Vehicle-mounted holder laser telemetry scanning type gas leakage positioning system

Abstract

The invention discloses a vehicle-mounted holder laser telemetering scanning type gas leakage positioning system, and relates to the technical field of gas leakage monitoring. The vehicle-mounted pan-tilt laser telemetering scanning type gas leakage positioning system comprises a data acquisition unit for acquiring laser absorption second harmonic signal intensity of an inspection vehicle on a set route; the concentration inversion processing unit is used for inverting the gas concentration on the basis of the signal; the concentration analysis unit is used for identifying an abnormal inspection point by comparing the concentration change rate; the leakage direction analysis unit is used for predicting the leakage direction by combining wind direction concentration data; according to the invention, a signal saturation upper limit value and an optical path length value are introduced to carry out normalization processing, concentration inversion calibration is carried out in combination with a gas absorption coefficient, independent calculation is carried out at each inspection position point, and the accuracy of the inspection is greatly improved by combining remote measurement concentration distribution data, image data and a leakage position analysis unit for accurately positioning a leakage point in combination with a gas diffusion model. And continuous, dynamic and high-precision concentration distribution reconstruction in space is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of gas leakage monitoring, and particularly to a vehicle-mounted pan-tilt laser telemetry scanning gas leakage positioning system. Background Art

[0002] With the continuous advancement of urbanization, the risk of gas leakage is increasing day by day. Especially during the use of flammable and explosive gases such as natural gas, leakage incidents may bring serious safety hazards. Therefore, establishing an efficient and real-time gas leakage monitoring system has become an important task for ensuring public safety. Currently, most gas leakage monitoring systems on the market mainly rely on traditional gas sensors or chemical detection methods. These technologies generally have disadvantages such as low sensitivity, slow response speed, and being greatly affected by environmental factors, and are difficult to cope with complex and changeable monitoring environments.

[0003] Laser Absorption Spectroscopy (LAS), as an advanced technology for accurately measuring gas concentration, has gradually been applied to the field of gas leakage monitoring due to its characteristics of high sensitivity, high selectivity, and non-contact measurement. This technology can analyze the absorption signal after the interaction between a laser beam and gas molecules, and can detect the concentration change of the gas in real time and accurately, with high spatial resolution and time resolution. Although Laser Absorption Spectroscopy has great advantages in gas detection, its application in vehicle-mounted gas leakage monitoring systems still faces some challenges.

[0004] The limitations of the existing technology at least include the following problems. Traditional systems mostly rely on the gas concentration threshold alarm mechanism during the inspection process. After detecting an increase in concentration, they can only generally identify the existence of leakage, but cannot further calculate the specific spatial position of the leakage source. This way of identifying concentration anomalies lacks a directional judgment and concentration gradient analysis mechanism, resulting in a large ambiguity in the positioning result, which can only be used to trigger an alarm and is difficult to guide precise disposal. At the same time, the existing systems have not effectively introduced a gas diffusion model for inversion calculation, and it is difficult to couple and analyze the concentration data at different measurement points with environmental variables such as wind speed, wind direction, temperature, and humidity. Therefore, it is difficult to establish a logical chain for inferring the position of the leakage source from the concentration distribution. In addition, in terms of data structure, most traditional systems collect single-point data and ignore the recording of spatial coordinates and time dimensions, making it difficult to model the diffusion characteristics of the concentration evolving with position and time, which further restricts the positioning accuracy of the source point. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the present invention provides a vehicle-mounted pan-tilt laser telemetry scanning gas leakage positioning system, which solves the problem of difficult precise positioning of leakage points in the existing technology.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A vehicle-mounted pan-tilt laser telemetry scanning gas leakage positioning system, comprising: a data acquisition unit for acquiring the laser absorption second harmonic signal intensities at a plurality of inspection position points of the inspection vehicle on a set inspection route; a concentration inversion processing unit for inverting the initial concentration values of the target gas at each inspection position point based on the laser absorption second harmonic signal intensities; a concentration analysis unit for comparing the concentration change rates of the target gas between adjacent inspection position points and identifying abnormal inspection position points based on a preset concentration threshold and change rate threshold; a leakage direction analysis unit for acquiring the target gas wind direction concentration data at the abnormal inspection position points and determining the predicted leakage direction of the target gas; and a leakage position analysis unit for acquiring the telemetry concentration distribution data and image data at the predicted leakage direction of the target gas and performing a joint analysis in combination with a preset gas diffusion model to obtain the leakage point position information of the target gas.

[0007] Further, the specific steps for inverting the initial concentration values of the target gas at each inspection position point based on the laser absorption second harmonic signal intensities are as follows: Obtain the signal saturation upper limit value and the optical path length value; comprehensively analyze the laser absorption second harmonic signal intensities at each inspection position point in combination with the signal saturation upper limit value and the optical path length value respectively to obtain the initial concentration values of the target gas at each inspection position point.

[0008] Further, the specific formula for calculating the initial concentration values of the target gas at each inspection position point is as follows: ; where is the initial concentration value of the target gas at a certain inspection position point, is the laser absorption second harmonic signal intensity at a certain inspection position point, is the absorption coefficient stored in the database, is the optical path length value, is the signal saturation upper limit value.

[0009] Further, the specific steps for comparing the concentration change rates of the target gas between adjacent inspection position points and identifying abnormal inspection position points based on a preset concentration threshold and change rate threshold are as follows: Read the initial concentration values of the target gas at each inspection position point and perform an adjacent concentration change analysis to obtain the initial concentration change rates between several groups of adjacent inspection position points; respectively compare and analyze the initial concentration change rates between each group of adjacent inspection position points with the preset concentration threshold; if the initial concentration change rate between adjacent inspection position points is higher than the preset concentration threshold, it is regarded as an abnormal inspection position point.

