阅读说明：本技术 一种基于声学数据的海洋牧场海床遥测与识别方法 (Marine ranching seabed telemetering and identifying method based on acoustic data ) 是由 徐晓甫 曾祥茜 张博伦 郭彪 高燕 王宇 王硕 张雪 王宏 于莹 陈卫 房恩军 于 2021-01-14 设计创作，主要内容包括：本发明涉及一种基于声学数据的海洋牧场海床遥测与识别方法,包括以下步骤：步骤a.形成海洋牧场海床侧扫声纳声学图像；步骤b.形成海洋牧场海床多波束声学图像；步骤c.观察侧扫声纳声学图像和多波束声学图像的特征,识别人工鱼礁及设置典型海床样品采集站位,采集并记录海床类型；步骤d.构建海床类型与声学图像特征映射关系表；步骤e.对步骤d构建的映射关系表进行检验评价；步骤f.绘制海洋牧场海床类型空间分布图。本发明能够克服传统调查方法在海洋牧场中的局限性,解决高度异质性底栖生境中海床的识别与分类问题,为海洋牧场底栖生态系统、礁体淤积沉降及牡蛎礁修复等研究提供可靠数据。(The invention relates to a marine ranching seabed telemetering and identifying method based on acoustic data, which comprises the following steps: a, forming a side-scan sonar acoustic image of a sea bed of a marine ranching; b, forming a multi-beam acoustic image of the sea bed of the marine ranching; c, observing the characteristics of the side-scan sonar acoustic image and the multi-beam acoustic image, identifying the artificial fish reef, setting a typical seabed sample collection station, and collecting and recording the type of the seabed; d, constructing a mapping relation table of the seabed type and the acoustic image characteristics; e, checking and evaluating the mapping relation table constructed in the step d; and f, drawing a seabed type space distribution map of the marine ranching. The method can overcome the limitation of the traditional investigation method in the marine ranching, solve the problem of identification and classification of the seabed in the highly heterogeneous benthic habitat, and provide reliable data for researches on the benthic ecosystem of the marine ranching, reef sedimentation and settlement, oyster reef repair and the like.)

1. A marine ranching seabed telemetering and identifying method based on acoustic data is characterized by comprising the following steps:

a, collecting backscattering echo intensity data of a sea pasture seabed by using a side-scan sonar, integrally correcting and embedding the data through software to form a sea pasture seabed side-scan sonar acoustic image, and acquiring brightness characteristics and texture characteristics of the side-scan sonar acoustic image;

b, acquiring backscattering echo speed data of the sea pasture seabed by using a multi-beam depth sounder, integrally correcting and embedding the data through software to form a sea pasture seabed multi-beam acoustic image and obtain topographic relief characteristics of the multi-beam acoustic image;

c, observing the characteristics of the acoustic images of the marine ranch obtained in the step a and the step b, identifying the artificial fish reef by an artificial expert knowledge judgment method, setting a typical seabed sample collection station, collecting seabed samples and recording seabed types;

d, comparing the types of the artificial fish reef and the seabed sample with the seabed acoustic image characteristics of the marine ranch at the corresponding geographic position, and constructing a mapping relation table between the seabed types and the acoustic image characteristics;

e, according to the mapping relation table constructed in the step d, corresponding to each seabed type, randomly selecting a station in a marine ranch again, collecting seabed samples, carrying out inspection and evaluation on the mapping relation table constructed in the step d, constructing for multiple times when the overall accuracy is lower than a desired value and the overall accuracy is not lower than the desired value;

and f, performing acoustic inversion on the sea bed of the marine ranch by using the mapping relation table which is obtained in the step e and is checked to meet the requirement of the expected value, obtaining the integral sea bed type of the marine ranch, and drawing a marine ranch sea bed type space distribution map.

