A dual-wavelength adaptive methane detection method and system

Abstract

The present application relates to the technical field of gas detection, and particularly relates to a dual-wavelength adaptive methane detection method and system, which comprises the following steps: collecting the environmental interference characteristics of a to-be-detected gas environment in real time; synchronously emitting a first laser beam and a second laser beam to the to-be-detected gas environment according to a tunable laser source; receiving the optical signals of the first laser beam and the second laser beam and converting them into electrical signals; calculating the light intensity difference value of the first laser beam and the second laser beam based on the electrical signals to generate a differential absorption signal; performing optical differential compensation on the differential absorption signal and outputting a methane concentration value, and performing environmental drift compensation on the methane concentration value based on the environmental interference characteristics; and performing real-time threshold judgment on the methane concentration value, and triggering a local warning signal if the methane concentration value exceeds a preset threshold. Through the present application, the problem of detection precision decline caused by the fact that the dust concentration and temperature and humidity interference cannot synchronously inhibit the common-mode noise of the methane absorption signal and the absorption coefficient drift in the dynamic and complex environment under the mine is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of gas detection technology, and in particular to a dual-wavelength adaptive methane detection method and system. Background Technology

[0002] In the field of optical gas concentration detection, tunable laser absorption spectroscopy (TEL) technology detects components by analyzing the attenuation characteristics of a specific wavelength of laser light passing through the gas to be tested. Traditional dual-wavelength differential detection methods, which combine a fixed reference wavelength with an absorption wavelength and utilize the difference between the two signals to eliminate common-mode interference, have become the mainstream solution for methane detection.

[0003] However, in complex industrial environments where dust and temperature / humidity are dynamically coupled, existing technologies face fundamental limitations: First, fixed reference wavelengths cannot synchronously adapt to the mixed interference characteristics of dust scattering and temperature / humidity drift. When drastic changes in dust concentration trigger Mie scattering, the spectral region containing the reference wavelength may simultaneously experience nonlinear attenuation, leading to differential signal failure. Second, the broadening of gas molecule absorption peaks and competitive absorption effects caused by temperature and humidity changes result in a systematic shift in the absorption coefficient, while existing methods rely on single optical differential compensation, lacking a correction mechanism for drift in molecular physical properties. Third, the dynamic changes in scattering modes caused by the multi-scale distribution of dust cause nonlinear waveform distortion in light intensity attenuation, which traditional linear compensation models struggle to effectively correct. These shortcomings lead to a significant increase in measurement errors in existing systems under complex operating conditions, severely restricting the reliability of critical scenarios such as mine safety monitoring.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the general background of this disclosure and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] This invention provides a dual-wavelength adaptive methane detection method and system, which can effectively solve the problems in the background art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A dual-wavelength adaptive methane detection method, the method comprising:

[0008] Real-time acquisition of environmental interference characteristics of the gas environment to be measured, including dust concentration and temperature and humidity;

[0009] A tunable laser source synchronously emits a first laser beam and a second laser beam into the gas environment to be tested. The wavelength of the first laser beam matches the absorption spectral peak of methane, and the wavelength of the second laser beam dynamically matches the environmental interference characteristics.

[0010] Receive the optical signals of the first laser beam and the second laser beam after passing through the gas environment to be tested, and convert the optical signals into electrical signals;

[0011] Based on the electrical signal, the intensity difference between the first laser beam and the second laser beam is calculated to generate a differential absorption signal;

[0012] The differential absorption signal is optically differentially compensated and a methane concentration value is output. The methane concentration value is then compensated for environmental drift based on the environmental interference characteristics.

[0013] The methane concentration value is judged in real time, and if it exceeds the preset threshold, a local early warning signal is triggered.

[0014] Furthermore, the wavelength of the second laser beam dynamically matches the environmental interference characteristics, including:

[0015] The dominant interference features in the gas environment under test are identified based on real-time spectral analysis.

[0016] When a single interfering component in the environmental interference features is the dominant interfering feature, the wavelength of the second laser beam is configured to the continuous spectral region between the characteristic absorption peaks of the corresponding interfering component, and the continuous spectral region satisfies that the interference signal intensity is lower than the methane detection baseline.

[0017] When the dust concentration and the temperature and humidity together dominate the interference, the wavelength of the second laser beam is configured to a wavelength region where the dust scattering effect and the water vapor absorption effect have opposite trends, and the wavelength region satisfies the requirement of minimizing the interference fluctuation amplitude.

[0018] Further, calculating the intensity difference between the first laser beam and the second laser beam based on the electrical signal to generate a differential absorption signal includes:

[0019] Time-division multiplexing and demodulation are performed on the electrical signal to separate the first pulse current signal corresponding to the first laser beam and the second pulse current signal corresponding to the second laser beam;

[0020] The first pulse current signal is converted into a first voltage value representing the intensity of the first laser beam, and the second pulse current signal is converted into a second voltage value representing the intensity of the second laser beam.

[0021] The differential amplifier performs a real-time subtraction operation between the first voltage value and the second voltage value to generate the differential absorption signal, which characterizes the separation effect between methane absorption features and environmental interference.

[0022] Further, performing time-division multiplexing demodulation on the electrical signal includes:

[0023] The modulation frequency signal generated by the tunable laser source is obtained from the electrical signal as a demodulation reference;

[0024] A first reference frequency signal synchronized with the first laser beam and a second reference frequency signal synchronized with the second laser beam are generated based on the modulation frequency signal.

[0025] The first pulse current signal is separated by synchronizing the first reference frequency signal with the electrical signal, and the second pulse current signal is separated by synchronizing the second reference frequency signal with the electrical signal.

[0026] Further, optical differential compensation is performed on the differential absorption signal and a methane concentration value is output, including:

[0027] An environmental interference baseline signal is generated based on the dynamic matching characteristics of the wavelength of the second laser beam, wherein the dynamic matching characteristics include executing wavelength configuration rules based on the dominant interference features;

[0028] Calculate the real-time scaling factor between the differential absorption signal and the environmental interference baseline signal to separate common-mode interference;

[0029] The real-time proportional coefficient is nonlinearly corrected based on the dust concentration in the environmental disturbance characteristics to compensate for the shift in light scattering characteristics caused by differences in dust particle size distribution.

[0030] The corrected real-time scaling factor and the wavelength absorption intensity parameter of the first laser beam are subjected to absorption feature enhancement operation to generate a feature enhancement signal that is monotonically related to the methane concentration and convert it into the methane concentration value.

[0031] The wavelength absorption intensity parameter is a physical quantitative characterization of the degree of light intensity attenuation after the first laser beam penetrates the gas environment under test.

