An underwater crack sonar image simulation method, a storage medium and an equipment

Abstract

The application discloses an underwater crack sonar image simulation method, a storage medium and equipment, crack regions of a binary graph in optical crack data are migrated to a target model of a sonar system for observation, crack sonar images under different simulation parameters are obtained based on a sonar ray tracing principle, and a typical acoustic atlas is provided for detection of underwater cracks by using a sonar device, so that the problem that various forms of underwater cracks lack typical expressions in sonar images in the field of detection of underwater structure cracks by using a sonar technology at present is solved, and a basis is provided for subsequent related work of accurate identification of underwater structure cracks through sonar images.

Description

Technical Field

[0001] This invention relates to a method, storage medium, and device for simulating underwater crack sonar images, belonging to the field of sonar image simulation. Background Technology

[0002] Underwater structures (such as dams, sluices, and bridge piers) inevitably develop cracks due to long-term exposure to water and the effects of temperature changes and high water pressure. These cracks not only exist on the concrete surface but also extend into the structure, affecting its strength and service life. Currently, crack detection in underwater structures mainly employs manual diving inspection and underwater optical imaging. However, manual diving inspection is costly, inefficient, and poses significant risks to operators. Underwater optical imaging, on the other hand, is susceptible to the influence of underwater environmental factors such as water depth, current velocity, and turbidity, resulting in poor imaging results.

[0003] Sonar technology, based on biomimetic principles, is primarily used in underwater environments. Unlike optical imaging, which is widely used in surface environments, it utilizes the principle of sound waves propagating in water and receiving echoes to detect the position and shape of target objects. After a series of data processing steps, it further generates visualized sonar images. In the field of underwater structure inspection, compared to artificial diving and underwater optical imaging methods, sonar technology has advantages such as low cost, high efficiency, and less susceptibility to the underwater environment. However, its current applications are mainly focused on large-scale scenarios such as underwater topographic surveying and overall structural deformation detection. The detection and assessment of detailed structural defects (such as concrete cracks) are rarely conducted. The main reason for this is the extremely limited amount of existing sonar data available for crack research, while the morphology of concrete cracks is random, lacking typical representations of various underwater crack morphologies in sonar systems. Summary of the Invention

[0004] This invention provides a method, storage medium, and device for simulating underwater crack sonar images, which solves the problems disclosed in the background art.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A method for simulating underwater crack sonar images includes:

[0007] Based on the optical crack dataset, crack sonar images under different simulation parameters were simulated.

[0008] The process of simulating crack sonar images each time is as follows:

[0009] The crack region in the binary image is migrated to the meshed migration plane in M; where the binary image is the binary image in the optical crack dataset; M is the target model observed in the sonar system in the global coordinate system, and the migration plane is the top surface of M;

[0010] The vertex coordinates of the non-crack mesh in the migration plane, the vertex coordinates of the background plane, and the vertex coordinates of all other planes in M ​​except the migration plane in the global coordinate system are converted to vertex coordinates in the sonar coordinate system; where the background plane is a plane representing the river / seabed.

[0011] Based on the sonar system parameters in the simulation parameters, a spherical coordinate system is established with the origin of the sonar coordinate system, and the sonar rays in the spherical coordinate system are transformed into sonar rays in the sonar coordinate system.

[0012] Based on the sonar ray and vertex coordinates in the sonar coordinate system, calculate the intersection points of the sonar ray with the non-cracked mesh of the migration plane, the other planes in M ​​except the migration plane, and the background plane, and remove the intersection points that are not located inside the corresponding mesh / plane.

[0013] Calculate the distance from the origin of the sonar ray to the internal intersection point. Based on the distance, the intensity coefficient corresponding to the location of the internal intersection point, and the position parameters of the sonar ray, obtain the crack sonar image. The internal intersection point is the intersection point located inside the corresponding grid / plane.

[0014] The simulation parameters also include scaling factors;

[0015] Migrating the crack region in the binary image to the meshed migration plane in M ​​includes:

[0016] The crack region in the binary image is scaled by a scaling factor, and the pixel value of each pixel in the crack region is calculated after scaling.

