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57 results about "Acoustical holography" patented technology

Acoustic holography

A method of performing near- field acoustic holography comprises the following steps. Establishing (102) acoustic data representing a set of near-field acoustic holography measurements at a first set of positions. Extrapolating (204) acoustic data using a model-based extrapolation to obtain extrapolated acoustic data relating to a plurality of positions outside the aperture. Applying a spatial frequency transform to the padded acoustic data to obtain data in a spatial frequency domain. Propagating (110) the Fourier transformed acoustic data. Applying (112) a regularization in a wavenumber domain. Performing (114) an inverse spatial frequency transform.
Owner:STICHTING VOOR DE TECH WETENSCHAPPEN +1

Statistically optimal near-field acoustical holography used for visual recognition of air-conditioner noise sources and operation method thereof

InactiveCN101556187APosition discriminationDiscriminant sizeSubsonic/sonic/ultrasonic wave measurementVisual recognitionData treatment
The invention provides statistically optimal near-field acoustical holography used for visual recognition of air-conditioner noise sources and an operation method thereof. The operation method comprises the followings: determining the positions, frequency characteristics and distribution ranges of the noise sources, and distance between microphones on microphone arrays, number, sample rates and number of sampling points of microphones; calibrating arrayed microphones; collecting data; recording sound pressure data; processing the sound pressure data; reading the processed data and finally entering noise source recognition procedures. By the invention, complex sound pressure on reconstructive surfaces and vibration velocity of surface particles can be calculated directly via linear superposition of the complex sound pressure on a holographic plane in a spatial domain, thus essentially overcoming window effects and wraparound errors existing in near-field acoustical holography and avoiding the problems brought about by the demand of a large number of microphones by near-field acoustical holography, such as low reconstruction efficiency of sound fields and costly cost of measuring systems, etc. The invention is characterized by small number of demanded microphones, low measuring cost and high reconstruction efficiency of the sound fields.
Owner:MIDEA GRP CO LTD

Method for re-establishing moving sound source by adopting moving equivalent source method

InactiveCN101539455AEliminates the effects of the Doppler effectRealization of sound field reconstructionSubsonic/sonic/ultrasonic wave measurementEquivalent source methodSound sources
A method for re-establishing a moving sound source by adopting a moving equivalent source method is characterized in that the method comprises the following steps of measuring Doppler effect-contained sound pressure data in a moving sound source radiation sound field; establishing a transmission relationship between vibration speed and radiation sound pressure under Doppler effect-contained measured sound pressure and sound source static situation by the moving equivalent source; removing the influence of the Doppler effect according to the transmission relationship; and realizing the positioning identification and sound field re-establishment of the moving sound source. The moving sound source applicable to the method can be any shapes including plane, cylindrical surface or spherical surface; and the method is developed on the basis of a near-field acoustical holography reconstruction algorithm based on the equivalent source, has good computation stability, high computation precision and simple execution.
Owner:HEFEI UNIV OF TECH

Sound field separating method based on single-surface measurement and local acoustical holography method

The invention relates to the field of noise, in particular to a sound field separation and reconstruction method applicable to sound field separation and reconstruction of large sound sources. The sound field separation and reconstruction method comprises the following steps of: acquiring sound pressure and normal particle vibration velocity on a measuring surface; performing zero filling extension on the measuring surface positioned between two sound sources; acquiring transfer matrixes between the extended measuring surface and surfaces of the two sound sources, namely sound source faces; building a transitive relation between the sound pressure and the normal particle vibration velocity on the measuring surface; and acquiring the sound pressure and the normal particle vibration velocity of the first sound source face and the sound pressure and the normal particle vibration velocity of the second sound source face. A sound field is separated and reconstructed by using the single-measurement-surface and local near-field acoustical holography method. The sound field separation and reconstruction method has the characteristics of simplicity, short calculation time and high calculation efficiency, and can be widely applied to the measurement of near-field acoustical holography, the measurement of material reflecting coefficients, the separation of scattering sound fields and the like of large-size sound-source sound fields.
Owner:三亚哈尔滨工程大学南海创新发展基地

Piezoelectric underwater sound transducer acoustic radiation mode measurement method and system