2. The marine ranch seabed telemetry and identification method based on acoustic data of claim 1, wherein: the data acquisition mode of the side-scan sonar in the step a is forward-dragging, GPS positioning information is imported in real time during the operation of the side-scan sonar, and the positioning precision is less than or equal to 1 m; the acquisition resolution of the side-scan sonar is less than or equal to 0.1 m; and in the side-scan sonar image processing process, bottom tracking operation is carried out to remove the interference of the water column.

3. The marine ranch seabed telemetry and identification method based on acoustic data of claim 1, wherein: b, when the multi-beam depth sounder is used for collecting data, a peripheral sensor is combined, and the peripheral sensor collects data of rolling, pitching, yawing, sound velocity, tide level and draft error and carries out calibration and calibration; when the multi-beam depth sounder works, GPS positioning information is imported in real time, and the positioning precision is less than or equal to 1 m; the acquisition resolution of the multi-beam depth sounder is less than or equal to 0.1 m.

4. The marine ranch seabed telemetry and identification method based on acoustic data of claim 1, wherein: the sampling mode of the seabed in-situ sample is to sample by using a box-type mud sampler, and the area of a box opening of the box-type mud sampler is more than or equal to 0.05m²(ii) a In the operation process, the GPS signal receiver is arranged above the box-type mud sampler and records the accurate longitude and latitude of the sampling station.

5. The marine ranch seabed telemetry and identification method based on acoustic data of claim 1, wherein: the acoustic image characteristics comprise side-scan image brightness, side-scan image textures and terrain relief, wherein the side-scan image brightness and the side-scan image textures are obtained from a side-scan sonar image, the description of the side-scan image brightness is divided into three categories, namely high category, middle category and low category, and the description of the side-scan image textures comprises point distribution, uniform continuity and alternate light and shade; the topographic relief is obtained from a multi-beam acoustic image, and the description of topographic relief includes significant head, flat, significant relief, slight relief, and waviness.

6. The marine ranch seabed telemetry and identification method based on acoustic data of claim 1, wherein: and e, randomly selecting at least 5 stations for collecting each seabed type.

7. The marine ranch seabed telemetry and identification method based on acoustic data of claim 1, wherein: the verification evaluation in step e is to evaluate the recognition effect through a confusion matrix.

8. The marine ranch seabed telemetry and identification method based on acoustic data of claim 1, wherein: and e, the value range of the overall accuracy expected value in the step e is 70% -90%.

9. The marine ranch seabed telemetry and identification method based on acoustic data of claim 1, wherein: and f, performing acoustic inversion in the step f, namely performing space superposition on the side-scan sonar and the multi-beam image of the marine ranch based on longitude and latitude information by using GIS software to identify the seabed types of different areas.

Technical Field

The invention belongs to the technical field of marine ranching habitat monitoring, and relates to a marine ranching seabed telemetering and identifying method based on acoustic data.

Background

The marine ranch as a new power for the transformation of the traditional fishery in China plays an important role in solving the prominent problems of marine habitat fragmentation, seawater eutrophication, fishery resource decline and the like, and is rapidly developed. The artificial fish reef is a carrier for constructing the marine ranch and is important content for restoring and constructing the habitat of the marine ranch. The artificial fish reef is put in, so that the speed and the strength of water flow are reduced, the nutrition supply capacity of the water body is improved, and a good living breeding place is provided for aquatic organisms, so that the yield and the quality of fishery resources are improved, the biological diversity is increased, and the ecological environment of the sea area is restored.

However, with the mass release of artificial fish reefs, the seabed of the marine ranch is transformed into a highly heterogeneous benthic habitat of reef nature, so that the traditional investigation methods such as fixed-point sampling and local trawl are limited in the marine ranch: 1) fixed-point sampling can provide detailed information of local small-area seabed, but in a highly heterogeneous marine ranch, the fixed-point sampling is not representative enough and is not suitable for obtaining large-range continuous information by an interpolation and extrapolation method; 2) the seabed trawl ecological survey cannot be normally carried out in a reef-dense marine ranch; 3) the adhesive shellfish tends to grow in an aggregating way around the artificial reef, and the traditional investigation method cannot accurately reflect the characteristic of massive and dense distribution of the shellfish. The research of marine ranch benthic ecosystems therefore faces many challenges.

