A method for fine 3D modeling of rice plants for electromagnetic scattering simulation

Abstract

This invention provides a method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation, comprising: firstly, independently modeling the geometric morphology of each component of the rice plant to achieve fine three-dimensional modeling of the panicle structure refined to the grain scale, as well as the leaves and stems; based on this, further combining the spatial distribution relationship between the components to construct a three-dimensional plant model that effectively represents the true geometric morphology and physiological structural characteristics of rice; subsequently, calculating the electromagnetic scattering characteristics of the rice plant and its components using a three-dimensional full-wave electromagnetic solver, thereby providing physically consistent and high-precision scattering input parameters for modeling the rice canopy scattering mechanism.

Description

Technical Field

[0001] This invention relates to the field of agricultural remote sensing technology, and in particular to a method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation. Background Technology

[0002] Electromagnetic scattering from the vegetation canopy is one of the core scientific problems in the theoretical system of microwave scattering modeling. As a typical randomly distributed vegetation medium, the total backscattered energy of the paddy field canopy originates from the combined contributions of various components of the rice plant (including panicles, leaves, and stems). As the basic scattering units constituting the rice canopy, panicles, leaves, and stems can usually be abstracted as irregular geometric shapes with certain dielectric properties, and their electromagnetic scattering response is difficult to obtain an exact solution directly through analytical theoretical formulas. Given the high complexity of the geometric structure and spatial morphology of real rice components, existing microwave scattering models typically use regular geometric shapes (such as finite-length cylinders, elliptical disks, etc.) to approximate the above-mentioned rice components in order to reduce modeling and computational complexity. However, this simplification inevitably weakens the model's ability to represent actual scattering characteristics. Among these, the accurate description of the scattering characteristics of the panicle, as an important component of the rice plant, plays a crucial role in improving the accuracy of paddy field canopy backscattering simulations. Especially under high-frequency electromagnetic wave conditions, panicle scattering often becomes the dominant scattering mechanism of the paddy field canopy, accounting for a significant proportion of the total backscattering contribution. However, existing research on rice panicle scattering is relatively limited, and most studies employ coarse geometric approximations, lacking detailed characterization of the panicle's microstructure (such as the rachis, grains, and branches). This simplification in geometric modeling leads to significant deviations in electromagnetic scattering calculations, thus limiting the accuracy of simulating the backscattering coefficient of the paddy field canopy.

[0003] In existing technologies, a series of rice canopy electromagnetic scattering modeling methods based on simplified geometric structures have been proposed to address the problem. A typical approach involves decomposing the rice plant into basic components such as leaves, stems, and panicles, and approximating each component using regular geometric shapes. Then, the overall scattering characteristics of the canopy are solved based on electromagnetic scattering theory. Specifically, in these methods, leaves are typically simplified to disks, elliptical disks, or rectangular dielectric sheets; stems are often represented by finite-length solid or hollow cylinders; and for the panicle structure, existing methods typically use needle-like cylinders or finite-length cylinders for equivalent modeling, or consider it as an extension of the stem, or use a modeling method that combines multiple simple cylinders to represent the panicle. Based on this, the aforementioned components are combined according to certain spatial distribution rules to construct an electromagnetic scattering model of the rice plant or canopy.

[0004] The aforementioned methods, by simplifying the representation of rice components using regular geometric shapes, reduce modeling and computational complexity to some extent, offering advantages such as simplicity and high computational efficiency. Therefore, they are widely used in the analysis of microwave scattering characteristics of rice canopies and in remote sensing modeling research. However, a common drawback of these methods is their coarse description of the geometric structure of rice components, particularly the severely simplified modeling of the panicle structure, which fails to effectively reflect its true microscopic composition characteristics (such as the rachis, grains, and branches). Under high-frequency electromagnetic wave conditions, panicle scattering significantly contributes to the total backscattering of the rice canopy. The aforementioned simplification leads to inaccurate descriptions of the scattering mechanism, thus affecting the accuracy of electromagnetic scattering calculations. Furthermore, these models have limited adaptability to different observation conditions and growth states, making it difficult to meet the requirements of high-precision scattering modeling.

[0005] Therefore, it is necessary to develop a three-dimensional modeling method that can realistically reflect the geometric morphology and structural characteristics of rice plants in order to improve the physical consistency and computational accuracy of electromagnetic scattering modeling. Summary of the Invention

[0006] This invention provides a method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation, in order to overcome the deficiencies in the existing technology.

