, z represents the obtained harmonic parameter when there is gas; a represents the first relation coefficient, b represents the second relation coefficient, and c represents the third relation coefficient;

[0122] Determine the real-time ambient temperature parameters and real-time harmonic parameters; wherein, the real-time ambient temperature parameters refer to parameters related to the real-time temperature around the laser, and the harmonic parameters refer to the second harmonic amplitude V. 2f With the amplitude V of the first harmonic 1f The ratio;

[0123] The real-time gas concentration is calculated using the relationship model based on the real-time ambient temperature parameters and the real-time harmonic parameters.

[0124] Based on the above-described laser gas detection method, this embodiment also provides a specific implementation of a laser gas detection system, as shown in the appendix. Figure 7 As shown;

[0125] The laser gas detection system includes a relational model management module, a temperature parameter determination module, a harmonic parameter determination module, and a gas concentration calculation module, wherein...

[0126] The relational model management module is used to pre-establish a relational model among gas concentration, ambient temperature parameters, and harmonic parameters; wherein, the relational model is expressed as: y=(a×x 2 +b×x+c)×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, z represents the obtained harmonic parameter when there is gas; a represents the first relation coefficient, b represents the second relation coefficient, and c represents the third relation coefficient;

[0127] The temperature parameter determination module is used to determine the real-time ambient temperature parameter; wherein, the real-time ambient temperature parameter refers to the parameter related to the real-time temperature around the laser.

[0128] The harmonic parameter determination module is used to determine real-time harmonic parameters; wherein, the harmonic parameter refers to the second harmonic amplitude V. 2f With the amplitude V of the first harmonic 1f The ratio;

[0129] The gas concentration calculation module is used to calculate the real-time gas concentration based on the real-time ambient temperature parameter and the real-time harmonic parameter using the relationship model.

[0130] It should be noted that this invention establishes a relationship model between gas concentration, ambient temperature parameters, and harmonic parameters in advance. During gas detection, the real-time gas concentration value can be quickly and accurately calculated using the relationship model based on the real-time ambient temperature parameters and real-time harmonic parameters. This invention does not require changing the position of the absorption pit by adjusting the laser operating temperature, nor does it require temperature compensation for the obtained real-time gas concentration value.

[0131] It should also be noted that the harmonic parameter V 2f / V 1f This refers to the ratio of the second harmonic amplitude to the first harmonic amplitude demodulated from the detector signal using a lock-in amplification algorithm in a TDLAS system. The specific calculation method is based on existing technology and will not be elaborated here.

[0132] Example 4

[0133] Based on the above embodiments, this embodiment provides a specific implementation of a computer device, which includes a processor, a communication interface, a memory, and a communication bus. The processor, the communication interface, and the memory communicate with each other through the communication bus. The memory is used to store computer programs. When the processor executes the program stored in the memory, it implements the laser gas detection method as in Embodiment 1, 2, or 3.

[0134] Based on the above embodiments, this embodiment also provides a readable storage medium, characterized in that: it stores instructions that, when executed by one or more processors, cause the processors to perform the laser gas detection method as described in Embodiment 1, 2, or 3.

