A method and device for collecting and calculating two-dimensional mangrove coast plane parameters

Abstract

The present application discloses a two-dimensional mangrove coastal plane parameter acquisition and calculation method and device, which relates to the field of image data processing technology. The method comprises obtaining a mangrove image and measured parameters of a target mangrove area; determining the mangrove characteristic relationship of the target mangrove area according to the mangrove image and the measured parameters; calculating the mangrove distribution parameters according to the mangrove image; calculating the wave-breaking parameters according to the mangrove distribution parameters and the mangrove characteristic relationship; the wave-breaking parameters include an attenuation coefficient and a drag force parameter; determining the wave height change along the mangroves in the target mangrove area according to the wave-breaking parameters and the mangrove distribution parameters, which is used to characterize the wave-breaking capacity of the mangroves in the target mangrove area. The present application can accurately obtain the mangrove coastal plane parameters and improve the accuracy of the mangrove coastal plane parameters.

Description

Technical Field

[0001] The present application relates to the field of image data processing and computing technology, and in particular to a method and device for collecting and computing two-dimensional mangrove coast plane parameters. Background Art

[0002] Mangrove barriers are an important part of coastal protection. Mangroves have important functions such as wave and current reduction, tsunami mitigation, pollution absorption, wind protection, and wave reduction. Attenuation coefficient and drag force parameter are two key parameters frequently used to measure wave reduction capacity, which are usually calculated using physical experiments or field observation data.

[0003] Among them, physical experiments usually use a certain scaled-down model and a given plant spacing in a water tank to determine the wave-breaking parameters under a certain working condition, and obtain the wave-breaking parameter distribution curve through a large number of experimental fittings to estimate the wave-breaking capacity of specific plants and specific arrangements. However, in reality, the arrangement spacing of mangroves is not consistent, and the shape and distribution are also different. It is difficult to arrange and combine different physical model types and distribution spacing in physical experiments, so that the wave-breaking capacity of mangroves calculated in the end is not accurate. At present, it is a more optimized process to use physical model experiments to obtain the key wave-breaking parameters under the typical structure and typical arrangement of mangroves, and then perform two-dimensional mathematical model calculations based on the actual different shapes and plane distributions of mangroves. However, the current research on the wave-breaking capacity of mangrove coasts lacks a large-scale two-dimensional mathematical model that takes into account the actual shape and distribution of mangroves on the plane. And studying how to accurately obtain the plane parameters of mangrove coasts is the premise and basic work for designing physical and mathematical models, and it is also the key to studying the wave-breaking capacity of complex mangrove coasts.

[0004] In summary, how to provide a method for accurately obtaining the mangrove coast plane parameters has become a technical problem that needs to be urgently solved in this field. Summary of the invention

[0005] The purpose of this application is to provide a two-dimensional mangrove coast plane parameter acquisition and calculation method and device, which can accurately obtain the mangrove coast plane parameters and improve the accuracy of the mangrove coast plane parameters.

[0006] To achieve the above objectives, this application provides the following solutions.

[0007] In a first aspect, the present application provides a two-dimensional mangrove coast plane parameter collection and calculation method, and the two-dimensional mangrove coast plane parameter collection and calculation method includes the following steps.

[0008] Obtain a mangrove image and measured parameters of a target mangrove area; the mangrove image is a two-dimensional mangrove coast plane image obtained directly above the target mangrove area, and the measured parameters are data obtained by field measurement of mangroves in the target mangrove area, and the measured parameters include the number of mangroves, root length, root diameter, trunk length, trunk slope, trunk diameter, leaf shape, leaf number and leaf area.

[0009] According to the mangrove image and the measured parameters, a mangrove characteristic relationship of the target mangrove area is determined; the mangrove characteristic relationship is used to characterize the correlation between the crown diameter of the mangrove and the roots, branches and leaves respectively.

[0010] According to the mangrove image, mangrove distribution parameters are calculated; the mangrove distribution parameters include mangrove distribution density, average crown area, average crown diameter and average mangrove spacing.

