Method and system for detecting termite nest by contactless close-range laser infrared fusion detection

Abstract

The application belongs to the cross technical field of termite disaster prevention and control, infrared imaging technology, laser spectrum analysis, remote sensing and information processing, and specifically discloses a non-contact short-distance laser infrared fusion method and system for detecting termite nest, which comprises the following steps: performing infrared remote sensing scanning along the dam to obtain a dam remote sensing image; measuring the chemical substance concentration of the dam based on laser absorption spectrum technology; establishing a dam surface radiation energy model to calculate the heat flow field energy of the underground termite nest target and generate a thermal image area graph; comparing the thermal image area graph with the dam background heat flow field energy to preliminarily locate the termite nest area; and using the methane gas concentration information in the chemical substance concentration of the dam to generate a biological chemical substance concentration cloud chart to further locate the termite nest. The application can realize large-area dam termite nest detection.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of termite disaster prevention and control, infrared imaging technology, laser spectroscopy analysis, remote sensing and information processing, more specifically, relates to a non-contact short-distance laser infrared fusion termite nest detection method and system. BACKGROUND

[0002] Hydraulic embankments play a crucial role in flood control and disaster reduction. Embankments maintain the rational allocation and use of water resources, ensuring the safety and stability of agricultural irrigation, industrial water use, and domestic water supply. However, embankments are vulnerable to termite infestation, and termite activity poses a significant threat to the safety of infrastructure such as embankments and buildings. The formation of termite nests and channels can lead to structural hollowing, thereby weakening the load-bearing capacity of embankments and buildings. In order to prevent the spread of termite damage, it is of great significance to detect and locate termite nests in a timely and accurate manner.

[0003] Existing termite detection methods have serious technical limitations and cannot meet the needs of modern embankment termite control. Specifically, common termite nest detection methods include:

[0004] Manual visual inspection: This method relies on manual observation of termite activity signs (such as mud tubes and nests) on the surface of embankments or buildings. It is simple and does not require complex equipment. However, it can only detect surface termite activity and is difficult to find deep or internal nests. Manual visual inspection requires experienced operators, has low detection efficiency, and cannot achieve full coverage in large-scale embankment detection, which is prone to missed or false detections.

[0005] Sound detection: This method uses sound sensors to listen to the weak sound signals generated by termites when they move in embankments or wood. Although this method can be effective in specific environments (such as wooden structures), its accuracy is significantly affected by environmental noise. In addition, the sound signals generated by termite activity are weak and have limited sensitivity, making it difficult to effectively apply in large-scale structures such as embankments.

[0006] Microwave detection: This method uses microwaves to penetrate the surface of objects and detect changes in microwave reactions or dynamic images caused by termite activity. Microwave detection has a certain penetration ability and can detect internal activity. However, its penetration depth is limited, especially in thick soil layers or hard concrete structures, and the equipment cost is high and the operation is complex.

[0007] X-ray detection: This method uses X-ray imaging technology to detect termite nest damage to the internal structure of embankments or buildings. Although X-ray technology has good resolution and can image internal damage, its radiation can harm humans and the environment, making it difficult to apply in large areas. At the same time, the penetration depth of X-rays is limited in thick structures, and it does not have enough feasibility in actual embankment detection.

[0008] The above detection device and technology need to be in close contact with the embankment, and it is difficult to detect and locate termite nests for millions of kilometers of embankment all day long. SUMMARY

[0009] In view of the defects of the prior art, the purpose of the present application is to provide a non-contact near-distance laser infrared fusion detection method and system for termite nests, aiming to solve the problem of difficult detection of large-area embankment termite nests caused by the large environmental interference and limited detection depth of the existing termite nest detection technology.

[0010] To achieve the above-mentioned purpose, in a first aspect, the present application provides a non-contact near-distance laser infrared fusion detection method for termite nests, comprising the following steps:

[0011] Step one: perform infrared remote sensing scanning along the embankment to obtain an embankment remote sensing image; and measure the chemical substance concentration of the embankment based on laser absorption spectroscopy technology;

[0012] Step two: establish an embankment surface radiation energy model including the heat flow field energy of the underground termite nest target, the background heat flow field energy of the corresponding position of the underground termite nest target, the background heat flow field energy of the embankment, and the solar radiation energy received by the embankment, calculate the heat flow field energy of the underground termite nest target, and generate a thermal image area graph; wherein, the embankment surface radiation energy is obtained by using the infrared remote sensing image of the embankment surface, and the background heat flow field energy of the embankment and the background heat flow field energy of the corresponding position of the underground termite nest target are obtained based on the layered filtering method of different soil layer heat flow field energy; the solar radiation energy received by the embankment is calculated by the sum of the direct solar radiation and the scattered solar radiation;

