156 results about "Acoustic propagation" patented technology

The invention provides an oil and gas equipment leakage acoustic characteristic intelligent identification early warning method and system, and relates to the technical field of oil and gas equipment safety monitoring, and the method comprises the steps: arranging a sonic sensor array to collect signals, calculating a wavefront propagation path, optimizing the wavefront curvature, carrying out the multi-scale decomposition of a sonic signal, and extracting time-frequency characteristics; and reconstructing a sound field by using an acoustic propagation function to determine a leakage point space coordinate. The method can accurately identify the acoustic characteristics of oil and gas equipment leakage, improves the leakage point positioning precision, achieves the early warning of leakage, and guarantees the safe operation of oil and gas equipment.

The invention relates to the technical field of underwater detection, and discloses an underwater comprehensive detection system. The system collects multi-dimensional acoustic data including sound wave reflection intensity, propagation time delay and frequency dispersion characteristics of a target water area through an underwater sonar array; dividing the detection area into a plurality of layered units according to a water attenuation coefficient and a substrate reflection characteristic of the acoustic data, and extracting an environment intrinsic parameter of each layered unit; constructing an acoustic propagation path model based on the environmental intrinsic parameters, and generating adaptive filtering parameters in combination with a preset noise suppression strategy; calling sonar array hardware configuration data, matching filtering parameters with an array beam forming mode, and calculating a detection sensitivity threshold value of each layered unit; and integrating the sensitivity threshold and the acoustic data, generating a three-dimensional acoustic characteristic spectrum of the target water area, and marking the space coordinates and confidence level of the abnormal area. The system can improve the comprehensiveness and accuracy of underwater detection, and meets the requirement of high-precision detection.

The invention provides an underwater positioning system combining sound ray propagation modeling and multipath interference suppression, which relates to the technical field of marine equipment and comprises a self-adaptive underwater sound sensing and environment cognition module, an environment self-adaptive sound ray propagation modeling module, a multipath suppression and direct wave extraction module and a multi-dimensional information fusion and self-adaptive positioning calculation module. The self-adaptive underwater sound sensing and environment cognition module is used for realizing multi-mode sensing and real-time environment feature recognition of underwater sound signals, and the environment self-adaptive sound ray propagation modeling module is used for constructing a dynamically updated sound wave propagation model and providing a propagation path and time constraint for positioning calculation; the multi-path suppression and direct wave extraction module is used for carrying out multi-path signal separation and extracting direct wave features with confidence marks, and the multi-dimensional information fusion and self-adaptive positioning calculation module is used for completing high-precision positioning calculation; according to the system, deep fusion of an environment model and signal processing can be realized, and the positioning precision and robustness of the underwater vehicle in a complex underwater sound environment are remarkably improved.

The invention relates to the technical field of underwater acoustic engineering and ocean exploration, in particular to a multi-channel underwater acoustic signal transmitting and measuring system and a signal processing method, which are used for solving the problems that the existing multi-channel underwater acoustic signal processing generally depends on fixed threshold detection or simple time sequence alignment, and the signal processing efficiency is low. The problem that residual vibration, local noise abrupt change or multipath reverberation is easily misjudged as an effective first arrival signal in a complex underwater environment due to the fact that the influence of the physical response characteristic of a transducer on emission time calibration is not considered and effective verification on whether a candidate arrival structure accords with a sound wave propagation physical rule is lacked is solved. According to the invention, a multi-channel energy time sequence and hydrophone space geometrical relationship is fused through an underwater sound propagation initial physical judgment module, a judgment mechanism is constructed based on distance-time consistency of sound propagation, and self-consistent verification is realized by combining a cross-channel arrival sequence and sound velocity constraint. And the accuracy, the robustness and the physical interpretability of the judgment of the effective launching time of the underwater sound are obviously improved.

