Method, system, device and storage medium for constructing a three-dimensional sound field with high precision

Abstract

The present invention discloses a method, system, device and storage medium for constructing a three-dimensional sound field with high precision, which can be adapted to any acoustic phased array or metamaterial, including geometric features such as the scale, quantity, position of the transmitting units and the acoustic radiation performance, and is optimized for different types of transmitting units; uses the acoustic holography algorithm, through iterative optimization, makes full use of the performance of the phased array or metamaterial to construct an arbitrary three-dimensional sound field distribution with high precision, such as constructing spatial multi-beams, multi-foci and the distribution of arbitrary sound intensities in space, generating arbitrary acoustic images, etc.; realizes high-precision control of sound energy, including the accuracy of spatial position and distribution intensity, and improves the application experience of acoustic means in the fields of consumer electronics, biomedical engineering and underwater acoustic detection, etc. This acoustic holography algorithm is calculated based on a clear physical process, uses convolution or frequency-domain calculation in the process of calculating sound propagation, has a fast calculation speed, can be calculated in real time, and is used for constructing a real-time three-dimensional sound field distribution with high precision.

Description

Technical Field

[0001] The present invention belongs to the technical field of acoustic holography algorithms, and particularly relates to a method, system, device and storage medium for accurately constructing a three-dimensional sound field. Background Art

[0002] Precise regulation of the sound field has a wide range of applications in fields such as consumer electronics, biomedical engineering, and underwater acoustic detection. For example, directional sound transmission to achieve highly directional emission of sound waves, ultrasonic gesture recognition, etc. In biomedical engineering, ultrasonic ablation and ultrasonic stimulation in the human body all require high-precision sound field construction. Otherwise, functions such as ablation or stimulation cannot be achieved. Without precision assurance, it will bring unpredictable risks to patients.

[0003] Moreover, when using acoustic levitation technology to perform three-dimensional manipulation on multiple particles, high-precision three-dimensional sound field construction is also required to control the microparticles at the desired positions. Real-time microparticle movement also requires a sound field construction algorithm that can perform real-time operations.

[0004] The functions realized by traditional algorithms are limited and do not support the construction and operation of multiple sound fields. At the same time, because different sound fields cannot be decoupled, it is impossible to achieve the construction of multiple sound fields through simple linear superposition, and even more impossible to construct different types of sound fields simultaneously. Traditional algorithms cannot accurately control the sound intensity, that is, they cannot accurately control the distribution and intensity of sound energy. At the same time, because adjusting the sound intensity at a certain place will also affect other components in the total sound field, it is even more impossible to accurately control the energy of multiple target sound fields separately. The application scope of traditional algorithms is limited. For example, they can only be applied in simplified situations such as regular radiation surfaces, equally spaced arrays, consistent element sizes, and planar sound sources. At the same time, they cannot be optimized for radiation units with different performance characteristics such as phased arrays and metamaterials. Summary of the Invention

[0005] The purpose of the present invention is to provide a method, system, device and storage medium for accurately constructing a three-dimensional sound field, which can set various complex emission models, can reuse and accelerate for regular models, can make full use of the performance of phased arrays or metamaterials (including radiation characteristics and consistency errors), accurately construct any three-dimensional sound field distribution, realize the simultaneous high-precision construction of multiple types of sound fields, can achieve high-precision control of sound energy, including the accuracy of spatial position and distribution intensity (sound intensity); improve the application experience of acoustic means in fields such as consumer electronics, biomedical engineering, and underwater acoustic detection.

[0006] To solve the above problems, the technical solution of the present invention is as follows:

[0007] A method for accurately constructing a three-dimensional sound field, applicable to constructing a three-dimensional sound field with an acoustic phased array or a metamaterial, includes:

[0008] Initialize the acoustic holography algorithm according to the performance parameters of the transmitting device;

[0009] Construct an initial sound field as the reference distribution of the three-dimensional sound field to be constructed;

[0010] Simulate the sound propagation process and back-propagate the target sound field to the transmitting plane;

[0011] Obtain the feedback information of the sound field distribution at the transmitting plane after back-propagation, and calculate the transmission parameters of the transmitting plane;

[0012] According to the transmission parameters of the transmitting plane, forward-propagate the target sound field to the position of the initial sound field, obtain the sound field distribution information of the forward propagation, and determine whether the construction quality of the target sound field meets the preset requirements. If so, complete the construction of the three-dimensional sound field;

[0013] If not, then according to the sound field distribution information and reference distribution obtained by forward propagation, correct the target sound field, back-propagate the corrected target sound field to the transmitting plane, obtain the feedback information of the sound field distribution at the transmitting plane after back-propagation, and calculate the transmission parameters of the transmitting plane until the transmission parameters meet the preset requirements.

[0014] According to an embodiment of the present invention, the initializing the acoustic holography algorithm according to the performance parameters of any transmitting device further includes:

[0015] Define the radiation source according to the characteristics of the transmitting device;

[0016] Automatically generate a grid according to the frequency, shape, size, position and angle of the transmitting unit of the transmitting device;

[0017] Among them, the transmission parameters of the transmitting unit can be set as a conventional uniform array, a non-uniformly arranged array or a sparse array; each element can be independently set to any shape and any deflection angle, that is, a non-planar sound source;

[0018] For the transmitting unit with a regular shape, the grid can be reused, that is, only non-repeated grids are generated; for the same elements in the array, reuse can also be achieved, that is, grids are only generated for one element.