[0032] Furthermore, an environmental interference baseline signal is generated based on the dynamic matching characteristics of the wavelength of the second laser beam, including:

[0033] Based on the dust concentration and temperature and humidity in the environmental interference characteristics, the wavelength configuration rule is executed to determine the target wavelength of the second laser beam;

[0034] The tunable laser source is controlled to adjust the wavelength of the second laser beam to the target wavelength;

[0035] Receive the optical signal of the second laser beam after it has passed through the gas environment to be tested, and convert the optical signal into a second voltage value;

[0036] The intensity value of the second laser beam at the target wavelength is obtained from the second voltage value and used as the environmental interference baseline signal.

[0037] Furthermore, nonlinear correction is performed on the real-time proportional coefficient based on the dust concentration in the environmental disturbance characteristics, including:

[0038] The current scattering mode characteristics are determined based on the dust concentration, and the scattering mode characteristics are characterized by the ratio of the forward scattered light intensity to the back scattered light intensity of the dual-wavelength laser.

[0039] Based on the scattering mode characteristics, the distortion type of the optical signal caused by the dust particle size is identified, and the distortion type includes uniform attenuation type and nonlinear distortion type;

[0040] Based on the distortion type, a corresponding signal compensation mechanism is selected. If it is the uniform attenuation type, the real-time proportional coefficient is enhanced according to the backscattered light intensity ratio.

[0041] If it is a nonlinear distortion type, then waveform inversion compensation is performed on the real-time scaling factor.

[0042] Further, the corrected real-time scaling factor is combined with the wavelength absorption intensity parameter of the first laser beam to perform absorption feature enhancement operation, including:

[0043] A signal enhancement operation is performed based on the real-time scaling factor and the wavelength absorption intensity parameter to generate a characteristic enhanced signal, wherein the signal enhancement operation establishes a monotonic correlation between the methane-related absorption component in the wavelength absorption intensity parameter and the methane concentration.

[0044] The methane concentration value is output by performing signal conversion based on the concentration conversion relationship of the feature enhancement signal, wherein the concentration conversion relationship is the corresponding correlation between the feature enhancement signal and the methane concentration.

[0045] Furthermore, environmental drift compensation is performed on the methane concentration value based on the aforementioned environmental disturbance characteristics, including:

[0046] Based on the temperature and humidity in the environmental disturbance characteristics, the drift of methane molecule absorption characteristics is determined, and an environmental drift correction factor is generated, wherein the drift of methane molecule absorption characteristics characterizes the shift in methane absorption coefficient caused by the changes in temperature and humidity.

[0047] The environmental drift correction factor is applied to the methane concentration value to correct the concentration measurement deviation caused by the drift of the methane molecule absorption characteristics, and the corrected methane concentration value is output.

[0048] A dual-wavelength adaptive methane detection system, the system comprising:

[0049] The information acquisition module collects environmental interference characteristics of the gas environment under test in real time, including dust concentration and temperature and humidity.

[0050] The dual-wave emission module synchronously emits a first laser beam and a second laser beam to the gas environment under test based on a tunable laser source. The wavelength of the first laser beam matches the absorption spectrum peak of methane, and the wavelength of the second laser beam dynamically matches the environmental interference characteristics.

[0051] The signal conversion module receives the optical signals from the first and second laser beams after passing through the gas environment under test, and converts the optical signals into electrical signals.

[0052] The differential calculation module calculates the intensity difference between the first laser beam and the second laser beam based on the electrical signal to generate a differential absorption signal;

[0053] The concentration compensation module performs optical differential compensation on the differential absorption signal and outputs the methane concentration value, and performs environmental drift compensation on the methane concentration value based on environmental interference characteristics.

[0054] The detection and early warning module performs real-time threshold judgment on methane concentration values. If the value exceeds the preset threshold, a local early warning signal is triggered.

[0055] The technical solution of this invention can achieve the following technical effects:

[0056] It effectively solves the problem of decreased detection accuracy caused by the inability to simultaneously suppress common-mode noise and absorption coefficient drift of methane absorption signals in the dynamic and complex environment of underground mines due to the interference of dust concentration and temperature and humidity.

[0057] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0058] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0059] Figure 1 This is a schematic diagram of a process for a dual-wavelength adaptive methane detection method;

[0060] Figure 2 A schematic diagram of the process for generating a differential absorption signal;

[0061] Figure 3 A schematic diagram of the process for optical differential compensation;

[0062] Figure 4 A schematic diagram of the process for environmental drift compensation. Detailed Implementation

[0063] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0065] Example 1;

[0066] like Figure 1 As shown, this application provides a dual-wavelength adaptive methane detection method, the method comprising:

[0067] Real-time acquisition of environmental interference characteristics of the gas environment to be measured, including dust concentration and temperature and humidity;

[0068] Based on the synchronous emission of a first laser beam and a second laser beam from a tunable laser source into the gas environment to be tested, the wavelength of the first laser beam is matched to the absorption spectrum peak of methane, and the wavelength of the second laser beam is dynamically matched to the environmental interference characteristics.

[0069] It receives the optical signals from the first and second laser beams after they pass through the gas environment under test, and converts the optical signals into electrical signals;

[0070] A differential absorption signal is generated based on the intensity difference between the first and second laser beams calculated using electrical signals.

[0071] Optical differential compensation is performed on the differential absorption signal and the methane concentration value is output. Environmental drift compensation is also performed on the methane concentration value based on environmental interference characteristics.

[0072] The methane concentration value is judged in real time, and if it exceeds the preset threshold, a local warning signal is triggered.

