Real number weighted processing high-order sound field information extraction and beam forming method

Abstract

The embodiment of the invention provides a real number weighted processing high-order sound field information extraction and beam forming method, and the method comprises the steps: determining the sound field information of an s-th order according to the target feature vector of the s-th order and a signal received by each array element at a first moment, and taking the sound field information of all orders as high-order sound field information; for s being 0 or M / 2, determining a feature beam of the s-order according to the sound field information of the s-order, a target feature value corresponding to the target feature vector of the s-order and an expected direction; for 1 < = s < = M / 2-1, according to the sound field information of the s-th order, a target feature value corresponding to the target feature vector of the s-th order, the sound field information of the M-s-th order, a target feature value corresponding to the target feature vector of the M-s-th order and an expected direction, determining a feature beam of the s-th order; and determining a synthetic beam according to the at least one order of characteristic beam. According to the embodiment of the invention, complex operation can be reduced, and the efficiency of high-order sound field information extraction and beam forming is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of signal processing technology, and in particular to a method for extracting high-order sound field information and beamforming using real-number weighted processing. Background Art

[0002] In the field of acoustic detection, traditional array technology faces the bottleneck of insufficient directivity and resolution at small sizes. Although super-directional beamforming technology can break through the physical aperture limitation, its algorithm complexity and computing resource usage restrict its practical application. As an advanced sound field processing method, the core of the eigenbeam decomposition and synthesis theory is to decompose the complex sound field into basic beams (eigenbeams) with orthogonal characteristics, and reconstruct the target sound field through weighted combination. Specifically, the theory uses the spatial correlation and eigenvalue decomposition of the sound field to map the array received signal to the orthogonal space composed of eigenbeams, and suppresses the interference in the isotropic uniform noise field by extracting the main eigenbeam. At the same time, the weighting coefficient is designed based on the orthogonal completeness of the eigenbeam to achieve directional beam synthesis.

[0003] Specifically, for the application scenario of a uniform circular sound pressure sensor array in an isotropic noise field, this theory exploits the circulant matrix properties of the noise cross-spectral matrix to represent the optimal beam output as the sum of finite-order subcomponents. Each order component is defined as an eigenbeam, thereby providing an accurate analytical solution for high-order super-directivity. Furthermore, by determining the sound field information of different orders, a high-order sound field sensor theory can be established, providing theoretical support for achieving high-resolution sound field analysis and beamforming for small-scale uniform circular sound pressure sensor arrays.

[0004] However, existing eigenbeam decomposition and synthesis theories require extensive complex number operations during implementation, resulting in high computational resource usage and long computational times. In particular, when complex mathematical operations such as multiplication and division are involved, the real and imaginary parts of the complex numbers must be calculated separately, further increasing computational resource usage and extending computational time, thereby reducing the efficiency of high-order sound field information extraction and beamforming. Summary of the Invention

[0005] The embodiments of the present application provide a method for extracting high-order sound field information and forming beams using real-number weighted processing, which can reduce complex operations, thereby reducing computing resource usage and computing time, improving computing efficiency, and further improving the efficiency of high-order sound field information extraction and beamforming.

[0006] The present application provides a method for extracting high-order sound field information and beamforming using real-number weighted processing, including: According to the s-th order target eigenvector and the signal received by each array element in the uniform circular sound pressure sensor array at the first moment, the s-th order sound field information is determined, and the sound field information of all orders is used as high-order sound field information; wherein, , the uniform circular sound pressure sensor array includes M array elements, M is an even number; the uniform circular sound pressure sensor array is placed in the xoy plane and the center of the uniform circular sound pressure sensor array is located at the coordinate origin; array element 0 and array element M / 2 are located on the X axis; for s being 0 or M / 2, according to the s-th order sound field information, the target eigenvalue corresponding to the s-th order target eigenvector and the expected direction, the s-th order eigenbeam is determined; for 1≤s≤M / 2-1, according to the s-th order sound field information, the target eigenvalue corresponding to the s-th order target eigenvector, the Ms-th order sound field information, the target eigenvalue corresponding to the Ms-th order target eigenvector and the expected direction, the s-th order eigenbeam is determined; according to the eigenbeam of at least one order, a synthetic beam is determined; wherein, the s-th order target eigenvector is obtained by removing the imaginary part of each eigencoefficient in the s-th order initial eigenvector; the s-th order initial eigenvector includes The M array elements have one-to-one corresponding characteristic coefficients, and each characteristic coefficient is used to indicate the weight of the signal of the corresponding array element at the s-th order; the imaginary part of each characteristic coefficient in the initial s-th order eigenvector is determined in the process of determining the sound field information of each array element at the s-th order according to the characteristic coefficients corresponding to each array element in the initial s-th order eigenvector and the signal received by each array element at the first moment, and summing the sound field information of all array elements at the s-th order to obtain the sound field information of the s-th order, based on the multiplication of the imaginary part of the characteristic coefficients corresponding to the two axially symmetric array elements in the uniform circular sound pressure sensor array in the initial s-order eigenvector by the difference between the signals received by the two axially symmetric array elements at the first moment, and the signals received by the two axially symmetric array elements at the first moment are similar, and combined with the fact that array element 0 and array element M / 2 are located on the X-axis, the imaginary part of the characteristic coefficients corresponding to array element 0 and array element M / 2 in the initial s-order eigenvector is zero and removed.

[0007] Optionally, the method of determining the s-th order sound field information based on the s-th order target eigenvector and the signal received by each array element in the uniform circular sound pressure sensor array at the first moment includes: when s is an even number, determining the s-th order sound field information based on the s-th order target eigenvector, the even-order response matrix and the incident signal at the first moment; when s is an odd number, determining the s-th order sound field information based on the s-th order target eigenvector, the odd-order response matrix and the incident signal at the first moment; wherein the even-order response matrix is ​​obtained by removing the imaginary part of each response component in the initial response matrix; the odd-order response matrix is ​​obtained by removing the real part and the imaginary unit of each response component in the initial response matrix; the initial response matrix includes response components corresponding to M array elements one by one, each response component is used to indicate the gain and phase deviation of the corresponding array element to the signal of the first incident direction, and the first incident direction is the direction of the incident signal; the imaginary part of each response component in the initial response matrix is ​​obtained by removing the characteristic coefficients corresponding to each array element in the s-th order target eigenvector, The response components corresponding to each array element in the initial response matrix and the incident signal at the first moment determine the sound field information of each array element at the s-th order, and the sound field information of all array elements at the s-th order is summed to obtain the sound field information of the s-th order. In the process, the imaginary parts of the response components corresponding to the two centrally symmetrical array elements in the uniform circular sound pressure sensor array in the initial response matrix cancel each other out and are removed. The real part and the imaginary unit of each response component in the initial response matrix are determined based on the characteristic coefficients corresponding to each array element in the s-th order target eigenvector, the response components corresponding to each array element in the initial response matrix, and the incident signal at the first moment, and the sound field information of all array elements at the s-th order is summed to obtain the sound field information of the s-th order. In the process, the real parts of the response components corresponding to the two centrally symmetrical array elements in the uniform circular sound pressure sensor array in the initial response matrix cancel each other out, and are combined with the s-th order sound field information to indicate the signal reception response in all directions, and the signal reception response is associated with the signal output amplitude in all directions and is removed.

[0008] Optionally, the initial eigenvector of the sth order is:

[0009] in, is the initial eigenvector of order s, for The characteristic coefficient corresponding to the array element m, , is the horizontal azimuth angle of array element m, Indicates transposition, is the imaginary unit, s is the order; The target feature vector of the sth order is:

[0010] in, , is the target feature vector of order s, for The characteristic coefficient corresponding to the array element m.

[0011] Optionally, the initial response matrix is:

[0012] in, is the initial response matrix, for The response component corresponding to the array element m, , is the wave number, is the unit vector of the propagation direction of the incident signal at the first moment, is the coordinate of array element m in the rectangular coordinate system, is the imaginary unit, Indicates transposition, θ and are the vertical pitch angle and horizontal azimuth angle of the incident signal at the first moment respectively; The even-order response matrix is:

[0013] in, is an even-order response matrix, , for The response component corresponding to the array element m, is the horizontal azimuth angle of array element m, r is the straight-line distance between array element m and the coordinate axis point; The odd-order response matrix is:

[0014] in, is an odd-order response matrix, , for The response component corresponding to the array element m.