The invention relates to the technical field of environmental noise monitoring, and discloses a road traffic noise intelligent monitoring and three-dimensional sound field reconstruction system, which comprises an acoustic sensor module, a data collection and storage module, a data analysis and evaluation module, a three-dimensional sound field construction and display module and a traffic flow feature library. According to the system, a differential geometry principle is adopted, a sound field is regarded as a Riemannian manifold with a local microstructure, and accurate description of an irregular sound field is realized through a curvature self-adaptive sound field manifold construction technology; introducing a covariant derivative in Riemannian geometry, and constructing a sound propagation model adapted to a complex road environment; and realizing hierarchical decomposition and reconstruction of the sound field by using a multi-scale analysis theory. According to the method, the sound source positioning precision and the calculation efficiency are improved, seamless analysis from microcosmic to macroscopic is realized, an innovative solution is provided for traffic and noise collaborative management, and intelligent traffic and environmental noise management are effectively supported.

The invention discloses a low-frequency sound propagation loss forecasting method suitable for a polar region sea area, and the method comprises the steps: building a two-dimensional ice layer model of a forecast sea area according to remote sensing data based on the setting that sea ice of the polar region sea area is a uniform elastic medium; calculating hydrological conditions of the ocean sound channel of the polar sea area; establishing a forecast sea area two-dimensional seabed model according to the seabed topography sediment database; an under-ice sound field model is constructed based on a three-dimensional cylindrical coordinate system, sound pressure from unit intensity sound sources with different sizes and depths to a receiving point in a forecast sea area is calculated through a frequency domain finite element method in combination with a PML technology, and sound propagation loss of a needed position is obtained through calculation. According to the method, the application limitation of traditional ray and normal wave theories under complex boundary conditions is broken through through a finite element method, a synergistic effect mechanism of actual ice layer parameter space change, submarine topography fluctuation and sound velocity profile gradient characteristics is systematically analyzed, and sound field modeling is more accurately carried out on different ice layers and submarine topographies in the Chukong sea region all year round; the influence of sound wave propagation is simulated.

The invention, which relates to the technical field of audio experience, discloses an immersive audio experience-oriented sound sound field orientation system comprising a position sensing module, a sound field modeling module, a characteristic sound wave generation module, an array control module and a space feedback adjustment module. The position and orientation information of a target user in a three-dimensional space is obtained in real time through a non-contact sensor, a real-time acoustic propagation model containing reflection surface distribution and material characteristics is constructed, a multi-channel acoustic signal is generated based on the model, a loudspeaker array is driven to produce sound through a beam control parameter set, and the sound transmission effect is achieved. According to the invention, the spatial focusing of the sound beam in the target direction is realized, the sound production delay and phase difference of each loudspeaker unit are dynamically adjusted based on the direction deviation information of the received sound pressure, and a closed-loop control path is formed. The method is suitable for various scenes such as virtual reality, intelligent cinemas and voice interaction.

The invention relates to the technical field of ocean engineering monitoring and underwater acoustic sensing, in particular to an underwater engineering structure anomaly detection and positioning method based on a subsurface buoy acoustic array. Comprising the following steps: establishing an equivalent coupling sound propagation model; a subsurface buoy system is arranged in a water body area above an underwater engineering structure, an acoustic receiving array is fixedly arranged on the subsurface buoy system, and time synchronization, array element space position calibration and channel gain calibration are carried out on the acoustic receiving array; when an abnormal acoustic event with a spatial consistent propagation characteristic is detected, the acoustic receiving array enters an enhanced working mode and outputs a multi-channel enhanced acoustic signal; and in the enhanced working mode, outputting a judgment result of whether an abnormal acoustic event occurs or not, and solving to obtain a position estimation value of the abnormal event in the axial direction of the structure and a corresponding positioning confidence interval. The method is suitable for online anomaly monitoring and accurate positioning of an underwater linear engineering structure with a known space trend in a complex marine environment.

