Fishery resource quantity evaluation method based on fishery horizontal scanning sonar

Abstract

The invention provides a fish school resource quantity evaluation method based on fishery horizontal scanning sonar, and relates to the technical field of fish school detection. The method comprises the following steps: acquiring echo data sent by shipborne horizontal scanning sonar equipment; performing coordinate transformation on the original echo image according to the polar coordinate data of each pixel point in the original echo image to obtain an original echo image under a vertical coordinate system; performing denoising processing on the original echo image to obtain a denoised echo image; performing edge feature detection on the de-noised echo image to obtain a fish school contour feature map; determining fish school feature parameters according to the fish school contour feature map; and according to the fish school feature parameters and the original echo image, generating and displaying a fish school geographic plotting chart, so that the position information and the feature parameters of fish school resources in a large range can be known more visually, the purpose of evaluating the fish school resource quantity in the whole fishing ground is achieved, and the efficiency of ship fishing operation is effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of fish school detection, and in particular to a method for assessing fish school resources based on fishery horizontal scanning sonar. Background Art

[0002] Fish detection is an important field in fisheries and marine science research. Its main purpose is to determine the location, size and density of fish schools in the water, and then track and target fish schools based on the detected fish school information, thereby improving the efficiency of fish fishing operations. Among them, since most of the operations in the polar oceans are distributed in fishing grounds signed by multiple countries, it is necessary to effectively evaluate the amount of fish resources in the fishing grounds, and on this basis, formulate a selective fishing plan for the fish schools to ensure that the fish schools are fished with the optimal allocation of resources within the fishery agreement quota.

[0003] In the related art, most fishing boats use fish finders to detect fish school information. Specifically, a transmitter in the fish finder emits vertical sound waves into the water, and calculates the position and size information of the fish school based on the sound wave signals reflected by underwater objects.

[0004] However, the detection sound waves emitted by the fish finder are vertical beams, that is, they only detect in the vertical direction of the ship's position, and cannot achieve large-scale fish information detection during the fishery production process. Summary of the invention

[0005] The purpose of the present invention is to provide a method for assessing fish stock abundance based on fishery horizontal scanning sonar in order to solve the technical problems existing in the prior art in view of the above-mentioned deficiencies in the prior art.

[0006] To achieve the above purpose, the technical solution adopted in the embodiment of the present application is as follows:

[0007] In a first aspect, an embodiment of the present application provides a method for assessing fish stock abundance based on fishery horizontal scanning sonar, the method comprising:

[0008] Acquire echo data sent by a ship-borne horizontal scanning sonar device, the echo data including: an original echo image and polar coordinate data of each pixel point in the original echo image, the polar coordinate data including: a relative ship position angle and a relative ship position distance;

[0009] According to the polar coordinate data of each pixel point in the original echo image, coordinate transformation is performed on the original echo image to obtain an original echo image in a vertical coordinate system;

[0010] Performing denoising processing on the original echo image to obtain a denoised echo image; wherein the denoising processing is used to eliminate the sea wave signal and the wake reverberation signal in the original echo image;

[0011] Performing edge feature detection on the denoised echo image to obtain a fish school contour feature map;

[0012] Determine fish school characteristic parameters according to the fish school contour characteristic diagram, wherein the fish school characteristic parameters include: fish school center of gravity coordinates and fish school cross-sectional area;

[0013] A fish school geographic plot is generated and displayed according to the fish school characteristic parameters and the original echo image.

[0014] Optionally, performing coordinate transformation on the original echo image according to the polar coordinate data of each pixel point in the original echo image to obtain an original echo image in a vertical coordinate system includes:

[0015] Performing spatial distance compensation correction on the polar coordinate data of each pixel point to obtain corrected polar coordinate data of each pixel point;

[0016] Taking the position point of the ship as the origin, establishing a vertical coordinate system, and obtaining a first conversion relationship between the vertical coordinate system and the polar coordinate system;

[0017] The corrected polar coordinate data of each pixel point is subjected to coordinate transformation according to the first transformation relationship to generate an original echo image in the vertical coordinate system.

[0018] Optionally, performing spatial distance compensation correction on the polar coordinate data of each pixel point to obtain corrected polar coordinate data of each pixel point includes:

[0019] Obtaining a polar angle correction formula corresponding to the polar angle and a polar diameter correction formula corresponding to the polar diameter in the polar coordinate system;

[0020] Inputting the polar angle in the polar coordinate data of each pixel point into the polar angle correction formula to obtain the corrected polar angle of each pixel point;

[0021] Inputting the polar diameter in the polar coordinate data of each pixel point into the polar diameter correction formula to obtain the corrected polar diameter of each pixel point;

[0022] Based on the corrected polar angle of each pixel point and the corrected polar diameter of each pixel point, the corrected polar coordinate data of each pixel point is obtained.

[0023] Optionally, the performing denoising on the original echo image to obtain a denoised echo image includes:

[0024] Determine the channel color map of the original echo image under each channel;

[0025] Determining a monotone gradient echo intensity feature according to a channel color map under each of the channels;

[0026] According to the monotonically gradient echo intensity feature and the color threshold corresponding to the preset echo intensity, a plurality of echo data satisfying the color threshold are obtained;

[0027] Connected domain detection is performed on the plurality of echo data satisfying the color threshold, and the denoised original echo image is obtained according to the connected domain detection result.

[0028] Optionally, determining the monotonically gradient echo intensity feature according to the channel color map under each of the channels includes:

[0029] Comparing the contrast of the channel color map under each of the channels, and taking the channel color map with the largest contrast as the main reference channel;

[0030] According to the preset echo intensity range corresponding to the shipborne sonar color scale, the main reference channel is mapped and segmented to obtain the monotonically gradient echo intensity feature.

