A large-scale wave flume automatic scanning device and method for scouring and silting terrain

Abstract

The invention relates to the field of marine engineering technology, and discloses an automatic scanning device and method for scouring and silting terrain of a large-scale wave flume. The method comprises: scanning the bed of a large-scale wave flume, reconstructing the bed of the large-scale wave flume in three dimensions to obtain three-dimensional point cloud data, converting the coordinate system of the three-dimensional point cloud data into a world coordinate system, and obtaining the height data of the bed of the large-scale wave flume at each time point according to the world coordinate system; obtaining the curvature of the bed according to the abscissa, ordinate, and bed height in the world coordinate system; determining the scouring and silting area according to the curvature; determining several time intervals, and calculating the average scouring and silting depth of the scouring and silting area in each time interval in the past; accumulating the average scouring and silting depth to obtain the comprehensive scouring and silting depth. Specific and accurate depth data is obtained, and data support is provided for subsequent early warning according to the depth data and the overall change trend of the wound surface.

Description

Technical Field

[0001] The invention relates to the technical field of marine engineering, and in particular to a device and method for automatically scanning scouring and silting terrain in a large-scale wave flume. Background Art

[0002] In marine engineering and civil engineering, stability monitoring of coastline protection structures is a vital task. With the increase of coastal development activities, protecting the coastline from erosion has become an urgent problem to be solved. To this end, researchers often use large-scale wave flumes to simulate the effects of waves in natural environments in order to study the performance of protection structures under different conditions.

[0003] Traditional monitoring methods usually rely on manual observation or manual measurement, which is not only time-consuming and labor-intensive, but also difficult to achieve high-frequency real-time monitoring. In addition, manual observation often fails to capture subtle changes, especially for small deformations at the reinforcement site or subtle movements of sediments. Traditional monitoring methods are difficult to provide sufficient accuracy. In recent years, with the development of photogrammetry and three-dimensional reconstruction technology, new methods have emerged that use professional underwater measurement cameras for automated monitoring. These methods record the changes in the caisson embankment reinforcement in real time by deploying photogrammetry equipment in a large-scale wave flume, and obtain detailed topographic information through three-dimensional reconstruction technology. Although three-dimensional reconstruction technology can provide detailed bed morphology, it is difficult to directly obtain specific scouring and silting depth information based solely on three-dimensional reconstruction data. Further time series analysis is usually required to identify the changing trend of the scouring and silting area, but existing technologies are not perfect in this regard and lack data support. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a large-scale wave flume scouring and silting terrain automatic scanning device and method to realize the calculation of scouring and silting depth.

[0005] The present invention provides a method for automatically scanning and measuring scouring and silting terrain in a large-scale wave flume, comprising:

[0006] Step 1: Place the photogrammetric equipment on the side wall of the large-scale wave flume close to the caisson dike, and partially immerse the photogrammetric equipment below the liquid level, scan the bed surface of the large-scale wave flume, and record a video of the scouring and silting process of the caisson dike;

[0007] Step 2: placing a calibration target on the bed of a large-scale wave tank, and using a photogrammetric device to capture an image of the calibration target to calibrate the photogrammetric device, thereby obtaining internal and external parameters of the photogrammetric device;

[0008] Step 3, based on the internal and external parameters of the photogrammetry equipment, the bed surface of the large-scale wave tank is three-dimensionally reconstructed to obtain three-dimensional point cloud data, and the coordinate system of the three-dimensional point cloud data is converted into a world coordinate system to obtain the height data of the bed surface of the large-scale wave tank at each time point; the coordinate point of the world coordinate system is (x, y, z), x represents the abscissa of the world coordinate system, y represents the ordinate of the world coordinate system, and z represents the height of the bed surface under the (x, y) coordinate in the world coordinate system;

[0009] Step 4, obtaining the curvature of the bed surface according to the abscissa, ordinate, and bed surface height in the world coordinate system;

[0010] Step 5, determining the scouring and silting area according to the curvature;

[0011] Step 6, determining the time interval, and calculating the average scouring and silting depth of the scouring and silting area in each past time interval;

[0012] Step 7, accumulating the average scouring and silting depth to obtain the comprehensive scouring and silting depth.

