Gas detection method and device, electronic equipment and computer readable storage medium

Abstract

The invention provides a gas detection method and device, electronic equipment and a computer readable storage medium, and the method comprises the following steps: respectively processing a first background light intensity signal and a second background light intensity signal obtained by a test light beam through reference gas, controlling the test light beam to pass through to-be-detected gas to obtain an absorption light intensity signal; obtaining a first target array to a sixth target array; dividing the fourth target array by the first target array to obtain a first polynomial quotient; dividing the second target array by the fifth target array to obtain a second polynomial quotient; dividing the third target array by the sixth target array to obtain a third polynomial quotient; calculating a target difference value according to a plurality of difference values among the first polynomial quotient, the second polynomial quotient and the third polynomial quotient; determining to-be-detected parameters of the to-be-detected gas based on the target difference value and a set relation; the target difference value is determined according to the polynomial quotient, the method can be suitable for gas detection under various interference fringes, and interference compatibility and sensitivity are better.

Description

Technical Field

[0001] The present application relates to the field of gas detection, and in particular, to a gas detection method, device, electronic device and computer-readable storage medium. Background Art

[0002] The commonly used algorithm model involved in TDLAS technology is: a current-driven laser with a low-frequency sawtooth signal superimposed on a high-frequency sinusoidal signal. After the modulated light beam passes through the gas to be measured, the light signal is received by the photodetector and transmitted to the phase-locked amplifier to extract the second harmonic signal. Generally, the central peak height of the second harmonic signal is corresponding to the concentration of the standard gas, so as to measure the gas concentration. However, when the interference fringes of the test beam change, the gas concentration detected by this method is quite different, and this method is not suitable for situations where the interference fringes change. Summary of the invention

[0003] In view of this, an object of the embodiments of the present application is to provide a gas detection method, device, electronic device and computer-readable storage medium with better interference compatibility.

[0004] In a first aspect, an embodiment of the present application provides a gas detection method, comprising: controlling a test light beam to pass through a reference gas to obtain a first background light intensity signal and a second background light intensity signal, and controlling the test light beam to pass through a gas to be tested to obtain an absorption light intensity signal; wherein the first background light intensity signal and the second background light intensity signal are adjacent light intensity signals; using Fourier transform to process the first background light intensity signal, the second background light intensity signal and the absorption light intensity signal respectively to obtain a first frequency domain array, a second frequency domain array and a third frequency domain array; obtaining a first preset number of complex numbers around a modulation frequency in the first frequency domain array to obtain a first target array; obtaining a first preset number of complex numbers around a modulation frequency in the second frequency domain array to obtain a second target array; and obtaining a first preset number of complex numbers around a modulation frequency in the third frequency domain array to obtain a third target array; obtaining a second preset number of complex numbers in the first frequency domain array in a forward-to-backward order, Obtain a fourth target array; obtain a second preset number of complex numbers in the second frequency domain array in order from front to back to obtain a fifth target array; and obtain a second preset number of complex numbers in the third frequency domain array in order from front to back to obtain a sixth target array; obtain the first polynomial quotient by dividing the first target array by the fourth target array; obtain the second polynomial quotient by dividing the second target array by the fifth target array; and obtain the third polynomial quotient by dividing the third target array by the sixth target array; calculate a target difference according to multiple differences between the first polynomial quotient, the second polynomial quotient and the third polynomial quotient; wherein the first polynomial quotient, the second polynomial quotient and the third polynomial quotient are all arrays; determine the measured parameter of the gas to be measured based on the target difference and a set relationship; wherein the set relationship is used to characterize the relationship between the target difference and the measured parameter of the gas to be measured.

[0005] In the above implementation process, the first background light intensity signal and the second background light intensity signal obtained by the test light beam passing through the reference gas are Fourier transformed to obtain the corresponding first frequency domain array, second frequency domain array and third frequency domain array, and then the first polynomial quotient, the second polynomial quotient and the third polynomial quotient are determined according to the first frequency domain array, the second frequency domain array and the third frequency domain array, and the target difference is determined according to the difference between the first polynomial quotient, the second polynomial quotient and the third polynomial quotient. This method can be adapted to the detection of gases under a variety of interference fringes, has better interference compatibility and sensitivity, and increases the application scenarios of the gas detection method while improving the accuracy of gas detection.

[0006] In one embodiment, the first preset number is determined by the expression 2(m*n)+1; wherein m and n are both positive integers; and the second preset number is m.

[0007] In the above implementation process, by setting the first preset number and the second preset number, the calculation of the polynomial division of the first preset number and the second preset number can be realized, and then the target difference is calculated, and finally the detection of gas under different interference fringes is realized, which can make the gas detection method of the present application have better interference compatibility and detection sensitivity.

[0008] In one embodiment, the target difference is calculated based on multiple differences between the first polynomial quotient, the second polynomial quotient and the third polynomial quotient, including: subtracting the third polynomial quotient from the first polynomial quotient to obtain a first intermediate array; taking the absolute value of each element in the first intermediate array, and then summing up the absolute values ​​to obtain a first numerical value; subtracting the first polynomial quotient from the second polynomial quotient to obtain a second intermediate array; taking the absolute value of each element in the second intermediate array, and then summing up the absolute values ​​to obtain a second numerical value; subtracting the first numerical value from the second numerical value to obtain the target difference.

[0009] In the above implementation process, the first value and the second value are obtained by taking the absolute value of each element in the first intermediate array and the second intermediate array and then summing them. Then, by calculating the difference between the first value and the second value, the target difference when the light beam passes through the reference gas can be returned to zero, which is beneficial for the marking line to cross the zero point and reduce the calibration workload.

