Tunnel Gas Detection Method and System Combining Geological Information and Hyperspectral Detection

Abstract

This invention belongs to the field of tunnel gas detection technology, specifically disclosing a tunnel gas detection method and system that combines geological information and hyperspectral detection. The method includes: acquiring spectral image data and image data of the tunnel face; extracting the spectral reflectance of each pixel in the spectral characteristic band, comparing the spectral reflectance with the reflectance in a standard gas spectral database and a standard mineral spectral database to determine the gas type and mineral type corresponding to each pixel; establishing a gas storage layer based on the correspondence between the gas type and mineral type at each pixel location; obtaining the fracture distribution of the gas storage layer based on the image data of the tunnel face to establish an escape layer; calculating the gas reserves and gas escape rate in each gas storage layer, and generating a detection report. This invention jointly determines the gas type by the correlation between minerals and gases, and can complete logical self-consistency verification while detecting, increasing the accuracy of gas category detection.

Description

Technical Field

[0001] This invention relates to the field of tunnel gas detection technology, and in particular to a tunnel gas detection method and system that combines geological information and hyperspectral detection. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Harmful gases may escape during tunnel construction. In order to detect the escape of harmful gases in real time, predict the storage and transportation of harmful gases in the geological body, and predict and mitigate the adverse effects of harmful gases on the construction process and the safety of construction personnel and equipment, gas detection in tunnels is an important means.

[0004] In existing technologies, tunnel gas detection mainly relies on installing various detectors in the space or facilities behind the tunnel face to detect the dispersion of harmful gases. However, the method of using detectors for tunnel gas detection often has the following technical problems: (1) The detection range of the detection instruments is limited to the excavated and exposed tunnel space and surface. They cannot detect the unexcavated part in front of the tunnel face and are powerless to detect the gas still stored in the rock fissures or fault spaces. (2) The gas detection process is easily affected by sensitive factors such as external environmental humidity and temperature, which affects the accuracy of gas detection. Furthermore, the current mainstream tunnel gas detection instruments all start from the properties of the gas itself and ignore the correlation between gas-producing minerals and gas types. They cannot form a self-consistent logic in gas production, and there are always loopholes in the accuracy and authenticity of the detection.

[0005] (3) Existing detection instruments can only perform single-point detection. If gas escape detection is to be performed on the entire working face, multiple devices or multiple points need to be repeatedly tested, which is time-consuming and laborious. Furthermore, the instruments cannot provide location information during detection, which makes it difficult to fully understand the gas escape situation of the target detection surface. Summary of the Invention

[0006] To address the aforementioned issues, this invention proposes a tunnel gas detection method and system that combines geological information and hyperspectral detection. Based on thermal infrared hyperspectral imaging technology, it simultaneously acquires gas spectral and geological spectral information. While detecting the types of escaping gases, it identifies the geometric features and constituent minerals of the gas storage and transportation space, thereby inferring the types of gases that may be produced. This achieves simultaneous detection of gas types and their storage and migration.

[0007] In some implementations, the following technical solutions are adopted: A tunnel gas detection method combining geological information and hyperspectral detection includes: Acquire spectral image data and image data of the working face; The spectral reflectance of each pixel in the spectral characteristic band is extracted based on the spectral image data. The spectral reflectance is then compared with the reflectance in the standard gas spectral database and the standard mineral spectral database to determine the gas type and mineral type corresponding to each pixel. Based on the correspondence between gas type and mineral type at each pixel location, a gas storage layer is established; based on the image data of the working face, the fracture distribution of the gas storage layer is obtained, and an escape layer is established. Calculate the gas reserves and gas escape rate in each gas reservoir, and generate a detection report.

[0008] As a further approach, the spectral reflectance of each pixel in the spectral feature bands is extracted based on the spectral image data, specifically as follows: Radiometric calibration is performed on the spectral data of the working face to establish the relationship between the original measurement signal and the radiance value, and the radiance value is calculated from the original measurement signal; The conversion from radiance value to reflectance is achieved using the standard plate reflectance calibration method. Establish the reflectance spectrum of the face image; thereby obtaining the spectral reflectance of each pixel in the spectral image, and further obtaining the spectral reflectance of each pixel in the spectral characteristic band.