[0073] Specifically, firstly, the environmental interference characteristics of the gas under test are collected in real time. Preferably, a high-precision environmental sensor module can be set up to acquire the dust concentration and temperature and humidity data of the actual environment. The environmental sensor module can include independent dust sensors and temperature and humidity sensors, and the detected parameters are input to the signal processing module through a data acquisition card to ensure that the environmental interference characteristics can reflect the actual situation of the gas under test in real time. In addition, to improve detection efficiency, the sensor module is preferably installed close to the area to be tested, and a shielding cover is used to effectively reduce external interference to ensure the stability and accuracy of data acquisition. Secondly, based on the synchronous emission of a first laser beam and a second laser beam from a tunable laser source, this design uses two independent and frequency-stable laser sources. The emission wavelength of the first laser beam is locked to the peak wavelength of the methane absorption spectrum, for example, a wavelength around 1.65 micrometers is precisely selected to match the main absorption characteristics of methane. At the same time, the wavelength of the second laser beam is based on the real-time acquisition. The environmental interference characteristics are adjusted within a specified dynamic matching range. The dynamic wavelength adjustment is preferably based on temperature and humidity changes, and the wavelength is adjusted in real time through a laser tuning module to most accurately reflect the influence of the environment on the measurement. Two laser beams are combined into a composite laser beam through an optical path coupler, and after calibration, they are synchronously introduced into the gas environment to be measured. Subsequently, in the preferred embodiment, the optical signal reception and conversion process can be carried out using a high-sensitivity photodetector to receive the first and second laser beams after passing through the gas environment to be measured. The photodetector can be set to a dual-channel structure to simultaneously and independently acquire the two optical signals, converting the received optical signals into corresponding electrical signals. In order to reduce the possible interference from other light sources when receiving signals, specially designed filtering components, such as bandpass filters, can be installed to accurately identify optical signals of each wavelength and limit other non-target optical signals from entering the detector. Then, the light intensity difference between the two laser electrical signals is calculated and a differential absorption signal is generated.In the preferred embodiment, a signal processor, such as an FPGA or digital signal processor, performs real-time calculations. This processor employs a time synchronization algorithm to ensure that the intensity difference between the two laser signals accurately reflects the actual methane concentration characteristics. After the differential absorption signal is generated, it enters an optical differential compensation module. This module compensates for the differential signal by adjusting baseline stability and optical path deviation, ensuring that the error caused by signal fluctuations is within a controllable range. Furthermore, this module preferably incorporates a temperature and humidity-related compensation model to perform reward-based optimization against environmental interference, thereby improving the accuracy of methane concentration detection. Further, based on the obtained differential absorption signal, the current methane concentration value is output through a methane concentration calculation model. This calculation model is preferably based on a preset methane absorption spectrum database and is corrected by combining actual environmental drift compensation values. The drift compensation values ​​can be obtained from the real-time acquisition... The dust concentration and temperature and humidity parameters are input into the calculation model and dynamically adjusted. To ensure the reliability of the output data, a redundant detection mechanism can be added, such as repeatedly calculating the concentration of multiple samples from different areas. When the consistency of the concentration values ​​reaches a set threshold, the final methane concentration value is output. Finally, after outputting the methane concentration value, real-time threshold judgment of the concentration value is an indispensable part of the preferred implementation scheme. The concentration value is compared with the preset safety threshold by a threshold comparator on a time period. If the concentration value exceeds the set safety threshold, a local early warning signal or linkage alarm system is triggered. In the preferred design, the local early warning includes audible and visual alarms, warning light illumination, notification platform, etc. At the same time, the system can be further integrated with a data transmission module to upload the concentration value to the monitoring cloud, which facilitates real-time data monitoring and advanced alarm processing.

[0074] The technical solution of this invention effectively solves the problem of decreased detection accuracy caused by the inability to simultaneously suppress common-mode noise and absorption coefficient drift of methane absorption signals in the dynamic and complex environment of mines due to the interference of dust concentration and temperature and humidity.

[0075] Furthermore, the wavelength dynamic matching environmental interference characteristics of the second laser beam include:

[0076] Identify the dominant interference features in the gas environment under test based on real-time spectral analysis;

[0077] When a single interference component is the dominant interference feature in the environmental interference characteristics, the wavelength of the second laser beam is configured to be in the continuous spectral region between the characteristic absorption peaks of the corresponding interference component, and the continuous spectral region satisfies that the interference signal intensity is lower than the methane detection baseline.

[0078] When dust concentration and temperature and humidity jointly dominate the interference, the wavelength of the second laser beam is configured to the wavelength region where the dust scattering effect and water vapor absorption effect produce opposite trends, and the wavelength region satisfies the requirement of minimizing the interference fluctuation amplitude.

[0079] As a preferred embodiment of the above, firstly, spectral information of the environment under test is acquired in real time to identify the spectral absorption characteristic peaks adjacent to methane. Based on this, dominant interference features, such as dust concentration, water vapor absorption, and temperature and humidity changes, are extracted from the spectral data of the environment under test. The core of this process lies in the ability to dynamically determine the main types of interference affecting the accuracy of methane detection based on real-time spectral data, thereby providing a basis for subsequent wavelength adjustment. To further achieve dynamic wavelength matching based on interference features, when the dominant interference feature is a single interference component, such as single-component water vapor interference or single-component dust interference, this embodiment preferably adjusts the wavelength of the second laser beam... The wavelength is adjusted to a continuous spectral region corresponding to the absorption peaks of interfering components where interference is relatively weak. This continuous spectral region has two characteristics: first, its interference signal intensity is significantly lower than the methane detection baseline, effectively reducing methane detection error; second, through in-depth analysis of spectral data, this region is ensured to be sufficiently stable to reduce the fluctuation of the detection results caused by interference. Simultaneously, to ensure the accuracy of wavelength adjustment, the laser source is fine-tuned in real time to match the changes of a single interfering component in the test environment. If the dominant interfering factor in the test environment cannot be determined by a single component, but is simultaneously affected by changes in dust concentration and temperature and humidity, this embodiment preferably adopts another wavelength selection method. Formula: The wavelength of the second laser beam is adjusted to a wavelength region where the dust scattering effect and the water vapor absorption effect exhibit opposite trends. This wavelength region is selected and optimized to ensure that the fluctuations in the detection signal caused by dust scattering cancel each other out with the fluctuations in the water vapor absorption characteristics, thereby minimizing the amplitude of interference signal fluctuations. The implementation process of this wavelength selection strategy includes the following three parts: First, through an independent calibration module, the dynamic change patterns of the dust scattering effect and the water vapor absorption effect are identified; second, based on data modeling technology, the characteristic spectral regions with opposite trends are fitted to determine the wavelength optimization scheme; third, the laser beam is adjusted in real time according to the fitting results to accurately position it to the pre-selected wavelength range. Wavelength range; for example, in practical applications, when water vapor absorption and dust concentration in the environment jointly affect methane detection, the interference characteristics of the two are identified by the spectral analysis module. It is found that the dust scattering effect is mainly concentrated in a shorter wavelength range, such as 1.3 micrometers to 1.4 micrometers, while the water vapor absorption effect is broad-spectrum absorption and more significant in a longer wavelength range, such as 1.8 micrometers to 2.0 micrometers. After finding that the changing trends of the two are complementary, it is preferable to adjust the wavelength of the second laser beam to a region where the effects of the two are relatively balanced, such as the wavelength range of 1.6 micrometers to 1.7 micrometers, thereby effectively reducing the fluctuation of the interference of the two.

[0080] Furthermore, such as Figure 2 As shown, the differential absorption signal is generated by calculating the intensity difference between the first and second laser beams based on electrical signals, including:

[0081] Time-division multiplexing and demodulation are performed on the electrical signal to separate the first pulse current signal corresponding to the first laser beam and the second pulse current signal corresponding to the second laser beam;

[0082] The first pulse current signal is converted into a first voltage value characterizing the intensity of the first laser beam, and the second pulse current signal is converted into a second voltage value characterizing the intensity of the second laser beam.