[0010] Furthermore, the target gas wind direction concentration data includes the initial concentration values of the target gas in several directions. The specific steps to determine the predicted leakage direction of the target gas are as follows: For the abnormal inspection position points, obtain the environmental status data in several directions respectively, and perform calibration processing on the initial concentration values of the target gas in each direction to obtain the calibrated concentration values of the target gas in each direction at the abnormal inspection position points; Based on the calibrated concentration values of the target gas in each direction at the abnormal inspection position points, analyze the leakage direction scores in several directions at the abnormal inspection position points; Compare and analyze the leakage direction scores in several directions at the abnormal inspection position points, and regard the direction corresponding to the maximum leakage direction score at the abnormal inspection position point as the predicted leakage direction of the target gas.

[0011] Furthermore, the environmental status data includes the environmental temperature value, environmental humidity value, and environmental pressure value. The specific steps to obtain the calibrated concentration values of the target gas in each direction at the abnormal inspection position points are as follows: Obtain the environmental status calibration data at the abnormal inspection position points in each direction, and the environmental status calibration data includes the environmental temperature calibration value, environmental humidity calibration value, and environmental pressure calibration value; Combine the initial concentration values of the target gas in each direction at the abnormal inspection position points with the environmental status data and environmental status calibration data in the corresponding direction for comprehensive analysis to obtain the calibrated concentration values of the target gas in each direction at the abnormal inspection position points.

[0012] Furthermore, the specific steps to analyze the leakage direction scores in several directions at the abnormal inspection position points are as follows: Obtain the calibrated concentration reference value, direction distance value, direction angle value, and wind direction angle value of the target gas in each direction at the abnormal inspection position points; Combine the calibrated concentration values of the target gas in each direction at the abnormal inspection position points with the calibrated concentration reference value, direction distance value, direction angle value, and wind direction angle value in the corresponding direction for comprehensive analysis to obtain the leakage direction scores in each direction at the abnormal inspection position points.

[0013] Furthermore, the specific steps to calculate the leakage direction score of a certain direction at the abnormal inspection position point are as follows: ; where The leakage direction score of a certain direction at the abnormal inspection position point is the calibrated concentration value of the target gas in a certain direction at the abnormal inspection position point is the calibrated concentration reference value of the target gas in a certain direction at the abnormal inspection position point is the direction distance value of a certain direction at the abnormal inspection position point is the distance adjustment coefficient stored in the database is the direction angle value of a certain direction at the abnormal inspection position point is the wind direction angle value of a certain direction at the abnormal inspection position point It is the wind direction adjustment coefficient stored in the database.

[0014] Furthermore, the telemetry concentration distribution data includes the target gas concentration values and measurement two-dimensional coordinates of a number of measurement points at a number of time points, and the image data includes the pixel values and two-dimensional coordinates of a number of leakage pixel points of the gas leakage area images at a number of time points.

[0015] Furthermore, the specific steps to obtain the leakage point position information of the target gas are as follows: Read the telemetry concentration distribution data and image data at the predicted leakage direction of the target gas, and perform preprocessing respectively; Initialize the preset gas diffusion model and run the preset gas diffusion model; Combine the telemetry concentration distribution data and image data at the predicted leakage direction of the target gas with the operation result of the preset gas diffusion model for joint analysis, and determine the leakage point position information of the target gas.

[0016] The present invention has the following beneficial effects: (1) For the vehicle-mounted pan-tilt laser telemetry scanning type gas leakage positioning system, by introducing the signal saturation upper limit value and the fixed optical path length value for normalization processing, the nonlinear deviation caused by harmonic response saturation under high absorption or interference conditions is avoided. At the same time, during the inversion process, calibration is performed based on the gas absorption coefficient stored in the database, so that the calculated initial concentration value has good physical interpretability and dynamic adaptability. At the same time, the inversion process is independently completed at each inspection position point, and combined with the continuous sampling mechanism of vehicle movement, the dynamic continuous distribution reconstruction of the target gas concentration in the spatial dimension is realized. This mechanism has stronger scene adaptability compared with the traditional periodic or fixed-point sampling method, and is particularly suitable for high-precision leakage monitoring in complex scenarios such as urban gas pipelines and chemical industrial parks.

[0017] (2) For the vehicle-mounted pan-tilt laser telemetry scanning type gas leakage positioning system, the concentration analysis unit automatically calculates the concentration change rate between adjacent inspection position points, and combines the concentration threshold and the change rate threshold for double judgment to realize the real-time identification of abnormal inspection position points. This identification mechanism not only improves the system's sensitive capture ability at the initial stage of leakage occurrence, but also avoids the situation of being misjudged as normal due to the concentration level being lower than the single-point threshold. On this basis, the system further introduces a leakage direction analysis module to obtain the wind direction concentration data in multiple directions, and on the basis of correcting the environmental temperature, humidity, and air pressure, determines the maximum leakage score direction by constructing a multi-factor scoring model. This direction is the predicted leakage direction of the target gas. Compared with the traditional system that is difficult to provide the leakage direction, it can not only identify whether there is a leakage, but also greatly improve the early warning ability and disposal efficiency during the inspection process.