[0009] As a further step, the relationship between the original measurement signal and the radiance value is established, specifically as follows: ; ; Where L is the radiance value and R is the original measurement signal. As calibration coefficients, diffuse reflection standard plates are used to calibrate the radiance, R. 标准板 It is the measurement signal of the standard board, R 暗电流 It is a dark current signal, ρ 标准板 It is the known reflectivity of the standard plate.

[0010] As a further solution, a standard plate reflectivity calibration method is used to convert radiance values ​​to reflectivity, specifically: ; Where ρ is the reflectivity of the target region, and L s This is the radiance value obtained from a normal measurement of the target area, L. p It is the radiance value obtained by measuring the standard plate, L d It is the radiance value obtained by measuring the target area when the radiation source is turned off.

[0011] As a further approach, a gas storage layer is established based on the correspondence between gas types and mineral types at each pixel location, specifically as follows: Determine whether the gas type at each pixel location corresponds to the gas produced by the mineral at that pixel. If so, determine that this area is a gas reservoir and label the gas type and reservoir area S. c All the gas storage layers constitute the gas storage layer.

[0012] As a further solution, an escaping layer is created, specifically as follows: The image data of the working face is processed by grayscale and binarization to obtain the geometric shape, area and location distribution of the fractures, and then the fracture distribution of the gas storage layer is obtained. Determine whether the gas concentration at each fracture location in the gas storage layer shows a decreasing trend outward. If so, the corresponding fracture is an escape layer, and the location of the escape port and gas information are marked; all escape layers constitute an escape layer.

[0013] As a further step, it is necessary to determine whether the gas concentration at each fracture location in the gas storage layer shows a decreasing trend outwards, specifically: Calculate the spectral reflectance gradient of the corresponding gas at the fracture. Calculate the fracture length by connecting the two endpoints of the fracture with the longest straight-line distance, and take the midpoint of this line as the center of the circle. The calculation range is a perfect circle with a diameter of three-half of the fracture length, and the gradient direction is eight equally divided radial directions starting from the center of the circle. f(x) is the spectral reflectance gradient function, and the formula is as follows: ; Where, ρ i To calculate the spectral reflectance measured at the i-th pixel in the direction, x i To calculate the distance from the i-th pixel in a direction to the starting point, n is the number of pixels in that direction; For all pixels in each direction, the spectral reflectance gradient is calculated sequentially. If there are at least six adjacent directions where the value of f(x) is positive for any i, it indicates that the spectral reflectance increases from the crack outwards, that is, the gas concentration decreases from the crack outwards.

[0014] As a further step, the gas reserves in each gas reservoir are calculated, specifically: Multiple rock samples were taken in an equilateral triangle within a gas reservoir. The porosity of each rock sample was measured, and the average porosity of all rock samples was calculated as the porosity of the gas reservoir. Based on the porosity and area of ​​the gas reservoir, calculate the volume of the pores in the gas reservoir. Calculate the volume of the fractures in the gas reservoir based on the fracture area of ​​the gas reservoir. Based on the volume of the pores and the volume of the fractures in the gas reservoir, the gas reserves in the gas reservoir are calculated. The gas reserves in each gas reservoir are calculated using the process described above.

[0015] As a further step, the gas escape rate within each gas reservoir is calculated, specifically: ; ; Where v is the velocity of the gas relative to the spectrometer. This represents the reduction in wavelength within the band containing the absorption peak. The standard wavelength for the absorption peak band. At the speed of light, This refers to the observation wavelength in the band where the absorption peak is located.

[0016] In other embodiments, the following technical solutions are adopted: A tunnel gas detection system combining geological information and hyperspectral detection includes: The acquisition module is used to acquire spectral image data and image data of the working face; The classification module is used to extract the spectral reflectance of each pixel in the spectral feature band based on the spectral image data, and compare the spectral reflectance with the reflectance in the standard gas spectral database and the standard mineral spectral database to determine the gas type and mineral type corresponding to each pixel. The analysis module is used to establish a gas storage layer based on the correspondence between gas types and mineral types at each pixel location; and to establish an efflux layer based on the fracture distribution of the gas storage layer obtained from the image data of the working face. The generation module is used to calculate the gas reserves and gas escape rate in each gas reservoir and generate a detection report.