[0007] In a first aspect, the present invention provides a method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation, comprising: Obtain geometric parameters and physiological characteristic parameters of rice plants, wherein the geometric parameters include the number of grains per panicle, leaf length, and stem diameter, and the physiological characteristic parameters include water content; Based on the geometric parameters and physiological characteristic parameters, three-dimensional geometric morphology models of the rice panicle, leaves and stem of the rice plant are respectively performed; Based on the actual growth parameters of the rice plant, the spatial distribution relationship and relative position constraints between the rice panicle, the leaves and the stem are constructed, and the components are combined in three-dimensional space to generate an overall three-dimensional structural model of the rice plant; wherein, the geometric parameters of each component meet the preset statistical distribution characteristics. The overall three-dimensional structural model of the rice plant is input into the full-wave electromagnetic solver. By setting the electromagnetic simulation parameters and performing mesh generation, the electromagnetic scattering characteristic parameters of the rice plant and its components are calculated. Based on the electromagnetic scattering characteristic parameters, physically meaningful scattering feature parameters are extracted for modeling electromagnetic scattering in rice canopy.

[0008] According to the present invention, a method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation is provided, which performs three-dimensional geometric morphology modeling of rice panicles, including: The central axis of the rice panicle is simulated by a Gaussian curve. Based on the measured panicle initiation angle and panicle termination angle, the elevation angle at each sampling point on the panicle is calculated by a Gaussian function to generate a curved panicle curve. Primary branches, secondary branches, and twigs are sequentially added to the rachis curve. The starting points of the primary branches are evenly distributed along the rachis curve, and their initial elevation angle is the same as the elevation angle of the rachis curve at the corresponding starting point, but deviates from the rachis plane in the azimuth direction. The starting points of the secondary branches are evenly distributed along the primary branches, and their initial elevation angle is the same as the elevation angle of the primary branch at the corresponding starting point, but deviates from the primary branch plane in the azimuth direction. Both the branches and twigs are simulated using Gaussian curves. By adding ellipsoidally simulated panicle grains to the end of the branchlets, a fine three-dimensional model of the rice panicle is obtained, refined to the scale of the panicle grains.

[0009] According to the present invention, a method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation is provided, which includes three-dimensional geometric morphology modeling of leaves, including: Hermite curves were used to simulate the edge contour of rice leaves, and two symmetrical Hermite curves were used to construct the complete outline of rice leaves. The blade contour points are generated by interpolating the Hermite curve, and the contour points are connected in sequence to generate a planar blade model. The central axis of the curved blade is simulated by a Gaussian curve. The central axis is sampled, and the sampled points on the central axis and the blade contour points are connected in sequence to realize the three-dimensional modeling of the curved blade geometry represented by triangular facets.

[0010] According to the present invention, a method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation is provided, which includes three-dimensional geometric morphology modeling of the stem, including: Based on the measured stem geometric parameters, a finite-length cylinder is used to simulate the stem; the stem geometric parameters include at least the stem diameter, stem length, and stem inclination angle.

[0011] According to the present invention, a method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation is provided, which constructs the spatial distribution relationship and relative position constraints between the rice panicles, the leaves, and the stems, including: Assuming that the base of the leaves is evenly distributed on the stem, the rice ear is connected to the top of the stem, and the leaves, the stem, and the rice ear are randomly distributed in terms of orientation; The leaves at the top are approximately upright, and their orientation is opposite to that of the rice ears.

[0012] According to the present invention, a method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation is provided, wherein the geometric parameters of each component satisfy a preset statistical distribution characteristic, including: Assuming that the geometric parameters of each component follow a normal distribution, the mean and standard deviation of the corresponding parameters are calculated based on the measured geometric parameters of each component. A random variable constrained by the standard deviation is added to the mean as an input parameter for modeling the three-dimensional geometry of each component.

[0013] According to the present invention, a three-dimensional fine modeling method for rice plants for electromagnetic scattering simulation is provided, wherein the full-wave electromagnetic solver uses the method of moments to perform electromagnetic scattering simulation calculations. The electromagnetic simulation parameters include at least frequency, polarization, incident angle, and dielectric constant.

