A method for high-order sound field information extraction and beamforming of real number weighting processing

Abstract

The embodiment of the application provides a high-order sound field information extraction and beam forming method of real number weighting processing, which comprises the following steps: determining the sound field information of the s-th order according to the target characteristic vector of the s-th order and the signal received by each array element at the first moment, and taking the sound field information of all orders as high-order sound field information; determining the characteristic beam of the s-th order according to the sound field information of the s-th order, the target eigenvalue corresponding to the target characteristic vector of the s-th order and the expected direction, wherein s is 0 or M / 2; determining the characteristic beam of the s-th order according to the sound field information of the s-th order, the target eigenvalue corresponding to the target characteristic vector of the s-th order, the sound field information of the M-s-th order, the target eigenvalue corresponding to the target characteristic vector of the M-s-th order and the expected direction, wherein 1≤s≤M / 2-1; and determining the composite beam according to at least one order of characteristic beam. The embodiment of the application can reduce complex operation and improve the efficiency of high-order sound field information extraction and beam forming.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of signal processing, in particular, to a high-order sound field information extraction and beamforming method based on real number weighting processing. BACKGROUND

[0002] In the field of acoustic detection, traditional array technology faces the bottleneck of insufficient directivity and resolution at small size, while super-directivity beamforming technology can break through the physical aperture limit, but its algorithm complexity and computing resource occupation problem restricts the practical application. The characteristic beam decomposition and synthesis theory as an advanced sound field processing method, its core lies in decomposing the complex sound field into basic beams (characteristic beams) with orthogonal characteristics, and realizing target sound field reconstruction through weighted combination. Specifically, this theory uses the spatial correlation of the sound field and eigenvalue decomposition to map the array receiving signal to the orthogonal space composed of characteristic beams, suppresses the interference in the isotropic uniform noise field by extracting the main characteristic beam, and designs the weighting coefficient based on the orthogonal completeness of the characteristic beam to realize directional beam synthesis.

[0003] In particular, for the application scenario of a uniform circular ring-shaped acoustic pressure sensor array in an isotropic noise field, the theory uses the circulant matrix property of the noise cross-spectral matrix to express the optimal beam output as the superposition of a finite-order sub-component, and each order component is defined as a characteristic beam, thereby giving an exact analytical solution of high-order super-directivity. Further, by determining the sound field information of different orders, a high-order sound field sensor theory can be established to provide theoretical support for small-scale uniform circular ring-shaped acoustic pressure sensor arrays to realize high-resolution sound field analysis and beamforming.

[0004] However, the existing characteristic beam decomposition and synthesis theory requires a large number of complex number operations in the implementation process, resulting in high computing resource occupation and long operation time. In particular, when involving multiplication, division and other complex mathematical operations, the real and imaginary parts of the complex number need to be calculated separately, further increasing the computing resource occupation and prolonging the operation time, thereby reducing the efficiency of high-order sound field information extraction and beamforming. SUMMARY

[0005] Embodiments of the present application provide a high-order sound field information extraction and beamforming method based on real number weighting processing, which can reduce complex number operations, thereby reducing computing resource occupation and operation time, improving operation efficiency, and further improving the efficiency of high-order sound field information extraction and beamforming.

[0006] Embodiments of the present application provide a high-order sound field information extraction and beamforming method based on real number weighting processing, which can reduce complex number operations, thereby reducing computing resource occupation and operation time, improving operation efficiency, and further improving the efficiency of high-order sound field information extraction and beamforming.

[0007] According to the target characteristic vector of the s-th order and the signal received by each element in the uniform circular ring-shaped acoustic pressure sensor array at the first time, the s-th order sound field information is determined, and the sound field information of all orders is taken as high-order sound field information; wherein, The uniform circular ring-shaped acoustic pressure sensor array includes M elements, and M is an even number; the uniform circular ring-shaped acoustic pressure sensor array is placed in the x-o-y plane, and the center of the uniform circular ring-shaped acoustic pressure sensor array is located at the coordinate origin; the element 0 and the element M / 2 are located on the X axis; for s being 0 or M / 2, 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 characteristic vector 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 characteristic vector, the M-s-th order sound field information, the target eigenvalue corresponding to the M-s-th order target characteristic vector and the expected direction; the composite beam is determined according to at least one order of characteristic beam; wherein the s-th order target characteristic vector is obtained by removing the imaginary part of each characteristic coefficient in the s-th order initial characteristic vector; the s-th order initial characteristic vector includes characteristic coefficients corresponding to the M elements one by one, and each characteristic coefficient is used to indicate the weight of the signal of the corresponding element at the s-th order; the imaginary part of each characteristic coefficient in the s-th order initial characteristic vector is obtained by multiplying the imaginary part of the corresponding characteristic coefficient in the s-th order initial characteristic vector of the two axisymmetric elements in the uniform circular ring-shaped acoustic pressure sensor array and the difference between the signals received by the two axisymmetric elements at the first time, and the signals received by the two axisymmetric elements at the first time are similar, and the element 0 and the element M / 2 are removed because the imaginary part of the corresponding characteristic coefficient in the s-th order initial characteristic vector of the element 0 and the element M / 2 is zero.

[0008] Optionally, the determining the s-th order sound field information according to the s-th order target characteristic vector and signals received by each element in the uniform circular ring-shaped acoustic pressure sensor array at the first time instant comprises: in a case that s is even, determining the s-th order sound field information according to the s-th order target characteristic vector, an even order response matrix and the incident signal at the first time instant; in a case that s is odd, determining the s-th order sound field information according to the s-th order target characteristic vector, an odd order response matrix and the incident signal at the first time instant; wherein the even order response matrix is obtained by removing an imaginary part of each response component in an initial response matrix; the odd order response matrix is obtained by removing a real part and an imaginary unit of each response component in the initial response matrix; the initial response matrix comprises response components corresponding to the M elements one by one, each response component being used to indicate a deviation of gain and phase of a signal in a first incident direction by a corresponding element, the first incident direction being a direction of the incident signal; the imaginary part of each response component in the initial response matrix is removed based on that the imaginary parts of the corresponding response components of the two center-symmetric elements in the uniform circular ring-shaped acoustic pressure sensor array cancel each other in a process of determining the s-th order sound field information of each element according to the characteristic coefficients corresponding to the elements in the s-th order target characteristic vector, the response components corresponding to the elements in the initial response matrix and the incident signal at the first time instant, and summing the s-th order sound field information of all elements to obtain the s-th order sound field information; the real part of each response component in the initial response matrix and the imaginary unit are removed based on that the real parts of the corresponding response components of the two center-symmetric elements in the uniform circular ring-shaped acoustic pressure sensor array cancel each other, and the s-th order sound field information indicates a signal receiving response in all directions and the signal receiving response is associated with a signal output amplitude in all directions in the process of determining the s-th order sound field information of each element according to the characteristic coefficients corresponding to the elements in the s-th order target characteristic vector, the response components corresponding to the elements in the initial response matrix and the incident signal at the first time instant, and summing the s-th order sound field information of all elements to obtain the s-th order sound field information.

[0009] Optionally, the s-th order initial characteristic vector is:

[0010]

[0011] wherein, is the s-th order initial characteristic vector, is is a characteristic coefficient corresponding to element m in the matrix, , is an azimuth angle of element m, indicates transposition, is an imaginary unit, and s is an order number;

[0012] The target eigenvector of the s-th order is:

[0013]

[0014] wherein, , is the target eigenvector of the s-th order, is is the characteristic coefficient corresponding to the array element m.

[0015] Optionally, the initial response matrix is:

[0016]

[0017] wherein, is the initial response matrix, is is 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 time, is the coordinate of the array element m in the rectangular coordinate system, is the imaginary unit, indicates transposition, θ and are the vertical pitch angle and the horizontal azimuth angle of the incident signal at the first time, respectively;

[0018] The even-order response matrix is:

[0019]

[0020] wherein, is the even-order response matrix, , is is the response component corresponding to the array element m, is the horizontal azimuth angle of the array element m, and r is the straight-line distance between the array element m and the circle point of the coordinate axis;

[0021] The odd-order response matrix is:

[0022]

[0023] wherein, is the odd-order response matrix, , is is the response component corresponding to the array element m.

[0024] Optionally, the 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 time point when s is even comprises:

[0025] The s-th order sound field information is determined by the following formula when s is even:

[0026]

[0027] wherein, is the s-th order sound field information, is a characteristic coefficient corresponding to the element m in the s-th order target eigenvector, is the incident signal at the first time point;

[0028] The 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 time point when s is odd comprises:

[0029] The s-th order sound field information is determined by the following formula when s is odd:

[0030] .

[0031] Optionally, the method further comprises:

[0032] 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 formula by Jacobian-Angel expansion:

[0033]

[0034] wherein, is the s-th order first-type cylindrical Bessel function.