[0017] Based on the pixel values ​​of each pixel in the scaled crack region, the scaled crack region is migrated to the meshed migration plane in M.

[0018] The formula for calculating the pixel value of each pixel in the scaled crack region is:

[0019] p (u,v) =w 11 ×f(u o1 ,v o1 )+w 12 ×f(u o1 ,v o2 )+w 21 ×f(u o2 ,v o1 )+w 22 ×f(u o2 ,v o2 )

[0020] In the formula, p (u,v) This represents the pixel value of pixel (u,v) in the scaled crack region. Pixel (u,v) represents the pixel with coordinates (u,v). o ,v o ) = (u / s, v / s), pixel (u o ,v o ) represents the pixel corresponding to pixel (u,v) in the original crack region, where pixel (u) o ,v o ) indicates that the coordinates are (u o ,v o (u) pixels, (u) o ,v o () represents floating-point coordinates. L is the scaling factor, and L is the length of the longer side of the scaled crack region in M. c w c Δx represents the number of pixels in the horizontal and vertical directions of the original crack region, respectively, and Δx is the horizontal length of a single mesh after the migration plane meshing. o1 ,v o1 ), f(u) o1 ,v o2 ), f(u) o2 ,v o1 ), f(u) o2 ,v o2 ) represent the pixels in the original crack region (u o1 ,v o1 ), (u o1 ,v o2 ), (u o2 ,v o1 ), (u o2 ,v o2 The pixel value of a pixel (u) o1 ,v o1 ), (u o1 ,v o2 ), (u o2 ,v o1 ), (u o2 ,v o2 ) respectively represent coordinates (u o1 ,v o1 ), (u o1 ,v o2 ), (u o2 ,v o1 ), (u o2 ,v o2 ) pixels, pixels (u o1 ,v o1 ), (u o1 ,vo2 ), (u o2 ,v o1 ), (u o2 ,v o2 ) is a pixel (u o ,v o Four adjacent pixels, w 11 w 12 w 21 w 22 f(u) o1 ,v o1 ), f(u) o1 ,v o2 ), f(u) o2 ,v o1 ), f(u) o2 ,v o2 The weight of w 11 =[1-(u0-u 01 )]·[1-(v0-v 01 )],w 12 =[1-(u0-u 01 )]·(v0-v 01 ), w 21 =(u0-u 01 )·[1-(v0-v 01 )],w 22 =(u0-u 01 )·(v0-v 01 ).

[0021] During migration, each pixel corresponds to a grid. If the pixel value of a pixel in the crack area is not 0 after scaling, it indicates that the pixel is a crack; otherwise, it indicates that the pixel is not a crack.

[0022] The formula for calculating the distance from the origin of the sonar ray to the internal intersection point is:

[0023]

[0024] In the formula, d represents the distance from the origin of the sonar ray to the internal intersection point p. ci distance, Vector in sonar coordinate system directional vector, is the normal vector of the grid / plane in the sonar coordinate system, and o is the origin of the sonar ray. These represent the points from the sonar origin to the internal intersection point p in the sonar coordinate system. ci The vector formed by a vertex p1 of a grid / plane.

[0025] If there are multiple internal intersection points of the sonar rays, select the minimum distance to obtain the crack sonar image.

[0026] Based on the distance, the intensity coefficient corresponding to the location of the internal intersection point, and the position parameters of the sonar rays, obtain the crack sonar image, including:

[0027] Based on the distance, the intensity coefficient corresponding to the location of the internal intersection point, and the position parameters of the sonar ray, plotting data (i,j,d,I) is generated; where i represents the position index of the sonar ray in the θ angle direction, j represents the position index of the sonar ray in the φ angle direction, θ represents the azimuth angle of the sonar device, φ represents the elevation angle of the sonar device, d is the distance from the origin of the sonar ray to the internal intersection point, and I is the intensity coefficient corresponding to the location of the internal intersection point.