[0011] According to the mangrove distribution parameters and the mangrove characteristic relationship, wave-breaking parameters are calculated; the wave-breaking parameters include an attenuation coefficient and a drag force parameter.

[0012] The wave height variation along the mangroves in the target mangrove area is determined according to the wave-breaking parameters and the mangrove distribution parameters; the wave height variation is used to characterize the wave-breaking capacity of the mangroves in the target mangrove area.

[0013] In a second aspect, the present application provides a two-dimensional mangrove coast plane parameter collection and calculation device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the two-dimensional mangrove coast plane parameter collection and calculation method described in the first aspect.

[0014] According to the specific embodiments provided in this application, this application discloses the following technical effects.

[0015] The present application provides a method and device for collecting and calculating two-dimensional mangrove coastal plane parameters. According to mangrove images and measured parameters, the correlation between the crown diameter of mangroves and roots, branches and leaves is established, and according to the mangrove images, mangrove distribution parameters such as mangrove distribution density, average crown area, average crown diameter and average mangrove spacing are calculated. Combined with the correlation between the crown diameter of mangroves and roots, branches and leaves, wave-breaking parameters such as attenuation coefficient and drag force parameter are jointly calculated, and the process of combining two-dimensional images with three-dimensional data for the calculation of drag force parameters and mathematical simulation is realized. The mangrove coastal plane parameters can be accurately obtained, and the accuracy of the mangrove coastal plane parameters is improved, which is conducive to more accurate and reliable evaluation of the wave-breaking capacity of mangroves. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic flow chart of a method for collecting and calculating two-dimensional mangrove coast plane parameters provided in one embodiment of the present application.

[0018] Figure 2 A schematic diagram of the principle of a two-dimensional mangrove coast plane parameter acquisition and calculation method provided in one embodiment of the present application. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0020] like Figure 1 and Figure 2 As shown, this embodiment proposes a two-dimensional mangrove coast plane parameter collection and calculation method, and the two-dimensional mangrove coast plane parameter collection and calculation method specifically includes the following steps.

[0021] Step S1, obtaining a mangrove image and measured parameters of a target mangrove area; the mangrove image is a two-dimensional mangrove coast plane image obtained directly above the target mangrove area, and the measured parameters are data obtained by field measurement of mangroves in the target mangrove area, and the measured parameters include the number of mangroves, root length, root diameter, trunk length, trunk slope, trunk diameter, leaf shape, leaf number and leaf area, etc.

[0022] In this embodiment, step S1 acquires the mangrove image and measured parameters of the target mangrove area, which specifically includes the following steps.

[0023] Step S11, obtaining a mangrove image of a target mangrove area, wherein the mangrove image is an image obtained by plane mapping the mangroves in the target mangrove area using a drone.

[0024] In this embodiment, a high-precision, high-definition mangrove image is obtained by plane mapping using a drone, including clear mangrove distribution locations, mangrove shapes, and longitude and latitude coordinate information of each mangrove and mangrove area control point. The mangrove image needs to clearly reflect the outline, shape, color, longitude and latitude of the mangroves.

[0025] Step S12: obtaining measured parameters of the target mangrove area, wherein the measured parameters are data obtained by field measuring the mangroves in the target mangrove area in a field exploration manner.

[0026] During field measurements, this embodiment measures parameters such as the root, trunk, leaf shape, quantity, slope, etc. of a typical mangrove structure, so as to establish a correlation between the crown diameter reflected in the drone mangrove image and the roots, branches, trunks, and leaves, respectively, based on statistical results.

[0027] Step S2: determining the mangrove characteristic relationship of the target mangrove area according to the mangrove image and the measured parameters; the mangrove characteristic relationship is used to characterize the correlation between the crown diameter of the mangrove and the roots, branches and leaves, respectively.

[0028] In this embodiment, step S2 determines the mangrove characteristic relationship of the target mangrove area according to the mangrove image and the measured parameters, and specifically includes the following steps.