[0015] Optionally, when s is an even number, determining the s-th order sound field information according to the s-th order target eigenvector, the even-order response matrix, and the incident signal at the first moment includes: When s is an even number, the s-th order sound field information is determined by the following formula:

[0016] in, is the s-th order sound field information, is the characteristic coefficient corresponding to the array element m in the target eigenvector of order s, is the incident signal at the first moment; When s is an odd number, determining the s-th order sound field information according to the s-th order target eigenvector, the odd-order response matrix, and the incident signal at the first moment includes: When s is an odd number, the s-th order sound field information is determined by the following formula: .

[0017] Optionally, the method further includes: The formula for determining the even-order sound field information and the formula for determining the odd-order sound field information are transformed into the following formulas through the Jacobi-Anger expansion:

[0018] in, is a cylindrical Bessel function of the first kind of order s.

[0019] Optionally, for s being 0 or M / 2, determining the s-th order eigenbeam according to the s-th order sound field information, the target eigenvalue corresponding to the s-th order target eigenvector, and the expected direction includes: The eigenbeam of order s is determined by the following formula:

[0020] in, , is the s-th order eigenbeam, It is a parameter that ensures the beam pointing direction response is 1. is the target eigenvalue corresponding to the target eigenvector of order s, For the expected direction, is the s-th order sound field information in the desired direction, is the sth order sound field information, θ and are the vertical pitch angle and horizontal azimuth angle of the incident signal at the first moment respectively; For 1≤s≤M / 2-1, determining the s-th order eigenbeam according to the s-th order sound field information, the target eigenvalue corresponding to the s-th order target eigenvector, the Ms-th order sound field information, the target eigenvalue corresponding to the Ms-th order target eigenvector, and the expected direction includes: The eigenbeam of order s is determined by the following formula:

[0021] in, , is the s-th order eigenbeam, It is a parameter that ensures the beam pointing direction response is 1. is the target eigenvalue corresponding to the target eigenvector of order s, For the expected direction, is the s-th order sound field information in the desired direction, is the s-th order sound field information, is the target eigenvalue corresponding to the target eigenvector of the Ms order, is the sound field information of the Ms-th order in the desired direction, is the Ms-th order sound field information, θ and are the vertical pitch angle and horizontal azimuth angle of the incident signal at the first moment respectively; The target eigenvalue corresponding to the target eigenvector of the sth order is obtained by removing the imaginary part of the initial eigenvalue corresponding to the target eigenvector of the sth order;

[0022] in, is the target eigenvalue corresponding to the target eigenvector of order s, , , is the array element m and the array element The noise correlation between , , , is the horizontal azimuth angle of array element m;

[0023] in, is the initial eigenvalue corresponding to the target eigenvector of order s; The imaginary part of the initial eigenvalue corresponding to the target eigenvector of order s is based on m being 0 and make The imaginary part of is 0, and combined with , The two axially symmetric array elements The imaginary parts of the sum cancel each other out and are removed.

[0024] Optionally, the method further includes: Based on the fact that the target eigenvector of the sth order is the same as the target eigenvector of the Msth order and the target eigenvalue corresponding to the target eigenvector of the sth order is the same as the target eigenvalue corresponding to the target eigenvector of the Msth order, the formula for determining the eigenbeam of the sth order is transformed into:

[0025] in, .

[0026] Optionally, determining a synthetic beam based on at least a first-order eigenbeam includes: The composite beam is determined by the following formula:

[0027] Where s is 0~ At least one of is the synthetic beam, is the sth order characteristic beam, θ and are the vertical pitch angle and horizontal azimuth angle of the incident signal at the first moment respectively.

[0028] The beneficial effects of the high-order sound field information extraction and beamforming method using real number weighted processing in the embodiment of the present application are: Since the s-th order target eigenvector is obtained by removing the imaginary part of each eigencoefficient in the s-th order initial eigenvector, that is, the s-th order target eigenvector is a real number. Therefore, according to the s-th order target eigenvector and the signal received by each array element in the uniform circular sound pressure sensor array at the first moment, the s-th order sound field information is determined, which can reduce complex number operations, thereby reducing memory usage and calculation time, and improving calculation efficiency and the efficiency of determining the s-th order sound field information. In this way, since high-order sound field information is a collection of sound field information of all orders, the efficiency of extracting high-order sound field information is improved. Based on this, for s being 0 or M / 2, the s-th order eigenbeam is determined according to the s-th order sound field information, the target eigenvalue corresponding to the s-th order target eigenvector and the expected direction. For 1≤s≤M / 2-1, the s-th order characteristic beam is determined according to the s-th order sound field information, the target eigenvalue corresponding to the s-th order target eigenvector, the Ms-th order sound field information, the target eigenvalue corresponding to the Ms-th order target eigenvector and the expected direction, and the synthetic beam is determined according to at least one order characteristic beam, thereby improving the efficiency of beam synthesis.

[0029] Furthermore, since the imaginary part of each eigenvalue in the s-th order initial eigenvector is determined based on the eigenvalue corresponding to each element in the s-th order initial eigenvector and the signal received by each element at the first moment, and the sound field information of all elements at the s-th order is summed to obtain the s-th order sound field information, the imaginary part of each eigenvalue in the eigenvalue corresponding to each element in the s-th order initial eigenvector is multiplied by the difference between the signals received by the two axially symmetric elements at the first moment, and the signals received by the two axially symmetric elements at the first moment are similar, and the imaginary part of the eigenvalue corresponding to each element in the s-th order initial eigenvector is zero and is removed based on the fact that element 0 and element M / 2 are located on the X-axis. Therefore, by removing the imaginary part of each eigenvalue in the s-th order initial eigenvector, the s-th order target eigenvector is obtained, thereby ensuring the accuracy of the s-th order target eigenvector, thereby ensuring the accuracy of high-order sound field information extraction and beamforming. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the structure of a uniform circular sound pressure sensor array; Figure 2 A flowchart of a real-number weighted high-order sound field information extraction and beamforming method provided in an embodiment of the present application; Figure 3 (a) is a schematic diagram showing the comparison of the 0th-order sound field information in the desired direction; Figure 3 (b) is a comparative diagram of the first-order sound field information in the desired direction; Figure 3 (c) is a comparative diagram of the second-order sound field information in the desired direction; Figure 3 (d) is a comparative diagram of the third-order sound field information in the desired direction; Figure 3 Middle (e) is a comparative diagram of the 5th-order sound field information in the desired direction; Figure 4 (a) is the response diagram of the maximum value of the 0th-order sound field information output in different directions; Figure 4 (b) is the response diagram of the maximum value of the first-order sound field information output in different directions; Figure 4 (c) is the response diagram of the maximum value of the second-order sound field information output in different directions; Figure 4 (d) is the response diagram of the maximum value of the third-order sound field information output in different directions; Figure 4 Middle (e) is the response diagram of the maximum output of the 4th-order sound field information in different directions; Figure 5 (a) is a comparative diagram of the synthetic beam determined by the 0th-order eigenbeam; Figure 5 (b) is a comparative diagram of the synthetic beam determined by the 0th-order and 1st-order eigenbeams; Figure 5 (c) is a comparative diagram of the synthetic beam determined by the eigenbeams of order 0 to 2; Figure 5 (d) is a comparative diagram of the synthetic beam determined by the eigenbeams of order 0 to 3; Figure 5 (e) is a comparative diagram of the synthetic beam determined by the eigenbeams of the 0th to 4th orders. DETAILED DESCRIPTION

[0031] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0032] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0033] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to"; the term "based on" means "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first" and "second" mentioned in the present invention are only used to distinguish different devices, modules or units, etc., and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0034] It should be noted that the modifications of "one" and "multiple" mentioned in the present invention are illustrative rather than restrictive. Those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0035] The names of the messages or information exchanged between multiple devices in the embodiments of the present invention are only used for illustrative purposes and are not used to limit the scope of these messages or information.