[0019] According to an embodiment of the present invention, the constructing the initial sound field as the reference distribution of the three-dimensional sound field to be constructed further includes:

[0020] Define the sound field type, sound field intensity and spatial position of the initial sound field, specify different sound field types for different components in the sound field, and support independent control settings. The sound intensity (W / cm 2 ) of each component can be set, and different coding and modulation methods of each component can also be set;

[0021] Among them, the sound field types include: multi-focus, multi-beam, acoustic vortices of various orders, arbitrary acoustic images, and various sound field types can be arbitrarily combined and constructed at different positions;

[0022] The coding modulation methods include amplitude modulation, phase modulation, and frequency modulation.

[0023] According to an embodiment of the present invention, in the process of simulating the sound wave propagation, the process of backpropagating the target sound field to the emission plane further includes:

[0024] This backpropagation represents a mathematical operation in the algorithm process, and different types of mathematical operations can be selected according to different operation objectives;

[0025] For a homogeneous medium, the backpropagation operation based on the physical model can be used. Based on the conjugate Green's function, numerical calculation methods including Rayleigh integral, finite element, and finite difference are used to implement the backpropagation based on the physical model; here, the homogeneous medium means that the medium for sound wave propagation is uniformly distributed and does not change with time. For example, the still air in free space, sound waves or light waves can propagate freely without interference introduced by the medium;

[0026] For a complex medium, the operation form of error backpropagation can be used. Based on the mathematical optimization method, according to the target sound field, the error is backpropagated to the emission plane; here, the complex medium means that the medium distribution is complex, inhomogeneous, or changes with time; for example, in foggy weather, light scatters everywhere and it is impossible to see distant objects clearly; for example, a glass with uneven thickness makes the objects look distorted when viewed through it; for example, the Doppler effect caused by changes over time;

[0027] In the backpropagation process based on the mathematical model or physical model, the sound field information is encoded into the entire emission plane. Based on the sound field constructed thereby, it has strong robustness and anti-interference ability.

[0028] According to an embodiment of the present invention, in the process of obtaining the feedback information of the sound field distribution at the emission plane after backpropagation and calculating the emission parameters of the emission plane, it further includes:

[0029] The result of the backpropagation is the feedback information;

[0030] For the backpropagation based on the physical model, the sound pressure at the emission surface in the feedback information is extracted, and an integration or spatial filtering operation is performed on the sound pressure on the surface of each emission unit of the emission surface to obtain the emission amplitude and phase of each emission unit on the emission surface;

[0031] For the backpropagation based on the mathematical optimization model, according to different optimization algorithms, the amplitude and phase of the emission unit are adjusted; for example, screening and mutation in the genetic algorithm; and those that can be used in many optimization algorithms, adjusting the emission amplitude and phase of each emission unit according to the gradient, etc.

[0032] After obtaining the transmission amplitudes and phases of each transmitting element in each iteration, they are corrected again according to the radiation performance of the transmitting elements of the used transmitting device, and the transmission amplitudes and phases are classified and quantified to calibrate the consistency and quantization error, obtaining transmission parameters applicable to the current transmitting device to meet the adaptation to different phased arrays or metamaterials;

[0033] When a problem occurs in a certain element in the phased array or metamaterial array, this error information will be brought into the iterative correction to meet the optimization of sound field construction under different working conditions.

[0034] According to an embodiment of the present invention, the correction of the target sound field for backpropagation based on the sound field distribution information and the reference distribution obtained by forward propagation further includes:

[0035] When correcting the transmission amplitude of the target sound field, taking the phase as the degree of freedom, on the basis of retaining the phase distribution of the sound field obtained by forward propagation, initializing the amplitude distribution to the amplitude of the reference distribution;

[0036] When correcting the phase of the target sound field, taking the amplitude as the degree of freedom, on the basis of retaining the amplitude distribution of the sound field obtained by forward propagation, initializing the phase distribution to the phase of the reference distribution;

[0037] When simultaneously correcting the transmission amplitude and phase of the target sound field, according to a preset threshold, performing perturbation correction on the transmission amplitude and phase.

[0038] According to an embodiment of the present invention, the correction of the target sound field for backpropagation further includes:

[0039] Since the reference sound field set artificially may exceed the physical limit that the transmitting device can achieve, when the correction cannot make the algorithm converge or the construction error is still very large after convergence, then according to the sound field distribution obtained by forward propagation, the change amount of the sound field distribution in each step and the reference sound field, solving the correction weighting coefficient to further correct the sound field for improving the construction quality of the sound field.

[0040] A system for constructing a three-dimensional sound field with high precision, applicable to constructing a three-dimensional sound field by an acoustic phased array or metamaterial, includes:

[0041] A parameter setting module, used to initialize the acoustic holography algorithm according to the performance parameters of the transmitting device;

[0042] An initial module, used to construct an initial sound field as the reference distribution of the three-dimensional sound field to be constructed;

[0043] An iterative module is used to simulate the sound propagation process, backpropagate the target sound field to the emission plane; obtain the feedback information of the sound field distribution at the emission plane after backpropagation, and calculate the emission parameters of the emission plane; according to the emission parameters of the emission plane, forward propagate the target sound field to the position of the initial sound field, obtain the sound field distribution information of the forward propagation, and determine whether the construction quality of the target sound field meets the preset requirements. If so, the construction of the three-dimensional sound field is completed; if not, the target sound field is corrected according to the sound field distribution information and the reference distribution obtained by the forward propagation, the corrected target sound field is backpropagated to the emission plane, the feedback information of the sound field distribution at the emission plane after backpropagation is obtained, and the emission parameters of the emission plane are calculated until the emission parameters meet the preset requirements.