[0014] According to the present invention, a three-dimensional fine modeling method for rice plants for electromagnetic scattering simulation is provided, wherein the electromagnetic scattering characteristic parameters include the backscattering electric field of the rice plant and its components under different frequencies, polarization modes, incident angles and azimuth angles. The scattering characteristic parameters include moisture content and grain density.

[0015] The present invention provides a method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation, which further includes: A rice canopy scene of a preset size is constructed to simulate the attenuation effect of the canopy on electromagnetic waves. The scattering process and scattering mechanism of different plants or components are synthesized to calculate the total backscattering electric field of the rice canopy scene, thus realizing the electromagnetic scattering simulation at the canopy scale.

[0016] Secondly, the present invention also provides a three-dimensional fine modeling system for rice plants for electromagnetic scattering simulation, comprising: The data acquisition module is used to acquire the geometric parameters and physiological characteristic parameters of rice plants. The geometric parameters include the number of grains per panicle, leaf length, and stem diameter, and the physiological characteristic parameters include water content. The component modeling module is used to perform three-dimensional geometric morphology modeling of the rice panicle, leaves and stem of the rice plant based on the geometric parameters and the physiological characteristic parameters, respectively. The plant assembly module is used to construct the spatial distribution relationship and relative position constraints between the rice panicles, leaves and stems based on the actual growth parameters of the rice plant, and to combine the components in three-dimensional space to generate an overall three-dimensional structural model of the rice plant; wherein the geometric parameters of each component meet the preset statistical distribution characteristics. The electromagnetic simulation module is used to input the overall three-dimensional structural model of the rice plant into the full-wave electromagnetic solver. By setting the electromagnetic simulation parameters and performing mesh generation, the electromagnetic scattering characteristic parameters of the rice plant and its components are calculated. The parameter extraction module is used to extract physically meaningful scattering feature parameters based on the electromagnetic scattering characteristic parameters, for modeling electromagnetic scattering in rice canopy.

[0017] The method for detailed 3D modeling of rice plants for electromagnetic scattering simulation provided by this invention has the following beneficial effects: (1) Improve the realism and physical consistency of geometric modeling This invention differs from traditional modeling methods that use regular geometric shapes to approximate rice components. By performing refined three-dimensional modeling of each component of the rice plant, especially refining the expression of the rice panicle structure to the grain scale, the model can more realistically reflect the actual geometric shape and structural characteristics of the rice plant, thereby improving the physical consistency of the model.

[0018] (2) Enhance the ability to characterize the scattering mechanism of rice ears and improve the accuracy of electromagnetic scattering simulation. Because the structural representation of key scattering units (especially rice ears) is more detailed and realistic, three-dimensional full-wave electromagnetic simulation of the model can obtain a scattering response that is closer to the real situation, effectively making up for the problem of insufficient characterization of rice ear scattering mechanism in existing technologies, thereby effectively improving the simulation accuracy of rice ear backscattering characteristics.

[0019] (3) Improve the applicability of the model under different observation conditions and enhance the model's scalability and application potential. The three-dimensional model constructed in this invention can adapt to the electromagnetic scattering calculation requirements under different frequencies, polarization modes, and observation geometries, enhancing the model's stability and applicability in multiple scenarios. By adopting a structured modeling approach using measured parameters, it is easy to adjust according to the geometric characteristics of different growth stages or different rice varieties, exhibiting good scalability and further applicable to fields such as microwave remote sensing inversion and agricultural monitoring.

[0020] (4) Provide high-quality input parameters for canopy-scale scattering modeling By performing high-precision calculations on the scattering characteristics of rice components and plants, this invention helps to extract scattering feature parameters with clear physical meaning, providing high-precision and physically consistent input for rice canopy electromagnetic scattering simulation, and improving the reliability and accuracy of canopy modeling. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a flowchart illustrating the method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation provided by the present invention. Figure 2 This is a schematic diagram of the rice ear structure provided by the present invention; Figure 3 This is a schematic diagram simulating rice ears and leaves provided by the present invention, wherein... Figure 3 (a) in the figure represents a simulation of the rice spike and leaf axis. Figure 3 (b) in the figure represents the blade profile simulation; Figure 4 This is a schematic diagram of the structure of the three-dimensional fine modeling system for rice plants for electromagnetic scattering simulation provided by the present invention; Figure 5 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0024] To address the common problems in existing rice canopy electromagnetic scattering modeling, such as coarse representation of component geometry, insufficient characterization of rice spike scattering mechanism, and weak physical consistency of scattering parameters, this invention proposes a three-dimensional fine modeling method for rice plants for electromagnetic scattering simulation.