[0035] Optionally, the determining the s-th order characteristic beam according to the s-th order sound field information, a target eigenvalue corresponding to the s-th order target eigenvector and an expected direction when s is 0 or M / 2 comprises:

[0036] The s-th order characteristic beam is determined by the following formula:

[0037]

[0038] wherein, , is the s-th order characteristic beam, is a parameter for ensuring that the response of the beam pointing direction is 1, is a target eigenvalue corresponding to the s-th order target eigenvector, is an expected direction, is the s-th order sound field information in the expected direction, the sound field information of the s-th order, θs and respectively are the vertical elevation angle and the horizontal azimuth angle of the incident signal at the first time;

[0039] The characteristic beam of the s-th order is determined according to the sound field information of the s-th order, the target eigenvalue corresponding to the target eigenvector of the s-th order, the sound field information of the M-s-th order, the target eigenvalue corresponding to the target eigenvector of the M-s-th order, and the expected direction, for 1≤s≤M / 2-1, and the characteristic beam of the s-th order includes:

[0040] The characteristic beam of the s-th order is determined by the following formula:

[0041]

[0042] wherein, , is the characteristic beam of the s-th order, is a parameter for ensuring that the response of the beam pointing direction is 1, is the target eigenvalue corresponding to the target eigenvector of the s-th order, is the expected direction, is the sound field information of the s-th order in the expected direction, is the sound field information of the s-th order, is the target eigenvalue corresponding to the target eigenvector of the M-s-th order, is the sound field information of the M-s-th order in the expected direction, is the sound field information of the M-s-th order, θs and respectively are the vertical elevation angle and the horizontal azimuth angle of the incident signal at the first time;

[0043] The target eigenvalue corresponding to the target eigenvector of the s-th order is obtained by removing the imaginary part in the initial eigenvalue corresponding to the target eigenvector of the s-th order;

[0044]

[0045] wherein, is the target eigenvalue corresponding to the target eigenvector of the s-th order, , , is the noise correlation between the array element m and the array element , , , , is the horizontal azimuth angle of the array element m;

[0046]

[0047] wherein, an initial eigenvalue corresponding to the target eigenvector of the s-th order;

[0048] an imaginary part of the initial eigenvalue corresponding to the target eigenvector of the s-th order is based on m being 0 and making an imaginary part of be 0, and combining , making an imaginary part of of the two array elements symmetrical about an axis be removed by mutual cancellation.

[0049] Optionally, the method further comprises:

[0050] based on the target eigenvector of the s-th order and the target eigenvector of the M-s-th order being the same and the target eigenvalue corresponding to the target eigenvector of the s-th order and the target eigenvalue corresponding to the target eigenvector of the M-s-th order being the same, the formula for determining the s-th order characteristic beam is transformed into:

[0051]

[0052] wherein, .

[0053] Optionally, the determining the synthetic beam according to the at least one order characteristic beam comprises:

[0054] the synthetic beam is determined by the following formula:

[0055]

[0056] wherein, s is 0 at least one of is the synthetic beam, is the s-th order characteristic beam, and are respectively a vertical elevation angle and a horizontal azimuth angle of the incident signal at the first time.

[0057] The real weighted processing high-order sound field information extraction and beam forming method in the embodiments of the present application has the following beneficial effects:

[0058] Since the target eigenvector of the s-th order is obtained by removing the imaginary part of each eigenvalue in the initial eigenvector of the s-th order, that is, the target eigenvector of the s-th order is a real number. Therefore, according to the target eigenvector of the s-th order and the signals received by each element in the uniform circular ring-shaped acoustic pressure sensor array at the first time, the s-th order sound field information is determined, which can reduce the complex operation, thereby reducing the memory occupation and operation time consumption, improving the operation efficiency and the efficiency of determining the s-th order sound field information. Therefore, since the high-order sound field information is the collection of all-order sound field information, the efficiency of extracting the 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 eigenbeam is determined according to the s-th order sound field information, the target eigenvalue corresponding to the s-th order target eigenvector, the (M-s)-th order sound field information, the target eigenvalue corresponding to the (M-s)-th order target eigenvector and the expected direction, and the synthetic beam is determined according to at least one eigenbeam, thereby improving the efficiency of beam synthesis.

[0059] Moreover, since the imaginary part of each eigenvalue in the initial eigenvector of the s-th order is obtained by multiplying the imaginary part of the corresponding eigenvalue in the initial eigenvector of the s-th order with the signals received by the two axially symmetric elements in the uniform circular ring-shaped acoustic pressure sensor array at the first time, and the signals received by the two axially symmetric elements at the first time are similar, and the imaginary part of the corresponding eigenvalue in the initial eigenvector of the s-th order of the element 0 and the element M / 2 is removed because the element 0 and the element M / 2 are located on the X-axis. Therefore, by removing the imaginary part of each eigenvalue in the initial eigenvector of the s-th order, the target eigenvector of the s-th order is obtained, which ensures the accuracy of the target eigenvector of the s-th order, and further ensures the accuracy of the high-order sound field information extraction and beam synthesis. BRIEF DESCRIPTION OF DRAWINGS

[0060] Figure 1 It is a structural schematic diagram of the uniform circular ring-shaped acoustic pressure sensor array;

[0061] Figure 2 It is a flowchart of a real number weighting processing high-order sound field information extraction and beam forming method provided by the embodiment of the application;

[0062] Figure 3 Fig. (a) is a comparative schematic diagram of the 0-th order sound field information in the expected direction;

[0063] Figure 3 Fig. 2 (b) is a comparative schematic diagram of the sound field information of the 1st order in the desired direction;

[0064] Figure 3 Fig. 2 (c) is a comparative schematic diagram of the sound field information of the 2nd order in the desired direction;

[0065] Figure 3 Fig. 2 (d) is a comparative schematic diagram of the sound field information of the 3rd order in the desired direction;

[0066] Figure 3 Fig. 2 (e) is a comparative schematic diagram of the sound field information of the 5th order in the desired direction;

[0067] Figure 4 Fig. 3 (a) is a response diagram of the maximum output of the sound field information of the 0th order in different directions;

[0068] Figure 4 Fig. 3 (b) is a response diagram of the maximum output of the sound field information of the 1st order in different directions;

[0069] Figure 4 Fig. 3 (c) is a response diagram of the maximum output of the sound field information of the 2nd order in different directions;

[0070] Figure 4 Fig. 3 (d) is a response diagram of the maximum output of the sound field information of the 3rd order in different directions;

[0071] Figure 4 Fig. 3 (e) is a response diagram of the maximum output of the sound field information of the 4th order in different directions;

[0072] Figure 5 Fig. 4 (a) is a comparative schematic diagram of the synthesized beam determined by the characteristic beam of the 0th order;

[0073] Figure 5 Fig. 4 (b) is a comparative schematic diagram of the synthesized beam determined by the characteristic beam of the 0th and 1st orders;

[0074] Figure 5 Fig. 4 (c) is a comparative schematic diagram of the synthesized beam determined by the characteristic beam of the 0th-2nd orders;

[0075] Figure 5 Fig. 4 (d) is a comparative schematic diagram of the synthesized beam determined by the characteristic beam of the 0th-3rd orders;

[0076] Figure 5 Fig. 4 (e) is a comparative schematic diagram of the synthesized beam determined by the characteristic beam of the 0th-4th orders. DETAILED DESCRIPTION

[0077] In order to make the above objectives, characteristics and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms, and should not be interpreted as being limited to the embodiments set forth herein, but rather, these embodiments are provided so as to more thoroughly and completely understand the present application. It should be understood that the drawings and embodiments of the present application are merely for illustrative purposes, and are not intended to limit the scope of protection of the present application.

[0078] It should be understood that each of the steps recited in the method embodiments of the present application can be performed in different orders, and / or in parallel. In addition, the method embodiments can include additional steps and / or omit the steps shown. The scope of the present application is not limited in this respect.

[0079] The term "comprising" and variations thereof as used herein are open-ended, that is "including, but not limited to"; the term "based on" is "based, at least in part, on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optional" means "optional in at least some embodiments". Related definitions are given throughout the description. It should be noted that the concepts mentioned in the present application using "first", "second", etc. are merely used to distinguish different devices, modules or units, and are not intended to limit the order or interdependence of the functions performed by these devices, modules or units.

[0080] It should be noted that the modification of "one" or "multiple" mentioned in the present application is illustrative rather than limiting, and those skilled in the art should understand that, unless otherwise explicitly indicated in the context, it should be understood as "one or more".

[0081] The names of the messages or information exchanged between the devices in the embodiments of the present application are merely for illustrative purposes, and are not intended to limit the scope of the messages or information.