[0029] Step S21: determining the crown diameter of each mangrove tree in the mangrove forest image according to the mangrove forest image.

[0030] Step S22: According to the crown diameter of each mangrove in the mangrove forest image, a mathematical statistical method is used to determine the root length, root diameter, trunk length, trunk slope, trunk diameter, leaf shape, leaf number and leaf area of ​​the mangrove corresponding to the measured parameters.

[0031] Step S23, determining the mangrove characteristic relationship according to the crown diameter of each mangrove and the corresponding root length, root diameter, trunk length, trunk slope, trunk diameter, leaf shape, leaf number and leaf area.

[0032] This embodiment establishes a typical mangrove structure by measuring the three-dimensional structure of mangroves. The typical mangrove structure here refers to a mangrove with normal development that can represent the growth level of ordinary mangroves in the current mangrove area, and establishes the correlation between the crown diameter and the roots, branches and leaves. In the field survey, a sufficient number of typical mangrove structures are measured to obtain the height and width data of the typical mangrove structure as well as the scale, number, and appearance information of the roots, branches, and leaves. Combined with the plane scanning of the drone, the corresponding crown plane size is obtained. Through mathematical statistical methods, such as Fisher statistics, the most likely corresponding detailed data of a mangrove with a typical crown size is obtained to achieve the conversion from plane to three-dimensional. That is, for mangroves in any other area, as long as the two-dimensional plane mangrove image is used, the detailed data of the mangroves in the area can be obtained.

[0033] Step S3, calculating mangrove distribution parameters according to the mangrove image; the mangrove distribution parameters include mangrove distribution density, average crown area, average crown diameter and average mangrove spacing.

[0034] In this embodiment, step S3 calculates mangrove distribution parameters according to the mangrove image, and specifically includes the following steps.

[0035] Step S31, batch cropping the mangrove images to obtain a plurality of cropped pieces.

[0036] Step S32: performing coverage identification on each of the cut pieces to obtain the coverage corresponding to each of the cut pieces.

[0037] Step S33: Identify the number of mangroves on each of the cut pieces to obtain the number of mangroves corresponding to each of the cut pieces.

[0038] Step S34, calculating the mangrove distribution parameters according to the number of mangroves, the coverage, the height of the mangroves, and the width of the mangroves corresponding to each of the cut pieces.

[0039] In this embodiment, a software for identifying the coverage and quantity of mangroves is used. The software is made based on the Python language and mainly includes functions such as image import and batch cropping, batch recognition of the coverage of cut pieces, batch recognition of the number of mangroves with larger spacing, batch recognition of the number of mangroves with smaller spacing through pixel expansion, and splicing and reconstruction of cut pieces. Among them, the image import and batch cropping functions are to import mangrove images and crop them into several cut pieces, so as to obtain the local distribution information of the mangrove images. The smaller the cut pieces, the higher the accuracy. This can avoid the situation where the mangrove images are too large, resulting in long processing time or stuck and crashing. The functions of batch recognition of the coverage of cut pieces, batch recognition of the number of mangroves with larger spacing, and batch recognition of the number of mangroves with smaller spacing through pixel expansion are used to extract the crown coverage and mangrove quantity information of each cut piece. The cut piece splicing and reconstruction function can reassemble the cut pieces that have been covered and identified and marked into a high-precision and complete mangrove image. Specifically includes the following steps.

[0040] Step (1): Image import and batch cropping. The user uses the filedialog statement to implement the file dialog box to select the image file function. The software displays the imported image as a thumbnail and records its actual size. The user enters the size and step length of the cropping block (in pixels), uses the patchify statement to split the image into multiple small blocks, and saves each block as a separate image file named in the format of "patch_{i}_{j}.png", where i and j represent the row number and column number respectively.