[0031] Optionally, performing edge feature detection on the denoised echo image to obtain a fish school outline feature map includes:

[0032] grayscale the denoised echo image to generate a target grayscale image;

[0033] Perform contour extraction according to the target grayscale image to obtain pixel gradients and pixel gradient directions of each pixel in the target grayscale image;

[0034] According to a preset gradient threshold and the pixel gradient and the pixel gradient direction of each pixel, a plurality of target pixel points that meet the gradient threshold are screened out;

[0035] Performing an opening and closing check on the plurality of target pixel points to determine whether the plurality of target pixel points form a closed pixel area;

[0036] If not, a plurality of coordinate points on the shortest distance between the end pixel points that do not form a closed line are obtained, and interpolation processing is performed on the plurality of coordinate points on the shortest distance to obtain the fish school outline feature map.

[0037] Optionally, determining fish school characteristic parameters according to the fish school profile characteristic graph includes:

[0038] Segmenting the fish school outline feature graph into a plurality of graphs;

[0039] Determine the center of gravity and area of ​​each of the figures, and determine the coordinates of the center of gravity of the school of fish according to the center of gravity and area of ​​each of the figures;

[0040] Obtaining the number of pixels in the dot matrix and the number of pixels at the edge of the outline in the fish school outline feature map;

[0041] The cross-sectional area of ​​the school of fish is obtained according to the number of pixels in the dot matrix and the number of pixels at the edge of the contour.

[0042] Optionally, generating and displaying a geographical map of a school of fish according to the characteristic parameters of the school of fish and the original echo image comprises:

[0043] According to a pre-established second conversion relationship between the earth's longitude and latitude coordinate system and the vertical coordinate system and the coordinates of the center of gravity of the fish school, the longitude and latitude coordinates corresponding to the coordinates of the center of gravity of the fish school are obtained;

[0044] Generate an echo latitude map of the original echo image in the earth's longitude and latitude coordinate system according to the second conversion relationship and the original echo image;

[0045] According to the coordinates of the center of gravity of the fish school and the position point of the ship, the azimuth and distance of the fish school relative to the ship are obtained;

[0046] The coordinates of the fish school's center of gravity, the cross-sectional area of ​​the fish school, the longitude and latitude coordinates corresponding to the coordinates of the fish school's center of gravity, and the azimuth and distance of the fish school relative to the ship are added to the echo latitude map to generate a geographically plotted nautical chart of the fish school.

[0047] In a second aspect, an embodiment of the present application further provides a fish school information detection device, the method comprising:

[0048] An acquisition module is used to acquire echo data sent by a ship-borne horizontal scanning sonar device, wherein the echo data includes: an original echo image and polar coordinate data of each pixel point in the original echo image, wherein the polar coordinate data includes: a relative ship position angle and a relative ship position distance;

[0049] A conversion module, used for performing coordinate conversion on the original echo image according to the polar coordinate data of each pixel point in the original echo image to obtain an original echo image in a vertical coordinate system;

[0050] A denoising module, used for performing denoising processing on the original echo image to obtain a denoised echo image; wherein the denoising processing is used to eliminate the sea wave signal and the wake reverberation signal in the original echo image;

[0051] A detection module is used to perform edge feature detection on the denoised echo image to obtain a fish school outline feature map;

[0052] A determination module, used to determine fish school characteristic parameters according to the fish school outline characteristic map, wherein the fish school characteristic parameters include: fish school center of gravity coordinates and fish school cross-sectional area;

[0053] A generation module is used to generate and display a geographically plotted nautical chart of a school of fish based on the characteristic parameters of the school of fish and the original echo image.

[0054] In a third aspect, an embodiment of the present application further provides an electronic device, comprising: a processor, a storage medium and a bus, wherein the storage medium stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor communicates with the storage medium via the bus, and the processor executes the machine-readable instructions to perform the steps of the method for assessing fish stock quantities based on fishery horizontal scanning sonar as provided in the first aspect.

[0055] In a fourth aspect, an embodiment of the present application further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method for assessing fish stock quantity based on fishery horizontal scanning sonar as provided in the first aspect is executed.

[0056] The beneficial effects of this application are:

[0057] The present application provides a method for assessing the amount of fish resources based on a fishery horizontal scanning sonar, the method comprising: acquiring echo data sent by a ship-borne horizontal scanning sonar device, the echo data comprising: an original echo image and polar coordinate data of each pixel in the original echo image, the polar coordinate data comprising: a relative ship position angle and a relative ship position distance; performing coordinate transformation on the original echo image according to the polar coordinate data of each pixel in the original echo image to obtain an original echo image in a vertical coordinate system; performing denoising processing on the original echo image to obtain a denoised echo image; wherein the denoising processing is used to eliminate sea wave signals and wake reverberation signals in the original echo image; performing edge feature detection on the denoised echo image to obtain a fish school contour feature map; determining fish school feature parameters according to the fish school contour feature map, the fish school feature parameters comprising: fish school center of gravity coordinates and fish school cross-sectional area; generating and displaying a fish school geographic plotted nautical chart according to the fish school feature parameters and the original echo image. In this scheme, in order to realize the detection of fish information over a large range, a horizontal scanning sonar device is used to perform horizontal scanning over a large range, that is, the echo data received by the horizontal scanning sonar device contains the fish information in a large range of waters, which solves the problem that the fish finder used in the related technology cannot realize the detection of fish information over a large range; at the same time, in order to realize the efficient identification and quantitative evaluation of the amount of fish resources, the polar coordinate system data of each pixel point in the original echo image is first converted into the geodetic vertical coordinate system to generate the original echo image under the vertical coordinate system, so as to achieve the purpose of unified calibration processing of the sonar data; then After that, the original echo image is processed by denoising, edge feature detection, etc. to obtain the fish school contour features, and based on the fish school contour features, the fish school characteristic parameters are calculated, such as the fish school center of gravity coordinates, fish school cross-sectional area, etc. Finally, based on the fish school characteristic parameters and the original echo image, a fish school geographic mapping chart is generated and displayed, so that the location information and characteristic parameters of fish resources in a large area of ​​water can be more intuitively understood, so as to achieve the purpose of evaluating the fish resource quantity in the entire fishing ground, so that fishermen can quickly understand the size and distribution range of the detected fish resources, and effectively improve the efficiency of ship fishing operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0059] Figure 1 A schematic diagram of a flow chart of a method for assessing fish stock abundance based on fishery horizontal scanning sonar provided in an embodiment of the present application;