The invention discloses a low-altitude airspace noise assessment method based on space grids, and belongs to the technical field of low-altitude unmanned aerial vehicle flight monitoring and assessment. The objective of the invention is to solve the problem of depicting capability of a sound field state in a three-dimensional airspace. According to the method, noise sensitive objects in a low-altitude flight airspace and an air route range are identified, and a noise sensitive architectural space database with noise limit value labels is established based on set differentiated noise limit values; carrying out three-dimensional space rasterization modeling on the target evaluation area, and carrying out environment parameter assignment on each space grid unit to obtain a structured three-dimensional space grid framework of the target evaluation area; establishing a sound propagation attenuation model considering the multi-physics field coupling effect, and calculating the sound pressure intensity and the maximum allowable sound source intensity of each structured three-dimensional space grid unit; constructing a multi-dimensional data combined three-dimensional noise database; and carrying out airspace availability analysis and flight path feasibility evaluation. According to the invention, three-dimensional visualization and layering and partition quantization of low-altitude airspace noise influence are realized.

A system for synchronizing and spatializing media, comprising client device and server device. A method for operation includes: tracking the real-time spatial coordinates of both devices via wireless sensors; synchronizing media playback using a timestamp-based protocol that compensates for network latency and clock offset; and applying directional audio filters, such as Head-Related Transfer Functions (HRTF), on the client device to render audio appearing to originate from server device's physical location. The method is further characterized by compensating for acoustic propagation and signal processing delays to ensure accurate spatiotemporal alignment. The system may be enhanced by a multimodal Al configured to perform operations such as real-time voice-preserving translation and the generation of synchronized, spatialized haptic feedback based on semantic event markers.

The invention provides a vector magnetic field detection method based on a surface acoustic wave magnetic field directivity model, and the method employs an external magnetic field to act on a magnetic sensitive film on a sound propagation path to generate a dynamic magnetoelastic coupling effect, modulates the propagation characteristics of surface acoustic waves, and carries out the decoupling of a sound signal, and obtains the magnetic field information. The response value of the sensor is influenced by the included angle between the direction of the external magnetic field and the anisotropic axis, so that the angle orientation of the sensor in the space and the size and direction of the magnetic field can be quantitatively calibrated by projecting the magnetic field to be measured in the space into a coordinate system of the sensor, and a surface acoustic wave magnetic field directivity model is constructed. The surface acoustic wave magnetic field sensing technology has the advantages of high sensitivity, quick response and the like, and the vector magnetic field detection method can realize the direction positioning function of a full-plane magnetic field and has important practical value in the application field of space vector magnetic field detection.

The invention discloses a broadband feature coupling and sparse low-rank joint imaging method, product and equipment, and belongs to the technical field of electrical equipment monitoring. The method comprises the following steps: S1, establishing a pure acoustic propagation model of a partial discharge sound source, and fusing partial discharge pulse waveforms and sound wave propagation characteristics; s2, constructing a physically constrained over-complete sparse dictionary based on the time domain damped oscillation of the partial discharge signal and the physical fingerprints with concentrated frequency domain and high energy; s3, constructing a joint optimization objective function by combining the characteristics of sparse time domain and low space rank of the partial discharge signal, and iteratively solving a space-time signal matrix; s4, designing a lightweight deep network fused with physical prior, and considering both precision and real-time performance; and S5, realizing data acquisition and imaging real-time processing based on a GPU stream processing architecture in combination with dual-threshold detection and pre-calculation optimization. The broadband transient characteristic and the space-time sparsity of the partial discharge pulse can be embedded into the imaging model, and a traditional general acoustic imaging frame is replaced.

The invention belongs to the technical field of underwater acoustic measurement, and relates to an indirect-coherent measurement method for the forward acoustic scattering target intensity of an underwater object. The method comprises the following steps: respectively carrying out background field measurement when an underwater object does not exist and target field measurement when the underwater object exists, and storing and recording receiving signals of an observation channel and a reference channel; based on the measurement signals of the background field and the target field, through time delay estimation and signal coherence subtraction processing, forward sound scattering signals of the underwater object are extracted; and calculating the forward sound scattering target intensity of the underwater object by using the extracted forward sound scattering signal based on the sound propagation loss estimation and the signal power. According to the method, after the forward sound scattering wave signal of the object is extracted, the definition formula of the target intensity in the sonar equation is directly used for measuring and calculating the forward sound scattering target intensity, the number of calculation links is small, and the calculation efficiency is high.