[0041] Step (2): Cover recognition, including batch recognition of cut pieces. The purpose of the cover recognition function is to determine the plant cover by analyzing the number of green pixels in the image. Cover is expressed in the image as the percentage of the sum of plant pixels to all pixels in the area. NDI (Normalized Difference Index) is used as an indicator to distinguish between plants and non-plants. The calculation method is NDI = (GR) / (G + R), where G and R are the values ​​of the visible light green band and visible light red band, respectively. If NDI is greater than 0, it is considered a plant, otherwise it is a non-plant.

[0042] The software loads the images named "patch_{i}_{j}.png" in step (1) in sequence, calculates the number of green pixels in each image, and saves the result as an image highlighting the green plant area, storing it in a new folder with the original file name, and storing the number of green pixels and corresponding coverage data of each patch in an Excel table. The software can also calculate and identify the coverage of a single large image.

[0043] Step (3): Identification of the number of mangroves, including batch identification of the number of mangroves with larger spacing and batch identification of the number of mangroves with smaller spacing through pixel expansion. Through step (2), the green pixel area in the image is analyzed, and the contour (drawing the contour lines of the matrix) statement is used to extract the mangrove outline, calculate the center coordinates and radius of each mangrove, count the number of mangroves, generate an image marking the location of the mangroves, store it in a new folder with the original file name, and store the data in an Excel spreadsheet.

[0044] In view of the situation where the distance between mangroves is small and the crowns are difficult to distinguish, this embodiment adds a dilation operator Kernel, which first corrodes and then dilates the image to remove noise and small areas, thereby more accurately identifying the mangrove area. Users can flexibly adjust the kernel size (Kernel Size) according to the characteristics of the specific image to obtain the best processing effect. The processed image is stored in a new folder with the original file name.

[0045] Step (4): Reconstruction of stitching. Read the stitching pieces numbered by row and column in step (2) or step (3) in sequence, stitch the image blocks of each row horizontally, and then stitch all rows vertically into a complete image. The program saves the stitched complete image to the specified folder and displays a thumbnail for the user to preview.

[0046] In this embodiment, since the mangrove images taken by drones are usually large, the image processing and manual inspection of the recognition effect of large images are usually slow, and even jamming and freezing may occur. The purpose of cutting pieces is to process the larger mangrove images in the form of pieces, thereby improving processing efficiency and preventing jamming and freezing. Since it is necessary to determine the position of each piece on the complete image of the mangrove image, and the inspection and recognition effect is not convenient enough, this embodiment uses the method of splicing and reconstructing pieces to ensure the integrity of the process and to check whether the pieces are correct. The final effect is to accurately mark the position of each mangrove on the high-definition large picture of the original mangrove image, forming an image marked with the position of the mangrove that can be directly displayed, and the thumbnail can be directly popped up after the program runs.

[0047] Step (5): Data post-processing. The cover data and mangrove quantity data in steps (2) and (3) are post-processed to obtain mangrove distribution parameters such as mangrove distribution density, average crown area, average crown diameter, and average mangrove spacing, which are expressed as the following formula.

[0048] (1).

[0049] (2).

[0050] (3).

[0051] (4).

[0052] in, represents the mangrove distribution density of the patch, represents the number of mangroves, Indicates the actual site area corresponding to the cut piece. Indicates the height of the cut piece, which corresponds to the length of the actual site. Indicates the width of the cut piece, which corresponds to the width of the actual site. represents the average crown area, Indicates coverage, represents the average crown diameter, represents the average spacing between mangroves, that is, the average distance between two adjacent mangroves. Represents pi.

[0053] According to the correlation between the crown diameter obtained in step S2 and the roots, branches and leaves, the average crown diameter is determined. The relationship between the root and trunk is used to determine the characteristic diameter of the mangrove in formula (5): .

[0054] In this embodiment, the characteristic diameter of the mangrove Defined as the speed weight scale, the projected area of ​​the mangrove's frontal surface is adjusted according to the speed weight distributed along the mangrove height. The calculation formula is as follows.

[0055] (5).