[0083] The differential amplifier performs a real-time subtraction operation between the first voltage value and the second voltage value to generate a differential absorption signal that characterizes the separation effect between methane absorption features and environmental interference.

[0084] As a preferred embodiment of the above, firstly, a first laser beam and a second laser beam from a dual-wavelength laser source illuminate the area to be measured, respectively. A photodetector receives the corresponding light intensities of the two laser beams in the environment and generates a time-specific electrical signal. This electrical signal includes pulse current signals corresponding to the first and second laser beams, respectively. In this embodiment, time-division multiplexing technology is used to demodulate the received electrical signal, separating it into two independent signals: a first pulse current signal representing the first laser beam and a second pulse current signal representing the second laser beam. Time-division multiplexing improves signal processing efficiency while reducing the complexity of the system's synchronization requirements. Next, the current signal is transmitted through a current circuit... The voltage conversion circuit processes the signals, converting the first pulse current signal into a corresponding first voltage value and the second pulse current signal into a corresponding second voltage value. In this conversion process, this embodiment preferably uses a high-precision operational amplifier for signal processing to ensure that the voltage values ​​accurately represent the real-time light intensity of each laser beam and to suppress errors caused by detector noise. Furthermore, to avoid the influence of high environmental interference signals on the conversion accuracy, this embodiment adds a filtering module to the circuit board design and uses a low-pass filter to remove high-frequency noise. After obtaining the first and second voltage values, this embodiment uses a differential amplifier to perform real-time subtraction on the two voltage values ​​to generate differential absorption. The selection of the signal and differential amplifier is one of the key technologies in this embodiment. A differential amplifier with a high common-mode rejection ratio is preferred to ensure that the influence of interference signals on the detection results can be effectively suppressed when methane absorption signals and environmental interference signals coexist. Simultaneously, the gain coefficient of the differential amplifier is precisely calibrated to achieve high-sensitivity signal extraction. In this embodiment, the real-time subtraction operation directly generates a differential absorption signal, which characterizes the absorption characteristics of methane molecules within a specific wavelength range and effectively separates environmental interference from the detection results. This differential absorption signal can be further input into the back-end processing via the data acquisition system for in-depth interpretation of methane concentration. For example, assuming the environment... In the presence of dust interference and with a low methane concentration, the first laser beam is selected to target the methane absorption peak region, for example, 1.65 micrometers, while the second laser beam is selected to target a continuous spectrum region with low dust interference, for example, 1.50 micrometers. The pulsed current signals received and generated by the photodetector are time-division multiplexed and demodulated into a first pulsed current signal and a second pulsed current signal, respectively. These two sets of current signals are then converted into voltage values ​​representing light intensity. The difference between the two signals is calculated in real time using a configured differential amplifier to generate a differential absorption signal reflecting the methane detection signal. After further analysis and processing, this signal can be used to monitor the methane concentration in real time, while automatically eliminating the influence of environmental dust interference, thereby achieving accurate methane detection.

[0085] Furthermore, performing time-division multiplexing and demodulation on electrical signals includes:

[0086] The modulation frequency signal generated by the tunable laser source is obtained from the electrical signal as the demodulation reference;

[0087] A first reference frequency signal synchronized with the first laser beam and a second reference frequency signal synchronized with the second laser beam are generated based on the modulation frequency signal.

[0088] The first pulse current signal is separated by synchronizing the first reference frequency signal with the electrical signal to obtain the first pulse current signal, and the second pulse current signal is separated by synchronizing the second reference frequency signal with the electrical signal to obtain the second pulse current signal.

[0089] As a preferred embodiment of the above, firstly, the photodetector used in this embodiment receives an electrical signal from a dual-wavelength laser beam. This electrical signal is a composite signal of the periodic switching of the two laser beams, including pulse signals corresponding to the first and second laser beams respectively. To accurately separate these two signals, this embodiment preferably extracts modulation parameters from the modulation frequency signal generated by the tunable laser source as a demodulation reference. This modulation frequency signal can characterize the synchronous switching rate and switching characteristics of the first and second laser beams. This reference signal is provided by the signal generation module inside the laser source and cooperates with the subsequent demodulation circuit through a digital interface. Next, this embodiment is based on the modulation frequency... Two reference frequency signals are generated: a first reference frequency signal synchronized with the first laser beam and a second reference frequency signal synchronized with the second laser beam. The generation of these reference signals is achieved using an optimized signal processing unit. This unit processes the modulation frequency signal using phase-locked loop (PLL) technology to ensure that the reference signal accurately reflects the modulation characteristics and switching time of the laser beam. This optimized reference signal generation process reduces jitter and frequency deviation in practical applications, further ensuring high-precision signal control. To separate the first and second pulse current signals from the electrical signal, this embodiment employs phase-synchronous demodulation technology. The specific operation is as follows: the first reference frequency signal is synchronized with the electrical signal... The first laser beam pulse signal is synchronously modulated to demodulate the first laser beam pulse signal and separate the first pulse current signal. Simultaneously, the second reference frequency signal is synchronously modulated with the electrical signal to demodulate the second laser beam pulse signal and separate the second pulse current signal. A preferred approach is to incorporate a high dynamic range synchronization control module in the demodulation unit to ensure close time matching between the reference signal and the signal to be demodulated, reducing signal loss due to phase errors during demodulation. For example, assuming the laser beam modulation frequency in a certain application scenario is 10kHz, the reference frequency distribution generated by the demodulation reference modulation signal is the first laser beam synchronization signal (5kHz) and the second laser beam synchronization signal (5kHz). The first reference frequency signal (5kHz, offset 180 degrees) is received by the photodetector as a combination of the two electrical signals. Each signal cycle carries methane detection data and environmental interference information. After generating a synchronization reference signal using phase-locked loop technology, the demodulation circuit performs a high-sensitivity phase comparison operation between the first reference frequency signal and the original electrical signal to separate the pulse current signal associated with the first laser beam in the time sequence. Similarly, by combining the second reference frequency signal with the original electrical signal, the second pulse current signal can also be accurately separated. This technology ensures that the pulse signal data to be acquired is synchronized with the reference signal and eliminates interference noise caused by signal switching.

[0090] Furthermore, such as Figure 3 As shown, optical differential compensation is performed on the differential absorption signal and the methane concentration value is output, including:

[0091] An environmental interference baseline signal is generated based on the dynamic matching characteristics of the second laser beam's wavelength. The dynamic matching characteristics include the execution of wavelength configuration rules based on the dominant interference features.