[0013] Step three: compare the thermal image area graph with the background heat flow field energy of the embankment to preliminarily locate the termite nest area;

[0014] Step four: based on the termite nest area obtained in step three, use the methane gas concentration information in the chemical substance concentration of the embankment to generate a biological chemical substance concentration cloud map, and further locate the termite nest.

[0015] Further preferably, the expression of the embankment surface radiation energy model in step two is:

[0016]

[0017] Wherein, is the embankment surface radiation energy; is the background heat flow field energy of the embankment; is the heat flow field energy of the termite nest target in the embankment; is the solar radiation energy received by the embankment surface; is the background heat flow field energy of the corresponding position of the underground termite nest target.

[0018] Further preferably, the amount of direct solar radiation is the sum of direct radiation in all solar sectors, and the amount of solar scattered radiation is the sum of scattered radiation in the sky sectors.

[0019] Further preferably, the energy of the background heat flow field of the embankment with different thicknesses is:

[0020]

[0021] wherein, and are the cross-sectional area and the attenuation coefficient of the heat flow at a certain depth inside the embankment, respectively; and are the height coordinate of the embankment surface and the height coordinate at a certain depth from the embankment surface downward, respectively, by adjusting to realize the calculation of the energy of the background heat flow field of the embankment with different thicknesses;

[0022]

[0023] wherein, is the heat flow per unit area; is the volumetric heat capacity of the soil medium; is the thermal conductivity of the soil medium; and are the temperature field distribution of the embankment background and the temperature field distribution of the ant nest target inside the embankment, respectively; is the vertical temperature gradient.

[0024] Further preferably, in step three, when there is a region in the thermal image area map where the heat flow field is different from the energy of the background heat flow field of the embankment, and the different region corresponds to a heat flow field greater than the energy of the background heat flow field of the embankment, the different region is taken as the termite nest region.

[0025] In step four, if the methane gas concentration of the termite nest region obtained in step three is higher than the methane gas concentration of other regions of the thermal image area map, the region with high methane gas concentration is located as the termite nest.

[0026] In a second aspect, the present application provides a non-contact close-range laser infrared fusion detection termite nest system, comprising: an infrared imaging detector, a laser methane detector, an inertial navigation attitude positioner, and an information processor.

[0027] The infrared imaging detector is used for infrared remote sensing scanning along the embankment to obtain an embankment remote sensing image.

[0028] The laser methane detector is used for measuring the concentration of chemical substances in the embankment based on laser absorption spectroscopy technology.

[0029] The inertial navigation attitude positioner is used for tracking the position and attitude of the infrared imaging detector and / or the laser methane detector in real time through inertial navigation and attitude monitoring technology;

[0030] The information processor comprises a model construction module, an initial positioning module and a second positioning module;

[0031] The model construction module is used for establishing a dam surface radiation energy model comprising a heat flow field energy of the underground termite nest target, a background heat flow field energy of a corresponding position of the underground termite nest target, a dam background heat flow field energy and a solar radiation energy received by the dam, calculating the heat flow field energy of the underground termite nest target, and generating a thermal image area graph; wherein the dam surface radiation energy is obtained by using an infrared remote sensing image of the dam surface, and the dam background heat flow field energy and the background heat flow field energy of the corresponding position of the underground termite nest target are obtained based on a layered filtering method of different soil layer heat flow field energies; the solar radiation energy received by the dam is calculated by summing up the direct solar radiation and the scattered solar radiation;

[0032] The initial positioning module is used for comparing the thermal image area graph with the dam background heat flow field energy, and initially positioning the termite nest area;

[0033] The second positioning module is used for generating a biological chemical substance concentration cloud map based on the initially positioned termite nest area and using the methane gas concentration information in the dam chemical substance concentration, and further positioning the termite nest.

[0034] Further preferably, the dam surface radiation energy model expression in the model construction module is:

[0035]

[0036] wherein, is the dam surface radiation energy; is the dam background heat flow field energy; is the dam inner termite nest target heat flow field energy; is the solar radiation energy received by the dam surface; is the background heat flow field energy of the corresponding position of the underground termite nest target.