InactiveCN103743469AAddressed issue where reconstruction accuracy was often much lower than acoustic pressure reconstruction accuracyPrevent leakageSubsonic/sonic/ultrasonic wave measurementAuditory radiationSound pressure
The invention provides a piezoelectric underwater sound transducer acoustic radiation mode measurement method and system based on combination near-field acoustical holography. In the method, the combination near-field acoustical holography is utilized to reestablish sound field, sound pressure and radiation surface vibration velocity; on the basis of an acoustic radiation operator matrix obtained based on measurement data and with the sound field radiation theory being combined, the acoustic radiation power of a piezoelectric underwater sound transducer is expressed to be a positive definite quadric form; and positive definite and conjugate performance of the matrix are utilized to obtained an acoustic radiation mode of the structure. The system comprises a glass water tank, an industrial control computer with PXI bus, a transducer excitation module based on the PXI bus, a sound pressure and vibration velocity acquisition module and a three-dimensional motion platform. The method and system in the invention break the limitation that acoustic radiation mode in the current complex underwater structure can only be solved numerically, provide a new idea for research on the piezoelectric underwater sound transducer, and also provide basis for structure optimization of the piezoelectric underwater sound transducer.
Owner:XI AN JIAOTONG UNIV

Movable noise source recognizing method based on local near field acoustical holography method

The invention belongs to the field of noise like sound field reconstruction and visualization, and particularly relates to a movable noise source recognizing method based on a local near field acoustical holography method. The movable noise source recognizing method includes the steps that sound pressure on a measuring plane H is measured; Doppler effect removal is carried out on the sound pressure obtained through measuring to obtain sound pressure, not containing the Doppler effect, on the measuring plane H; zero padding expansion is performed on the sound pressure on the measuring plane H to obtain sound pressure on a measuring plane H+; a transmission matrix between the sound pressure on the measuring plane H+ and the sound pressure on a reconstruction plane S is calculated; the sound pressure on the reconstruction plane S is solved. Based on the local near field acoustical holography method, the movable noise source recognizing method has the advantages of being simple in calculation, short in calculation time, high in calculation efficiency and the like compared with a traditional method.
Owner:HARBIN ENG UNIV

Method for recognizing three-dimensional coordinates of sound sources via planar arrays

The invention provides a method for recognizing three-dimensional coordinates of sound sources via planar arrays. The method comprises the steps of carrying out planar sound field reconstruction at different distances by taking meshed mesh points of a three-dimensional space as reconstruction points via a beam forming method on the basis of a spherical wave sound field model, comparing the output values of beam formers on different reconstruction surfaces along the distance direction (Z direction), and determining the Z-axis coordinate corresponding to the maximum output value as the distance of the sound sources. The method provided by the invention has the advantages of being applied to the two-dimensional arrays, recognizing the three-dimensional coordinates of the sound sources and being directly applied to the existing planar array acoustical holography equipment which is only capable of recognizing the two-dimensional coordinates of the sound sources; and the effectiveness and the reliability of the method are proved by tests.
Owner:ZHEJIANG UNIV OF TECH

Panel acoustic contributions examination

A system for analyzing noise sources correlates the sound pressure level value at any field point to the acoustic energy directly flowing out of any individual panel of a vibrating structure. This acoustic energy flow or acoustic intensity depicts how sound radiates and in which direction a sound wave propagates in the field. Therefore, the result represents a true contribution of an individual panel to an acoustic field. The acoustic intensity on the surface of a vibrating object is reconstructed by the Helmholtz equation least squares (HELS) based nearfield acoustical holography (NAH). The acoustic intensity is utilized to establish correlations between user-designated panels and the SPL value at any field point. With this information users can rank the order of contributions from individual panels of any vibrating structure to an acoustic field. These order ranking and panel contribution analyses help engineers to come up the best strategy to tackle various noise issues in the most cost-effective manner. The method is applicable to both interior and exterior regions.
Owner:WAYNE STATE UNIV

Method of determining the sound pressure resulting from a surface element of a sound emitting device

ActiveUS20070068255A1Rigid surface is avoidedMeet the blocking requirementsVibration measurement in solidsWeighing apparatus using counterbalanceSound sourcesAcoustic transfer function
A three-dimensional array (10) of microphones (M) is used to determine the three-dimensional sound field above a surface element (ΔS) of a sound emitting surface (S), and the air-particle velocity (un) at the surface element (ΔS) is determined using Near-Field Acoustical Holography (NAH). A volume velocity sound source (11) is used to emit a volume velocity (Qv) in a listening position, and the array (10) of microphones (M) is used to determine the resulting three-dimensional sound field above the surface element (ΔS), and using NAH the resulting sound pressure at the surface element (ΔS) is determined. The acoustic transfer function (H) between the surface element (ΔS) and the listening position is assumed to be reciprocal and is determined as the ratio of the resulting sound pressure at the surface element (ΔS) to the volume velocity (Qv). The sound pressure in the listening position resulting from the surface element (ΔS) is determined as Δp=H.(un. ΔS).
Owner:BRUEL & KJAER SOUND & VIBRATION MEASUREMENT