[0025] Unlike traditional simplified modeling methods based on regular geometry, this invention does not simply refine the geometry of rice components. Instead, it uses electromagnetic scattering mechanisms (such as direct backscattering, forward scattering, and bistatic scattering) as constraints to create a physically meaningful structured model of each component of the rice plant, enabling the constructed geometric units to directly participate in electromagnetic scattering calculations. Specifically, compared to the traditional equivalent cylindrical model, this invention introduces panicle-level scattering units during panicle modeling. The panicle is represented as a discrete structure composed of the panicle axis, branches, and multiple panicle units with dielectric properties. Spatial arrangement rules describe the distribution characteristics of the panicle grains on the panicle axis, thus establishing a multi-scale scattering structure model of the rice panicle. This structure can explicitly characterize the microscopic composition of the panicle, achieving high-precision simulation of the electromagnetic scattering characteristics of the rice panicle. Furthermore, based on the actual growth parameters of the rice plant, this invention constructs spatial distribution relationships and relative position constraints between the panicle, leaves, and stems, ensuring that the distribution of each component in three-dimensional space satisfies statistical structural characteristics, thereby guaranteeing the physical consistency of the overall model in an electromagnetic sense. Based on this, the constructed three-dimensional structural model is input into a full-wave electromagnetic solver (such as FEKO, HFSS, etc.) to calculate the scattering response of rice plants and their constituent units, and extract scattering characteristic parameters with physical significance (such as water content, panicle density, etc.) for modeling electromagnetic scattering of the paddy field canopy.

[0026] Figure 1 This is a flowchart illustrating the method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation provided in this embodiment of the invention. Figure 1 As shown, it includes: Step 100: Based on the obtained geometric parameters and physiological characteristic parameters of rice plants, the geometric parameters include the number of grains per panicle, leaf length, and stem diameter, and the physiological characteristic parameters include water content; Step 200: Based on the geometric parameters and the physiological characteristic parameters, perform three-dimensional geometric morphology modeling of the rice panicle, leaves and stem of the rice plant respectively; Step 300: Based on the actual growth parameters of the rice plant, construct the spatial distribution relationship and relative position constraints between the rice panicle, the leaves and the stem, and combine the components in three-dimensional space to generate an overall three-dimensional structural model of the rice plant; wherein, the geometric parameters of each component meet the preset statistical distribution characteristics; Step 400: Input the overall three-dimensional structural model of the rice plant into the full-wave electromagnetic solver, and calculate the electromagnetic scattering characteristic parameters of the rice plant and its components by setting the electromagnetic simulation parameters and performing mesh generation. Step 500: Based on the electromagnetic scattering characteristic parameters, extract physically meaningful scattering feature parameters for modeling electromagnetic scattering in rice canopy.

[0027] First, the geometry of each component of the rice plant is modeled independently, achieving detailed 3D modeling of the panicle structure down to the grain scale, as well as the leaves and stems. Based on this, a 3D plant model is constructed by combining the spatial distribution relationships between the components to effectively represent the true geometric morphology and physiological structure of the rice plant. Subsequently, the electromagnetic scattering characteristics of the rice plant and its components are calculated using a 3D full-wave electromagnetic solver, thus providing physically consistent and highly accurate scattering input parameters for modeling the rice canopy scattering mechanism.

[0028] Specifically, the specific implementation steps of this invention are as follows: (1) Data acquisition and processing. Select several representative rice plants, measure and obtain the geometric (such as number of grains per panicle, leaf length, stem diameter, etc.) and physiological characteristics (such as water content) parameters of the rice plants, calculate the average value of multiple measurements of each parameter, and provide input parameters for the three-dimensional modeling of the geometric morphology of rice components.

[0029] (2) Three-dimensional modeling of the geometric morphology of rice ears. For example... Figure 2 As shown, a rice panicle consists of the rachis, primary branches, secondary branches, twigs, and grains. When rice first emerges, the panicle is largely straight. As dry matter accumulates and the panicle's weight increases, it gradually begins to bend. The central axis of the bent panicle is simulated using a Gaussian curve, the grains using an ellipsoid, and the branches using slender cylinders. The steps for modeling the rice panicle's geometric morphology include: 1) simulating the rachis curve; 2) adding primary branches, secondary branches, and twigs; and 3) simulating the grains on the primary and secondary branches.