[0082] The uniform circular annular acoustic pressure sensor array realizes directional detection, positioning and analysis of spatial acoustic waves by utilizing the propagation characteristics of acoustic waves and the geometric symmetry of the array, and is an important structure in the field of acoustic detection that takes into account omnidirectionality and flexibility.

[0083] As Figure 1As shown in FIG. 1, the uniform circular annular acoustic pressure sensor array includes M array elements, which are array element 0 to array element M-1 respectively. M is an even number, each array element is an acoustic pressure sensor, and each acoustic pressure sensor is a non-directional acoustic pressure sensor. The uniform circular annular acoustic pressure sensor array is placed in the x-o-y plane, the center of the circle is at the coordinate origin, the M array elements are arranged in a circular ring, and the central angles between adjacent two array elements are the same, and the array element 0 and the array element M / 2 are located on the X axis.

[0084] As shown in FIG. 1, the uniform circular annular acoustic pressure sensor array includes M array elements, which are array element 0 to array element M-1 respectively. M is an even number, each array element is an acoustic pressure sensor, and each acoustic pressure sensor is a non-directional acoustic pressure sensor. The uniform circular annular acoustic pressure sensor array is placed in the x-o-y plane, the center of the circle is at the coordinate origin, the M array elements are arranged in a circular ring, and the central angles between adjacent two array elements are the same, and the array element 0 and the array element M / 2 are located on the X axis. Figure 1 As shown in FIG. 1, the uniform circular annular acoustic pressure sensor array includes M array elements, which are array element 0 to array element M-1 respectively. M is an even number, each array element is an acoustic pressure sensor, and each acoustic pressure sensor is a non-directional acoustic pressure sensor. The uniform circular annular acoustic pressure sensor array is placed in the x-o-y plane, the center of the circle is at the coordinate origin, the M array elements are arranged in a circular ring, and the central angles between adjacent two array elements are the same, and the array element 0 and the array element M / 2 are located on the X axis. It should be noted that the axis symmetry in the following refers to the symmetry based on the X axis. The uniform circular annular acoustic pressure sensor array is also a central symmetric structure, that is, the array element m and the array element M / 2+m are central symmetric, . The central angle between adjacent two array elements is The calculation formula is .

[0085] In the related art, based on the uniform circular annular acoustic pressure sensor array, the process of determining the high-order sound field information and the synthesized beam using the characteristic beam decomposition and synthesis theory can be as follows:

[0086] The process of determining the high-order sound field information can be:

[0087] According to the initial characteristic vector of the s-th order and the signals received by each array element in the uniform circular annular acoustic pressure sensor array at the first time, the s-th order sound field information is determined, and all orders of sound field information are taken as high-order sound field information.

[0088] Wherein, , the initial characteristic vector of the s-th order includes characteristic coefficients corresponding to the M array elements, and each characteristic coefficient is used to indicate the weight of the signal of the corresponding array element at the s-th order.

[0089] Specifically, the s-th order sound field information can be determined by the following formula :

[0090] (1)

[0091] Wherein, θ and are the vertical pitch angle and horizontal azimuth angle of the incident signal at the first time respectively, is the initial characteristic vector of the s-th order, indicates the conjugate transpose, indicates the signals received by each array element in the uniform circular annular acoustic pressure sensor array at the first time, and t is the first time.

[0092] Specifically, the initial eigenvector of the s-th order Can be as follows:

[0093] (2)

[0094] Wherein, is The characteristic coefficient corresponding to the array element m, , is the horizontal azimuth angle of the array element m, , Indicates transposition, is the imaginary unit.

[0095] Next, the principle of determining the initial eigenvector of the s-th order is described.

[0096] For a uniform circular ring-shaped acoustic pressure sensor array, the noise received is mainly from the ambient noise. For any two array elements in the uniform circular ring-shaped acoustic pressure sensor array, when the distance between any two array elements is small enough compared with the wavelength (i.e. ), the noise received by the uniform circular ring-shaped acoustic pressure sensor array has certain correlation, so understanding the spatial correlation of the ambient noise plays a very important role in improving the performance of the uniform circular ring-shaped acoustic pressure sensor array.

[0097] Generally, noise can be regarded as a random process, so the noise model is a concept in the statistical sense. In this way, the ambient noise received by each array element in the uniform circular ring-shaped acoustic pressure sensor array Can be written as an M × 1 vector:

[0098] (3)

[0099] Wherein, is the ambient noise received by the array element m.

[0100] Based on this, the noise correlation matrix received by the uniform circular ring-shaped acoustic pressure sensor array Can be expressed as:

[0101] (4)

[0102] Wherein, Indicates mathematical expectation.

[0103] Define the noise cross-spectral matrix as , then the noise correlation matrix Can be re-expressed as:

[0104] (5)

[0105] wherein, , is the noise power spectrum, is the frequency domain noise signal.

[0106] It should be noted that the normalized noise correlation matrix is the noise cross-spectrum matrix .

[0107] Since the spatially isotropic homogeneous noise field, the spectral density distribution is independent of direction, that is, the waves from all directions of space have the same power. Therefore, considering the case that the uniform circular ring-shaped acoustic pressure sensor array is located in the isotropic homogeneous noise field, at this time the noise cross-spectrum matrix can be expressed as:

[0108] (6)

[0109] wherein, the element in , is the noise correlation between the array element m and the array element , , , .

[0110] Since is a circulant matrix, therefore, there is , U is composed of all the eigenvectors of , is the eigenvalue diagonal matrix of , the eigenvalue in corresponds to the eigenvector in U one by one. The eigenvalue size can indicate the noise energy intensity in the corresponding eigenvector direction, and the specific expressions of U and can be as follows:

[0111] (7)

[0112] wherein, is the initial eigenvector of the s-th order, , .

[0113] (8)

[0114] wherein, is the initial eigenvalue corresponding to , .

[0115] It should be noted that in order to facilitate the distinction with the following, the eigenvector is referred to as the initial eigenvector, and the eigenvalue is referred to as the initial eigenvalue.

[0116] It should be noted that since the processing manner of the uniform circular annular sound pressure sensor array to the noise is the same as the processing manner to 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 s-th order is obtained and the initial eigenvalue .

[0117] Indicates the signal received by each element in the uniform circular annular sound pressure sensor array at the first time. Can be expressed as:

[0118] (9)

[0119] Wherein, is an initial response matrix, is the incident signal at the first time, and t is the first time.

[0120] The initial response matrix may include a response component corresponding to each of the M elements, and each response component is used to indicate the deviation of the gain and phase of the corresponding element to the signal of the first incident direction, and the first incident direction is the direction of the incident signal at the first time.

[0121] Specifically, the initial response matrix may be as follows:

[0122] (10)

[0123] Wherein, is the response component corresponding to the element m, is used to indicate the deviation of the gain and phase of the element m to the signal of the first incident direction, , k is the wave number, is the unit vector of the propagation direction of the incident signal at the first time, is the coordinate of the element m in the rectangular coordinate system, is an imaginary unit.

[0124] Based on Figure 1 , the coordinate of each element m in the rectangular coordinate system is as follows:

[0125] (11)

[0126] Wherein, is the vertical pitch angle of the element m, the azimuth angle of the array element m, , denotes the transpose, r is the straight-line distance between the array element m and the origin of the coordinate axis, i.e., the radius of the uniform circular ring-shaped acoustic pressure sensor array.

[0127] It should be noted that, in the coordinate system, Figure 1 , is 90°.

[0128] In the first time, Figure 1 the incident signal at the first time is incident to the uniform circular ring-shaped acoustic pressure sensor array from the direction , the unit vector of the propagation direction of the incident signal at the first time is:

[0129] (12)

[0130] wherein, θ and are the vertical elevation angle and the azimuth angle of the incident signal at the first time , respectively.

[0131] It should be noted that, the negative sign in the expression of is due to the fact that the propagation direction of the incident signal at the first time is opposite to the direction of the signal source relative to the array.

[0132] Next, the process of obtaining the initial response matrix will be described.

[0133] For example, if the incident signal at the first time received at the origin is , the signal received by the array element m at the first time may be:

[0134] (13)

[0135] wherein, , is the imaginary unit, is the frequency of the incident signal at the first time , , is the propagation speed of the sound wave, and λ is the wavelength of the incident signal at the first time , denotes the natural directivity of the array element m, is the time delay of the incident signal at the first time relative to the reference point when it reaches the array element m, .

[0136] Since is the wave number and , , Therefore, formula (13) can be converted into formula (14):

[0137] (14)

[0138] Since the sound pressure sensor is a non-directional sound pressure sensor, the signal received by each array element at the first time On this basis, combined with formula (14), the signal received by each array element at the first time can be expressed as:

[0139] (15)

[0140] wherein , that is .

[0141] It should be noted that, in combination with the foregoing, the response component corresponding to the array element m in the initial response matrix is the product of the incident signal at the first time . .