Array bracket

The invention belongs to the technical field of engine pedestal test, and in particular relates to a near field acoustical holography test bracket structure used in engine pedestal test environment. The bracket comprises fixing members and connecting members, the adjacent fixing members are connected by the connecting members, and the fixing members are provided with supported holes. As known fromthe above technical scheme, in the invention, microphones can be put into the supported holes of the fixing members which are connected by the connecting members, and the number and structure of thefixing members and the connecting members can be determined according to the concrete requirement of the test, thus, the invention has simple structure and changeable test structure, therefore, the test effect is better.
Owner:CHERY AUTOMOBILE CO LTD

Measuring method of ground reflection noise source

The invention provides a simple and effective measuring method of a ground reflection noise source, which has low measuring cost. The measuring method comprises the following steps: A, supporting a finished automobile by hoisting equipment; B, stabilizing the operation working condition of the automobile at the state to be tested; C, horizontally placing a baffle board below an automobile body, wherein a gap between the baffle board and a chassis is same with a gap between a baseboard and the finished automobile when the finished automobile is naturally placed on the ground; translating the baffle board along the length direction of the automobile body; meanwhile, utilizing noise measuring equipment arranged in an automobile chamber to measure noise in the automobile chamber; according to the acoustic pressure level characteristic of attention noise in the automobile when the baffle board is on different positions, determining the main noise resource of noise reflected into the automobile by the baffle board. The measuring method of the ground reflection noise source of the invention can quickly measure the main noise resource of noise reflected into the automobile from ground by simple equipment. Compared with the traditional phonometry or acoustical holography method which is used for determining acoustic source, the measuring method of the invention has simple operation and low measuring cost.
Owner:CHERY AUTOMOBILE CO LTD

Near-field acoustical holography method based on combinatorial optimization regularization method

ActiveCN109764956ASuppresses measurement errorsFully demonstrate effectivenessSubsonic/sonic/ultrasonic wave measurementObservational errorSound pressure
The invention discloses a near-field acoustical holography method based on a combinatorial optimization regularization method. The sound pressure at each point measured on a holographic surface is used, based on a statistical optimal cylinder near-field acoustical holography method, the truncated singular value and standard Tikhonov combinatorial optimization regularization method are used for selected wave number vectors to suppress measurement errors of the wave number vectors caused by the noise and random errors, and that is the combinatorial optimization regularization method; by using the combinatorial optimization regularization method and a GCV method, a superposition coefficient matrix and the sound pressure at each point measured on the holographic surface are obtained, and a sound field on the surface of shell structure equipment can be obtained by expressing the sound pressure at each point on the surface of the shell structure equipment as linear superposition of the conformal measurement surface sound pressure; and effectiveness of the near-field acoustical holography method in shell radiation noise analysis is fully demonstrated, the near-field acoustical holographymethod is suitable for the cylindrical shell structure, a sound field of a cylindrical underwater vehicle is displayed visually, and thus the magnitude and distribution of a radiated sound field can be seen intuitively, so that important theoretical significance and engineering application values are achieved.
Owner:XI AN JIAOTONG UNIV

Global active noise reduction method for rotor craft

The invention discloses a global active noise reduction method for a rotor craft. The method comprises the steps of collection of noise sound pressure signals at rotor measuring points, rotor noise acoustical hologram sound field prediction, rotor noise reverse sound field reconstruction and adaptive sound field adjustment based on optimal phase search. Compared with an existing passive and active noise reduction method, the global active noise reduction method based on acoustical holography and sound field reconstruction does not need to change a rotor wing type or introduce a complex mechanical structure, and only needs to arrange a plurality of measuring devices and secondary sound sources around a machine body, so that the increase of system complexity and cost is avoided, and the method has higher practical value and a better noise reduction effect. In addition, compared with traditional rotor wing noise finite point local noise reduction based on a self-adaptive filtering algorithm, the noise reduction method based on acoustical holography and sound field reconstruction is better in consistency, and can realize real rotor wing global noise reduction.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Transformer vibration noise source positioning system and method