[0037] Further preferably, the direct solar radiation in the model construction module is the sum of the direct radiation in all solar sectors, and the scattered solar radiation is the sum of the scattered radiation in the sky sectors.

[0038] Further preferably, the dam background heat flow field energy of different thicknesses in the model construction module is:

[0039]

[0040] wherein, xyz is a Cartesian coordinate system; and are the cross-sectional area at a certain depth inside the dam and the attenuation coefficient of heat flow, respectively; and They are the height coordinates of the dam surface and the height coordinates of a certain depth from the dam surface. By adjusting Achieve calculation of background thermal flow field energy of dams with different thicknesses;

[0041]

[0042] in, is the heat flux per unit area; is the volumetric heat capacity of the soil medium; is the thermal conductivity of the soil medium; and They are the temperature field distribution of the dam background and the temperature field distribution of the ant nest target inside the dam; is the temperature gradient in the vertical direction.

[0043] Further preferably, the initial positioning module is used to determine whether the thermal flow field in the thermal image area map is the same as the energy of the dam background thermal flow field. When there is an area in the thermal image area map with a thermal flow field having different energies from the dam background thermal flow field, and the thermal flow field corresponding to the different area is greater than the energy of the dam background thermal flow field, the different area is regarded as a termite nest area.

[0044] The second positioning module is used to locate the area with high methane gas concentration as the termite nest if the methane gas concentration corresponding to the termite nest area obtained by the initial positioning module is higher than the methane gas concentration in other areas of the thermal image area map.

[0045] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the existing technologies:

[0046] This application provides a non-contact, close-range laser infrared fusion method for detecting termite nests. By analyzing the distribution of infrared radiation energy on the dam surface and its correlation with the thermal flow field inside the dam, a method for locating the termite nest area by extracting the thermal flow field energy of the ant nest is constructed. In this method, the resolution and accuracy of the termite nest signal can be significantly improved by layered filtering of the thermal flow field energy of different soil layers. In addition, combined with the compensation mechanism of solar radiation, it can effectively reduce the interference of environmental factors on the observation results, ensuring the stability and reliability of ant nest positioning. The above-mentioned non-destructive detection method based on infrared remote sensing technology provides technical support for daily inspections of embankment projects and termite damage monitoring.

[0047] This application provides a non-contact, close-range laser infrared fusion method for detecting termite nests. It scans and monitors the methane concentration on the surface of the dam and in the surrounding air in real time, and can accurately capture abnormal changes in methane concentration. By using the concentration distribution model and diffusion law, combined with the internal structural characteristics of the dam, the specific location of the methane release source can be inverted, thereby achieving accurate positioning of the termite nest.

[0048] The present application provides a non-contact, close-range laser-infrared fusion system for detecting termite nests. The system uses an infrared imaging detector to perform infrared remote sensing scanning along the embankment to obtain remote sensing images of the embankment. A thermal image area map is generated by constructing the thermal flow field energy of the underground ant nest target. This non-destructive detection method based on infrared remote sensing technology is used to detect termite nests. A laser methane detector, based on laser absorption spectroscopy technology, measures the concentration of chemical substances in the embankment, accurately capturing abnormal changes in methane concentration and achieving precise positioning of termite nests. The infrared imaging detector and laser methane detector described above are non-contact, close-range laser infrared detection methods that can detect termite nests in embankments over large areas.

[0049] The present application provides a non-contact, close-range laser infrared fusion method for detecting termite nests. Based on the differences in the structure, material, temperature and other properties of ant nests and their surrounding environment, and according to the principles of geophysics, thermophysics, geochemistry and spectroscopy, the existence of ant nests that are different from the dam environment causes changes in the distribution of the thermal field / light field / chemical field of the environmental background field in which they are located. Through the combination of multiple perceptions and physical and chemical characteristics, the present application can efficiently, accurately and non-destructively achieve precise positioning of termite nests in dams and other key areas, providing strong technical support for termite prevention and control work. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a schematic diagram of termite nest detection provided by an embodiment of the present application;

[0051] Figure 2 This is a flowchart of dam termite nest detection provided by an embodiment of the present application;

[0052] Figure 3 is a schematic diagram of solar radiation received by the dam surface provided in an embodiment of the present application;

[0053] Figure 4 Schematic diagram of the distribution of solar scattered radiation received at an observation point provided in an embodiment of the present application; black indicates invisible;

