Method and system for detecting termite nest through non-contact close-range laser and infrared fusion

Abstract

The invention belongs to the cross technical field of termite disaster prevention and control, infrared imaging technology, laser spectrum analysis, remote sensing and information processing, and particularly discloses a non-contact close-range laser infrared fusion termite nest detection method and system, and the method comprises the steps: carrying out the infrared remote sensing scanning along a dam, and obtaining a dam remote sensing image; measuring the chemical substance concentration of the dam based on a laser absorption spectrum technology; establishing a dam surface radiation energy model, calculating heat flow field energy of the underground ant nest target, and generating a thermal image area map; comparing the thermal image area map with dam background heat flow field energy, and carrying out primary positioning on a termite nest area; and generating a biochemical substance concentration cloud picture by using methane gas concentration information in the chemical substance concentration of the dam, and further positioning the termite nest. According to the invention, large-area embankment termite nest detection can be realized.

Description

Technical Field

[0001] The present 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 more specifically, to a method and system for non-contact close-range laser infrared fusion detection of termite nests. Background Art

[0002] Hydraulic levees play a vital role in flood prevention and disaster reduction. Levees maintain the rational dispatch and use of water resources, ensuring the safety and stability of agricultural irrigation, industrial water and domestic water supply. However, the interior of the levees is vulnerable to termite infestation. The activities of termites pose a major threat to the safety of infrastructure such as levees and buildings. The formation of their nests and channels will lead to structural hollowing, thereby weakening the bearing capacity of levees and buildings. In order to prevent the spread of termite damage, it is extremely important to detect and locate termite nests in a timely and accurate manner.

[0003] Existing termite detection methods have serious technical limitations and are difficult to meet the needs of modern embankment termite control. Specifically, common termite nest detection methods are: Manual visual inspection: It relies on manual observation of termite activity signs (such as mud tubes and nests) on the surface of levees or buildings. This method is simple and does not require complex equipment. However, it can only detect termite activity on the surface 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 levee inspections, and is very easy to miss or misdetect.

[0004] Sound detection: Sound sensors are used to monitor the weak sound signals produced by termites when they move in embankments or wood. Although this method can be effective in certain environments (such as wooden structures), its accuracy is significantly affected by environmental noise. In addition, the sound signals of termite activity are weak and have limited sensitivity, making it difficult to effectively apply them in large-scale structures such as embankments.

[0005] Microwave detection: Microwaves penetrate the surface of objects to detect changes in microwave reactions or dynamic images generated by termite activity. Microwave detection has a certain penetrating ability and can detect activities inside objects. However, its penetration depth is limited, especially in thick soil layers or hard concrete structures, and the effect is not good. In addition, the equipment cost is high and the operation is complicated.

[0006] X-ray detection: X-ray imaging technology is used to detect damage to the internal structure of levees or buildings caused by termite nests. Although X-ray technology has good resolution and can image and display subtle internal damage, its rays may be harmful to the human body and the environment, making it difficult to apply on a large scale. At the same time, the penetration depth of X-rays is limited in thicker structures, which is not feasible enough in actual levee detection.

[0007] All of the above detection equipment and technologies require close contact with the levee, making it difficult to conduct round-the-clock detection and location of termite nests on millions of kilometers of levees. Summary of the invention

[0008] In view of the defects of the prior art, the purpose of this application is to provide a method and system for detecting termite nests by non-contact close-range laser infrared fusion, aiming to solve the problem that the existing termite nest detection technology is greatly affected by environmental interference and has limited detection depth, resulting in difficulty in detecting termite nests in large areas of embankments.

[0009] To achieve the above objectives, in a first aspect, the present application provides a method for detecting termite nests by non-contact close-range laser infrared fusion, comprising the following steps: Step 1: Conduct infrared remote sensing scanning along the dam to obtain remote sensing images of the dam; and measure the concentration of chemical substances in the dam based on laser absorption spectroscopy technology; Step 2: Establish a dam surface radiation energy model including 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; wherein, the infrared remote sensing image of the dam surface is used to obtain the dam surface radiation energy, and at the same time, the dam background heat flow field heat and the background heat flow field energy at the corresponding position of the underground ant nest target are obtained based on the layered filtering method of the heat flow field energy of different soil layers; the solar radiation energy received by the dam is calculated by the sum of the direct solar radiation and the scattered solar radiation; Step 3: Compare the thermal image area map with the dam background thermal flow field energy 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.