The invention discloses a transformer vibration noise source positioning system and method, and relates to a vibration noise source positioning method. The transformer vibration noise source positioning system includes a spiral array sensor, a guide rail, a signal processor, a computer and a traction motor, wherein the spiral array sensor utilizes a wave beam shaping algorithm and a near field acoustical holography algorithm to identify the transformer vibration noise source, and at the same time an optical camera shoots the real-time images of a transformer; a classical transfer function database of each voltage class transformer is arranged in a path transfer analysis module, and the path transfer analysis module also includes a crosstalk elimination module, and can solve coupling of thetransfer path; and the final result is stored in a computer in a data form and an ultrasonogram mode. The transformer vibration noise source positioning system and method can be applied to a transformer in each voltage class and each operation condition.
Owner:ELECTRIC POWER RES INST OF GUANGXI POWER GRID CO LTD

Porous acoustical holography method for sound field identification

The invention relates to a porous acoustical holography method for sound field identification. The porous acoustical holography method comprises the following steps: 1) designing and processing single microphone arrays, and seeking an optimal arrangement form of the porous microphone arrays in a restricted space through simulating calculation; 2) arranging n single microphone arrays in the actual testing space according to the optimal arrangement form of the porous microphone arrays obtained in the step 1); 3) utilizing the spatial porous microphone arrays to acquire sound pressure signals of a target sound source, selecting a sound field reestablishing surface between the target sound source and the porous microphone arrays, performing porous sound holographic sound field reestablishing on the target sound source, and obtaining the sound field pattern of the target sound source, wherein the main lobe center position in the sound field pattern is the estimated position of the target sound source. The porous acoustical holography method disclosed by the invention can be particularly widely applied to noise control of large construction machinery, and automobiles, trains and airplanes moving rapidly.
Owner:TSINGHUA UNIV

Near-field acoustical holography reconstruction method based on equivalent source method

The invention provides a near-field acoustical holography reconstruction method based on an equivalent source method. A radiated sound field of a vibration radiator is considered to be formed by a superposition of sound fields generated by a series of equivalent sources arranged in the radiator. Source intensity of the equivalent sources can be obtained by normal velocity matching of the radiator surface. Thus, sound radiation is calculated. The near-field acoustical holography reconstruction method based on the equivalent source method is suitable for near-field acoustical holography of sound sources of arbitrary shapes and is adopted to raise computational efficiency and computational accuracy.
Owner:GUANGXI UNIVERSITY OF TECHNOLOGY

Method for detecting non-stationary acoustic sources based on near-field acoustical holography technology

The invention discloses a method for detecting non-stationary acoustic sources based on a near-field acoustical holography technology. The method includes the following steps that (1), according to the acoustic emission phenomenon of the non-stationary acoustic sources, a cylindrical surface-spherical surface non-conformal surface acoustical holography experimental model is established according to the near-field acoustical holography technology; (2), the number of detection points and the number of reconstructed spherical surface nodes are set for single acoustic sources on the experimental model, simulation experiment analyzing is performed, and parameters are selected; (3), according to the parameter selection result of single acoustic source simulation, double acoustic sources are reconstructed, and the effectiveness of the method is verified; (4), through analyzing experimental data, the selection rule of the distances from a particular solution point source to the nodes on a reconstructed spherical surface and main parameters affecting reconstruction precision are fictional; (5), according to optimal simulation experiment parameters, an acoustical holography experiment system is designed. The non-stationary acoustic source is positioned through the near-field acoustic holography technology, the position and the characteristics of the non-stationary acoustic source can be accurately measured, and therefore convenience is provided for effective control over noise.
Owner:GUANGXI UNIVERSITY OF TECHNOLOGY

Near-field acoustical holography reconstruction method based on Fourier transformation and source strength simulation technology