A method for determining at least one of a mud density or a standoff, includes determining, a short-spaced density, a long-spaced density, and a time of sound propagation between a tool body and a borehole wall. The method also includes determining, based at least in part on the short-spaced density and the long-spaced density, a formation density using a spine-and-rib-diagram. The method further includes determining a distance-to-spine value based on the short-spaced density, the long-spaced density, and the formation density. The method includes determining a mud density approximation, based at least on the distance-to-spine value. The method also includes determining a standoff approximation, based at least on the mud density approximation. The method further includes determining, based at least on the mud density approximation and the standoff approximation, at least one of a computed mud density or a computed standoff.

The application discloses a kind of sea surface convergence zone parameter calculation method and system based on sound propagation loss, method includes: propagation loss acquisition step: according to horizontal sound velocity profile variation data, seabed topography variation data and seabed sediment parameter, propagation loss data is obtained by sound propagation model;Convergence path acquisition step: based on propagation loss data, convergence path data and convergence zone quantity parameter are obtained by constant false alarm processing technique and connected domain technique;Convergence zone center point acquisition step: based on convergence path data, the position of convergence zone center point is determined by constant false alarm technique;Convergence zone boundary acquisition step: based on the gradient variation characteristics of convergence zone center point position combined with propagation loss data, the range boundary of the range boundary of convergence zone center point position is determined, and the detection and identification of underwater acoustic field convergence zone under complex marine environment are realized by the application.

The utility model discloses a cover body assembly which comprises a cover body, the cover body is provided with a gas inlet channel and a fuel gas channel, the two ends of the fuel gas channel are correspondingly provided with a gas inlet and a gas outlet, the gas inlet is communicated with the gas inlet channel, and the gas outlet is used for being communicated with a combustion cylinder. Wherein the fuel gas channel is provided with at least one section of narrowing part, the cross sectional area of the narrowing part is smaller than that of the fuel gas channel, and / or the fuel gas channel is provided with at least one section of expansion part, and the cross sectional area of the expansion part is larger than that of the fuel gas channel. Therefore, the change of acoustic impedance can be caused in the acoustic propagation process, and the reflection and interference phenomena of sound waves are generated, that is, the noise generated in the rapid flowing process of fuel gas can be reflected, interfered and the like at the narrowing part or the expansion part, so that the noise generated in the use process of the heat exchanger can be reduced. In addition, the utility model further discloses the heat exchanger with the cover body assembly.

The invention discloses a flow-induced noise integration method, device and equipment based on a finite element method and a storage medium, and relates to the technical field of noise integration, and the method comprises the steps: obtaining an aerodynamic noise source based on a sound source type and a time domain flow field file; transmitting an aerodynamic noise source from the fluid grid to the acoustic grid based on the acoustic grid file and a data mapping algorithm to obtain a time domain sound source; converting the time domain sound source into a frequency domain sound source based on a time-frequency conversion strategy; and constructing a numerical model based on the frequency domain sound source, and solving the numerical model to obtain a sound propagation result. The problems that in a traditional mixing method, due to the fact that a plurality of independent modules exchange large-scale intermediate data through a file system, the process is split, reading and writing are time-consuming, and user operation is tedious are solved, integrated solving of aerodynamic noise simulation from sound source extraction to sound field calculation is achieved, user operation steps are simplified, and user experience is improved. Therefore, on the premise that the calculation precision is guaranteed, the overall execution efficiency and the automation level of the simulation process are remarkably improved.