[0010] In one embodiment, before controlling the test beam to obtain the first background light intensity signal and the second background light intensity signal through the reference gas, and controlling the test beam to obtain the absorption light intensity signal through the gas to be tested, the method also includes: modulating the test beam; the modulated test beam passes through a set environment to generate corresponding interference fringes; controlling the test beam to obtain the first background light intensity signal and the second background light intensity signal through the reference gas, and controlling the test beam to obtain the absorption light intensity signal through the gas to be tested, including: controlling the test beam that generates interference fringes to obtain the first background light intensity signal and the second background light intensity signal through the reference gas, and controlling the test beam that generates interference fringes to obtain the absorption light intensity signal through the gas to be tested.

[0011] In the above implementation process, by first modulating the test beam, the interference of noise can be suppressed, thereby improving the accuracy of the final test result. In addition, after the test beam passes through the set environment to generate interference fringes, by obtaining the first background light intensity signal, the second background light intensity signal and the absorption light intensity signal under the corresponding interference fringes, the gas under different interference fringes can be detected, which has better interference compatibility and sensitivity.

[0012] In one embodiment, the reference gas is nitrogen, and the gas to be tested is ammonia.

[0013] In the above implementation process, the embodiment of the present application determines the target difference based on the first background light intensity signal, the second background light intensity signal obtained by the test light beam through the reference gas, and the first polynomial quotient, the second polynomial quotient and the third polynomial quotient after processing the absorption light intensity signal obtained by the test light beam through the gas to be tested, and then determines the corresponding test parameters of the gas to be tested based on the target difference. It can be adapted to the detection of gases under a variety of interference fringes, has better interference compatibility and sensitivity, and increases the scenario applicability of the gas detection method while improving the accuracy of gas detection.

[0014] In one embodiment, the determination of the measured parameter of the measured gas based on the target difference and the set relationship is achieved through the following relationship: Y=kx+b; wherein Y is the target difference, x is the measured parameter, k is a coefficient, and b is a constant.

[0015] In a second aspect, an embodiment of the present application further provides a TDLAS system, comprising: a laser driver, a laser, a gas chamber, a photodetector, a modulation acquisition module and an electronic device; the input end of the laser driver is connected to the modulation acquisition module, and the output end of the laser driver is connected to the input end of the laser; the laser driver is configured to drive the laser; the laser is configured to generate a test beam, and the gas chamber is configured to accommodate a reference gas or a gas to be tested; the output end of the photodetector is connected to the input end of the modulation acquisition module; wherein the light beam emitted by the laser passes through the gas chamber and is received by the photodetector; the electronic device is connected to one or more of the laser driver, the laser, the gas chamber, the photodetector and the modulation acquisition module; wherein the electronic device is configured to perform the steps of the above-mentioned first aspect, or any possible implementation method of the first aspect.

[0016] In a third aspect, an embodiment of the present application further provides a gas detection device, comprising: a control module, controlling a test light beam to obtain a first background light intensity signal and a second background light intensity signal through a reference gas, and controlling the test light beam to obtain an absorption light intensity signal through a gas to be tested; wherein the first background light intensity signal and the second background light intensity signal are adjacent light intensity signals; a calculation module, for using Fourier transform to process the first background light intensity signal, the second background light intensity signal and the absorption light intensity signal respectively, to obtain a first frequency domain array, a second frequency domain array and a third frequency domain array; the calculation module is also used to obtain a first preset number of complex numbers around the modulation frequency in the first frequency domain array to obtain a first target array; obtain a first preset number of complex numbers around the modulation frequency in the second frequency domain array to obtain a second target array; and obtain a first preset number of complex numbers around the modulation frequency in the third frequency domain array to obtain a third target array; obtain a second preset number of complex numbers in the first frequency domain array in order from front to back to obtain a fourth Target array; obtaining a second preset number of complex numbers in the second frequency domain array in order from front to back to obtain a fifth target array; and obtaining a second preset number of complex numbers in the third frequency domain array in order from front to back to obtain a sixth target array; obtaining the first polynomial quotient by dividing the first target array by the fourth target array; obtaining the second polynomial quotient by dividing the second target array by the fifth target array; and obtaining the third polynomial quotient by dividing the third target array by the sixth target array; first array second array third array; the calculation module is also used to calculate a target difference based on multiple differences between the first polynomial quotient, the second polynomial quotient and the third polynomial quotient; wherein the first polynomial quotient, the second polynomial quotient and the third polynomial quotient are all arrays; a determination module is used to determine the measured parameter of the gas to be measured based on the target difference and a set relationship; wherein the set relationship is used to characterize the relationship between the target difference and the measured parameter of the gas to be measured.

[0017] In a fourth aspect, an embodiment of the present application further provides an electronic device, comprising: a processor and a memory, wherein the memory stores machine-readable instructions executable by the processor, and when the electronic device is running, the machine-readable instructions are executed by the processor to perform the steps of the above-mentioned first aspect, or any possible implementation method of the first aspect.

[0018] In a fifth aspect, an embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the gas detection method in the above-mentioned first aspect, or any possible implementation of the first aspect are executed.

[0019] In order to make the above-mentioned objects, features and advantages of the present application more obvious and understandable, embodiments are given below and described in detail with reference to the attached drawings.