[0135] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0136] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0137] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A laser gas detection method, characterized in that, include: A relationship model is pre-established among gas concentration, ambient temperature, and absorption pit area; wherein, the relationship model is expressed as: y = (a×x) 2 + b×x + c) ×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, and z represents the absorption pit area parameter obtained when there is gas; the absorption pit area parameter refers to the area of ​​the region enclosed by the light intensity waveform between the start and end points of the absorption pit and the baseline in the light intensity normalized waveform diagram, and the normalized value on the baseline is 1; a represents the first relationship coefficient, b represents the second relationship coefficient, and c represents the third relationship coefficient. Determine the real-time ambient temperature parameter and the real-time absorption pit area parameter; wherein, the real-time ambient temperature parameter refers to the AD value related to the real-time temperature around the laser; When determining the real-time absorption pit area parameters, execute: The collected detector signals are normalized to obtain the corresponding normalized light intensity waveform. Based on the normalized waveform of the light intensity, determine the starting point and the ending point of the absorption pit. First, the logarithm of the normalized value corresponding to the starting point of the absorption pit is calculated, then the logarithm of the normalized value corresponding to the ending point of the absorption pit is calculated, and finally the logarithm of each normalized value between the starting point and the ending point of the absorption pit is calculated. The logarithmic results are then accumulated and used as the real-time absorption pit area parameter. Wherein, the real-time absorption pit area parameter = ln(F i ) +…+ ln(F j ), F i F represents the normalized value corresponding to the starting point of the absorption pit. j This represents the normalized value corresponding to the endpoint of the absorption pit; The real-time gas concentration is calculated using the relationship model based on the real-time ambient temperature parameter and the real-time absorption pit area parameter.

2. A laser gas detection method, characterized in that, include: A relationship model is pre-established among gas concentration, ambient temperature, and absorption pit depth; wherein, the relationship model is expressed as: y = (a×x) 2 + b×x + c) ×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, and z represents the obtained absorption pit depth parameter when there is gas; the absorption pit depth parameter refers to the parameter corresponding to the difference between the normalized maximum value of light intensity and the reference value in the normalized light intensity waveform, and the normalized value corresponding to the reference value is 1; a represents the first relationship coefficient, b represents the second relationship coefficient, and c represents the third relationship coefficient. Determine the real-time ambient temperature parameter and the real-time absorption pit depth parameter; wherein, the real-time ambient temperature parameter refers to the AD value related to the real-time temperature around the laser; When determining the real-time absorption pit depth parameters, execute: The collected detector signals are normalized to obtain the corresponding normalized light intensity waveform. Based on the normalized light intensity waveform, the depth parameter A is determined; wherein, the depth parameter A refers to the maximum value of the normalized value between the start and end points of the absorption pit; Based on the depth parameter A, the real-time absorption pit depth parameter is calculated; wherein, the real-time absorption pit depth parameter = ln(A); The real-time gas concentration is calculated using the relationship model based on the real-time ambient temperature parameter and the real-time absorption pit depth parameter.

3. A laser gas detection method, characterized in that, include: A relationship model is pre-established among gas concentration, ambient temperature parameters, and harmonic parameters; wherein, the relationship model is expressed as: y = (a×x) 2 + b×x + c) ×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, z represents the obtained harmonic parameter when there is gas; a represents the first relation coefficient, b represents the second relation coefficient, and c represents the third relation coefficient; Determine the real-time ambient temperature parameter and the real-time harmonic parameter; wherein, the real-time ambient temperature parameter refers to the AD value related to the real-time temperature around the laser, and the harmonic parameter refers to the second harmonic amplitude V. 2f With the amplitude V of the first harmonic 1f The ratio; The real-time gas concentration is calculated using the relationship model based on the real-time ambient temperature parameters and the real-time harmonic parameters.