[0017] Compared with the prior art, the beneficial effects of the present invention are: (1) This invention determines the gas type by jointly identifying the correlation between minerals and gases. This allows for logical consistency verification during detection, increasing the accuracy of gas type detection. Furthermore, if the detection results are abnormal and the mineral and gas detection results are inconsistent, problems can be identified promptly, reducing potential risks from unknown factors.

[0018] (2) This invention predicts the gas stored in unexcavated geological bodies through geological structure, enabling advanced prediction of gas information. By using information such as the gas reserves, type, and location in the geological body ahead, time can be saved for engineering operations, providing timely and effective reference for formulating reasonable and effective prevention, treatment, and operation plans.

[0019] (3) The present invention supplements the spatial information of gas escape by geological information, which can assist relevant personnel in making targeted decisions and precise operations; the obtained gas escape vent and gas storage layer location information can provide effective reference for precise sealing and gas transmission and guiding facilities, and improve processing efficiency.

[0020] Other features and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] Figure 1 This is a flowchart of a tunnel gas detection method that combines geological information and hyperspectral detection in an embodiment of the present invention. Detailed Implementation

[0022] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0023] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0024] Example 1 In one or more embodiments, a tunnel gas detection method combining geological information and hyperspectral detection is disclosed, combining... Figure 1 Specifically, it includes the following processes: S101: Acquire spectral image data and image data of the working face.

[0025] S102: Extract the spectral reflectance of each pixel in the spectral feature band based on the spectral image data, and compare the spectral reflectance with the reflectance in the standard gas spectral database and the standard mineral spectral database to determine the gas type and mineral type corresponding to each pixel.

[0026] It should be noted that the bands where reflectance changes abruptly are the characteristic bands. The characteristic bands of each mineral are predetermined and can be found in mineral spectral databases. These databases are mature and publicly available, such as the USGS spectral database. This database stores almost all information about each gas, including its spectral name, molecular formula, spectrum, and spectral reflectance. It also stores almost all information about each mineral, including its spectral name, molecular formula, spectrum, composition ratio, and spectral reflectance.

[0027] In this embodiment, the spectral reflectance of each pixel in the spectral feature band is extracted based on the spectral image data. The specific process is as follows: S1021: Perform radiometric calibration on the spectral data of the working face, establish the relationship between the original measurement signal and the radiance value, and calculate the radiance value through the original measurement signal; Specifically, the spectral data of the tunnel face are radiometrically calibrated using preset calibration parameters to establish the relationship between the original measurement signal and the radiance value. The radiance value can then be calculated from the original measurement signal using the following formula: ; ; Where L is the radiance value and R is the original measurement signal. As calibration coefficients, diffuse reflection standard plates are used to calibrate the radiance, R. 标准板 It is the measurement signal of the standard board, R 暗电流 It is a dark current signal, ρ 标准板 It is the known reflectivity of the standard plate.

[0028] S1022: The conversion from radiance value to reflectance is achieved using the standard plate reflectance calibration method; the specific formula is as follows: ; Where ρ is the reflectivity of the target region, and L s It is the radiance value obtained from normal measurement of the target area (i.e., the radiance value corresponding to the original measurement signal), L p It is the radiance value obtained by measuring the standard plate, L d It is the radiance value obtained by measuring the target area when the radiation source is turned off.

[0029] S1023: Establish the reflectance spectrum of the face image; thereby obtaining the spectral reflectance of each pixel in the spectral image, and then obtaining the spectral reflectance of each pixel in the spectral characteristic band.

[0030] Furthermore, the spectral reflectance is compared with the reflectance in the standard gas spectral database and the standard mineral spectral database to determine the gas type and mineral type corresponding to each pixel, specifically: Calculate the correlation coefficient between the spectral reflectance of a pixel in a spectral feature band and the reflectance in a standard gas spectral database. Select the band with the largest correlation coefficient in the standard gas spectral database, and the gas type corresponding to this band is taken as the gas type corresponding to the pixel. Calculate the correlation coefficient between the spectral reflectance of a pixel in a spectral feature band and the reflectance in a standard mineral spectral database. Select the band with the largest correlation coefficient in the standard mineral spectral database, and the mineral type corresponding to this band is taken as the mineral type corresponding to the pixel.