[0030] The axis of a rice spike can be represented as a smooth curve in space, such as... Figure 3 As shown in (a), the curve is sampled, and the sampling points are connected end to end, which is represented as: (1) Among them, point The coordinates at the location are represented as , Indicates from point Point of view The vector, Representing vectors Length, This indicates the number of sampling points on the ear axis. express and The unit direction vector between two points.

[0031] Assuming the ears of grain lie on the same plane, then the azimuth angles of each point on the ear axis curve are... Same, elevation angle The angle changes continuously from the panicle node to the panicle tail. Based on the measured panicle initiation angle and panicle tail angle, the elevation angle at the sampling point on the panicle axis is calculated using a Gaussian function, expressed as: (2) In equation (2), Point The tangent direction at the point and The angle between the positive axis and the axis, when lie in When above, ,when lie in When below, . This indicates the relative position of the sampling point on the ear axis curve, that is, the ratio of the length from the point on the ear axis curve to the ear node to the total length of the ear axis curve. The altitude angle at the ear node, i.e., the ear initiation angle. This indicates the range of elevation angle variation from the ear node to the ear tail point. It is a Gaussian function used to simulate the rate of change of the elevation angle along the ear axis curve, with parameters... and The effect on the shape of the ear axis curve can be expressed as: (3) (4) in, , Indicates the sampling point number. This indicates the relative position of the point on the ear axis curve where the elevation angle changes the most rapidly. Indicates the smoothness of the ear axis curve. This indicates the altitude angle of the ear tail point, i.e., the ear tail angle.

[0032] Based on the above method, after simulating the rice panicle axis, primary branches, secondary branches, and twigs are added to the axis. The branches and twigs are also considered smooth curves in space, and their simulation method is the same as that of the panicle axis, i.e., Gaussian curves are still used to simulate the branches and twigs. The specific process is as follows: 1) First, primary branches are added to the panicle axis. The starting points of the primary branches are evenly distributed on the panicle axis, and their initial elevation angle is the same as the elevation angle of the panicle axis at the starting point of the primary branch, but they deviate from the plane of the panicle axis in the azimuth direction. 2) Then, secondary branches are added to the primary branches. The starting points of the secondary branches are evenly distributed on the primary branches, and their initial elevation angle is the same as the elevation angle of the primary branch at the starting point of the secondary branch, but they deviate from the plane of the primary branch in the azimuth direction. 3) Add twigs, mainly located on secondary branches, with a small number also distributed on primary branches. The other end of each twig is connected to a grain in the panicle, and its initial elevation angle is the same as that of the secondary or primary branch at the starting point of the twig, and it deviates from the plane of the secondary or primary branch in the azimuth direction. 4) Finally, add grains to the ends of the twigs to obtain a refined three-dimensional model of the rice panicle at the grain scale.

[0033] (3) Three-dimensional modeling of leaf geometry. In its natural state, rice leaves are curved, and the curvature of leaves varies among different plants and at different locations, which increases the complexity of leaf modeling. The method proposed in this patent is applicable to the simulation of leaves with different curvatures. The leaf edge contour is simulated using Hermite curves, and the curved leaf axis is simulated using Gaussian curves. The steps of leaf geometry modeling include: 1) Hermite curve representation of the edge contour; 2) Interpolation of edge contour points; 3) Establishment of planar leaf model; 4) Simulation of curved leaf.

[0034] The Hermite curve is used to simulate the blade profile. The equation of the Hermite curve is expressed as: (5) Here, a, b, c, and d are the four coefficients of the Hermite curve equation. Changing these coefficients can control the shape of the Hermite curve.

[0035] Typically, a curve can be uniquely defined by two points and their tangent vector. For example... Figure 3 As shown in (b), assuming the Hermite curve is in and The tangent vectors of the points are respectively and Then we have: (6) in, It is the Hermite constant matrix. The parameters in equation (6) can be expressed as follows: (This represents the Hermite geometric vector.) (7) (8) (9) Under different initial conditions, only They are different, and and They are all the same. Therefore, as long as given Then, the corresponding Hermite curve can be obtained. According to equation (8), only two endpoints need to be given. and The coordinates and the tangent vectors at the two endpoints and The Hermite curve can be constructed by using the tangent vectors at its two endpoints, where the magnitude and direction determine the shape of the curve. However, since these tangent vectors are difficult to control, we consider introducing another point. To jointly define the Hermite curve, that is, with and Representing the endpoints respectively and The tangent vector at that point, by changing The position allows control over the shape of the Hermite curve.