[0054] Figure 5 is the absorption spectrum of different gases provided in the embodiments of the present application;

[0055] Figure 6Schematic diagram of air mass concentration measured by the detector provided in an embodiment of the present application;

[0056] Figure 7 This is a termite nest detection and positioning system based on hydraulic engineering maps provided in an embodiment of the present application;

[0057] Figure 8 This is a visible light image of a termite nest in a certain area provided by an embodiment of the present application;

[0058] Figure 9 This embodiment of the present application provides Figure 8 infrared images of termite nests in the area;

[0059] Figure 10 This is a visible light image of a termite nest in another region provided by an embodiment of the present application;

[0060] Figure 11 This embodiment of the present application provides Figure 10 Infrared image of termite nest area in the region

[0061] Figure 12 This embodiment of the present application provides Figure 8 Infrared image of methane concentration measured in a heat map area in the region. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0063] The term "and / or" as used herein describes an association between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. The symbol " / " as used herein indicates that the related objects are in an "or" relationship, for example, A / B means either A or B.

[0064] The terms "first" and "second" and the like in the description and claims herein are used to distinguish different objects rather than to describe a specific order of the objects.

[0065] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0066] In the description of the embodiments of the present application, unless otherwise specified, “plurality” means two or more.

[0067] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0068] This application provides a non-contact, close-range laser infrared fusion method for detecting termite nests. The specific principle is: by analyzing the thermal environment characteristics of termite nests and the heat differences generated by termite metabolic activities, it is found that soil and rock in nature, under the influence of the environment, have randomly distributed capillary clusters from bottom to top, allowing for the exchange of matter and energy between the underground and the ground. Termite colonies are biological communities and the spaces where they inhabit their nests. They produce metabolic substances and individual biological death processes, generating related substances and heat, and engaging in material and energy exchange and heat transfer with the embankments they inhabit. Therefore, thermal and biomass information of termite nests can be located through close-range remote sensing.

[0069] The internal temperature of ant nests and ant paths is higher than that of the surrounding environment due to the biological activities of termites. Due to the capillary plexus phenomenon, the heat generated by the termite nests in the dam and the chemical substances generated by the termite activities can be transferred to the surface of the dam through the capillary plexus, thus forming a "thermal image" area that is different from the "dam area without termite nests" and an area with high "biological substances" such as methane and formic acid. The "thermal image area" and "area with high concentration of biochemical substances" are the physical and chemical basis of this application, such as Figure 1 As shown;

[0070] The following is a detailed description of the non-contact close-range laser infrared fusion method for detecting termite nests provided by this application. Figure 2 As shown, the specific steps include:

[0071] Step S1: Perform infrared remote sensing scanning along the embankment to obtain remote sensing images of the embankment; and use laser absorption spectroscopy technology to measure the concentration of chemical substances in the embankment;

[0072] Step S2: Analyze the thermal flow field of the dam without considering the termite nest;

[0073] As the heat inside the dam is conducted in the soil layer, a directional heat flow will be formed. Similar to the penetrating power of X-rays, the heat flow can "penetrate" from the bottom of the dam to the surface of the dam, thus forming a vector heat flow field. When the heat flow is transmitted in different soil layers, there will be different degrees of diffusion and attenuation due to differences in geological conditions, and the heat flow field is higher than the temperature field inside the dam itself. The infrared radiation of the dam surface obtained from the infrared remote sensing image can be regarded as the superposition of the heat flow fields of each layer of the dam. The DN value of the infrared radiation of the dam surface obtained from the infrared remote sensing image can be obtained by simulating the energy of the heat flow fields of each layer of the dam.

[0074] Under ideal conditions, the heat flux per unit area is calculated as follows:

[0075]

[0076] in, is the volumetric heat capacity of the soil medium; is the thermal conductivity of the soil medium; and They are the temperature field distribution of the dam background and the temperature field distribution of the ant nest target inside the dam; The temperature gradient in the vertical direction can be calculated using the differential approximation. The temperature gradient needs to be calculated using the temperature field.

[0077] The thermal background field distribution inside the dam is roughly the same. Similarly, based on the distribution of soil layers, the thermal flow field can be assumed to be the same. The thermal flow field energy of each layer is calculated. The thermal flow field energy of dams of different thicknesses is filtered out in sequence using the real infrared radiation of the dam surface obtained through infrared remote sensing images. This can effectively protect the target information and obtain a more accurate target disturbance signal distribution.