[0031] By performing the above operation on each pixel, we obtain pixel-level precision data on the distribution of mineral and gas categories.

[0032] Based on the obtained data, gas and mineral category partitioning layers are created on the image, specifically: ① Establish category-color labels, with each gas or mineral category corresponding to a color, and assign color labels based on the category labels in the data; ② In MATLAB, the bwlabel function is used to label connected regions composed of each color pixel, and the label is the corresponding gas or mineral category.

[0033] After the above transformation from "pixel name label - pixel color label - area name label", you can get an intuitive gas and mineral category partition layer that uses color to delineate areas and displays names at the same time.

[0034] S103: Based on the correspondence between gas type and mineral type at each pixel location, establish a gas storage layer; based on the image data of the working face, obtain the fracture distribution of the gas storage layer and establish an escaping layer.

[0035] In this embodiment, the process of establishing the gas storage layer is as follows: Determine whether the gas type at each pixel location corresponds to the gas produced by the mineral at that pixel. If so, determine that this area is a gas reservoir and label the gas type and reservoir area S. c All the gas storage layers constitute the gas storage layer.

[0036] Specifically, based on the obtained pixel-level mineral and gas category distribution data, the labels in the data are checked. The checking criterion is: whether the label name contained in the pixel data has a chemical relationship of "gas - gas-producing mineral". If it exists, the pixel is determined to be contained in the gas-producing layer of that type of gas, and the pixel location is a gas storage layer; otherwise, it is not a gas storage layer. Each gas storage layer operates in parallel, and the data is stored in separate areas to ensure that there is no interference between gas storage layers.

[0037] All pixels identified as containing the chemical relationship are labeled, with the gas names that conform to the above chemical relationship highlighted separately.

[0038] Perform the conversion operation of "pixel name label - pixel color label - region name label" using the same method as in S102 to generate the gas storage layer.

[0039] In this embodiment, the process of creating the escaping layer is as follows: S1031: Perform grayscale and binarization processing on the image data of the tunnel face to obtain the geometry and area S of the fracture. l And the location distribution, thus obtaining the fracture distribution of the gas storage layer; Since the cracks appear as dark shadows, you can start by selecting a small number when setting the binarization threshold, until the cracks are completely connected and no blocky black areas appear.

[0040] Because a point source is used during spectral scanning, and the light rays are not perpendicular to the tunnel face, the cracks will appear as distinct dark shadows. The geometry and area S of the cracks can be represented using binarization segmentation. l and location distribution.

[0041] S1032: Determine whether the gas concentration at each fracture location in the gas storage layer shows a decreasing trend outward. If so, the corresponding fracture is an escape layer, and the location of the escape port and gas information are marked; all escape layers constitute an escape layer.

[0042] In this embodiment, two necessary conditions must be met to determine that the crack is a gas escape outlet: (1) The fracture is located within the gas reservoir area; (2) At the fracture location, the gas concentration of the gas reservoir shows a decreasing trend outward.

[0043] In this embodiment, the specific process for determining whether the gas concentration at each fissure location in the gas storage layer shows a decreasing trend outward is as follows: Calculate the spectral reflectance gradient of the corresponding gas at the fracture. Calculate the fracture length by connecting the two endpoints of the fracture with the longest straight-line distance, and take the midpoint of this line as the center of the circle. The calculation range is a perfect circle with a diameter of three-half of the fracture length, and the gradient direction is eight equally divided radial directions starting from the center of the circle. f(x) is the spectral reflectance gradient function, and the formula is as follows: ; Where, ρ i To calculate the spectral reflectance measured at the i-th pixel in the direction, x i To calculate the distance from the i-th pixel in a direction to the starting point, n is the number of pixels in that direction.

[0044] For all pixels in each direction, the spectral reflectance gradient is calculated sequentially. If there are at least six adjacent directions where the value of f(x) is positive for any i, it indicates that the spectral reflectance increases from the crack outwards, that is, the gas concentration decreases from the crack outwards.