[0036] The uniform circular sound pressure sensor array realizes the directional detection, positioning and analysis of spatial sound waves by utilizing the propagation characteristics of sound waves and the geometric symmetry of the array. It is an important structure in the field of acoustic detection that takes into account both omnidirectionality and flexibility.

[0037] like Figure 1 As shown, the uniform circular sound pressure sensor array includes M array elements, namely element 0 to element M-1. M is an even number, and each array element is a sound pressure sensor, each of which is non-directional. The uniform circular sound pressure sensor array is placed in the xoy plane, with the center of the circle at the coordinate origin. The M array elements are arranged in a circular shape, and the central angle between adjacent array elements is the same. Element 0 and element M / 2 are located on the x-axis.

[0038] like Figure 1 As shown, the elements in the uniform circular sound pressure sensor array except element 0 and element M / 2 are symmetrical based on the X axis, that is, element m and element Mm are symmetrical based on the X axis. It should be noted that the axisymmetry mentioned below refers to the symmetry based on the X axis. The uniform circular sound pressure sensor array is also a centrosymmetric structure, that is, the array element m is centrosymmetric with the array element M / 2+m. The central angle between two adjacent array elements The calculation formula is .

[0039] In related technologies, based on a uniform annular sound pressure sensor array, the process of determining high-order sound field information and synthesizing a beam using the eigenbeam decomposition and synthesis theory can be as follows: The process of determining high-order sound field information can be: According to the s-th order initial eigenvector and the signal received by each array element in the uniform circular sound pressure sensor array at the first moment, the s-th order sound field information is determined, and the sound field information of all orders is used as high-order sound field information.

[0040] in, The initial eigenvector of the sth order includes characteristic coefficients corresponding to M array elements one by one, and each characteristic coefficient is used to indicate the weight of the signal of the corresponding array element in the sth order.

[0041] Specifically, the s-th order sound field information can be determined by the following formula: : (1) in, θ and are the vertical pitch angle and horizontal azimuth angle of the incident signal at the first moment, is the initial eigenvector of order s, indicates the conjugate transpose, Indicates the signal received by each array element in the uniform circular sound pressure sensor array at the first moment, where t is the first moment.

[0042] Specifically, the initial eigenvector of order s This can be shown as follows: (2) in, for The characteristic coefficient corresponding to the array element m, , is the horizontal azimuth angle of array element m, , Indicates transposition, Is an imaginary unit.

[0043] Next, the principle of determining the s-th order initial eigenvector is described.

[0044] For a uniform circular sound pressure sensor array, the noise it receives mainly comes from the ambient noise. For any two array elements in a uniform circular sound pressure sensor array, when the distance between any two array elements is small enough compared to the wavelength (i.e. ), the noise received by the uniform circular sound pressure sensor array has a certain correlation. Therefore, understanding the spatial correlation of environmental noise plays a very important role in improving the performance of the uniform circular sound pressure sensor array.

[0045] Generally speaking, noise can be regarded as a random process, so the noise model is a statistical concept. It can be written as an M×1 vector: (3) in, is the ambient noise received by array element m.

[0046] Based on this, the noise correlation matrix received by the uniform circular sound pressure sensor array is It can be expressed as: (4) in, Indicates the mathematical expectation.

[0047] The noise cross-spectral matrix is ​​defined as , then the noise correlation matrix can be re-expressed as: (5) in, , is the noise power spectrum, is the frequency domain noise signal.

[0048] It should be noted that the normalized noise correlation matrix is the noise cross-spectral matrix .

[0049] Since the spatial isotropic uniform noise field has a spectral density distribution that is independent of direction, that is, waves from all directions in space have the same power. Therefore, considering the case where a uniform circular sound pressure sensor array is located in an isotropic uniform noise field, the noise cross-spectral matrix is It can be expressed as: (6) in, Elements in , , is the array element m and the array element The noise correlation between , , .

[0050] because is a circulant matrix, so we have , U by All the eigenvectors of for The eigenvalue diagonal matrix of The eigenvalues ​​in correspond to the eigenvectors in U. The eigenvalue size indicates the noise energy intensity in the direction of the corresponding eigenvector. The specific expression can be shown as follows: (7) in, is the initial eigenvector of order s, , .

[0051] (8) in, for The corresponding initial eigenvalues ​​are .

[0052] It should be noted that, in order to facilitate distinction from the following text, the eigenvector here is referred to as the initial eigenvector, and the eigenvalue is referred to as the initial eigenvalue.

[0053] It should be noted that since the noise processing method based on the uniform circular sound pressure sensor array is the same as the processing method of the received signal, formula (7) and formula (8) can be used in the processing of the received signal, that is, the initial eigenvector of the sth order is obtained and the initial eigenvalues .

[0054] Indicates the signal received by each array element in the uniform circular sound pressure sensor array at the first moment. It can be expressed as: (9) in, is the initial response matrix, is the incident signal at the first moment, and t is the first moment.

[0055] Initial response matrix It may include response components corresponding to M array elements, each response component is used to indicate the gain and phase deviation of the corresponding array element to the signal of the first incident direction, and the first incident direction is the incident signal at the first moment direction.

[0056] Specifically, the initial response matrix This can be shown as follows: (10) in, is the response component corresponding to array element m, It is used to indicate the gain and phase deviation of the array element m for the signal in the first incident direction. , k is the wave number, is the incident signal at the first moment The unit vector of the propagation direction, is the coordinate of array element m in the rectangular coordinate system, Is an imaginary unit.

[0057] based on Figure 1 , the coordinates of each array element m in the rectangular coordinate system As shown below: (11) in, is the vertical pitch angle of array element m, is the horizontal azimuth angle of array element m, , indicates transposition, r is the straight-line distance between array element m and the coordinate axis point, that is, the radius of the uniform circular sound pressure sensor array.

[0058] It should be noted that in Figure 1 In the coordinate system of is 90°.

[0059] exist Figure 1 The incident signal at the first moment From the direction The incident signal at the first moment is incident on the uniform circular sound pressure sensor array The unit vector of the propagation direction for: (12) in, θ and are the incident signals at the first moment vertical pitch angle and horizontal azimuth angle.

[0060] It should be noted that The negative sign in the expression is due to the incident signal at the first moment The propagation direction is opposite to the direction of the signal source relative to the array.

[0061] Next, we obtain the initial response matrix The process is described below.

[0062] For example, the incident signal received at the origin at the first moment is , then the signal received by array element m at the first moment is Can be: (13) in, , is the imaginary unit, is the incident signal at the first moment frequency, , is the propagation speed of the sound wave, λ is the incident signal at the first moment The wavelength, Indicates the natural directivity of array element m, is the incident signal at the first moment The time delay relative to the reference point when arriving at element m, .

[0063] because is the wave number and , , , therefore, formula (13) can be transformed into formula (14): (14) Since the sound pressure sensor is non-directional, On this basis, combined with formula (14), the signal received by each array element at the first moment is It can be expressed as: (15) in, ,Right now .

[0064] It should be noted that, combined with the above, the response component corresponding to the array element m in the initial response matrix is The incident signal at the first moment The product of is the signal received by array element m at the first moment .

[0065] Based on this, combined with formula (2), formula (9) and formula (10), formula (1) can be expressed as: (16) Obviously, since the initial response matrix , the initial eigenvector of order s and the incident signal at the first moment are all complex numbers. Therefore, in the process of calculating the s-th order sound field information through formula (16), there are a large number of complex operations, and complex operations such as multiplication are involved, which leads to high computing resource usage and long computing time, thereby reducing the efficiency of determining the s-th order sound field information, and further reducing the efficiency of determining high-order sound field information.

[0066] Furthermore, the process of determining the composite beam requires the use of sound field information of each order, the desired direction, and the initial eigenvalues ​​corresponding to the initial eigenvectors of each order. However, since the initial eigenvalues ​​corresponding to the initial eigenvectors of each order are complex numbers, and the determination of the sound field information of each order involves a large number of complex operations, the process of determining the composite beam also involves a large number of complex operations, resulting in high computing resource usage and long operation time, thus reducing the efficiency of composite beam determination.