[0013] Furthermore, the curvature of the bed surface is obtained according to the abscissa, ordinate, and bed surface height in the world coordinate system, which specifically includes the following steps:

[0014] Step 41, preprocessing the coordinate points in the world coordinate system to obtain preprocessed coordinate points;

[0015] Step 42, selecting a target point to be measured from the preprocessed coordinate points, and selecting preprocessed coordinate points of different scales around the target point to be measured as adjacent coordinate points;

[0016] Step 43, fitting the target point to be measured and the adjacent coordinate points of different scales into local surfaces of different scales;

[0017] Step 44, the curvature of the local surface of different scales is calculated according to the abscissa, ordinate and bed height in the world coordinate system.

[0018] Furthermore, the calculation formula of the curvature is:

[0019] ;

[0020] In the formula, in the formula, Represents the bed surface The curvature of the coordinate point, represents the adjustment factor, represents the second-order partial derivative of the bed height on the horizontal axis, represents the second-order partial derivative of the bed height on the ordinate, represents the third-order partial derivative of the bed height on the horizontal axis, Represents the third-order partial derivative of the bed height on the ordinate.

[0021] Further, determining the scouring and silting area according to the curvature specifically includes the following steps:

[0022] Step 51, obtaining a threshold value;

[0023] Step 52, comparing the curvature of the local surface with a threshold value, when the curvature of the local surface is greater than the threshold value, the target center point of the current local surface is an erosion and siltation edge point; when the curvature of the local surface is less than or equal to the threshold value, the target center point of the current local surface is a non-erosion and siltation edge point;

[0024] Step 53, obtaining the scouring and silting area according to all scouring and silting edge points.

[0025] Furthermore, the calculation formula of the average scouring and silting depth is:

[0026] ;

[0027] represents the average scouring depth of the scouring area at the current time point t, T represents the time interval, represents the weight function, Represents a point in time in the past Bed height data, Represents the initial height data of the bed surface at the initial moment, Represents a point in time in the past Do calculus.

[0028] Furthermore, the weight function is:

[0029] ;

[0030] In the formula, Represents a point in time in the past The weight function of Represents the standard deviation of the time difference between the past time point and the current time point within the time interval, t represents the current time point, Represents a point in time in the past.

[0031] Furthermore, the calculation formula of the comprehensive scouring and silting depth is:

[0032] ;

[0033] Represents the comprehensive scouring depth of the scouring area, represents the average scouring and silting depth at the i-th time point, and n represents the maximum time point of the scouring and silting process.

[0034] Furthermore, historical curvature in historical data is obtained, historical abnormal curvature is obtained by analyzing the historical curvature, and a threshold is obtained according to the historical abnormal curvature.

[0035] Furthermore, the maximum historical curvature among the historical abnormal curvatures is used as a threshold.

[0036] This embodiment also discloses a large-scale wave flume scouring and silting terrain automatic scanning device, including the following modules:

[0037] Scanning module: used to place the photogrammetric equipment on the side wall of the large-scale wave flume close to the caisson dike, and partially immerse the photogrammetric equipment below the liquid level to scan the bed surface of the large-scale wave flume and record the video of the scouring and silting process of the caisson dike;

[0038] Calibration module: connected to the scanning module, used to place a calibration target on the bed of a large-scale wave tank. The photogrammetric device captures the calibration target image to calibrate the photogrammetric device and obtain the internal and external parameters of the photogrammetric device.

[0039] 3D reconstruction module: connected with the calibration module, used to perform 3D reconstruction on the bed surface of the large-scale wave tank according to the internal and external parameters of the photogrammetry equipment, obtain 3D point cloud data, convert the coordinates of the 3D point cloud data into the coordinates of the world coordinate system, and obtain the height data of the bed surface of the large-scale wave tank at each time point;

[0040] Curvature calculation module: connected with the 3D reconstruction module, used to obtain the curvature of the bed surface according to the horizontal coordinate, vertical coordinate and bed surface height in the world coordinate system;

[0041] Scouring and silting area determination module: connected to the curvature calculation module, used to determine the scouring and silting area according to the curvature;

[0042] Average scouring and silting depth calculation module: connected with the scouring and silting area determination module, used to determine the time interval and calculate the average scouring and silting depth of the scouring and silting area in each past time interval;

[0043] Comprehensive scouring and silting depth calculation module: connected with the average scouring and silting depth calculation module, used to accumulate the average scouring and silting depth to obtain the comprehensive scouring and silting depth.

