Constant-beam-width beam forming method, system, equipment and medium

Abstract

The invention provides a constant-beam-width beam forming method, system and device and a medium, and relates to the technical field of beam forming, and the constant-beam-width beam forming method comprises the steps: obtaining a receiving signal of a non-uniform symmetric microphone array; performing signal processing based on a time domain and a frequency domain on the received signal to obtain a received signal model; sampling each microphone position in the microphone array to obtain an initial beam former weight; adjusting and normalizing the weight of each initial beam former in the microphone array to obtain the weight of the beam former; and according to the received signal model and the weight of the beam former, an estimated value corresponding to the incident direction of the incident signal source is obtained through output of the constant-beam-width beam former. According to the method, the system, the equipment and the medium provided by the invention, the microphone array can have the same spatial response to the input signals with different frequencies in the main lobe width.

Description

Technical Field

[0001] The present invention relates to the field of beamforming technology, and in particular to a constant beamwidth beamforming method, system, device and medium. Background Art

[0002] Microphone array-based beamforming technology is widely used to enhance signals from a desired direction and suppress noise and interference signals from other directions. Deterministic and adaptive beamforming techniques have been widely studied and applied in radar, sonar, seismology, acoustic imaging, communications, and many other fields. However, the beam width of the beam pattern of traditional beamforming techniques changes with frequency, such as delay-sum beamforming, which limits their application in broadband signals (e.g., voice communications). The basic approach to solve this problem is to design a beamformer with a constant beam width. Constant beamwidth beamforming means that after a broadband signal passes through a specific microphone sensor array, the main lobe width of the beam pattern remains relatively constant within the designed range, so that the broadband beam maintains consistent frequency.

[0003] Most existing beamformers with constant beamwidth are designed based on uniform linear arrays (ULA), but some are designed based on uniform circular arrays (UCA) and arbitrary geometric arrays. In practical applications, since geometric arrays of different shapes will produce different beamformer performances, the constant beamwidth beamforming technology using uniform symmetric linear arrays cannot maintain the required constant beamwidth in a lower frequency range. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a constant beamwidth beamforming method, system, device and medium, which are used to solve the problem in the prior art that different shapes of geometric arrays will produce different beamformer performances, and the constant beamwidth beamforming technology using a uniform symmetric linear array cannot maintain the required constant beamwidth in a lower frequency range.

[0005] To achieve the above-mentioned object and other related objects, the present invention provides a constant beamwidth beamforming method, comprising: acquiring a received signal of a non-uniform symmetrical microphone array; performing signal processing based on time domain and frequency domain on the received signal to obtain a received signal model; sampling at each microphone position in the microphone array to obtain an initial beamformer weight; adjusting and normalizing each initial beamformer weight in the microphone array to obtain a beamformer weight; and obtaining an estimated value corresponding to an incident direction of an incident signal source through a constant beamwidth beamformer output according to the received signal model and the beamformer weight.

[0006] In one embodiment of the present invention, a received signal is subjected to signal processing based on the time domain and the frequency domain to obtain a received signal model, including: processing the received signal in a preset time domain to obtain a time domain received signal; performing a short-time Fourier transform on the time domain received signal to obtain a frequency domain received signal; generating a received signal model in the frequency domain based on the frequency domain received signal; and rearranging the received signal model to obtain a vector form of the received signal model.

[0007] In one embodiment of the present invention, generating a received signal model in the frequency domain according to the received signal in the frequency domain includes:

[0008] Based on a non-uniform symmetric linear array with an odd number of microphones, the positions of the microphones are obtained

[0009] When n = 0, according to the position of the microphone Get the frequency domain representation X0(f) of the incident signal source of interest x0(t) corresponding to the microphone position x0, where -N≤n≤N;

[0010] In the frequency domain received signal at the nth microphone in the non-uniform linear array, the output noisy signal Y represented in the frequency domain in the frequency domain received signal is n (f), expected source signal X n (f), additive noise signal V n (f) and the incident signal source X0(f), generate the corresponding received signal model with time frequency f in the frequency domain:

[0011] Where n is the position index of the microphone, n satisfies 2n+1=M, M is the number of microphones in the non-uniform symmetric linear array; f is the time frequency and f>0; -j is the imaginary unit and there is j 2 =-1; c is the speed of sound; θ s is the incident direction of the source signal, and t is the time in the time domain.