[0045] When the above two conditions are met, the crack is determined to be the vent of the corresponding gas, the corresponding crack is the vent layer, and the location of the vent and gas information are marked; all vent layers constitute the vent layer.

[0046] S104: Calculate the gas reserves and gas escape rate in each gas reservoir and generate a detection report.

[0047] It should be noted in advance that the following calculations are performed for a single gas to calculate the reserves and reserves of that gas, expressed in terms of volume and volume percentage, respectively.

[0048] In this embodiment, the process of calculating the gas reserves in each gas storage layer is as follows: S1041: Take multiple rock samples in an equilateral triangle within a gas reservoir; Specifically, the density method is used to determine the porosity of the rock. Rock samples are taken in an equilateral triangle within the same gas reservoir area for measurement. When selecting the location, if there is an vent on the surface, sampling points are arranged around the vent; if there is no vent, sampling points are arranged around the centroid of the gas reservoir surface.

[0049] S1042: Measure the porosity of each rock sample, calculate the average porosity of all rock samples, and use this average as the porosity of the gas reservoir. f ; Porosity f The calculation formula is:

[0050] Where, ρ 样品 ρ is the apparent density of the sample. 骨架 This represents the skeleton density of the sample.

[0051] S1043: Based on the porosity of the gas storage layer f and gas reservoir area S c Calculate the volume of the pores in the gas reservoir; Specifically, it is assumed that the porosity of the gas-bearing reservoir rock changes very little within a unit length of 1m. Under this condition, based on the already obtained reservoir area... S c Calculate the pore volume of the gas reservoir within a 1m range forward of the entire face of the tunnel. V k : ; f The porosity of the gas reservoir is denoted as .

[0052] S1044: Calculate the volume of the fractures in the gas reservoir based on the fracture area of ​​the gas reservoir; Specifically, it is assumed that the crack volume changes very little within a unit length of 1m. Under this condition, based on the already obtained crack area... S l Calculate the volume V of the fissure within 1m in front of the tunnel face. l : .

[0053] S1045: Based on the volume of pores and fractures in the gas reservoir, the gas reserves within the reservoir are calculated. The specific calculation formula is as follows: .

[0054] The proportion of this gas in reserves is: ;α AB Let AB be the proportion of gas AB to the total gas volume, and V be the total gas storage per unit length in front of the face ...

[0055] S1046: Calculate the gas reserves and reserves percentage for each gas reservoir according to the above process.

[0056] In this embodiment, the process of calculating the gas escape rate in each gas storage layer is as follows: For gases in an escaped state, there is a tendency for them to move closer to the spectrometer. This movement causes the wavelength of the received absorption spectrum to shorten, i.e., a blue shift. Based on the Doppler effect, the velocity of the gas relative to the spectrometer, i.e., the escape velocity, can be calculated from the amount of wavelength shortening. The formula is: ; ; Where v is the velocity of the gas relative to the spectrometer. This represents the reduction in wavelength within the band containing the absorption peak. The standard wavelength for the absorption peak band. At the speed of light, This refers to the observation wavelength in the band containing the absorption peak. Standard wavelengths can be found in gas spectral databases, while the observation wavelength is the wavelength in the band containing the absorption peak observed by the spectrometer.

[0057] After the calculation is completed, the calculated escaping velocity is added to the escaping layer.

[0058] The combined information is used to characterize the basic information detected, the storage and dissipation of the gas, and to generate a detection report, including: (1) Representing basic information: The basic information includes gas categories, mineral categories, and pixel areas for each gas and mineral, as well as the coordinates and spectral information contained within the pixels themselves. This information is represented by partitioned layers for each gas and mineral category.

[0059] (2) Characterizing gas storage conditions: Gas storage information includes the storage areas for each type of gas, the storage volume, and the percentage of each gas's storage volume relative to the total gas storage volume. This information is represented by a gas storage layer.

[0060] (3) Characterize the dissipation situation; The dispersion details include the size and shape of the vents for various gases, their location, and the dispersion velocity. This information is represented by a dispersion layer.