[0018] (3) After identifying the abnormal inspection position points and the leakage direction, the vehicle-mounted pan-tilt laser telemetry scanning type gas leakage positioning system further mobilizes the laser telemetry equipment to perform high-density scanning on the target direction through the leakage position analysis unit, obtaining concentration distribution data and image pixel data at multiple time points and multiple measurement positions. In particular, the designed image data contains the concentration mapping values and two-dimensional coordinate information of several pixel points within the leakage area, enabling the system to synchronously construct a concentration gradient field at the image level. By spatially aligning the concentration data with the gas cloud diffusion form in the image and jointly fitting and analyzing the operation results of the Gaussian diffusion model, the system can deduce the most likely leakage path and inversely infer the starting source point position of the gas leakage. Compared with the traditional rough positioning method that can only judge the leakage area, this method can accurately depict the spatial coordinates of the leakage source point, helping front-line repair personnel quickly arrive at the scene for disposal and comprehensively improving the gas safety control ability.

[0019] Of course, it is not necessary for any product implementing the present invention to simultaneously achieve all the above-mentioned advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a block diagram of a vehicle-mounted pan-tilt laser telemetry scanning type gas leakage positioning system according to the present invention.

[0021] Figure 2 It is a specific step flow chart for determining the predicted leakage direction of the target gas in a vehicle-mounted pan-tilt laser telemetry scanning type gas leakage positioning system according to the present invention.

[0022] Figure 3 It is a line graph of the corrected concentration values of the target gas in five directions at the abnormal inspection position point in a vehicle-mounted pan-tilt laser telemetry scanning type gas leakage positioning system according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] Please refer to Figure 1, an embodiment of the present invention provides a technical solution: a vehicle-mounted pan-tilt laser telemetry scanning type gas leakage positioning system, including: a data acquisition unit, integrated with a quantum cascade laser (QCL), the QCL operates in the 3345 nm mid-infrared band, and can simultaneously excite the absorption spectral lines of methane and ethane, and is used to obtain the laser absorption second harmonic signal intensity at a number of inspection position points on the set inspection route of the inspection vehicle; a concentration inversion processing unit, which is used to invert the initial concentration value of the target gas (methane and ethane gas) at each inspection position point based on the laser absorption second harmonic signal intensity; a concentration analysis unit, which is used to compare the concentration change rate of the target gas (methane and ethane gas) between adjacent inspection position points, and identify abnormal inspection position points based on a preset concentration threshold and change rate threshold, and when an abnormal inspection position point is identified, control the inspection vehicle to stop running; a leakage direction analysis unit, integrated with a near-infrared telemetry type methane and ethane identification device, the device operates in the 1680 nm near-infrared band, and can accurately extract the characteristic absorption spectral lines of ethane, and is used to obtain the wind direction concentration data of the target gas at the abnormal inspection position point and determine the predicted leakage direction of the target gas; a leakage position analysis unit, which is used to control the pan-tilt laser telemetry device on the inspection vehicle to perform telemetry scanning in the predicted leakage direction of the target gas, and obtain the telemetry concentration distribution data and image data at the predicted leakage direction of the target gas, and perform joint analysis in combination with a preset gas diffusion model to obtain the leakage point position information of the target gas (methane and ethane gas).

[0024] Specifically, the specific steps of inverting the initial concentration value of the target gas at each inspection position point based on the laser absorption second harmonic signal intensity are as follows: obtain the signal saturation upper limit value and the optical path length value; comprehensively analyze the laser absorption second harmonic signal intensity at each inspection position point in combination with the signal saturation upper limit value and the optical path length value respectively to obtain the initial concentration value of the target gas at each inspection position point.

[0025] Among them, the signal saturation upper limit value refers to the maximum stable signal voltage value that the lock-in amplifier in the system can output, which is used to limit the upper limit of the laser absorption harmonic signal, prevent nonlinear distortion or output saturation of the spectral response under high absorption or system interference, and is automatically calibrated during system initialization. Specifically, it includes: during the startup stage of the inspection vehicle, keep the laser at a fixed emission intensity and make the absorption cell in a pure background gas environment (such as no methane); control the lock-in amplifier to perform automatic adjustment of the maximum sensitivity, and record its maximum stable output value without signal interference as the system signal saturation upper limit value, and this value is stored in the internal cache of the device or the control chip for dynamic call during subsequent concentration inversion.

[0026] The optical path length value refers to the equivalent propagation distance formed by multiple reflections of the laser in the gas absorption unit, that is, the total length of the path that the laser actually contacts the measured gas. It is determined by the arrangement of the reflectors in the optical reflection cavity and the number of reflections. It is usually a fixed value. When the equipment is initially shipped, the manufacturer measures it according to the optical cavity design and solidifies it as a parameter configuration value. It will not change after installation, and the system software reads this value as the optical path length value.

[0027] The intensity of the second harmonic signal of laser absorption refers to the second harmonic component generated in the phase-locked detection system after the target gas absorbs the laser energy. Its amplitude is approximately linearly related to the concentration of the measured gas. It is the direct core signal used to extract the concentration in the laser modulation absorption spectroscopy (TDLAS) technology. It is obtained by the following steps: The laser is controlled to emit a laser beam of a specified wavelength at a preset modulation frequency into a multiple reflection gas cell, where energy is absorbed by gas molecules. The receiving end obtains the transmission signal through a photodetector, and extracts the second harmonic component (2f component) after processing by a lock-in amplifier. The system collects the amplitude of this component as the laser absorption second harmonic signal intensity corresponding to the inspection position, and records it in conjunction with time and space points for subsequent concentration inversion calculations.

[0028] The specific formula for calculating the initial concentration value of the target gas at each inspection location is as follows: ;in, is the initial concentration value of the target gas at a certain inspection location, is the intensity of the second harmonic signal absorbed by the laser at a certain inspection position. is the absorption coefficient stored in the database, is the optical path length, is the upper limit of signal saturation.