The invention relates to a regional ocean sound propagation field millisecond-level prediction method based on a deep neural network, and the method comprises the steps: constructing two factors which have the greatest influence on a sound propagation field for a target region: a sound velocity profile and a terrain; an environment information data set of an area sound propagation field is constructed by constructing an annual sound velocity profile of a target area node and building a large number of two-dimensional terrain models by extending around the node by 360 degrees, and the sound propagation fields of the area under different environment conditions are calculated by using a traditional sound field calculation model to serve as a training set; feature simplification parameters of the sound velocity profile and the terrain in each environment sample are extracted to serve as guide information of a corresponding sound propagation field, and a deep neural network is built to learn distribution rules of the sound propagation fields under different environment conditions in the area; and finally, the trained model can quickly predict the corresponding sound propagation field in the region according to different environmental condition characteristic batches.

The application relates to the technical field of virtual engine and discloses an immersive directional sound effect simulation optimization method and system based on a virtual engine. The method submits an acoustic ray tracing task to a hardware light tracing unit of a graphic processor at an acoustic solving rate lower than a graphic frame rate, accesses the same level of a bounding box acceleration structure as a graphic light tracing task, solves an effective sound propagation path according to a graphic material identification of a hit triangular facet, generates a path signature according to a sound source and the hit triangular facets successively passed through, and packs the path signature into an acoustic state snapshot for output; an audio rendering thread runs at an audio block rate higher than the acoustic solving rate, matches the snapshot and an active path set according to the signature, distinguishes a continuous path, a newborn path and a dying path, and respectively performs smoothing, fading in and fading out, and performs binauralization rendering on a sound source signal to obtain output binaural signals. The application solves the acoustic by reusing the graphic side acceleration structure, and continuously presents the directional sound effect without artifacts at a lower solving rate.

The invention relates to a measurement and inversion reconstruction method for a helicopter rotor sound radiation ball in an acoustic wind tunnel, and relates to the technical field of helicopter aeroacoustics wind tunnel test technology and sound target characteristics, and the method comprises the steps: measuring the noise radiated by a helicopter rotor in the acoustic wind tunnel through a hemispherical far-field noise measurement device; noise signals of the rotor in different directions are obtained, and a rotor sound radiation ball model is constructed; based on a sound propagation theory in a flow field, constructing a propagation model from the surface of the sound radiation ball model to the position of a microphone, and based on the influence of background noise, establishing a sound propagation equation from the surface of the sound radiation ball model to the microphone in the hemispherical far-field noise measurement device; and converting the sound propagation equation into solving a least square problem, solving to obtain sound source distribution on the surface of the sound radiation ball model, and reconstructing noise at any position of the far field of the helicopter rotor. The method can be suitable for reconstructing the helicopter rotor sound radiation ball in complex environments such as acoustic wind tunnels and high background noise, and practical research and application are carried out.

The invention relates to the technical field of environmental acoustics, discloses a road totally-enclosed sound barrier sound field prediction method and system, belongs to the field of environmental acoustics, and has very high practicability in sound field prediction and noise pollution evaluation of public road traffic noise after a totally-enclosed sound barrier is implemented. On the basis of the acoustic propagation principle, a new prediction method is provided for a road traffic noise source and a totally-closed sound barrier, a sound field is divided into two subsystems including a barrier internal space and an external space, and equivalent acoustic models of the two subsystems and a calculation method and recommendation parameters of the noise source sound power level are given respectively. According to the method, the sound environment of the high-rise building close to the urban road can be accurately predicted and calculated, and a basis is provided for noise pollution evaluation and control. And meanwhile, the method can be matched with a national standard method or commercial acoustic software for use, and has relatively high applicability.