[0078] Step S3: dam ant nest temperature field / thermal flow field analysis method;

[0079] Due to the biological activities of termites, the internal temperature of ant nests and ant paths is higher than that of the surrounding environment and the inside of the dam. Due to the capillary phenomenon, the heat generated by the termite nests and the chemicals generated by the termite activities can be transferred to the surface of the dam through the capillary plexus.

[0080] Since the heat transfer law of the underground ant nest target conforms to the physical mathematical model of heat conduction, the temperature field distribution of the dam and the termite nest can be obtained according to the heat transfer theorem and law, and then the superposition of the heat flow field distribution of the two can be calculated; since the dam is a three-dimensional structure, the distribution formula of the energy field should also be expressed in three-dimensional form. Assuming that at a certain moment Dam surface The radiation energy at According to the law of conservation of energy, the value of this radiation energy can be calculated from the thermal flow field energy of the underground ant nest target, the background thermal flow field energy of the dam, the radiation energy exchanged between them and the environment, and the received solar radiation energy:

[0081]

[0082] in, Radiates energy to the dam surface; is the background thermal flow field energy of the dam; is the target thermal flow field energy of the ant nest inside the dam; is the radiation energy at the interface between the dam and the air; the solar radiation energy received by the dam surface; the background heat flow field energy of the corresponding position of the underground ant nest target (such as the heat flow field generated by the local dam background without the ant nest);

[0083] In a real environment, the radiation energy of the dam surface in contact with the air is very small, and can be basically ignored compared with the heat flow field energy of the dam and the ant nest. In this application, only the relationship among the heat flow field energy of the dam background, the heat flow field energy of the underground ant nest target and the solar radiation energy received by the dam surface is considered;

[0084] The solar radiation received by the ground includes direct radiation, scattered radiation and reflected radiation, as shown in FIG. 1; Figure 3

[0085] The total amount of solar radiation is obtained by adding the amount of direct solar radiation and the amount of scattered radiation;

[0086]

[0087] wherein, is the total amount of solar radiation; and are the total amount of direct radiation and the total amount of scattered radiation, respectively;

[0088] The amount of direct solar radiation is the sum of the direct radiation in all solar sectors, and the amount of scattered radiation is the sum of the scattered radiation in all sky sectors;

[0089]

[0090]

[0091] wherein, and are the amounts of direct radiation and scattered radiation, respectively, with the centroid located at the zenith angle and the azimuth angle .

[0092] As can be seen from the above formula, the heat flow field energy generated by the underground ant nest, the heat flow field energy of the dam background and the solar radiation energy are superimposed to form the observable infrared radiation energy distribution of the dam surface. By deforming the above formula, the calculation formula of the heat flow field energy of the underground ant nest target can be obtained, which is as follows:

[0093]

[0094] In the iterative calculation process, the energy contained in the dam background of different thicknesses needs to be calculated in combination with the heat flow field energy distribution of the dam background, and the specific formula is as follows:

[0095] ​

[0096] wherein, and are the cross-sectional area and the attenuation coefficient of the heat flow at a certain depth inside the dam, respectively; and are the height coordinate of the dam surface and the height coordinate at a certain depth from the dam surface, respectively, by adjusting the heat flow field energy contained in the background of the dam of different thicknesses can be realized; by comparing the thermal image area graph with the heat flow field energy of the dam background, the termite nest can be initially positioned; more specifically, it is judged whether the heat flow field in the thermal image area graph is the same as the heat flow field energy of the dam background; when there is a region in the thermal image area graph where the heat flow field is different from the heat flow field energy of the dam background, and the different region corresponds to the thermal image area heat flow field greater than the heat flow field energy of the dam background, the different region is taken as the termite nest region;

[0097] In summary, the present application constructs a complete calculation process from termite nest heat flow field energy extraction to target positioning by analyzing the correlation between the infrared radiation energy distribution of the dam surface and the heat flow field inside the dam; by layering and filtering the heat flow field energy of different soil layers, the resolution and accuracy of the target signal can be significantly improved. In addition, combined with the compensation mechanism of solar radiation, the present application can effectively reduce the interference of environmental factors on the observation results, ensuring the stability and reliability of the termite nest positioning. This non-destructive detection method based on infrared remote sensing technology provides technical support for the daily patrol of the dam and the monitoring of termite damage.