[0092] Calculate the real-time scaling factor between the differential absorbed signal and the environmental interference baseline signal to separate common-mode interference;

[0093] Nonlinear correction is performed on the real-time proportional coefficient based on the dust concentration in the environmental disturbance characteristics to compensate for the shift in light scattering characteristics caused by the difference in dust particle size distribution.

[0094] The corrected real-time scaling factor and the wavelength absorption intensity parameter of the first laser beam are subjected to absorption feature enhancement operation to generate a feature enhancement signal that is monotonically related to the methane concentration and convert it into a methane concentration value.

[0095] The wavelength absorption intensity parameter is a physical quantitative characterization of the degree of light intensity attenuation after the first laser beam penetrates the gas environment under test.

[0096] As a preferred embodiment of the above, firstly, an environmental interference baseline signal is generated based on the dynamic matching characteristics of the second laser beam wavelength. To achieve dynamic matching, a wavelength configuration rule that dominates the real-time changes of interference characteristics is selected according to the real-time spectral analysis results. For example, when identifying dust concentration or water vapor absorption effect as the dominant interference, the continuous spectral region with the smallest interference fluctuation is selected as the wavelength range of the second laser beam. Through real-time dynamic wavelength adjustment, a stable environmental interference baseline signal is obtained to generate a background light intensity characterization signal with stable function. Secondly, the acquired differential absorption signal and the environmental interference baseline signal are compared in real-time to achieve common-mode interference separation. Preferably, signal processing is used through automatic... Gain control technology adapts the extraction of the proportional gain, thereby optimizing the separation process of environmental signals and methane detection information. During the real-time calculation of the proportional gain, it analyzes the characteristic differences between the environmental baseline signal and the differential absorption signal, stripping away the amplitude portion of common-mode interference, allowing the residual signal to directly reflect the methane absorption characteristics. Next, to compensate for optical deviations caused by differences in dust concentration and particle size distribution, this embodiment performs nonlinear correction on the real-time proportional gain. Preferably, it analyzes the influence of dust concentration on light scattering effects within different particle size ranges. For example, finer dust particles are more likely to cause scattering attenuation near the laser wavelength, while coarser dust particles have relatively weaker scattering effects. Nonlinear correction is then applied to address this. The positive model quantifies the influence of dust on light intensity as a deviation parameter and applies compensation calculations to the proportionality coefficient, ultimately generating a corrected proportionality coefficient to eliminate the offset interference of light scattering characteristics. After obtaining the corrected proportionality coefficient, this embodiment further combines the wavelength absorption intensity parameter of the first laser beam to perform absorption feature enhancement. The wavelength absorption intensity parameter is determined by the quantitative physical characteristics reflected by the light intensity attenuation phenomenon of the first laser beam after penetrating the gas environment under test. The absorption degree of methane molecules to a specific wavelength beam can be characterized by the ratio of energy attenuation. In the absorption feature enhancement module, a feature enhancement signal is generated by linearly enhancing the calibrated proportionality coefficient and the wavelength absorption intensity parameter. A digital signal processing unit with precise gain control is used to jointly evaluate and optimize the intensity of different characteristic signals to ensure that the generated feature enhancement signal can fully retain the methane absorption characteristics while further weakening the influence of environmental interference. Finally, the feature enhancement signal is converted into a methane concentration value. By pre-calibrating various complex interference environments, this embodiment preferably uses database comparison technology to establish a standard model of spectral absorption characteristics under different environmental conditions. The corrected feature enhancement signal is compared with the standard model in the database. The scheme calculates the final output value directly corresponding to the methane concentration through interpolation or fitting methods. The methane concentration value can be accurately presented to the user in digital form.

[0097] Furthermore, an environmental interference baseline signal is generated based on the dynamic matching characteristics of the second laser beam's wavelength, including:

[0098] Based on the dust concentration and temperature and humidity characteristics in the environmental interference, wavelength configuration rules are executed to determine the target wavelength of the second laser beam;

[0099] The wavelength of the second laser beam is adjusted to the target wavelength by controlling the tunable laser source;

[0100] It receives the optical signal of the second laser beam after it passes through the gas environment to be tested, and converts the optical signal into a second voltage value;

[0101] The light intensity value of the second laser beam at the target wavelength is obtained from the second voltage value as the environmental interference baseline signal.

[0102] As a preferred embodiment of the above, firstly, this embodiment determines the target wavelength of the second laser beam by executing wavelength configuration rules based on the dust concentration and temperature and humidity data in the real-time measured environmental interference characteristics. To achieve this process, environmental parameters of the area to be measured are continuously collected, including dust concentration, particle size distribution, air humidity, and temperature changes. Preferably, a dynamic decision-making algorithm based on multivariate analysis is used to input the above parameters into the environmental feature model and calculate the influence degree of the current dominant interference component. For example, when the temperature and humidity are high and the dust particle size is concentrated in a small range, an optimal wavelength range that can balance water vapor absorption and dust scattering effects is selected as the target wavelength based on the results. Next, the tunable laser source is controlled to adjust the wavelength of the second laser beam to the target wavelength. This embodiment preferably uses a high-precision tunable laser source, whose internal fine-tuning control system can adjust the laser wavelength output in real time by inputting the target wavelength command. The specific adjustment process of the light source is completed through a feedback loop, that is, after wavelength adjustment, the laser beam is used to adjust the wavelength of the second laser beam to the target wavelength. The wavelength monitor verifies whether the output wavelength is consistent with the calculation rules, ensuring the accuracy of the target wavelength and avoiding over-adjustment, further improving the stability and robustness of the system. After the adjusted second laser beam passes through the gas environment under test, it will be affected by the dominant interference characteristics in the environment, such as dust, temperature and humidity, and its light intensity will be attenuated accordingly. In this embodiment, the light signal of the second laser beam is received by a high-sensitivity photodetector, and the received light signal is converted into a second voltage value through a current-to-voltage conversion circuit. In view of the low-frequency fluctuation of the signal caused by environmental interference, the acquisition circuit is further optimized. By embedding noise suppression and digital filtering technology in the photodetector, the signal stability is improved and noise interference is effectively suppressed to ensure that the second voltage value can accurately characterize the light intensity characteristics of the laser beam after passing through the environment. In order to finally generate the environmental interference baseline signal, this embodiment extracts the light intensity value of the second laser beam at the target wavelength from the second voltage value to characterize the interference of the current environment under test. The specific extraction process is completed through the data processing module, including a preprocessing step to remove outliers and a specific calibration process for light intensity values ​​based on the target wavelength range. It is preferable to dynamically update the baseline signal, that is, to continuously record the fluctuations in light intensity signal caused by environmental changes in real time measurement, and to establish a dynamic baseline model based on this. This dynamic model can not only reflect the transient characteristics of environmental interference, but also support differential comparison with the methane concentration detection signal, providing data support for accurate separation and compensation of interference.