[0010] Further preferably, the model expression of the dam surface radiation energy in step 2 is:

[0011] in, Radiate energy to the surface of the dam; is the background thermal flow field energy of the dam; It 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.

[0012] Further preferably, 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. Further preferably, the background thermal flow field energy of dams of different thicknesses is:

[0013] in, 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 at a certain depth from the dam surface. Realize the calculation of the background thermal flow field energy of dams with different thicknesses;

[0014] 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.

[0015] Further preferably, in step 3, when there are regions in the thermal image region map with different thermal flow field energies from the dam background thermal flow field, and the thermal flow field corresponding to the thermal image region of the different regions is greater than the thermal flow field energy of the dam background, the different regions are regarded as termite nest regions; 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.

[0016] In a second aspect, the present application provides a non-contact close-range laser infrared fusion detection system for termite nests, including: an infrared imaging detector, a laser methane detector, an inertial navigation attitude locator, and an information processor; 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 including 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; wherein, the infrared remote sensing image of the dam surface is used to obtain the dam surface radiation energy, and at the same time, the dam background heat flow field heat and the background heat flow field energy at the corresponding position of the underground ant nest target are obtained based on the layered filtering method of the heat flow field energy of different soil layers; the solar radiation energy received by the dam is calculated by the sum of 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 initially locate 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.

[0017] Further preferably, the model expression of the dam surface radiation energy in the model building module is:

[0018] in, Radiate energy to the surface of the dam; is the background thermal flow field energy of the dam; It 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.

[0019] Further preferably, the direct solar radiation in the model building module is the sum of the direct radiation in all sun map sectors, and the scattered solar radiation is the sum of the scattered radiation in the sky map sectors. Further preferably, the background thermal flow field energy of dams of different thicknesses in the model building module is:

[0020] 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 at a certain depth from the dam surface. Realize the calculation of the background thermal flow field energy of dams with different thicknesses;

[0021] 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.

[0022] 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 thermal flow field energy of the dam background. When there are areas in the thermal image area map where the thermal flow field has different energies from the thermal flow field energy of the dam background, and the thermal flow field corresponding to the thermal image area of ​​the different areas is greater than the thermal flow field energy of the dam background, 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.

[0023] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art: The present application provides a non-contact close-range laser infrared fusion method for detecting termite nests. By analyzing the infrared radiation energy distribution on the surface of the dam 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.

[0024] The present application provides a non-contact close-range laser infrared fusion method for detecting termite nests, which 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.

[0025] The present application provides a non-contact close-range laser infrared fusion detection system for termite nests, wherein an infrared imaging detector is used 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; a non-destructive detection method based on infrared remote sensing technology is used to detect termite nests, and a laser methane detector is used based on laser absorption spectroscopy technology to measure the concentration of chemical substances in the embankment, which can accurately capture abnormal changes in methane concentration and achieve accurate positioning of termite nests. The above-mentioned infrared imaging detector and laser methane detector belong to non-contact close-range laser infrared detection, which can realize large-area embankment termite nest detection.

[0026] The present application provides a method for detecting termite nests by non-contact close-range laser infrared fusion. The method is based on the differences in the structure, material, temperature and other properties of ant nests and their surrounding environment. 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 thermal fields / light fields / chemical fields of the background field of the environment in which they are located. The present application combines multiple perceptions and physical and chemical characteristics to efficiently, accurately and non-destructively locate termite nests in dams and other key areas, providing strong technical support for termite prevention and control. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of termite nest detection provided by an embodiment of the present application; Figure 2 is a flow chart of dam termite nest detection provided by an embodiment of the present application; Figure 3 is a schematic diagram of solar radiation received on the surface of a dam provided by an embodiment of the present application; Figure 4 is a schematic diagram of the distribution of solar scattered radiation received at the observation point provided in an embodiment of the present application; wherein black indicates invisible; Figure 5 is an absorption spectrum diagram of different gases provided in the embodiments of the present application; Figure 6 is a schematic diagram of air mass concentration measured by the detector provided in an embodiment of the present application; Figure 7 It is a termite nest detection and positioning system based on hydraulic engineering atlas provided in the embodiment of the present application; Figure 8 It is a visible light image of a termite nest in a certain area provided in an embodiment of the present application; Fig. 9 The embodiment of this application provides Figure 8 infrared images of termite nests in the area; Fig.10 It is a visible light image of a termite nest in another region provided in an embodiment of the present application; Fig.11 The embodiment of this application provides Fig.10 Infrared image of termite nest area Fig.12 The embodiment of this application provides Figure 8 Infrared image of methane concentration measured in a heat map area in the region. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0029] The term "and / or" in this article is a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The symbol " / " in this article indicates that the associated objects are in an or relationship, for example, A / B means A or B.