[0044] A device for constructing a three-dimensional sound field with high precision includes: a memory and a processor. Computer-readable instructions are stored in the memory. When the computer-readable instructions are executed by the processor, the processor executes the steps in the method for constructing a three-dimensional sound field with high precision in an embodiment of the present invention.

[0045] A storage medium storing computer-readable instructions, when the computer-readable instructions are executed by one or more processors, enabling the one or more processors to execute the steps in the method for constructing a three-dimensional sound field with high precision in an embodiment of the present invention

[0046] Due to the adoption of the above technical solutions, the present invention has the following advantages and positive effects compared with the prior art:

[0047] The method for constructing a three-dimensional sound field with high precision in an embodiment of the present invention can be adapted to any acoustic phased array or metamaterial, including any complex geometric features such as the scale of the emission unit, the shape of the emission unit, the number, the position, and the acoustic radiation performance (such as the emission frequency, the emission amplitude phase accuracy, the radiation surface mode distribution, etc.), and can be optimized for different types of emission units; using the acoustic holography algorithm, through iterative optimization, making full use of the performance of the phased array or metamaterial, constructing any three-dimensional sound field distribution with high precision, such as constructing spatial multi-beams, multi-foci, and any sound intensity distribution in space, generating any acoustic image, etc.; realizing high-precision control of sound energy, including the accuracy of spatial position and distribution intensity, and improving the application experience of acoustic means in the fields of consumer electronics, biomedical engineering, and underwater acoustic detection. The acoustic holography algorithm is calculated based on a clear physical process, using convolution or frequency-domain calculation in the calculation of sound propagation, with a fast calculation speed, capable of real-time calculation, and used for the construction of real-time high-precision three-dimensional sound field distribution. Description of the Drawings

[0048] Figure 1 It is a flow chart of the method for constructing a three-dimensional sound field with high precision in an embodiment of the present invention;

[0049] Figure 2Schematic diagram of the emission plane during the simulation of sound propagation in an embodiment of the present invention;

[0050] Figure 3 Three-dimensional rendering diagram of an arbitrary acoustic image system constructed in an embodiment of the present invention;

[0051] Figure 4 Simulation (left) and measured (right) diagrams of an equal-intensity multi-focus experiment in an embodiment of the present invention;

[0052] Figure 5 Simulation (left) and measured (right) diagrams of an unequal-intensity multi-focus experiment in an embodiment of the present invention;

[0053] Figure 6 Simulation (left) and measured (right) diagrams of a structural vortex sound beam experiment in an embodiment of the present invention;

[0054] Figure 7 Simulation (left) and measured (right) diagrams of an experiment with an arbitrary spatial intensity distribution in an embodiment of the present invention;

[0055] Figure 8 System block diagram for high-precision construction of a three-dimensional sound field in an embodiment of the present invention;

[0056] Figure 9 Schematic diagram of the device for high-precision construction of a three-dimensional sound field in an embodiment of the present invention. Detailed implementation manners

[0057] The following further elaborates in detail on a method, system, device, and storage medium for high-precision construction of a three-dimensional sound field proposed by the present invention in combination with the accompanying drawings and specific embodiments. The advantages and features of the present invention will be clearer based on the following description and the claims.

[0058] Embodiment 1

[0059] Please refer to Figure 1 , this embodiment provides a method for high-precision construction of a three-dimensional sound field, which is applicable to constructing a three-dimensional sound field using an acoustic phased array or metamaterial. The construction method of this three-dimensional sound field includes the following steps:

[0060] S1: Initialize the acoustic holography algorithm according to the performance parameters of the emission device;

[0061] S2: Construct an initial sound field as the reference distribution of the three-dimensional sound field to be constructed;

[0062] S3: Simulate the sound propagation process and backpropagate the target sound field to the emission plane;

[0063] S4: Obtain the feedback information of the sound field distribution at the emission plane after backpropagation and calculate the emission parameters of the emission plane;

[0064] S5: According to the emission parameters of the emission plane, forward propagate the target sound field to the position of the initial sound field, obtain the sound field distribution information of the forward propagation, and determine whether the construction quality of the target sound field meets the preset requirements. If so, complete the construction of the three-dimensional sound field;

[0065] S6: If not, then correct the target sound field according to the sound field distribution information and the reference distribution obtained by the forward propagation, backward propagate the corrected target sound field to the emission plane, obtain the feedback information of the sound field distribution at the emission plane after the backward propagation, and calculate the emission parameters of the emission plane until the emission parameters meet the preset requirements.

[0066] In step S1, initialize the acoustic holography algorithm according to the performance parameters of the emission device.