[0056] in, is the characteristic diameter of mangroves, is the projected area of ​​the frontal surface, For water depth, is the vertical distance from the tree crown to the water surface, k is the wave number of the regular wave, is the plant height, i.e. the height of the mangrove, cosh is a hyperbolic function.

[0057] Step S4: Calculate the wave-breaking parameters according to the mangrove distribution parameters and the mangrove characteristic relationship. The wave-breaking parameters include the attenuation coefficient and drag force parameters .

[0058] When calculating the wave dissipation parameters in this embodiment, a physical model can be made according to the mangrove characteristics of the target mangrove area to conduct physical experiments. For example, a physical model of mangroves with different typical structures is made with a real mangrove model as a reference, and the attenuation coefficient is calculated through physical experiments. and drag force parameters , thus obtaining the attenuation coefficient by supplementing the physical experiment and drag force parameters In practical applications, it is also possible to first determine whether there is historical data related to the wave-breaking parameters of mangroves in the target mangrove area. These historical data are similar physical experimental data obtained in advance through physical experiments. These historical data can be used as references, and data comparison and other processing can also be performed on the basis of these historical data to update and obtain a more accurate attenuation coefficient. and drag force parameters .

[0059] Step S5, determining the wave height variation along the mangroves in the target mangrove area according to the wave-breaking parameters and the mangrove distribution parameters; the wave height variation is used to characterize the wave-breaking capacity of the mangroves in the target mangrove area.

[0060] In this embodiment, step S5 determines the change in wave height along the mangroves in the target mangrove area according to the wave-breaking parameters and the mangrove distribution parameters, and specifically includes the following steps.

[0061] Step S51: divide the target mangrove area into computational grids, and match the corresponding drag force parameters for each divided grid according to the mangrove distribution parameters and the wave dissipation parameters. .

[0062] Step S52: Drag force parameters matched according to each grid , and determine the boundary conditions in combination with known hydrodynamic parameters; the hydrodynamic parameters include the incident wave height, the incident wave root mean square height, the wave number of regular waves, and the wave number corresponding to the peak frequency before entering the mangrove forest.

[0063] Step S53: Match the drag force parameters of each grid , hydrodynamic parameters and boundary conditions are input into the two-dimensional mathematical model calculation software, and the wave height changes along the mangrove forest in the target mangrove area are output.

[0064] In this embodiment, the calculation grid of the mangrove coast is divided according to the mangrove distribution parameters obtained in step S3 and the attenuation coefficient obtained in step S4. and drag force parameters , matching the grid information. Among them, the computational grid of the mangrove coast is divided through mainstream software, such as mike (scene simulation software), openfoam (open source computational fluid dynamics software) and other software, and the division can also be completed through software such as matlab and python. Dividing the computational grid of the mangrove coast refers to dividing the calculation area of ​​the mangrove coast into multiple grids. The more grids are divided, the higher the accuracy of the calculation, and the more it can reflect the information contained in each point in the grid area. The grid area refers to the calculation area. The grid can cover the entire mangrove forest or only part of the mangrove forest. The grid points store information such as speed and pressure. It can be simply understood that each grid needs to be calculated. When all grid calculations are completed, the hydrodynamic conditions of the grid area can be obtained. Drag force parameters It is a calculated parameter. Each grid has a corresponding drag force parameter. The distribution parameters of mangroves have been obtained based on previous image processing. The distribution of detailed information can be inferred based on statistical methods. The attenuation coefficient of each mangrove has been determined by combining physical experiments and existing data. and drag force parameters , then as long as we know which mangrove the grid position corresponds to, we can know the drag force parameter corresponding to the grid .

[0065] In this embodiment, the attenuation coefficient and drag force parameters It is a parameter often used in mangrove wave-breaking calculations. Wave conditions include regular waves and irregular waves. Regular waves are an idealized wave waveform, usually a sine wave with a small amplitude in deep water. The characteristics of regular waves are that their waveforms and wave elements are the same in the wave train, and the wave surface can be expressed by a simple function. Irregular waves can be regarded as the superposition of multiple regular waves with different periods and amplitudes.