[0142] Based on this, combined with formula (2), formula (9) and formula (10), formula (1) can be expressed as:

[0143] (16)

[0144] Obviously, since the initial response matrix , the initial eigenvector of the s-th order and the incident signal at the first time are all complex numbers, there are a large number of complex number operations in the process of calculating the s-th order sound field information by formula (16), and complex operations such as multiplication are involved, resulting in high occupation of computing resources, long operation time, and thus reducing the efficiency of determining the s-th order sound field information, and further reducing the efficiency of determining the high-order sound field information.

[0145] In addition, in the process of determining the synthesized beam, the initial eigenvalue corresponding to each order of the initial eigenvector, the expected direction and the initial eigenvalue are needed. Since the initial eigenvalue corresponding to each order of the initial eigenvector is a complex number, and there are a large number of complex number operations in the process of determining each order of the sound field information, there are also a large number of complex number operations in the process of determining the synthesized beam, resulting in high occupation of computing resources, long operation time, and thus reducing the efficiency of determining the synthesized beam.

[0146] To solve the above technical problems, the embodiment of the present application provides a high-order sound field information extraction and beam forming method based on real number weighting processing. The method can reduce complex number operation, thereby reducing the occupation of computing resources and operation time consumption, improving operation efficiency, and further improving the efficiency of high-order sound field information extraction and beam synthesis. The method can be executed by an electronic device, including but not limited to a desktop computer, a notebook computer, an electronic reader, and other electronic devices with data processing capability.

[0147] Before the high-order sound field information extraction and beam forming method based on real number weighting processing provided by the embodiment of the present application is specifically described, the setting principle of the embodiment of the present application is first described, which provides a bottom logic basis for the construction and implementation of subsequent schemes.

[0148] First, the formula (16) is further expanded:

[0149] (17)

[0150] wherein, is the conjugate of .

[0151] Obviously, the sound field information of the s-th order is the conjugate transpose of the linear combination of the initial characteristic vector of the s-th order and the signal received by each element of the uniform circular ring pressure sensor array at the first time.

[0152] The linear combination can be understood as the superposition of the sound field information of the s-th order of M elements, wherein the sound field information of the s-th order of element m can be expressed as: . That is, the sound field information of the s-th order of element m is the product of the conjugate of the characteristic coefficient corresponding to element m in the initial characteristic vector of the s-th order and the signal received by element m at the first time.

[0153] In the summation process of formula (17), for the axisymmetric two elements, i.e., element m and element M-m, , the sum of the sound field information of the s-th order of the axisymmetric two elements can be expressed as:

[0154] (18)

[0155] Substitute into formula (18), and expand formula (18) by using Euler formula .

[0156] (19)

[0157] Based on formula It can be seen that:

[0158] (20)

[0159] (21)

[0160] (22)

[0161] (23)

[0162] Next, according to , , , simplifying and , the simplification process can be as follows:

[0163] (24)

[0164] (25)

[0165] Obviously, , .

[0166] Thus, the sum of the sound field information of the two axisymmetric elements at the s-th order can be transformed as follows:

[0167] (26)

[0168] Since the signals received by the two axisymmetric elements at the first time are similar, the difference between the signals received by the two axisymmetric elements at the first time is small, and the difference is much smaller than the sum of the signals received by the two axisymmetric elements at the first time. Thus, in the above summation process, the imaginary part of the difference between the signals received by the two axisymmetric elements at the first time can be ignored to omit the imaginary number on the basis of ensuring the accuracy of the calculation, thereby reducing the complex number operation.

[0169] Thus, the sum of the sound field information of the two axisymmetric elements at the s-th order can be represented as:

[0170] (27)

[0171] In the summation process of formula (17), for element 0, since element 0 is located on the X-axis, , , the sound field information of element 0 at the s-th order may be:

[0172] (28)

[0173] Obviously, since the imaginary part of the characteristic coefficients corresponding to array element 0 is 0, the imaginary part of the characteristic coefficients corresponding to array element 0 can be omitted. Thus, when calculating the sound field information of array element 0 at the s-th order... During the process, the imaginary part of the characteristic coefficients corresponding to array element 0 can be omitted, thereby reducing complex number operations.

[0174] 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 s-th order Possible forms:

[0175] (29)

[0176] Obviously, since the imaginary part of the characteristic coefficients corresponding to array element M / 2 is 0, the imaginary part of the characteristic coefficients corresponding to array element M / 2 can be omitted. Thus, when determining the sound field information of array element M / 2 at order s... During the process, the imaginary part of the characteristic coefficients corresponding to the array element M / 2 can be omitted, thereby reducing complex number operations.

[0177] In summary, from formulas (27) to (29), it can be seen that the characteristic coefficients corresponding to array element m are... from Become In other words, during the calculation process, the following can be ignored. The imaginary part of . Thus, this can be achieved by removing the initial eigenvector of order s. The imaginary part of each feature coefficient in the vector is used to obtain the target feature vector of order s. This is done by converting the initial eigenvector of order s from complex to real, thereby enabling the computation process to... Replace with This reduces the complexity of complex number operations.

[0178] Wherein, the target feature vector of order s It can be represented as:

[0179] (30)

[0180] in, .

[0181] Next, substituting formula (30) into formula (1) yields:

[0182] (31)

[0183] Will Substituting into formula (31), we get:

[0184] (32)

[0185] Since and is 90°, thus, . And since thus, can be transformed into , the transformation process can be shown as follows:

[0186] (33)

[0187] Since (i.e. cosine difference angle formula), thus, can be expressed as: .

[0188] Thus, according to and Euler formula, formula (32) can be transformed as follows:

[0189] (34)

[0190] In the summation process of formula (34), for the two center-symmetric array elements, i.e. array element m and array element M / 2+m, the sum of the sound field information of the two center-symmetric array elements at the s-th order can be expressed as:

[0191] (35)

[0192] Based on the above, it can be known that:

[0193] ,

[0194] From the above two formulas, it can be known that , thus, the relationship of the horizontal azimuth angles of the two center-symmetric array elements is substituted into the above formula (35) to obtain formula (36):

[0195] (36)

[0196] Since , thus, formula (36) can be simplified as:

[0197] (37)

[0198] In the case of s being even, , thus, formula (37) can be simplified as:

[0199] (38)

[0200] Since and in the case of s being even, Therefore, formula (38) can be transformed as:

[0201] (39)

[0202] Since Therefore, formula (39) can be expressed as:

[0203] (40)

[0204] Obviously, in the case of s being even, in the process of calculating the sum of the sound field information of the two array elements which are central symmetric at the s-th order, the imaginary parts in the response components corresponding to the two array elements cancel each other. That is, the response component corresponding to the array element m is changed to . Thus, by removing the imaginary part of each response component in the initial response matrix , the even-order response matrix can be obtained, where is , so as to convert the initial response matrix into a real number in the case of s being even, so that in the calculation process, by replacing with , the complex operation is reduced on the basis of ensuring the accuracy of the calculation.

[0205] In the case of s being odd, and since , formula (37) can be simplified as:

[0206] (41)

[0207] Since in the case of s being odd, , , the following can be obtained:

[0208] (42)

[0209] In this way, formula (41) can be converted into formula (42) by formula (42):

[0210] (43)

[0211] Since , formula (43) can be transformed as:

[0212] (44)

[0213] ​Since the sound field information of the s-th order is used to indicate the signal receiving response in the full direction, and the signal receiving response is associated with the signal output amplitude in the full direction, and in the formula (44), the imaginary unit indicating the direction is irrelevant to the amplitude, thus, the imaginary unit can be omitted. In this way, the formula (44) can be expressed as:

[0214] (45)

[0215] Obviously, since the sound field information of the s-th order is used to indicate the signal receiving response in the full direction, and the signal receiving response is associated with the signal output amplitude in the full direction, and the imaginary unit indicating the direction is irrelevant to the amplitude, thus, removing the imaginary unit will not affect the accuracy of the calculation result.

[0216] Based on this, in the case of s being an odd number, in the process of calculating the sum of the sound field information of the s-th order of the two center-symmetric array elements, the real parts in the response components corresponding to the two center-symmetric array elements cancel each other out, and the imaginary unit in the imaginary parts in the response components corresponding to the two center-symmetric array elements can be removed. That is, the response component corresponding to the array element m becomes . In this way, the odd-order response matrix can be obtained by removing the real part and the imaginary unit in each response component in the initial response matrix , where is , so as to convert the initial response matrix into a real number in the case of s being an odd number, so that in the calculation process, the is replaced by , so as to reduce the complex number operation on the basis of ensuring the accuracy of the calculation.