[0067] The emission device is usually a phased array formed by arranging many small emission units, or assisted by a metamaterial designed manually for acoustic wave emission. When applied in different scenarios, there are different requirements for the device size, device power consumption, and device cost (complexity). Considering that these emission devices usually have many special properties, such as different emission unit sizes, different acoustic wave frequencies, and irregular (non-regular distribution) arrangements of emission units in different scenarios, etc.; the algorithms proposed previously must be applied to regularly arranged emission arrays, or can only be aimed at ultrasonic waves with a frequency of 40 kHz, etc.

[0068] In view of the above situation, in this embodiment, there is no clear limitation on the setting of the emission parameters of the emission device, and corresponding settings can be made according to the current emission device. For example, set the working frequency, spatial position, shape, pointing angle, and modal distribution of the radiation surface of each emission device through code to calculate the directivity of the radiation sound field or the sound field distribution within a certain three-dimensional space position. It is also possible to import the relevant sound field results calculated by CAE (Computer Aided Engineering).

[0069] Specifically, in step S1, this embodiment defines the physical parameters of the sound propagation medium, such as the sound speed, density, and attenuation coefficient. When using a simplified model, only the sound speed of the medium needs to be defined. For example, the sound speed of air at room temperature is about 343 (m / s), and the sound speed in water is about 1485 (m / s). Define the acoustic holography working frequency. According to the frequency and the sound speed, the wavelength can be calculated (λ = c / f), which will be used to determine the grid space interval. Define the radiation source, set the radiation characteristics such as sensitivity according to the characteristics of the emission units used, and can be optimized for phased arrays and metamaterials. According to the shape, size, position, angle, etc. of the emission units, a radiation grid is automatically generated. For example Figure 2Automatically generated according to the following parameters, where black represents the effective radiation area (excluding the border). The array elements are circular with a diameter of 7 (mm). The array elements are arranged in a two-dimensional uniform grid, with a total of 16×16, and the spacing is 10.5 (mm). The emission axis makes an angle of 90 degrees with the x-y plane. It is also possible to manually divide the grid to generate a two-dimensional matrix similar to Figure 2 and import it directly for use in the algorithm.

[0070] In step S2, an initial sound field is constructed as the reference distribution of the three-dimensional sound field to be constructed.

[0071] The initial sound field constructed in this embodiment can cover the current mainstream sound field construction requirements, including: focusing (single point and multi-point), beamforming (single direction and multi-direction), acoustic vortex, arbitrary acoustic patterns, so that the receiving device is not affected by the usage scenario. At the same time, the position of the sound field can be arbitrarily specified (in three-dimensional space), and the quality of the constructed sound field still cannot exceed the physical limit, but only achieve the optimal sound field construction based on the current hardware conditions.

[0072] Specifically, in this embodiment, the sound field to be constructed (p ref ) is defined. The sound field type, intensity, and spatial coordinates are defined. The sound field type usually includes beam, focusing, multi-point focusing, acoustic vortex, etc., and the sound field distribution can also be customized through a matrix; the intensity represents the sound wave amplitude, and different components in the sound field can be specified with different intensities to achieve independent control; the spatial coordinates are the relative coordinates with respect to the radiation source, which can determine the height in the z direction and the offset in the x-y direction of the sound field. The sound intensity can be specified for each component of each sound field. For example: define that the intensity of each focus of multi-point focusing is 1 (W / cm 2 ), and the coding and modulation method, for example: define the amplitude coding for each focus of multi-point focusing, that is, the focus intensity changes with time. The intensity of each focus defined above is 1 (W / cm 2 ) will become the maximum amplitude of the amplitude coding, that is, the amplitude can be arbitrarily modulated between 0 - 1 (W / cm 2 ); if the phase coding for each focus of multi-point focusing is defined, then the phase constraint conditions need to be added on the basis of the intensity of each focus defined above being 1 (W / cm 2 ), that is, some foci have a phase of 0, some foci have a phase of pi, etc.; if the frequency coding for each focus of multi-point focusing is defined, then by setting the emission frequency, different frequencies generate foci with an intensity of 1 (W / cm 2 ) at the corresponding focus positions. After determining the reference sound field, the iterative process will be entered.

[0073] In step S3, simulate the sound propagation process and backpropagate the target sound field to the emission plane. Among them, the backpropagation process based on the physical model can be completed by calculation methods such as the finite element method, the finite difference method, and the boundary integral method. Taking the boundary integral method as an example below, the sound propagation process is briefly described. Considering the time-harmonic case, the active acoustic wave equation can be described as:

[0074]

[0075] Let Get the free-space Green's function:

[0076]

[0077] where is the wave number, and the sound field distribution satisfies the Kirchhoff-Helmholtz integral formula:

[0078]

[0079] where is the normal of the radiation source plane. After the sound pressure distribution on the given radiation plane is given, the sound field can be calculated using the following formula (1):

[0080]

[0081] Let Therefore, the spatial sound pressure can be calculated by convolution p = p0 * h or in the Fourier domain using the angular spectrum method P = P0 · H. Use formula (1) to backpropagate the target sound field to the emission plane.

[0082] For the finite element method and the finite difference method, they will not be introduced here for the time being. The acoustic holography algorithm is compatible with these traditional sound field simulation methods.

[0083] Based on the backpropagation process of the mathematical model, the error between the calculated output value (the first step is the initial value) and the target function can be designed with different target functions including the value of the reference sound field to be constructed, and the derivative operations on the reference sound field to be constructed. For example, the total error of the sound field, the peak signal-to-noise ratio of the sound field, the average noise level of the sound field, etc. For different types of sound fields, there are also unique target functions, such as the focal intensity and the full width at half maximum of the focus for multi-point focusing; the angular spectrum purity of the acoustic vortex, etc.

