A vehicle-mounted pan-tilt laser telemetry scanning gas leakage positioning system

Abstract

The present invention discloses a vehicle-mounted pan-tilt laser telemetry scanning gas leak location system, relating to the technical field of gas leak monitoring. The vehicle-mounted pan-tilt laser telemetry scanning gas leak location system includes a data acquisition unit that acquires the intensity of the laser absorption second harmonic signal of the inspection vehicle along a set route; a concentration inversion processing unit that inverts the gas concentration based on this signal; a concentration analysis unit that identifies abnormal inspection points by comparing the concentration change rate; a leakage direction analysis unit that predicts the leakage direction by combining wind direction concentration data; and a leakage location analysis unit that accurately locates the leakage point by combining remotely measured concentration distribution data and image data with a gas diffusion model. The present invention introduces a signal saturation upper limit value and an optical path length value for normalization processing, and combines the gas absorption coefficient for concentration inversion calibration. Independent calculations are performed at each inspection location, achieving spatially continuous, dynamic, and high-precision reconstruction of the concentration distribution.

Description

Technical Field

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

[0002] With the continuous advancement of urbanization, the risk of gas leakage is increasing. Especially in 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 to ensure public safety. At present, 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 great influence of environmental factors, making it difficult to cope with complex and changing monitoring environments.

[0003] Laser Absorption Spectroscopy (LAS), an advanced technology for accurately measuring gas concentration, is gradually being applied to gas leak monitoring due to its high sensitivity, high selectivity, and non-contact measurement. By analyzing the absorption signal after the interaction between the laser beam and gas molecules, this technology can accurately detect changes in gas concentration in real time with high spatial and temporal resolution. Although laser absorption spectroscopy has great advantages in gas detection, its application in vehicle-mounted gas leak monitoring systems still faces some challenges.

[0004] The limitations of existing technologies include at least the following: Traditional systems often rely on gas concentration threshold alarm mechanisms during inspections. Upon detecting an elevated concentration, they can only generally identify a leak, but are unable to further infer the specific spatial location of the leak source. This method of identifying concentration anomalies lacks directional judgment and concentration gradient analysis mechanisms, resulting in significant ambiguity in positioning results. These results can only be used to trigger alarms, making it difficult to guide precise disposal. Furthermore, existing systems fail to effectively incorporate gas diffusion models for inversion calculations, making it difficult to couple concentration data from different measurement points with environmental variables such as wind speed, wind direction, temperature, and humidity. Consequently, it is difficult to establish a logical chain for inferring the location of the leak source from the concentration distribution. Furthermore, in terms of data structure, most traditional systems collect single-point data, neglecting the recording of spatial coordinates and time dimensions. This makes it difficult to model the diffusion characteristics of concentration as it evolves over time and position, further limiting the accuracy of source location. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the present invention provides a vehicle-mounted pan-tilt laser telemetry scanning gas leak locating system, which solves the problem in the existing technology that it is difficult to accurately locate the leakage point.

[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 leak positioning system, comprising: a data acquisition unit, used to obtain the laser absorption second harmonic signal intensity of a patrol vehicle at several patrol positions on a set patrol route; a concentration inversion processing unit, used to invert the initial concentration value of the target gas at each patrol position based on the laser absorption second harmonic signal intensity; a concentration analysis unit, used to compare the concentration change rate of the target gas between adjacent patrol positions, and identify abnormal patrol positions based on a preset concentration threshold and a change rate threshold; a leakage direction analysis unit, used to obtain the target gas wind direction concentration data at the abnormal patrol position, and determine the predicted leakage direction of the target gas; a leakage position analysis unit, used to obtain the telemetry concentration distribution data and image data at the predicted leakage direction of the target gas, and perform a joint analysis in combination with a preset gas diffusion model to obtain the leakage point location information of the target gas.

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

[0008] Furthermore, 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 location, is the absorption coefficient stored in the database, is the optical path length, is the upper limit of signal saturation.

[0009] Furthermore, the specific steps of comparing the concentration change rate of the target gas between adjacent inspection points and identifying abnormal inspection points based on the preset concentration threshold and change rate threshold are as follows: reading the initial concentration value of the target gas at each inspection point, and performing adjacent concentration change analysis to obtain the initial concentration change rate between several groups of adjacent inspection points; comparing and analyzing 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.