[0217] Based on the above, the even-order response matrix can be expressed as:

[0218] (46)

[0219] The odd-order response matrix can be expressed as:

[0220] (47)

[0221] Based on the above description, in order to reduce the complex number operation on the basis of ensuring the accuracy of the calculation, the s-th order target characteristic vector ​, the incident signal at the first time and the even-order response matrix or the odd-order response matrix determine the s-th order sound field information.

[0222] Specifically, in the case of s being even, the s-th order sound field information may be determined by the following formula:

[0223] (48)

[0224] wherein, , In the case of s being even, the signal received by each element in the uniform circular annular booster sensor array at the first time.

[0225] Specifically, in the case of s being odd, the s-th order sound field information may be determined by the following formula:

[0226] (49)

[0227] wherein, , In the case of s being odd, the signal received by each element in the uniform circular annular booster sensor array at the first time.

[0228] In addition, the formula (48) and the formula (49) can also be further simplified by the Jacobi-Anger expansion to further reduce the calculation amount, thereby improving the calculation efficiency and further improving the extraction efficiency of the sound field information. The Jacobi-Anger expansion includes:

[0229] (50)

[0230] (51)

[0231] Specifically, the simplification process of the formula (48) can be as follows:

[0232] By expanding the formula (50) in the formula (48) , the expansion process can be as follows:

[0233] (52)

[0234] wherein, is the n-th order first kind cylindrical Bessel function.

[0235] Since is independent of m, therefore, In advance, formula (52) becomes formula (53):

[0236] (53)

[0237] Since , formula (53) is transformed as follows:

[0238] (54)

[0239] Since , , formula (54) is transformed as follows:

[0240] (55)

[0241] Since and take any value, both and where is a constant. Therefore, formula (55) can be transformed as:

[0242] (56)

[0243] Since when s is not 0, where is a constant.

[0244] Thus, since is a constant, when s is not 0, . Thus, formula (56) can be simplified as:

[0245] (57)

[0246] Continuing to use the principle that when s is not 0, must be an integer greater than 0, . In this way, formula (57) can be simplified as:

[0247] (58)

[0248] Continuing to use the principle that when s is not 0, only when , , when , , Thus, in the case where s is a non-zero even number and , the result of the calculation of equation (58) is 0. In the case where s is a non-zero even number and , equation (58) is valid (i.e., equation (58) works).

[0249] Thus, in the case where s is a non-zero even number, substituting into equation (58) can transform equation (58) into equation (59):

[0250] (59)

[0251] where is the s-th order cylindrical Bessel function of the first kind.

[0252] Obviously, in the case where s is a non-zero even number, the s-th order sound field information can be expressed as:

[0253] (60)

[0254] Since the sound field information is used to indicate the omnidirectional signal receiving response, and the signal receiving response is associated with the omnidirectional signal output amplitude, and indicates the direction, which is irrelevant to the amplitude, thus, removing will not affect the accuracy of the calculation result. Thus, in the case where s is a non-zero even number, the s-th order sound field information can be expressed as:

[0255] (61)

[0256] Since in the case where s is 0, , and in the case where s is 0, , and , thus, , , in the case where s is 0, equation (56) can be transformed as:

[0257] (62)

[0258] Obviously, in the case where s is 0, the s-th order sound field information can be expressed as:

[0259] (63)

[0260] Since in the case where s is 0, , thus, in the case where s is 0, by replacing 0 in equation (63) with s, and adding The sound field information of the sth order when s is 0. Transformed into:

[0261] (64)

[0262] The simplification process of formula (49) can be shown below:

[0263] Using formula (51) to modify formula (49) The expansion process can be performed as follows:

[0264] (65)

[0265] in, It is an nth-order first-class cylindrical Bessel function.

[0266] because It is independent of m, therefore, it can be First, formula (65) is transformed into formula (66):

[0267] (66)

[0268] because Therefore, the following transformation is made to formula (66):

[0269] (67)

[0270] because , Therefore, the following transformation is made to formula (67):

[0271] (68)

[0272] Utilizing and For any value, we have and Based on the principle, formula (68) is simplified to formula (69):

[0273] (69)

[0274] Continue to utilize the condition that s is not 0. ,in, The principle of constants applies. Since n is a positive integer and s is an odd number, therefore, ,so, Thus, formula (69) can be simplified to formula (70):

[0275] (70)

[0276] continuing to use the principle that s is not equal to 0, s is equal to 0, wherein, is a constant. Since s is equal to 0, s is equal to 0, thus, s is equal to 0, s is equal to 0, thus, s is equal to 0, s is equal to 0,

[0277] Thus, in the case that s is an odd number, substituting into formula (70) can transform formula (70) into formula (71):

[0278] (71)

[0279] Since the sound field information is used to indicate the signal receiving response in all directions, and the signal receiving response is associated with the signal output amplitude in all directions, and indicates the direction, and is irrelevant to the amplitude, thus, removing will not affect the accuracy of the calculation result. Thus, in the case that s is an odd number, the sound field information of the s-th order can be expressed as:

[0280] (72)

[0281] In summary, according to formula (61), (64) and (72), it can be known that the calculation formula of the sound field information of the s-th order is the same under different values of s. Thus, through the Jacobi-Anger expansion, the calculation formula of the sound field information of the s-th order can be simplified from formula (48) and formula (49) to formula (73), and formula (73) is as follows:

[0282] (73)

[0283] wherein, here .

[0284] Obviously, through formula (73) to determine the sound field information of the s-th order, the operation amount and the occupation of the calculation resource can be reduced, and the efficiency of determining the sound field information of the s-th order is further improved, and the accuracy of the calculation result is ensured in the simplification process.

[0285] After the calculation formula of the sound field information of the s-th order is determined, the determination of the characteristic beam of the s-th order is described below.

[0286] The characteristic beam of the s-th order The sound field information of the s-th order in the desired direction can be calculated by the following formula:

[0287] (74)

[0288] wherein, is a parameter ensuring that the response of the beam pointing direction is 1, is the initial eigenvalue corresponding to the initial eigenvector of the s-th order, , is the desired direction. It should be noted that the initial eigenvalue corresponding to the initial eigenvector of the s-th order is the initial eigenvalue corresponding to the target eigenvector of the s-th order.

[0289] It should be noted that in the case of calculating the sound field information of the s-th order by formula (73), , is the desired direction.

[0290] In the case of calculating the sound field information of the even order by formula (48):

[0291] wherein s is an even number.

[0292] In the case of calculating the sound field information of the odd order by formula (49):

[0293] wherein s is an odd number.

[0294] is the sound field information of the s-th order in the desired direction, is the sound field information of the M-s-th order in the desired direction. The calculation principle of is the same as that of, which will not be described here.

[0295] On this basis, the calculation formula of is expanded by Euler formula, and the expansion process can be shown as follows:

[0296] (75)

[0297] In the above summation process, for the axisymmetric two elements, i.e. element m and element M-m, the summation formula can be expressed as:

[0298] (76)

[0299] wherein, .

[0300] Since , , ​​Therefore, the following transformation can be made to equation (76):

[0301] (77)

[0302] Since the noise cross-spectral matrix is a circulant matrix, in the case where a takes the value , the following transformation can be made to equation (77):

[0303] (78)

[0304] Since , the following transformation can be made to equation (78):

[0305] (79)

[0306] Obviously, in the summation process of equation (75), the imaginary parts of the two elements symmetric about the axis cancel each other out, so the imaginary part of can be removed.

[0307] In the case where m and a take the value 0, so in the case where m and a take the value 0, the calculation of can be shown as follows:

[0308] (80)

[0309] Obviously, in the case where m and a take the value 0, since , the imaginary part of is also zero, so the imaginary part of can be removed.

[0310] In the case where m and a take the value , so in the case where m and a take the value , the calculation of

[0311] can be shown as follows: (81)

[0312] Obviously, in the case where m and a take the value , so the imaginary part of is also zero, so the imaginary part of can be removed.

[0313] In summary, based on formulas (78), (80), and (81), formula (75) can be simplified to:

[0314] (82)

[0315] in, .

[0316] Obviously, the above principles can be used to... From the complex form Transform into real number form Furthermore, as can be seen from the above, this transformation process will not affect the accuracy of the calculation.

[0317] In this way, it can be removed The imaginary part of the number is obtained. ,in, , Let be the target feature value corresponding to the target feature vector of order s.

[0318] Thus, in calculating the s-th order characteristic beam In the process, by Replace with This reduces complex number operations, improves computational efficiency, and thus improves the efficiency of determining the s-th order characteristic beam.

[0319] Specifically, the s-th order characteristic beam It can be calculated using the following formula:

[0320] (83)

[0321] Furthermore, due to ,therefore, Therefore, we can obtain Therefore, combining the above formulas, we can see that... , .

[0322] Furthermore, ,therefore, .

[0323] In summary, due to , , Therefore, formula (83) can be transformed into:

[0324] (84)

[0325] in, .