[0020] In order to make the above-mentioned objects, features and advantages of the present application more obvious and understandable, embodiments are given below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 A schematic diagram of a TDLAS system provided in an embodiment of the present application;

[0023] Figure 2 Light intensity signals under different interference states provided by the embodiments of the present application;

[0024] Figure 3 A schematic block diagram of an electronic device provided in an embodiment of the present application;

[0025] Figure 4 A flow chart of a gas detection method provided in an embodiment of the present application;

[0026] Figure 5 A detailed process flow chart of the gas detection method provided in the embodiment of the present application;

[0027] Figure 6 The second harmonic signals of the reference gas and the gas to be measured under different interference states of the second harmonic method provided in the embodiment of the present application;

[0028] Figure 7 Fourier change spectra of the reference gas and the gas to be measured in interference state 1 and interference state 2 provided in the embodiment of the present application;

[0029] Figure 8 The detection results of the second harmonic signals of the reference gas and the gas to be tested under different states of the second harmonic method in the prior art;

[0030] Fig. 9 It is a schematic diagram of gas concentration detection results of the existing optical interference effect of the second harmonic method in the prior art;

[0031] Fig.10 A schematic diagram of gas concentration detection results in the gas detection method of the present application provided in an embodiment of the present application;

[0032] Fig.11 A schematic diagram of the functional modules of the gas detection device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings in the embodiments of the present application.

[0034] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0035] TDLAS (Tunable Diod Laser Absorption Spectroscopy), tunable semiconductor absorption spectroscopy technology. For most gas analysis instruments, such as ammonia analyzers based on TDLAS technology, due to the existence of the gas chamber and window in the system, and due to the "FP" effect (Fabry Perot effect) on both surfaces of the window, irregular "wave" interference fringes will be introduced into the optical signal driven by the rising edge of the sawtooth wave.

[0036] The relationship between the window thickness and the half wavelength (λ / 2) determines the strength and position of the interference effect. The wavelength of the laser used in TDLAS technology is fixed. When the temperature of the air chamber or window changes, the thickness of the window will change slightly due to thermal expansion and contraction, which will cause the position of the interference fringes to change. Or, when the optical window moves relative to the optical path system, the change in the incident angle will also cause the interference fringes to change.

[0037] The inventor of the present application has found through long-term research that when the interference fringes change, if the classical second harmonic method is still used to demodulate the absorption signals before and after the interference fringes change, the amplitude changes greatly, and even the second harmonic signal before and after the interference fringes change is in the opposite direction to the change trend of the measured gas concentration. In other words, when the interference state 2 is measured using the marking line made by the interference state 1, when the same concentration of NH3 standard gas is filled, the concentration value obtained is close to zero or negative. This makes the second harmonic method unable to be used for gas detection under different interference states.

[0038] In view of this, the present application proposes a gas detection method, which performs Fourier transform on the first background light intensity signal and the second background light intensity signal obtained by the test light beam passing through the reference gas to obtain the corresponding first frequency domain array, second frequency domain array and third frequency domain array, and then determines the first polynomial quotient, the second polynomial quotient and the third polynomial quotient according to the first frequency domain array, the second frequency domain array and the third frequency domain array, and determines the target difference according to the difference between the first polynomial quotient, the second polynomial quotient and the third polynomial quotient. This method can be adapted to the detection of gases under a variety of interference fringes, has better interference compatibility and sensitivity, and increases the application scenarios of the gas detection method while improving the accuracy of gas detection.

[0039] To facilitate understanding of this embodiment, a TDLAS system for executing a gas detection method disclosed in an embodiment of the present application is first introduced in detail.

[0040] like Figure 1 , which is a schematic diagram of a TDLAS system provided in an embodiment of the present application, including: a laser driver 200, a laser 300, a gas chamber 400, a photodetector 500 and a modulation acquisition module 600 (ie, MCU).

[0041] Among them, the input end of the laser driver 200 is connected to the modulation acquisition module 600, and the output end of the laser driver 200 is connected to the input end of the laser 300; after the light beam generated by the laser passes through the gas chamber 400, it is received by the photodetector 500, and the output end of the photodetector 500 is connected to the input end of the modulation acquisition module 600.

[0042] The laser driver 200 is configured to drive the laser 300. The laser driver 200 provides current driving and temperature control driving to the laser 300. The laser driver 200 can adjust the laser 300 in a manner selected according to actual conditions.

[0043] The laser 300 is configured to generate laser light for providing a light beam.

[0044] In one embodiment, the driving signal of the laser 300 current includes a low-frequency sawtooth wave superimposed on a high-frequency sine wave, wherein the modulation frequency of the sine wave is f.

[0045] After the light beam generated by the laser 300 passes through the gas chamber 400, part of the light intensity is absorbed by the gas in the gas chamber 400, and the remaining light intensity is received by the photodetector 500. The photodetector 500 converts the received light signal into an electrical signal, which is then collected by the drive collection module after amplification and filtering, and transmitted to the central processor.

[0046] In one embodiment, the photodetector 500 is configured to convert an optical signal into an electrical signal, and to amplify the signal.

[0047] Understandably, if Figure 1 As shown, optical windows 410 are provided at both ends of the gas chamber 400. If the temperature of the TDLAS system changes, or components such as the optical window 410 move relative to the optical path, the interference fringes of the optical signal received by the photodetector 500 may change. Figure 2 As shown by the black lines in ① and ③, the fluctuation trends before and after the change are different.

[0048] The gas chamber 400 is configured to contain a reference gas or a gas to be tested.

[0049] In one embodiment, the TDLAS system further includes an electronic device 100, which is connected to one or more of the laser driver 200, the laser 300, the gas chamber 400, the photodetector 500, and the modulation acquisition module 600. The electronic device 100 is configured to execute the gas detection method in the embodiment of the present application.