The following patent documents relevant to the present application are found by search, and specific disclosures are as follows:

1. a marine ranch acoustic monitoring system and method (CN105785968A), the method comprising: step 101) generating at least one acoustic pulse signal, transmitting the generated acoustic pulse signal to a water body of a marine ranching through a transducer, and receiving echo signals of fish schools and other biological resources in the water body of the marine ranching; obtaining marine ranch information, wherein the marine ranch information comprises: temperature, salinity and seawater nutrient component; step 102) processing and information fusion are carried out on the obtained echo signals and the marine ranch information, and information of activity condition, density and biological resource amount of fish in the marine ranch is obtained in real time through statistics and analysis processing.

2. An actual measurement method (CN102986567B) of an ecological regulation and control range of an artificial fish reef area comprises the following steps: a. determining the existence of the artificial fish reef colony and the position of the core area thereof by using a hydroacoustic camera instrument, and giving accurate longitude and latitude coordinates of the boundary of the core area; the underwater acoustic camera is DIDSON; b. performing multi-site actual measurement on a CTD vertical section in a possible influence range of the artificial fish reef area, and determining the vertical arrangement number and the water layer depth of the thermometers according to the water temperature distribution rule of the section; c. vertically arranging thermometers above and below the thermocline for observation, and judging the flow field regulation scale of the reef area by observing the reduction degree of the surface-bottom layer temperature difference caused by the damage of the artificial fish reef group to the thermocline; d. stations are uniformly arranged on the plane for observation within the possible influence range of the artificial fish reef area, the more the stations are, the more accurate the actual measurement result is, and the more the stations are above 9 points; e. 3 times of observation during the large, medium and small tides are carried out on the time span, and the flow field regulation and control range of the reef area is measured and calculated along with the periodic change of the tides, so that the regulation and control range of the reef group is more accurately measured and calculated; f. and comprehensively analyzing the data of the observation stations within the time periods with the similar tide sizes, selecting and connecting the outermost stations regulated and controlled by the artificial fish reef area, and calculating the area to obtain the ecological regulation and control range of the reef area during the heavy tide or the medium tide or the light tide.

3. An evaluation method and a system (CN111325470A) for ecological environment bearing capacity of enclosed sea and surrounding sea areas are disclosed, the evaluation method comprises the following steps: the method comprises the following steps: searching and analyzing main influence factors of ecological environment bearing capacity of the enclosed sea and the surrounding sea area to obtain important factors with maximized influence degree, and establishing indexes of the influence factors; step two: data collection and data collection are performed based on the factors of influence. Step three: the collected data are sorted, and influence factors are subjected to data processing according to the sorted data; step four: and processing the collected data to generate a data model, calculating the environmental bearing capacity according to the model, and evaluating according to the calculated environmental bearing capacity data.

Through comparison of technical characteristics, the method disclosed by the patent document is different from the method disclosed by the invention, and the creativity and novelty of the invention application are not influenced.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a marine ranching seabed remote measurement and identification method based on acoustic data, which can be used for monitoring the marine ranching seabed in a large-scale, rapid, continuous and non-contact manner, realizes effective and accurate identification of ecological environment factors such as the type, distribution, area and the like of the marine ranching seabed, provides basic data for research of marine ranching benthic ecosystem, draws a marine ranching benthic habitat map and supports sustainable and healthy development of the marine ranching.