[0326] Apparently, since the target eigenvector of the s-th order is the same as the target eigenvector of the M-s-th order, and the target eigenvalue corresponding to the target eigenvector of the s-th order is the same as the target eigenvalue corresponding to the target eigenvector of the M-s-th order, formula (83) can be simplified to formula (84). In this way, the efficiency of determining the eigenbeam of the s-th order can be improved by formula (84).

[0327] The formula for determining the synthetic beam is:

[0328] (85)

[0329] wherein s is 0 at least one of the values, is a synthetic beam, is the eigenbeam of the s-th order.

[0330] Based on the above description, as Figure 2 indicated, the method provided by the embodiments of the present application can include:

[0331] 201. Determining the s-th order sound field information based on the target eigenvector of the s-th order and the signals received by each element of the uniform circular ring-shaped pressure sensor array at the first time, and taking all orders of sound field information as high-order sound field information;

[0332] wherein , the uniform circular ring-shaped pressure sensor array includes M elements, and M is an even number; the uniform circular ring-shaped pressure sensor array is placed in the x-o-y plane, and the center of the uniform circular ring-shaped pressure sensor array is located at the coordinate origin; element 0 and element M / 2 are located on the X axis;

[0333] 202. For s being 0 or M / 2, determining the eigenbeam of the s-th order based on the s-th order sound field information, the target eigenvalue corresponding to the target eigenvector of the s-th order, and the expected direction;

[0334] 203. For 1≤s≤M / 2-1, determining the eigenbeam of the s-th order based on the s-th order sound field information, the target eigenvalue corresponding to the target eigenvector of the s-th order, the M-s-th order sound field information, the target eigenvalue corresponding to the target eigenvector of the M-s-th order, and the expected direction;

[0335] 204. Determining the synthetic beam based on at least one eigenbeam;

[0336] wherein the target eigenvector of the s-th order is obtained by removing the imaginary part of each eigenvalue in the initial eigenvector of the s-th order;

[0337] The initial eigenvector of the s-th order includes eigenco-efficients corresponding to the M elements, and each eigenco-efficient is used to indicate a weight of a signal of a corresponding element at the s-th order;

[0338] The imaginary part of each eigenco-efficient in the initial eigenvector of the s-th order is obtained by multiplying the imaginary part of the corresponding eigenco-efficient in the initial eigenvector of the s-th order of the two axially symmetric elements in the uniform circular ring acoustic pressure sensor array by a difference between signals received by the two axially symmetric elements at the first time, and the signals received by the two axially symmetric elements at the first time are similar, and the imaginary part of the corresponding eigenco-efficient of the element 0 and the element M / 2 in the initial eigenvector of the s-th order is removed because the element 0 and the element M / 2 are located on the X axis and the corresponding eigenco-efficient of the element 0 and the element M / 2 in the initial eigenvector of the s-th order is zero.

[0339] Obviously, since the target eigenvector of the s-th order is obtained by removing the imaginary part of each eigenco-efficient in the initial eigenvector of the s-th order, that is, the target eigenvector of the s-th order is a real number. Therefore, the s-th order sound field information is determined according to the target eigenvector of the s-th order and the signals received by each element in the uniform circular ring acoustic pressure sensor array at the first time, which reduces complex operations, thereby reducing memory occupation and operation time, improving operation efficiency and efficiency of determining the s-th order sound field information. Therefore, since the high-order sound field information is a collection of sound field information of all orders, the efficiency of extracting the high-order sound field information is improved. Based on this, for s being 0 or M / 2, the s-th order characteristic beam is determined according to the s-th order sound field information, the target eigenvalue corresponding to the target eigenvector of the s-th order 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 target eigenvector of the s-th order, the (M-s)-th order sound field information, the target eigenvalue corresponding to the target eigenvector of the (M-s)-th order 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.

[0340] And, since the imaginary part of each eigenvalue in the initial eigenvector of the s-th order is determined in the process that the sound field information of each element in the s-th order is determined according to the eigenvalue corresponding to each element in the initial eigenvector of the s-th order and the signal received by each element at the first time, and the sound field information of all elements in the s-th order is summed to obtain the sound field information of the s-th order, the imaginary part of the eigenvalue corresponding to the two axially symmetric elements in the initial eigenvector of the s-th order is multiplied by the difference between the signals received by the two axially symmetric elements at the first time, and the signals received by the two axially symmetric elements at the first time are similar, and combined with the fact that element 0 and element M / 2 are located on the X-axis, which makes the imaginary part of the eigenvalue corresponding to element 0 and element M / 2 in the initial eigenvector of the s-th order zero and removed. Therefore, by removing the imaginary part of each eigenvalue in the initial eigenvector of the s-th order, the target eigenvector of the s-th order is obtained, which ensures the accuracy of the target eigenvector of the s-th order, and further ensures the accuracy of high-order sound field information extraction and beam synthesis.

[0341] Optionally, the determination of the sound field information of the s-th order according to the target eigenvector of the s-th order and the signal received by each element in the uniform circular ring acoustic pressure sensor array at the first time comprises:

[0342] In a case that s is even, the sound field information of the s-th order is determined according to the target eigenvector of the s-th order, the even-order response matrix and the incident signal at the first time; in a case that s is odd, the sound field information of the s-th order is determined according to the target eigenvector of the s-th order, the odd-order response matrix and the incident signal at the first time; 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 comprises response components corresponding to the M elements one by one, each response component is used to indicate the deviation of the gain and the phase of the corresponding 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 removed based on the fact that the imaginary parts of the corresponding response components of the two elements symmetric to the center in the uniform circular ring-shaped acoustic pressure sensor array cancel each other out in the process of determining the sound field information of each element at the s-th order according to the characteristic coefficients of the elements in the target eigenvector of the s-th order, the response components of the elements in the initial response matrix and the incident signal at the first time, and summing the sound field information of all elements at the s-th order to obtain the sound field information of the s-th order; the real part of each response component in the initial response matrix and the imaginary unit are removed based on the fact that the real parts of the corresponding response components of the two elements symmetric to the center in the uniform circular ring-shaped acoustic pressure sensor array cancel each other out, and the sound field information of the s-th order indicates the signal receiving response in all directions and the signal receiving response is associated with the signal output amplitude in all directions in the process of determining the sound field information of each element at the s-th order according to the characteristic coefficients of the elements in the target eigenvector of the s-th order, the response components of the elements in the initial response matrix and the incident signal at the first time, and summing the sound field information of all elements at the s-th order to obtain the sound field information of the s-th order.

[0343] Optionally, the initial eigenvector of the s-th order is:

[0344]

[0345] wherein, is the initial eigenvector of the s-th order, is is the characteristic coefficient corresponding to the element m in the matrix, , is the horizontal azimuth angle of the element m, indicates transposition, is an imaginary unit, and s is an order number;

[0346] The target eigenvector of the s-th order is:

[0347]

[0348] in, , Let be the target feature vector of order s. for The eigenvalues ​​corresponding to the matrix element m.

[0349] Optionally, the initial response matrix is:

[0350]

[0351] in, The initial response matrix, for The response components corresponding to the array element m. , For wave number, Let be the unit vector representing the propagation direction of the incident signal at the first moment. Let m be the coordinates of the array element m in a rectangular coordinate system. The imaginary unit, Indicate transpose, θ and These are the vertical elevation angle and horizontal azimuth angle of the incident signal at the first moment, respectively;

[0352] The even-order response matrix is:

[0353]

[0354] in, The response matrix is ​​of even order. , for The response components corresponding to the array element m. denoted as the horizontal azimuth angle of array element m, and r is the straight-line distance between array element m and the coordinate axis dots.

[0355] The odd-order response matrix is:

[0356]

[0357] in, For odd-order response matrices, , for The response component corresponding to the middle array element m.

[0358] Optionally, when s is even, determining the sound field information of the s-th order based on the target feature vector of the s-th order, the even-order response matrix, and the incident signal at the first moment includes:

[0359] When s is even, the sound field information of the s-th order is determined by the following formula:

[0360]

[0361] wherein, is the sound field information of the s-th order, is a characteristic coefficient corresponding to the element m in the target eigenvector of the s-th order, is the incident signal at the first time;

[0362] In the case where s is an odd number, the sound field information of the s-th order is determined according to the target eigenvector of the s-th order, the odd-order response matrix and the incident signal at the first time, and the method comprises the following steps of:

[0363] In the case where s is an odd number, the sound field information of the s-th order is determined by the following formula:

[0364] .

[0365] Optionally, the method further comprises:

[0366] The formula for determining the sound field information of the even order and the formula for determining the sound field information of the odd order are transformed into the following formula by means of the Jacobi-Anger expansion:

[0367]

[0368] wherein, is the s-th order first-type cylindrical Bessel function.