[0067] To address the above technical issues, embodiments of the present application provide a method for extracting high-order sound field information and beamforming using real-number weighted processing. This method reduces complex operations, thereby reducing computing resource usage and computational time, improving computational efficiency, and thereby improving the efficiency of high-order sound field information extraction and beamforming. This method can be executed by electronic devices, including but not limited to desktop computers, laptops, e-readers, and other electronic devices with data processing capabilities.

[0068] Before specifically describing the high-order sound field information extraction and beamforming method with real number weighted processing provided in the embodiment of the present application, the setting principle of the embodiment of the present application is first explained, which provides the underlying logical basis for the construction and implementation of subsequent solutions.

[0069] First, further expand formula (16): (17) in, for The conjugation of .

[0070] Obviously, the s-th order sound field information is the s-th order initial eigenvector The conjugate transpose of and the linear combination of the signals received by each array element in the uniform circular sound pressure sensor array at the first moment.

[0071] This linear combination can be understood as the superposition of the sound field information of M array elements at the sth order, where the sound field information of array element m at the sth order can be expressed as: That is to say, the sound field information of array element m at the sth order is the conjugate of the characteristic coefficient corresponding to array element m in the initial eigenvector of the sth order and the signal received by element m at the first moment The product of .

[0072] In the summation process of formula (17), for two axisymmetric array elements, namely, array element m and array element Mm, , the sum of the sound field information of the two axisymmetric array elements at the sth order can be expressed as: (18) Will Substitute into formula (18) and use Euler's formula Expand formula (18): (19) Based on the formula , we can know that: (20) (twenty one) (twenty two) (twenty three) Below, according to 、 、 ,right and Simplify, the simplification process can be as follows: (twenty four) (25) Obviously, , .

[0073] In this way, the sum of the sound field information of the two axisymmetric array elements at the sth order can be transformed as follows: (26) Because the signals received by the two axisymmetric array elements at the first moment are similar, the difference in the signals received by the two axisymmetric array elements at the first moment is very small and much smaller than the sum of the signals received by the two axisymmetric array elements at the first moment. Therefore, in the above summation process, the imaginary part of the difference in the signals received by the two axisymmetric array elements at the first moment can be ignored. This ensures computational accuracy while omitting the imaginary number and thus reducing complex number operations.

[0074] In this way, the sum of the sound field information of the two axisymmetric array elements at the sth order can be expressed as: (27) In the summation process of formula (17), for array element 0, since array element 0 is located on the X-axis, , , therefore, the sound field information of array element 0 at the sth order Can be: (28) Obviously, since the imaginary part of the characteristic coefficient corresponding to element 0 is 0, the imaginary part of the characteristic coefficient corresponding to element 0 can be omitted. In this way, when calculating the sound field information of element 0 at the sth order, In the process, the imaginary part of the characteristic coefficient corresponding to the array element 0 can be omitted to omit the imaginary number operation, thereby reducing the complex number operation.

[0075] In the summation process of formula (17), for array element M / 2, since array element M / 2 is located on the X-axis, , Therefore, the sound field information of array element M / 2 at the sth order is Can be: (29) Obviously, since the imaginary part of the characteristic coefficient corresponding to the array element M / 2 is 0, the imaginary part of the characteristic coefficient corresponding to the array element M / 2 can be omitted. In this way, when determining the sound field information of the array element M / 2 at the sth order, In the process, the imaginary part of the characteristic coefficient corresponding to the array element M / 2 can be omitted, thereby omitting the imaginary number operation and reducing the complex number operation.

[0076] In summary, from formula (27) to formula (29), we can see that the characteristic coefficient corresponding to the array element m is from becomes That is to say, in the calculation process, we can ignore The imaginary part of . In this way, the initial eigenvector of order s can be removed The imaginary part of each characteristic coefficient in is used to obtain the target characteristic vector of order s , to convert the initial eigenvector of order s from complex numbers to real numbers, so that in the calculation process, by Replace with , reducing complex number operations.

[0077] Among them, the target feature vector of order s is It can be expressed as: (30) in, .

[0078] Next, substitute formula (30) into formula (1) to obtain: (31) Will Substituting into formula (31) we can get: (32) because and is 90°, so . And because ,therefore, Can be transformed into , the transformation process can be shown as follows: (33) because (i.e. the cosine difference angle formula), therefore, It can be expressed as: .

[0079] So, according to and Euler's formula, make the following transformation on formula (32): (34) In the summation process of formula (34), for two centrosymmetric array elements, i.e., array element m and array element M / 2+m, the sum of the sound field information of the two centrosymmetric array elements at the sth order can be expressed as: (35) Based on the above, we can know that: ,

[0080] From the above two formulas, we can see that , so, substituting the relationship between the horizontal azimuth angles of the two centrosymmetric array elements into the above formula (35) we can get formula (36): (36) because , therefore, formula (36) can be simplified as: (37) When s is an even number, , therefore, formula (37) can be simplified as: (38) because , and when s is an even number, , therefore, formula (38) can be transformed into: (39) because , therefore, formula (39) can be expressed as: (40) Obviously, when s is an even number, in the process of calculating the sum of the sound field information of the two centrosymmetric array elements at the sth order, the imaginary parts of the response components corresponding to the two centrosymmetric array elements cancel each other out. In other words, the response component corresponding to the array element m is from becomes . This can be done by removing the initial response matrix The imaginary part of each response component in , resulting in an even-order response matrix ,in, for , in the case that s is an even number, the initial response matrix is ​​converted into a real number, so that in the calculation process, by using replace , in order to reduce complex operations while ensuring calculation accuracy.

[0081] When s is an odd number, , and because , therefore, formula (37) can be simplified as: (41) Since when s is an odd number, , , so we can get: (42) Thus, formula (41) can be converted into: (43) because , so formula (43) can be transformed into: (44) Since the sound field information of the array element at the sth order is used to indicate the signal reception response in all directions, and the signal reception response is associated with the signal output amplitude in all directions, in formula (44), due to the imaginary unit Indicates direction and has nothing to do with amplitude, so the imaginary unit can be Omitted. Thus, formula (44) can be expressed as: (45) Obviously, since the s-th order sound field information is used to indicate the signal reception response in all directions, and the signal reception response is associated with the signal output amplitude in all directions, the imaginary unit Indicates direction, not magnitude, so remove the imaginary unit It will not affect the accuracy of the calculation results.

[0082] Based on this, when s is an odd number, in the process of calculating the sum of the sound field information of the two centrosymmetric array elements at the sth order, the real parts of the response components corresponding to the two centrosymmetric array elements cancel each other out, and the imaginary units in the imaginary parts of the response components corresponding to the two centrosymmetric array elements can be removed. In other words, the response component corresponding to the array element m is from becomes . This can be done by removing the initial response matrix The real part and imaginary unit of each response component in , get the odd-order response matrix ,in, for , in the case that s is an odd number, the initial response matrix is ​​converted into a real number, so that in the calculation process, by using replace , in order to reduce complex operations while ensuring calculation accuracy.

[0083] In summary, the even-order response matrix It can be expressed as: (46) Odd-order response matrix It can be expressed as: (47) Based on the above description, in order to reduce complex operations while ensuring the accuracy of calculation, the target eigenvector of order s can be used , the incident signal at the first moment and the even-order response matrix or the odd-order response matrix determine the s-th order sound field information.

[0084] Specifically, when s is an even number, the sound field information of the sth order It can be determined by the following formula: (48) in, , In the case of an even order, the signal received by each array element in the uniform circular boost sensor array at the first moment.

[0085] Specifically, when s is an odd number, the s-th order sound field information It can be determined by the following formula: (49) in, , In the case of an odd order, the signal received by each array element in the uniform circular boost sensor array at the first moment.

[0086] In addition, the Jacobi-Anger expansion can be used to further simplify Formula (48) and Formula (49) to further reduce the amount of calculation, thereby improving the calculation efficiency and further improving the efficiency of extracting sound field information. The Jacobi-Anger expansion includes: (50) (51) Specifically, the simplified process of formula (48) can be shown as follows: By using formula (50), To expand, the expansion process can be as follows: (52) in, is the nth-order cylindrical Bessel function of the first kind.