[0050] To facilitate understanding of this embodiment, the electronic device that executes the gas detection method disclosed in the embodiment of the present application is introduced in detail below.

[0051] like Figure 3 , which is a block diagram of an electronic device. The electronic device 100 may include a memory 111 and a processor 113. A person skilled in the art may understand that Figure 3 The structure shown is only for illustration and does not limit the structure of the electronic device 100. For example, the electronic device 100 may further include Figure 3 More or fewer components as shown, or with Figure 3 Different configurations are shown.

[0052] The memory 111 and the processor 113 are directly or indirectly electrically connected to each other to achieve data transmission or interaction. For example, these elements can be electrically connected to each other via one or more communication buses or signal lines. The processor 113 is used to execute the executable module stored in the memory.

[0053] The memory 111 may be, but is not limited to, a random access memory (RAM), a read only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable read-only memory (EEPROM), etc. The memory 111 is used to store programs, and the processor 113 executes the program after receiving the execution instruction. The method executed by the electronic device 100 defined by the process disclosed in any embodiment of the present application can be applied to the processor 113, or implemented by the processor 113.

[0054] The processor 113 may be an integrated circuit chip with signal processing capability. The processor 113 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present application may be implemented or executed. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0055] The electronic device 100 in this embodiment can be used to execute each step in each method provided in the embodiments of the present application. The implementation process of the gas detection method is described in detail below through several embodiments.

[0056] See also Figure 4 , Figure 5 , is a flow chart of the gas detection method provided in the embodiment of the present application. Figure 4 The specific process shown is described in detail.

[0057] Step S201, controlling the test light beam to pass through the reference gas to obtain a first background light intensity signal and a second background light intensity signal, and controlling the test light beam to pass through the gas to be tested to obtain an absorption light intensity signal.

[0058] The test beam here is a beam emitted by a laser, for example, an infrared beam, a visible beam, an ultraviolet beam, etc. The type of the test beam can be selected according to actual conditions.

[0059] The reference gas has stable chemical and physical properties under specific conditions. The reference gas can be an inert gas with known chemical composition and physical properties, such as nitrogen. The reference gas can be adjusted according to the gas to be measured.

[0060] The first background light intensity signal and the second background light intensity signal may be adjacent light intensity signals.

[0061] In one embodiment, the first background light intensity signal and the second background light intensity signal can be obtained by continuously acquiring light intensity signals after the test light beam passes through the reference gas twice.

[0062] The above-mentioned gas to be measured is a gas whose parameters need to be measured, for example, ammonia, oxygen, carbon monoxide, carbon dioxide, nitric oxide, methane, propane, etc. The gas to be measured can be selected according to actual conditions.

[0063] Step S202, using Fourier transform to process the first background light intensity signal, the second background light intensity signal and the absorption light intensity signal respectively to obtain a first frequency domain array, a second frequency domain array and a third frequency domain array.

[0064] Step S203, obtain a first preset number of complex numbers around the modulation frequency in the first frequency domain array to obtain a first target array; obtain a first preset number of complex numbers around the modulation frequency in the second frequency domain array to obtain a second target array; and obtain a first preset number of complex numbers around the modulation frequency in the third frequency domain array to obtain a third target array.

[0065] Step S204, obtaining the second preset number of complex numbers in the first frequency domain array in order from front to back, to obtain a fourth target array; obtaining the second preset number of complex numbers in the second frequency domain array in order from front to back, to obtain a fifth target array; and obtaining the second preset number of complex numbers in the third frequency domain array in order from front to back, to obtain a sixth target array.

[0066] Step S205, obtaining a first polynomial quotient by dividing the first target array by the fourth target array; obtaining a second polynomial quotient by dividing the second target array by the fifth target array; and obtaining a third polynomial quotient by dividing the third target array by the sixth target array.

[0067] The modulation frequency here is determined according to the driving signal of the laser. The complex numbers in the first target array are the complex numbers distributed around the modulation frequency in the first frequency domain array. The complex numbers in the second target array are the complex numbers distributed around the modulation frequency in the second frequency domain array. For example, if the first preset number is 5, the complex numbers in the first target array are the 2 complex numbers distributed in front of the modulation frequency in the first frequency domain array, the value corresponding to the modulation frequency, and the 2 complex numbers distributed behind the modulation frequency. The complex numbers in the second target array are the 2 complex numbers distributed in front of the modulation frequency, the value corresponding to the modulation frequency, and the 2 complex numbers distributed behind the modulation frequency in the second frequency domain array. The complex numbers in the third target array are the 2 complex numbers distributed in front of the modulation frequency, the value corresponding to the modulation frequency, and the 2 complex numbers distributed behind the modulation frequency in the third frequency domain array.

[0068] For another example, if the first preset number is 7, the complex numbers in the first target array are the 4 complex numbers distributed before the modulation frequency, the value corresponding to the modulation frequency, and the 3 complex numbers distributed after the modulation frequency in the first frequency domain array. The complex numbers in the second target array are the 4 complex numbers distributed before the modulation frequency, the value corresponding to the modulation frequency, and the 3 complex numbers distributed after the modulation frequency in the second frequency domain array. The complex numbers in the third target array are the 4 complex numbers distributed before the modulation frequency, the value corresponding to the modulation frequency, and the 3 complex numbers distributed after the modulation frequency in the third frequency domain array.