The invention provides a near-field acoustical holography reconstruction method based on the Fourier transformation and source strength simulation technology. The near-field acoustical holography reconstruction method based on the Fourier transformation and source strength simulation technology comprises the steps that continuous simple sources are arranged on a rectangular virtual source surface, and a source strength function is a three-dimensional free space Green function; double Fourier series expansion is carried out on an unknown source strength density function, and a sound pressure expression is deduced; expressions of the sound pressure on measuring points on a holographic surface are deduced through quick Fourier transformation and inverse transformation calculation, and a non-homogeneous linear equation set which uses a Fourier series expansion coefficient as an unknown term and the sound pressure as a constant term is formed through arrangement; the Fourier series expansion coefficient is obtained by solving the non-homogeneous linear equation set through a generalized inverse matrix, the Fourier series expansion coefficient is substituted into a reconstruction formula in a back substitution mode, the expression of the sound pressure on any field point in a radiation field is obtained, and reconstruction and prediction of the whole space sound field are achieved. According to the near-field acoustical holography reconstruction method based on the Fourier transformation and source strength simulation technology, implementation is easy, the calculating speed is high, limitation cannot be caused by the limited hole diameter, and the near-field acoustical holography reconstruction method is applicable to sound sources with any shapes.
Owner:GUANGXI UNIVERSITY OF TECHNOLOGY

Digital detection system and method for wafer ultrasonic field

The invention relates to the technical field of semiconductor detection, and discloses a digital detection system and method for a wafer ultrasonic field, and the method comprises the steps: configuring an acoustic topological insulator coupling system, and constructing a non-scattering sound wave transmission channel; a heterogeneous metasurface sound field regulation and control system is constructed, and depth dimension information is obtained; applying an acoustic holographic compensation algorithm to eliminate imaging distortion of the bending area, and outputting compensated sound field distribution; executing a phase recovery and annular reconstruction algorithm to realize high-quality three-dimensional imaging of the marginal region; a self-adaptive coupling adjustment system is realized, and the characteristics of a coupling material are automatically adjusted according to the edge reflection signal quality monitored in real time; the non-scattering sound wave transmission channel is constructed through the acoustic topological insulator coupling system, the problem of serious sound wave scattering in the edge area is effectively solved, the detection sensitivity of the wafer edge area is improved, the defect omission ratio is reduced compared with a traditional method, and the wafer detection integrity is improved.
Owner:SHENYANG HUIYA IND INTELLIGENT EQUIP CO LTD

Near-field acoustical holography testing system in noise environment and application thereof

The invention relates to a near-field acoustical holography testing system in a noise environment and application thereof. The system comprises a rigid acoustical shielding cover, a microphone array,a base, a data collection instrument and an upper computer, wherein the microphone array comprises a plurality of sensors; the rigid acoustical shielding cover comprises a bottom surface and four sides; a plurality of holes are discretely formed in the bottom surface; the number of the holes is consistent with that of the sensors; each hole is in one-to-one correspondence to each sensor; the sensors are embedded in corresponding holes in the bottom surface of the rigid acoustical shielding cover and are in flush with the inner surface of the bottom surface; the microphone array, the data collection instrument and the upper computer are successively connected with each other; and the rigid acoustical shielding cover and the microphone array are fixed and supported by the base. Compared withthe prior art, the near-field acoustical holography testing system has the advantage that the noise source surface vibration velocity can be more conveniently rebuilt in the noise environment.
Owner:SHANGHAI JIAO TONG UNIV

Near-field acoustical holography measurement method in limited space based on equivalent source method

The invention discloses a near-field acoustical holography measurement method in a limited space based on an equivalent source method, and the method comprises the steps: 1, building a near-field acoustical holography measurement model in the limited space, and obtaining the sound pressure and vibration velocity of a sound source in a measurement surface in the limited space: 2, configuring the number of virtual sources and the positions of the virtual sources; 3, establishing a near-field acoustical holography measurement model of the monopole point sources in the limited space, and obtaining the sound pressure vibration velocity of each monopole point source in a measurement surface in the limited space; 4; solving a Green function in the limited space; 5, solving sound pressure and vibration velocity information on a sound source measurement surface of the known structure through the transfer relation solved in the previous step to obtain the source intensity of the equivalent source in the structure; 6, calculating information such as sound pressure of the structure in the free field through the solved source intensity of the equivalent source. According to the method, a limited space test environment is considered, a traditional equivalent source method is improved, and the influence of an interface in a limited space on sound pressure and a vibration velocity field of a source surface is considered, so that the reconstruction precision is improved.
Owner:HARBIN ENG UNIV

Plate structure sound field reconstruction method based on microphone measuring point optimization and broadband acoustical holography