[0087] because It has nothing to do with m, so we can In advance, formula (52) becomes formula (53): (53) because Therefore, the following transformation is made to formula (53): (54) because , , therefore, make the following transformation to formula (54): (55) Because in and When taking any value, and ,in, is a constant. Therefore, formula (55) can be transformed into: (56) Since when s is not 0, , when s is 0, ,in, is a constant.

[0088] Thus, due to is a constant, so when s is not 0, Thus, when s is not 0, formula (56) can be simplified to: (57) Continue to use when s is not 0, According to the principle of , in formula (57), n is an integer greater than 0, and s is an integer greater than 0, therefore, Must be an integer greater than 0. . Thus, formula (57) can be simplified to: (58) Continue to use when s is not 0, , when s is 0, The principle of hour, , ,exist hour, , Therefore, when s is a non-zero even number and In the case of , the result of formula (58) is 0. When s is a non-zero even number and In the case of , formula (58) is valid (that is, formula (58) works).

[0089] Thus, when s is a non-zero even number, Substituting into formula (58), formula (58) can be transformed into formula (59): (59) in, is a cylindrical Bessel function of the first kind of order s.

[0090] Obviously, when s is a non-zero even number, the s-th order sound field information It can be expressed as: (60) Since the sound field information is used to indicate the signal reception response in all directions, and the signal reception response is associated with the signal output amplitude in all directions, Indicates direction, not amplitude, so remove It will not affect the accuracy of the calculation results. In this way, when s is a non-zero even number, the sound field information of the sth order It can be expressed as: (61) Since when s is 0, , and when s is 0, and ,therefore, , , therefore, when s is 0, formula (56) can be transformed into: (62) Obviously, when s is 0, the s-th order sound field information It can be expressed as: (63) Since when s is 0, , so when s is 0, by replacing 0 with s in formula (63) and increasing , when s is 0, the s-th order sound field information Transformed into: (64) The simplified process of formula (49) can be shown as follows: By using formula (51), To expand, the expansion process can be as follows: (65) in, is the nth-order cylindrical Bessel function of the first kind.

[0091] because It has nothing to do with m, so we can In advance, formula (65) is transformed into formula (66): (66) because , therefore, make the following transformation to formula (66): (67) because , , therefore, make the following transformation to formula (67): (68) Use in and When taking any value, and According to the principle of , formula (68) is simplified to formula (69): (69) Continue to use when s is not 0, ,in, The principle of being a constant. Since n is an integer greater than zero and s is an odd number, ,so, In this way, formula (69) can be simplified to formula (70): (70) Continue to use when s is not 0, , when s is 0, ,in, The principle of being a constant. hour, ,therefore, . And because hour, ,therefore, Obviously, only When , formula (70) is valid.

[0092] Thus, when s is an odd number, Substituting into formula (70), formula (70) can be transformed into formula (71): (71) Since the sound field information is used to indicate the signal reception response in all directions, and the signal reception response is associated with the signal output amplitude in all directions, Indicates direction, not amplitude, so remove It will not affect the accuracy of the calculation results. In this way, when s is an odd number, the sound field information of the sth order It can be expressed as: (72) In summary, according to formulas (61), (64) and (72), under different values ​​of s, the s-th order sound field information The calculation formula is the same. Therefore, the calculation formula of the s-th order sound field information can be simplified from formula (48) and formula (49) to formula (73) through the Jacobi-Anger expansion. Formula (73) is as follows: (73) Among them, here .

[0093] Obviously, determining the s-th order sound field information by formula (73) can reduce the amount of calculation and the occupation of computing resources, further improve the efficiency of determining the s-th order sound field information, and ensure the accuracy of the calculation results in the simplification process.

[0094] After the calculation formula of the s-th order sound field information is determined, the following describes how to determine the s-th order eigenbeam.

[0095] Eigenbeam of order s It can be calculated by the following formula: (74) in, It is a parameter that ensures the beam pointing direction response is 1. is the initial eigenvalue corresponding to the target eigenvector of order s, , It should be noted that the initial eigenvalue corresponding to the s-th order initial eigenvector is the initial eigenvalue corresponding to the s-th order target eigenvector.

[0096] It should be noted that when the s-th order sound field information is calculated by formula (73), , The expected direction.

[0097] When even-order sound field information is calculated using formula (48): , where s is an even number.

[0098] When calculating odd-order sound field information using formula (49): , where s is an odd number.

[0099] is the s-th order sound field information in the desired direction, is the sound field information of the Ms-th order in the desired direction. The calculation principle and The calculation principle is the same as that of , which will not be described here.

[0100] On this basis, Euler's formula is used to The calculation formula is expanded, and the expansion process can be shown as follows: (75) In the above summation process, for two axially symmetric array elements, namely, element m and element Mm, the summation formula can be expressed as: (76) in, .

[0101] because , , , therefore, formula (76) can be transformed as follows: (77) Since the noise cross-spectral matrix is a circulant matrix, so the value of a is In the case of Thus, formula (77) can be transformed as follows: (78) because , , therefore, make the following transformation to formula (78): (79) Obviously, in the summation process of formula (75), the imaginary parts of the two axisymmetric array elements cancel each other out, so The imaginary part of is removed.

[0102] When the values ​​of m and a are 0, , so that when the values ​​of m and a are 0, The calculation process can be shown as follows: (80) Obviously, when the values ​​of m and a are 0, due to ,therefore, The imaginary part of is also zero, so we can The imaginary part of is removed.

[0103] The values ​​of m and a are In case, , so that the values ​​of m and a are In the case of The calculation process can be shown as follows: (81) Obviously, when the values ​​of m and a are In the case of ,therefore, The imaginary part of is also zero, so we can The imaginary part of is removed.

[0104] In summary, based on formula (78), formula (80) and formula (81), formula (75) can be simplified to: (82) in, .

[0105] Obviously, through the above principle, From the plural form Convert to real number form , and from the above, we can see that this transformation process will not affect the accuracy of the calculation.

[0106] This way, you can remove The imaginary part in ,in, , is the target eigenvalue corresponding to the target eigenvector of order s.

[0107] Thus, when calculating the s-th order eigenbeam In the process of Replace with , reducing complex operations and improving computational efficiency, thereby improving the efficiency of determining the s-th order characteristic beam.

[0108] Specifically, the s-th order eigenbeam It can be calculated by the following formula: (83) Furthermore, due to ,therefore, , and then we can get, . Thus, combined with the above formula, we can know that , .

[0109] Also because, ,therefore, .

[0110] In summary, due to , , , therefore, formula (83) can be transformed into: (84) in, .

[0111] Obviously, since the target eigenvector of the sth order is the same as the target eigenvector of the Msth order, and the target eigenvalue corresponding to the target eigenvector of the sth order is the same as the target eigenvalue corresponding to the target eigenvector of the Msth order, Formula (83) can be simplified to Formula (84). In this way, determining the eigenbeam of the sth order through Formula (84) can improve the efficiency of determining the characteristic wavenumber.

[0112] The formula for determining the composite beam is: (85) Where s is 0~ At least one value in is the synthetic beam, is the s-th order eigenbeam.