[0029] It should be explained that the absorption coefficients stored in the database The specific acquisition steps are as follows: During the factory calibration stage, under the condition of standard gas of known concentration, the intensity of the second harmonic signal of laser absorption is experimentally collected, and combined with the set optical path length, the absorption coefficient corresponding to the unit concentration is reversely calculated according to the Beer-Lambert law; the absorption coefficient is classified according to different wavelengths and target gas types and stored in the system database as the basic parameter called for concentration calculation during the inspection process.

[0030] In this implementation scheme, by constructing a complete target gas concentration inversion mechanism, the accuracy and robustness of concentration measurement during the inspection process are significantly improved. The system introduces a signal saturation upper limit value in the inversion process, which can effectively suppress the nonlinear distortion problem under high absorption or strong interference conditions, and ensure the stable output of harmonic signals within the dynamic range; at the same time, the introduction of a fixed optical path length value ensures the consistency of the spectral path at different inspection points, avoiding concentration measurement errors caused by structural changes. In addition, the system uses the intensity of the second harmonic signal of laser absorption as the core measurement indicator, and combines the output signal of the phase-locked amplifier to achieve high-sensitivity detection, and has strong resistance to background noise; the inversion process is standardized and corrected by the gas absorption coefficient stored in the database, ensuring that the concentration inversion under different gases and different wavelengths has good physical consistency and cross-scenario adaptability. The inversion mechanism supports independent calculation of each inspection position point, and combines vehicle movement to achieve high spatial resolution concentration reconstruction, providing a solid data foundation for subsequent leakage judgment and positioning, which is particularly suitable for high-precision detection of medium and low concentration target gases such as methane and ethane.

[0031] Specifically, the specific steps of comparing the concentration change rate of the target gas between adjacent inspection points and identifying abnormal inspection points based on a preset concentration threshold and a change rate threshold are as follows: read the initial concentration value of the target gas at each inspection point, and perform adjacent concentration change analysis to obtain the initial concentration change rate between several groups of adjacent inspection points; compare and analyze the initial concentration change rate between each group of adjacent inspection points with the preset concentration threshold; if the initial concentration change rate between adjacent inspection points is higher than the preset concentration threshold, it is regarded as an abnormal inspection point (that is, the second inspection point between adjacent inspection points is regarded as an abnormal inspection point).

[0032] In this implementation scheme, by calculating and judging the initial concentration change rate between adjacent inspection positions, dynamic identification of abnormal concentration changes is achieved, effectively improving the system's early warning capability for gas leaks. Compared with the traditional single-point judgment method based on absolute concentration values, by introducing concentration gradient analysis, it is possible to capture the leakage trend reflected by local concentration changes and avoid missed detection problems caused by low background concentrations. The system performs dual judgment based on preset concentration thresholds and change rate thresholds to ensure that the judgment logic is sensitive and stable, and can flexibly adjust parameters according to different scenarios, making the monitoring mechanism more intelligent and adaptive. By automatically marking points with concentration change rates higher than the threshold as abnormal inspection positions, the system can promptly trigger subsequent operations such as vehicle parking and direction analysis, thereby building an inspection decision chain with dynamic response capabilities.

[0033] Specifically, Figure 2As shown in the figure, the target gas wind direction concentration data includes the initial concentration values of the target gas in several directions. The specific steps to determine the predicted leakage direction of the target gas are as follows: For the abnormal inspection position points, obtain the environmental status data in several directions respectively, and perform calibration processing on the initial concentration values of the target gas in each direction to obtain the calibrated concentration values of the target gas in each direction at the abnormal inspection position points; Based on the calibrated concentration values of the target gas in each direction at the abnormal inspection position points, analyze the leakage direction scores in several directions at the abnormal inspection position points; Compare and analyze the leakage direction scores in several directions at the abnormal inspection position points, and regard the direction corresponding to the maximum leakage direction score at the abnormal inspection position point as the predicted leakage direction of the target gas.

[0034] In this implementation plan, the intelligent determination of the gas leakage direction at the abnormal inspection position points is realized, significantly enhancing the spatial perception ability and leakage response efficiency of the system. By obtaining the initial concentration of the target gas in multiple directions and combining the state data such as environmental temperature, humidity, and air pressure for calibration processing, it is ensured that the concentration data is comparable in multiple directions and multiple environments, eliminating the judgment errors caused by meteorological condition differences. The system further constructs a direction score model based on the calibrated concentration values, comprehensively analyzes the leakage trends in each direction, and finally selects the direction with the highest score as the predicted leakage direction, achieving a key breakthrough from concentration recognition to direction inference. Compared with the traditional leakage judgment method without direction perception, this mechanism significantly improves the accuracy of leakage source tracking and the response directivity, and is particularly suitable for urban inspection scenarios with complex multi-channels or significant wind field interference.

[0035] Specifically, the environmental status data includes the environmental temperature value, environmental humidity value, and environmental air pressure value. The specific steps to obtain the calibrated concentration values of the target gas in each direction at the abnormal inspection position points are as follows: Obtain the environmental status calibration data in each direction at the abnormal inspection position points, and the environmental status calibration data includes the environmental temperature calibration value, environmental humidity calibration value, and environmental air pressure calibration value; Combine the initial concentration values of the target gas in each direction at the abnormal inspection position points with the environmental status data and environmental status calibration data in the corresponding direction for comprehensive analysis to obtain the calibrated concentration values of the target gas in each direction at the abnormal inspection position points.

[0036] Among them, the environmental temperature calibration value is obtained by measuring the concentration of the target gas using a gas detection device (such as a laser absorption spectrometer) under different temperature conditions in the experiment and recording the corresponding temperature values. By comparing the standard concentration with the actual measured concentration, analyzing the influence of temperature on gas concentration measurement, and using regression analysis to calculate the correction coefficient of environmental temperature on concentration, the environmental temperature calibration value in each direction is obtained.