[0044] The embodiments of the present invention have the following technical effects:

[0045] The present invention uses the existing technology to perform three-dimensional reconstruction of the bed surface, calculates the curvature using coordinate points and riverbed height data, and also calculates the average scouring and silting depth in each time interval, and obtains the comprehensive scouring and silting depth based on the average scouring and silting depth. Through such a calculation method, specific and accurate depth data can be obtained, and according to the depth data and the overall change trend of the wound surface, data support is provided for subsequent early warning, thereby improving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0047] Figure 1 This is a flow chart of a method for automatically scanning scouring and silting terrain in a large-scale wave flume provided by an embodiment of the present invention;

[0048] Figure 2 It is a structural schematic diagram of a method for automatically scanning scouring and silting terrain in a large-scale wave flume provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0050] A caisson dam is reinforced in the width direction of the large-scale wave flume, and both ends of the caisson dam are sealed and connected to the side walls of the large-scale wave flume. The structure of the caisson dam is optional and can be a square or arched structure. The photogrammetry equipment monitors the scouring and silting process between the caisson dam and the bottom of the large-scale wave flume. During the wave crossing process, the waves continuously impact the caisson dam and the reinforced parts of the large-scale wave flume. This embodiment calculates the scouring and silting depth to provide data support for the later early warning mechanism, effectively monitor the stability of the caisson dam, prevent potential risks, and take timely measures to ensure the safety and durability of the structure.

[0051] Figure 1 Flow chart of a method for automatically scanning scouring and silting terrain in a large-scale wave flume provided by an embodiment of the present invention. Figure 1 , specifically including:

[0052] Step 1: Place the photogrammetric equipment on the side wall of the large-scale wave flume close to the caisson dike, and partially immerse the photogrammetric equipment below the liquid level to scan the bed surface of the large-scale wave flume and record a video of the scouring and silting process of the caisson dike.

[0053] This embodiment uses a professional underwater measurement camera. A stainless steel bracket is installed on the side wall of a large-scale wave tank, and the camera is fixed to the bracket by screws. An external power supply or battery pack is connected via a cable to ensure that the device can work continuously. The photogrammetry device is started and set to continuous recording mode. The external display screen is connected via a cable to monitor the shooting effect in real time. The video data is transmitted to an external storage device in real time via the cable and backed up.

[0054] Step 2: Place a calibration target on the bed of a large-scale wave tank, and use a photogrammetric device to capture an image of the calibration target to calibrate the photogrammetric device, thereby obtaining internal and external parameters of the photogrammetric device.

[0055] In step 2, the photogrammetric equipment is calibrated using a calibration target in order to obtain the intrinsic and extrinsic parameters of the photogrammetric equipment, thereby ensuring the accuracy of subsequent 3D reconstruction. The calibration target is usually an object with known geometric shape and size, which is used to calibrate the photogrammetric equipment. Commonly used calibration targets include:

[0056] Chessboard: It is composed of black and white squares, which makes it easy to detect the corner position;

[0057] Dot array: A grid composed of dots, which can also be used to detect feature points;

[0058] Barcode: A barcode with a specific encoding that can provide additional information.

[0059] Place any of the above calibration targets on the bed of a large-scale wave tank, photograph the calibration target from multiple angles and distances to cover the entire field of view of the photogrammetric equipment, and place some obvious marking points on the calibration target to facilitate positioning during later image processing.

[0060] Use photogrammetry equipment to capture images of the calibration target from different angles and distances, ensure that the calibration target in each image is clearly visible, without occlusion or blur, pre-process the captured images, including denoising, contrast enhancement, etc., to improve the detection accuracy of feature points, use image processing algorithms to extract the positions of feature points, and use calibration algorithms to calculate the internal parameters of the device. Internal parameters include: focal length, principal point, pixel distortion coefficient, etc., and external parameters include rotation matrix and translation vector.

[0061] Step 3, reconstruct the bed surface of the large-scale wave tank in three dimensions according to the internal and external parameters of the photogrammetry equipment to obtain three-dimensional point cloud data, convert the coordinate system of the three-dimensional point cloud data into a world coordinate system, and obtain the height data of the bed surface of the large-scale wave tank at each time point.