[0103] Furthermore, nonlinear correction is performed on the real-time proportional coefficient based on the dust concentration in the environmental disturbance characteristics, including:

[0104] The current scattering mode characteristics are determined based on the dust concentration, and the scattering mode characteristics are characterized by the ratio of the forward scattered light intensity to the back scattered light intensity of the dual-wavelength laser.

[0105] Based on the scattering mode characteristics, the distortion type of the optical signal caused by the dust particle size is identified. The distortion types include uniform attenuation type and nonlinear distortion type.

[0106] The corresponding signal compensation mechanism is selected based on the type of distortion. If it is a uniform attenuation type, the real-time proportional coefficient is enhanced according to the ratio of backscattered light intensity.

[0107] If it is a nonlinear distortion type, then waveform inversion compensation is performed on the real-time scaling factor.

[0108] As a preferred embodiment of the above, this embodiment first employs a high-sensitivity photoelectric detection device. By detecting the forward and backscattered light intensities in the dual-wavelength laser beam, the scattering pattern characteristics within the current dust concentration area are determined. Specifically, the forward scattered light intensity represents the energy of the beam continuing to propagate forward after penetrating dust particles, while the backscattered light intensity directly reflects the proportion of energy reflected back by the beam due to scattering by dust particles. The photoelectric detector converts the scattered light intensity signal into an electrical signal and, combined with the light intensity ratio calculation module, generates the ratio of forward to backscattered light from the dual-wavelength laser beam to characterize the scattering pattern characteristics of the beam by dust particles. In the preferred embodiment, the ratio calculation dynamic adjustment module can track the scattering pattern in real time. The variation in dust concentration and scattering affects the stability and real-time performance of the scattering mode characteristics. Next, this embodiment identifies the distortion type of the optical signal caused by dust particle size based on the scattering mode characteristics. The distortion types mainly include uniform attenuation and nonlinear distortion. These two types have different mechanisms of influence on the real-time scaling factor. In uniform attenuation, the light intensity is less affected by the dust particle size distribution, and the scattering characteristics of the dual-wavelength laser change linearly with dust concentration. However, in nonlinear distortion, when the particle size range is wide or the dust distribution is uneven, the optical signal is prone to complex distortion phenomena, including amplitude nonlinear attenuation and waveform distortion. This embodiment uses a distortion analysis module to input the scattering mode characteristics into a classification algorithm to identify the impact of dust on the optical signal in the current dust environment. The specific types of influence on the optical signal; after identifying the distortion type caused by the dust particle size environment, the embodiment selects the corresponding signal compensation mechanism to correct the real-time scaling factor. If the distortion type is confirmed to be uniform attenuation type, the real-time scaling factor is enhanced based on the backscattered light intensity data, so that the energy part of the backscattered signal is amplified and compensated, thereby achieving global signal correction for the standard particle size region in the dust environment. The compensation mechanism specifically includes weighted processing of the backscattered light signal and dynamic adjustment of the compensation parameters by comparing the attenuation model of the characteristic light intensity signal through the calibration module, ensuring that the compensation result can accurately reflect the true attenuation state of the beam environment; if the distortion type is nonlinear distortion type, this embodiment uses the waveform inversion compensation method to correct the real-time signal. The proportional coefficient is corrected. The nonlinear distortion compensation technology is based on the identified waveform distortion types, including phase shift and non-uniform clipping. The inverse calculation module generates an inverse waveform processing signal to cancel the distortion components in the signal. For example, when the forward scattered light signal exhibits non-uniform spikes, the inverse processing module generates a matching inverse cancellation waveform for the spike signal. The two are superimposed to restore the true proportional coefficient signal. The specific steps of inverse compensation include establishing a waveform feature model, defining the degree of distortion, and selecting the optimal compensation parameters through database comparison and analysis. In addition, this embodiment introduces a feedback adjustment mechanism in the waveform compensation stage to verify the correction process of the compensation signal in real time, ensuring the accuracy and response stability of the proportional coefficient after correction.

[0109] Furthermore, the absorption characteristic enhancement operation is performed on the corrected real-time scaling factor and the wavelength absorption intensity parameter of the first laser beam, including:

[0110] Signal enhancement operations are performed based on real-time scaling factor and wavelength absorption intensity parameters to generate characteristic enhanced signals. The signal enhancement operation establishes a monotonic correlation between the methane-related absorption component in the wavelength absorption intensity parameters and the methane concentration.

[0111] The methane concentration value is output by signal conversion based on the concentration conversion relationship of the feature enhancement signal and the methane concentration.

[0112] As a preferred embodiment of the above, firstly, this embodiment performs signal enhancement based on the corrected real-time scaling factor and the wavelength absorption intensity parameter of the first laser beam to generate a characteristic enhanced signal. The real-time scaling factor, after correction in the previous steps, characterizes the compensation amount for particle interference. This factor reflects the actual impact correction of the dominant environmental interference on the laser signal. The wavelength absorption intensity parameter of the first laser beam specifically describes the absorption characteristics of methane at that laser wavelength. To achieve the signal enhancement operation, this embodiment preferably employs an absorption component enhancement algorithm. This algorithm correlates the real-time scaling factor with the light intensity attenuation of the first laser beam, and filters out non-methane interference factors by dynamically enhancing the methane absorption component signal. For example, a known high absorption wavelength, such as the methane absorption peak at 1.65 micrometers, is selected as the key data processing area. The absorption intensity change trend is extracted and the methane characteristic signal is amplified. At the same time, background noise signals related to dust scattering or water vapor absorption are weakened. A multi-level gain control mechanism is adopted to adjust the gain amplitude so that the enhanced absorption component signal exhibits monotonic characteristics with the methane concentration in the data expression. Next, this embodiment converts the generated characteristic enhanced signal with the concentration conversion... The system performs signal conversion to ultimately output methane concentration values. The concentration conversion relationship is a mathematical model established through experimental calibration in the initial stage of the system. It reflects the corresponding correlation between the characteristic enhancement signal and the actual methane concentration. To ensure accuracy, this embodiment uses high-precision instruments to measure actual methane concentration data under different environmental interference conditions, combined with characteristic signal changes for fitting training. For example, by establishing a multivariate linear fitting or nonlinear curve fitting model, each enhancement signal interval is directly mapped to the methane concentration value. In specific operation, the characteristic enhancement signal is input into the model for real-time calculation, and numerical concentration data is generated through the concentration conversion module. In addition, this embodiment achieves accurate enhancement of methane detection signals in dynamic environments through enhancement operations. In the preferred design, the enhancement algorithm also includes a dynamic adjustment function, that is, when the concentration fluctuates drastically or the environmental interference changes, the gain parameters and conversion model are automatically updated to adapt to the detection needs under different environments. For example, when a surge in temperature and humidity causes large-scale fluctuations in the detection signal, the enhancement strategy and conversion relationship are quickly refitted through a feedback mechanism to achieve smooth and real-time data output of methane concentration.