[0037] The environmental humidity reference value is obtained through experiments under different humidity conditions. A gas detection device is used to measure the concentration of the target gas, and the corresponding humidity values are recorded. By comparing the differences between the gas concentrations under different humidity conditions and the standard concentration, the influence of humidity on concentration measurement is analyzed. Finally, through regression analysis, humidity correction coefficients are obtained, and these coefficients are used to correct the actual measured concentration to obtain the humidity reference value.

[0038] The environmental air pressure reference value is obtained in the experiment by measuring the gas concentration under different air pressure conditions, recording the gas concentration and the corresponding air pressure value under each air pressure condition, analyzing the influence of air pressure on concentration measurement by comparing with the standard concentration, obtaining the correction coefficient of air pressure using regression analysis, and finally obtaining the environmental air pressure reference value in each direction. These reference values can help accurately correct the gas concentration in different air pressure environments.

[0039] The specific formula for calculating the corrected concentration value of the target gas in a certain direction at the abnormal inspection position point is as follows: ; where is the corrected concentration value of the target gas in a certain direction at the abnormal inspection position point, is the initial concentration value of the target gas in a certain direction at the abnormal inspection position point, is the environmental temperature value in a certain direction at the abnormal inspection position point, is the environmental temperature reference value in a certain direction at the abnormal inspection position point, is the temperature correction coefficient stored in the database, is the environmental humidity value in a certain direction at the abnormal inspection position point, is the environmental humidity reference value in a certain direction at the abnormal inspection position point, is the humidity correction coefficient stored in the database, is the environmental air pressure value in a certain direction at the abnormal inspection position point, is the environmental air pressure reference value in a certain direction at the abnormal inspection position point, is the air pressure correction coefficient stored in the database.

[0040] It should be explained that the specific acquisition steps of the temperature correction coefficient , humidity correction coefficient , and air pressure correction coefficient stored in the database are as follows: First, different temperature, humidity, and air pressure conditions are selected in the experiment, the concentration of the target gas in the direction is measured, and the environmental temperature, humidity, and air pressure values are recorded. Then, based on these data, the differences between the actual measured values of the gas concentration under different environmental conditions and the standard concentration are compared, the correction effects of temperature, humidity, and air pressure on the concentration are calculated, and through regression analysis and fitting, the coefficients 、 , , finally, these correction factors are stored in the database, and during the actual monitoring process, according to the current temperature, humidity, and air pressure conditions, the corresponding correction factors are applied to adjust the gas concentration measurement values to ensure the accuracy of the concentration data in different environments.

[0041] Among them, a specific implementation example of calculating the target gas corrected concentration value in a certain direction at the abnormal inspection position point is as follows. The target gas is ethane gas, and the following parameters are available: The initial concentration value of the target gas in a certain direction at the abnormal inspection position point is approximately: 81.327 ppm.

[0042] The environmental temperature value in a certain direction at the abnormal inspection position point is approximately: 27.384 °C.

[0043] The reference environmental temperature value in a certain direction at the abnormal inspection position point is approximately: 25.000 °C.

[0044] The temperature correction factor stored in the database is approximately: 0.0023.

[0045] The environmental humidity value in a certain direction at the abnormal inspection position point is approximately: 63.912% RH.

[0046] The reference environmental humidity value in a certain direction at the abnormal inspection position point is approximately: 60.000% RH.

[0047] The humidity correction factor stored in the database is approximately: 0.0018.

[0048] The environmental air pressure value in a certain direction at the abnormal inspection position point is approximately: 1014.102 hPa.

[0049] The reference environmental air pressure value in a certain direction at the abnormal inspection position point is approximately: 1013.000 hPa.

[0050] The air pressure correction factor stored in the database is approximately: 0.0015.

[0051] Substitute the above data into the specific formula for calculating the target gas corrected concentration value in a certain direction at the abnormal inspection position point, and we get: The target gas corrected concentration value in a certain direction at the abnormal inspection position point = 81.327 × ((((27.384 - 25.000) / 25.000) ^ 0.0023) × ((((63.912 - 60.000) / 60.000) ^ 0.0018) × ((((1014.102 - 1013.000) / 1013.000) ^ 0.0015)))) ≈ 79.672 ppm.

[0052] Specific implementation examples of the corrected concentration values of the target gas in several directions at the abnormal inspection position are as follows. The existing data includes the corrected concentration values of the target gas in five directions (due north, due east, due south, due west, and northeast). The specific data is shown in Table 1 and Figure 3 as follows: Table 1 Example data of the corrected concentration values of the target gas in five directions at the abnormal inspection position

[0053] In this implementation plan, by introducing a multi-dimensional correction mechanism for environmental temperature, humidity, and air pressure, the accurate correction of the initial concentration value of the target gas is achieved, ensuring the high consistency and physical credibility of the concentration data in different directions and environmental conditions. Compared with the traditional measurement method that ignores environmental interference factors, this plan first constructs a dataset for determining environmental state parameters, and combines the actual measured values of temperature, humidity, and air pressure with the correction coefficients stored in the database for exponential deviation correction, effectively eliminating the distortion of the external environment on the gas concentration detection results. Through this correction method, the concentration data in each direction can be compared under unified standard conditions, improving the spatial comparability and stability of the data. Especially in the inspection scenarios with frequent wind field disturbances and large micro-environment differences, it has significant advantages. In addition, the system supports real-time calculation with example data and outputs the corrected concentration trends in different directions, presented visually in combination with charts, realizing a smooth transition from data correction to direction discrimination, providing a reliable input basis for subsequent leakage direction scoring and source tracing positioning. This mechanism is particularly crucial in the high-precision monitoring of easily diffusible gases such as ethane, ensuring the accuracy and reliability of leakage identification.