[0062] The process of 3D reconstruction is a conventional technical means. The images taken by the device are loaded, and the feature points in the image are extracted using the feature detection algorithm. Feature matching is performed on multiple images to find the feature points in the image. The feature points and their matching relationships are used to generate sparse point cloud data. Multiple images are used for stereo matching to generate dense point cloud data. The two-dimensional feature points are mapped to the three-dimensional space using the triangulation algorithm to obtain three-dimensional point cloud data. Coordinate system conversion is also a mature technology, which converts the pixel coordinate system in the image into the camera coordinate system, and the camera coordinate system into the world coordinate system.

[0063] The coordinate point of the world coordinate system is (x, y, z), where x represents the horizontal coordinate of the world coordinate system, y represents the vertical coordinate of the world coordinate system, and z represents the height of the bed surface under the (x, y) coordinate in the world coordinate system.

[0064] Step 4, obtaining the curvature of the bed surface according to the abscissa, ordinate, and bed surface height in the world coordinate system;

[0065] Step 41, preprocessing the coordinate points in the world coordinate system to obtain preprocessed coordinate points.

[0066] Step 42 , selecting a target point to be measured from the preprocessed coordinate points, and selecting preprocessed coordinate points of different scales around the target point to be measured as neighboring coordinate points.

[0067] The 3D point cloud data is divided into multiple grids, and the center point of each grid is used as the target point to be measured. For the target point to be measured, the coordinate points within different diameter ranges are selected as the adjacent coordinate points.

[0068] Selecting neighboring coordinate points at different scales is crucial for curvature calculation, because different scales will affect the fitting accuracy of the local surface and the accuracy of the curvature.

[0069] Selecting a smaller number of neighboring coordinate points (such as points inside a circle with a smaller radius) is suitable for capturing local details. Neighboring coordinate points at a small scale can better reflect subtle changes on the surface.

[0070] Selecting a larger number of neighboring coordinate points (such as points within a circle with a larger radius) is suitable for capturing macro trends. Neighboring coordinate points at a large scale can better reflect the overall trend.

[0071] Therefore, this embodiment selects pre-processed coordinate points of different scales as adjacent coordinate points, which can not only observe subtle changes in the surface, but also see the overall trend of the surface. Multi-scale analysis is a powerful tool that can take into account local and global information while maintaining high accuracy, making the scouring and silting monitoring system more practical. Through this method, the changes in the bed surface can be more comprehensively understood, providing more reliable data support, and thus improving the design and maintenance strategy of the reinforcement structure.

[0072] Step 43: Fit the target point to be measured and the adjacent coordinate points of different scales into local surfaces of different scales.

[0073] The adjacent coordinate points of different scales and the target point to be measured are fitted into local surfaces of different scales. The fitting of the local surface can be obtained by the least square method in the prior art.

[0074] Step 44, the curvature of the local surface of different scales is calculated according to the abscissa, ordinate and bed height in the world coordinate system.

[0075] The calculation formula of the curvature is:

[0076] ;

[0077] In the formula, Represents the bed surface The curvature of the coordinate point, represents the adjustment factor, represents the second-order partial derivative of the bed height on the horizontal axis, Get the curvature of the bed surface in the horizontal direction, represents the second-order partial derivative of the bed height on the ordinate, Get the curvature of the bed surface in the ordinate direction, represents the third-order partial derivative of the bed height on the horizontal axis, Get the bending change rate of the bed surface in the horizontal axis direction, represents the third-order partial derivative of the bed height on the ordinate, Get the bending change rate of the bed surface in the ordinate direction.

[0078] This embodiment simultaneously considers the curvature degree and curvature change rate of the bed surface in the horizontal and vertical directions to calculate the curvature, measures the change of the local surface and its curvature speed, and improves the calculation accuracy of the curvature.

[0079] In mathematics, curvature is a concept used to measure the degree of curvature of a curve. For a curve in two-dimensional space, curvature can be defined by calculating the rate of change of the tangent direction at a point on the curve. In three-dimensional space, curvature usually refers to the rate of change of the normal vector at a point on the surface. In this embodiment, the curvature of the bed surface is calculated, which is a two-dimensional surface, so only two dimensions need to be considered.