[0030] The terms “first”, “second” and the like in the specification and claims herein are used to distinguish different objects rather than to describe a specific order of the objects.

[0031] In the embodiments of the present 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 the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0032] In the description of the embodiments of the present application, unless otherwise specified, “plurality” means two or more than two.

[0033] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0034] The present 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, the soil and rocks in nature have randomly distributed capillary clusters from bottom to top under the influence of the environment, so that there is material and energy exchange between the underground and the ground. Termite colonies are biological groups and their nests. The space where they live will produce metabolic substances and individual biological death processes, generate related substances and heat, and exchange substances and energy and transfer heat with the embankments where they live. Therefore, the thermal information and biomass information of termite nests can be located through close-range remote sensing detection.

[0035] The internal temperature of ant nests and ant roads is higher than that of the surrounding environment due to the biological activities of termites. Due to the capillary 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; The following is a detailed description of the non-contact close-range laser infrared fusion method for detecting termite nests provided by the present application. Figure 2 As shown, the specific steps include: Step S1: perform infrared remote sensing scanning along the dam to obtain remote sensing images of the dam; and use laser absorption spectroscopy technology to measure the concentration of chemical substances in the dam; Step S2: Analyze the thermal flow field of the dam without considering the termite nest; 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 on 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 on 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.

[0036] Under ideal conditions, the heat flow per unit area is calculated as follows:

[0037] 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; is the temperature gradient in the vertical direction, which can be calculated using differential approximation; the temperature gradient needs to be calculated using the temperature field; The distribution of the thermal background field in the dam is roughly the same. Similarly, according to the distribution of soil layers, the thermal flow field can be considered to be the same. The thermal flow field energy of each layer is calculated, and the thermal flow field energy of dams of different thicknesses is filtered out in turn 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. Step S3: dam ant nest temperature field / thermal flow field analysis method; Ant nests and ant roads Due to the biological activities of termites, the internal temperature is higher than the surrounding environment and the inside of the dam. Due to the capillary 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 clusters. 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 time 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:

[0038] in, Radiate energy to the surface of the dam; is the background thermal flow field energy of the dam; It is the target thermal flow field energy of the ant nest inside the dam; is the radiation energy at the contact surface between the dam and the air; is the solar radiation energy received by the dam surface; The background thermal flow field energy at the location corresponding to the underground ant nest target (such as the thermal flow field generated by the background of a local dam where no ant nest exists); In a real environment, the radiation energy of the contact surface between the dam and the air is very small, which can be basically ignored compared with the thermal flow field energy of the dam and the ant nest. In this application, only the relationship between the thermal flow field energy of the dam background, the thermal flow field energy of the underground ant nest target and the solar radiation energy received by the dam surface is considered; The solar radiation received by the earth's surface includes direct radiation, scattered radiation and reflected radiation, such as Figure 3 As shown; The total solar radiation is obtained by adding the direct solar radiation and the diffuse radiation;

[0039] in, is the total solar radiation; and are the total direct radiation and the total diffuse radiation respectively; Direct solar radiation is the sum of direct radiation in all sun map sectors, and diffuse radiation is the sum of diffuse radiation in all sky map sectors;

[0040]

[0041] in, and The centroid is located at the zenith angle and the azimuth is of direct and diffuse radiation.