The technical problem to be solved by the invention is realized by adopting the following technical scheme:

a marine ranching seabed telemetering and identifying method based on acoustic data comprises the following steps:

a, collecting backscattering echo intensity data of a sea pasture seabed by using a side-scan sonar, integrally correcting and embedding the data through software to form a sea pasture seabed side-scan sonar acoustic image, and acquiring brightness characteristics and texture characteristics of the side-scan sonar acoustic image;

b, acquiring backscattering echo speed data of the sea pasture seabed by using a multi-beam depth sounder, integrally correcting and embedding the data through software to form a sea pasture seabed multi-beam acoustic image and obtain topographic relief characteristics of the multi-beam acoustic image;

c, observing the characteristics of the acoustic images of the marine ranch obtained in the step a and the step b, identifying the artificial fish reef by an artificial expert knowledge judgment method, setting a typical seabed sample collection station, collecting seabed samples and recording seabed types;

d, comparing the types of the artificial fish reef and the seabed sample with the characteristics of the seabed acoustic image of the marine ranch at the corresponding geographic position, and constructing a mapping relation table between the seabed types and the characteristics of the acoustic image;

e, according to the mapping relation table constructed in the step d, corresponding to each seabed type, randomly selecting a station in a marine ranch again, collecting seabed samples, carrying out inspection and evaluation on the mapping relation table constructed in the step d, constructing for multiple times when the overall accuracy is lower than a desired value and the overall accuracy is not lower than the desired value;

and f, performing acoustic inversion on the sea bed of the marine ranch by using the mapping relation table which is obtained in the step e and is checked to meet the requirement of the expected value, obtaining the integral sea bed type of the marine ranch, and drawing a marine ranch sea bed type space distribution map.

Preferably, the data acquisition mode of the side-scan sonar in the step a is forward-dragging, GPS positioning information is imported in real time during the operation of the side-scan sonar, and the positioning precision is less than or equal to 1 m; the acquisition resolution of the side-scan sonar is less than or equal to 0.1 m; and in the side-scan sonar image processing process, bottom tracking operation is carried out to remove the interference of the water column.

Preferably, the multi-beam depth sounder is used for collecting data in the step b, and a peripheral sensor is combined, and the peripheral sensor collects data of rolling, pitching, yawing, sound velocity, tide level and draft error, and calibrates the data; when the multi-beam depth sounder works, GPS positioning information is imported in real time, and the positioning precision is less than or equal to 1 m; the acquisition resolution of the multi-beam depth sounder is less than or equal to 0.1 m.

Preferably, the seabed in-situ sample is sampled by a box-type mud sampler, and the area of a box opening of the box-type mud sampler is more than or equal to 0.05m²(ii) a In the operation process, the GPS signal receiver is arranged above the box-type mud sampler and records the accurate longitude and latitude of the sampling station.

Preferably, the acoustic image features include side-scan image brightness, side-scan image texture and topographic relief, wherein the side-scan image brightness and the side-scan image texture are obtained from a side-scan sonar image, the description of the side-scan image brightness is divided into three categories, namely high, medium and low, and the description of the side-scan image texture includes dotted distribution, uniform continuity and alternate light and dark; the topographic relief is obtained from a multi-beam acoustic image, and the description of topographic relief includes significant head, flat, significant relief, slight relief, and waviness.

Preferably, at least 5 sites per seabed type are randomly selected for acquisition in step e.

Preferably, the verification evaluation in step e is to evaluate the recognition effect by means of a confusion matrix.

Preferably, the range of the expected value of the overall accuracy in the step e is 70% -90%.

Preferably, the acoustic inversion in the step f is to perform spatial superposition on the side-scan sonar and the multi-beam image of the marine ranch based on longitude and latitude information by using GIS software, and identify the types of the seabed in different areas.

The invention has the advantages and positive effects that:

(1) compared with the traditional survey method of 'fixed-point sampling and interpolation and extrapolation', the method can quickly and continuously acquire habitat information such as the type, form, distribution, area, micro-topography and the like of the sea bed of the marine ranching with high resolution and large range, and avoids errors caused by insufficient fixed-point sampling representativeness in the highly heterogeneous benthic habitat, so that the efficiency and the accuracy of the survey of the benthic habitat of the marine ranching are obviously improved;