[0069] The fourth target array is the first second preset number of complex numbers in the first frequency domain array from front to back. The fifth target array is the first second preset number of complex numbers in the second frequency domain array. The sixth target array is the first second preset number of complex numbers in the third frequency domain array. For example, if the second preset number is 4, the fourth target array is the first 4 complex numbers in the first frequency domain array, the fifth target array is the first 4 complex numbers in the second frequency domain array, and the sixth target array is the first 4 complex numbers in the third frequency domain array.

[0070] For another example, the second preset number is 5, the fourth target array is the first 5 complex numbers in the first frequency domain array, the fifth target array is the first 5 complex numbers in the second frequency domain array, and the sixth target array is the first 5 complex numbers in the third frequency domain array.

[0071] The value taking method of the above-mentioned first target array, second target array, third target array, fourth target array, fifth target array and sixth target array can be a value taking method that includes an intermediate modulation frequency and a symmetrical value taking method on its left and right sides.

[0072] It should be understood that when calculating the first target array divided by the fourth target array, the lengths of the first target array and the fourth target array may be different, and the two use polynomial division to obtain a first polynomial quotient. When calculating the second target array divided by the fifth target array, the lengths of the second target array and the fifth target array may be different, and the two use polynomial division to obtain a second polynomial quotient. When calculating the third target array divided by the sixth target array, the lengths of the third target array and the sixth target array may be different, and the two use polynomial division to obtain a third polynomial quotient.

[0073] The first polynomial quotient, the second polynomial quotient and the third polynomial quotient are all arrays.

[0074] Step S206, calculating a target difference value according to a plurality of differences between the first polynomial quotient, the second polynomial quotient and the third polynomial quotient.

[0075] It should be understood that when any two of the first polynomial quotient, the second polynomial quotient, and the third polynomial quotient are subtracted from each other, each element in the array is subtracted from each other.

[0076] The multiple difference values ​​here may include: a difference value obtained by subtracting a value at a corresponding position of the third polynomial quotient from a value at a corresponding position of the first polynomial quotient, a difference value obtained by subtracting a value at a corresponding position of the first polynomial quotient from a value at a corresponding position of the second polynomial quotient, and the like.

[0077] Step S207, determining the measured parameter of the measured gas based on the target difference and the set relationship.

[0078] The set relationship is used to characterize the relationship between the target difference and the measured parameter of the measured gas.

[0079] The target difference here can be used to characterize the interference state of the light beam signal and the parameter information to be measured.

[0080] Optionally, a setting relationship between the target difference and the parameter to be measured can be set in advance and stored. After the target difference is calculated, the parameter to be measured can be directly inverted according to the target difference.

[0081] In one embodiment, the inversion of the corresponding measured parameter according to the target difference can be achieved through the following first-order linear relationship:

[0082] Y = kx + b;

[0083] Wherein, Y is the target difference, x is the parameter to be measured, k is a coefficient, and b is a constant. It is also possible to calculate the corresponding parameter to be measured based on the target difference and the first set calculation formula of the parameter to be measured. After the target difference is calculated, the corresponding parameter to be measured can be calculated based on the target difference and the first set calculation formula.

[0084] The above-mentioned method for determining the parameters to be measured is only exemplary, and the method for determining the parameters to be measured can be selected according to actual conditions.

[0085] The parameters to be measured here may be concentration, humidity and other parameters, and the parameters to be measured may be selected according to actual conditions.

[0086] In the above implementation process, the first background light intensity signal and the second background light intensity signal obtained by the test light beam passing through the reference gas are Fourier transformed to obtain the corresponding first frequency domain array, second frequency domain array and third frequency domain array, and then the first polynomial quotient, the second polynomial quotient and the third polynomial quotient are determined according to the first frequency domain array, the second frequency domain array and the third frequency domain array, and the target difference is determined according to the difference between the first polynomial quotient, the second polynomial quotient and the third polynomial quotient. This method can be adapted to the detection of gases under a variety of interference fringes, has better interference compatibility and sensitivity, and increases the application scenarios of the gas detection method while improving the accuracy of gas detection.

[0087] In a possible implementation, the first preset number is determined by the expression 2(m*n)+1; and the second preset number is m.

[0088] Wherein, m and n are both positive integers.

[0089] In the above implementation process, by setting the first preset number and the second preset number, the calculation of the polynomial division of the first preset number and the second preset number can be realized, and then the target difference is calculated, and finally the detection of gas under different interference fringes is realized, which can make the gas detection method of the present application have better interference compatibility and detection sensitivity.

[0090] In one possible implementation, Figure 5 As shown, step S206 includes: subtracting the third polynomial quotient from the first polynomial quotient to obtain a first intermediate array; taking the absolute value of each element in the first intermediate array, and then summing up the absolute values ​​to obtain a first value; subtracting the first polynomial quotient from the second polynomial quotient to obtain a second intermediate array; taking the absolute value of each element in the second intermediate array, and then summing up the absolute values ​​to obtain a second value; subtracting the first value from the second value to obtain a target difference.

[0091] Compared with the existing classical second harmonic method, the gas detection method in the embodiment of the present application is more suitable for gas detection under the change of interference conditions. The following is a specific experimental result of gas detection using different methods under two interference conditions to further illustrate the effect of the embodiment of the present application:

[0092] like Figure 2 As shown, Figure 2As shown in the figure, the reference gas is passed through the gas chamber, and the corresponding background light intensity signal is as follows Figure 2 The gas to be measured is passed through the gas chamber, and the corresponding absorption light intensity signal is shown as Figure 2 As shown in curves ② and ④ in .