[0010] Furthermore, the target gas wind direction concentration data includes the initial concentration values of the target gas in several directions, and the specific steps for determining the predicted leakage direction of the target gas are as follows: for the abnormal inspection location point, respectively obtain the environmental status data of several directions, and correct the initial concentration value of the target gas in each direction to obtain the corrected target gas concentration value in each direction at the abnormal inspection location point; based on the corrected target gas concentration value in each direction at the abnormal inspection location point, analyze the leakage direction scores of several directions at the abnormal inspection location point; compare and analyze the leakage direction scores of several directions at the abnormal inspection location point, and regard the direction corresponding to the maximum leakage direction score at the abnormal inspection location point as the predicted leakage direction of the target gas.

[0011] Furthermore, the environmental status data includes environmental temperature values, environmental humidity values, and environmental pressure values. The specific steps for obtaining the target gas correction concentration value in each direction at the abnormal inspection location point are as follows: obtaining the environmental status parameter data in each direction at the abnormal inspection location point, the environmental status parameter data including the environmental temperature parameter value, the environmental humidity parameter value, and the environmental pressure parameter value; comprehensively analyzing the initial target gas concentration value in each direction at the abnormal inspection location point in combination with the environmental status data and environmental status parameter data of the corresponding direction to obtain the target gas correction concentration value in each direction at the abnormal inspection location point.

[0012] Furthermore, the specific steps for analyzing the leakage direction scores of several directions at the abnormal inspection location points are as follows: obtain the target gas correction concentration parameter value, direction distance value, direction angle value, and wind direction angle value for each direction at the abnormal inspection location point; comprehensively analyze the target gas correction concentration value for each direction at the abnormal inspection location point 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 for each direction at the abnormal inspection location point.

[0013] Furthermore, the specific steps for calculating the leakage direction score of a certain direction at the abnormal inspection location point are as follows: ;in, Leakage direction score of a certain direction at the abnormal inspection location point, Correct the concentration value of the target gas in a certain direction at the abnormal inspection location. Correction concentration parameter value of target gas in a certain direction at abnormal inspection location. is the directional distance value in a certain direction at the abnormal inspection location point, is the distance adjustment coefficient stored in the database, is the direction angle value of a certain direction at the abnormal inspection location point, is the wind direction angle value in a certain direction at the abnormal inspection location point, It is the wind direction adjustment coefficient stored in the database.

[0014] Furthermore, the telemetry 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 in the gas leakage area image at several time points.

[0015] Furthermore, the specific steps for obtaining the target gas leakage point location information are as follows: reading the telemetry concentration distribution data and image data at the target gas predicted leakage direction, and preprocessing them respectively; initializing the preset gas diffusion model, and running the preset gas diffusion model; combining the telemetry concentration distribution data and image data at the target gas predicted leakage direction with the running results of the preset gas diffusion model for joint analysis, and determining the target gas leakage point location information.

[0016] The present invention has the following beneficial effects:

[0017] (1) The vehicle-mounted pan-tilt laser telemetry scanning gas leak location system avoids the nonlinear deviation caused by the saturation of the harmonic response under high absorption or interference conditions by introducing the signal saturation upper limit value and the fixed optical path length value for normalization processing. At the same time, the inversion process is calibrated 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 processing is completed independently at each inspection location point. Combined with the continuous sampling mechanism of vehicle movement, the target gas concentration is dynamically and continuously reconstructed in the spatial dimension. Compared with the traditional periodic or fixed-point sampling method, this mechanism has stronger scene adaptability and is particularly suitable for high-precision leakage monitoring in complex scenes such as urban gas pipelines and chemical parks.

[0018] (2) The vehicle-mounted pan-tilt laser telemetry scanning gas leak location system automatically calculates the concentration change rate between adjacent inspection points through the concentration analysis unit, and performs dual judgment based on the concentration threshold and the change rate threshold, thereby realizing real-time identification of abnormal inspection points. This identification mechanism not only improves the system's ability to sensitively capture the initial stage of a leak, but also avoids the situation where the concentration level is lower than the single-point threshold and is misjudged as normal. On this basis, the system further introduces a leakage direction analysis module to obtain wind direction concentration data in multiple directions, and on the basis of corrections to ambient 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 leakage direction, it can not only identify whether there is a leak, but also greatly improve the early warning capability and disposal efficiency of the inspection process.