[0066] In this embodiment, when the wave condition is a regular wave condition, the calculation formula is as follows.

[0067] (6).

[0068] (7).

[0069] in, is the corresponding attenuation coefficient under regular wave conditions, is the drag force parameter, is the incident wave height before entering the mangrove forest, is the height of the transmitted wave at any point when the mangroves exist, where the incident wave refers to the wave before the seawater wave enters the mangroves, and the transmitted wave refers to the wave when the mangroves exist and the seawater wave has entered the mangroves and passed through the mangroves. For water depth, is the plant height, i.e. the height of the mangrove, is the characteristic diameter of mangroves, is the propagation distance of the wave in the mangrove area, is the average spacing between mangroves, is the wave number of the regular wave.

[0070] In this embodiment, a series of wave height meters arranged along the course can be used to measure wave data. A wave height meter, also known as a wave meter, is a marine hydrological instrument for measuring wave height, including an optical wave meter, an acceleration wave meter, a water pressure wave meter, an acoustic wave meter, an airborne height meter, etc. Among them, the optical wave meter is a telescope placed in a shore observation station, which determines the wave height, wave direction and period according to the beating of the anchor buoy in the water outside the shore. The acceleration wave meter is usually placed on the sea surface and measures waves using the acceleration principle. The water pressure wave meter is placed on the seabed and measures waves by sensing the change in the height of the water column above the instrument. The transceiver of the acoustic wave meter is placed at a certain depth underwater, and ultrasonic waves are emitted to the water surface using the principle of an echo sounder, and the wave height and period are measured from the amplitude and speed of the echo signal. The airborne height meter uses an aircraft to emit microwaves from the air to the sea surface, and the wave height is measured by the reflected wave. The microwave radiometer mounted on the satellite can also be used to synchronously measure wave data over a large area.

[0071] After obtaining the wave data, the attenuation coefficient is obtained by fitting according to formula (6): Formula (7) is the mathematically derived attenuation coefficient of the submerged wave height meter array under the action of regular waves: The calculation formula of drag force can be derived by substituting formula (6) into the left side of formula (7). .

[0072] In this embodiment, when the wave condition is an irregular wave condition, formulas (6) and (7) need to be rewritten as the following formulas.

[0073] (8).

[0074] (9).

[0075] in, is the corresponding attenuation coefficient under irregular wave conditions, is the drag force parameter, is the wave number corresponding to the peak frequency, and are the incident wave root mean square height and the transmitted wave root mean square height respectively. Substituting formula (8) into the left side of formula (9) can infer the drag force parameter .

[0076] In this embodiment, the drag force parameters corresponding to the model are calculated by measuring the wave parameters of mangrove physical models of different typical structures made with the real mangrove model as reference under various working conditions. , which can be directly applied to the construction of mathematical models. Divide the calculation area into grids, and match the drag force parameters of each grid according to the results of step S4. , combined with the known hydrodynamic parameters ( , , and ) Determine the boundary conditions, input the data into two-dimensional mathematical model calculation software, such as mike, openfoam and other software, and finally calculate the change of wave height along the mangroves, so as to achieve a refined assessment of the wave-breaking capacity of mangroves. The wave height propagated from the tail of the mangroves to the shore is obtained by calculation. Generally speaking, there are coastal embankments behind mangroves. The wave height threshold is stipulated in the design standards of coastal embankments and other specifications. If this wave height threshold is exceeded, the coastal embankment is considered unsafe. Mangroves can attenuate wave heights, but the wave-breaking capacity and wave-breaking effect of mangroves of different sizes and densities are different. By calculating the wave height change that characterizes the wave-breaking capacity of a certain design of mangroves, it can be evaluated whether the mangroves in the current state can attenuate waves to a safe wave height. If it can, it means that this design is feasible and the wave-breaking effect is considerable. If not, it is necessary to consider whether to increase the planting density of mangroves, widen the crown diameter of mangroves and other measures to improve the wave-breaking capacity and wave-breaking effect of mangroves.