[0084] In step S4, obtain the feedback information of the sound field distribution at the emission plane after backpropagation, and calculate the emission parameters of the emission plane.

[0085] Backpropagation based on the physical model: Calculate the emission amplitude and phase of the emission plane according to the sound field distribution of the emission plane obtained by backpropagation. Simulate the real reception situation and integrate the sound pressure propagated to the surface of the array element:

[0086]

[0087] The above-integrated p tn is a complex number, representing the amplitude and phase emitted by the nth array element.

[0088] Backpropagation based on a mathematical model: According to the backpropagation of errors, solve the partial derivatives of each transmitting array element with respect to the error, and use the gradient descent method to change the transmission parameters of each transmitting array element.

[0089] p tn * = w(p z , Δp z , p ref )p tn

[0090] If it is a screening algorithm such as a genetic algorithm, the population is screened and mutated according to the error to obtain better transmission parameters.

[0091] After obtaining the transmission parameters, these parameters need to be graded and quantized according to the element performance. For example, in the case of m-level quantization of both amplitude and phase, round(p * m) / m, where 'round' represents rounding of the amplitude and phase. For the characteristics of some metamaterials, where the amplitude and phase are in a non-uniform distribution form, the specific performance values can be written into the algorithm and corrected by the nearest neighbor matching method.

[0092] In step S5, according to the transmission parameters (p tn ) of the emission plane, and the radiation characteristics (Mod tn ) of the emission unit, propagate forward to the target position, and determine whether the construction quality of the target sound field meets the preset requirements. If so, the construction of the three-dimensional sound field is completed.

[0093] Specifically, the radiation characteristics (Mod tn ) of the emission unit include the consistency error of each emission unit and the distribution of the surface radiation modes, that is, the vibration directions on the entire radiation surface are not consistent. Multiply p tn by Mod tn , and use formula (1) to propagate the sound field forward to the position of the sound field to be constructed to obtain (p z ), and determine whether it meets the iteration completion condition (such as the requirements for construction quality or the maximum number of iterations, etc.). If it meets, end the operation and output the array element transmission parameters (p t0 ). If it does not meet, enter the next step.

[0094] Among them, the forward propagation can also use methods such as the boundary integral method, finite element method, and finite difference method. The acoustic holography algorithm can be compatible with various sound field calculation methods, and can also import the forward propagation sound field obtained by external calculation or experimental measurement through an interface. The algorithm can reuse the grid for the emitting units with symmetry and the arrays with the same emitting units. For example, for a single circular radiation unit, the radiation field shows an axisymmetric form, and the grid can have only one line, and the axisymmetric splicing is automatically completed during the calculation. Other emitting unit shapes with symmetry are similar, and the operation complexity can be reduced through reuse. For the reuse of the same-shaped units in the array, only the grid construction for one emitting unit needs to be carried out, and the repeated array elements only need to be weighted and shifted and superimposed. The weighting value depends on different emission parameters and emission modes, and the shift amount depends on different positions. During forward propagation, the foreign objects on the propagation path can be corrected. The acoustic properties of the foreign objects are different from those of the propagation medium, and the sound wave scatters when interacting with the foreign objects, causing the sound field construction to deviate from the calculation result in free space. Bring the foreign object model into the forward propagation model, calculate its scattered field and superimpose it with the sound field calculated in free space to correct the sound field construction.

[0095] In step S6, if the construction quality of the target sound field does not meet the preset requirements, then according to the sound field distribution information and the reference distribution obtained by forward propagation, correct the target sound field for backward propagation, backward propagate the corrected target sound field to the emission plane, obtain the feedback information of the sound field distribution at the emission plane after backward propagation, and calculate the emission parameters of the emission plane until the emission parameters meet the preset requirements.

[0096] Specifically, according to the sound field distribution (p z ) calculated by forward propagation and the reference sound field distribution (p ref ), correct the target sound field for backward propagation. When focusing on the amplitude distribution, the phase can be used as a degree of freedom. On the basis of retaining the p z phase distribution, initialize the amplitude distribution to abs(p ref ), that is

[0097] p z = abs(p ref )exp(angle(p z ))

[0098] When focusing on the phase distribution, the amplitude can be used as a degree of freedom. On the basis of retaining the p z amplitude distribution, initialize the phase distribution to angle(p ref ), that is:

[0099] p z = abs(p z )exp(angle(p ref ))

[0100] When both the emission amplitude and phase are required simultaneously, perturbation correction can be performed on the amplitude and phase. The perturbation correction can be achieved through geomean(p z ,p ref ). It should be noted that the correction cannot exceed the set threshold, otherwise, the perturbation will be too large and lead to non-convergence. When non-convergence occurs or the effect is not good, the correction weighting coefficient will be solved based on the sound field distribution obtained by forward propagation, the change amount of the sound field distribution at each step, and the reference sound field. For example, through low-pass filtering, the high-frequency components that are difficult to construct can be filtered out, and then a new reference sound field can be obtained. The ratio of its amplitude and phase information to that of the original reference sound field is used as the new correction coefficient and added to the iteration to achieve the optimal construction under the physical conditions of the current emission device.