[0028] Map the plotting data (i,j,d,I) to the plotting coordinate system. The grid at the location is used, and the grid is filled with color according to I to obtain the crack sonar image; where the drawing coordinate system is represented by polar coordinates, D min and D max N represents the minimum and maximum imaging distances of the sonar device, respectively. d The number of grids is the number of grids in the plotting coordinate system along the polar radius direction, and floor is the floor function.

[0029] A computer-readable storage medium storing one or more programs, the one or more programs including instructions that, when executed by a computing device, cause the computing device to perform an underwater crack sonar image simulation method.

[0030] A computer device includes one or more processors and one or more memories, wherein one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, the one or more programs including instructions for performing an underwater crack sonar image simulation method.

[0031] The beneficial effects achieved by this invention are as follows: This invention transfers the crack region from the centralized binary map of the optical crack dataset to the observation target model of the sonar system, and obtains crack sonar images under different simulation parameters based on the principle of sonar ray tracing. This provides typical acoustic spectra for using sonar equipment to detect underwater cracks, and solves the problem that there is a lack of typical representations of various underwater crack morphologies in sonar images in the current field of applying sonar technology to detect underwater structural cracks. This provides a foundation for subsequent related work on accurately identifying underwater structural cracks through sonar images. Attached Figure Description

[0032] Figure 1 A flowchart simulating a crack sonar image;

[0033] Figure 2 A schematic diagram of the Cartesian coordinate system;

[0034] Figure 3 A flowchart illustrating the migration of the crack region;

[0035] Figure 4 This is a schematic diagram of coordinate transformation between spherical coordinates and sonar coordinates.

[0036] Figure 5 A schematic diagram for determining whether the intersection of a sonar ray and the corresponding grid / plane is located inside the corresponding grid / plane;

[0037] Figure 6 This is a schematic diagram illustrating the calculation of the distance from the origin of the sonar ray to the intersection point of the ray and the interior.

[0038] Figure 7 This is a schematic diagram of the coordinate system for drawing;

[0039] Figure 8 To simulate sonar images of cracks. Detailed Implementation

[0040] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0041] A method for simulating underwater crack sonar images includes simulating crack sonar images under different simulation parameters based on an optical crack dataset; wherein the process of simulating crack sonar images each time is described below. Figure 1 :

[0042] 1) Migrate the crack region in the binary image to the meshed migration plane in M; where the binary image is the binary image in the optical crack dataset; M is the target model observed in the sonar system in the global coordinate system, and the migration plane is the top surface of M.

[0043] 2) Convert the vertex coordinates of the non-crack mesh in the migration plane, the vertex coordinates of the background plane, and the vertex coordinates of all other planes in M ​​except the migration plane in the global coordinate system to vertex coordinates in the sonar coordinate system; where the background plane is the plane representing the river / seabed.

[0044] 3) Based on the sonar system parameters in the simulation parameters, establish a spherical coordinate system with the origin of the sonar coordinate system, and convert the sonar rays in the spherical coordinate system into sonar rays in the sonar coordinate system.

[0045] 4) Based on the sonar ray and vertex coordinates in the sonar coordinate system, calculate the intersection points of the sonar ray with the non-cracked mesh of the migration plane, the other planes in M ​​except the migration plane, and the background plane, and remove the intersection points that are not located inside the corresponding mesh / plane.

[0046] 5) Calculate the distance from the origin of the sonar ray to the internal intersection point. Based on the distance, the intensity coefficient corresponding to the location of the internal intersection point, and the position parameters of the sonar ray, obtain the crack sonar image. The internal intersection point is the intersection point located inside the corresponding grid / plane.

[0047] The above method transfers the crack region from the centralized binary map of the optical crack dataset to the observation target model of the sonar system. Based on the principle of sonar ray tracing, it obtains crack sonar images under different simulation parameters, providing typical acoustic maps for using sonar equipment to detect underwater cracks. This solves the problem that there is a lack of typical representations of various underwater crack morphologies in sonar images in the current field of applying sonar technology to detect underwater structural cracks, and provides a foundation for subsequent related work on accurately identifying underwater structural cracks through sonar images.

