A gas detection method based on resonance fusion of acoustic wave signals and photoacoustic signals

Abstract

This invention discloses a gas detection method based on the resonant fusion of acoustic and photoacoustic signals, belonging to the field of gas detection technology. The method constructs a resonant photoacoustic cell containing an acoustic excitation unit, an acoustic sensor, and an extinction-absorbing flange. First, the system's acoustic resonant frequency is determined and a stable, phase-tunable sound field is established. Then, a tunable laser is driven to emit a co-modulated light-excited photoacoustic signal. Phase feedback control achieves precise superposition of the two signal peaks. After acquiring the fused signal, it undergoes reverberation détente using FFT and LMS algorithms, as well as synchronous compression processing via wavelet transform. Combined with an established calibration model, the gas component and concentration are detected. This invention utilizes dual-modal resonant fusion to significantly enhance the measurement signal, improving the signal-to-noise ratio. While simplifying the signal acquisition and processing modules and achieving a lightweight detection system, it also enhances anti-interference capabilities and reduces the complexity and difficulty of high-sensitivity detection systems for trace gases in complex environments.

Description

Technical Field

[0001] This invention relates to the field of gas detection technology, and more specifically, to a gas detection method based on the resonant fusion of acoustic and photoacoustic signals. Background Technology

[0002] Gas detection technology has research and application value in many fields such as environmental monitoring, industrial control, and biomedicine. Among them, photoacoustic spectroscopy has become one of the mainstream technologies for trace gas detection due to its high specificity, high sensitivity, and extremely low detection limit. This technology works by modulating a laser to irradiate the gas to be tested. The gas molecules absorb the light energy and undergo periodic thermal expansion and contraction, which excites an acoustic signal (i.e., a photoacoustic signal). The intensity of the signal is proportional to the gas concentration, and the gas concentration is then inverted by detecting the signal intensity.

[0003] However, in traditional photoacoustic spectroscopy gas detection technology, the original photoacoustic signal generated by the absorption of trace gases is extremely weak and easily submerged by environmental noise and system electronic noise, resulting in a low signal-to-noise ratio. To extract this weak signal from the noise, existing technologies typically rely on complex hardware enhancement schemes, such as using optical multi-pass cells to increase the optical path, using high-power lasers to increase the excitation energy, or using external lock-in amplifiers for filtering. While these measures can improve the signal to some extent, they also lead to problems such as large system size, high cost, and complex optical debugging, making it difficult to achieve lightweight design. Secondly, this technology essentially relies on a single photoacoustic signal channel, and its signal quality is susceptible to interference from light source fluctuations, window contamination, optical collimation misalignment, and complex acoustic environments (such as airflow noise and vibration), posing challenges to long-term stability and reliability in complex application scenarios such as field and online environments.

[0004] Therefore, in response to the above problems, this patent proposes a gas detection method based on the resonant fusion of acoustic and photoacoustic signals. It aims to improve signal strength and system anti-interference capability through a dual-modal coherent enhancement mechanism, thereby reducing dependence on high-cost and high-complexity hardware and achieving lightweight, highly stable, and highly sensitive gas detection. Summary of the Invention

[0005] The purpose of this invention is to provide a gas detection method based on the resonant fusion of acoustic and photoacoustic signals, which addresses the shortcomings of existing technologies and solves the problems mentioned in the background.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A gas detection method based on the resonant fusion of acoustic and photoacoustic signals includes the following steps: S1. Constructing a resonant photoacoustic detection module: The photoacoustic detection module includes a resonant photoacoustic cell with a built-in acoustic excitation unit and acoustic sensor. The resonant photoacoustic cell is equipped with an air inlet and an air outlet. One end of the resonant photoacoustic cell is equipped with an extinction and sound-absorbing flange. The resonant photoacoustic cell is externally connected to a tunable laser, a tunable signal source, a tunable laser controller, a signal acquisition circuit, a control and calculation module, and a display unit. The gas to be tested is introduced into the resonant photoacoustic cell to ensure that the gas inside the cell is completely replaced. S2. The acoustic resonant frequency of the detection system is determined by driving an adjustable signal source to track and determine the frequency sweep method. f w At the same time, with frequency f w Drive the acoustic excitation unit to generate a frequency of f w High-amplitude, continuous, and phase-controllable sound waves are used to establish a phase-tunable sound field within the detection system. S3. Drive the tunable laser using a tunable laser controller to make the wavelength of the emitted laser beam match the center wavelength of the absorption line of the gas under test, and make the laser modulation frequency the same as the frequency of the phase-tunable sound field. f w The modulated laser is incident into the resonant photoacoustic cell, which excites the gas molecules to be tested to generate photoacoustic signals. S4. While maintaining the phase-tunable sound field, the phase of the phase-tunable sound field is monitored in real time through the phase feedback control loop. The phase of the sound wave excitation unit is finely adjusted so that the peak of the phase-tunable sound field is superimposed on the peak of the photoacoustic signal to achieve coherent superposition and form a fused signal. The fused signal is directly acquired by the acoustic sensor and transmitted to the signal acquisition circuit. S5. Based on the fused signal, the control and calculation modules perform FFT processing and remove reverberation interference to identify or quantify the components and concentrations in the gas to be measured.