The invention relates to a plate structure sound field reconstruction method based on microphone measurement point optimization and broadband acoustical holography, and relates to the field of structure radiation sound field reconstruction, and the method comprises the following steps: S1, obtaining a microphone measurement sound pressure column vector; s2, establishing a sound pressure transfer matrix between the measured sound pressure column vector and the source intensity of the equivalent source point; s3, selecting and optimizing the sound pressure data measured by the microphone by using an effective independence method; s4, solving a source intensity vector of an equivalent source point by using a broadband acoustical holography technology; s5, establishing a sound pressure transfer matrix of the equivalent source point and the field point to be reconstructed; and S5, obtaining the sound pressure of the field point to be reconstructed. According to the invention, the sound pressure data acquired by the limited microphone measuring points is ensured to the greatest extent to have significance.
Owner:RES INST 708 OF CHINA STATE SHIPBUILDING CORP

Cylindrical shell sound field step-by-step combination reconstruction method based on plane testing

The invention discloses a cylindrical shell sound field step-by-step combination reconstruction method based on plane testing. The method comprises the following steps: establishing an optimal intermediate conversion surface conformal with a to-be-measured cylindrical shell sound source; on the basis of statistics of an optimal near-field acoustic holography theory, reasonably selecting a conformal conversion surface with the minimum total reconstruction error of primary reconstruction of a plane wave function; converting plane test sound pressure data into a cylindrical conformal conversion surface by utilizing statistical optimal plane near-field acoustic holography; and calculating the sound pressure of the cylindrical sound source by utilizing the statistical optimal cylindrical surface near-field acoustical holography and the sound pressure of the conversion surface. The characteristics that a plane wave function has a relatively simple requirement on a holographic surface test and a cylindrical wave function has higher reconstruction precision on a sound field of a cylindrical shell structure are combined, the limitation that data acquisition is difficult due to the fact thata holographic surface and a sound source surface are required to be conformal in a traditional method is broken through, high-precision reconstruction of the sound field of the cylindrical shell structure is achieved, the reconstruction precision of the cylindrical shell structure is improved, and the problem that the holographic surface conformal with the shell structure is difficult to arrangein actual testing is solved.
Owner:XI AN JIAOTONG UNIV

Underwater structure low-frequency radiation sound power forecasting method based on blind source separation

The invention discloses an underwater structure low-frequency radiation sound power forecasting method based on blind source separation, and the method comprises the following steps: (1), setting a housing sound source in a shallow sea environment, and obtaining discrete sound pressure; (2) obtaining an estimation signal of the source signal through a blind source separation algorithm; (3) windowing the estimated signal space data of the source signal in the z direction to obtain the sound pressure propagating outwards after windowing; (4) the sound pressure propagating outwards is converted into a wave number domain through discrete space Fourier transform, and a holographic surface sound pressure cylindrical wave spectrum is obtained; (5) filtering evanescent waves in a wavenumber domain by using a wavenumber domain filter to obtain propagation waves on a holographic surface; (6) transmitting the filtered sound pressure to a far field in a spherical shape through a near-field acoustical holography technology by means of stable-phase estimation; (7) deducing the sound intensity by using the far-field sound pressure so as to obtain the radiation sound power; according to the invention, the measurement workload is reduced; measurement is carried out on a holographic surface close to a sound source, the influence of boundary reflection is small, and a calculation result is accurate.
Owner:JIANGSU UNIV OF SCI & TECH

Sound field reconstruction system and method based on sound pressure and particle vibration velocity

The invention discloses a sound field reconstruction system and method based on sound pressure and particle vibration velocity, and the system comprises a multi-sensor scanning module which is used for carrying out the scanning through an array composed of sound vector sensors, and obtaining the sound pressure and particle vibration velocity data of a measurement surface; a multi-channel real-time data acquisition module, used for performing multi-channel real-time acquisition on sound pressure and particle vibration velocity data based on labview; a filtering module, used for filtering data points of which the amplitudes are smaller than a preset value on the measuring surface by using the amplitude filtering coefficient of the sound field measuring surface; and a sound field reconstruction module, used for performing sound field reconstruction by using a near-field acoustical holography method based on an equivalent source method, including sound field reconstruction of sound pressure, sound field reconstruction of mass point vibration velocity and sound field reconstruction of a sound intensity field. The mass point vibration velocity is introduced on the basis of the original equivalent source method near-field acoustical holography based on sound pressure to reconstruct the sound field, so that the sound field reconstruction precision and the sound source positioning precision are effectively improved.
Owner:UNIV OF SCI & TECH BEIJING