[0061] The detection report is structured in a "3+1+1" manner. "3+1+1" refers to three layers, one image, and a data list. The three layers include a gas and mineral category zoning layer, a gas storage layer, and an escape layer. Each layer is presented separately, and the data is stored independently to ensure clarity and prevent confusion. The image refers to the pixel image of the tunnel face taken by the imaging module on the spectrometer. It not only identifies fractures but also serves as the base image for establishing each layer. The data list refers to the pixel spectral data after a series of label additions and calculations, including important information such as the pixel's coordinates, spectrum, and label.

[0062] This embodiment, by obtaining information such as the gas reserves, type, and location in the geological body ahead, can gain time for engineering operations and provide timely and effective reference for formulating reasonable and effective prevention, treatment, and operation plans. Supplementing the spatial information of gas escape with geological information can assist relevant personnel in targeted decision-making and precise operations; the obtained location information of gas escape vents and gas storage layers can provide effective reference for precise sealing and the construction of gas transmission and guiding facilities, improving processing efficiency.

[0063] Example 2 In one or more embodiments, a tunnel gas detection system combining geological information and hyperspectral detection is disclosed, comprising: The acquisition module is used to acquire spectral image data and image data of the working face; The classification module is used to extract the spectral reflectance of each pixel in the spectral feature band based on the spectral image data, and compare the spectral reflectance with the reflectance in the standard gas spectral database and the standard mineral spectral database to determine the gas type and mineral type corresponding to each pixel. The analysis module is used to establish a gas storage layer based on the correspondence between gas types and mineral types at each pixel location; and to establish an efflux layer based on the fracture distribution of the gas storage layer obtained from the image data of the working face. The generation module is used to calculate the gas reserves and gas escape rate in each gas reservoir and generate a detection report.

[0064] The specific implementation methods of the above modules are the same as those in Example 1, and will not be described in detail again.

[0065] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A tunnel gas detection method combining geological information and hyperspectral detection, characterized in that, include: Acquire spectral image data and image data of the working face; The spectral reflectance of each pixel in the spectral characteristic band is extracted based on the spectral image data. The spectral reflectance is then compared with the reflectance in the standard gas spectral database and the standard mineral spectral database to determine the gas type and mineral type corresponding to each pixel. Based on the correspondence between gas type and mineral type at each pixel location, a gas storage layer is established; based on the image data of the working face, the fracture distribution of the gas storage layer is obtained, and an escape layer is established. Based on the correspondence between gas type and mineral type at each pixel location, a gas storage layer is established, specifically as follows: Determine whether the gas type at each pixel location corresponds to the gas produced by the mineral at that pixel. If so, determine that this area is a gas reservoir and label the gas type and reservoir area S. c All the gas storage layers constitute the gas storage layer. Create an escaping layer, specifically as follows: The image data of the working face is processed by grayscale and binarization to obtain the geometric shape, area and location distribution of the fractures, and then the fracture distribution of the gas storage layer is obtained. Determine whether the gas concentration at each fracture location in the gas storage layer shows a decreasing trend outward. If so, the corresponding fracture is an escape layer, and the location of the escape port and gas information are marked; all escape layers constitute an escape layer. Calculate the gas reserves and gas escape rate in each gas reservoir, and generate a detection report.

2. The tunnel gas detection method combining geological information and hyperspectral detection as described in claim 1, characterized in that, The spectral reflectance of each pixel in the spectral feature bands is extracted based on the spectral image data, specifically as follows: Radiometric calibration is performed on the spectral data of the working face to establish the relationship between the original measurement signal and the radiance value, and the radiance value is calculated from the original measurement signal; The conversion from radiance value to reflectance is achieved using the standard plate reflectance calibration method. Establish the reflectance spectrum of the facet image; This allows us to obtain the spectral reflectance of each pixel in the spectral image, and further obtain the spectral reflectance of each pixel in the spectral characteristic band.

3. The tunnel gas detection method combining geological information and hyperspectral detection as described in claim 2, characterized in that, The relationship between the original measurement signal and the radiance value is established as follows: ； ； Where L is the radiance value and R is the original measurement signal. As calibration coefficients, diffuse reflection standard plates are used to calibrate the radiance, R. 标准板 It is the measurement signal of the standard board, R 暗电流 It is a dark current signal, ρ 标准板 It is the known reflectivity of the standard plate.