[0054] Specifically, the specific steps for analyzing the leakage direction scores in several directions at the abnormal inspection position are as follows: Obtain the corrected concentration reference values, direction distance values, direction angle values, and wind direction angle values of the target gas in each direction at the abnormal inspection position; comprehensively analyze the corrected concentration values of the target gas in each direction at the abnormal inspection position by combining the corrected concentration reference values, direction distance values, direction angle values, and wind direction angle values in the corresponding directions, respectively, to obtain the leakage direction scores in each direction at the abnormal inspection position.

[0055] Among them, the corrected concentration reference value of the target gas refers to the gas concentration value under a known standard concentration under specific environmental conditions, which is used to correct the concentration measurement error caused by environmental changes. The steps for obtaining it include: First, under different temperature, humidity, and air pressure conditions, use a gas detection device (such as a laser absorption spectrometer) to measure the concentration of the target gas and record the concentration value under each condition. Then, by comparing the standard concentration with the actual measured concentration, analyze the influence of environmental factors on the concentration measurement, and finally obtain the corresponding corrected concentration reference value of the target gas.

[0056] The direction distance value represents the actual spatial distance between the abnormal inspection position point and the measurement points in each direction. The steps to obtain it include: First, the precise coordinates of the abnormal inspection position point need to be determined. Then, according to the inspection path planning, the measurement points in each direction (such as due north, due east, etc.) are determined. Finally, the distance between the inspection position and the measurement points is calculated, usually obtained through the Euclidean distance formula in three-dimensional space. This distance value reflects the spatial relationship between the measurement points in each direction and the abnormal inspection position point and is stored in the database for subsequent direction analysis and leakage direction scoring.

[0057] The direction angle value represents the relative azimuth angle from the abnormal inspection position point to the target gas leakage point and is used to describe the possible direction of gas leakage. The steps to obtain it include: First, the coordinates of the abnormal inspection position point and the position of the target gas leakage source need to be determined. Through the azimuth sensor or angle measurement instrument of the inspection device, the azimuth angle between the target gas leakage point and each measurement point is calculated. This angle value represents the relative direction between each direction and the leakage source, is stored in the database, and is used for subsequent leakage direction analysis and scoring to ensure the positioning accuracy of the leakage source.

[0058] The wind direction angle value is used to describe the blowing direction of the current wind. The direction of the wind has an important impact on gas diffusion and concentration distribution. The steps to obtain it include: Using a wind speed and direction instrument to monitor and record the wind direction in real time. The wind direction angle value is usually expressed in degrees, with 0° representing due north and 90° representing due east, etc. Through the measurement data of the wind speed and direction instrument, the current wind direction angle is obtained. After necessary correction, this value is stored in the database. In gas leakage monitoring, the wind direction angle value will be an important correction parameter affecting the direction and concentration distribution of gas diffusion.

[0059] The specific steps to calculate the leakage direction score in a certain direction at the abnormal inspection position point are as follows: ; where The leakage direction score in a certain direction at the abnormal inspection position point, is the target gas corrected concentration value in a certain direction at the abnormal inspection position point, is the target gas corrected concentration reference value in a certain direction at the abnormal inspection position point, is the direction distance value in a certain direction at the abnormal inspection position point, is the distance adjustment coefficient stored in the database, is the direction angle value in a certain direction at the abnormal inspection position point, is the wind direction angle value in a certain direction at the abnormal inspection position point, is the wind direction adjustment coefficient stored in the database.

[0060] It should be explained that the distance adjustment coefficient stored in the database 、Wind direction adjustment coefficient The specific steps for obtaining it are as follows: First, select multiple different measurement distances and wind direction conditions, record the changes in the target gas concentration under each condition, and then perform regression analysis and fitting based on the experimental data to obtain the corresponding distance adjustment coefficient and wind direction adjustment coefficient.

[0061] In this implementation plan, by introducing multi-dimensional factors to construct a leakage direction scoring model, the scientific evaluation and accurate determination of the potential leakage direction at the abnormal patrol location points are realized, significantly improving the leakage direction recognition ability of the system in complex environments. The system comprehensively considers the target gas corrected concentration value in each direction, the deviation degree from the standard reference value, the direction distance value, the direction angle value and the current wind direction angle value, and introduces the distance adjustment coefficient and wind direction adjustment coefficient obtained by regression fitting of the measured data, making the scoring result closer to the actual gas diffusion law. Compared with the method that only relies on the absolute value of the concentration for judgment, this method effectively avoids misjudgment or direction distortion caused by factors such as local wind disturbance and terrain shielding. The direction distance value can quantify the spatial attenuation of the leakage source possibility, and the coupled analysis of the direction angle value and the wind direction angle value clarifies the main propagation path of the gas. The scoring formula structure is flexible and can be extended to the comprehensive analysis of multi-directions and multi-branch paths, showing significant adaptability to complex wind fields or uneven target diffusion scenarios. Finally, the system infers the main leakage direction based on the maximum score, which not only enhances the system's perception ability of the leakage trend but also provides clear guidance for subsequent telemetry scanning and point locking.

[0062] Specifically, the telemetry concentration distribution data includes the target gas concentration values and measurement two-dimensional coordinates of several measurement points at several time points, and the image data includes the pixel values and two-dimensional coordinates of several leakage pixel points of the gas leakage area images at several time points.