[0113] Based on the above description, if Figure 2 As shown, a real-number weighted high-order sound field information extraction and beamforming method provided in an embodiment of the present application may include: 201. Determine the s-th order sound field information based on the s-th order target eigenvector and the signal received by each array element in the uniform circular sound pressure sensor array at the first moment, and use the sound field information of all orders as high-order sound field information; in, , the uniform circular sound pressure sensor array includes M array elements, M is an even number; the uniform circular sound pressure sensor array is placed in the xoy plane and the center of the uniform circular sound pressure sensor array is located at the coordinate origin; array element 0 and array element M / 2 are located on the X axis; 202. When s is 0 or M / 2, determine the s-th order eigenbeam based on the s-th order sound field information, the target eigenvalue corresponding to the s-th order target eigenvector, and the desired direction; 203. For 1≤s≤M / 2-1, determine an s-th order eigenbeam based on the s-th order sound field information, the target eigenvalue corresponding to the s-th order target eigenvector, the Ms-th order sound field information, the target eigenvalue corresponding to the Ms-th order target eigenvector, and the desired direction; 204. Determine a composite beam based on at least one order eigenbeam; The target eigenvector of the sth order is obtained by removing the imaginary part of each eigencoefficient in the initial eigenvector of the sth order; The initial eigenvector of the sth order includes characteristic coefficients corresponding to the M array elements one by one, and each characteristic coefficient is used to indicate the weight of the signal of the corresponding array element at the sth order; The imaginary part of each eigenvalue coefficient in the s-th order initial eigenvalue vector is determined in the process of determining the s-th order sound field information of each array element according to the eigenvalue coefficient corresponding to each array element in the s-th order initial eigenvalue vector and the signal received by each array element at the first moment, and summing the sound field information of all array elements at the s-th order to obtain the s-th order sound field information. The imaginary part of each eigenvalue coefficient in the s-th order initial eigenvalue vector of the two axially symmetric array elements in the uniform circular sound pressure sensor array is multiplied by the difference between the signals received by the two axially symmetric array elements at the first moment, and the signals received by the two axially symmetric array elements at the first moment are similar. In addition, the imaginary parts of the eigenvalue coefficients corresponding to the array elements 0 and the array elements M / 2 in the s-th order initial eigenvalue vector are made zero and removed in combination with the fact that the array elements 0 and the array elements M / 2 are located on the X-axis.

[0114] Obviously, since the s-th order target eigenvector is obtained by removing the imaginary part of each eigencoefficient in the s-th order initial eigenvector, that is, the s-th order target eigenvector is a real number. Therefore, according to the s-th order target eigenvector and the signal received by each array element in the uniform circular sound pressure sensor array at the first moment, the s-th order sound field information is determined, which can reduce complex operations, thereby reducing memory usage and calculation time, and improving calculation efficiency and the efficiency of determining the s-th order sound field information. In this way, since high-order sound field information is a collection of sound field information of all orders, the efficiency of extracting high-order sound field information is improved. Based on this, for s being 0 or M / 2, the s-th order eigenbeam is determined according to the s-th order sound field information, the target eigenvalue corresponding to the s-th order target eigenvector, and the expected direction. For 1≤s≤M / 2-1, the s-th order characteristic beam is determined according to the s-th order sound field information, the target eigenvalue corresponding to the s-th order target eigenvector, the Ms-th order sound field information, the target eigenvalue corresponding to the Ms-th order target eigenvector and the expected direction, and the synthetic beam is determined according to at least one order characteristic beam, thereby improving the efficiency of beam synthesis.

[0115] Furthermore, since the imaginary part of each eigenvalue in the s-th order initial eigenvector is determined based on the eigenvalue corresponding to each element in the s-th order initial eigenvector and the signal received by each element at the first moment, and the sound field information of all elements at the s-th order is summed to obtain the s-th order sound field information, the imaginary part of each eigenvalue in the eigenvalue corresponding to each element in the s-th order initial eigenvector is multiplied by the difference between the signals received by the two axially symmetric elements at the first moment, and the signals received by the two axially symmetric elements at the first moment are similar, and the imaginary part of the eigenvalue corresponding to each element in the s-th order initial eigenvector is zero and is removed based on the fact that element 0 and element M / 2 are located on the X-axis. Therefore, by removing the imaginary part of each eigenvalue in the s-th order initial eigenvector, the s-th order target eigenvector is obtained, thereby ensuring the accuracy of the s-th order target eigenvector, thereby ensuring the accuracy of high-order sound field information extraction and beamforming.

[0116] Optionally, determining the s-th order sound field information according to the s-th order target eigenvector and the signal received by each array element in the uniform circular sound pressure sensor array at the first moment includes: When s is an even number, the s-th order sound field information is determined according to the s-th order target eigenvector, the even-order response matrix and the incident signal at the first moment; when s is an odd number, the s-th order sound field information is determined according to the s-th order target eigenvector, the odd-order response matrix and the incident signal at the first moment; wherein the even-order response matrix is ​​obtained by removing the imaginary part of each response component in the initial response matrix; the odd-order response matrix is ​​obtained by removing the real part and the imaginary unit of each response component in the initial response matrix; the initial response matrix includes response components corresponding to M array elements one by one, each response component is used to indicate the gain and phase deviation of the corresponding array element to the signal in the first incident direction, and the first incident direction is the direction of the incident signal; the imaginary part of each response component in the initial response matrix is ​​determined according to the characteristic coefficients corresponding to each array element in the s-th order target eigenvector, the response components corresponding to each array element in the initial response matrix and the incident signal at the first moment In the process of obtaining the s-th order sound field information of each array element and summing the s-th order sound field information of all array elements, the imaginary parts of the response components corresponding to the two centrally symmetrical array elements in the uniform circular sound pressure sensor array in the initial response matrix are canceled out and removed; the real part and the imaginary unit of each response component in the initial response matrix are determined based on the characteristic coefficients corresponding to each array element in the s-th order target eigenvector, the response components corresponding to each array element in the initial response matrix, and the incident signal at the first moment, and the s-th order sound field information of all array elements is summed out to obtain the s-th order sound field information. In the process of obtaining the s-th order sound field information, the real parts of the response components corresponding to the two centrally symmetrical array elements in the uniform circular sound pressure sensor array in the initial response matrix are canceled out, and combined with the s-th order sound field information to indicate the signal reception response in all directions, and the signal reception response is associated with the signal output amplitude in all directions and removed.

[0117] Optionally, the initial eigenvector of the sth order is:

[0118] in, is the initial eigenvector of order s, for The characteristic coefficient corresponding to the array element m, , is the horizontal azimuth angle of array element m, Indicates transposition, is the imaginary unit, s is the order; The target feature vector of the sth order is:

[0119] in, , is the target feature vector of order s, for The characteristic coefficient corresponding to the array element m.

[0120] Optionally, the initial response matrix is:

[0121] in, is the initial response matrix, for The response component corresponding to the array element m, , is the wave number, is the unit vector of the propagation direction of the incident signal at the first moment, is the coordinate of array element m in the rectangular coordinate system, is the imaginary unit, Indicates transposition, θ and are the vertical pitch angle and horizontal azimuth angle of the incident signal at the first moment respectively; The even-order response matrix is:

[0122] in, is an even-order response matrix, , for The response component corresponding to the array element m, is the horizontal azimuth angle of array element m, r is the straight-line distance between array element m and the coordinate axis point; The odd-order response matrix is:

[0123] in, is an odd-order response matrix, , for The response component corresponding to the array element m.

[0124] Optionally, when s is an even number, determining the s-th order sound field information according to the s-th order target eigenvector, the even-order response matrix, and the incident signal at the first moment includes: When s is an even number, the s-th order sound field information is determined by the following formula:

[0125] in, is the s-th order sound field information, is the characteristic coefficient corresponding to the array element m in the target eigenvector of order s, is the incident signal at the first moment; When s is an odd number, determining the s-th order sound field information according to the s-th order target eigenvector, the odd-order response matrix, and the incident signal at the first moment includes: When s is an odd number, the s-th order sound field information is determined by the following formula: .

[0126] Optionally, the method further includes: The formula for determining the even-order sound field information and the formula for determining the odd-order sound field information are transformed into the following formulas through the Jacobi-Anger expansion:

[0127] in, is a cylindrical Bessel function of the first kind of order s.