[0007] Furthermore, the matte sound-absorbing flange includes a porous sound-absorbing material layer and a matte coating applied to the surface of the matte sound-absorbing flange.

[0008] Furthermore, the phase-tunable sound field is a continuous sine wave.

[0009] Furthermore, the signal fusion after phase synchronization in step S4 follows the principle of vector coherent superposition:

[0010] in, To fuse signal amplitude, For photoacoustic signals, It is a sound wave signal. To maximize the acousto-optic coupling coefficient, This represents the phase difference.

[0011] Furthermore, in step S5, the least mean square error algorithm is used to remove reverberation interference, based on the driving signal of the acoustic excitation unit. x(n) For reference, the non-resonant multipath effect in the acoustic path is modeled from the acquired mixed signals. d(n) The estimated reverberation interference component is subtracted from the output to obtain the de-reverberation fused signal.

[0012] Furthermore, information on the components of the gas to be measured is determined based on the fused signal, including: extracting the spectral and time-frequency features of the fused signal; Based on spectral and time-frequency characteristics, the concentration of the gas component to be measured is obtained by inversion through the established calibration model.

[0013] Furthermore, the extraction of spectral features from the fused signal includes performing a Fast Fourier Transform on the fused signal to obtain its spectrum.

[0014] Furthermore, the extraction of time-frequency features from the fused signal includes: performing synchronous compression processing of wavelet transform on the transformed signal to obtain a high-resolution time-frequency representation, and extracting features from it.

[0015] Furthermore, the method for constructing the calibration model includes: collecting fusion signals generated by various standard gases of known concentrations under gas detection methods, extracting the spectral features obtained by fast Fourier transform and the time-frequency features obtained by synchronous compressed wavelet transform of the fusion signals to construct a feature dataset, and obtaining the calibration model based on the feature dataset and its corresponding known concentration values.

[0016] The present invention has at least the following advantages or beneficial effects: This invention creatively introduces active acoustic excitation into a photoacoustic detection system. It establishes a high-amplitude, stable, phase-controllable sound field synchronized with the system's acoustic resonant frequency within the detection cavity, serving as a physical "carrier." When a weak photoacoustic signal of the same frequency excited by a modulated laser is superimposed in phase with the precisely controlled, phase-tunable sound field, they undergo constructive interference according to the principle of vector coherent superposition. This resonant fusion process directly amplifies the amplitude of the weak photoacoustic signal within the acoustic cavity to the optimal linear detection range of the acoustic sensor, achieving physical pre-amplification of the signal. Therefore, this method reduces the reliance on high-power light sources, complex multi-channel optical paths, or high-gain lock-in amplifiers found in traditional technologies, simplifies the system hardware structure, and provides a new approach to achieving lightweight, low-cost, and miniaturized detection systems.

[0017] Furthermore, since the signal-to-noise ratio of the fused signal is linearly improved compared to the single photoacoustic signal, the system's ability to suppress random noise and common-mode interference in the environment is significantly enhanced. Combined with reverberation removal and spectral and time-frequency feature extraction algorithms on the acquired signal, environmental interference can be further eliminated, accurately pinpointing the signal characteristics generated by the analyte gas. This dual-modal signal fusion and collaborative processing mechanism reduces the complexity and difficulty of high-sensitivity detection systems for trace gases in complex environments, providing an innovative technical solution for the development of gas detection technology. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic flowchart of a gas detection method based on the resonant fusion of acoustic and photoacoustic signals, provided in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the system structure of a gas detection method based on the resonant fusion of acoustic and photoacoustic signals, provided in an embodiment of the present invention.