[0098] Step S4: dam methane concentration distribution field analysis method;

[0099] Termites are group organisms living in a semi-closed nest system, self-contained in the dark nest system; termites feed on a large amount of cellulose, but only termites themselves cannot complete the whole process of dissolving cellulose, relying on the assistance of a large number of microorganisms in their intestines; higher ants such as soil termites lack symbiotic protozoa, rely on their own secreted cellulase to decompose food, and can cultivate bacterial garden for young termites to eat; termites intestinal bacteria produce methane when decomposing organic matter, and are one of the main producers of methane in nature;

[0100] The termite nest produces a large amount of methane in the process of decomposing organic matter due to its unique ecological system; the microorganisms in the termite intestine, especially the methane-producing bacteria, release methane gas when decomposing organic matter such as cellulose; these methane gas will diffuse through the nest system to the dam surface and the surrounding air, forming a local methane concentration anomaly area; based on this characteristic, the present application proposes a method for positioning the dam termite nest using methane laser technology.

[0101] Methane laser sensor is based on laser absorption spectroscopy technology. Its core is to use the obvious absorption characteristics of methane gas molecules under infrared laser of specific wavelength (such as 1.65μm). Laser detection technology can accurately emit single wavelength light, thereby effectively eliminating the interference of ambient gas and truly achieving single wavelength scanning. Figure 5 The figure shows an absorption spectrum diagram that displays the absorption characteristics of different gases (such as water vapor, methane, carbon dioxide, and ammonia) at specific wavelengths. Each gas has a specific absorption wavelength range and exhibits significant absorption characteristics within this wavelength range. Figure 5 The characteristic absorption bands of methane and others (absorption peak near 1.65 μm) are marked with boxes;

[0102] When laser light passes through an area with methane concentration, its light intensity is attenuated by methane absorption. By measuring the attenuation, the methane gas concentration distribution can be accurately calculated. The concentration detected by the laser methane sensor is the cumulative concentration of gas along the effective laser transmission path. Generally, reflective linear beam detector systems do not distinguish between the gas concentration within a local area on the working light path. In other words, the effect of a small area of ​​high concentration gas is the same as that of a large area of ​​low concentration gas. The sensor unit is the average gas concentration in ppm.m or %LEL.m. Figure 6 The test results of describing the 1m 100%LEL air mass, the 2m 50%LEL air mass and the 4m 25%LEL air mass are equal;

[0103] 100%LEL*1M=50%LEL*2M=25%LEL*4M

[0104] Methane laser technology features high sensitivity, high resolution, and long-distance detection. By using methane laser sensors, the methane concentration on the dam surface and in the surrounding air is scanned and monitored in real time, accurately capturing abnormal changes in methane concentration. Using concentration distribution models and diffusion laws, combined with the internal structural characteristics of the dam, the specific location of the methane release source can be inverted, thereby achieving precise positioning of termite nests.

[0105] More specifically, if the methane gas concentration corresponding to the termite nest area obtained by the initial positioning module is higher than the methane gas concentration in other areas of the thermal image area map, the area with high methane gas concentration is positioned as the termite nest.

[0106] Second, as Figure 7 As shown, the present application provides a non-contact close-range laser infrared fusion method for detecting termite nests, specifically comprising:

[0107] Infrared imaging detectors are used to capture and analyze thermal signals in the target area. They use infrared imaging technology to detect the temperature difference between the heat generated by the termite nest and the surrounding environment, thereby identifying and locating the nest.

[0108] Laser methane detector, for detecting the possible presence of methane gas in termite nests based on laser absorption spectroscopy technology; since methane is often related to the biological activity of termite nests, the laser methane detector can further confirm the location of the nest and provide gas concentration information;

[0109] Inertial navigation attitude positioner, for tracking the position and attitude of the detector in real time through inertial navigation and attitude monitoring technology, ensuring high-precision positioning and stability of the system in complex environments;

[0110] Information processor, responsible for collecting data from various detectors and performing comprehensive analysis and processing, through advanced algorithms, the information processor can quickly compare infrared spectra and gas detection results, accurately locate termite nests, and provide real-time feedback and alarm information;

[0111] The structure, material and temperature of the termite nest are different from the surrounding environment, according to the principles of geophysics, thermophysics, geochemistry and spectroscopy, the existence of termite nests different from the dam environment causes changes in the thermal field / light field / chemical field distribution of the environmental background field; this application can efficiently, accurately and non-destructively locate termite nests in dams and other key areas, providing strong technical support for termite control work.