[0113] Furthermore, such as Figure 4 As shown, environmental drift compensation for methane concentration values ​​based on environmental disturbance characteristics includes:

[0114] Based on temperature and humidity in the environmental disturbance characteristics, the drift of methane molecule absorption characteristics is determined, and an environmental drift correction factor is generated. The drift of methane molecule absorption characteristics represents the shift of methane absorption coefficient caused by changes in temperature and humidity.

[0115] An environmental drift correction factor is applied to the methane concentration value to correct the concentration measurement deviation caused by the drift due to the absorption characteristics of methane molecules, and the corrected methane concentration value is output.

[0116] As a preferred embodiment of the above, environmental parameters of temperature and humidity are collected, influencing factors that may cause drift in methane absorption characteristics are analyzed, and the concentration measurement results are corrected in real time. At the start of methane detection, environmental temperature and humidity data of the area to be measured are continuously collected using temperature and humidity sensors. Through physical models or experimental calibration, the drift of temperature and humidity on the methane molecule absorption coefficient is generated. These drifts characterize the comprehensive influence of environmental changes on the wavelength shift, absorption coefficient change rate, and absorption intensity of the methane absorption peak. For example, as the temperature rises, the position of the methane molecule absorption peak will shift slightly towards the longer wavelength direction. At the same time, the increase in humidity may enhance the absorption characteristics of nearby water vapor, thereby affecting the methane signal. All of the above factors need to be included in the drift calculation. This embodiment preferably adopts a correction factor generation technology based on multivariate influencing factors to convert the drift caused by changes in temperature and humidity in the environment into an environmental drift correction factor. The specific steps include: inputting the currently detected temperature and humidity data into the drift calculation, and analyzing the changing law of methane absorption characteristics under different temperature and humidity conditions through an embedded quantitative model, and generating a set of correction factor models through calibration data; parameter changes in real-time environmental reading will drive the adjustment of the current value of the correction factor to ensure The generated correction factor can dynamically adapt to environmental changes. Environmental conditions exceeding the calibration range will trigger an external database call for supplementation. Accuracy can be ensured even in complex scenarios such as extreme high temperature or humid environments. Subsequently, the generated environmental drift correction factor is applied to the current output methane concentration value to comprehensively correct the concentration deviation caused by the drift of methane molecule absorption characteristics. The correction process is completed by a real-time computing unit: first, the original concentration value and the environmental drift correction factor are calculated step by step to eliminate the influence of the environment on the absorption intensity; then, it is evaluated whether the corrected concentration data conforms to the calibration range of the wavelength absorption model to ensure that the final output result can reflect the actual methane concentration. It is preferable to set a threshold detection to monitor the drift amount and the range of the correction factor in real time to avoid the problem of decreased measurement accuracy caused by exceeding the calibration limit. In addition, under complex environmental conditions, this embodiment also establishes a dynamic adjustment strategy for the correction factor. When a drastic change in the environment is detected, such as a sudden increase or decrease in temperature, the impact of the sudden change in the environment will be analyzed first and the drift amount will be updated in real time. For long-term monitoring, the correction factor can be automatically optimized to match the periodic environmental change trend to avoid the problem of long-term distortion of detection data due to continuous environmental shift.

[0117] Example 2;

[0118] Based on the same inventive concept as the dual-wavelength adaptive methane detection method in the foregoing embodiments, the present invention also provides a dual-wavelength adaptive methane detection system, the system comprising:

[0119] The information acquisition module collects environmental interference characteristics of the gas environment under test in real time, including dust concentration and temperature and humidity.

[0120] The dual-wave emission module synchronously emits a first laser beam and a second laser beam to the gas environment under test based on a tunable laser source. The wavelength of the first laser beam matches the absorption spectrum peak of methane, and the wavelength of the second laser beam dynamically matches the environmental interference characteristics.

[0121] The signal conversion module receives the optical signals from the first and second laser beams after passing through the gas environment under test, and converts the optical signals into electrical signals.

[0122] The differential calculation module calculates the intensity difference between the first laser beam and the second laser beam based on the electrical signal to generate a differential absorption signal;

[0123] The concentration compensation module performs optical differential compensation on the differential absorption signal and outputs the methane concentration value, and performs environmental drift compensation on the methane concentration value based on environmental interference characteristics.

[0124] The detection and early warning module performs real-time threshold judgment on methane concentration values. If the value exceeds the preset threshold, a local early warning signal is triggered.

[0125] The adjustment system described above in this invention can effectively realize a dual-wavelength adaptive methane detection method, and the technical effects it can achieve are as described in the above embodiments, which will not be repeated here.

[0126] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of the application as defined herein, and are to be considered as covering any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Thus, if such modifications and modifications fall within the scope of this application and its equivalents, this application intends to include such modifications and modifications.