[0036] Based on the above method, the Hermite curve representation of the rice leaf outline is first given. Then, two symmetrical Hermite curves are used to simulate the complete rice leaf outline. Finally, leaf outline points are generated by interpolating the Hermite curves. The resulting leaf outline points are represented as follows: (10) in, , This indicates the number of interpolation points on the blade profile curve. Indicates the first Interpolation points. After generating the blade contour points, the points are connected in sequence to generate a planar blade model. Then, using the method described in step (2), the central axis of the curved blade is simulated based on a Gaussian curve, the blade axis is sampled, and the blade axis points and contour points are connected in sequence to realize the three-dimensional modeling of the curved blade geometry represented by triangular facets.

[0037] (4) Three-dimensional modeling of the stem geometry. Based on the measured geometric parameters of the rice stem (diameter, length, inclination angle, etc.), the stem is simulated by a finite-length cylinder.

[0038] (5) 3D modeling of rice plants. Rice plants consist of panicles, stems, and several leaves. The parameters of panicles, leaves, and stems vary among different plants (such as the number of grains per panicle, stem length, and leaf curvature). In order to accurately depict rice plants, based on the detailed 3D modeling of components, it is necessary to consider the panicle type (upright and curved), number of grains per panicle, panicle length, panicle inclination angle (initial and terminal angles), leaf type (upright and curved), length, width, leaf inclination angle (initial and terminal angles), number and position distribution of leaves, as well as the changes in parameters such as stem diameter, length, and stem inclination angle.

[0039] Assuming the above geometric parameters satisfy a normal distribution, firstly, based on the measured geometric parameters of different rice components, the mean and standard deviation of the corresponding parameters are calculated. By adding random variables constrained by the standard deviation to the mean of the geometric parameters of each component, three-dimensional geometric structure models of rice panicles, leaves, and stems are established respectively by steps (2)-(4). Then, based on the actual growth parameters of rice, the above rice components are combined to construct the spatial distribution relationship and relative position constraints of different components, thereby realizing the simulation of the overall three-dimensional structure of the rice plant. Specifically, it is assumed that the leaves are evenly distributed on the stem, the rice panicles are connected to the top of the stem, and the leaves, stems, and rice panicles are randomly distributed in terms of orientation, wherein the top leaves are approximately upright leaves, and their orientation is opposite to that of the rice panicles.

[0040] (6) Electromagnetic scattering characteristics simulation calculation. Input the geometric model constructed in steps (2)-(5) into the three-dimensional full-wave electromagnetic solver, set the electromagnetic simulation parameters (frequency, polarization, incident angle, dielectric constant, etc.) for different scattering mechanisms, perform model meshing, set the solution algorithm (method of moments, etc.), and perform electromagnetic scattering simulation calculation of rice components and plants.

[0041] (7) Extraction of scattering results. Extract the electromagnetic scattering field of rice components and plants from the output results of step (6), analyze the scattering process and mechanism of rice components and plants under different radar observation conditions (frequency, polarization, incident angle, azimuth angle), and provide input parameters for canopy-scale electromagnetic scattering simulation.

[0042] (8) Construction of rice canopy scattering model. Construct a rice canopy scene of a certain size (e.g., 1 × 1 m) to simulate the attenuation effect of the canopy on electromagnetic waves. Combine the scattering process and mechanism of different components or plants to calculate the total backscattering electric field of the rice scene and realize the simulation of electromagnetic scattering at the canopy scale.

[0043] The following describes the three-dimensional fine modeling system for rice plants oriented towards electromagnetic scattering simulation provided by the present invention. The three-dimensional fine modeling system for rice plants oriented towards electromagnetic scattering simulation described below can be referred to in correspondence with the three-dimensional fine modeling method for rice plants oriented towards electromagnetic scattering simulation described above.