[0021] Icons: 1. Tunable laser; 2. Resonant photoacoustic cell; 3. Air inlet; 4. Acoustic excitation unit; 5. Acoustic sensor; 6. Air outlet; 7. Extinction sound-absorbing flange; 8. Signal acquisition circuit; 9. Control and calculation module; 10. Adjustable signal source; 11. Tunable laser controller; 12. Display unit. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] This invention addresses the problems of weak signals, heavy reliance on complex hardware (such as lock-in amplifiers and multi-pass cells) leading to system lightweighting in traditional photoacoustic spectroscopy gas detection technologies, and the weak anti-interference capability of single signal channels in complex environments. It proposes an innovative dual-modal resonant fusion detection scheme. This method is applicable to scenarios requiring high sensitivity and high stability for trace gas detection in environmental monitoring, industrial process control, safety early warning, and biomedicine. Its core idea lies in actively establishing a high-amplitude, stable, phase-controllable acoustic field synchronized with the system's acoustic resonant frequency within the detection cavity. By precisely controlling its phase and coherently superimposing it with a weak photoacoustic signal of the same frequency generated by laser excitation, physical pre-amplification of the signal and a significant improvement in the signal-to-noise ratio are achieved. This fundamentally reduces the dependence on high-gain amplification circuitry at the backend, making it possible to construct lightweight, high-performance gas sensors.

[0024] Please refer to Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a gas detection method based on the resonant fusion of acoustic and photoacoustic signals, comprising the following steps: S1. Constructing a resonant photoacoustic detection module: The photoacoustic detection module includes a resonant photoacoustic cell with a built-in acoustic excitation unit and acoustic sensor. The resonant photoacoustic cell is equipped with an air inlet and an air outlet. One end of the resonant photoacoustic cell is equipped with an extinction and sound-absorbing flange. The resonant photoacoustic cell is externally connected to a tunable laser, a tunable signal source, a tunable laser controller, a signal acquisition circuit, a control and calculation module, and a display unit. The gas to be tested is introduced into the resonant photoacoustic cell to ensure that the gas inside the cell is completely replaced. S2. The acoustic resonant frequency of the detection system is determined by driving an adjustable signal source to track and determine the frequency sweep method. f w At the same time, with frequency f w Drive the acoustic excitation unit to generate a frequency of f w High-amplitude, continuous, and phase-controllable sound waves are used to establish a phase-tunable sound field within the detection system. S3. Drive the tunable laser using a tunable laser controller to make the wavelength of the emitted laser beam match the center wavelength of the absorption line of the gas under test, and make the laser modulation frequency the same as the frequency of the phase-tunable sound field. f w The modulated laser is incident into the resonant photoacoustic cell, which excites the gas molecules to be tested to generate photoacoustic signals. S4. While maintaining the phase-tunable sound field, the phase of the phase-tunable sound field is monitored in real time through the phase feedback control loop. The phase of the sound wave excitation unit is finely adjusted so that the peak of the phase-tunable sound field is superimposed on the peak of the photoacoustic signal to achieve coherent superposition and form a fused signal. The fused signal is directly acquired by the acoustic sensor and transmitted to the signal acquisition circuit. S5. Based on the fused signal, the control and calculation modules perform FFT processing and remove reverberation interference to identify or quantify the components and concentrations in the gas to be measured.

[0025] In this embodiment, step S1, constructing the resonant photoacoustic detection module, is specifically executed as follows: [The text abruptly ends here, likely due to an incomplete sentence or a formatting error.] Figure 2 The detection system shown is a photoacoustic detection module. The core of the module is a resonant photoacoustic cell 2, which integrates an acoustic excitation unit 4 and an acoustic sensor 5. The acoustic excitation unit 4 is a loudspeaker, and the acoustic sensor 5 is a microphone. The resonant photoacoustic cell 2 has an inlet 3 and an outlet 6 for the introduction and discharge of the gas to be tested. An matting sound-absorbing flange 7 is installed at one end of the photoacoustic cell 2 (usually the opposite end to the laser incident end). The matting sound-absorbing flange 7 can be designed to include a porous sound-absorbing material layer and a matting coating applied to its surface. The porous sound-absorbing material layer adjusts the acoustic impedance at the boundary of the photoacoustic cell to match the target resonant mode, thereby optimizing the resonance effect. It also absorbs sound energy at non-resonant frequencies, suppresses unnecessary standing waves and resonances, and reduces acoustic reverberation interference. The matting coating on the surface efficiently absorbs incident laser scattering, preventing light from re-entering the optical path after diffuse reflection at the cell wall or generating additional photoelectric noise, ensuring the purity and efficiency of the excitation photoacoustic signal.