[0060] Figure 2 The original echo image in the polar coordinate system obtained in the embodiment of the present application;

[0061] Figure 3 The original echo image in the vertical coordinate system provided in the embodiment of the present application;

[0062] Figure 4 A flow chart of another method for assessing fish stock based on fishery horizontal scanning sonar provided in an embodiment of the present application;

[0063] Figure 5 A flow chart of another method for assessing fish stock based on fishery horizontal scanning sonar provided in an embodiment of the present application;

[0064] Figure 6 A flow chart of another method for assessing fish stock based on fishery horizontal scanning sonar provided in an embodiment of the present application;

[0065] Figure 7 A channel color image under the red primary color R channel provided in an embodiment of the present application;

[0066] Figure 8 A channel color diagram under the green primary color G channel provided in an embodiment of the present application;

[0067] Fig. 9 A channel color image under the blue primary color B channel provided in an embodiment of the present application;

[0068] Fig.10 The original echo image after denoising provided in the embodiment of the present application;

[0069] Fig.11 A flow chart of another method for assessing fish stock based on fishery horizontal scanning sonar provided in an embodiment of the present application;

[0070] Fig.12 A flow chart of another method for assessing fish stock based on fishery horizontal scanning sonar provided in an embodiment of the present application;

[0071] Fig.13 The extracted fish school contour feature map provided in the embodiment of the present application;

[0072] Fig.14 A flow chart of another method for assessing fish stock based on fishery horizontal scanning sonar provided in an embodiment of the present application;

[0073] Fig.15 A flow chart of another method for assessing fish stock based on fishery horizontal scanning sonar provided in an embodiment of the present application;

[0074] Fig.16 A geographically plotted nautical chart of fish schools provided for an embodiment of the present application;

[0075] Fig.17 The embodiment of the present application provides adding the fish school position and characteristic parameters to the original echo image in the form of a label frame;

[0076] Fig.18 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0077] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the drawings in the present application only serve the purpose of explanation and description and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn in real proportion. The flowchart used in this application shows the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowchart can be implemented out of sequence, and the steps without logical context can be reversed in order or implemented simultaneously. In addition, those skilled in the art can add one or more other operations to the flowchart under the guidance of the content of the present application, or remove one or more operations from the flowchart.

[0078] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0079] It should be noted that the term "comprising" will be used in the embodiments of the present application to indicate the existence of the features declared thereafter, but does not exclude the addition of other features.

[0080] The implementation principles and corresponding beneficial effects of the multi-engine data processing method steps provided in this application will be explained through multiple specific embodiments as follows.

[0081] In one embodiment, reference Figure 1As shown, a flow chart of a method for assessing the amount of fish stocks based on fishery horizontal scanning sonar is provided. Optionally, the method can be performed by a device with data processing function such as a personal computer, a laptop, a smart phone, and a tablet computer. It should be understood that in other embodiments, the order of some steps in the method for assessing the amount of fish stocks based on fishery horizontal scanning sonar can be interchanged according to actual needs, or some steps can be omitted or deleted. Figure 1 As shown, the method includes:

[0082] S101. Acquire echo data sent by a ship-borne horizontal scanning sonar device.

[0083] The echo data includes: the original echo image and the polar coordinate data of each pixel point in the original echo image, and the polar coordinate data (θ, r) includes: the relative ship position angle θ and the relative ship position distance r.

[0084] In this scheme, in order to solve the problem of insufficient information in the related art of using a horizontal umbrella beam to measure the horizontal position of a school of fish, it is proposed to set a horizontal scanning sonar on the fishing boat, take the ship position as the origin, send a sonar signal to the area to be detected by the transmitter on the horizontal scanning sonar, and obtain the echo data received by the receiver on the receiving horizontal scanning sonar. Among them, the echo data includes: the original echo image and the polar coordinate data of each pixel in the original echo image.

[0085] Among them, unlike vertical scanning sonar, horizontal scanning sonar mainly focuses on detection in the horizontal direction, which can realize large-scale fish information detection and can collect high-resolution echo images.

[0086] For example, reference Figure 2 As shown, it is the original echo image acquired at a certain moment, and the original echo image is a three-channel color image.

[0087] Among them, the polar coordinate data (θ, r) of each pixel point in the original echo image is a radar display mode (Plan-Position Indicator, PPI) coordinate system with the ship position as the origin and the bow upward in a circular distribution, and the bow is zero, the clockwise positive ship position angle θ and the distance r from the center of the ship position are the axes.

[0088] S102 . According to the polar coordinate data of each pixel point in the original echo image, coordinate transformation is performed on the original echo image to obtain an original echo image in a vertical coordinate system.