[0044] Figure 4 This is a schematic diagram of the structure of a three-dimensional fine modeling system for rice plants for electromagnetic scattering simulation provided in an embodiment of the present invention, as shown below. Figure 4 As shown, it includes: a data acquisition module 41, a component modeling module 42, a plant assembly module 43, an electromagnetic simulation module 44, and a parameter extraction module 45, wherein: The data acquisition module 41 is used to acquire the geometric parameters and physiological characteristic parameters of the rice plant. The geometric parameters include the number of grains per panicle, leaf length, and stem diameter. The physiological characteristic parameters include water content. The component modeling module 42 is used to perform three-dimensional geometric morphology modeling of the rice panicle, leaves, and stem of the rice plant based on the geometric parameters and physiological characteristic parameters. The plant assembly module 43 is used to construct the spatial distribution relationship and relative position constraints between the rice panicle, leaves, and stem based on the actual growth parameters of the rice plant, and combine the components in three-dimensional space to generate an overall three-dimensional structural model of the rice plant. The geometric parameters of each component meet the preset statistical distribution characteristics. The electromagnetic simulation module 44 is used to input the overall three-dimensional structural model of the rice plant into a full-wave electromagnetic solver, and calculate the electromagnetic scattering characteristic parameters of the rice plant and each component by setting electromagnetic simulation parameters and performing mesh generation. The parameter extraction module 45 is used to extract physically meaningful scattering characteristic parameters based on the electromagnetic scattering characteristic parameters for modeling the electromagnetic scattering of the rice canopy.

[0045] Figure 5 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 5As shown, the electronic device may include: a processor 510, a communication interface 520, a memory 530, and a communication bus 540, wherein the processor 510, the communication interface 520, and the memory 530 communicate with each other through the communication bus 540. The processor 510 can call logic instructions in the memory 530 to execute a three-dimensional fine modeling method for rice plants for electromagnetic scattering simulation. This method includes: acquiring geometric parameters and physiological characteristic parameters of the rice plant, where the geometric parameters include the number of grains per panicle, leaf length, and stem diameter, and the physiological characteristic parameters include water content; based on the geometric parameters and physiological characteristic parameters, performing three-dimensional geometric morphology modeling of the rice panicle, leaves, and stem of the rice plant; based on the actual growth parameters of the rice plant, constructing the spatial distribution relationship and relative position constraints between the rice panicle, leaves, and stem, and combining the components in three-dimensional space to generate an overall three-dimensional structural model of the rice plant; wherein the geometric parameters of each component satisfy preset statistical distribution characteristics; inputting the overall three-dimensional structural model of the rice plant into a full-wave electromagnetic solver, calculating the electromagnetic scattering characteristic parameters of the rice plant and its components by setting electromagnetic simulation parameters and performing mesh generation; and extracting physically meaningful scattering characteristic parameters based on the electromagnetic scattering characteristic parameters for modeling the electromagnetic scattering of the rice canopy.

[0046] Furthermore, the logical instructions in the aforementioned memory 530 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0047] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0048] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation, characterized in that, include: Obtain geometric parameters and physiological characteristic parameters of rice plants, wherein the geometric parameters include the number of grains per panicle, leaf length, and stem diameter, and the physiological characteristic parameters include water content; Based on the geometric parameters and physiological characteristic parameters, three-dimensional geometric morphology models of the rice panicle, leaves and stem of the rice plant are respectively performed; Based on the actual growth parameters of the rice plant, the spatial distribution relationship and relative position constraints between the rice panicle, the leaves and the stem are constructed, and the components are combined in three-dimensional space to generate an overall three-dimensional structural model of the rice plant; wherein, the geometric parameters of each component meet the preset statistical distribution characteristics. The overall three-dimensional structural model of the rice plant is input into the full-wave electromagnetic solver. By setting the electromagnetic simulation parameters and performing mesh generation, the electromagnetic scattering characteristic parameters of the rice plant and its components are calculated. Based on the electromagnetic scattering characteristic parameters, physically meaningful scattering feature parameters are extracted for modeling electromagnetic scattering in rice canopy.