(2) the marine ranching acoustic remote measuring method disclosed by the invention belongs to a non-contact investigation mode, successfully solves the problem that the traditional submarine trawl investigation method cannot work in a reef-dense marine ranching, avoids the artificial disturbance and damage of the traditional contact investigation method (fixed-point sampling and trawl investigation) to the benthic habitat, is beneficial to maintaining the originality and integrity of the benthic habitat, and ensures that the investigation mode and the final result of the benthic ecosystem of the marine ranching all fly over qualitatively;

(3) the method successfully solves the problem that shellfish distribution in the marine ranching cannot be accurately positioned, shellfish organisms are important proliferation objects of the marine ranching, block aggregation distribution is mostly presented in the marine ranching due to the characteristic of fixation overlapping growth of the shellfish organisms, and traditional fixed-point and trawl surveys are respectively carried out in a point-line mode and cannot accurately position the spatial distribution of the shellfish organisms; the acoustic telemetering method for the marine ranching develops the benthic ecological investigation technology from point to line to the surface, realizes the overall accurate detection of the spatial distribution of shellfish organisms, and provides basic data and effective support for the evaluation of shellfish resources in the marine ranching.

Drawings

FIG. 1 is a flow chart of marine ranch seabed telemetry and identification based on acoustic data in accordance with the present invention;

FIG. 2 is an acoustic image of a side-scan sonar of a Tianjin marine ranch in accordance with an embodiment of the present invention;

FIG. 3 is a multi-beam acoustic image of a Tianjin marine ranch in accordance with an embodiment of the present invention;

FIG. 4 is a diagram of a sampling site on the seabed of the Tianjin marine ranch in accordance with an embodiment of the present invention;

FIG. 5 is a view illustrating the identification and verification of the seabed in the Tianjin marine ranch according to the embodiment of the present invention;

FIG. 6 is a view of a spatial distribution of the seabed type in a Tianjin marine ranch in accordance with an embodiment of the present invention;

FIG. 7 is a graph of the correspondence of typical acoustic image features to a sample of the seabed in situ.

Detailed Description

The present invention will be described in further detail with reference to the following embodiments, which are illustrative only and not limiting, and the scope of the present invention is not limited thereby.

Referring to fig. 1, an embodiment of the present invention provides a marine ranch seabed telemetry and identification method based on acoustic data, including the following steps:

a, collecting backscattering echo intensity data of a sea pasture seabed by using a side-scan sonar, integrally correcting and embedding the data through software to form a sea pasture seabed side-scan sonar acoustic image, and acquiring brightness characteristics and texture characteristics of the side-scan sonar acoustic image;

b, acquiring backscattering echo speed data of the sea pasture seabed by using a multi-beam depth sounder, integrally correcting and embedding the data through software to form a sea pasture seabed multi-beam acoustic image and obtain topographic relief characteristics of the multi-beam acoustic image;

c, observing the characteristics of the acoustic images of the marine ranch obtained in the step a and the step b, identifying the artificial fish reef by an artificial expert knowledge judgment method, setting a typical seabed sample collection station, collecting seabed samples and recording seabed types;

d, comparing the types of the artificial fish reef and the seabed sample with the characteristics of the seabed acoustic image of the marine ranch at the corresponding geographic position, and constructing a mapping relation table between the seabed types and the characteristics of the acoustic image;

e, according to the mapping relation table constructed in the step d, corresponding to each seabed type, randomly selecting a station in a marine ranch again, collecting seabed samples, carrying out inspection and evaluation on the mapping relation table constructed in the step d, constructing for multiple times when the overall accuracy is lower than a desired value and the overall accuracy is not lower than the desired value;

and f, performing acoustic inversion on the sea bed of the marine ranch by using the mapping relation table which is obtained in the step e and is checked to meet the requirement of the expected value, obtaining the integral sea bed type of the marine ranch, and drawing a marine ranch sea bed type space distribution map.