[0089] Among them, horizontal scanning sonar can have higher resolution and signal analysis technology. Specifically, in the production process, the ship-borne horizontal scanning sonar can achieve more accurate detection of fish targets. Scanning sonar data is often stored in the form of a matrix, but the actual detection range is collected in the form of fan-shaped divergence, and the obtained sonar data has large deviations at different distance scales. In this study, by analyzing the coordinate point positions of sonar data in different coordinate systems, it is converted from the polar coordinate system based on the ship position to the vertical geographic coordinate system of the earth, and the spatial correction of the relevant echo coordinates is achieved.

[0090] Optionally, in order to facilitate processing of the original echo image, the original echo image is converted, that is, the original echo image in the polar coordinate system is converted into the original echo image in the vertical coordinate system. Figure 3 As shown, it is the original echo image in the vertical coordinate system obtained after conversion.

[0091] S103, performing denoising processing on the original echo image to obtain a denoised echo image.

[0092] Among them, denoising processing is used to eliminate the wave signal and wake reverberation signal in the original echo image.

[0093] Optionally, in order to improve the processing quality of the original echo image, the original echo image also needs to be denoised, such as using commonly used spatial domain filtering, frequency domain filtering, time domain filtering and other filtering methods to denoise the original echo image to filter out background noise in the original echo image, such as wave signals and wake reverberation signals, to obtain a denoised echo image.

[0094] S104, performing edge feature detection on the denoised echo image to obtain a fish school outline feature map.

[0095] Optionally, it is also necessary to use edge detection operators, such as Canny edge detection, Sobel operator, Laplacian operator, etc., to perform edge feature detection on the denoised echo image, so as to extract the contour feature information of the fish school from the denoised echo image, so as to better analyze and identify the fish school's characteristic parameters such as the position, shape and density of the fish school.

[0096] S105, determining fish school characteristic parameters according to the fish school outline characteristic map.

[0097] Among them, the fish school characteristic parameters include: fish school center of gravity coordinates, fish school cross-sectional area, fish school species, etc.

[0098] Optionally, the coordinates of the center of gravity of the fish school can be calculated based on the position of the center of gravity of the fish school contour feature map; and the cross-sectional area of ​​the fish school can be calculated based on the area of ​​the fish school contour feature map; secondly, the circumference of the fish school can also be calculated based on the edge length of the fish school contour feature map.

[0099] S106, generating and displaying a geographically plotted nautical chart of the fish school based on the fish school characteristic parameters and the original echo image.

[0100] Optionally, in order to more intuitively understand the location information and characteristic parameters of fish resources, for example, the fish characteristic parameters can be directly added to the original echo image to generate a fish geographical plotting chart; or, the original echo image in the vertical coordinate system is converted into a longitude and latitude map in the earth's longitude and latitude coordinate system, and the fish characteristic parameters are added to the longitude and latitude map to generate a fish geographical plotting chart. In this way, the evaluation results can be directly presented on the original echo image through information tags, so that the operator can quickly understand the resource size and distribution range of the detection target, and realize fast and accurate fish resource evaluation, providing fishery production practitioners with an intuitive and concise fishing navigation solution, which has application and promotion value for offshore fishery production.

[0101] In summary, an embodiment of the present application provides a method for assessing fish resource quantity based on fishery horizontal scanning sonar, the method comprising: acquiring echo data sent by a ship-borne horizontal scanning sonar device, the echo data comprising: an original echo image and polar coordinate data of each pixel in the original echo image, the polar coordinate data comprising: a relative ship position angle and a relative ship position distance; performing coordinate transformation on the original echo image according to the polar coordinate data of each pixel in the original echo image to obtain an original echo image in a vertical coordinate system; performing denoising processing on the original echo image to obtain a denoised echo image; wherein the denoising processing is used to eliminate the wave signal and the wake reverberation signal in the original echo image; performing edge feature detection on the denoised echo image to obtain a fish school contour feature map; determining fish school characteristic parameters according to the fish school contour feature map, the fish school characteristic parameters comprising: the coordinates of the fish school center of gravity and the fish school cross-sectional area; generating and displaying a fish school geographic plotted nautical chart according to the fish school characteristic parameters and the original echo image. In this scheme, in order to realize the detection of fish information over a large range, a horizontal scanning sonar device is used to perform horizontal scanning over a large range, that is, the echo data received by the horizontal scanning sonar device contains the fish information in a large range of waters, which solves the problem that the fish finder used in the related technology cannot realize the detection of fish information over a large range; at the same time, in order to realize the efficient identification and quantitative evaluation of the amount of fish resources, the polar coordinate system data of each pixel point in the original echo image is first converted into the geodetic vertical coordinate system to generate the original echo image under the vertical coordinate system, so as to achieve the purpose of unified calibration processing of the sonar data; then After that, the original echo image is processed by denoising, edge feature detection, etc. to obtain the fish school contour features, and based on the fish school contour features, the fish school characteristic parameters are calculated, such as the fish school center of gravity coordinates, fish school cross-sectional area, etc. Finally, based on the fish school characteristic parameters and the original echo image, a fish school geographic mapping chart is generated and displayed, so that the location information and characteristic parameters of fish resources in a large area of ​​water can be more intuitively understood, so as to achieve the purpose of evaluating the fish resource quantity in the entire fishing ground, so that fishermen can quickly understand the size and distribution range of the detected fish resources, and effectively improve the efficiency of ship fishing operations.

[0102] Optionally, refer to Figure 4 As shown, the above step S102 includes:

[0103] S401 , performing spatial distance compensation correction on the polar coordinate data of each pixel point to obtain corrected polar coordinate data of each pixel point.