[0026] The resonant photoacoustic detection module is externally connected to a tunable laser 1 as a light source, a signal acquisition circuit 8 for acquiring and initially processing sensor signals, a control and calculation module 9 as the core processing unit, an adjustable signal source 10 for generating electrical drive signals, a tunable laser controller 11 for controlling the laser's operation, and a display unit 12 for displaying results. The signal acquisition circuit 8 is electrically connected to the acoustic sensor 5 and to the control and calculation module 9. The control and calculation module 9 is signal-connected to the adjustable signal source 10, and also to the display unit 12 and the tunable laser controller 11. The adjustable signal source 10 is signal-connected to the acoustic excitation unit 4.

[0027] Before starting the test, the gas to be tested is continuously introduced into the resonant photoacoustic cell 2 through the air inlet 3 to ensure that the original gas in the cell is completely replaced, thereby ensuring that the object of the test is the current gas sample. The construction of the resonant photoacoustic detection module provides a physical carrier and hardware foundation for the subsequent generation, fusion and acquisition of acoustic and optical dual-modal signals.

[0028] In this embodiment, step S2 involves driving an adjustable signal source to track and determine the acoustic resonant frequency of the detection system using a frequency sweep method. f w The specific process is as follows: After system initialization, the control and calculation module 9 controls the adjustable signal source 10 to output a frequency sweep signal with continuously varying frequency (e.g., linear or logarithmic sweep from low frequency to high frequency). This signal drives the acoustic excitation unit 4 to generate a frequency sweep sound wave within the resonant photoacoustic cell 2. Simultaneously, the acoustic sensor 5 collects the sound pressure response signal within the cell in real time and transmits it back to the signal acquisition circuit 8. The control and calculation module 9 performs a fast Fourier transform analysis on the collected response signal to find the peak point in the amplitude response spectrum. The frequency corresponding to this peak point is the acoustic resonance frequency of the resonant photoacoustic cell 2 under the current gas composition, temperature, and pressure conditions. f w Determine the frequency. f w Subsequently, the control and calculation module 9 instructs the adjustable signal source 10 to lock the output frequency to [value missing]. f w Furthermore, each measurement requires frequency sweeping to determine the resonant frequency in the current environment, reducing environmental interference to the system. As a preferred implementation, the adjustable signal source 10 generates a frequency of... f w A continuous sinusoidal signal is generated and drives the acoustic excitation unit 4 to operate. Since the driving signal is a continuous and fixed-frequency sinusoidal wave, the acoustic excitation unit 4 can excite and maintain a high-amplitude, time-stable, continuously phase-tunable sound field within the resonant photoacoustic cell 2. This steady-state sound field serves as the coherent sound source for subsequent signal fusion. The system monitors the phase difference between this sound field and the photoacoustic signal, dynamically tuning the frequency and phase of the driving sound source to ensure that the sound field actively maintains strict synchronization with the photoacoustic signal.

[0029] In this embodiment, in step S3, based on the characteristic absorption spectral lines of the target component of the gas to be tested, the control and calculation module 9 instructs the tunable laser 1 via the tunable laser controller 11 to precisely tune the center wavelength of its output laser to the peak wavelength of the absorption line, ensuring that the laser energy is efficiently absorbed by the gas molecules to be tested. Simultaneously, the control and calculation module 9 uses the acoustic resonance frequency determined in step S2... f w The modulation frequency parameter is sent to the tunable laser controller 11. The tunable laser controller 11 then modulates the frequency... f w The output light intensity of the laser is sinusoidally modulated. The intensity-modulated laser light enters the resonant photoacoustic cell 2 through an optical window. The gas molecules in the cell absorb the light energy and generate periodic heat release, forming an alternating heat source, thereby exciting a frequency that is similar to the modulation frequency. f wThe same sound wave, i.e., the photoacoustic signal. This step ensures that the photoacoustic signal and the phase-tunable sound field are completely identical in frequency, satisfying the basic condition for subsequent coherent fusion.