Preferably, the side-scan sonar data acquisition in the step a needs a front-towing manner, so that wake flow interference caused by rear towing and ship bottom signal shielding caused by side towing are reduced to the maximum extent, and the quality of acoustic signals with back scattering intensity is ensured; GPS positioning information needs to be imported in real time during side-scan sonar operation, and the positioning precision needs to be less than or equal to 1m so as to meet the requirements of later-stage data analysis and image mosaic; the acquisition resolution of the side-scan sonar needs to be less than or equal to 0.1m so as to meet the requirement of seabed type identification precision; in the process of processing the side-scan sonar image, bottom tracking operation is required to be carried out, and interference of a water column is removed.

Preferably, when the multi-beam depth sounder is used for acquiring data in the step b, a peripheral sensor is required to be combined, and the peripheral sensor acquires error data such as rolling, pitching, yawing, sound velocity, tide level and draught and the like for calibration and calibration; when the multi-beam depth sounder works, GPS positioning information needs to be imported in real time, and the positioning precision needs to be less than or equal to 1m so as to meet the requirements of later data analysis and image mosaic; the acquisition resolution of the multi-beam depth sounder is required to be less than or equal to 0.1m so as to meet the requirement of seabed type identification precision.

Preferably, the seabed in-situ sample is sampled by a box-type mud sampler, and the area of a box opening of the box-type mud sampler is more than or equal to 0.05m 2; so as to ensure the success rate of shellfish seabed sample collection; in the operation process, a GPS signal receiver is arranged above a box type mud sampler, and a positioning signal is transmitted to a computer running GIS software in real time so as to accurately correct the longitude and latitude of a mud sampling station, avoid touching an artificial fish reef and record the real longitude and latitude of the sampling station; a differentiated field processing method is adopted for different types of seabed samples such as mud, shellfish and shellfish-mud mixtures, seabed type information is recorded for each sample, and a field photo is saved.

Preferably, the acoustic image features include side-scan image brightness, side-scan image texture and topographic relief, wherein the side-scan image brightness and the side-scan image texture are obtained from a side-scan sonar image, the description of the side-scan image brightness is divided into three categories, namely high, medium and low, and the description of the side-scan image texture includes dotted distribution, uniform continuity and alternate light and dark; the topographic relief is obtained from a multi-beam acoustic image, and the description of topographic relief includes significant head, flat, significant relief, slight relief, and waviness.

Preferably, at least 5 sites per seabed type are randomly selected for acquisition in step e.

Preferably, the verification evaluation in step e is to evaluate the recognition effect through a confusion matrix, wherein the confusion matrix is a form of representing the evaluation recognition precision and accuracy by using a matrix with n rows and n columns, and the seabed sample collected on the spot is compared with the given seabed type, and a consistent true value is given as 'yes' and an inconsistent true value is given as 'no'; the sea bed type identified by the acoustic data is compared with the given sea bed type, the consistent assigned identification value is 'yes', and the inconsistent assigned identification value is 'no', so that four basic indexes are obtained: the number (TP) corresponding to the identification value "yes"; the true value "yes", corresponding to the number of identification values "not" (FN); the number (FP) of true values "no" corresponding to the identification values "yes"; true value "not", corresponding to the number of recognized values "not" (TN)

The evaluation index adopts the integral accuracy ACC: the correct results of acoustic recognition account for the total number of validation samples:

preferably, the range of the expected value of the overall accuracy in the step e is 70% -90%; the expected value of the overall accuracy of this example is 85%.

Preferably, the acoustic inversion in the step f is to perform spatial superposition on the side-scan sonar and the multi-beam image in the marine ranch based on longitude and latitude information by using GIS software, so as to identify the types of the seabed in different areas.

In order to verify the effectiveness of the method, the embodiment of the invention relies on a national grade marine ranch demonstration area (Tianjin marine ranch) of the great spirit hall of Tianjin city, collects the backscattering intensity data and backscattering speed data of the sea bed of the Tianjin marine ranch through a side-scan sonar and a multi-beam depth sounder, and telemeters and identifies the type of the sea bed of the Tianjin marine ranch by combining with actually measured data of the sea bed field.