[0063] The specific steps to obtain the leakage point location information of the target gas are as follows: Read the telemetry concentration distribution data and image data at the predicted leakage direction of the target gas and perform preprocessing respectively; Initialize the preset gas diffusion model (Gaussian diffusion model in this embodiment) and run the preset gas diffusion model; Combine the telemetry concentration distribution data and image data at the predicted leakage direction of the target gas with the operation result of the preset gas diffusion model for joint analysis and determine the leakage point location information of the target gas. The specific example steps are as follows: The pan-tilt QCL laser detection device (wavelength: 3345nm) and the near-infrared ethane special module (1680nm) carried by the patrol vehicle perform telemetry scanning on the target area and collect data of multiple measurement points at several time points. The data content includes: The two-dimensional coordinates of each measurement point (such as GPS projection coordinates); The methane concentration value (unit: ppm) at a certain position point at a certain moment; The ethane concentration value (unit: ppm) at the same moment; Simultaneously collect infrared images or optically enhanced images of the gas leakage area to form a gas cloud map. Each frame of the image contains: The pixel gray values of several leakage area pixel points (representing absorption intensity or thermal anomaly); The two-dimensional image coordinates of each pixel; Align the pixel timestamp with the corresponding concentration data in time; Environmental parameter correction; Perform three correction processes on the original concentration value: Use the environmental temperature, humidity, and air pressure reference values + the current environmental parameters, and call the correction coefficients stored in the database for concentration calibration; Example: The original methane concentration value is 81.327 ppm, and it becomes 79.672 ppm after being corrected by the three factors of temperature, humidity, and air pressure; Perform a similar correction on the ethane concentration at the same time; Preprocess the image data, including: Image denoising: Use Gaussian filtering to remove background disturbances; Contrast enhancement: Enhance the gray-scale change at the cloud edge to extract the concentration boundary; Pixel value mapping: Construct a pseudo-color concentration map based on the pixel value-concentration mapping relationship; Coordinate alignment: Use the camera calibration matrix or spatial mapping relationship to map the two-dimensional image coordinates to the actual GPS plane coordinates to ensure the spatial coincidence of the image pixels and the concentration measurement points; Leakage gas types: methane, ethane (with different molecular masses and specific gravities); Selected leakage type: continuous small-flow leakage; Wind speed setting: such as 1.8 m / s; wind direction is set to 15° east of true north; The horizontal diffusion coefficient and the vertical diffusion coefficient are set according to the Pasquill stability category; Initial concentration: Use the maximum concentration value in the telemetry data or 90% of it as the initial concentration; Run the simulation and output the predicted concentration distribution (spatial grid matrix) at each time step; Calculate the gas concentration isocontours, centerline trajectories, and main diffusion paths at each simulation time point; Comparison between the concentration map and the simulation: Match the telemetry concentration distribution with the output of the Gaussian model at the points; Compare the overlap degree of the actual and simulated concentration fields at each time point, and use indicators such as cosine similarity and mean square error to evaluate the degree of coincidence; If the difference is large, adjust the model parameters (wind speed, diffusion coefficient); Comparison between image data and the model: Compare the shape of the gas cloud in the image with the diffusion contour lines in the Gaussian model; Combined with pixel concentration mapping data, analyze whether the image concentration distribution is consistent with the simulation; Use the cloud expansion speed and direction deduced from the image to assist in verifying the rationality of the wind direction setting; Inverse positioning of the leakage point: Find the measurement point with the most drastic change in concentration in the telemetry concentration data; Determine the reverse direction of the concentration gradient, that is, the countercurrent direction of the suspected leakage source; Triangulation method: Select three high-concentration measurement points, intersect with the concentration gradient direction as the vector, and calculate the intersection coordinates as the initial estimate of the leakage point; Image-assisted verification: Confirm whether this point in the concentration map is located in the gas cloud source area; Database record: Write all the two-dimensional coordinates of the final leakage point, concentration time series, wind direction data, model parameters, and image frame numbers into the database; For forming a leakage event file and future retrospective analysis; Report output: Include the leakage point coordinates (WGS84 / Gauss plane coordinates), gas type (methane or ethane), and maximum concentration value.

[0064] In this implementation plan, this part of the content realizes the high-precision positioning of the leakage point location information by constructing a complete fusion analysis mechanism of telemetry concentration distribution data and image data, combined with environmental correction and gas diffusion model simulation, and has significant practical and innovative advantages. On the one hand, this method simultaneously telemeters methane and ethane based on laser absorption spectroscopy, fuses the leakage cloud shape information extracted from infrared images or optical images, and establishes a synchronous alignment mechanism at the time and space levels to ensure the high consistency between the image pixel concentration value and the actual telemetry point concentration value; on the other hand, by introducing the physical correction formula of three factors of temperature, humidity, and air pressure, the influence of external environmental disturbances on the measurement accuracy is eliminated, effectively improving the accuracy of concentration inversion. During the process of determining the leakage location, a Gaussian diffusion model is used for simulation. Through the multi-dimensional matching of the model with the actual concentration field and the image air mass shape, the accuracy of leakage path judgment and leakage source inversion is greatly improved. Finally, the triangulation method is used to output the precise spatial coordinates of the leakage point, providing verifiable and traceable technical support for the fixed-point traceability and response intervention of industrial gas leakage.

[0065] Although the preferred embodiments of the present invention have been described, additional changes and modifications can be made to these embodiments by those skilled in the art once they learn of the basic inventive concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present invention.

[0066] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A vehicle-mounted pan-tilt laser telemetry scanning gas leak location system, characterized in that: include: A data acquisition unit, used to acquire the intensity of the laser absorption second harmonic signal at a plurality of inspection positions of the inspection vehicle on a set inspection route; A concentration inversion processing unit, used to invert the initial concentration value of the target gas at each inspection position point based on the intensity of the laser absorption second harmonic signal; A concentration analysis unit, used to compare the concentration change rate of the target gas between adjacent inspection positions, and identify abnormal inspection positions based on a preset concentration threshold and change rate threshold; A leakage direction analysis unit is used to obtain the target gas wind direction concentration data at the abnormal inspection location point and determine the predicted leakage direction of the target gas; The leakage location analysis unit is used to obtain the remote sensing concentration distribution data and image data at the predicted leakage direction of the target gas, and perform joint analysis in combination with a preset gas diffusion model to obtain the leakage point location information of the target gas.