[0019] (3) After identifying the abnormal inspection location and leakage direction, the vehicle-mounted pan-tilt laser telemetry scanning gas leak positioning system further mobilizes the laser telemetry equipment through the leakage location analysis unit to perform high-density scanning on the target direction, and obtains the concentration distribution data and image pixel data at multiple time points and multiple measurement locations. In particular, the designed image data contains the concentration mapping values and two-dimensional coordinate information of several pixel points in the leakage area, so that the system can simultaneously construct the concentration gradient field at the image level. By spatially aligning the concentration data with the gas cloud diffusion form in the image and linking the Gaussian diffusion model operation results for joint fitting analysis, the system can deduce the most likely leakage path and reversely infer the starting source position of the gas leak. Compared with the traditional rough positioning method that can only determine the leakage area, this method enables the spatial coordinates of the leakage source point to be accurately characterized, which helps the front-line emergency repair personnel to quickly arrive at the location to carry out disposal and comprehensively improve the gas safety management and control capabilities.

[0020] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a block diagram of a vehicle-mounted pan-tilt laser telemetry scanning gas leak locating system of the present invention.

[0022] Figure 2 This is a flowchart of the specific steps for determining the predicted leakage direction of the target gas in a vehicle-mounted pan-tilt laser telemetry scanning gas leak locating system of the present invention.

[0023] Figure 3 This is a line graph of target gas correction concentration value data in five directions at abnormal inspection locations in a vehicle-mounted pan-tilt laser telemetry scanning gas leak locating system of the present invention. DETAILED DESCRIPTION

[0024] See also Figure 1The embodiment of the present invention provides a technical solution: a vehicle-mounted pan-tilt laser telemetry scanning gas leak positioning system, comprising: a data acquisition unit, an integrated quantum cascade laser (QCL), the QCL operates in the 3345nm mid-infrared band, and can simultaneously excite the absorption lines of methane and ethane, and is used to obtain the laser absorption second harmonic signal intensity of the patrol vehicle at several patrol positions on the set patrol route; a concentration inversion processing unit, used to invert the initial concentration value of the target gas (methane and ethane gas) at each patrol position based on the laser absorption second harmonic signal intensity; a concentration analysis unit, used to compare the concentration change rate of the target gas (methane and ethane gas) between adjacent patrol positions, and identify the gas leak based on a preset concentration threshold and a change rate threshold. The system can identify abnormal inspection positions and control the inspection vehicle to stop running when an abnormal inspection position is identified; the leakage direction analysis unit integrates a near-infrared telemetry type ethane and ethane identification device, which works in the 1680nm near-infrared band and can accurately extract the characteristic absorption spectrum of ethane to obtain the target gas wind direction concentration data at the abnormal inspection position and determine the predicted leakage direction of the target gas; the leakage position analysis unit is used to control the pan-tilt laser telemetry equipment 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 the preset gas diffusion model to obtain the leakage point location information of the target gas (ethane and ethane gas).

[0025] Specifically, based on the intensity of the second harmonic signal of laser absorption, the specific steps for inverting the initial concentration value of the target gas at each inspection position are as follows: obtain the signal saturation upper limit value and the optical path length value; comprehensively analyze the intensity of the second harmonic signal of laser absorption at each inspection position in combination with the signal saturation upper limit value and the optical path length value to obtain the initial concentration value of the target gas at each inspection position.

[0026] Among them, the signal saturation upper limit refers to the maximum stable signal voltage value that can be output by the phase-locked amplifier in the system. It is used to limit the upper limit of the laser absorption harmonic signal to prevent nonlinear distortion or output saturation of the spectral response under high absorption or system interference. It is obtained by automatic calibration during system initialization, specifically including: during the startup phase of the inspection vehicle, the laser maintains a fixed emission intensity and the absorption gas cell is in a pure background gas environment (such as no methane); the phase-locked amplifier is controlled to automatically adjust the maximum sensitivity, and its maximum stable output value in the absence of signal interference is recorded as the system signal saturation upper limit. This value is stored in the internal cache of the device or in the control chip for dynamic call in subsequent concentration inversion.

[0027] The optical path length value refers to the equivalent propagation distance formed by multiple reflections of the laser in the gas absorption cell, that is, the total length of the path actually in contact with the measured gas. It is determined by the mirror arrangement and the number of reflections in the optical reflection cavity. It is usually a fixed value. When the equipment is initially shipped, the manufacturer measures it based on the optical cavity design and solidifies it as a parameter configuration value. It does not change after installation and is read by the system software as the optical path length value.