[0030] In this embodiment, step S4 is specifically executed as follows: While maintaining the phase-tunable sound field established in step S2 and the synchronously modulated laser generated in step S3, the system initiates a digital or analog phase feedback control loop implemented by the control and calculation module 9. This loop uses the signal collected in real-time by the acoustic sensor 5 as the feedback input. First, the control and calculation module 9 extracts the real-time phase information of the phase-tunable sound field component from this signal. Then, this real-time phase is compared with a set target phase (usually corresponding to the peak position of the photoacoustic signal) to calculate the phase difference. The control and calculation module 9 generates a small phase correction value based on the phase difference, and fine-tunes the driving phase of the phase-tunable sound field generated by the acoustic excitation unit 4 by dynamically adjusting the initial phase of the driving signal sent to the tunable signal source 10. The purpose of this closed-loop control process is to ensure that the peak of the controlled sound field and the photoacoustic signal generated by laser excitation achieve strict phase synchronization when they propagate to the location of the acoustic sensor 5. In this embodiment, the signal fusion after phase synchronization strictly follows the principle of vector coherent superposition:

[0031] in, To fuse signal amplitude, For photoacoustic signals, It is a sound wave signal. To maximize the acousto-optic coupling coefficient ( ), The phase difference. When maximizing the acousto-optic coupling coefficient. Approaching 1, and the phase difference The system is in a coherent resonance state, and the synthesized amplitude reaches At its maximum value, the signal-to-noise ratio (SNR) of the fused signal is linearly improved compared to the single photoacoustic signal. The acoustic sensor 5 directly acquires this significantly enhanced fused signal and converts it into an electrical signal, which is then transmitted to the signal acquisition circuit 8. This process physically amplifies the signal, greatly reducing the gain requirements of the back-end circuitry and significantly improving the SNR of the original signal.

[0032] In this embodiment, in step S5, the signal acquisition circuit 8 filters and performs analog-to-digital conversion on the analog fusion signal transmitted by the acoustic sensor 5 to obtain a mixed signal. d(n) Then, the control and calculation module 9 processes the digital signal. This processing mainly includes two core sub-steps: removing reverberation interference and performing concentration inversion based on spectral and time-frequency characteristics.

[0033] The reverberation interference removal sub-step employs an adaptive filtering algorithm, such as the minimum mean square error (LMS) algorithm. This algorithm uses a known driving signal to drive the acoustic excitation unit 4. x(n) As a reference input, the non-resonant multipath effects in the acoustic path are modeled from the acquired mixed signal. d(n) The estimated reverberation interference component is subtracted from the output signal, resulting in a dereverberated mixed signal that retains both the resonant acoustic wave component and the photoacoustic signal component. This process effectively removes deterministic interference introduced by the system's own acoustic characteristics, improving the accuracy of subsequent feature extraction.

[0034] After déresonance is completed, the information for determining the components of the gas to be measured based on the fused signal includes extracting spectral and time-frequency features from the déresonant fused signal to obtain its feature dataset. First, FFT is performed on the fusion result of the acoustic and photoacoustic signals to extract spectral features, and then time-frequency features are extracted from the fused signal using a wavelet transform synchronous compression algorithm.

[0035] Finally, based on the extracted spectral and time-frequency features, the concentration of the gas component to be tested is obtained through an established calibration model. The construction method of this established calibration model typically includes: collecting fused signals from multiple standard gas samples of known different concentrations; systematically extracting the aforementioned spectral and time-frequency features from these signals to construct a dedicated feature dataset; and using this feature dataset and corresponding known concentration labels as training samples, training the model using a multivariate correction algorithm to obtain a calibration model that can map input features to gas concentration values. In actual detection, the control and calculation module 9 inputs the features extracted from the fused signal of the current gas to be tested into this trained calibration model, which can quickly and accurately calculate and output the concentration value of the gas to be tested, and finally display it on the display unit 12.