4. A laser gas detection system, characterized in that: It includes a relational model management module, a temperature parameter determination module, an area parameter determination module, and a gas concentration calculation module, among which, The relational model management module is used to pre-establish a relational model among gas concentration, ambient temperature parameters, and absorption pit area parameters; wherein, the relational model is expressed as: y = (a×x 2 + b×x + c) ×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, and z represents the absorption pit area parameter obtained when there is gas; the absorption pit area parameter refers to the area of ​​the region enclosed by the light intensity waveform between the start and end points of the absorption pit and the baseline in the light intensity normalized waveform diagram, and the normalized value on the baseline is 1; a represents the first relationship coefficient, b represents the second relationship coefficient, and c represents the third relationship coefficient. The temperature parameter determination module is used to determine the real-time ambient temperature parameter; wherein, the real-time ambient temperature parameter refers to the AD value related to the real-time temperature around the laser. The area parameter determination module is used to determine the real-time absorption pit area parameter; when determining the real-time absorption pit area parameter, the following is executed: The collected detector signals are normalized to obtain the corresponding normalized light intensity waveform. Based on the normalized waveform of the light intensity, determine the starting point and the ending point of the absorption pit. First, the logarithm of the normalized value corresponding to the starting point of the absorption pit is calculated, then the logarithm of the normalized value corresponding to the ending point of the absorption pit is calculated, and finally the logarithm of each normalized value between the starting point and the ending point of the absorption pit is calculated. The logarithmic results are then accumulated and used as the real-time absorption pit area parameter. Wherein, the real-time absorption pit area parameter = ln(F i ) +…+ ln(F j ), F i F represents the normalized value corresponding to the starting point of the absorption pit. j This represents the normalized value corresponding to the endpoint of the absorption pit; The gas concentration calculation module is used to calculate the real-time gas concentration based on the real-time ambient temperature parameter and the real-time absorption pit area parameter using the relationship model.

5. A laser gas detection system, characterized in that: It includes a relational model management module, a temperature parameter determination module, a depth parameter determination module, and a gas concentration calculation module. The relational model management module is used to pre-establish a relational model among gas concentration, ambient temperature parameters, and absorption pit depth parameters; wherein, the relational model is expressed as: y = (a×x 2 + b×x + c) ×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, z represents the obtained absorption pit depth parameter when there is gas; a represents the first relationship coefficient, b represents the second relationship coefficient, and c represents the third relationship coefficient; The temperature parameter determination module is used to determine the real-time ambient temperature parameter; wherein, the real-time ambient temperature parameter refers to the AD value related to the real-time temperature around the laser. The depth parameter determination module is used to determine the real-time absorption pit depth parameter; when determining the real-time absorption pit depth parameter, the following is executed: The collected detector signals are normalized to obtain the corresponding normalized light intensity waveform. Based on the normalized light intensity waveform, the depth parameter A is determined; wherein, the depth parameter A refers to the maximum value of the normalized value between the start and end points of the absorption pit; Based on the depth parameter A, the real-time absorption pit depth parameter is calculated; wherein, the real-time absorption pit depth parameter = ln(A); The gas concentration calculation module is used to calculate the real-time gas concentration based on the real-time ambient temperature parameter and the real-time absorption pit depth parameter using the relationship model.

6. A laser gas detection system, characterized in that: It includes a relational model management module, a temperature parameter determination module, a harmonic parameter determination module, and a gas concentration calculation module. The relational model management module is used to pre-establish a relational model among gas concentration, ambient temperature parameters, and harmonic parameters; wherein, the relational model is expressed as: y = (a×x 2 + b×x + c) ×z, where y represents the gas concentration, x represents the obtained ambient temperature parameter, z represents the obtained harmonic parameter when there is gas; a represents the first relation coefficient, b represents the second relation coefficient, and c represents the third relation coefficient; The temperature parameter determination module is used to determine the real-time ambient temperature parameter; wherein, the real-time ambient temperature parameter refers to the AD value related to the real-time temperature around the laser. The harmonic parameter determination module is used to determine real-time harmonic parameters; wherein, the harmonic parameter refers to the second harmonic amplitude V. 2f With the amplitude V of the first harmonic 1f The ratio; The gas concentration calculation module is used to calculate the real-time gas concentration based on the real-time ambient temperature parameter and the real-time harmonic parameter using the relationship model.

7. A computer device, characterized in that: It includes a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; Memory, used to store computer programs; The processor, when executing a program stored in memory, implements the laser gas detection method as described in any one of claims 1 to 3.

8. A readable storage medium, characterized in that: It stores instructions that, when executed by one or more processors, cause the processors to perform the laser gas detection method as described in any one of claims 1 to 3.

Images