[0048] To better simulate sonar images, see Figure 2 Two Cartesian coordinate systems are established in three-dimensional space, named the global coordinate system (O-XYZ) and the sonar coordinate system (O-XYZ). In the global coordinate system, the target model M (a three-dimensional geometric model of the target structure) to be observed in the sonar system and the migration plane P to be used for crack migration are defined. t And the background plane P representing the river / seabed b Among them, the migration plane P t Let M be the top surface. If M is placed directly on the river / seabed, then the background plane P... b If the plane containing the base of M is not the background plane, then the background plane P is the background plane. b The plane containing the bottom surface M is a different plane from the background plane P. b It is usually located below the bottom surface of M.

[0049] The global coordinate system and sonar coordinate system described above are constructed based on actual conditions, and the coordinates between the two coordinate systems have the following transformation relationship:

[0050]

[0051] In the formula, (x,y,z) represents M or P in the global coordinate system. b The coordinates of a point in the coordinate system are (x′, y′, z′), which are the coordinates in the sonar coordinate system after the transformation from (x, y, z). α, β, and γ represent the yaw, pitch, and roll angles that control the attitude of the sonar equipment, respectively, i.e., the angles by which the sonar coordinate system rotates sequentially around the z-axis, y-axis, and x-axis of the global coordinate system. s ,y s ,z s ) represents the coordinates of the sonar ray origin in the global coordinate system.

[0052] The optical crack dataset used for simulation is an optical crack dataset with labeled data (label data is used to identify cracks). Based on the pixel values ​​of each pixel in the binary image of the optical crack dataset, the crack region in the binary image is determined. The crack region in the binary image is scaled according to the scaling factor, and the pixel values ​​of each pixel in the scaled crack region are calculated. Based on the pixel values ​​of each pixel in the scaled crack region, the scaled crack region is migrated to the meshed migration plane in M.

[0053] like Figure 3 As shown, assume P t Divide the grid into m×n grids, where the horizontal and vertical lengths of a single grid cell can be expressed as:

[0054] Δx=l / m

[0055] Δy=w / n

[0056] In the formula, Δx and Δy are the horizontal and vertical lengths of a single grid after the migration plane is meshed, respectively; l and w represent the horizontal and vertical lengths of the migration plane, respectively; and m and n represent the number of grids divided horizontally and vertically, respectively.

[0057] Define the size of the crack region in the binary image as l. c ×w c , where l c w c Let be the number of pixels in the horizontal and vertical directions of the original crack region, respectively. Then the scaling factor can be expressed as:

[0058]

[0059] In the formula, s is the scaling factor, L is the length of the longer side of the scaled crack region in M, and the original crack region becomes l after scaling. c ′×w c ′, where l c ′=floor(s×l c ), w c ′=floor(s×w c ), where floor is the floor function.

[0060] The floating-point coordinates of any pixel in the scaled crack region can be represented as:

[0061] (u o ,v o )=(u / s,v / s)

[0062] In the formula, (u,v) are the coordinates of the pixels in the scaled crack region, (u o ,v o ) represents the coordinates of the original crack region's pixels, i.e., the pixel (u) o ,vo ) represents the pixel point (u,v) in the original crack region, where pixel point (u,v) represents the pixel point with coordinates (u,v). o ,v o ) indicates that the coordinates are (u o ,v o (u) pixels, (u) o ,v o () represents floating-point coordinates;

[0063] Then (u) o ,v o The coordinates of four adjacent pixels can be represented as (u o1 ,v o1 ), (u o1 ,v o2 ), (u o2 ,v o1 ), (u o2 ,v o2 ); where u o1 =floor(u o ), u o2 =floor(u o )+1, v o1 =floor(v o ), v o2 =floor(v o )+1;

[0064] Furthermore, the pixel value at (u,v) can be calculated using a bilinear interpolation algorithm, which can be expressed by the formula:

[0065] p (u,v) =w 11 ×f(u o1 ,v o1 )+w 12 ×f(u o1 ,v o2 )+w 21 ×f(u o2 ,v o1 )+w 22 ×f(u o2 ,v o2 )

[0066] w 11 =[1-(u0-u 01 )]·[1-(v0-v 01 )]

[0067] w 12 =[1-(u0-u 01 )]·(v0-v 01 )

[0068] w 21 =(u0-u 01 )·[1-(v0-v 01 )]

[0069] w 22 =(u0-u 01 )·(v0-v 01 )

[0070] In the formula, p (u,v) Let f(u,v) be the pixel value of pixel (u,v) in the scaled crack region. o1 ,v o1 ), f(u) o1 ,v o2 ), f(u) o2 ,v o1 ), f(u) o2 ,v o2 ) represent the pixels in the original crack region (u o1 ,v o1 ), (u o1 ,v o2 ), (u o2 ,v o1 ), (u o2 ,v o2 The pixel value of w 11 w 12 w 21 w 22 f(u) o1 ,v o1 ), f(u) o1 ,v o2 ), f(u) o2 ,v o1 ), f(u) o2 ,v o2 The weight of ).

[0071] During migration, such as Figure 3 The scaled crack region can be migrated to P t In the lower left corner, each pixel corresponds to a grid. If the pixel value of a pixel in the crack area is not 0 after scaling, it indicates that the pixel is a crack, and the corresponding grid is a crack grid; otherwise, it indicates that the pixel is not a crack, and the corresponding grid is a non-crack grid. This can be represented by a crack discrimination function:

[0072]

[0073] For P t The grid at position (u,v) in the plane, when p (u,v)If the value is not equal to 0 and the crack discrimination function F(u,y) is 1, then the mesh is a cracked mesh. (u,v) If the value is 0, the crack discrimination function F(u,y) is 0, then the mesh is a non-cracked mesh.

[0074] Since the crack region is located at P after the initial migration t To facilitate observation, the area in the lower left corner can be moved; generally, the crack area is moved to P. t Therefore, the crack discrimination function described above can be transformed into:

[0075]

[0076] In the formula, A and B represent the crack region at point P, respectively. t The distance the component is translated along the positive horizontal and vertical axes; the final structural component after translation. Figure 3 Figure e in the diagram.

[0077] For P t traverse P t In the mesh, if the crack discrimination function is 0, meaning the mesh is a non-cracked mesh, then the coordinates of the four vertices of the mesh are taken; for P b The P taken b The four vertices of P b The area enclosed by the four vertices should cover the sonar rays at P b The projection range in the image is such that the coordinates of these four vertices should be large enough. Here, we take (-100, 100, 0), (100, 100, 0), (100, -100, 0), and (-100, -100, 0) as P. b The coordinates of the four vertices are taken; for the other planes of M, the coordinates of the four vertices are taken; further, according to the above formula, the vertex coordinates in the global coordinate system are converted to the vertex coordinates in the sonar coordinate system.

[0078] Based on the sonar system parameters in the simulation parameters, namely the sonar position and rotation angle, a spherical coordinate system is established with the origin of the sonar coordinate system. The sonar ray emission range [θ] is determined according to the azimuth and elevation angle ranges of the simulated sonar equipment. min ,θ max ]、[φ min ,φ max ]; where, [θ min ,θ max [θ] represents the range of θ, where θ is the azimuth angle of the simulated sonar device, i.e., the angle between the projection of the sonar ray onto the horizontal plane and the positive x-axis of the spherical coordinate system. min ,θ max ] represents the range of φ, where φ is the pitch angle of the simulated sonar device, i.e., the angle between the sonar ray and the positive direction of the z-axis of the spherical coordinate system.