[0112] Example 1

[0113] Figure 8 The visible light image of the termite nest taken in a certain area, Figure 9 The infrared image of the area; Figure 8 The red oval area in the middle is the accurate location of the termite nest in the area; Figure 9 The red oval area in the middle corresponds to it; observing the infrared image of the termite nest, it can be seen that the thermal signal of the termite nest area is higher than that of the surrounding area, and the methane concentration measured at this point is 258 ppm, 538 ppm, 829 ppm, 569 ppm, 1123 ppm and 1266 ppm; from this, it can be seen that there is enough methane concentration signal, and there is enough thermal signal, and there is a high possibility of a termite nest below.

[0114] Example 2

[0115] Figure 10 The visible light image of another area of non-termite nest, Figure 11 The infrared image of the area; Figure 11The inner red frame is a suspected area of an anthill, and the methane concentration detected at this area is 630 ppm, 288 ppm, 367 ppm, 510 ppm, 366 ppm, 586 ppm, 1069 ppm, 827 ppm and 745 ppm. However, no anthill was found after the area was dug, so the position of the anthill cannot be determined only by the methane concentration. As can be seen from the above, in the area with sufficient methane concentration signal but without sufficient heat signal, there is no anthill below.

[0116] Example 3

[0117] Figure 12 For Figure 7 The area is a vegetation area in the anthill-free area of the region, and the heat signal of this area is high, but the methane test result is 0 ppm. Therefore, the suspected anthill area cannot be confirmed only by the infrared heat information.

[0118] In summary, in the area with sufficient methane concentration signal and sufficient heat signal, there is likely to be an anthill below; in the area with sufficient methane concentration signal but without sufficient heat signal, there is no anthill below; and in the area with sufficient heat signal but without sufficient methane concentration signal.

[0119] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A non-contact close-range laser infrared fusion method for detecting termite nests, characterized in that: The following steps are involved: Step 1: Conduct infrared remote sensing scanning along the embankment to obtain remote sensing images of the embankment; and, based on laser absorption spectroscopy, measure the concentration of chemical substances in the embankment; Step 2: Establish a dam surface radiation energy model that includes the heat flow field energy of the underground ant nest target, the background heat flow field energy at the location corresponding to the underground ant nest target, the dam background heat flow field energy, and the solar radiation energy received by the dam. Calculate the heat flow field energy of the underground ant nest target and generate a thermal image area map. The dam surface radiation energy is obtained using infrared remote sensing images of the dam surface. Simultaneously, a layered filtering method based on the heat flow field energy of different soil layers is used to obtain the heat of the dam background heat flow field and the background heat flow field energy at the location corresponding to the underground ant nest target. The solar radiation energy received by the dam is obtained by calculating the sum of direct solar radiation and scattered solar radiation. Step 3: Compare the thermal image area map with the background thermal flow field energy of the dam to initially locate the termite nest area; Step 4: Based on the termite nest area obtained in step 3, the methane gas concentration information in the dam chemical concentration is used to generate a biochemical substance concentration cloud map to further locate the termite nest.

2. The non-contact close-range laser infrared fusion method for detecting termite nests according to claim 1, characterized in that: The model expression of the dam surface radiation energy in step 2 is: in, Radiates energy to the dam surface; is the background thermal flow field energy of the dam; is the target thermal flow field energy of the ant nest inside the dam; is the solar radiation energy received by the dam surface; is the background thermal flow field energy at the corresponding position of the underground ant nest target.

3. The non-contact close-range laser infrared fusion method for detecting termite nests according to claim 2, characterized in that: The direct solar radiation is the sum of the direct radiation in all sun map sectors, and the diffuse solar radiation is the sum of the diffuse radiation in the sky map sectors.

4. The non-contact close-range laser infrared fusion method for detecting termite nests according to claim 1 or 2, characterized in that: The background thermal flow field energy of dams with different thicknesses is: in, xyz is the Cartesian coordinate system; and are the cross-sectional area at a certain depth inside the dam and the attenuation coefficient of heat flow, respectively; and They are the height coordinates of the dam surface and the height coordinates of a certain depth from the dam surface. By adjusting Achieve calculation of background thermal flow field energy of dams with different thicknesses; in, is the heat flux per unit area; is the volumetric heat capacity of the soil medium; is the thermal conductivity of the soil medium; and They are the temperature field distribution of the dam background and the temperature field distribution of the ant nest target inside the dam; is the temperature gradient in the vertical direction.