[0128] Optionally, for s being 0 or M / 2, determining the s-th order eigenbeam according to the s-th order sound field information, the target eigenvalue corresponding to the s-th order target eigenvector, and the expected direction includes: The eigenbeam of order s is determined by the following formula:

[0129] in, , is the s-th order eigenbeam, It is a parameter that ensures the beam pointing direction response is 1. is the target eigenvalue corresponding to the target eigenvector of order s, For the expected direction, is the s-th order sound field information in the desired direction, is the sth order sound field information, θ and are the vertical pitch angle and horizontal azimuth angle of the incident signal at the first moment respectively; For 1≤s≤M / 2-1, determining the s-th order eigenbeam according to the s-th order sound field information, the target eigenvalue corresponding to the s-th order target eigenvector, the Ms-th order sound field information, the target eigenvalue corresponding to the Ms-th order target eigenvector, and the expected direction includes: The eigenbeam of order s is determined by the following formula:

[0130] in, , is the s-th order eigenbeam, It is a parameter that ensures the beam pointing direction response is 1. is the target eigenvalue corresponding to the target eigenvector of order s, For the expected direction, is the s-th order sound field information in the desired direction, is the s-th order sound field information, is the target eigenvalue corresponding to the target eigenvector of the Ms order, is the sound field information of the Ms-th order in the desired direction, is the Ms-th order sound field information, θ and are the vertical pitch angle and horizontal azimuth angle of the incident signal at the first moment respectively; The target eigenvalue corresponding to the target eigenvector of the sth order is obtained by removing the imaginary part of the initial eigenvalue corresponding to the target eigenvector of the sth order;

[0131] in, is the target eigenvalue corresponding to the target eigenvector of order s, , , is the array element m and the array element The noise correlation between , , , is the horizontal azimuth angle of array element m;

[0132] in, is the initial eigenvalue corresponding to the target eigenvector of order s; The imaginary part of the initial eigenvalue corresponding to the target eigenvector of order s is based on m being 0 and make The imaginary part of is 0, and combined with , The two axially symmetric elements The imaginary parts of the sum cancel each other out and are removed.

[0133] Optionally, the method further includes: Based on the fact that the target eigenvector of the sth order is the same as the target eigenvector of the Msth order and the target eigenvalue corresponding to the target eigenvector of the sth order is the same as the target eigenvalue corresponding to the target eigenvector of the Msth order, the formula for determining the eigenbeam of the sth order is transformed into:

[0134] in, .

[0135] Optionally, determining a synthetic beam based on at least a first-order eigenbeam includes: The composite beam is determined by the following formula:

[0136] Where s is 0~ At least one of is the synthetic beam, is the sth order characteristic beam, θ and are the vertical pitch angle and horizontal azimuth angle of the incident signal at the first moment respectively.

[0137] It should be noted that the implementation methods and principles of the above steps have been explained above and will not be repeated here.

[0138] Below, a simulation comparison is performed between the high-order sound field information extraction and beamforming method for real number weighted processing provided in the embodiment of the present application and the sound field information of each order in the desired direction determined by the characteristic beam decomposition and synthesis theory in the related art to verify the consistency of the high-order sound field information extraction and beamforming method for real number weighted processing provided in the embodiment of the present application and the characteristic beam decomposition and synthesis theory in the related art.

[0139] The simulation results are as follows Figure 3 As shown, Figure 3 (a) is a comparison diagram of the 0th-order sound field information in the desired direction. Figure 3 (b) is a schematic diagram of the comparison of the first-order sound field information in the desired direction. Figure 3 (c) is a comparative diagram of the second-order sound field information in the desired direction. Figure 3 (d) is a comparative diagram of the third-order sound field information in the desired direction. Figure 3 (e) is a comparative diagram of the 5th order sound field information in the desired direction. In the simulation, the receiving array is set to an 8-element uniform circular sound pressure sensor array with a diameter of 0.2 meters, the desired signal frequency is 500Hz, and the direction of the desired signal (i.e., the desired direction) is set to .

[0140] Depend on Figure 3 It can be seen that the sound field information of each order in the desired direction determined by the embodiment of the present application is compared with the sound field information of each order in the desired direction determined by the characteristic beam decomposition and synthesis theory in the related art. Under the condition of , the two methods obtain the sound field information of each order in the desired direction with good consistency, indicating that the high-order sound field information extraction and beamforming method with real number weighting processing provided in the embodiment of the present application can accurately extract high-order modal sound field information.

[0141] Since the original analog signal collected by the actual uniform circular sound pressure sensor array receiving system is in real number form, we further considered the simulation analysis of the received single-frequency signal. The simulation generated a single-frequency signal with a signal frequency of 500Hz, a sampling frequency set to 16kHz, and a signal incident direction ranging from 0° to 360°. In combination with the solution provided in the embodiment of the application, the simulated signal is directly processed by real number weighted summation to obtain the sound field information output of each order in different directions. Figure 4 (a) is the response diagram of the maximum value of the 0th order sound field information output in different directions. Figure 4 (b) is the response diagram of the maximum value of the first-order sound field information output in different directions. Figure 4 (c) is the response diagram of the maximum value of the second-order sound field information output in different directions. Figure 4 (d) is the response diagram of the maximum value of the third-order sound field information output in different directions. Figure 4 Figure (e) shows the maximum output response of the fourth-order sound field information in different directions. It can be seen that after the simulated signal undergoes real-number weighted summation processing, its spatial output response in different directions maintains good consistency with the spatial directivity of the theoretical sound field information in real-number form, verifying the effectiveness of this embodiment in processing actual array receive signals.

[0142] Based on the comparative simulation of the eigenbeam obtained by real number weighted processing (i.e., the embodiment of the present application) and the eigenbeam obtained by the eigenbeam decomposition and synthesis model, a comparative simulation of the synthetic beam obtained by real number weighted processing and the synthetic beam obtained by the existing eigenbeam decomposition and synthesis model is further obtained. Figure 5 (a) is a comparative diagram of the synthetic beam determined by the 0th-order eigenbeam. Figure 5 (b) is a comparative diagram of the synthetic beam determined by the 0th-order and 1st-order eigenbeams. Figure 5 (c) is a comparative diagram of the synthetic beam determined by the eigenbeams of order 0 to 2. Figure 5 (d) is a comparative diagram of the synthetic beam determined by the eigenbeams of order 0 to 3. Figure 5 (e) is a comparative diagram of the synthesized beams determined by the eigenbeams of order 0 to 4. It can be seen that the spatial responses of the synthesized beams of the two methods are also highly consistent.

[0143] Here, the computational costs of the embodiments of the present application and the two methods of eigenbeam decomposition and synthesis are compared and analyzed. Considering actual engineering applications, complex number calculations require the storage of real and imaginary parts, which is equivalent to twice the amount of real data, and the memory usage in matrix operations is significantly increased. Specifically, complex number addition and subtraction operations need to be performed on the real and imaginary parts respectively, and the amount of calculation is twice that of real number operations under the same circumstances. A complex number multiplication operation includes 4 real number multiplications and 2 addition operations, while a real number multiplication operation only requires 1. Taking the eigenbeam solution as an example, the embodiment of the present application adopts a real number weighted processing method compared to the eigenbeam decomposition and synthesis method, which can save the calculation process of the complex part of the weighting coefficient, so the amount of calculation of the present invention is reduced to half of the original method. Therefore, the embodiment of the present application adopts a real number weighted processing method, which can greatly reduce the computational complexity in actual engineering applications and effectively improve the computational efficiency of the real-time processing system. In practical applications, the embodiments of the present application can achieve real-time and accurate acquisition of high-order modal sound field information by reasonably designing a combined operational amplifier for analog addition and subtraction. It is simple and easy to implement, and provides a theoretical basis for the subsequent effective use of high-order sound field information.