4. The tunnel gas detection method combining geological information and hyperspectral detection as described in claim 2, characterized in that, The conversion from radiance to reflectance is achieved using a standard plate reflectance calibration method, specifically as follows: ； Where ρ is the reflectivity of the target region, and L s This is the radiance value obtained from a normal measurement of the target area, L. p It is the radiance value obtained by measuring the standard plate, L d It is the radiance value obtained by measuring the target area when the radiation source is turned off.

5. The tunnel gas detection method combining geological information and hyperspectral detection as described in claim 1, characterized in that, To determine whether the gas concentration at each fracture location in the gas storage layer shows a decreasing trend outwards, specifically: Calculate the spectral reflectance gradient of the corresponding gas at the fracture. Calculate the fracture length by connecting the two endpoints of the fracture with the longest straight-line distance, and take the midpoint of this line as the center of the circle. The calculation range is a perfect circle with a diameter of three-half of the fracture length, and the gradient direction is eight equally divided radial directions starting from the center of the circle. f(x) is the spectral reflectance gradient function, and the formula is as follows: ； Where, ρ i To calculate the spectral reflectance measured at the i-th pixel in the direction, x i To calculate the distance from the i-th pixel in a direction to the starting point, n is the number of pixels in that direction; For all pixels in each direction, the spectral reflectance gradient is calculated sequentially. If there are at least six adjacent directions where the value of f(x) is positive for any i, it indicates that the spectral reflectance increases from the crack outwards, that is, the gas concentration decreases from the crack outwards.

6. The tunnel gas detection method combining geological information and hyperspectral detection as described in claim 1, characterized in that, The gas reserves in each gas reservoir are calculated as follows: Multiple rock samples were taken in an equilateral triangle within a gas reservoir. The porosity of each rock sample was measured, and the average porosity of all rock samples was calculated as the porosity of the gas reservoir. Based on the porosity and area of ​​the gas reservoir, calculate the volume of the pores in the gas reservoir. Calculate the volume of the fractures in the gas reservoir based on the fracture area of ​​the gas reservoir. Based on the volume of the pores and the volume of the fractures in the gas reservoir, the gas reserves in the gas reservoir are calculated. The gas reserves in each gas reservoir are calculated using the process described above.

7. The tunnel gas detection method combining geological information and hyperspectral detection as described in claim 1, characterized in that, The gas escape rate within each gas reservoir is calculated as follows: ； ； Where v is the velocity of the gas relative to the spectrometer. This represents the reduction in wavelength within the band containing the absorption peak. The standard wavelength for the absorption peak band. At the speed of light, This refers to the observation wavelength in the band where the absorption peak is located.

8. A tunnel gas detection system combining geological information and hyperspectral detection, characterized in that, include: The acquisition module is used to acquire spectral image data and image data of the working face; The classification module is used to extract the spectral reflectance of each pixel in the spectral feature band based on the spectral image data, and compare the spectral reflectance with the reflectance in the standard gas spectral database and the standard mineral spectral database to determine the gas type and mineral type corresponding to each pixel. The analysis module is used to establish a gas storage layer based on the correspondence between gas types and mineral types at each pixel location; and to establish an efflux layer based on the fracture distribution of the gas storage layer obtained from the image data of the working face. Based on the correspondence between gas type and mineral type at each pixel location, a gas storage layer is established, specifically as follows: Determine whether the gas type at each pixel location corresponds to the gas produced by the mineral at that pixel. If so, determine that this area is a gas reservoir and label the gas type and reservoir area S. c All the gas storage layers constitute the gas storage layer. Create an escaping layer, specifically as follows: The image data of the working face is processed by grayscale and binarization to obtain the geometric shape, area and location distribution of the fractures, and then the fracture distribution of the gas storage layer is obtained. Determine whether the gas concentration at each fracture location in the gas storage layer shows a decreasing trend outward. If so, the corresponding fracture is an escape layer, and the location of the escape port and gas information are marked; all escape layers constitute an escape layer. The generation module is used to calculate the gas reserves and gas escape rate in each gas reservoir and generate a detection report.

Images