[0028] The laser absorption second harmonic signal intensity refers to the second harmonic component generated in the phase-locked detection system after the target gas absorbs laser energy. Its amplitude is approximately linearly related to the concentration of the measured gas. It is the direct core signal used to extract concentration in laser modulation absorption spectroscopy (TDLAS) technology. It is obtained through the following steps:

[0029] The laser is controlled to emit a laser beam of a specified wavelength at a preset modulation frequency into the multiple reflection gas cell, where it absorbs energy from the gas molecules. The receiving end obtains the transmitted signal through a photodetector and extracts the second harmonic component (2f component) after processing through a lock-in amplifier.

[0030] 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 spatial points for subsequent concentration inversion calculations.

[0031] The specific formula for calculating the initial concentration 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 location, is the absorption coefficient stored in the database, is the optical path length, is the upper limit of signal saturation.

[0032] 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.

[0033] In this implementation, 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 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 the harmonic signal 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 wavelength conditions has good physical consistency and cross-scene adaptability. The inversion mechanism supports independent calculation of each inspection location point, and combines vehicle movement to achieve high-spatial-resolution concentration reconstruction, providing a solid data foundation for subsequent leak judgment and positioning, and is particularly suitable for high-precision detection needs of medium and low-concentration target gases such as methane and ethane.

[0034] 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 the preset concentration threshold and the change rate threshold are as follows: reading the initial concentration value of the target gas at each inspection point, and performing adjacent concentration change analysis to obtain the initial concentration change rate between several groups of adjacent inspection points; comparing and analyzing 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).

[0035] In this implementation plan, 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 can 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.

[0036] Specifically, if Figure 2As shown, the target gas wind direction concentration data includes the initial concentration values of the target gas 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 of several directions are obtained respectively, and the initial concentration value of the target gas in each direction is corrected to obtain the corrected target gas concentration value in each direction at the abnormal inspection location point; based on the corrected target gas concentration value in each direction at the abnormal inspection location point, the leakage direction scores of several directions at the abnormal inspection location point are analyzed; the leakage direction scores of several directions at the abnormal inspection location point are compared and analyzed, and the direction corresponding to the maximum leakage direction score at the abnormal inspection location point is regarded as the predicted leakage direction of the target gas.

[0037] In this implementation plan, intelligent judgment of the direction of gas leakage at abnormal inspection locations is achieved, which significantly enhances the system's spatial perception capability and leakage response efficiency. By obtaining the initial concentration of target gas in multiple directions and combining it with environmental temperature, humidity, air pressure and other status data for correction processing, the concentration data is ensured to be comparable in multiple directions and multiple environments, eliminating the judgment error caused by differences in meteorological conditions. The system further constructs a direction scoring model based on the corrected concentration value, comprehensively analyzes the leakage trends in various directions, and finally selects the direction with the highest score as the predicted leakage direction, achieving a key breakthrough from concentration identification to direction inference. Compared with the traditional leakage judgment method without direction perception, this mechanism significantly improves the accuracy of leakage source tracking and response directionality, and is particularly suitable for urban inspection scenarios with complex multi-channels or significant wind field interference.

[0038] Specifically, the environmental status data includes environmental temperature values, environmental humidity values, and environmental pressure values. The specific steps for obtaining the target gas correction concentration value in each direction at the abnormal inspection location point are as follows: obtain the environmental status parameter data in each direction at the abnormal inspection location point, and the environmental status parameter data include the environmental temperature parameter value, the environmental humidity parameter value, and the environmental pressure parameter value; conduct a comprehensive analysis of the target gas initial concentration value in each direction at the abnormal inspection location point, combined with the environmental status data and environmental status parameter data of the corresponding direction, to obtain the target gas correction concentration value in each direction at the abnormal inspection location point.

[0039] Among them, the ambient temperature parameter value is obtained in the experiment by using gas detection equipment (such as laser absorption spectrometer) to measure the concentration of the target gas under different temperature conditions and recording the corresponding temperature values. By comparing the standard concentration with the actual measured concentration, the influence of temperature on the gas concentration measurement is analyzed, and the correction coefficient of ambient temperature to concentration is calculated using regression analysis, thereby obtaining the ambient temperature parameter value in each direction.

[0040] The ambient humidity parameter value is determined by conducting experiments under different humidity conditions, using gas detection equipment to measure the concentration of the target gas, and recording the corresponding humidity value. By comparing the difference between the gas concentration under different humidity conditions and the standard concentration, the influence of humidity on the concentration measurement is analyzed, and finally the humidity correction coefficient is obtained through regression analysis. These coefficients are used to correct the actual measured concentration to obtain the humidity parameter value.