[0079] N is uniformly distributed in the θ and φ directions respectively. θ and N φ A sonar beam is used for simulated imaging; therefore, this sonar system has a total of N beams. θ ×N φ A sonar ray, for any position (i,j) within the sonar system, is a sonar ray. It can be represented as:

[0080]

[0081] In the formula, t represents any non-negative real number. Let i represent the direction vector of the sonar ray, where i represents the position index of the sonar ray in the direction of angle θ, and j represents the position index of the sonar ray in the direction of angle φ.

[0082] Any point p on the sonar ray s The coordinates in the sonar coordinate system can be represented as:

[0083]

[0084]

[0085]

[0086] In the formula, (p y ′,p y ′,p z ′) is p s The coordinates in the sonar coordinate system; based on this formula, the sonar ray in the spherical coordinate system can be converted into the sonar ray in the sonar coordinate system.

[0087] In the global coordinate system, the four vertices of the other planes in the mesh / background plane / M, excluding the migration plane, are denoted as p1(x). p1 ,y p1 ,z p1 p2(x) p2 ,y p2 ,z p2 p3(x) p3 ,y p3 ,z p3 p4(x) p4 ,y p4 ,z p4 Therefore, the coordinates in the sonar coordinate system can be expressed as:

[0088]

[0089] The normal vector of the corresponding mesh / plane in the sonar coordinate system It can be represented as:

[0090]

[0091] In the sonar coordinate system, the sonar ray intersects the grid / plane at point p. c That is, the intersection point, the vector The following relationship must be satisfied:

[0092]

[0093] In the formula, o is the origin of the sonar ray in the sonar coordinate system. These represent the distances from the sonar origin to the intersection point p in the sonar coordinate system. c The vector formed by a vertex p1 of the corresponding grid / plane.

[0094] Furthermore, vectors It can be represented as:

[0095]

[0096] In the formula, For vectors The direction vector.

[0097] Furthermore, there are:

[0098]

[0099] Furthermore, vectors That is, point p c The coordinates can be represented as:

[0100]

[0101] In the formula, Used to ensure that sonar rays intersect with the outer surface of the target structure.

[0102] Further determine p using the following formula c Whether it is located inside the corresponding grid / plane, see details. Figure 5 :

[0103]

[0104]

[0105]

[0106]

[0107] If the above formula holds true, it indicates that the intersection point p cLocated inside the corresponding grid / plane, denoted as p ci Conversely, the surface intersection point p c If the location is outside the corresponding grid / plane, remove it. Calculate the distance between the origin of the sonar ray and the internal intersection point, where the internal intersection point is the intersection point located inside the corresponding grid / plane. See [link / reference]. Figure 6 :

[0108]

[0109] In the formula, d represents the distance from the origin of the sonar ray to the internal intersection point p. ci distance, Vector in sonar coordinate system directional vector, is the normal vector of the grid / plane in the sonar coordinate system, and o is the origin of the sonar ray. These represent the points from the sonar origin to the internal intersection point p in the sonar coordinate system. ci The vector formed by a vertex p1 of a grid / plane.

[0110] Traverse each sonar ray in the sonar system and calculate the distance between the sonar ray and its intersection point. If there are one or more grids / planes such that the intersection point of the sonar ray and the sonar ray is located inside the grid / plane, take the minimum distance. That is, if there are multiple internal intersection points of the sonar ray, select the minimum distance to obtain the crack sonar image.

[0111] Based on the distance, the intensity coefficient corresponding to the location of the internal intersection point, and the position parameters of the sonar ray, plotting data (i,j,d,I) is generated; where I is the intensity coefficient corresponding to the location of the internal intersection point, which is 1 when the internal intersection point is located at M, and 1 when the intersection point is located at P. b When the value is 0.5, take 0.5.

[0112] Establish a plotting coordinate system and mesh it. The plotting coordinate system is represented by polar coordinates (ρ, θ′), where ρ represents the polar radius and D... min ≤ρ≤D max θ′ represents the polar angle, θ min ≤θ′≤θ max D min D max θ min θ max Based on the parameter values ​​of the simulated sonar device, D min and D max θ represents the minimum and maximum distances at which the sonar device can image data. min and θ max These represent the minimum and maximum azimuth angles, respectively. N is divided along the polar radius and polar angle directions, respectively. d and N θThere are N grids, therefore the drawing coordinate system has a total of N. d ×N θ See grid. Figure 7 .