[0093] Respectively Figure 2 The four light intensity signals in the Figure 6 The results shown in the figure show that there is an obvious positive difference between the absorption light intensity signal ② and the background light intensity signal ① in interference state 1; while the peak values ​​of the background light intensity signal ③ and the absorption light intensity signal ④ in interference state 2 are almost the same, and ④ is even slightly smaller than ③. It can be seen that the second harmonic method has poor compatibility with different interference states.

[0094] Continue with Figure 2 As shown in the figure, ① red is the modulated light intensity signal, and black is the filtered light signal. The fluctuation of the black line is caused by the interference effect.

[0095] Figure 2 Curves ① and ② in the figure are the background light intensity signal and the absorption light intensity signal collected in interference state 1, and curves ③ and ④ are the background light intensity signal and the absorption light intensity signal collected in interference state 2. After data processing according to the above gas detection method, the following is obtained: Figure 7 The Fourier transform spectrum of the modulation frequency is shown in the figure on the left. The spectrum on the right is near the modulation frequency.

[0096] After polynomial division of the reference gas and the measured gas absorption spectra in interference state 2, we can obtain Fig.10 The amplitude results ③ and ④ are shown in the figure. That is, in the two interference states, when the reference gas is introduced into the air chamber respectively, the amplitude is equivalent, and when the same concentration of the test gas is introduced into the air chamber, the amplitude is very close, and the concentration value obtained is also similar. That is, the gas detection method in the embodiment of the present application is more compatible with different interference fringes.

[0097] In the above implementation process, the first value and the second value are obtained by taking the absolute value of each element in the first intermediate array and the second intermediate array and then summing them. Then, by calculating the difference between the first value and the second value, the target difference when the light beam passes through the reference gas can be returned to zero, which is beneficial for the marking line to cross the zero point and reduces the difficulty of calibration.

[0098] In a possible implementation, before step S201, the method further includes: modulating the test light beam; and the modulated test light beam passes through a set environment to generate corresponding interference fringes.

[0099] In one embodiment, step S201 includes: controlling the test light beam that generates interference fringes to pass through a reference gas to obtain a first background light intensity signal and a second background light intensity signal, and controlling the test light beam that generates interference fringes to pass through a gas to be tested to obtain an absorption light intensity signal.

[0100] The setting environment here refers to the environment where the gas chamber is located. The setting environment may include optical windows, various types of optical components, etc. Among them, parameters such as the thickness of the optical window and the temperature of the optical component may affect the interference fringes generated after the test beam passes through.

[0101] Optionally, the test light beam may be subjected to a variety of modulation modes such as intensity modulation and frequency modulation, and the modulation method of the test light beam may be selected according to actual conditions.

[0102] In the above implementation process, by first modulating the test beam, the interference of noise can be suppressed, thereby improving the accuracy of the final test result. In addition, after the test beam passes through the set environment to generate interference fringes, by obtaining the first background light intensity signal, the second background light intensity signal and the absorption light intensity signal under the corresponding interference fringes, the gas under different interference fringes can be detected, which has better interference compatibility and sensitivity.

[0103] In a possible implementation, the reference gas is nitrogen and the gas to be measured is ammonia.

[0104] Compared with the existing optical interference effect gas concentration detection method (hereinafter referred to as method 1), the gas detection method in the embodiment of the present application (hereinafter referred to as method 2) can be compatible with gas detection under more interference conditions when performing gas detection. The following is a specific experimental result of using different methods to perform gas detection under two interference states to further illustrate the effect of the embodiment of the present application:

[0105] Continue to use Figure 2 The background light intensity signal and the absorption light intensity signal under the two interference states are obtained by using the existing gas concentration detection method of optical interference effect. Fig. 9 The results obtained by using the gas detection method in the embodiment of the present application are as follows Fig.10 shown.

[0106] In addition, the two methods are compared to calculate Figure 2 The average values ​​of the results obtained from the four light intensity signals can be found in Table 1:

[0107] Table 1:

[0108]

[0109] As can be seen from Table 1, the results of the calculation of the four light intensity signals under the two methods. In actual calculation, the amplitude of the absorption of the gas to be measured (i.e., ammonia) under the same interference state is deducted from the amplitude of the absorption of the reference gas (i.e., nitrogen) to obtain the amplitude corresponding to the gas to be measured under the interference state. The amplitudes of the gas to be measured under the two interference states calculated by the two methods are referred to Table 2.

[0110] Table 2:

[0111] Different interference states Method 1 Amplitude Method 2 Amplitude Interference state 1 0.119984 0.302403 Interference state 2 0.089493 0.265879 Deviation of two interference amplitudes / % -25.41 -12.08

[0112] As shown in Table 2, Method 1 and Method 2 calculate Figure 6 The relative deviations of the amplitudes in the two interference states are -25.41% and -12.08% respectively. The calculation formula of the relative deviation is: (amplitude of interference state 2 - amplitude of interference state 1) / interference state 1*100.

[0113] At the same time, it can be seen from Table 2 that the amplitude of the gas to be tested obtained by the method provided by the present invention is significantly higher than the amplitude of the gas to be tested obtained by Method 1. It can be seen that the sensitivity of the method provided in the embodiment of the present application (sensitivity is the difference in amplitude change corresponding to a change in concentration of the standard gas by one unit) is better than Method 1.

[0114] It can be seen that the method 2 provided by the present invention has better interference compatibility than the method 1. That is to say, under different interference states, when the same concentration of the gas to be tested is filled in the gas chamber, the amplitude results obtained by using the method provided by the embodiment of the present application are closer, and after establishing the calibration relationship between the amplitude and the concentration, a closer concentration value can be obtained.