[0036] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A gas detection method based on resonance fusion of acoustic wave signals and photoacoustic signals, characterized by, Includes the following steps: S1. Constructing a resonant photoacoustic detection module: The resonant photoacoustic detection module includes a resonant photoacoustic cell with a built-in acoustic excitation unit and acoustic sensor. The resonant photoacoustic cell is equipped with an air inlet and an air outlet. One end of the resonant photoacoustic cell is equipped with an extinction and sound-absorbing flange. The resonant photoacoustic cell is externally connected to a tunable laser, a tunable signal source, a tunable laser controller, a signal acquisition circuit, a control and calculation module, and a display unit. The gas to be tested is introduced into the resonant photoacoustic cell to ensure that the gas inside the cell is completely replaced. S2. The acoustic resonant frequency of the detection system is determined by driving an adjustable signal source to track and determine the frequency sweep method. f w At the same time, with frequency f w Drive the acoustic excitation unit to generate a frequency of f w High-amplitude, continuous, and phase-controllable sound waves are used to establish a phase-tunable sound field within the detection system. S3. Drive the tunable laser using a tunable laser controller to make the wavelength of the emitted laser beam match the center wavelength of the absorption line of the gas under test, and make the laser modulation frequency the same as the frequency of the phase-tunable sound field. f w The modulated laser is incident into the resonant photoacoustic cell, which excites the gas molecules to be tested to generate photoacoustic signals. S4. While maintaining the phase-tunable sound field, the phase of the phase-tunable sound field is monitored in real time through the phase feedback control loop. The phase of the sound wave excitation unit is finely adjusted so that the peak of the phase-tunable sound field is superimposed on the peak of the photoacoustic signal, achieving coherent superposition and forming a fused signal. The signal fusion after phase synchronization follows the principle of vector coherent superposition: in, To fuse signal amplitude, For photoacoustic signals, It is a sound wave signal. To maximize the acousto-optic coupling coefficient, The phase difference is used; the fused signal is directly acquired by the acoustic sensor and transmitted to the signal acquisition circuit. S5. Based on the fused signal, the control and calculation modules perform FFT processing and remove reverberation interference. The reverberation interference removal adopts the minimum mean square error algorithm, using the driving signal of the acoustic excitation unit. x(n) For reference, the non-resonant multipath effect in the acoustic path is modeled from the acquired mixed signals. d(n) The estimated reverberation interference component is subtracted from the output signal to obtain the de-reverberation fusion signal, thereby completing the identification or quantification of the components and concentrations in the gas to be tested. 2.The gas detection method based on resonance fusion of acoustic wave signals and photoacoustic signals according to claim 1, characterized in that, The matte sound-absorbing flange includes a porous sound-absorbing material layer and a matte coating applied to the surface of the matte sound-absorbing flange. 3.The gas detection method based on the resonance fusion of the acoustic wave signal and the photoacoustic signal according to claim 1, characterized in that, The phase-tunable sound field is a continuous sine wave. 4.The gas detection method based on the resonance fusion of acoustic wave signals and photoacoustic signals according to claim 1, characterized in that, Information on the components of the gas to be measured based on the fused signal includes: extracting the spectral and time-frequency features of the fused signal; Based on spectral and time-frequency characteristics, the concentration of the gas component to be measured is obtained by inversion through the established calibration model.

5. The gas detection method based on the resonant fusion of acoustic and photoacoustic signals according to claim 4, characterized in that, Extracting spectral features from the fused signal includes performing a Fast Fourier Transform on the fused signal to obtain its spectrum. 6.The gas detection method based on the resonance fusion of acoustic wave signals and photoacoustic signals according to claim 5, characterized in that, Extracting time-frequency features from the fused signal includes: performing synchronous compression processing of the transformed signal using wavelet transform to obtain a high-resolution time-frequency representation, and then extracting features from it. 7.The gas detection method based on the resonance fusion of acoustic wave signals and photoacoustic signals according to claim 6, characterized in that, The method for constructing the calibration model includes: collecting fusion signals generated by various standard gases of known concentrations under gas detection methods, extracting the spectral features obtained by fast Fourier transform and the time-frequency features obtained by synchronous compressed wavelet transform of the fusion signals to construct a feature dataset, and obtaining the calibration model based on the feature dataset and its corresponding known concentration values.

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