Claims

1. A method for detecting methane based on dual-wavelength adaptive methane, characterized in that, The method includes: Real-time acquisition of environmental interference characteristics of the gas environment to be measured, including dust concentration and temperature and humidity; A tunable laser source synchronously emits a first laser beam and a second laser beam into the gas environment to be tested. The wavelength of the first laser beam matches the absorption spectral peak of methane, and the wavelength of the second laser beam dynamically matches the environmental interference characteristics. Receive the optical signals of the first laser beam and the second laser beam after passing through the gas environment to be tested, and convert the optical signals into electrical signals; Based on the electrical signal, the intensity difference between the first laser beam and the second laser beam is calculated to generate a differential absorption signal; The differential absorption signal is optically differentially compensated and a methane concentration value is output. The methane concentration value is then compensated for environmental drift based on the environmental interference characteristics. The methane concentration value is judged in real time, and if it exceeds the preset threshold, a local early warning signal is triggered. Performing optical differential compensation on the differential absorption signal and outputting the methane concentration value includes: An environmental interference baseline signal is generated based on the dynamic matching characteristics of the second laser beam's wavelength. These dynamic matching characteristics include executing wavelength configuration rules based on dominant interference features. The wavelength configuration rules include continuously collecting environmental parameters of the area under test, including dust concentration, particle size distribution, air humidity, and temperature changes. A dynamic decision-making algorithm based on multivariate analysis is used to input these environmental parameters into an environmental feature model and calculate the influence of the current dominant interference component. An optimal wavelength range that balances water vapor absorption and dust scattering effects is selected as the target wavelength; or the continuous spectrum region with the least interference fluctuation is selected as the wavelength range of the second laser beam. Calculate the real-time scaling factor between the differential absorption signal and the environmental interference baseline signal to separate common-mode interference; The real-time proportional coefficient is nonlinearly corrected based on the dust concentration in the environmental disturbance characteristics to compensate for the shift in light scattering characteristics caused by differences in dust particle size distribution. The corrected real-time scaling factor and the wavelength absorption intensity parameter of the first laser beam are subjected to absorption feature enhancement operation to generate a feature enhancement signal that is monotonically related to the methane concentration and convert it into the methane concentration value. The wavelength absorption intensity parameter is a physical quantitative characterization of the degree of light intensity attenuation after the first laser beam penetrates the gas environment under test. An environmental interference baseline signal is generated based on the dynamic matching characteristics of the wavelength of the second laser beam, including: Based on the dust concentration and temperature and humidity in the environmental interference characteristics, the wavelength configuration rule is executed to determine the target wavelength of the second laser beam; The tunable laser source is controlled to adjust the wavelength of the second laser beam to the target wavelength; Receive the optical signal of the second laser beam after it has passed through the gas environment to be tested, and convert the optical signal into a second voltage value; The intensity value of the second laser beam at the target wavelength is obtained from the second voltage value and used as the environmental interference baseline signal.

2. The dual-wavelength adaptive methane detection method according to claim 1, characterized in that, The wavelength of the second laser beam dynamically matches the environmental interference characteristics, including: The dominant interference features in the gas environment under test are identified based on real-time spectral analysis. When a single interfering component in the environmental interference features is the dominant interfering feature, the wavelength of the second laser beam is configured to the continuous spectral region between the characteristic absorption peaks of the corresponding interfering component, and the continuous spectral region satisfies that the interference signal intensity is lower than the methane detection baseline. When the dust concentration and the temperature and humidity together dominate the interference, the wavelength of the second laser beam is configured to a wavelength region where the dust scattering effect and the water vapor absorption effect have opposite trends, and the wavelength region satisfies the requirement of minimizing the interference fluctuation amplitude.

3. The dual-wavelength adaptive methane detection method according to claim 1, characterized in that, Based on the electrical signal, the intensity difference between the first laser beam and the second laser beam is calculated to generate a differential absorption signal, including: Time-division multiplexing and demodulation are performed on the electrical signal to separate the first pulse current signal corresponding to the first laser beam and the second pulse current signal corresponding to the second laser beam; The first pulse current signal is converted into a first voltage value representing the intensity of the first laser beam, and the second pulse current signal is converted into a second voltage value representing the intensity of the second laser beam. The differential amplifier performs a real-time subtraction operation between the first voltage value and the second voltage value to generate the differential absorption signal, which characterizes the separation effect between methane absorption features and environmental interference.

4. The dual-wavelength adaptive methane detection method according to claim 3, characterized in that, Performing time-division multiplexing demodulation on the electrical signal includes: The modulation frequency signal generated by the tunable laser source is obtained from the electrical signal as a demodulation reference; A first reference frequency signal synchronized with the first laser beam and a second reference frequency signal synchronized with the second laser beam are generated based on the modulation frequency signal. The first pulse current signal is separated by synchronizing the first reference frequency signal with the electrical signal, and the second pulse current signal is separated by synchronizing the second reference frequency signal with the electrical signal.

5. The dual-wavelength adaptive methane detection method according to claim 1, characterized in that, Nonlinear correction is performed on the real-time proportional coefficient based on the dust concentration in the environmental disturbance characteristics, including: The current scattering mode characteristics are determined based on the dust concentration, and the scattering mode characteristics are characterized by the ratio of the forward scattered light intensity to the back scattered light intensity of the dual-wavelength laser. Based on the scattering mode characteristics, the distortion type of the optical signal caused by the dust particle size is identified, and the distortion type includes uniform attenuation type and nonlinear distortion type; Based on the distortion type, a corresponding signal compensation mechanism is selected. If it is the uniform attenuation type, the real-time proportional coefficient is enhanced according to the backscattered light intensity ratio. If it is a nonlinear distortion type, then waveform inversion compensation is performed on the real-time scaling factor.

6. The dual-wavelength adaptive methane detection method according to claim 1, characterized in that, The absorption feature enhancement operation is performed on the corrected real-time scaling factor and the wavelength absorption intensity parameter of the first laser beam, including: A signal enhancement operation is performed based on the real-time scaling factor and the wavelength absorption intensity parameter to generate a characteristic enhanced signal, wherein the signal enhancement operation establishes a monotonic correlation between the methane-related absorption component in the wavelength absorption intensity parameter and the methane concentration. The methane concentration value is output by performing signal conversion based on the concentration conversion relationship of the feature enhancement signal, wherein the concentration conversion relationship is the corresponding correlation between the feature enhancement signal and the methane concentration.

7. The dual-wavelength adaptive methane detection method according to claim 1, characterized in that, Environmental drift compensation for the methane concentration value based on the aforementioned environmental disturbance characteristics includes: Based on the temperature and humidity in the environmental disturbance characteristics, the drift of methane molecule absorption characteristics is determined, and an environmental drift correction factor is generated, wherein the drift of methane molecule absorption characteristics characterizes the shift in methane absorption coefficient caused by the changes in temperature and humidity. The environmental drift correction factor is applied to the methane concentration value to correct the concentration measurement deviation caused by the drift of the methane molecule absorption characteristics, and the corrected methane concentration value is output.

8. A dual-wavelength adaptive methane detection system, characterized in that, The system includes: The information acquisition module collects environmental interference characteristics of the gas environment under test in real time, including dust concentration and temperature and humidity. The dual-wave emission module synchronously emits a first laser beam and a second laser beam to the gas environment under test based on a tunable laser source. The wavelength of the first laser beam matches the absorption spectrum peak of methane, and the wavelength of the second laser beam dynamically matches the environmental interference characteristics. The signal conversion module receives the optical signals from the first and second laser beams after passing through the gas environment under test, and converts the optical signals into electrical signals. The differential calculation module calculates the intensity difference between the first laser beam and the second laser beam based on the electrical signal to generate a differential absorption signal; The concentration compensation module performs optical differential compensation on the differential absorption signal and outputs the methane concentration value, and performs environmental drift compensation on the methane concentration value based on environmental interference characteristics. The detection and early warning module performs real-time threshold judgment on methane concentration values. If the value exceeds the preset threshold, a local early warning signal is triggered.

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