[0041] The ambient pressure parameter value is obtained by measuring the gas concentration under different pressure conditions in the experiment, recording the gas concentration and corresponding pressure value under each pressure condition, analyzing the influence of pressure on concentration measurement by comparing with the standard concentration, and using regression analysis to obtain the pressure correction coefficient. Finally, the ambient pressure parameter value in each direction is obtained. These parameters can help to accurately correct the gas concentration in different pressure environments.

[0042] The specific formula for calculating the target gas correction concentration value in a certain direction at the abnormal inspection location is as follows: ;in, Correct the concentration value of the target gas in a certain direction at the abnormal inspection location. is the initial concentration value of the target gas in a certain direction at the abnormal inspection location, is the ambient temperature value in a certain direction at the abnormal inspection location. is the ambient temperature parameter value in a certain direction at the abnormal inspection location. is the temperature correction coefficient stored in the database, is the ambient humidity value in a certain direction at the abnormal inspection location. is the ambient humidity parameter value in a certain direction at the abnormal inspection location. is the humidity correction coefficient stored in the database, is the ambient air pressure value in a certain direction at the abnormal inspection location. is the ambient air pressure parameter value in a certain direction at the abnormal inspection location. is the barometric pressure correction factor stored in the database.

[0043] It should be explained that the temperature correction coefficients stored in the database , humidity correction factor , Barometric pressure correction factor The specific steps for obtaining the value are as follows: First, different temperature, humidity and air pressure conditions are selected in the experiment, the concentration of the target gas direction is measured and the ambient temperature, humidity and air pressure values are recorded. Then, based on these data, the difference between the actual measured value of the gas concentration under different environmental conditions and the standard concentration is compared, and the correction effect of temperature, humidity and air pressure on the concentration is calculated. Through regression analysis and fitting, the coefficient of concentration correction of each environmental factor is obtained. 、 、 ,Finally, these correction coefficients are stored in the database, and in the actual ,monitoring process, the corresponding correction coefficients are applied to adjust the gas ,concentration measurements according to the current temperature, humidity and air pressure conditions to ,ensure the accuracy of the concentration data under different ,environments.

[0044] The specific implementation example of calculating the target gas correction concentration value in a certain direction at the abnormal inspection location is as follows. The target gas is ethane gas and the existing parameters are as follows:

[0045] The initial concentration value of the target gas in a certain direction at the abnormal inspection location is approximately: 81.327ppm.

[0046] The ambient temperature value in a certain direction at the abnormal inspection location is approximately: 27.384℃.

[0047] The ambient temperature parameter value in a certain direction at the abnormal inspection location is approximately: 25.000℃.

[0048] The temperature correction factor stored in the database is approximately: 0.0023.

[0049] The ambient humidity value in a certain direction at the abnormal inspection location is approximately: 63.912%RH.

[0050] The reference value of the ambient humidity in a certain direction at the abnormal inspection location is approximately: 60.000%RH.

[0051] The humidity correction factor stored in the database is approximately: 0.0018.

[0052] The ambient air pressure value in a certain direction at the abnormal inspection location is approximately: 1014.102hPa.

[0053] The ambient air pressure parameter value in a certain direction at the abnormal inspection location is approximately: 1013.000hPa.

[0054] The barometric pressure correction factor stored in the database is approximately: 0.0015.

[0055] Substituting the above data into the specific formula for calculating the target gas correction concentration value in a certain direction at the abnormal inspection location point, we get:

[0056] The corrected target gas concentration value in a certain direction at the abnormal inspection location = 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.

[0057] The specific implementation examples of target gas correction concentration values in several directions at abnormal inspection locations are as follows. The existing data are as follows: including target gas correction concentration values in five directions (due north, due east, due south, due west, and northeast), the specific data are shown in Table 1 and Figure 3 As shown:

[0058] Table 1 Example of target gas correction concentration data in five directions at abnormal inspection locations

[0059]

[0060] In this implementation, a multidimensional correction mechanism for ambient temperature, humidity, and pressure is introduced to accurately correct the initial concentration of the target gas, ensuring that the concentration data has high consistency and physical credibility in different directions and environmental conditions. Compared with traditional measurement methods that ignore environmental interference factors, this solution first constructs an environmental state parameter dataset and combines the actual measured values of temperature, humidity, and pressure with the correction coefficients stored in the database to perform exponential bias correction, effectively eliminating the distortion of the gas concentration detection results caused by the external environment. 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. This has significant advantages in inspection scenarios with frequent wind field disturbances and large microenvironmental differences. In addition, the system supports actual parameter calculations using example data and outputs the corrected concentration trends in different directions. Combined with graphical visualization, it achieves a smooth transition from data correction to direction discrimination, providing a reliable input basis for subsequent leak direction scoring and source tracing. This mechanism is particularly critical in the high-precision monitoring of easily diffusible gases such as ethane, ensuring the accuracy and reliability of leak identification.