[0101] In application scenarios such as communication and dynamic control, different sound field types require different coding methods. When constructing different types of sound fields, additional constraints on amplitude or phase can be superimposed to achieve the coding of the sound field. Frequency modulation is achieved by dynamically adjusting the emission frequency.

[0102] For the correction of the target sound field of backpropagation, it can also be based on mathematical optimization methods. Set the objective function, such as SNR(p z ,p ref ), and use optimization algorithms such as gradient descent or genetic algorithm to solve for p t0 * with better construction effect; or based on p z and its change amount, that is, Δp z and p ref , as the weight coefficient to correct p tn :

[0103] p tn * = w(p z ,Δp z ,p ref )p tn

[0104] Or based on the physical inverse process, through the p z corrected by backpropagation, the sound field distribution p t0 * at the emission array element calculated using formula (1) is obtained, so as to obtain the emission amplitude and phase of the array element. After obtaining the new emission parameters p t0 * of the array element, return to step S3 for iteration.

[0105] The method for constructing a three-dimensional sound field with high precision is described above. Below, with specific parameters, the effect of constructing a sound field with high precision is demonstrated: Transmission parameters of the transmitting device: The speed of sound in the air as the propagation medium is 343 (m / s), the working frequency of sound wave transmission is 40 (kHz), the acoustic emission element is 7 (mm), the interval is 10.5 (mm), and 16×16 are supplied. And Figure 2 It is consistent with the drawing. Figure 3 It is a three-dimensional rendering diagram, depicting a conceptual diagram of sound waves being emitted by a phased array and generating a specific sound pressure distribution above.

[0106] Below, several special sound fields constructed using the method in this embodiment will be demonstrated to reflect the diversity and high-precision characteristics of this method for sound field construction.

[0107] Figure 4 To construct 8 equally intense focal points in space, the left column is the simulation result, and the right column is the experimental measurement result. The first row is the sound field intensity distribution diagram, and the second row is the intensity at each focal point. Among them, '×' represents the preset intensity, and 'o' represents the experimentally measured intensity. It can be seen that the sound intensity at each focal point is 1 (W / cm 2 ). The construction plane is located at z = 200 (mm), and the focal point positions are the origin and the vertices of a heptagon with a radius of 30 (mm).

[0108] Figure 5 To construct 8 unequally intense focal points in space, the sound intensity of the focal points varies between 0.5 - 1 (W / cm 2 ). The picture layout settings are the same as Figure 4 . It can be seen that the construction of focal points with different intensities still matches the preset with high precision.

[0109] Figure 4 And Figure 5 , which reflects that the algorithm can design and construct multiple focal points for a certain transmitting array, and the position and sound intensity of each focal point are precisely controllable manually. There will be no situation where accurately controlling one focal point makes it impossible to control other focal points, nor will reducing the intensity of one focal point cause the intensity of another focal point to increase. And the experimental verification is passed.

[0110] Figure 6 To construct a structural vortex sound beam, this sound vortex has both 1st and 4th topological orders simultaneously. As another special sound field different from focusing, it is difficult to construct a sound vortex under traditional circumstances. Here, two different sound vortices can be constructed simultaneously,

[0111] Figure 7To construct an acoustic field distribution with arbitrary continuous intensity in a three-dimensional space, without loss of generality, the letters 'F' and 'D' are selected as the acoustic fields to be constructed, where 'F' appears at z = 200 (mm) and 'D' appears at z = 300 (mm). An acoustic field with an arbitrary intensity distribution can be achieved, and different intensity distributions can be constructed at two depths simultaneously, which reflects that the acoustic field construction based on this algorithm has a very high degree of freedom and demonstrates the generality of the algorithm.

[0112] The several representative acoustic fields shown above have extensive applications in the fields of imaging, communication, microfluidics, particle control, etc.

[0113] In view of the requirements for high-precision acoustic field construction and control, the present invention provides a method for constructing a three-dimensional acoustic field with high precision, which can be adapted to any acoustic phased array or metamaterial, including geometric features such as the scale, number, and position of the emission units, and acoustic radiation performance such as the emission frequency, emission amplitude phase accuracy, etc. Using the acoustic holography algorithm and through iterative optimization, the performance of the phased array or metamaterial can be fully utilized, and the performance errors (consistency problems) between transducers and quantization errors in the metamaterial design can be corrected. Instead of theoretically optimizing for ideal situations, it can be optimized for the actual existing emission devices under the current technological level to construct an arbitrary three-dimensional acoustic field distribution with high precision, such as constructing spatial multi-beams, multi-foci, and arbitrary acoustic intensity distributions in space, and generating arbitrary acoustic images, etc. The calculation of this acoustic holography algorithm is based on a clear physical process, using convolution or frequency-domain calculation in the process of calculating acoustic propagation, with a fast calculation speed, capable of real-time calculation, and used for the construction of a real-time high-precision three-dimensional acoustic field distribution.