2. The vehicle-mounted pan-tilt laser telemetry scanning gas leak location system according to claim 1 is characterized in that: Based on the intensity of the laser absorption second harmonic signal, the specific steps for inverting the initial concentration value of the target gas at each inspection location are as follows: Obtain the signal saturation upper limit value and the optical path length value; The intensity of the laser absorption second harmonic signal at each inspection position is combined with the signal saturation upper limit value and the optical path length value for comprehensive analysis to obtain the initial concentration value of the target gas at each inspection position.

3. The vehicle-mounted pan-tilt laser telemetry scanning gas leak location system according to claim 1 is characterized in that: The specific formula for calculating the initial concentration value of the target gas at each inspection location is as follows: ； in, is the initial concentration value of the target gas at a certain inspection location, is the intensity of the second harmonic signal absorbed by the laser at a certain inspection position. is the absorption coefficient stored in the database, is the optical path length, is the upper limit of signal saturation.

4. The vehicle-mounted pan-tilt laser telemetry scanning gas leak locating system according to claim 1 is characterized in that: The specific steps of comparing the concentration change rates of the target gas between adjacent inspection positions and identifying abnormal inspection positions based on the preset concentration threshold and change rate threshold are as follows: Read the initial concentration value of the target gas at each inspection position, and perform adjacent concentration change analysis to obtain the initial concentration change rate between several groups of adjacent inspection positions; The initial concentration change rate between each group of adjacent inspection position points is compared and analyzed with the preset concentration threshold value; If the initial concentration change rate between adjacent inspection positions is higher than the preset concentration threshold, it is regarded as an abnormal inspection position.

5. The vehicle-mounted pan-tilt laser telemetry scanning gas leak location system according to claim 1 is characterized in that: The target gas wind direction concentration data includes the target gas initial concentration values ​​in several directions. The specific steps for determining the predicted leakage direction of the target gas are as follows: For the abnormal inspection location point, the environmental status data in several directions are obtained respectively, and the initial concentration value of the target gas in each direction is corrected to obtain the corrected concentration value of the target gas in each direction at the abnormal inspection location point; Based on the target gas correction concentration value in each direction at the abnormal inspection location point, the leakage direction scores in several directions at the abnormal inspection location point are analyzed; The leakage direction scores of several directions at the abnormal inspection location are compared and analyzed, and the direction corresponding to the maximum leakage direction score at the abnormal inspection location is regarded as the predicted leakage direction of the target gas.

6. The vehicle-mounted pan-tilt laser telemetry scanning gas leak location system according to claim 5 is characterized in that: The environmental status data includes the environmental temperature value, the environmental humidity value, and the environmental pressure value. The specific steps for obtaining the target gas correction concentration value in each direction at the abnormal inspection location point are as follows: Obtaining environmental state parameter data in each direction at the abnormal inspection location point, wherein the environmental state parameter data includes an environmental temperature parameter value, an environmental humidity parameter value, and an environmental pressure parameter value; The initial concentration value of the target gas in each direction at the abnormal inspection location point is comprehensively analyzed in combination with the environmental state data and environmental state parameter data of the corresponding direction to obtain the corrected concentration value of the target gas in each direction at the abnormal inspection location point.

7. The vehicle-mounted pan-tilt laser telemetry scanning gas leak location system according to claim 1 is characterized in that: The specific steps for analyzing the leakage direction scores in several directions at the abnormal inspection location point are as follows: Obtain the target gas correction concentration parameter value, direction distance value, direction angle value, and wind direction angle value in each direction at the abnormal inspection location point; The target gas correction concentration value in each direction at the abnormal inspection location point is comprehensively analyzed in combination with the target gas correction concentration parameter value, direction distance value, direction angle value, and wind direction angle value of the corresponding direction to obtain the leakage direction score in each direction at the abnormal inspection location point.

8. The vehicle-mounted pan-tilt laser telemetry scanning gas leak locating system according to claim 1 is characterized in that: The specific steps for calculating the leakage direction score in a certain direction at the abnormal inspection location are as follows: ； in, , , , , , They are respectively the leakage direction score of a certain direction at the abnormal inspection position point, the target gas correction concentration value, the target gas correction concentration parameter value, the direction distance value, the direction angle value, and the wind direction angle value. , They are the distance adjustment coefficient and the wind direction adjustment coefficient stored in the database respectively.

9. The vehicle-mounted pan-tilt laser telemetry scanning gas leak location system according to claim 1 is characterized in that: The remote sensing concentration distribution data includes target gas concentration values ​​and two-dimensional coordinates of several measurement points at several time points, and the image data includes pixel values ​​and two-dimensional coordinates of several leakage pixel points of the gas leakage area image at several time points.

10. The vehicle-mounted pan-tilt laser telemetry scanning gas leak location system according to claim 1, characterized in that: The specific steps to obtain the target gas leakage point location information are as follows: Read the remote sensing concentration distribution data and image data at the predicted leakage direction of the target gas, and perform preprocessing respectively; Initializing a preset gas diffusion model and running the preset gas diffusion model; The remote sensing concentration distribution data and image data at the predicted leakage direction of the target gas are combined with the operation results of the preset gas diffusion model for joint analysis to determine the leakage point location information of the target gas.

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