[0042] From the above formula, we can know that the thermal flow field energy generated by the underground ant nest, the thermal flow field energy of the dam background and the solar radiation energy are superimposed to form the observable infrared radiation energy distribution on the dam surface; by transforming the above formula, we can get the calculation formula of the thermal flow field energy of the underground ant nest target, which is as follows:

[0043] In the iterative calculation process, it is necessary to combine the energy distribution of the dam background thermal flow field to calculate the energy contained in the dam background of different thicknesses. The specific formula is as follows:

[0044] in, 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 at a certain depth from the dam surface. The thermal flow field energy contained in the dam background of different thicknesses can be calculated; by comparing the thermal image area map with the thermal flow field energy of the dam background, the termite nest can be initially located; more specifically, it is determined whether the thermal flow field in the thermal image area map is the same as the thermal flow field energy of the dam background. When there are areas in the thermal image area map where the thermal flow field has different energy from the thermal flow field of the dam background, and the thermal flow field corresponding to the thermal image area of ​​the different areas is greater than the thermal flow field energy of the dam background, the different areas are regarded as termite nest areas; In summary, this application constructs a complete calculation process from ant nest thermal flow field energy extraction to target positioning by analyzing the infrared radiation energy distribution on the dam surface and its correlation with the thermal flow field inside the dam; by layered filtering of thermal flow field energy in 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, this application can effectively reduce the interference of environmental factors on the observation results and ensure the stability and reliability of ant nest positioning. This non-destructive detection method based on infrared remote sensing technology provides technical support for daily inspections of embankment projects and monitoring of termite damage.

[0045] Step S4: dike methane concentration distribution field analysis method; Termites are colonies that live in semi-enclosed nest systems and form a self-contained entity in dark nest systems. Although termites eat a large amount of cellulose, they cannot dissolve the cellulose by themselves, and rely on the assistance of a large number of microorganisms in their intestines. Higher ants such as earth termites lack symbiotic protozoa, and rely on their own secreted cellulase to decompose food, and can cultivate fungus beds for young ants to eat. Termite intestinal bacteria produce methane when decomposing organic matter, and are one of the main producers of methane in nature. Due to their unique ecosystem, termite nests produce a large amount of methane in the process of decomposing organic matter. The microorganisms in the termite intestines, especially methane-producing bacteria, release methane gas when decomposing organic matter such as cellulose. These methane gases will diffuse through the nest system to the surface of the dam and the surrounding air, forming local areas of abnormal methane concentration. Based on this characteristic, this application proposes a method for locating termite nests on dams using methane laser technology.

[0046] Methane laser sensors are based on laser absorption spectroscopy technology. The core of the technology is to use the obvious absorption characteristics of methane gas molecules under infrared lasers of specific wavelengths (such as 1.65μm). Laser detection technology can accurately emit single-wavelength light, thereby effectively eliminating the interference of environmental gases and truly achieving single-wavelength scanning. Figure 5 As shown in the figure, it is an absorption spectrum diagram, which shows 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; When the laser passes through the methane concentration distribution area, the light intensity will attenuate due to the absorption of methane. By measuring the attenuation degree, the concentration distribution of methane gas can be accurately calculated; the concentration detected by the laser methane sensor is the cumulative concentration of the gas on the effective path of laser transmission; usually, the reflective linear beam detector system does not distinguish the gas concentration in the local interval on the working light path, that is, the effect of a small range of high-concentration gas and a large range of low-concentration gas is the same, and the unit of the sensor is the average concentration of the gas 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; 100%LEL*1M=50%LEL*2M=25%LEL*4M Methane laser technology has the characteristics of high sensitivity, high resolution and long-distance detection. Through the methane laser sensor, the methane concentration on the dam surface and in the surrounding air is scanned and monitored in real time, which 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.

[0047] 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.

[0048] Second, as Figure 7 As shown, the present application provides a non-contact close-range laser infrared fusion method for detecting termite nests, which specifically includes: Infrared imaging detectors are used to capture and analyze thermal signals in the target area. They detect the temperature difference between the heat generated by the termite nest and the environment through infrared imaging technology, thereby identifying and locating the nest; Laser methane detectors are used to accurately detect methane gas that may be present in termite nests based on laser absorption spectroscopy technology. Since methane is often associated with biological activity in termite nests, laser methane detectors can further confirm the location of the nest and provide information on gas concentration; Inertial navigation attitude locator, used to track 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; The information processor is responsible for collecting data from various detectors and conducting 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; The structure, material, temperature and other properties of ant nests are different from those of their surrounding environment. 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 thermal / light / chemical fields of the environmental background field in which they are located. This application, through the combination of multiple perceptions and physical and chemical characteristics, can efficiently, accurately and non-destructively locate termite nests in dams and other key areas, providing strong technical support for termite prevention and control.