The invention discloses a method for simulating sound propagation in a porous medium based on a QSGS-LBM, and the method comprises the steps: building a sound propagation physical model of an anisotropic porous medium based on the QSGS-LBM, and obtaining the density, pressure, speed and temperature distribution of a flow field during sound wave propagation; obtaining a density distribution function evolution equation and a temperature distribution function evolution equation based on the D2Q9 discrete velocity space; setting QSGS method parameters in the flow field area, and generating a porous medium model; obtaining a distribution function of each grid point after collision and migration, and applying boundary constraint conditions to the solid-liquid area based on the distribution function; and obtaining macroscopic variables on the grid points. According to the method, the iterative calculation time for multiple groups of porosity and structure parameters is remarkably shortened, the attenuation law of sound waves, sound pressure pulsation and temperature change caused by energy dissipation can be effectively captured, and the goodness of fit between a simulation result and a theoretical analytical solution is higher.

The invention discloses a CBN grinding wheel non-contact type grinding high-temperature alloy taper hole abrasion prediction method, and relates to the technical field of state monitoring and intelligent prediction in the precise grinding machining process. The method mainly comprises the following steps: calibrating a dynamic contact arc acoustic propagation model by using a system identification method to obtain dynamic geometric parameters, and constructing acoustic-vibration geometric coupling characteristics in combination with multi-mode signals in a grinding process; correcting the acoustic-vibration geometric coupling features by using a maximum mean difference algorithm and an adaptive window algorithm, training a wear prediction model by using the corrected acoustic-vibration geometric coupling features, and performing regression analysis on the corrected acoustic-vibration geometric coupling features by using the trained wear prediction model to obtain a prediction result. According to the grinding wheel abrasion prediction method for high-temperature alloy taper hole grinding, the adaptability, robustness and sensitivity of abrasion state characterization under complex variable working conditions can be improved.

The application discloses a method for constructing a sound convergence zone of a mesoscale eddy in the ocean based on a neural network, which comprises the following steps: obtaining an underwater sound speed field of the mesoscale eddy under a plurality of eddy parameters and calculating sound propagation loss under a plurality of sound source parameters; performing information coding on samples formed by the plurality of eddy parameters, the sound source parameters and the corresponding sound propagation loss to obtain training samples; building a neural network model, loading the training samples to train the neural network model to obtain an eddy-acoustic neural network model; inputting information coded from eddy parameters and sound source parameters of a target mesoscale eddy into the eddy-acoustic neural network model to predict sound propagation loss and obtain a predicted value of the sound propagation loss; and processing the predicted value of the sound propagation loss by a convergence zone calculation method to obtain sound convergence zone parameters of the target mesoscale eddy. The application aims to obtain the influence of the mesoscale eddy on the sound convergence zone and accurately obtain the variability characteristics of the convergence zone corresponding to the mesoscale eddy.

This invention discloses a sound velocity profile assimilation and inversion method and system based on dual physical data driving. The method includes: performing adaptive observation and sparse characterization of the sound propagation path to obtain the sparse characterization results; performing long-term noise cross-correlation calculation and passive time delay self-calibration to obtain the virtual sound source arrival time series after absolute time delay reference correction; performing constraint verification through a physical-data dual-driven, dual-stream coupled generative inversion network; acquiring a broadband electromagnetic response time series and performing cross-medium electromagnetic-acoustic joint inversion constraints to obtain a strongly constrained calibrated full-depth sound velocity profile; and performing ensemble Kalman filtering assimilation and uncertainty propagation based on POD order reduction. This invention can quantify the uncertainty of the inversion results. As a sound velocity profile assimilation and inversion method and system based on dual physical data driving, this invention can be widely applied in the field of underwater acoustic engineering technology.

The invention discloses a low-frequency broadband sound absorption metamaterial plate based on a curved neck Helmholtz resonator, and belongs to the technical field of ventilation pipeline sound absorption. According to the device, an upper cover plate, a lower bottom plate and a separation frame for connecting the upper cover plate and the lower bottom plate are jointly enclosed to form a sealed cavity. The interior of the cavity is divided into a public cavity arranged in the center and four curved neck Helmholtz resonance units which are distributed around the public cavity in a central rotational symmetry mode. And the internal part of the curved neck Helmholtz resonance unit comprises a suspended L-shaped embedded pipe and a suspended C-shaped embedded sub-cavity structure. By means of the nested coupling effect of the L-shaped embedded pipe and the C-shaped sub-cavity, the structure effectively prolongs the sound propagation path, and an additional absorption peak is introduced. On the premise that the total volume is not increased, adjustable low-frequency broadband efficient sound absorption under the deep sub-wavelength scale is achieved, the structure is smooth, the thickness is small, geometric parameters are independently adjustable, and the influence on fluid resistance is small, and the engineering problem that low-frequency noise in a narrow space (such as a ventilation pipeline) is difficult to eliminate is effectively solved.