[0080] Step 5, determining the scouring and silting area according to the curvature;

[0081] Step 51, obtaining a threshold value;

[0082] Obtain historical curvatures from historical data, analyze the historical curvatures to obtain historical abnormal curvatures, obtain thresholds based on the historical abnormal curvatures, and use the maximum historical curvature in the historical abnormal curvatures as the threshold.

[0083] For each historical curvature calculated at a historical time point, the mean and standard deviation are calculated. Three times the standard deviation is used as the identification standard for historical abnormal curvature, and the historical curvature with a deviation between any two standard deviations greater than three times the standard deviation is used as the historical abnormal curvature. According to this step, the historical abnormal curvature is identified, and the maximum historical curvature among the historical abnormal curvatures is used as the threshold.

[0084] Step 52, comparing the curvature of the local surface with a threshold value, when the curvature of the local surface is greater than the threshold value, the target center point of the current local surface is an erosion and siltation edge point; when the curvature of the local surface is less than or equal to the threshold value, the target center point of the current local surface is a non-erosion and siltation edge point;

[0085] Step 53, obtaining the scouring and silting area according to all scouring and silting edge points.

[0086] Step 6, determine the time interval, and calculate the average scouring and silting depth of the scouring and silting area in each past time interval.

[0087] The determined time interval means that the average scouring and silting depth is calculated once in a time interval. In other words, when calculating the scouring and silting in the scouring and silting area at each time point, the average scouring and silting depth generated in the time interval before the current time point should be calculated first. Reducing the scouring and silting fluctuations in the time interval while maintaining the same frequency to observe the scouring and silting changes will help understand the scouring and silting phenomenon and provide a scientific basis.

[0088] The calculation formula of the average scouring depth is:

[0089] ;

[0090] represents the average scouring depth of the scouring area at the current time point t, T represents the time interval, represents the weight function, Represents a point in time in the past Bed height data, Represents the initial height data of the bed surface at the initial moment, Represents a point in time in the past Do calculus.

[0091] The weight function is:

[0092] ;

[0093] In the formula, Represents a point in time in the past The weight function of Represents the standard deviation of the time difference between the past time point and the current time point within the time interval, t represents the current time point, Represents a point in time in the past.

[0094] The weight function emphasizes the importance of data that is more relevant to the current time point by assigning different weights to different data points. When calculating the average scour depth, the most recent data points (data close to the current time point) are generally considered to be more reflective of the current state and therefore have a greater weight in the calculation. The weight function can help achieve this, making the most recent data points have a greater impact on the results.

[0095] Step 7, accumulating the average scouring and silting depth to obtain the comprehensive scouring and silting depth.

[0096] The calculation formula of the comprehensive scouring and silting depth is:

[0097] ;

[0098] Represents the comprehensive scouring depth of the scouring area, represents the average scouring and silting depth at the i-th time point, and n represents the maximum time point of the scouring and silting process.

[0099] This embodiment also provides a large-scale wave flume scouring and silting terrain automatic scanning device, including the following modules:

[0100] Scanning module: used to place the photogrammetric equipment on the side wall of the large-scale wave flume close to the caisson dike, and partially immerse the photogrammetric equipment below the liquid level to scan the bed surface of the large-scale wave flume and record the video of the scouring and silting process of the caisson dike;

[0101] Calibration module: connected to the scanning module, used to place a calibration target on the bed of a large-scale wave tank. The photogrammetric device captures the calibration target image to calibrate the photogrammetric device and obtain the internal and external parameters of the photogrammetric device.

[0102] 3D reconstruction module: connected with the calibration module, used to perform 3D reconstruction on the bed surface of the large-scale wave tank according to the internal and external parameters of the photogrammetry equipment, obtain 3D point cloud data, convert the coordinate system of the 3D point cloud data into the world coordinate system, and obtain the height data of the bed surface of the large-scale wave tank at each time point;

[0103] Curvature calculation module: connected with the 3D reconstruction module, used to obtain the curvature of the bed surface according to the horizontal coordinate, vertical coordinate and bed surface height in the world coordinate system;

[0104] Scouring and silting area determination module: connected to the curvature calculation module, used to determine the scouring and silting area according to the curvature;

[0105] Average scouring and silting depth calculation module: connected with the scouring and silting area determination module, used to determine the time interval and calculate the average scouring and silting depth of the scouring and silting area in each past time interval;

[0106] Comprehensive scouring and silting depth calculation module: connected with the average scouring and silting depth calculation module, used to accumulate the average scouring and silting depth to obtain the comprehensive scouring and silting depth.