[0077] This embodiment uses a faster and more convenient way to obtain relevant parameters of mangrove planar distribution, including mangrove coverage, number of mangroves, mangrove distribution density, average crown area, average crown diameter, and average spacing between mangroves, by identifying high-definition mangrove images, so as to further refine the parameter input in the two-dimensional mathematical model. By establishing the correlation between the crown diameter and the roots, branches, and leaves, the two-dimensional image is combined with the three-dimensional data, which can be used for the drag force parameter. Calculation and mathematical simulation. By establishing the drag force parameters The grid distribution is consistent with the actual distribution of mangroves, which further refines the parameter selection for mathematical simulation of mangrove wave dissipation.

[0078] This embodiment takes Kandelia candel as an example. Kandelia candel is a shrub or small tree of the Kandelia genus of the rhizophoraceae family. This embodiment uses Kandelia candel in mature stage and Kandelia candel in growing stage for comparative experiment to verify the drag force parameters of Kandelia candel in mature stage and Kandelia candel calculated by the technical solution of this embodiment. and attenuation coefficient Among them, serial number 1 is mature autumn candela, serial number 2 is growing autumn candela, Table 1 is the comparison of experimental results of mature autumn candela and growing autumn candela, and Table 2 is the experimental parameters used in the experiments of mature autumn candela and growing autumn candela.

[0079] Table 1 Comparison of experimental results of mature and growing Kandelia candel

[0080]

[0081] Table 2 Parameters and values ​​used in the comparative experiment between mature and growing stages of Kandelia candel

[0082]

[0083] It can be seen from Table 1 and Table 2 that the technical solution of this embodiment can accurately calculate the drag force parameters and attenuation coefficient , and the drag force parameters of mature Kandelia candel and attenuation coefficient It is higher than that of the growing stage autumn Kandelia, indicating that the wave-breaking ability and wave-breaking effect of the mature stage autumn Kandelia are stronger than those of the growing stage autumn Kandelia.

[0084] In an exemplary embodiment, a two-dimensional mangrove coast plane parameter collection and calculation device is also provided. The two-dimensional mangrove coast plane parameter collection and calculation device includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, the steps of the above-mentioned two-dimensional mangrove coast plane parameter collection and calculation method are implemented.

[0085] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0086] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A two-dimensional mangrove coast plane parameter collection and calculation method, characterized in that: The two-dimensional mangrove coast plane parameter acquisition and calculation method includes: Obtaining a mangrove image and measured parameters of a target mangrove area; the mangrove image is a two-dimensional mangrove coast plane image obtained directly above the target mangrove area, and the measured parameters are data obtained by field measurement of mangroves in the target mangrove area, and the measured parameters include the number of mangroves, root length, root diameter, trunk length, trunk slope, trunk diameter, leaf shape, leaf number, and leaf area; Determining a mangrove characteristic relationship of the target mangrove forest area according to the mangrove forest image and the measured parameters; the mangrove characteristic relationship is used to characterize the correlation between the crown diameter of the mangrove and the root, branch and leaf respectively; Calculating mangrove distribution parameters according to the mangrove image; the mangrove distribution parameters include mangrove distribution density, average crown area, average crown diameter and average mangrove spacing; Calculating mangrove distribution parameters according to the mangrove image includes: Batch cropping the mangrove images to obtain a number of cropped pieces; Performing coverage identification on each of the cut pieces to obtain the coverage corresponding to each of the cut pieces; Identify the number of mangroves for each of the cut pieces to obtain the number of mangroves corresponding to each of the cut pieces; The mangrove distribution parameters are calculated according to the number of mangroves, the coverage, the height of the mangroves, and the width of the mangroves corresponding to each of the mangrove slices, specifically including: The following formula is used to calculate the mangrove distribution density: ； in, represents the mangrove distribution density of the patch, represents the number of mangroves, Indicates the actual site area corresponding to the cut piece. Indicates the height of the cut piece. Indicates the width of the cut piece; The average crown area is calculated using the following formula: ； in, represents the average crown area, Indicates coverage; The average crown diameter is calculated using the following formula: ； in, represents the average crown diameter; is the ratio of pi; The average spacing of mangroves is calculated using the following formula: ； in, represents the average spacing of mangroves; Calculating wave-breaking parameters according to the mangrove distribution parameters and the mangrove characteristic relationship; the wave-breaking parameters include an attenuation coefficient and a drag force parameter; The wave height variation along the mangroves in the target mangrove area is determined according to the wave-breaking parameters and the mangrove distribution parameters; the wave height variation is used to characterize the wave-breaking capacity of the mangroves in the target mangrove area.