[0061] Specifically, the specific steps for analyzing the leakage direction scores of 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 for each direction at the abnormal inspection location point; comprehensively analyze the target gas correction concentration value for each direction at the abnormal inspection location point 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 for each direction at the abnormal inspection location point.

[0062] Among them, the target gas correction concentration parameter value 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 acquisition steps include: first, using a gas detection device (such as a laser absorption spectrometer) to measure the concentration of the target gas under different temperature, humidity and air pressure conditions, and recording the concentration value under each condition; then, by comparing the standard concentration with the actual measured concentration, analyzing the impact of environmental factors on the concentration measurement, and finally obtaining the corresponding target gas correction concentration parameter value.

[0063] The directional distance value represents the actual spatial distance between the abnormal inspection location point and the measurement points in each direction. The steps for obtaining it include: first, determining the precise coordinates of the abnormal inspection location point; then, determining the measurement points in each direction (for example, due north, due east, etc.) based on the inspection path planning; and finally, calculating the distance between the inspection location and the measurement point. This distance value is usually obtained using the Euclidean distance formula in three-dimensional space. The distance value reflects the spatial relationship between the measurement points in each direction and the abnormal inspection location point and is stored in the database for subsequent directional analysis and leakage direction scoring.

[0064] The direction angle value represents the relative azimuth from the abnormal inspection location to the target gas leakage point, and is used to describe the possible direction of the gas leakage. The acquisition steps include: first, it is necessary to determine the coordinates of the abnormal inspection location and the location of the target gas leakage source, and calculate the azimuth angle between the target gas leakage point and each measurement point through the azimuth sensor or angle measuring instrument of the inspection equipment. The angle value represents the relative direction of each direction to 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.

[0065] The wind direction angle value is used to describe the current wind direction. The wind direction has an important influence on gas diffusion and concentration distribution. The steps for obtaining 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. The current wind direction angle is obtained through the measurement data of the wind speed and direction instrument. After necessary corrections, the value is stored in the database. In gas leak monitoring, the wind direction angle value will serve as an important correction parameter, affecting the direction of gas diffusion and concentration distribution.

[0066] The specific steps for calculating the leakage direction score in a certain direction at an abnormal inspection location are as follows: ;in, Leakage direction score of a certain direction at the abnormal inspection location point, Correct the concentration value of the target gas in a certain direction at the abnormal inspection location. Correction concentration parameter value of target gas in a certain direction at abnormal inspection location. is the directional distance value in a certain direction at the abnormal inspection location point, is the distance adjustment coefficient stored in the database, is the direction angle value of a certain direction at the abnormal inspection location point, is the wind direction angle value in a certain direction at the abnormal inspection location point, It is the wind direction adjustment coefficient stored in the database.

[0067] It should be explained that the distance adjustment coefficient stored in the database , wind direction adjustment coefficient The specific acquisition steps are as follows: first, select multiple different measurement distances and wind direction conditions, record the change in 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.

[0068] In this implementation, a leak direction scoring model is constructed by introducing multidimensional factors, enabling scientific assessment and accurate determination of potential leak directions at abnormal inspection locations. This significantly improves the system's ability to identify leak directions in complex environments. The system comprehensively considers the corrected target gas concentration value, the degree of deviation from the standard parameter value, the directional distance value, the azimuth angle value, and the current wind direction angle value in each direction. Distance and wind direction adjustment coefficients derived from regression fitting of measured data are introduced, making the scoring results more consistent with actual gas diffusion patterns. Compared with methods that rely solely on absolute concentration values, this method effectively avoids misjudgments or directional distortions caused by factors such as local wind disturbances and terrain shielding. The directional distance value quantifies the spatial attenuation of the leak source probability, while the coupled analysis of the azimuth angle and wind direction angle value identifies the likely main propagation path of the gas. The scoring formula is flexible and can be expanded to include comprehensive analysis of multiple directions and branching paths, making it highly adaptable to scenarios with complex wind fields or uneven target diffusion. Ultimately, the system infers the main leak direction based on the maximum score, enhancing the system's perception of leak trends and providing clear guidance for subsequent telemetry scanning and point locking.