[0107] This embodiment provides an electronic device, including one or more processors and a memory.

[0108] The processor may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0109] The memory may include one or more computer program products, and the computer program product may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory (cache), etc. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor may run the program instructions to implement a large-scale wave flume scouring and silting terrain automatic scanning method and / or other desired functions of any embodiment of the present application described above. Various contents such as initial external parameters, thresholds, etc. may also be stored in the computer-readable storage medium.

[0110] In one example, the electronic device may further include: an input device and an output device, and these components are interconnected through a bus system and / or other forms of connection mechanisms (not shown). The input device may include, for example, a keyboard, a mouse, etc. The output device may output various information to the outside, including early warning information, braking force, etc. The output device may include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto, etc.

[0111] In addition, the electronic device may further include any other appropriate components according to specific application scenarios.

[0112] In addition to the above-mentioned methods and devices, an embodiment of the present application may also be a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to execute the steps of a method for automatically scanning the scouring and silting terrain of a large-scale wave flume provided in any embodiment of the present application.

[0113] The computer program product may be written in any combination of one or more programming languages ​​to write program codes for performing the operations of the embodiments of the present application, including object-oriented programming languages, such as Java, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as an independent software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0114] In addition, an embodiment of the present application may also be a computer-readable storage medium on which computer program instructions are stored. When the computer program instructions are executed by a processor, the processor executes the steps of a method for automatically scanning the scouring and silting terrain of a large-scale wave flume provided in any embodiment of the present application.

[0115] The computer readable storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can include, for example, but is not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0116] It should be noted that the terms used in the present invention are only for describing specific embodiments, rather than limiting the scope of the present application. As shown in the present specification, unless the context clearly indicates an exception, the words "one", "a", "a kind of" and / or "the" do not specifically refer to the singular, but may also include the plural. The terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method or device. In the absence of more restrictions, the elements defined by the sentence "include one..." do not exclude the presence of other identical elements in the process, method or device including the elements.

[0117] It should also be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A method for automatically scanning the scouring and silting terrain of a large-scale wave flume, characterized in that: include: Step 1: Place the photogrammetric equipment on the side wall of the large-scale wave flume close to the caisson dike, and partially immerse the photogrammetric equipment below the liquid level, scan the bed surface of the large-scale wave flume, and record a video of the scouring and silting process of the caisson dike; Step 2: placing a calibration target on the bed of a large-scale wave tank, and using a photogrammetric device to capture an image of the calibration target to calibrate the photogrammetric device, thereby obtaining internal and external parameters of the photogrammetric device; Step 3, three-dimensionally reconstruct the bed surface of the large-scale wave tank according to the internal parameters and external parameters of the photogrammetry equipment to obtain three-dimensional point cloud data, convert the coordinate system of the three-dimensional point cloud data into a world coordinate system, and obtain the height data of the bed surface of the large-scale wave tank at each time point according to the world coordinate system; the coordinate point of the world coordinate system is (x, y, z), x represents the abscissa of the world coordinate system, y represents the ordinate of the world coordinate system, and z represents the height of the bed surface under the (x, y) coordinate in the world coordinate system; Step 4, obtaining the curvature of the bed surface according to the abscissa, ordinate, and bed surface height in the world coordinate system; Step 5, determining the scouring and silting area according to the curvature; Step 6, determining the time interval, and calculating the average scouring and silting depth of the scouring and silting area in each past time interval; Step 7, accumulating the average scouring and silting depth to obtain the comprehensive scouring and silting depth.

2. The automatic scanning method for scouring and silting terrain of a large-scale wave flume according to claim 1 is characterized in that: According to the abscissa, ordinate and bed height in the world coordinate system, the curvature of the bed surface is obtained, which specifically includes the following steps: Step 41, preprocessing the coordinate points in the world coordinate system to obtain preprocessed coordinate points; Step 42, selecting a target point to be measured from the preprocessed coordinate points, and selecting preprocessed coordinate points of different scales around the target point to be measured as adjacent coordinate points; Step 43, fitting the target point to be measured and the adjacent coordinate points of different scales into local surfaces of different scales; Step 44, the curvature of the local surface of different scales is calculated according to the abscissa, ordinate and bed height in the world coordinate system.