[0104] Optionally, considering that the polar coordinate data of each pixel in the original echo image sent by the horizontal scanning sonar device has a certain error, before the coordinate conversion of the original echo image, it is also necessary to perform spatial distance compensation correction on the polar coordinate data of each pixel in the original echo image to obtain the corrected polar coordinate data of each pixel (θcorr , r corr ), thereby ensuring the accuracy and reliability of subsequent processing results.

[0105] S402: Establish a vertical coordinate system with the location of the ship as the origin, and obtain a first conversion relationship between the vertical coordinate system and the polar coordinate system.

[0106] Among them, the vertical coordinate system takes the center of the ship as the origin, the right side of the ship as the positive direction of the X-axis, and the bow as the positive direction of the Y-axis. The vertical coordinate system of the center of the ship is established according to the image pixel point, and the first conversion relationship between the vertical coordinate system and the polar coordinate system is determined, that is, the first conversion relationship is used to characterize the corresponding calculation formula between each coordinate point in the vertical coordinate system and each coordinate point in the polar coordinate system.

[0107] Exemplarily, the first conversion relationship is x=r corr ·cos(θ corr ), y=r corr ·sin(θ corr ).

[0108] S403, performing coordinate transformation on the corrected polar coordinate data of each pixel point according to the first transformation relationship to generate an original echo image in a vertical coordinate system.

[0109] Optionally, after determining the first conversion relationship, the corrected polar coordinate data (θ corr , r corr ) is input into the first conversion relation to obtain the converted vertical coordinate data of each pixel point, and based on the converted vertical coordinate data of each pixel point, the original echo image in the vertical coordinate system is generated (i.e. Figure 2 That is, the original echo image is an image in the vertical coordinate system of the center of the ship with the right side of the ship as the positive direction of the X axis and the bow of the ship as the positive direction of the Y axis, and with the image pixel points as the unit.

[0110] Optionally, in this solution, the polar coordinate system data of each pixel point in the original echo image is converted into the geodetic vertical coordinate system, and the sonar data is uniformly calibrated, thereby improving the utilization rate and value of the sonar data.

[0111] Optionally, refer to Figure 5 As shown, the above step S401 includes:

[0112] S501, obtaining a polar angle correction formula corresponding to a polar angle and a polar diameter correction formula corresponding to a polar diameter in a polar coordinate system.

[0113] Exemplarily, the polar angle correction formula corresponding to the polar angle in the polar coordinate system is the following formula 1:

[0114]

[0115] And, the polar diameter correction formula corresponding to the polar diameter in the polar coordinate system is as follows:

[0116]

[0117] Among them, θ and θ corr Respectively represent the relative ship position angles before and after correction, r and r corr Respectively represent the relative ship position distance before and after correction, is the sonar transmit beam angle, τ is the beam pulse duration, and c is the speed of sound in water.

[0118] Therefore, the polar coordinate data of each pixel point can be spatially corrected by the above formula 1-formula 2 to correct the echo deviation caused by the sonar equipment.

[0119] S502 , inputting the polar angle in the polar coordinate data of each pixel point into a polar angle correction formula to obtain a corrected polar angle of each pixel point.

[0120] S503, inputting the polar diameter in the polar coordinate data of each pixel point into the polar diameter correction formula to obtain the corrected polar diameter of each pixel point.

[0121] S504 , obtaining corrected polar coordinate data of each pixel point based on the corrected polar angle of each pixel point and the corrected polar diameter of each pixel point.

[0122] Optionally, the polar angle in the polar coordinate data of each pixel point can be directly input into the polar angle correction formula, that is, the above formula 1, to obtain the corrected polar angle θ of each pixel point: corr ; and input the polar diameter in the polar coordinate data of each pixel point into the polar diameter correction formula, that is, the above formula 2, to obtain the corrected polar diameter r of each pixel point corr Then, based on the corrected polar angle and the corrected polar diameter of each pixel point, the corrected polar coordinate data of each pixel point is obtained, that is, (θ corr , r corr ).

[0123] Optionally, refer to Figure 6 As shown, the above step S103 includes:

[0124] S601, determining the channel color map of the original echo image under each channel.

[0125] Optionally, the original echo image may be processed to extract a channel color map of the original echo image under three channels, namely, the red primary color R, the green primary color G, and the blue primary color B. For example, Figure 7 is the channel color map under the red primary color R, Figure 8is the channel color map under the green primary color G, Fig. 9 It is the channel color map under the blue base color B.

[0126] S602: Determine the monotonically gradient echo intensity feature according to the channel color map of each channel.

[0127] The monotonically gradient echo intensity feature refers to that the echo intensity in the original echo image is monotonically gradient, that is, monotonically increasing or monotonically decreasing.

[0128] In one feasible method, the contrast of the channel color map under each channel can be obtained, that is, the contrast of the channel color map under the red primary color R; the contrast of the channel color map under the green primary color G channel and the contrast of the channel color map under the blue primary color B; then, the contrast of the channel color map under each channel is used to screen the channels with obvious color gradient changes in the echo area to determine the monotonically gradient echo intensity characteristics.

[0129] S603 , obtaining a plurality of echo data satisfying the color threshold according to the monotonically gradient echo intensity feature and a preset color threshold corresponding to the echo intensity.

[0130] The color threshold corresponding to the echo intensity is obtained based on experience. The echo intensity is mainly based on the common echo intensity of the target fish.

[0131] In this embodiment, the monotonically gradient echo intensity feature is compared with the color threshold corresponding to the echo intensity, a plurality of echo data that meet the range of the color threshold are screened, and the screened plurality of echo data are retained.