[0369] Optionally, in the case where s is 0 or M / 2, the characteristic beam of the s-th order is determined according to the sound field information of the s-th order, the target eigenvalue corresponding to the target eigenvector of the s-th order and the expected direction, and the method comprises the following steps of:

[0370] The characteristic beam of the s-th order is determined by the following formula:

[0371]

[0372] wherein, , is the characteristic beam of the s-th order, is a parameter for ensuring that the response of the beam pointing direction is 1, is the target eigenvalue corresponding to the target eigenvector of the s-th order, is the expected direction, is the sound field information of the s-th order in the expected direction, is the sound field information of the s-th order, and are the vertical elevation angle and the horizontal azimuth angle of the incident signal at the first time, respectively;

[0373] The characteristic beam of the s-th order is determined according to the s-th order sound field information, the target eigenvalue corresponding to the target eigenvector of the s-th order, the M-s-th order sound field information, the target eigenvalue corresponding to the target eigenvector of the M-s-th order, and the expected direction, wherein 1≤s≤M / 2-1.

[0374] The characteristic beam of the s-th order is determined by the following formula:

[0375]

[0376] wherein, , is the characteristic beam of the s-th order, is a parameter for ensuring that the response of the beam pointing direction is 1, is the target eigenvalue corresponding to the target eigenvector of the s-th order, is the expected direction, is the sound field information of the s-th order in the expected direction, is the sound field information of the s-th order, is the target eigenvalue corresponding to the target eigenvector of the M-s-th order, is the sound field information of the M-s-th order in the expected direction, is the sound field information of the M-s-th order, and are the vertical elevation angle and the horizontal azimuth angle of the incident signal at the first time, respectively.

[0377] The target eigenvalue corresponding to the target eigenvector of the s-th order is obtained by removing the imaginary part in the initial eigenvalue corresponding to the target eigenvector of the s-th order.

[0378]

[0379] wherein, is the target eigenvalue corresponding to the target eigenvector of the s-th order, , , is the noise correlation between the array element m and the array element , , , , is the horizontal azimuth angle of the array element m.

[0380]

[0381] wherein, is the initial eigenvalue corresponding to the target eigenvector of the s-th order;

[0382] The imaginary part in the initial eigenvalue corresponding to the target eigenvector of the s-th order is based on m being 0 and is made The imaginary part is 0, and combined with , Two array elements that are axially symmetric The imaginary parts of the sum cancel each other out and are removed.

[0383] Optionally, the method further includes:

[0384] Based on the fact that the target feature vector of order s and the target feature vector of order Ms are the same, and the target feature value corresponding to the target feature vector of order s and the target feature value corresponding to the target feature vector of order Ms are the same, the formula for determining the feature beam of order s is transformed as follows:

[0385]

[0386] in, .

[0387] Optionally, determining the synthesized beam based on at least a first-order characteristic beam includes:

[0388] The synthesized beam is determined using the following formula:

[0389]

[0390] Where s is 0~ At least one of them, For synthesized beams, For the characteristic beam of order s, θ and These are the vertical elevation angle and horizontal azimuth angle of the incident signal at the first moment, respectively.

[0391] It should be noted that the implementation method and principle of the above steps have been explained above, and will not be repeated here.

[0392] The following simulation comparison will be performed between the high-order sound field information extraction and beamforming method of real number weighted processing provided in the embodiments of this application and the sound field information of each order in the desired direction determined by the characteristic beam decomposition and synthesis theory in related technologies, so as to verify the consistency between the high-order sound field information extraction and beamforming method of real number weighted processing provided in the embodiments of this application and the characteristic beam decomposition and synthesis theory in related technologies.

[0393] Simulation results are as follows Figure 3 As shown, Figure 3 (a) is a schematic diagram comparing the sound field information of the 0th order in the desired direction. Figure 3 (b) is a schematic diagram comparing the sound field information of the first order in the desired direction. Figure 3 Image (c) is a schematic diagram comparing the sound field information of the second order in the desired direction. Figure 3Image (d) is a schematic diagram comparing the sound field information of the third order in the desired direction. Figure 3 Figure (e) shows a comparative schematic diagram of the sound field information in the desired direction for the 5th order. 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 500 Hz, and the desired signal direction (i.e., the desired direction) is set as follows: .

[0394] Depend on Figure 3 As can be seen from the embodiments of this application, the sound field information of each order in the desired direction determined by the embodiments of this application, compared with the sound field information of each order in the desired direction determined by the characteristic beam decomposition and synthesis theory in related technologies, satisfies the following conditions: Under the given conditions, the two methods obtain sound field information of each order in the desired direction with good consistency, indicating that the real number weighted processing method for extracting high-order sound field information and beamforming provided in this application embodiment can accurately extract high-order modal sound field information.

[0395] Since the original analog signal acquired in the actual uniform circular sound pressure sensor array receiving system is in real number form, further simulation analysis of the received single-frequency signal is considered. A single-frequency signal with a frequency of 500Hz and a sampling frequency of 16kHz is generated, with the signal incident direction varying from 0° to 360°. Combining the scheme provided in the embodiments of this application, the simulated signal is directly subjected to real-number weighted summation to obtain the sound field information output of each order in different directions. Figure 4 (a) shows the response diagram of the maximum output value of the 0th order sound field information in different directions. Figure 4 (b) shows the response diagram of the maximum output value of the first-order sound field information in different directions. Figure 4 (c) shows the response diagram of the maximum output value of the second-order sound field information in different directions. Figure 4 In the middle (d), the response diagram shows the maximum output value of the third-order sound field information in different directions. Figure 4 Figure (e) shows the response diagram of the maximum output value of the fourth-order sound field information in different directions. It can be found that after the simulated signal is processed by real number weighted summation, its spatial output response in different directions maintains good consistency with the spatial directivity of the sound field information in the theoretical real number form, thus verifying the effectiveness of the embodiments of this application in processing the actual array received signal.

[0396] Based on the comparative simulation of the characteristic beam obtained by real number weighting processing (i.e., the embodiment of this application) and the characteristic beam obtained by the characteristic beam decomposition and synthesis model, a comparative simulation of the synthetic beam obtained by real number weighting processing and the synthetic beam obtained by the existing characteristic beam decomposition and synthesis model is further obtained. Figure 5 (a) is a comparative schematic diagram of the synthesized beam determined by the 0th-order characteristic beam.Figure 5 Fig. 4 is a comparison diagram of the synthetic beam determined by the characteristic beams of the 0th and 1st orders, Figure 5 Fig. 5 is a comparison diagram of the synthetic beam determined by the characteristic beams of the 0th-2nd orders, Figure 5 Fig. 6 is a comparison diagram of the synthetic beam determined by the characteristic beams of the 0th-3rd orders, Figure 5 Fig. 7 is a comparison diagram of the synthetic beam determined by the characteristic beams of the 0th-4th orders. It can be found that the spatial responses of the synthetic beams of the two methods are also in good consistency.

[0397] Here, the calculation costs of the embodiments of the present application and the characteristic beam decomposition and synthesis methods are compared and analyzed. In actual engineering applications, the real part and the imaginary part of a complex number need to be stored, which is equivalent to twice the amount of real data, and the memory occupation in matrix operation is significantly increased. Specifically, complex addition and subtraction operations need to be operated on the real part and the imaginary part respectively, and the calculation amount is twice that of real number operation under the same conditions. Once complex multiplication operation includes 4 real multiplication and 2 addition operations, while real multiplication operation only needs 1 time. Taking the characteristic beam solving as an example, the embodiments of the present application adopt the real number weighting processing mode, which can save the operation process of the complex number part in the weighting coefficient, so the calculation amount of the present application is reduced to half of the original method. Therefore, the embodiments of the present application adopt the real number weighting processing mode, which can greatly reduce the calculation complexity in actual engineering applications and effectively improve the calculation efficiency of the real-time processing system. In actual applications, the embodiments of the present application can realize real-time and accurate acquisition of high-order modal sound field information by reasonably designing a combination of analog addition and subtraction amplifiers, which has the characteristics of being simple and easy to implement, and provides a theoretical basis for the effective use of high-order sound field information in the future.