[0069] Specifically, 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 in the gas leakage area image at several time points.

[0070] The specific steps for obtaining the target gas leakage point location information are as follows: reading the remote sensing concentration distribution data and image data at the target gas predicted leakage direction and preprocessing them respectively; initializing a preset gas diffusion model (a Gaussian diffusion model in this embodiment) and running the preset gas diffusion model; combining the remote sensing concentration distribution data and image data at the target gas predicted leakage direction with the running results of the preset gas diffusion model to jointly analyze and determine the target gas leakage point location information. The specific example steps are as follows:

[0071] The inspection vehicle uses a pan-tilt QCL laser detection device (wavelength: 3345nm) and a near-infrared ethane-specific module (1680nm) to perform telemetry scanning of the target area, collecting data from multiple measurement points at several time points. The data includes:

[0072] 2D coordinates of each measurement point (e.g. GPS projection coordinates);

[0073] The methane concentration value of the location at a certain moment (unit: ppm);

[0074] Ethane concentration value at the same moment (unit: ppm);

[0075] Synchronously collect infrared images or optically enhanced images of the gas leakage area to form a gas cloud map. Each frame of the image contains:

[0076] Grayscale values of several pixels in the leakage area (indicating absorption intensity or thermal anomaly);

[0077] The 2D image coordinates of each pixel;

[0078] Pixel timestamps are time-aligned with corresponding concentration data;

[0079] Environmental parameter correction;

[0080] Three corrections are made to the original concentration values:

[0081] Use the ambient temperature, humidity, and air pressure parameters + current environmental parameters to call the correction coefficients stored in the database for concentration calibration;

[0082] Example: The original methane concentration is 81.327 ppm, which becomes 79.672 ppm after correction by the temperature and humidity factors.

[0083] A similar correction was also made for the ethane concentration;

[0084] Preprocess the image data, including:

[0085] Image denoising: Gaussian filtering is used to remove background disturbances;

[0086] Contrast enhancement: Enhance the grayscale changes at the edge of the cloud to extract the concentration boundary;

[0087] Pixel value mapping: construct a pseudo-color concentration map based on the pixel value-concentration mapping relationship;

[0088] Coordinate alignment: Use the camera calibration matrix or spatial mapping relationship to map the image 2D coordinates to the actual GPS plane coordinates to ensure that the image pixels coincide with the concentration measurement points in space;

[0089] Leaked gas type: methane, ethane (different molecular mass and specific gravity);

[0090] Leakage type selection: continuous small flow leakage;

[0091] Wind speed setting: for example, 1.8m / s; wind direction setting is 15° north of due east;

[0092] The lateral diffusion coefficient and vertical diffusion coefficient are set according to the Pasquill stability category;

[0093] Initial concentration: Use the maximum concentration in the telemetry data or 90% of it as the initial concentration;

[0094] Run the simulation and output the predicted concentration distribution (spatial grid matrix) at each time step;

[0095] Calculate the gas concentration contours, centerline trajectories, and main diffusion paths at each simulation time point;

[0096] Concentration map compared with simulation:

[0097] Perform point matching between remote sensing concentration distribution and Gaussian model output;

[0098] Compare the overlap between 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 agreement;

[0099] If the difference is large, adjust the model parameters (wind speed, diffusion coefficient);

[0100] Comparison of image data and model:

[0101] Compare the morphological contours of the gas cloud in the image with the diffusion contours in the Gaussian model;

[0102] Combined with pixel density mapping data, analyze whether the image density distribution is consistent with the simulation;

[0103] The cloud expansion speed and direction obtained by image inversion are used to assist in verifying the rationality of wind direction setting;

[0104] Leak point reverse positioning:

[0105] Find the measurement point with the most dramatic concentration change in the remote sensing concentration data;

[0106] Determine the concentration gradient is reversed, that is, the direction of flow against the suspected leak source;

[0107] Triangulation method: take three high-concentration measurement points, intersect them with the concentration gradient direction as the vector, and calculate the coordinates of the intersection as the initial estimate of the leakage point;

[0108] Image-assisted verification: confirm whether the point in the concentration map is located in the gas cloud source area;

[0109] Database records:

[0110] The final leakage point two-dimensional coordinates, concentration time series, wind direction data, model parameters, and image frame numbers are all written into the database;

[0111] Used to form leakage event archives and future retrospective analysis;

[0112] Report output:

[0113] Including leak point coordinates (WGS84 / Gauss plane coordinates), gas type (methane or ethane), and maximum concentration value.