[0113] Map the plotting data (i,j,d,I) to the plotting coordinate system. The grid at the location is used, and the grid is filled with color according to I to obtain the crack sonar image, see... Figure 8 Where I=1 fills white, I=0.5 fills gray, and for grids not mapped in the drawing coordinate system, black is filled; if there are two or more sets of drawing data, with the same parameters i and d, but different parameters j, the maximum value of I is taken as the final drawing data.

[0114] The above method solves the problem that there is a lack of typical representations of various underwater crack morphologies in sonar images in the current field of sonar technology for detecting underwater structural cracks, and provides a foundation for subsequent related work on accurately identifying underwater structural cracks through sonar images.

[0115] Based on the same technical solution, the present invention also discloses a computer-readable storage medium that stores one or more programs, the one or more programs including instructions that, when executed by a computing device, cause the computing device to perform an underwater crack sonar image simulation method.

[0116] Based on the same technical solution, the present invention also discloses a computer device, including one or more processors and one or more memories, wherein one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, and the one or more programs include instructions for performing an underwater crack sonar image simulation method.

[0117] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0118] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0119] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0120] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0121] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of the claims of the present invention pending approval.

Claims

1. A method for simulating underwater crack sonar images, characterized in that, include: Based on the optical crack dataset, crack sonar images under different simulation parameters were simulated. The process of simulating crack sonar images each time is as follows: The crack region in the binary image is migrated to the meshed migration plane in M; where the binary image is the binary image in the optical crack dataset; M is the target model observed in the sonar system in the global coordinate system, and the migration plane is the top surface of M; The vertex coordinates of the non-crack mesh in the migration plane, the vertex coordinates of the background plane, and the vertex coordinates of all other planes in M ​​except the migration plane in the global coordinate system are converted to vertex coordinates in the sonar coordinate system; where the background plane is a plane representing the river / seabed. Based on the sonar system parameters in the simulation parameters, a spherical coordinate system is established with the origin of the sonar coordinate system, and the sonar rays in the spherical coordinate system are transformed into sonar rays in the sonar coordinate system. Based on the sonar ray and vertex coordinates in the sonar coordinate system, calculate the intersection points of the sonar ray with the non-cracked mesh of the migration plane, the other planes in M ​​except the migration plane, and the background plane, and remove the intersection points that are not located inside the corresponding mesh / plane. Calculate the distance from the origin of the sonar ray to the internal intersection point. Based on the distance, the intensity coefficient corresponding to the location of the internal intersection point, and the position parameters of the sonar ray, obtain the crack sonar image. The internal intersection point is the intersection point located inside the corresponding grid / plane.

2. The underwater crack sonar image simulation method according to claim 1, characterized in that, The simulation parameters also include scaling factors; Migrating the crack region in the binary image to the meshed migration plane in M ​​includes: The crack region in the binary image is scaled by a scaling factor, and the pixel value of each pixel in the crack region is calculated after scaling. Based on the pixel values ​​of each pixel in the scaled crack region, the scaled crack region is migrated to the meshed migration plane in M.