[0398] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any change or replacement within the technical scope disclosed in the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of real-valued weighted processing high-order sound field information extraction and beamforming, characterized in that, The method comprises the following steps: determining the sound field information of the s-th order according to the target characteristic vector of the s-th order and the signals received by each element in the uniform circular ring-shaped acoustic pressure sensor array at the first time, and taking the sound field information of all orders as high-order sound field information; wherein, The uniform circular annular sound pressure sensor array comprises M elements, and M is an even number; the uniform circular annular sound pressure sensor array is arranged in an x-o-y plane, and the center of the uniform circular annular sound pressure sensor array is located at a coordinate origin; an element 0 and an element M / 2 are located on an X axis. for s being 0 or M / 2, determining the characteristic beam of the s-th order according to the sound field information of the s-th order, the target eigenvalue corresponding to the target characteristic vector of the s-th order and the expected direction; for 1≤s≤M / 2-1, determining the characteristic beam of the s-th order according to the sound field information of the s-th order, the target eigenvalue corresponding to the target characteristic vector of the s-th order, the sound field information of the M-s-th order, the target eigenvalue corresponding to the target characteristic vector of the M-s-th order and the expected direction; determining the synthesized beam according to at least one order of the characteristic beam; wherein the target characteristic vector of the s-th order is obtained by removing the imaginary part of each characteristic coefficient in the initial characteristic vector of the s-th order; the initial characteristic vector of the s-th order comprises characteristic coefficients corresponding to the M elements one by one, and each characteristic coefficient is used to indicate the weight of the signal of the corresponding element at the s-th order; the imaginary part of each characteristic coefficient in the initial characteristic vector of the s-th order is obtained by multiplying the imaginary part of the corresponding characteristic coefficient in the initial characteristic vector of the s-th order of the two axially symmetric elements in the uniform circular ring-shaped acoustic pressure sensor array and the difference between the signals received by the two axially symmetric elements at the first time, and the signals received by the two axially symmetric elements at the first time are similar, and the imaginary part of the corresponding characteristic coefficient of the element 0 and the element M / 2 in the initial characteristic vector of the s-th order is removed because the element 0 and the element M / 2 are located on the X axis.

2. The high-order acoustic field information extracting and beamforming method according to claim 1, characterized in that, The method comprises the following steps: in the case that s is an even number, determining the sound field information of the s-th order according to the target characteristic vector of the s-th order, the even-order response matrix and the incident signal at the first time; in the case that s is an odd number, determining the sound field information of the s-th order according to the target characteristic vector of the s-th order, the odd-order response matrix and the incident signal at the first time; 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 comprises response components corresponding to the M elements one by one, and each response component is used to indicate the deviation of the gain and phase of the signal of the corresponding element to 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 removed based on the imaginary parts of the corresponding response components of the two center-symmetric elements in the uniform circular ring-shaped acoustic pressure sensor array in the initial response matrix canceling each other in the process of determining the sound field information of each element at the s-th order according to the corresponding characteristic coefficients of the elements in the target eigenvector of the s-th order, the corresponding response components of the elements in the initial response matrix and the incident signal at the first time, and summing the sound field information of all elements at the s-th order to obtain the sound field information of the s-th order; The real part and the imaginary unit of each response component in the initial response matrix are removed based on the real parts of the corresponding response components of the two center-symmetric elements in the uniform circular ring-shaped acoustic pressure sensor array in the initial response matrix canceling each other, and the sound field information of the s-th order indicating the signal receiving response in all directions and the signal receiving response being associated with the signal output amplitude in all directions in the process of determining the sound field information of each element at the s-th order according to the corresponding characteristic coefficients of the elements in the target eigenvector of the s-th order, the corresponding response components of the elements in the initial response matrix and the incident signal at the first time, and summing the sound field information of all elements at the s-th order to obtain the sound field information of the s-th order.

3. The high-order acoustic field information extracting and beamforming method according to claim 2, characterized in that, The initial eigenvector of the s-th order is: wherein is the initial eigenvector of order s, is is the eigencoefficient corresponding to the array element m in , is the horizontal azimuth angle of the array element m, denotes transposition, is the imaginary unit, s is the order; The target eigenvector of the s-th order is: wherein, , is the target feature vector of order s, is the target feature vector of order s, is the feature coefficient corresponding to the array element m in the matrix.

4. The high-order acoustic field information extracting and beamforming method according to claim 3, characterized in that, The initial response matrix is: wherein, is an initial response matrix, is is a response component corresponding to an array element m, , is a wave number, is a unit vector of a propagation direction of the incident signal at the first time, is a coordinate of the array element m in a rectangular coordinate system, is an imaginary unit, indicates a transpose, and are a vertical elevation angle and a horizontal azimuth angle of the incident signal at the first time, respectively. The even-order response matrix is: wherein, is an even order response matrix, , is a response component corresponding to an array element m, is the horizontal azimuth angle of array element m, and r is the straight-line distance between array element m and the origin of the coordinate axis. The odd-order response matrix is: wherein is an odd order response matrix, , is the response component corresponding to the array element m.

5. The high-order acoustic field information extracting and beamforming method according to claim 4, characterized in that, In the case that s is an even number, the sound field information of the s-th order is determined according to the target eigenvector of the s-th order, the even-order response matrix and the incident signal at the first time, and includes: In the case that s is an even number, the sound field information of the s-th order is determined by the following formula: wherein, is the sound field information of the s-th order, is the feature coefficient corresponding to the m-th element in the target feature vector of the s-th order, is the incident signal at the first time instant; In the case that s is an odd number, the sound field information of the s-th order is determined according to the target eigenvector of the s-th order, the odd-order response matrix and the incident signal at the first time, and includes: In the case that s is an odd number, the sound field information of the s-th order is determined by the following formula: 。 6. The high-order acoustic field information extracting and beamforming method according to claim 5, characterized in that, 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 formula by Jacobian-Angel expansion: wherein is a s-th order first kind cylindrical Bessel function.

7. The high-order acoustic field information extracting and beamforming method according to claim 1, characterized in that, In the case that s is 0 or M / 2, the characteristic beam of the s-th order is determined according to the sound field information of the s-th order, the target eigenvalue corresponding to the target eigenvector of the s-th order and the expected direction, and includes: The characteristic beam of the s-th order is determined by the following formula: wherein, , is the characteristic beam of the s-th order, is a parameter that ensures the response of the beam pointing direction is 1, is the target eigenvalue corresponding to the target eigenvector of the s-th order, is the desired direction, is the sound field information in the desired direction of the s-th order, is the sound field information of the s-th order, and are the vertical elevation angle and the horizontal azimuth angle of the incident signal at the first time, respectively. In the case that 1≤s≤M / 2-1, the characteristic beam of the s-th order is determined according to the sound field information of the s-th order, the target eigenvalue corresponding to the target eigenvector of the s-th order, the sound field information of the M-s-th order, the target eigenvalue corresponding to the target eigenvector of the M-s-th order and the expected direction, and includes: The characteristic beam of the s-th order is determined by the following formula: wherein, , is a characteristic beam of the s-th order, is a parameter to ensure the response of the beam pointing direction is 1, is a target eigenvalue corresponding to the target eigenvector of the s-th order, is a desired direction, is a sound field information in the desired direction of the s-th order, is a sound field information of the s-th order, is a target eigenvalue corresponding to the target eigenvector of the M-s-th order, is a sound field information in the desired direction of the M-s-th order, is a sound field information of the M-s-th order, and are the vertical elevation angle and the horizontal azimuth angle of the incident signal at the first time, respectively. The target eigenvalue corresponding to the target eigenvector of the s-th order is obtained by removing the imaginary part of the initial eigenvalue corresponding to the target eigenvector of the s-th order; wherein, the target eigenvalue corresponding to the target eigenvector of the s-th order, , , the noise correlation between the array element m and the array element , , , , the horizontal azimuth angle of the array element m; wherein, is the initial eigenvalue corresponding to the target eigenvector of the s-th order; The imaginary part of the initial eigenvalue corresponding to the target eigenvector of the s-th order is based on m being 0 and The imaginary part of the initial eigenvalue corresponding to the target eigenvector of the s-th order is based on m being 0 and The imaginary part of the initial eigenvalue corresponding to the target eigenvector of the s-th order is based on m being 0 and The imaginary part of the initial eigenvalue corresponding to the target eigenvector of the s-th order is based on m being 0 and The imaginary part of the initial eigenvalue corresponding to the target eigenvector of the s-th order is based on m being 0 and The imaginary part of the initial eigenvalue corresponding to the target eigenv 8. The high-order acoustic field information extracting and beamforming method according to claim 7, characterized in that, The method further includes: Based on the target eigenvector of the s-th order and the target eigenvector of the M-s-th order being the same and the target eigenvalue corresponding to the target eigenvector of the s-th order and the target eigenvalue corresponding to the target eigenvector of the M-s-th order being the same, the formula for determining the characteristic beam of the s-th order is transformed into: wherein .

9. The high-order acoustic field information extracting and beamforming method according to claim 1, characterized in that, The method further includes determining a composite beam according to the characteristic beam of at least one order, wherein the composite beam is determined by the following formula: The composite beam is determined by the following formula: wherein s is 0 at least one of is a synthetic beam, is an eigenbeam of the s-th order, and are the vertical elevation angle and the horizontal azimuth angle of the incident signal at the first time, respectively.

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