[0114] Embodiment 2

[0115] This embodiment provides a system for constructing a three-dimensional acoustic field with high precision, which is applicable to constructing a three-dimensional acoustic field using an acoustic phased array or metamaterial. Please refer to Figure 8 , the system includes:

[0116] A parameter setting module 1, configured to configure the emission parameters of the emission device based on the acoustic holography algorithm;

[0117] An initial module 2, configured to construct an initial acoustic field as a reference distribution for the three-dimensional acoustic field to be constructed;

[0118] The iterative module 3 is used to simulate the sound propagation process, back-propagate the target sound field to the emission plane; obtain the feedback information of the sound field distribution at the emission plane after back-propagation, and calculate the emission parameters of the emission plane; according to the emission parameters of the emission plane, forward-propagate the target sound field to the position of the initial sound field, obtain the sound field distribution information of the forward propagation, and determine whether the construction quality of the target sound field meets the preset requirements. If so, the construction of the three-dimensional sound field is completed; if not, the target sound field used for back-propagation is corrected according to the sound field distribution information and the reference distribution obtained by the forward propagation, the corrected target sound field is back-propagated to the emission plane, the feedback information of the sound field distribution at the emission plane after back-propagation is obtained, and the emission parameters of the emission plane are calculated until the emission parameters meet the preset requirements.

[0119] The functions and implementation methods of the above parameter setting module 1, initial module 2 and iterative module 3 are the same as those in the first embodiment above, and will not be repeated here.

[0120] Embodiment 3

[0121] This embodiment provides a device for constructing a three-dimensional sound field with high precision. Please refer to Figure 9 , the device 500 for constructing a three-dimensional sound field with high precision may vary greatly due to configuration or performance, and may include one or more processors (central processing units, CPU) 510 (for example, x86, arm architecture processors or FPGAs) and a memory 520, and one or more storage media 530 (for example, one or more mass storage devices) for storing application programs 533 or data 532. Among them, the memory 520 and the storage media 530 can be transient storage or persistent storage. The program stored in the storage media 530 may include one or more modules (not shown in the figure), and each module may include a series of instruction operations on the device 500 for constructing a three-dimensional sound field with high precision.

[0122] Furthermore, the processor 510 can be set to communicate with the storage media 530 and execute a series of instruction operations in the storage media 530 on the device 500 for constructing a three-dimensional sound field with high precision.

[0123] The device 500 for constructing a three-dimensional sound field with high precision may further include one or more power supplies 540, one or more wired or wireless network interfaces 550, one or more input / output interfaces 560, and / or, one or more operating systems 531, such as Windows Serve, Vista, etc.

[0124] Those skilled in the art can understand, Figure 9The shown device structure for constructing a three-dimensional sound field with high precision does not limit the device for constructing a three-dimensional sound field with high precision, and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0125] Another embodiment of the present invention also provides a computer-readable storage medium.

[0126] The computer-readable storage medium can be a non-volatile computer-readable storage medium, and can also be a volatile computer-readable storage medium. Instructions are stored in the computer-readable storage medium. When the instructions run on a computer, the computer is caused to execute the steps of the method for constructing a three-dimensional sound field with high precision in the first embodiment.

[0127] If the method for constructing a three-dimensional sound field with high precision is implemented in the form of program instructions and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of this embodiment, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of software. This computer software is stored in a storage medium and includes several instructions to cause a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present disclosure. The aforementioned storage medium includes: various media such as USB flash drives, external hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs that can store program codes.

[0128] Those skilled in the art can clearly understand that for the sake of convenient and concise description, the specific identification content executed by the above-described system and device can refer to the corresponding process in the foregoing method embodiments.

[0129] The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, provided that these changes fall within the scope of the claims of the present invention and their equivalent technologies, they still fall within the protection scope of the present invention.

Claims

1. A method for constructing a three-dimensional sound field with high precision, characterized in that, Applicable to acoustic phased arrays or metamaterials to construct a three-dimensional sound field, including: Initializing the acoustic holography algorithm according to the performance parameters of the transmitting device; Constructing an initial sound field as the reference distribution of the to-be-constructed three-dimensional sound field; Simulating the sound propagation process and backpropagating the target sound field to the transmitting plane; Obtaining the feedback information of the sound field distribution at the transmitting plane after backpropagation, and calculating the transmission parameters of the transmitting plane; According to the transmission parameters of the transmitting plane, forward-propagating the target sound field to the position of the initial sound field, obtaining the sound field distribution information of the forward propagation, and determining whether the construction quality of the target sound field meets the preset requirements. If so, the construction of the three-dimensional sound field is completed; If not, then according to the sound field distribution information and reference distribution obtained by the forward propagation, correcting the target sound field, backpropagating the corrected target sound field to the transmitting plane, obtaining the feedback information of the sound field distribution at the transmitting plane after backpropagation, and calculating the transmission parameters of the transmitting plane until the transmission parameters meet the preset requirements.

2. The method for accurately constructing a three-dimensional sound field according to claim 1, wherein The initializing the acoustic holography algorithm according to the performance parameters of the transmitting device further includes: Defining the radiation source according to the characteristics of the transmitting device; Automatically generating a grid according to the frequency, shape, size, position and angle of the transmitting units of the transmitting device; Among them, the transmission parameters of the transmitting units can be set as a conventional uniform array, a non-uniformly arranged array or a sparse array; each element can be independently set to any shape and any deflection angle; For transmitting units with regular shapes, the grid can be reused and only non-repeated grids are generated; for the same elements in the array, reuse can also be achieved and grids are only generated for one element.