[0114] In this implementation plan, this part of the content achieves high-precision positioning of the leakage point location information by constructing a complete set of remote sensing concentration distribution data and image data fusion analysis mechanism, combined with environmental correction and gas diffusion model simulation, which has significant practical and innovative advantages. On the one hand, this method is based on the simultaneous remote sensing of methane and ethane by laser absorption spectroscopy, integrating the leakage cloud morphology information extracted from infrared images or optical images, and establishing a synchronous alignment mechanism at the time and space levels to ensure high consistency between the image pixel concentration value and the actual remote sensing point concentration value; on the other hand, by introducing the physical correction formula of the three factors of temperature, humidity and air pressure, the influence of external environmental disturbances on the measurement accuracy is eliminated, and the accuracy of concentration inversion is effectively improved. In the process of determining the leakage location, the Gaussian diffusion model is used for simulation. Through multi-dimensional matching of the model with the actual concentration field and the image air mass morphology, the accuracy of leakage path judgment and leakage source inversion is greatly improved. Finally, the triangulation positioning method is used to output the precise spatial coordinates of the leakage point, providing verifiable and traceable technical support for the fixed-point tracing and response intervention of industrial gas leaks.

[0115] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0116] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A vehicle-mounted pan-tilt laser telemetry scanning gas leak location system, characterized in that: include: A data acquisition unit is used to obtain the laser absorption second harmonic signal intensity of a plurality of inspection positions of the inspection vehicle on a set inspection route; A concentration inversion processing unit is used to invert the initial concentration value of the target gas at each inspection position based on the intensity of the laser absorption second harmonic signal; A concentration analysis unit is used to compare the concentration change rate of the target gas between adjacent inspection locations and identify abnormal inspection locations based on preset concentration thresholds and change rate thresholds; The leakage direction analysis unit is used to obtain the target gas wind direction concentration data at the abnormal inspection location 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 of the target gas in the predicted leakage direction, and conduct joint analysis in combination with the preset gas diffusion model to obtain the leakage point location information of the target gas; The target gas wind direction concentration data includes the initial concentration values of the target gas in several directions. The specific steps for determining the predicted leakage direction of the target gas are as follows: For abnormal inspection locations, 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; Analyze the leakage direction scores of several directions at the abnormal inspection location based on the target gas correction concentration value in each direction at the abnormal inspection location; Compare and analyze the leakage direction scores of several directions at the abnormal inspection location point, and regard the direction corresponding to the maximum leakage direction score at the abnormal inspection location point as the predicted leakage direction of the target gas; The specific steps for analyzing the leakage direction scores in several directions at abnormal inspection locations 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 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; The specific formula for calculating the leakage direction score in a certain direction at an abnormal inspection location is as follows: ； in, 、 、 、 、 、 The following are the leakage direction score, target gas correction concentration value, target gas correction concentration parameter value, direction distance value, direction angle value, and wind direction angle value of a certain direction at the abnormal inspection location point. 、 They are the distance adjustment coefficient and wind direction adjustment coefficient stored in the database respectively.

2. The vehicle-mounted pan-tilt laser telemetry scanning gas leak location system according to claim 1 is characterized in that: The specific steps for inverting the initial concentration of the target gas at each inspection location based on the intensity of the laser absorption second harmonic signal are as follows: Obtain the signal saturation upper limit value and optical path length value; The laser absorption second harmonic signal intensity at each inspection position is combined with the signal saturation upper limit 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 2 is characterized in that: The specific formula for calculating the initial concentration 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 location, 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 location system according to claim 1 is characterized in that: The specific steps for comparing the concentration change rates of the target gas between adjacent inspection locations and identifying abnormal inspection locations 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 location, and perform adjacent concentration change analysis to obtain the initial concentration change rate between several groups of adjacent inspection locations; 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 locations is higher than the preset concentration threshold, it is considered an abnormal inspection location.

5. The vehicle-mounted pan-tilt laser telemetry scanning gas leak location system according to claim 1 is characterized in that: The environmental status data includes the ambient temperature value, the ambient humidity value, and the ambient pressure value. The specific steps for obtaining the target gas correction concentration value in each direction at the abnormal inspection location are as follows: Acquire 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.

6. 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 in the gas leakage area image at several time points.

7. The vehicle-mounted pan-tilt laser telemetry scanning gas leak location system according to claim 1 is characterized in that: The specific steps to obtain the target gas leakage 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 pre-process them 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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