[0132] S604: Perform connected domain detection on multiple echo data that meet the color threshold, and obtain a denoised original echo image according to the connected domain detection result.

[0133] Optionally, a connected domain detection is performed on the selected multiple echo data, that is, a suitable connected domain threshold is given, such as 4 connected domains, 8 connected domains or 16 connected domains; the area smaller than the connected domain threshold is discarded, that is, the echo image that does not meet the characteristics of the target fish cluster is discarded, and the value is set to 0 to remove the noise echo such as waves. At the same time, the connected domain coordinate point area is detected. If the connected domain area includes the coordinates of the center of the ship position, this connected domain is discarded and the ship noise wake echo area is removed. The original echo image with only the target fish echo intensity signal is obtained, as shown in reference Fig.10 shown.

[0134] Optionally, refer to Fig.11 As shown, the above step S602 includes:

[0135] S1101, comparing the contrast of the channel color map under each channel, and taking the channel color map with the largest contrast as the main reference channel.

[0136] S1102, mapping and segmenting the main reference channel according to the preset echo intensity range corresponding to the shipborne sonar color scale to obtain a monotonically gradient echo intensity feature.

[0137] In this embodiment, reference Figure 7-Figure 9 As shown in the figure, by comparing the contrast of the channel color map under each channel, it can be obtained that the channel color map under the red channel is a channel color with obvious contrast gradient change. Therefore, the channel color map under the red channel is used as the main reference channel; then, according to the echo intensity range corresponding to the shipborne sonar color scale, the channel color map under the red channel is mapped and segmented to obtain the monotonically gradient echo intensity feature.

[0138] Optionally, in this solution, when denoising the original echo image, the acoustic intensity is screened in combination with the color sonar echo color scale, and the acoustic characteristic information of the corresponding fishery biological resources is extracted, thereby expanding the utilization method of fishery sonar data.

[0139] Optionally, refer to Fig.12 As shown, the above step S104 includes:

[0140] S1201, grayscale the denoised echo image to generate a target grayscale image.

[0141] In one feasible method, for example, a three-channel color map of the denoised echo image is extracted, namely, the color map of the red primary color channel, the color map of the green primary color channel and the color map of the blue primary color channel, and then the denoised echo image is gray-scaled according to the weighted average method: Gray = R*0.299+G*0.587+B*0.114 to generate a target grayscale map.

[0142] S1202, performing contour extraction according to the target grayscale image to obtain the pixel gradient and pixel gradient direction of each pixel in the target grayscale image.

[0143] In one achievable method, the contour of the echo area of ​​the target grayscale image is extracted using a pixel gradient operator to obtain the pixel gradient G(x, y) and pixel gradient direction α(x, y) of each pixel in the target grayscale image. The pixel gradient and the pixel gradient direction are respectively as follows:

[0144]

[0145] S1203. Filter out a plurality of target pixel points that meet the gradient threshold according to a preset gradient threshold and the pixel gradient and the pixel gradient direction of each pixel.

[0146] Exemplarily, the preset gradient threshold is [180, 200], that is, multiple target pixel points within the gradient threshold range are screened out.

[0147] In this embodiment, the pixel gradient of each pixel in the target grayscale image calculated above is compared with the gradient threshold, the pixel points falling within the gradient threshold range are retained, and the pixel points greater than the gradient threshold range or less than the gradient threshold range are discarded, so as to obtain multiple target pixel points that meet the gradient threshold.

[0148] S1204: Perform an opening and closing check on the multiple target pixel points to determine whether the multiple target pixel points form a closed pixel area.

[0149] S1205: If not, obtain multiple coordinate points on the shortest distance between the end pixel points that do not form a closed line, and perform interpolation processing on the multiple coordinate points on the shortest distance to obtain a fish school outline feature map.

[0150] In one feasible method, an open-close check is performed on a dot matrix composed of multiple target pixels to determine whether the dot matrix composed of multiple target pixels can form a closed pixel area; if so, a value is assigned to each target pixel; if not, multiple coordinate points on the shortest distance between the end pixels that do not form a closed line are obtained, and multiple coordinate points on the shortest distance are interpolated and connected to obtain a fish school contour feature map, thereby finally realizing the extraction of the edge contour features of the fish school echo signal. Fig.13 As shown, this is the extracted fish school contour feature map.

[0151] Optionally, refer to Fig.14 As shown, the above step S105 includes:

[0152] S1401, dividing the fish school outline feature map into multiple graphics.

[0153] S1402, determining the center of gravity and area of ​​each figure, and determining the coordinates of the center of gravity of the fish school based on the center of gravity and area of ​​each figure.

[0154] Exemplarily, the following formula 4-formula 5 may be used to calculate the coordinates (X, Y) of the center of gravity of the fish school:

[0155]

[0156]

[0157] Among them, the fish school contour feature map is a polygon, and the fish school contour feature map can be divided into n finite graphics, and the centroid coordinates of each graphic are determined as (G ix , Giy ) and the area is S i Therefore, the coordinates (X, Y) of the center of gravity of the fish school can be calculated by using the above formula 4-formula 5.

[0158] S1403, obtaining the number of pixels in the dot matrix and the number of pixels at the edge of the contour in the fish school contour feature map.

[0159] S1404, obtaining the cross-sectional area of ​​the school of fish according to the number of pixels in the dot matrix and the number of pixels at the edge of the contour.

[0160] For example, the cross-sectional area S of the school of fish may be calculated using the following formula 6:

[0161]

[0162] Among them, S is the area of ​​the dot matrix within the fish school outline, that is, the fish school cross-sectional area, n is the number of pixels in the dot matrix, and s is the number of pixels at the edge of the outline. Therefore, the above formula 6 can be used to calculate the fish school cross-sectional area S.