3. The method for accurately constructing a three-dimensional sound field according to claim 1, characterized in that, The constructing an initial sound field as the reference distribution of the to-be-constructed three-dimensional sound field further includes: Define the sound field type, sound field intensity, and spatial position of the initial sound field, specify different sound field types for different components in the sound field, and support independent control settings. The sound intensity (W / cm 2 ) of each component can be set, and different coding and modulation methods for each component can also be set; Among them, the sound field types include: multi-focus, multi-beam, acoustic vortices of each order, arbitrary acoustic images, and various sound field types can be arbitrarily combined and constructed at different positions; The coding modulation methods include amplitude modulation, phase modulation, and frequency modulation.

4. The method for accurately constructing a three-dimensional sound field according to claim 1, wherein The simulating the sound propagation process and backpropagating the target sound field to the transmitting plane further includes: For a homogeneous medium, the backpropagation operation based on the physical model can be used. Based on the conjugate Green's function, numerical calculation methods including Rayleigh integral, finite element, and finite difference are used to implement the backpropagation based on the physical model; For a complex medium, the operation form of error backpropagation can be used. Based on the mathematical optimization method, according to the target sound field, the error is backpropagated to the transmitting plane; In the backpropagation process based on the mathematical model or physical model, the sound field information is encoded to the entire transmitting plane. The sound field constructed based on this has strong robustness and anti-interference ability.

5. The method for accurately constructing a three-dimensional sound field according to claim 1, wherein The obtaining the feedback information of the sound field distribution at the transmitting plane after backpropagation, and calculating the transmission parameters of the transmitting plane further includes: The result of the backpropagation is the feedback information; For the backpropagation based on the physical model, extract the sound pressure at the transmitting surface in the feedback information, and perform integral or spatial filtering operations on the sound pressure on the surfaces of the transmitting units on the transmitting surface to obtain the transmission amplitude and phase of each transmitting unit on the transmitting surface; For the backpropagation based on the mathematical optimization model, adjust the amplitude and phase of the transmitting units according to different optimization algorithms; After obtaining the transmission amplitude and phase of each transmitting unit in each iteration, it is corrected again according to the radiation performance of the transmitting units of the used transmitting device, the transmission amplitude and phase are graded and quantified, the calibration consistency and quantization error are calibrated, and the transmission parameters suitable for the current transmitting device are obtained to meet the adaptation to different phased arrays or metamaterials; When a problem occurs in a certain transmitting unit in the phased array or metamaterial array, the error information will be brought into the iterative correction to meet the optimization of the sound field construction under different working conditions.

6. The method for accurately constructing a three-dimensional sound field according to claim 1, characterized in that, The correction of the target sound field for backpropagation according to the sound field distribution information and reference distribution obtained by forward propagation further includes: When correcting the transmission amplitude of the target sound field, taking the phase as the degree of freedom, on the basis of retaining the phase distribution of the sound field obtained by forward propagation, initializing the amplitude distribution to the amplitude of the reference distribution; When correcting the phase of the target sound field, taking the amplitude as the degree of freedom, on the basis of retaining the amplitude distribution of the sound field obtained by forward propagation, initializing the phase distribution to the phase of the reference distribution; When correcting the transmission amplitude and phase of the target sound field simultaneously, a perturbation correction is performed on the transmission amplitude and phase according to a preset threshold.

7. The method for accurately constructing a three-dimensional sound field according to claim 6, characterized in that The correction of the target sound field for backpropagation further includes: When the algorithm for correcting the transmission amplitude and / or phase fails to converge or the error of the constructed sound field does not meet the requirements after convergence, the correction weighting coefficient is solved according to the sound field distribution obtained by forward propagation, the change amount of the sound field distribution and the reference sound field, and the transmission amplitude and / or phase of the sound field are further corrected to improve the construction quality of the sound field.

8. A system for constructing a three-dimensional sound field with high precision, characterized in that, Applicable to the construction of a three-dimensional sound field by an acoustic phased array or metamaterial, including: A parameter setting module for initializing the acoustic holography algorithm according to the performance parameters of the transmitting device; An initial module for constructing an initial sound field as the reference distribution of the three-dimensional sound field to be constructed; An iterative module for simulating the sound propagation process, backpropagating the target sound field to the transmitting plane; obtaining the feedback information of the sound field distribution at the transmitting plane where the backpropagation reaches, calculating the transmission parameters of the transmitting plane; according to the transmission parameters of the transmitting plane, forward propagating the target sound field to the position of the initial sound field, obtaining the sound field distribution information of the forward propagation, and judging whether the construction quality of the target sound field meets the preset requirements. If so, the construction of the three-dimensional sound field is completed; if not, the target sound field is corrected according to the sound field distribution information and reference distribution obtained by forward propagation, the corrected target sound field is backpropagated to the transmitting plane, the feedback information of the sound field distribution at the transmitting plane where the backpropagation reaches is obtained, and the transmission parameters of the transmitting plane are calculated until the transmission parameters meet the preset requirements.

9. A device for constructing a three-dimensional sound field with high precision, characterized in that, Including: A memory and a processor, wherein computer-readable instructions are stored in the memory, and when the computer-readable instructions are executed by the processor, the processor executes the steps in the method for constructing a three-dimensional sound field with high precision according to any one of claims 1 to 7.

10. A storage medium storing computer-readable instructions, characterized in that, When the computer-readable instructions are executed by one or more processors, the one or more processors execute the steps in the method for constructing a three-dimensional sound field with high precision according to any one of claims 1 to 7.

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