[0144] The above content is only a specific embodiment of this application, but the scope of protection of this application is not limited to this. Any changes or replacements within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A real-number weighted high-order sound field information extraction and beamforming method, characterized in that: include: Determine the s-th order sound field information based on the s-th order target eigenvector and the signal received by each array element in the uniform circular sound pressure sensor array at the first moment, and use the sound field information of all orders as high-order sound field information; in, , the uniform circular sound pressure sensor array includes M array elements, M is an even number; the uniform circular sound pressure sensor array is placed in the xoy plane and the center of the uniform circular sound pressure sensor array is located at the coordinate origin; array element 0 and array element M / 2 are located on the X axis; When s is 0 or M / 2, the s-th order eigenbeam is determined based on the s-th order sound field information, the target eigenvalue corresponding to the s-th order target eigenvector, and the desired direction; For 1≤s≤M / 2-1, determine the s-th order eigenbeam based on the s-th order sound field information, the target eigenvalue corresponding to the s-th order target eigenvector, the Ms-th order sound field information, the target eigenvalue corresponding to the Ms-th order target eigenvector, and the desired direction; determining a composite beam based on at least a first-order eigenbeam; The target eigenvector of the sth order is obtained by removing the imaginary part of each eigencoefficient in the initial eigenvector of the sth order; The initial eigenvector of the sth order includes characteristic coefficients corresponding to the M array elements one by one, and each characteristic coefficient is used to indicate the weight of the signal of the corresponding array element at the sth order; The imaginary part of each eigenvalue coefficient in the s-th order initial eigenvalue vector is determined in the process of determining the s-th order sound field information of each array element according to the eigenvalue coefficient corresponding to each array element in the s-th order initial eigenvalue vector and the signal received by each array element at the first moment, and summing the sound field information of all array elements at the s-th order to obtain the s-th order sound field information. The imaginary part of each eigenvalue coefficient in the s-th order initial eigenvalue vector of the two axially symmetric array elements in the uniform circular sound pressure sensor array is multiplied by the difference between the signals received by the two axially symmetric array elements at the first moment, and the signals received by the two axially symmetric array elements at the first moment are similar. In addition, the imaginary parts of the eigenvalue coefficients corresponding to the array elements 0 and the array elements M / 2 in the s-th order initial eigenvalue vector are made zero and removed in combination with the fact that the array elements 0 and the array elements M / 2 are located on the X-axis.

2. The method according to claim 1, characterized in that Determining the s-th order sound field information according to the s-th order target eigenvector and the signal received at the first moment by each array element in the uniform circular sound pressure sensor array includes: When s is an even number, the s-th order sound field information is determined according to the s-th order target eigenvector, the even-order response matrix and the incident signal at the first moment; When s is an odd number, the s-th order sound field information is determined according to the s-th order target eigenvector, the odd-order response matrix and the incident signal at the first moment; Among them, the even-order response matrix is ​​obtained by removing the imaginary part of each response component in the initial response matrix; The odd-order response matrix is ​​obtained by removing the real part and imaginary unit of each response component in the initial response matrix; The initial response matrix includes response components corresponding one-to-one to the M array elements, each response component is used to indicate the gain and phase deviation of the corresponding array element to a signal in a first incident direction, where the first incident direction is the direction of the incident signal; The imaginary part of each response component in the initial response matrix is ​​removed by canceling out the imaginary parts of the response components corresponding to two centrosymmetric array elements in the uniform circular sound pressure sensor array in the initial response matrix in a process of determining the s-th order sound field information of each array element based on the characteristic coefficient corresponding to each array element in the s-th order target eigenvector, the response component corresponding to each array element in the initial response matrix, and the incident signal at the first moment, and summing the s-th order sound field information of all array elements to obtain the s-th order sound field information; The real part and the imaginary unit of each response component in the initial response matrix are determined in the process of determining the s-th order sound field information of each array element based on the characteristic coefficient corresponding to each array element in the s-th order target eigenvector, the response component corresponding to each array element in the initial response matrix, and the incident signal at the first moment, and summing the s-th order sound field information of all array elements to obtain the s-th order sound field information. The real parts of the response components corresponding to two centrally symmetrical array elements in the uniform circular sound pressure sensor array in the initial response matrix cancel each other out, and are removed in combination with the s-th order sound field information to indicate the signal reception response in all directions, and the signal reception response is associated with the signal output amplitude in all directions.

3. The method according to claim 1, characterized in that The initial eigenvector of the sth order is: in, is the initial eigenvector of order s, for The characteristic coefficient corresponding to the array element m, , is the horizontal azimuth angle of array element m, Indicates transposition, is the imaginary unit, s is the order; The target feature vector of the sth order is: in, , is the target feature vector of order s, for The characteristic coefficient corresponding to the array element m.

4. The method according to claim 2, characterized in that The initial response matrix is: in, is the initial response matrix, for The response component corresponding to the array element m, , is the wave number, is the unit vector of the propagation direction of the incident signal at the first moment, is the coordinate of array element m in the rectangular coordinate system, is the imaginary unit, Indicates transposition, and are the vertical pitch angle and horizontal azimuth angle of the incident signal at the first moment respectively; The even-order response matrix is: in, is an even-order response matrix, , for The response component corresponding to the array element m, is the horizontal azimuth angle of array element m, r is the straight-line distance between array element m and the coordinate axis point; The odd-order response matrix is: in, is an odd-order response matrix, , for The response component corresponding to the array element m.

5. The method according to claim 4, characterized in that When s is an even number, determining the s-th order sound field information according to the s-th order target eigenvector, the even-order response matrix, and the incident signal at the first moment includes: When s is an even number, the s-th order sound field information is determined by the following formula: in, is the s-th order sound field information, is the characteristic coefficient corresponding to the array element m in the target eigenvector of order s, is the incident signal at the first moment; When s is an odd number, determining the s-th order sound field information according to the s-th order target eigenvector, the odd-order response matrix, and the incident signal at the first moment includes: When s is an odd number, the s-th order sound field information is determined by the following formula: 。 6. The method according to claim 5, characterized in that The method further comprises: The formula for determining the even-order sound field information and the formula for determining the odd-order sound field information are transformed into the following formulas through the Jacobi-Anger expansion: in, is a cylindrical Bessel function of the first kind of order s.

7. The method according to claim 1, characterized in that The determining of the s-th order eigenbeam according to the s-th order sound field information, the target eigenvalue corresponding to the s-th order target eigenvector, and the expected direction when s is 0 or M / 2 includes: The eigenbeam of order s is determined by the following formula: in, , is the s-th order eigenbeam, It is a parameter that ensures the beam pointing direction response is 1. is the target eigenvalue corresponding to the target eigenvector of order s, For the expected direction, is the s-th order sound field information in the desired direction, is the sth order sound field information, θ and are the vertical pitch angle and horizontal azimuth angle of the incident signal at the first moment respectively; For 1≤s≤M / 2-1, determining the s-th order eigenbeam according to the s-th order sound field information, the target eigenvalue corresponding to the s-th order target eigenvector, the Ms-th order sound field information, the target eigenvalue corresponding to the Ms-th order target eigenvector, and the expected direction includes: The eigenbeam of order s is determined by the following formula: in, , is the s-th order eigenbeam, It is a parameter that ensures the beam pointing direction response is 1. is the target eigenvalue corresponding to the target eigenvector of order s, For the expected direction, is the s-th order sound field information in the desired direction, is the s-th order sound field information, is the target eigenvalue corresponding to the target eigenvector of the Ms order, is the sound field information of the Ms-th order in the desired direction, is the Ms-th order sound field information, θ and are the vertical pitch angle and horizontal azimuth angle of the incident signal at the first moment respectively; The target eigenvalue corresponding to the target eigenvector of the sth order is obtained by removing the imaginary part of the initial eigenvalue corresponding to the target eigenvector of the sth order; in, is the target eigenvalue corresponding to the target eigenvector of order s, , , is the array element m and the array element The noise correlation between , , , is the horizontal azimuth angle of array element m; in, is the initial eigenvalue corresponding to the target eigenvector of order s; The imaginary part of the initial eigenvalue corresponding to the target eigenvector of order s is based on m being 0 and make The imaginary part of is 0, and combined with , The two axially symmetric array elements The imaginary parts of the sum cancel each other out and are removed.

8. The method according to claim 7, characterized in that The method further comprises: Based on the fact that the target eigenvector of the sth order is the same as the target eigenvector of the Msth order and the target eigenvalue corresponding to the target eigenvector of the sth order is the same as the target eigenvalue corresponding to the target eigenvector of the Msth order, the formula for determining the eigenbeam of the sth order is transformed into: in, .

9. The method according to claim 1, characterized in that Determining the synthesized beam according to at least one first-order eigenbeam includes: The composite beam is determined by the following formula: Where s is 0~ At least one of is the synthetic beam, is the sth order characteristic beam, θ and are the vertical pitch angle and horizontal azimuth angle of the incident signal at the first moment respectively.

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