3. The automatic scanning method for scouring and silting terrain of a large-scale wave flume according to claim 2 is characterized in that: The calculation formula of the curvature is: ； In the formula, Represents the bed surface The curvature of the coordinate point, represents the adjustment factor, represents the second-order partial derivative of the bed height on the horizontal axis, represents the second-order partial derivative of the bed height on the ordinate, represents the third-order partial derivative of the bed height on the horizontal axis, Represents the third-order partial derivative of the bed height on the ordinate.

4. The method for automatically scanning the scouring and silting terrain of a large-scale wave flume according to claim 1 is characterized in that: Determining the scouring and silting area based on the curvature includes the following steps: Step 51, obtaining a threshold value; Step 52, comparing the curvature of the local surface with a threshold value, when the curvature of the local surface is greater than the threshold value, the target center point of the current local surface is an erosion and siltation edge point; when the curvature of the local surface is less than or equal to the threshold value, the target center point of the current local surface is a non-erosion and siltation edge point; Step 53, obtaining the scouring and silting area according to all scouring and silting edge points.

5. The method for automatically scanning the scouring and silting terrain of a large-scale wave flume according to claim 1 is characterized in that: The calculation formula of the average scouring depth is: ； represents the average scouring depth of the scouring area at the current time point t, T represents the time interval, represents the weight function, Represents a point in time in the past Bed height data, Represents the initial height data of the bed surface at the initial moment, Represents a point in time in the past Do calculus.

6. The method for automatically scanning the scouring and silting terrain of a large-scale wave flume according to claim 5 is characterized in that: The weight function is: ； In the formula, Represents a point in time in the past The weight function of Represents the standard deviation of the time difference between the past time point and the current time point within the time interval, t represents the current time point, Represents a point in time in the past.

7. The method for automatically scanning the scouring and silting terrain of a large-scale wave flume according to claim 6 is characterized in that: The calculation formula of the comprehensive scouring and silting depth is: ； Represents the comprehensive scouring depth of the scouring area, represents the average scouring and silting depth at the i-th time point, and n represents the maximum time point of the scouring and silting process.

8. The method for automatically scanning the scouring and silting terrain of a large-scale wave flume according to claim 4 is characterized in that: The historical curvature in the historical data is obtained, the historical abnormal curvature is analyzed to obtain the historical abnormal curvature, and the threshold is obtained according to the historical abnormal curvature.

9. The automatic scanning method for scouring and silting terrain of a large-scale wave flume according to claim 8 is characterized in that: The maximum historical curvature among the historical abnormal curvatures is used as the threshold.

10. An automatic scanning device for scouring and silting terrain in a large-scale wave flume, used to execute the automatic scanning method for scouring and silting terrain in a large-scale wave flume according to any one of claims 1 to 9, characterized in that: Includes the following modules: Scanning module: used to place the photogrammetric equipment on the side wall of the large-scale wave flume close to the caisson dike, and partially immerse the photogrammetric equipment below the liquid level to scan the bed surface of the large-scale wave flume and record the video of the scouring and silting process of the caisson dike; Calibration module: connected to the scanning module, used to place a calibration target on the bed of a large-scale wave tank. The photogrammetric device takes an image of the calibration target to calibrate the device and obtain the internal and external parameters of the photogrammetric device. 3D reconstruction module: connected with the calibration module, used to perform 3D reconstruction on the bed surface of the large-scale wave tank according to the internal and external parameters of the photogrammetry equipment, obtain 3D point cloud data, convert the coordinate system of the 3D point cloud data into the world coordinate system, and obtain the height data of the bed surface of the large-scale wave tank at each time point according to the world coordinate system; Curvature calculation module: connected with the 3D reconstruction module, used to obtain the curvature of the bed surface according to the horizontal coordinate, vertical coordinate and bed surface height in the world coordinate system; Scouring and silting area determination module: connected to the curvature calculation module, used to determine the scouring and silting area according to the curvature; Average scouring and silting depth calculation module: connected with the scouring and silting area determination module, used to determine the time interval and calculate the average scouring and silting depth of the scouring and silting area in each past time interval; Comprehensive scouring and silting depth calculation module: connected with the average scouring and silting depth calculation module, used to accumulate the average scouring and silting depth to obtain the comprehensive scouring and silting depth.

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