Step a, referring to fig. 2, this embodiment collects Tianjin marine ranch side-scan sonar data, and integrally corrects and inlays the data through GIS software to form a marine ranch seabed side-scan sonar acoustic image, and obtains the brightness characteristics and texture characteristics of the side-scan sonar acoustic image:

using Deep SwedishThe DE340 side-scan sonar produced by the company carries out integral detection on the seabed of the Tianjin marine ranch; the equipment frequency is 340kHz, the resolution is 10cm, and the requirement of seabed type identification is met; the field operation adopts a front-dragging mode, the sweep width is set to be 25 meters on both sides, and the interference of ship wake flow is reduced to the maximum extent. The space positioning information comes from a sub-meter differential GPS, the side-scan sonar data processing software adopts deep View FV 3.0 to convert the backscattering echo intensity data into side-scan sonar image brightness information, and the image brightness refers to the seabed hardness. And finally, integrally splicing and embedding the side-scan sonar data by utilizing ArcGIS 10.3 software to form a side-scan integral image of the Tianjin marine ranch, wherein the artificial fish reef on the side-scan image is clearly visible, and the seabed hardness heterogeneity of the marine ranch is obvious.

Step b, referring to fig. 3, the implementation collects Tianjin marine ranch multi-beam sounding data, integrally corrects and inlays the data through GIS software to form a marine ranch multi-beam acoustic image, and obtains topographic relief features of the multi-beam acoustic image:

the artificial fish reef area for side scanning and positioning is subjected to targeted detection by using a U.S. R2 Sonic 2024 model multi-beam depth sounder, 256 sound waves are emitted by the multi-beam depth sounder at one time, accurate water depth in a certain range at two sides of a flight line can be obtained, and the resolution reaches 10 cm. In the operation process, errors such as rolling, pitching, yawing, sound velocity, tide level and draught are calibrated and calibrated by combining a peripheral sensor, accurate marine ranch terrain data are obtained, grid deleting files are generated, and ArcGIS 10.3 software is led in for splicing and embedding to form a Tianjin marine ranch multi-beam integral image. In fig. 3, the color of the image changes from red to green to represent that the depth of water changes from small to large, and the image is displayed: 1) the water depth of the Tianjin marine ranch gradually increases from the northwest to the southeast; 2) the artificial fish reef has obvious water depth difference with the surrounding seabed, and the artificial fish reef can be accurately identified by using water depth data; 3) the terrain around the artificial fish reef has regional difference.

C, referring to fig. 4, observing the acoustic image characteristics of the side-scan sonar image and the multi-beam acoustic image, identifying the artificial fish reef by an artificial expert knowledge judgment method, setting a typical seabed sample collection station, collecting seabed samples and recording seabed types;

after the side-scan sonar and the multi-beam image are manually and preliminarily analyzed by an expert, the collection work of a seabed sample is expanded immediately, and 70 sampling stations are distributed in an area with typical image brightness and texture to ensure timeliness, representativeness and comprehensiveness of seabed data; the sampling device is 0.05m²And a box-type mud sampler, wherein each sample records seabed type information and retains a field photo. The acoustic characteristics of the artificial fish reef are obvious and unique, a box-type mud sampler cannot be used for direct sampling, and an artificial expert knowledge judgment method is adopted for identification and positioning.

D, comparing the types of the artificial fish reef and the seabed sample with the characteristics of the acoustic image of the seabed of the marine ranching at the corresponding geographic position, and constructing a mapping relation table between the seabed types and the acoustic image characteristics:

through comparison and analysis, 6 types of seabed are found in the Tianjin marine ranch: the acoustic image characteristics corresponding to the artificial fish reef, the silt type, the oyster mud type, the clam mud type and the crushed shellfish mud type are shown in table 1 and fig. 7, wherein the acoustic characteristics of clams in different areas of the marine ranch are different (see line 5 of fig. 7).