The present application relates to a kind of acoustic wind tunnel inside helicopter rotor sound radiation sphere measurement and inversion reconstruction method, it is related to helicopter aerodynamic acoustics wind tunnel test technology and acoustic target characteristic technical field, include: in acoustic wind tunnel using hemispherical far-field noise measuring device measurement helicopter rotor radiated noise, obtain the noise signal of different azimuth of rotor and construct rotor sound radiation sphere model;Based on the sound propagation theory in flow field, construct the propagation model of the surface of sound radiation sphere model to microphone position, and based on the influence of background noise, establish the sound propagation equation of the surface of sound radiation sphere model to microphone in hemispherical far-field noise measuring device;Sound propagation equation is converted to solve least square problem, and the sound source distribution of the surface of sound radiation sphere model is obtained, and the noise of helicopter rotor far field arbitrary position is reconstructed.Can be applied to in acoustic wind tunnel, high background noise and other complex environments reconstruct helicopter rotor sound radiation sphere, carry out practical research and application.

The application relates to the technical field of active sonar detection, in particular to a transmission waveform selection method for target wake field disturbance detection, which comprises the following steps: applying uniform engineering constraints to selected engineering realizable waveforms to construct a candidate transmission waveform set of a detection system; equivalent the influence of target wake field disturbance on sound propagation to a time delay perturbation process of multi-path propagation, and establishing a target wake field disturbance sensitivity model accordingly; using the target wake field disturbance sensitivity model, calculating the sensitivity indexes of each candidate transmission waveform in the candidate transmission waveform set and sorting, taking the candidate transmission waveform with the largest sensitivity index as the optimal transmission waveform most suitable for target wake field detection; instructing the transmission end of the detection system to transmit a sound wave signal based on the optimal transmission waveform. The method can improve the observability of weak propagation time-varying characteristics caused by wake disturbance, and make the selection of the transmission waveform have stronger explainability and scene adaptation ability.

The application provides a sonar image three-dimensional reconstruction method based on target shadow and gray scale, which comprises the following steps: Step 1, converting the original sonar image into a gray scale image; Step 2, carrying out denoising treatment on the image; Step 3, carrying out shadow edge calibration; Step 4, segmenting a target region; Step 5, eliminating small target regions; Step 6, solving the pitch angle of the target region; and Step 7, reconstructing the target region. The application uses the multi-beam forward-looking sonar imaging principle as a research object, analyzes the transmission, reflection and reception process of sound waves, realizes a reverse reasoning using sound propagation, and obtains the three-dimensional reconstruction of the target object in the sonar image.

The invention provides a machine learning underwater sound propagation prediction method based on parabolic equation hard constraint, and the method comprises the following steps: 1), building a PE model of underwater sound propagation, and expressing the sound propagation as an initial value problem suitable for stepping solving; 2) constructing a recurrent neural network architecture which comprises a PE constraint module and a network correction module; 3) acquiring an underwater sound field data set in an initial distance range as training data; 4) only training the correction network module by using the training data, and learning a correction residual error between the physical model and a real sound field; and 5) recursively predicting sound fields of one or more extrapolation areas outside the initial distance range in a stepping manner by using the trained model starting from a known sound field. Through the unique architecture of'hard constraint physics + data-driven correction ', physical consistency is fundamentally ensured, error accumulation is remarkably inhibited, and high precision and stability superior to those of an existing soft constraint model are shown on a long-distance extrapolation task.