[0049] Example 1 Figure 8 A visible light image of an ant nest taken in a certain area. Fig. 9 is the infrared image of the area; Figure 8 The middle oval red frame area is the exact location of the ant nest in the area; Fig. 9The elliptical red frame area in the figure corresponds to it; observing the infrared image of the ant nest, we can see that the thermal signal in the ant nest area is higher than that in the surrounding area, and the methane concentrations measured here are 258ppm, 538ppm, 829ppm, 569ppm, 1123ppm and 1266ppm; from this, it can be seen that in areas with sufficient methane concentration signals and sufficient thermal signals, there is a high probability that an ant nest exists underneath.

[0050] Example 2 Fig.10 is a visible light image of another area that is not an ant nest. Fig.11 is the infrared image of the area; Fig.11 The inner red box is a suspected area of ​​an ant nest, where the methane concentrations detected were 630ppm, 288ppm, 367ppm, 510ppm, 366ppm, 586ppm, 1069ppm, 827ppm and 745ppm. However, after digging up this area, no ant nest was found, so the location of the ant nest cannot be determined solely by the methane concentration. It can be seen that there are sufficient methane concentration signals but no sufficient heat signals in the area, and there is no ant nest underneath.

[0051] Example 3 Fig.12 for Figure 7 There is a vegetation area in the area where there is no ant nest. The thermal signal in this area is high, but the methane test result is 0ppm. Therefore, the suspected ant nest area cannot be confirmed by infrared thermal information alone.

[0052] To sum up, areas with sufficient methane concentration signals and sufficient heat signals may have ant nests underneath; areas with sufficient methane concentration signals but not sufficient heat signals do not have ant nests underneath; and areas with sufficient heat signals but not sufficient methane concentration signals.

[0053] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the scope of protection 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, the concentration of chemicals in the dam is measured; Step 2: Establish a dam surface radiation energy model including 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; wherein, the infrared remote sensing image of the dam surface is used to obtain the dam surface radiation energy, and at the same time, the dam background heat flow field heat and the background heat flow field energy at the corresponding position of the underground ant nest target are obtained based on the layered filtering method of the heat flow field energy of different soil layers; the solar radiation energy received by the dam is obtained by calculating the sum of the direct solar radiation and the scattered solar radiation; Step 3: Compare the thermal image area map with the dam background thermal flow field energy 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 is characterized in that: The model expression of the dam surface radiation energy in step 2 is: in, Radiate energy to the surface of the dam; is the background thermal flow field energy of the dam; It 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 is 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 at a certain depth from the dam surface. Realize the calculation of the 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 are regions in the thermal image region map where the thermal flow field has different energies from the dam background thermal flow field, and the thermal flow field corresponding to the thermal image region of the different regions is greater than the dam background thermal flow field energy, the different regions are regarded as termite nest regions; 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 detection system for termite nests, characterized in that: include: Infrared imaging detectors, laser methane detectors, inertial attitude locators and information processors; The infrared imaging detector is used to conduct infrared remote sensing scanning along the dam to obtain remote sensing images of the dam; 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 including 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; wherein, the infrared remote sensing image of the dam surface is used to obtain the dam surface radiation energy, and at the same time, the dam background heat flow field heat and the background heat flow field energy at the corresponding position of the underground ant nest target are obtained based on the layered filtering method of the heat flow field energy of different soil layers; the solar radiation energy received by the dam is calculated by the sum of 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 initially locate 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 is characterized in that: The model expression of the dam surface radiation energy in the model building module is: in, Radiate energy to the surface of the dam; is the background thermal flow field energy of the dam; It 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 with 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 at a certain depth from the dam surface. Realize the calculation of the 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 heat flow field in the thermal image area map is the same as the heat flow field energy of the dam background. When there are areas in the thermal image area map where the heat flow field has different energies from the heat flow field energy of the dam background, and the heat flow field corresponding to the thermal image area of ​​the different areas is greater than the heat flow field energy of the dam background, 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.

Images