2. The two-dimensional mangrove coast plane parameter acquisition and calculation method according to claim 1 is characterized in that: Obtain mangrove images and measured parameters in the target mangrove area, including: Acquire a mangrove image of a target mangrove area, wherein the mangrove image is an image obtained by plane mapping the mangroves in the target mangrove area using a drone; The measured parameters of the target mangrove area are obtained, where the measured parameters are data obtained by field measuring the mangroves in the target mangrove area in a field exploration manner.

3. The two-dimensional mangrove coast plane parameter acquisition and calculation method according to claim 1 is characterized in that: Determining the mangrove characteristic relationship of the target mangrove area according to the mangrove image and the measured parameters specifically includes: Determine, according to the mangrove forest image, the crown diameter of each mangrove tree in the mangrove forest image; According to the crown diameter of each mangrove in the mangrove forest image, a mathematical statistical method is used to determine the root length, root diameter, trunk length, trunk slope, trunk diameter, leaf shape, leaf number and leaf area of ​​the mangrove corresponding to the measured parameters; The mangrove characteristic relationship is determined based on the crown diameter of each mangrove and the corresponding root length, root diameter, trunk length, trunk slope, trunk diameter, leaf shape, leaf number and leaf area.

4. The two-dimensional mangrove coast plane parameter acquisition and calculation method according to claim 1 is characterized in that: When the wave condition is a regular wave condition, the wave elimination parameter is calculated using the following formula: ； ； in, is the corresponding attenuation coefficient under regular wave conditions, is the drag force parameter, is the incident wave height before entering the mangrove forest, is the height of the transmitted wave at any point when the mangrove exists, For water depth, is the plant height, is the characteristic diameter of mangroves, is the propagation distance of the wave in the mangrove area, is the average spacing between mangroves, is the wave number of the regular wave, is the ratio of pi; When the wave condition is irregular, the wave elimination parameters are calculated using the following formula: ； ； in, is the corresponding attenuation coefficient under irregular wave conditions, is the wave number corresponding to the peak frequency, and are the RMS height of the incident wave and the RMS height of the transmitted wave, respectively.

5. The two-dimensional mangrove coast plane parameter acquisition and calculation method according to claim 1 is characterized in that: Determining the wave height change along the mangrove forest in the target mangrove forest area according to the wave dissipation parameter and the mangrove distribution parameter, specifically includes: Divide the target mangrove area into computational grids, and match corresponding drag force parameters for each divided grid according to the mangrove distribution parameters and the wave-breaking parameters; Determine the boundary conditions according to the drag force parameters matched by each grid and in combination with known hydrodynamic parameters; the hydrodynamic parameters include the incident wave height, the incident wave root mean square wave height, the wave number of regular waves and the wave number corresponding to the peak frequency before entering the mangrove forest; The drag force parameters, hydrodynamic parameters and boundary conditions matched for each grid are input into the two-dimensional mathematical model calculation software, and the wave height changes along the mangrove forest in the target mangrove forest area are output.

6. A two-dimensional mangrove coast plane parameter acquisition and calculation device, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the two-dimensional mangrove coast plane parameter acquisition and calculation method according to any one of claims 1 to 5.

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