[0115] In the above implementation process, the embodiment of the present application determines the target difference based on the first background light intensity signal, the second background light intensity signal obtained by the test light beam through the reference gas, and the first polynomial quotient, the second polynomial quotient and the third polynomial quotient after processing the absorption light intensity signal obtained by the test light beam through the gas to be tested, and then determines the corresponding test parameters of the gas to be tested based on the target difference. It can be adapted to the detection of gases under a variety of interference fringes, has better interference compatibility and sensitivity, and increases the application scenarios of the gas detection method while improving the accuracy of gas detection.

[0116] Based on the same application concept, a gas detection device corresponding to the gas detection method is also provided in the embodiment of the present application. Since the principle of solving the problem by the device in the embodiment of the present application is similar to that of the aforementioned gas detection method embodiment, the implementation of the device in this embodiment can refer to the description in the embodiment of the above method, and the repeated parts will not be repeated.

[0117] See also Fig.10, is a functional module diagram of a gas detection device provided in an embodiment of the present application. Each module in the gas detection device in this embodiment is used to execute each step in the above method embodiment. The gas detection device includes a control module 901, a calculation module 902, and a determination module 903;

[0118] Among them, the control module 901 is used to control the test light beam to obtain a first background light intensity signal and a second background light intensity signal through the reference gas, and to control the test light beam to obtain an absorption light intensity signal through the gas to be tested; wherein the first background light intensity signal and the second background light intensity signal are adjacent light intensity signals.

[0119] The calculation module 902 is used to process the first background light intensity signal, the second background light intensity signal and the absorption light intensity signal respectively by Fourier transform to obtain a first frequency domain array, a second frequency domain array and a third frequency domain array.

[0120] The calculation module 902 is also used to obtain a first preset number of complex numbers around the modulation frequency in the first frequency domain array to obtain a first target array; obtain a first preset number of complex numbers around the modulation frequency in the second frequency domain array to obtain a second target array; and obtain a first preset number of complex numbers around the modulation frequency in the third frequency domain array to obtain a third target array; obtain a second preset number of complex numbers in the first frequency domain array in order from front to back to obtain a fourth target array; obtain a second preset number of complex numbers in the second frequency domain array in order from front to back to obtain a fifth target array; and obtain a second preset number of complex numbers in the third frequency domain array in order from front to back to obtain a sixth target array; divide the first target array by the fourth target array to obtain the first polynomial quotient; divide the second target array by the fifth target array to obtain the second polynomial quotient; and divide the third target array by the sixth target array to obtain the third polynomial quotient.

[0121] The calculation module 902 is further used to calculate a target difference value according to a plurality of differences between the first polynomial quotient, the second polynomial quotient and the third polynomial quotient; wherein the first polynomial quotient, the second polynomial quotient and the third polynomial quotient are all arrays.

[0122] The determination module 903 is used to determine the parameter to be measured of the gas to be measured based on the target difference and the set relationship; wherein the set relationship is used to characterize the relationship between the target difference and the parameter to be measured of the gas to be measured.

[0123] In a possible implementation, the calculation module 902 is further specifically used to: subtract the third polynomial quotient from the first polynomial quotient to obtain a first intermediate array; take the absolute value of each element in the first intermediate array, and then sum the absolute values ​​to obtain a first value; subtract the first polynomial quotient from the second polynomial quotient to obtain a second intermediate array; take the absolute value of each element in the second intermediate array, and then sum the absolute values ​​to obtain a second value; subtract the first value from the second value to obtain the target difference.

[0124] In a possible implementation manner, the gas detection device further includes a modulation module, which is used to modulate the test light beam; the modulated test light beam passes through a set environment to generate corresponding interference fringes.

[0125] In a possible implementation, the control module 901 is specifically used to: control the test light beam that generates interference fringes to obtain a first background light intensity signal and a second background light intensity signal through a reference gas, and control the test light beam that generates interference fringes to obtain an absorption light intensity signal through a gas to be tested.

[0126] In addition, an embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the gas detection method described in the above method embodiment are executed.

[0127] The computer program product of the gas detection method provided in the embodiment of the present application includes a computer-readable storage medium storing program code, and the instructions included in the program code can be used to execute the steps of the gas detection method described in the above method embodiment. For details, please refer to the above method embodiment, which will not be repeated here.

[0128] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0129] In addition, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0130] If the function is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, RandomAccess Memory), disk or optical disk and other media that can store program code. It should be noted that in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variation thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus. In the absence of more restrictions, the elements defined by the sentence "includes..." do not exclude the presence of other identical elements in the process, method, article or apparatus that includes the elements.

[0131] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0132] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A gas detection method, characterized in that: include: Controlling the test light beam to pass through the reference gas to obtain a first background light intensity signal and a second background light intensity signal, and controlling the test light beam to pass through the gas to be tested to obtain an absorption light intensity signal; wherein the first background light intensity signal and the second background light intensity signal are adjacent light intensity signals; The first background light intensity signal, the second background light intensity signal and the absorption light intensity signal are processed respectively by Fourier transform to obtain a first frequency domain array, a second frequency domain array and a third frequency domain array; Obtain a first preset number of complex numbers around the modulation frequency in the first frequency domain array to obtain a first target array; obtain a first preset number of complex numbers around the modulation frequency in the second frequency domain array to obtain a second target array; and obtain a first preset number of complex numbers around the modulation frequency in the third frequency domain array to obtain a third target array; Acquire a second preset number of complex numbers in the first frequency domain array in order from front to back to obtain a fourth target array; acquire a second preset number of complex numbers in the second frequency domain array in order from front to back to obtain a fifth target array; and acquire a second preset number of complex numbers in the third frequency domain array in order from front to back to obtain a sixth target array; The first polynomial quotient is obtained by dividing the first target array by the fourth target array; the second polynomial quotient is obtained by dividing the second target array by the fifth target array; and the third polynomial quotient is obtained by dividing the third target array by the sixth target array; Calculate a target difference value according to a plurality of differences between the first polynomial quotient, the second polynomial quotient and the third polynomial quotient; wherein the first polynomial quotient, the second polynomial quotient and the third polynomial quotient are all arrays; Determine the measured parameter of the measured gas based on the target difference and the set relationship; The set relationship is used to characterize the relationship between the target difference and the parameter to be measured of the gas to be measured.