Sound field reconstruction method based on planar array scanning

The invention belongs to the technical field of mechanical structure sound radiation signal processing, and discloses a sound field reconstruction method based on planar array scanning, which comprises the following steps of: performing stepping scanning in a spatial two-dimensional direction by using a small planar array to obtain sound pressure data of scanning planar arrays at different positions; overlapping measurement is carried out in adjacent areas of the scanning area arrays, and phase deviation caused by non-simultaneous measurement between sound pressure values of the adjacent scanning area arrays is calculated; and by averaging the sound pressure amplitudes at the overlapping positions, the complex sound pressure data on all the scanning area arrays are combined to the synthetic measurement surface. And the sound pressure value of the synthetic measurement surface is combined with a near-field acoustical holography method based on Fourier transform to realize reconstruction of a space sound field. According to the method, the sound field measurement and reconstruction in a larger range are completed by using fewer measuring points, the number of required acoustic sensors is small, the measurement cost is low, the sound field reconstruction precision is high, the calculation speed is high, the window effect problem in a traditional sound field reconstruction method is effectively avoided, and the size modulation of a synthetic measurement surface is realized.
Owner:NAVAL UNIV OF ENG PLA

Patch near-field acoustic holography-visualization method for three-dimensional distribution of objective parameters of sound quality

The invention discloses a three-dimensional distribution visualization method for sound quality objective parameters based on a Patch near-field acoustical holography technology. According to the method, frequent scanning measurement is carried out on the surface of a large-scale complex sound source by means of a small microphone array in a sound field formed by large-scale structured sound source radiation, wherein incoming waves and outgoing waves exist in the sound field; the distribution information of acoustic quantities and sound quality objective parameters in the whole space sound field can be obtained through a Patch near-field acoustical holography and sound quality coupling matrix calculation model, and therefore the three-dimensional distribution visualization for the acoustics physical quantities and the sound quality objective parameters can be achieved.
Owner:ZHEJIANG UNIV OF TECH

Cross-domain wireless acoustic communication system and method based on acoustic holography

The invention discloses a wireless cross-domain acoustic communication system and method based on acoustical holography. The acoustical holography device used for cross-domain acoustic communication is composed of a single-layer acoustical holography phase plate, an array transducer and a camera vision module, each array element of the array transducer has a connected state and a non-connected state, and after a communication coding signal transmitted in water is received, the single-layer acoustical holography phase plate is connected with the camera vision module through the single-layer acoustical holography phase plate. The transducer array elements at the corresponding positions can be sequentially gated according to the sequence, dynamic regulation and control of an incident sound field are realized, the incident sound field passes through the single-layer holographic phase plate and is subjected to phase modulation to be transmitted to a water-air interface, the interface is deformed under the action of acoustic radiation force, and the camera vision module is used for capturing, analyzing and decoding the water surface deformation condition, so that the water surface deformation condition is obtained. And information wireless receiving across a water-air interface is completed. According to the invention, underwater information can be directly transmitted to the air, the equipment is simple, the requirement on the relative position of transmitting-receiving equipment is not strict, and the device is suitable for a liquid environment with any temperature, salinity and density.
Owner:ZHEJIANG UNIV

A digital detection system and method for wafer ultrasonic field

The present invention relates to the field of semiconductor detection technology, and discloses a digital detection system and method for a wafer ultrasonic field. The digital detection method for a wafer ultrasonic field comprises: configuring an acoustic topological insulator coupling system to construct a scattering-free acoustic wave transmission channel; constructing a heterogeneous metasurface acoustic field control system to obtain depth dimension information; applying an acoustic holographic compensation algorithm to eliminate imaging distortion in a curved area and output a compensated acoustic field distribution; executing a phase recovery and annular reconstruction algorithm to achieve high-quality three-dimensional imaging of an edge area; implementing an adaptive coupling adjustment system to automatically adjust coupling material properties according to the quality of a real-time monitored edge reflection signal. The present invention constructs a scattering-free acoustic wave transmission channel through the acoustic topological insulator coupling system, effectively solving the problem of severe acoustic wave scattering in the edge area, thereby improving the detection sensitivity of the wafer edge area, reducing the defect missed detection rate compared with traditional methods, and improving the integrity of wafer detection.
Owner:SHENYANG HUIYA IND INTELLIGENT EQUIP CO LTD