TABLE 1 sea floor type definition and Acoustic characterization

Step e, referring to fig. 5, according to the mapping relation table constructed in the step d, station positions are randomly selected again in the marine ranch corresponding to each seabed type, seabed samples are collected, the mapping relation table constructed in the step d is inspected and evaluated, the evaluation index adopts the overall accuracy, and when the overall accuracy is lower than a desired value, construction is carried out for multiple times until the overall accuracy is larger than or equal to the desired value;

in order to verify the accuracy of the recognition of the seabed of the Tianjin marine ranch in the embodiment, the recognition result is verified; the artificial fish reef and other 5 seabed types respectively use in-situ hoisting and fixed point sampling verification modes, the number of verification stations of each type is 5, and the expected value adopted in the embodiment is 85%.

The embodiment of the invention uses the confusion matrix to evaluate the recognition effect (table 2), and the result shows that the overall accuracy of the recognition method is 90 percent and is more than 85 percent of the specified expected value, so that the method can meet the research requirement of the benthic habitat of the Tianjin marine ranch. The identification effect of three types of the artificial fish reef, the oyster and the clam is the most excellent, and each judgment index is 100%; the type of the sludge is the second, the accuracy and specificity are 100%, and the sensitivity is 83.33%, which shows that the areas predicted to be the sludge are consistent with the actual conditions, and the individual scattered sludge areas cannot be effectively identified; the effect of the crushed shellfish mud mixing area and the oyster mud mixing area needs to be improved, and probably because the crushed shellfish mud and the oyster mud are relatively close in hardness and distribution area, the crushed shellfish mud and the oyster mud are not easy to distinguish on a sonar image, and errors are caused.

TABLE 2. recognition confusion matrix for sea bed in Tianjin ocean pasture

And f, referring to a sixth graph, performing acoustic inversion on the sea bed of the marine ranching by using the mapping relation table which is obtained in the step e and is checked to meet the requirement of the expected value, obtaining the integral sea bed type of the marine ranching, and drawing a marine ranching sea bed type space distribution graph.

Based on the verified seabed type acoustic image features, the embodiment of the invention divides and draws the spatial distribution of seabed types in the Tianjin marine ranch, and calculates the area of each type (table 3).

TABLE 3 seabed type distribution area of Tianjin ocean ranch

Compared with the traditional survey method of 'fixed-point sampling and interpolation and extrapolation', the method can quickly and continuously acquire habitat information such as the type, form, distribution, area, micro-topography and the like of the sea bed of the marine ranching with high resolution and large range, and avoids errors caused by insufficient fixed-point sampling representativeness in the highly heterogeneous benthic habitat, so that the efficiency and the accuracy of the survey of the benthic habitat of the marine ranching are obviously improved;

the marine ranching acoustic remote measuring method disclosed by the invention belongs to a non-contact investigation mode, successfully solves the problem that the traditional submarine trawl investigation method cannot work in a reef-dense marine ranching, avoids the artificial disturbance and damage of the traditional contact investigation method (fixed-point sampling and trawl investigation) to the benthic habitat, is beneficial to maintaining the originality and integrity of the benthic habitat, and ensures that the investigation mode and the final result of the benthic ecosystem of the marine ranching all fly over qualitatively;

the invention successfully solves the problem that the shellfish distribution in the marine ranch cannot be accurately positioned. Shellfish is an important proliferation object in a marine ranching, and due to the characteristic of fixation overlapping growth, massive aggregation distribution is mostly presented in the marine ranching, while traditional fixed-point and trawl surveys are respectively carried out in a point and line mode, and the spatial distribution of shellfish cannot be accurately positioned; the acoustic telemetering method for the marine ranching develops the benthic ecological investigation technology from point to line to the surface, realizes the overall accurate detection of the spatial distribution of shellfish organisms, and provides basic data and effective support for the evaluation of shellfish resources in the marine ranching.

Although the embodiments of the present invention and the accompanying drawings are disclosed for illustrative purposes, those skilled in the art will appreciate that: various substitutions, changes and modifications are possible without departing from the spirit and scope of the invention and the appended claims, and therefore the scope of the invention is not limited to the disclosure of the embodiments and the accompanying drawings.