2. The method according to claim 1, characterized in that The first preset number is determined by the expression 2(m*n)+1; wherein m and n are both positive integers; The second preset number is m.

3. The method according to claim 1, characterized in that The calculating the target difference value according to a plurality of differences between the first polynomial quotient, the second polynomial quotient and the third polynomial quotient comprises: Subtracting the third polynomial quotient from the first polynomial quotient to obtain a first intermediate array; After taking the absolute value of each element in the first intermediate array, summing up the absolute values ​​to obtain a first value; Subtracting the first polynomial quotient from the second polynomial quotient to obtain a second intermediate array; After taking the absolute value of each element in the second intermediate array, summing up the absolute values ​​to obtain a second value; The first value is subtracted from the second value to obtain the target difference.

4. The method according to any one of claims 1 to 3, characterized in that: Before controlling the test light beam to pass through the reference gas to obtain the first background light intensity signal and the second background light intensity signal, and controlling the test light beam to pass through the gas to be tested to obtain the absorption light intensity signal, the method further includes: modulating the test beam; The modulated test beam passes through the set environment to generate corresponding interference fringes; The controlling the test light beam to pass through the reference gas to obtain a first background light intensity signal and a second background light intensity signal, and the controlling the test light beam to pass through the gas to be tested to obtain an absorption light intensity signal, comprises: The test light beam generating interference fringes is controlled to obtain a first background light intensity signal and a second background light intensity signal through a reference gas, and the test light beam generating interference fringes is controlled to obtain an absorption light intensity signal through a gas to be tested.

5. The method according to any one of claims 1 to 3, characterized in that: in, The reference gas is nitrogen, and the gas to be tested is ammonia.

6. The method according to any one of claims 1 to 3, characterized in that: The determination of the measured parameter of the measured gas based on the target difference and the set relationship is achieved by the following relationship: Y = kx + b; Among them, Y is the target difference, x is the parameter to be measured, k is the coefficient, and b is the constant.

7. A TDLAS system, characterized in that: Includes: laser driver, laser, gas chamber, photodetector, modulation acquisition module and electronic equipment; The input end of the laser driver is connected to the modulation acquisition module, and the output end of the laser driver is connected to the input end of the laser; the laser driver is configured to drive the laser; The laser is configured to generate a test beam, and the gas chamber is configured to contain a reference gas or a gas to be tested; wherein the beam emitted by the laser passes through the gas chamber and is received by the photodetector; The output end of the photoelectric detector is connected to the input end of the modulation acquisition module; The electronic device is connected to one or more of the laser driver, the laser, the gas chamber, the photodetector, and the modulation acquisition module; Wherein, the electronic device is configured to execute the gas detection method described in any one of claims 1-5 above.

8. A gas detection device, characterized in that: include: A control module, controlling the test light beam to pass through the reference gas to obtain a first background light intensity signal and a second background light intensity signal, and controlling the test light beam to pass through the gas to be tested to obtain an absorption light intensity signal; wherein the first background light intensity signal and the second background light intensity signal are adjacent light intensity signals; A calculation module, used to process the first background light intensity signal, the second background light intensity signal and the absorption light intensity signal respectively by Fourier transform to obtain a first frequency domain array, a second frequency domain array and a third frequency domain array; The calculation module is further used to obtain a first preset number of complex numbers around the modulation frequency in the first frequency domain array to obtain a first target array; obtain a first preset number of complex numbers around the modulation frequency in the second frequency domain array to obtain a second target array; and obtain a first preset number of complex numbers around the modulation frequency in the third frequency domain array to obtain a third target array; obtain a second preset number of complex numbers in the first frequency domain array in a forward-to-backward order to obtain a fourth target array; obtain a second preset number of complex numbers in the second frequency domain array in a forward-to-backward order to obtain a fifth target array; and obtain a second preset number of complex numbers in the third frequency domain array in a forward-to-backward order to obtain a sixth target array; obtain the first polynomial quotient by dividing the first target array by the fourth target array; obtain the second polynomial quotient by dividing the second target array by the fifth target array; and obtain the third polynomial quotient by dividing the third target array by the sixth target array; The calculation module is further used to calculate a target difference value according to a plurality of differences between the first polynomial quotient, the second polynomial quotient and the third polynomial quotient; wherein the first polynomial quotient, the second polynomial quotient and the third polynomial quotient are all arrays; A determination module is used to determine the parameter to be measured of the gas to be measured based on the target difference and a set relationship; wherein the set relationship is used to characterize the relationship between the target difference and the parameter to be measured of the gas to be measured.

9. An electronic device, characterized in that: include: A processor and a memory, wherein the memory stores machine-readable instructions executable by the processor, and when the electronic device is running, the machine-readable instructions are executed by the processor to perform the steps of any method according to claim 1 to 6.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of any one of the methods described in claims 1 to 6 are executed.

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