5. The non-contact close-range laser infrared fusion method for detecting termite nests according to claim 1, characterized in that: In step 3, when there is an area in the thermal image area map where the thermal flow field has different energy from the dam background thermal flow field, and the thermal flow field corresponding to the different area in the thermal image area is greater than the energy of the dam background thermal flow field, the different area is regarded as a termite nest area; In step 4, if the methane gas concentration corresponding to the termite nest area obtained in step 3 is higher than the methane gas concentration in other areas of the thermal image area map, the area with high methane gas concentration is located as the termite nest.

6. A non-contact close-range laser infrared fusion termite nest detection system, characterized in that: include: Infrared imaging detectors, laser methane detectors, inertial navigation attitude locators and information processors; The infrared imaging detector is used to conduct infrared remote sensing scanning along the embankment to obtain remote sensing images of the embankment; Laser methane detectors are used to measure the concentration of chemicals in dams based on laser absorption spectroscopy; The inertial navigation attitude locator is used to track the position and attitude of the infrared imaging detector and / or laser methane detector in real time through inertial navigation and attitude monitoring technology; The information processor includes a model building module, an initial positioning module and a second positioning module; The model building module is used to establish a dam surface radiation energy model that includes the heat flow field energy of the underground ant nest target, the background heat flow field energy at the corresponding position of the underground ant nest target, the dam background heat flow field energy, and the solar radiation energy received by the dam, calculate the heat flow field energy of the underground ant nest target, and generate a thermal image area map. The infrared remote sensing image of the dam surface is used to obtain the dam surface radiation energy. At the same time, the layered filtering method of the heat flow field energy of different soil layers is used to obtain the heat of the dam background heat flow field and the background heat flow field energy at the corresponding position of the underground ant nest target. The solar radiation energy received by the dam is calculated by summing the direct solar radiation and the scattered solar radiation. The initial positioning module is used to compare the thermal image area map with the background thermal flow field energy of the dam to perform initial positioning of the termite nest area; The second positioning module is used to generate a biochemical substance concentration cloud map based on the initially located termite nest area and utilize the methane gas concentration information in the dam chemical substance concentration to further locate the termite nest.

7. The non-contact close-range laser infrared fusion termite nest detection system according to claim 6, characterized in that: The model expression of the dam surface radiation energy in the model building module is: in, Radiates energy to the dam surface; is the background thermal flow field energy of the dam; is the target thermal flow field energy of the ant nest inside the dam; is the solar radiation energy received by the dam surface; is the background thermal flow field energy at the corresponding position of the underground ant nest target.

8. The non-contact close-range laser infrared fusion termite nest detection system according to claim 7 is characterized in that: In the model building module, the direct solar radiation is the sum of the direct radiation in all sun map sectors, and the diffuse solar radiation is the sum of the diffuse radiation in the sky map sectors.

9. The non-contact close-range laser infrared fusion termite nest detection system according to claim 6 or 7, characterized in that: The background thermal flow field energy of dams of different thicknesses in the model building module is: in, xyz is the Cartesian coordinate system; and are the cross-sectional area at a certain depth inside the dam and the attenuation coefficient of heat flow, respectively; and They are the height coordinates of the dam surface and the height coordinates of a certain depth from the dam surface. By adjusting Achieve calculation of background thermal flow field energy of dams with different thicknesses; in, is the heat flux per unit area; is the volumetric heat capacity of the soil medium; is the thermal conductivity of the soil medium; and They are the temperature field distribution of the dam background and the temperature field distribution of the ant nest target inside the dam; is the temperature gradient in the vertical direction.

10. The non-contact close-range laser infrared fusion termite nest detection system according to claim 6, characterized in that: The initial positioning module is used to determine whether the thermal flow field in the thermal image area map is the same as the dam background thermal flow field energy. If there are areas in the thermal image area map where the thermal flow field energy is different from the dam background thermal flow field energy, and the thermal flow field corresponding to the different areas in the thermal image area is greater than the dam background thermal field energy, the different areas are regarded as termite nest areas. The second positioning module is used to locate the area with high methane gas concentration as the termite nest if the methane gas concentration corresponding to the termite nest area obtained by the initial positioning module is higher than the methane gas concentration in other areas of the thermal image area map.

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