[0163] Optionally, refer to Fig.15 As shown, the above step S106 includes:

[0164] S1501. Obtain the longitude and latitude coordinates corresponding to the coordinates of the center of gravity of the fish school according to the pre-established second conversion relationship between the earth's longitude and latitude coordinate system and the vertical coordinate system and the coordinates of the center of gravity of the fish school.

[0165] Among them, the Earth's longitude and latitude coordinate system is a standard geographic coordinate system used to determine any location on the Earth. In the Earth's longitude and latitude coordinate system, two main coordinates are used: longitude and latitude.

[0166] Optionally, the fish school center of gravity coordinates (X, Y) calculated above are a coordinate point in a vertical coordinate system. Therefore, the fish school center of gravity coordinates (X, Y) can be converted into longitude and latitude in the earth's longitude and latitude coordinate system according to the second conversion relationship between the earth's longitude and latitude coordinate system and the vertical coordinate system. Exemplarily, the fish school center of gravity coordinates (X, Y) are (-336, 557), and after conversion, the latitude is 60.27°S and the longitude is 46.56°W.

[0167] S1502: Generate an echo latitude map of the original echo image in the earth's longitude and latitude coordinate system according to the second conversion relationship and the original echo image.

[0168] Optionally, the coordinates of each pixel in the original echo image may be converted into longitude and latitude format according to the second conversion relationship, and based on the converted longitude and latitude, an echo latitude map of the original echo image in the earth's longitude and latitude coordinate system may be obtained. Fig.16 As shown, this is the echo latitude map of the original echo image in the earth's longitude and latitude coordinate system.

[0169] Therefore, the original echo image converted into the vertical coordinate system is corresponded to the vertical coordinate system of the ship position under the longitude and latitude coordinates of the earth. The two coordinate system axes are overlapped according to the north azimuth deviation, the unit distance on the coordinate axis is converted, and the spatial distance scale is converted into the longitude and latitude scale to obtain the echo latitude map.

[0170] S1503, obtaining the azimuth and distance of the fish school relative to the ship according to the coordinates of the center of gravity of the fish school and the position point of the ship.

[0171] The vertical coordinate system is a coordinate system constructed with the ship's location as the origin. Therefore, the coordinates of the fish school's center of gravity and the ship's location (Lat ship , Lng ship ), and calculate the azimuth Angle and distance Distance of the fish school relative to the ship, as shown in the following formula 7-formula 8:

[0172]

[0173]

[0174] Among them, X ship and Y ship It represents the coordinates of the ship's position in the vertical coordinate system based on the ship's position, which is also the origin coordinate. The key is the conversion factor between the sonar range and the image pixel presentation.

[0175] Exemplarily, it is calculated that the azimuth of the fish school relative to the ship is -31.10° and the distance from the ship is 0.65 km.

[0176] S1504, adding the coordinates of the fish school's center of gravity, the cross-sectional area of ​​the fish school, the longitude and latitude coordinates corresponding to the coordinates of the fish school's center of gravity, and the azimuth and distance of the fish school relative to the ship to the echo latitude map to generate a geographically plotted nautical chart of the fish school.

[0177] In one achievable method, for example, the cross-sectional area of ​​the fish school is scale-converted to obtain the converted cross-sectional area, i.e., the target cross-sectional area; then, continue to refer to Fig.16As shown in the figure, the coordinates of the fish school's center of gravity, the longitude and latitude coordinates corresponding to the coordinates of the fish school's center of gravity, the azimuth and distance of the fish school relative to the ship (i.e., the azimuth of the ship's position and the distance from the ship's position), the north azimuth and the target cross-sectional area are added to the echo latitude map to generate a fish school geographic plotted nautical chart. In this way, it is possible to identify and plot the number of fish schools in the entire fishing ground, achieve the purpose of evaluating the amount of fish resources in the entire fishing ground, and then enable fishermen to quickly understand the size and distribution range of the detected fish resources, provide fishermen with real-time, accurate geographical location, fish information and other fishing information, and effectively improve the efficiency of ship fishing operations.

[0178] In another possible implementation, for example, referring to Fig.17 As shown, the coordinates of the fish school's center of gravity, the longitude and latitude coordinates corresponding to the coordinates of the fish school's center of gravity, the azimuth and distance of the fish school relative to the ship, the cross-sectional area of ​​the fish school and other information can also be added to the original echo image in the form of a label box, so that the fish school assessment information can be directly presented on the original echo sonar image, achieving a more accurate assessment of the amount of fish resources in the fishing ground, providing effective data support for distant-water fishery production, and having application and promotion value for distant-water fishery production.

[0179] Fig.18 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application, which can be installed on a computing device with data processing function on board a ship.

[0180] The electronic device includes: a processor 1801 and a memory 1802 .

[0181] The memory 1802 is used to store programs, and the processor 1801 calls the programs stored in the memory 1802 to execute the above method embodiment. The specific implementation method and technical effect are similar and will not be repeated here.

[0182] Optionally, the present invention also provides a program product, such as a computer-readable storage medium, comprising a program, which is used to execute the above method embodiment when executed by a processor.

[0183] In the several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0184] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0185] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0186] The above-mentioned integrated unit implemented in the form of a software functional unit can be stored in a computer-readable storage medium. The above-mentioned software functional unit is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (English: processor) to perform some steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (English: Read-Only Memory, abbreviated: ROM), random access memory (English: Random Access Memory, abbreviated: RAM), disk or optical disk and other media that can store program codes.