2. The method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation according to claim 1, characterized in that, Three-dimensional geometric modeling of rice ears, including: The central axis of the rice panicle is simulated by a Gaussian curve. Based on the measured panicle initiation angle and panicle termination angle, the elevation angle at each sampling point on the panicle is calculated by a Gaussian function to generate a curved panicle curve. Primary branches, secondary branches, and twigs are sequentially added to the rachis curve. The starting points of the primary branches are evenly distributed along the rachis curve, and their initial elevation angle is the same as the elevation angle of the rachis curve at the corresponding starting point, but deviates from the rachis plane in the azimuth direction. The starting points of the secondary branches are evenly distributed along the primary branches, and their initial elevation angle is the same as the elevation angle of the primary branch at the corresponding starting point, but deviates from the primary branch plane in the azimuth direction. Both the branches and twigs are simulated using Gaussian curves. By adding ellipsoidally simulated panicle grains to the end of the branchlets, a fine three-dimensional model of the rice panicle is obtained, refined to the scale of the panicle grains.

3. The method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation according to claim 1, characterized in that, Three-dimensional geometric modeling of the blades includes: Hermite curves were used to simulate the edge contour of rice leaves, and two symmetrical Hermite curves were used to construct the complete outline of rice leaves. The blade contour points are generated by interpolating the Hermite curve, and the contour points are connected in sequence to generate a planar blade model. The central axis of the curved blade is simulated by a Gaussian curve. The central axis is sampled, and the sampled points on the central axis and the blade contour points are connected in sequence to realize the three-dimensional modeling of the curved blade geometry represented by triangular facets.

4. The method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation according to claim 1, characterized in that, Three-dimensional geometric modeling of the stem, including: Based on the measured stem geometric parameters, a finite-length cylinder is used to simulate the stem; the stem geometric parameters include at least the stem diameter, stem length, and stem inclination angle.

5. The method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation according to claim 1, characterized in that, Constructing the spatial distribution relationship and relative position constraints among the rice panicles, leaves, and stems includes: Assuming that the base of the leaves is evenly distributed on the stem, the rice ear is connected to the top of the stem, and the leaves, the stem, and the rice ear are randomly distributed in terms of orientation; The leaves at the top are approximately upright, and their orientation is opposite to that of the rice ears.

6. The method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation according to claim 5, characterized in that, The geometric parameters of each component satisfy preset statistical distribution characteristics, including: Assuming that the geometric parameters of each component follow a normal distribution, the mean and standard deviation of the corresponding parameters are calculated based on the measured geometric parameters of each component. A random variable constrained by the standard deviation is added to the mean as an input parameter for modeling the three-dimensional geometry of each component.

7. The method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation according to claim 1, characterized in that, The full-wave electromagnetic solver uses the method of moments to perform electromagnetic scattering simulation calculations. The electromagnetic simulation parameters include at least frequency, polarization, incident angle, and dielectric constant.

8. The method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation according to claim 1, characterized in that, The electromagnetic scattering characteristic parameters include the backscattered electric fields of the rice plant and its components under different frequencies, polarization modes, incident angles, and azimuth angles. The scattering characteristic parameters include moisture content and grain density.

9. The method for fine three-dimensional modeling of rice plants for electromagnetic scattering simulation according to claim 1, characterized in that, Also includes: A rice canopy scene of a preset size is constructed to simulate the attenuation effect of the canopy on electromagnetic waves. The scattering process and scattering mechanism of different plants or components are synthesized to calculate the total backscattering electric field of the rice canopy scene, thus realizing the electromagnetic scattering simulation at the canopy scale.

10. A three-dimensional fine modeling system for rice plants for electromagnetic scattering simulation, characterized in that, include: The data acquisition module is used to acquire the geometric parameters and physiological characteristic parameters of rice plants. The geometric parameters include the number of grains per panicle, leaf length, and stem diameter, and the physiological characteristic parameters include water content. The component modeling module is used to perform three-dimensional geometric morphology modeling of the rice panicle, leaves and stem of the rice plant based on the geometric parameters and the physiological characteristic parameters, respectively. The plant assembly module is used to construct the spatial distribution relationship and relative position constraints between the rice panicles, leaves and stems based on the actual growth parameters of the rice plant, and to combine the components in three-dimensional space to generate an overall three-dimensional structural model of the rice plant; wherein the geometric parameters of each component meet the preset statistical distribution characteristics. The electromagnetic simulation module is used to input the overall three-dimensional structural model of the rice plant into the full-wave electromagnetic solver. By setting the electromagnetic simulation parameters and performing mesh generation, the electromagnetic scattering characteristic parameters of the rice plant and its components are calculated. The parameter extraction module is used to extract physically meaningful scattering feature parameters based on the electromagnetic scattering characteristic parameters, for modeling electromagnetic scattering in rice canopy.

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