3. The underwater crack sonar image simulation method according to claim 2, characterized in that, The formula for calculating the pixel value of each pixel in the scaled crack region is: p (u,v) =w 11 ×f(u o1 ,v o1 )+w 12 ×f(u o1 ,v o2 )+w 21 ×f(u o2 ,v o1 )+w 22 ×f(u o2 ,v o2 ) In the formula, p (u,v) This represents the pixel value of pixel (u,v) in the scaled crack region. Pixel (u,v) represents the pixel with coordinates (u,v). o ,v o ) = (u / s, v / s), pixel (u o ,v o ) represents the pixel corresponding to pixel (u,v) in the original crack region, where pixel (u) o ,v o ) indicates that the coordinates are (u o ,v o (u) pixels, (u) o ,v o () represents floating-point coordinates. L is the scaling factor, and L is the length of the longer side of the scaled crack region in M. c w c Δx represents the number of pixels in the horizontal and vertical directions of the original crack region, respectively, and Δx is the horizontal length of a single mesh after the migration plane meshing. o1 ,v o1 ), f(u) o1 ,v o2 ), f(u) o2 ,v o1 ), f(u) o2 ,v o2 ) represent the pixels in the original crack region (u o1 ,v o1 ), (u o1 ,v o2 ), (u o2 ,v o1 ), (u o2 ,v o2 The pixel value of a pixel (u) o1 ,v o1 ), (u o1 ,v o2 ), (u o2 ,v o1 ), (u o2 ,v o2 ) respectively represent coordinates (u o1 ,v o1 ), (u o1 ,v o2 ), (u o2 ,v o1 ), (u o2 ,v o2 ) pixels, pixels (u o1 ,v o1 ), (u o1 ,v o2 ), (u o2 ,v o1 ), (u o2 ,v o2 ) is related to pixel (u o ,v o Four adjacent pixels, w 11 w 12 w 21 w 22 f(u) o1 ,v o1 ), f(u) o1 ,v o2 ), f(u) o2 ,v o1 ), f(u) o2 ,v o2 The weight of w 11 =[1-(u0-u 01 )]·[1-(v0-v 01 )],w 12 =[1-(u0-u 01 )]·(v0-v 01 ), w 21 =(u0-u 01 )·[1-(v0-v 01 )],w 22 =(u0-u 01 )·(v0-v 01 ).

4. The underwater crack sonar image simulation method according to claim 2, characterized in that, During migration, each pixel corresponds to a grid. If the pixel value of a pixel in the crack area is not 0 after scaling, it indicates that the pixel is a crack; otherwise, it indicates that the pixel is not a crack.

5. The underwater crack sonar image simulation method according to claim 1, characterized in that, The formula for calculating the distance from the origin of the sonar ray to the internal intersection point is: In the formula, d represents the distance from the origin of the sonar ray to the internal intersection point p. ci distance, Vector in sonar coordinate system directional vector, is the normal vector of the grid / plane in the sonar coordinate system, and o is the origin of the sonar ray. These represent the points from the sonar origin to the internal intersection point p in the sonar coordinate system. ci The vector formed by a vertex p1 of a grid / plane.

6. The underwater crack sonar image simulation method according to claim 1, characterized in that, If there are multiple internal intersection points of the sonar rays, select the minimum distance to obtain the crack sonar image.

7. The underwater crack sonar image simulation method according to claim 1 or 6, characterized in that, Based on the distance, the intensity coefficient corresponding to the location of the internal intersection point, and the position parameters of the sonar rays, obtain the crack sonar image, including: Based on the distance, the intensity coefficient corresponding to the location of the internal intersection point, and the position parameters of the sonar ray, plotting data (i,j,d,I) is generated; where i represents the position index of the sonar ray in the θ angle direction, j represents the position index of the sonar ray in the φ angle direction, θ represents the azimuth angle of the sonar device, φ represents the elevation angle of the sonar device, d is the distance from the origin of the sonar ray to the internal intersection point, and I is the intensity coefficient corresponding to the location of the internal intersection point. Map the plotting data (i,j,d,I) to the plotting coordinate system. The grid at the location is used, and the grid is filled with color according to I to obtain the crack sonar image; where the drawing coordinate system is represented by polar coordinates, D min and D max N represents the minimum and maximum imaging distances of the sonar device, respectively. d The number of grids is the number of grids in the plotting coordinate system along the polar radius direction, and floor is the floor function.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores one or more programs, the one or more programs including instructions that, when executed by a computing device, cause the computing device to perform any of the methods described in claims 1 to 7.

9. A computer device, characterized in that, include: One or more processors and one or more memories, one or more programs stored in the one or more memories and configured to be executed by the one or more processors, the one or more programs including instructions for performing any of the methods of claims 1 to 7.

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