Claims

1. A method for assessing fish stock abundance based on fishery horizontal scanning sonar, characterized in that: The method comprises: Acquire echo data sent by a ship-borne horizontal scanning sonar device, the echo data including: an original echo image and polar coordinate data of each pixel point in the original echo image, the polar coordinate data including: a relative ship position angle and a relative ship position distance; According to the polar coordinate data of each pixel point in the original echo image, coordinate transformation is performed on the original echo image to obtain an original echo image in a vertical coordinate system; Performing denoising processing on the original echo image to obtain a denoised echo image; wherein the denoising processing is used to eliminate the sea wave signal and the wake reverberation signal in the original echo image; Performing edge feature detection on the denoised echo image to obtain a fish school contour feature map; Determine fish school characteristic parameters according to the fish school contour characteristic diagram, wherein the fish school characteristic parameters include: fish school center of gravity coordinates and fish school cross-sectional area; A geographically plotted nautical chart of the fish school is generated and displayed according to the fish school characteristic parameters and the original echo image.

2. The method according to claim 1, characterized in that The step of performing coordinate transformation on the original echo image according to the polar coordinate data of each pixel point in the original echo image to obtain an original echo image in a vertical coordinate system includes: Performing spatial distance compensation correction on the polar coordinate data of each pixel point to obtain corrected polar coordinate data of each pixel point; Taking the position point of the ship as the origin, a vertical coordinate system is established, and a first conversion relationship between the vertical coordinate system and the polar coordinate system is obtained; The corrected polar coordinate data of each pixel point is subjected to coordinate transformation according to the first transformation relationship to generate an original echo image in the vertical coordinate system.

3. The method according to claim 2, characterized in that The performing spatial distance compensation correction on the polar coordinate data of each pixel point to obtain the corrected polar coordinate data of each pixel point includes: Obtaining a polar angle correction formula corresponding to the polar angle and a polar diameter correction formula corresponding to the polar diameter in the polar coordinate system; Inputting the polar angle in the polar coordinate data of each pixel point into the polar angle correction formula to obtain the corrected polar angle of each pixel point; Inputting the polar diameter in the polar coordinate data of each pixel point into the polar diameter correction formula to obtain the corrected polar diameter of each pixel point; Based on the corrected polar angle of each pixel point and the corrected polar diameter of each pixel point, the corrected polar coordinate data of each pixel point is obtained.

4. The method according to claim 1, characterized in that: The denoising process is performed on the original echo image to obtain a denoised echo image, comprising: Determine the channel color map of the original echo image under each channel; Determining a monotone gradient echo intensity feature according to a channel color map under each of the channels; According to the monotonically gradient echo intensity feature and the color threshold corresponding to the preset echo intensity, a plurality of echo data satisfying the color threshold are obtained; Connected domain detection is performed on the plurality of echo data satisfying the color threshold, and the denoised original echo image is obtained according to the connected domain detection result.

5. The method according to claim 4, characterized in that Determining the monotonically gradient echo intensity feature according to the channel color map under each channel includes: Comparing the contrast of the channel color map under each of the channels, and taking the channel color map with the largest contrast as the main reference channel; According to the preset echo intensity range corresponding to the shipborne sonar color scale, the main reference channel is mapped and segmented to obtain the monotonically gradient echo intensity feature.

6. The method according to claim 1, characterized in that The step of performing edge feature detection on the denoised echo image to obtain a fish school contour feature map comprises: grayscale the denoised echo image to generate a target grayscale image; Perform contour extraction according to the target grayscale image to obtain pixel gradients and pixel gradient directions of each pixel in the target grayscale image; According to a preset gradient threshold and the pixel gradient and the pixel gradient direction of each pixel, a plurality of target pixel points that meet the gradient threshold are screened out; Performing an opening and closing check on the plurality of target pixel points to determine whether the plurality of target pixel points form a closed pixel area; If not, a plurality of coordinate points on the shortest distance between the end pixel points that do not form a closed line are obtained, and interpolation processing is performed on the plurality of coordinate points on the shortest distance to obtain the fish school outline feature map.

7. The method according to claim 1, characterized in that Determining fish school characteristic parameters according to the fish school contour characteristic map includes: Segmenting the fish school outline feature graph into a plurality of graphs; Determine the center of gravity and area of ​​each of the figures, and determine the coordinates of the center of gravity of the school of fish according to the center of gravity and area of ​​each of the figures; Obtaining the number of pixels in the dot matrix and the number of pixels at the edge of the outline in the fish school outline feature map; The cross-sectional area of ​​the school of fish is obtained according to the number of pixels in the dot matrix and the number of pixels at the edge of the contour.

8. The method according to claim 1, characterized in that The method of generating and displaying a geographically plotted nautical chart of a school of fish according to the characteristic parameters of the school of fish and the original echo image comprises: According to a pre-established second conversion relationship between the earth's longitude and latitude coordinate system and the vertical coordinate system and the coordinates of the center of gravity of the fish school, the longitude and latitude coordinates corresponding to the coordinates of the center of gravity of the fish school are obtained; Generate an echo latitude map of the original echo image in the earth's longitude and latitude coordinate system according to the second conversion relationship and the original echo image; According to the coordinates of the center of gravity of the fish school and the position point of the ship, the azimuth and distance of the fish school relative to the ship are obtained; The coordinates of the fish school's center of gravity, the cross-sectional area of ​​the fish school, the longitude and latitude coordinates corresponding to the coordinates of the fish school's center of gravity, and the azimuth and distance of the fish school relative to the ship are added to the echo latitude map to generate a geographically plotted nautical chart of the fish school.

Images