[0012] In one embodiment of the present invention, the received signal model is rearranged to obtain a vector form of the received signal model, including:

[0013] The received signal model Arrange in vector form, and the vector form of the received signal model is y(f)=x(f)+v(f)=d(f,θ s )X0(f)+v(f);

[0014] According to the vector form of the received signal model, y(f)=x(f)+v(f)=d(f,θ s )X0(f)+v(f), and we get the noisy signal vector y(f)=[Y -N(f),…,Y0(f),…,Y N (f)] T , expected source signal vector x(f) = [X -N (f),…,X0(f),…,X N (f)] T , additive noise signal vector v(f) = [V -N (f),…,V0(f),…,V N (f)] T and a steering vector of length 2n+1

[0015] Where T is the permutation operator.

[0016] In one embodiment of the present invention, sampling is performed at each microphone position in the microphone array to obtain initial beamformer weights, including:

[0017] The initial beamformer weights are obtained by sampling different microphone positions in the microphone array through continuous Kaiser windows.

[0018] Among them, x n represents the position of the microphone in the array, and x n Satisfy the formula n is the position index of the microphone, and n satisfies -N≤n≤N; J0 is a first-kind zero-order modified Bessel function; β is a window shape factor, and β represents an adjustable parameter; W is a window support.

[0019] In one embodiment of the present invention, each initial beamformer weight in the microphone array is adjusted and normalized to obtain a beamformer weight, including:

[0020] Using the trapezoidal integration technique, the initial beamformer weights w for the outermost and innermost microphones are k (x n ) are respectively multiplied by the corresponding microphone spacing △n to calculate and adjust to obtain an adjusted intermediate value of the beamformer weight;

[0021] Normalize the middle value of the beamformer weight to get the beamformer weight

[0022] The microphone spacing △n of the outermost microphone satisfies △n=x N -x N-1 , |n|=N, the microphone spacing △n of the outermost microphone satisfies

[0023] In one embodiment of the present invention, according to the received signal model and the beamformer weight, an estimated value corresponding to the incident direction of the incident signal source is obtained through a constant beamwidth beamformer output, including:

[0024] Get the incident direction θ of the incident signal source x0(t) s ;

[0025] According to the incident direction θ of the incident signal source x0(t) s , the output of the constant beamwidth beamformer is as an estimate;

[0026] Where h(f) is the normalized beamformer weight of length 2N+1; * is the complex conjugate operator; H is the conjugate transpose operator; Z(f) is the estimated value of the desired source signal X0(f) in the frequency domain; d(f,θ) is the steering vector of length 2n+1; Y n (f) is the output noisy signal represented in the frequency domain; X0(f) is the desired signal source represented in the frequency domain; y(f) is the noisy signal vector represented in the frequency domain.

[0027] To achieve the above-mentioned purpose and other related purposes, the present invention also provides a constant beamwidth beamforming system, comprising: a receiving module, used to obtain a received signal of a non-uniformly symmetrical microphone array; a processing module, used to perform signal processing based on the time domain and the frequency domain on the received signal to obtain a received signal model; a sampling module, used to sample each microphone position in the microphone array to obtain an initial beamformer weight; an adjustment module, used to adjust and normalize each initial beamformer weight in the microphone array to obtain a beamformer weight; and an output module, used to obtain an estimated value corresponding to the incident direction of an incident signal source through a constant beamwidth beamformer output according to the received signal model and the beamformer weight.

[0028] To achieve the above-mentioned purpose and other related purposes, the present invention further provides an electronic device, which includes: one or more processors; a storage device for storing one or more programs, and when the one or more programs are executed by one or more processors, the electronic device implements the aforementioned constant beamwidth beamforming method.

[0029] To achieve the above objectives and other related objectives, the present invention further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor of a computer, the computer executes the above-mentioned constant beamwidth beamforming method.

[0030] As described above, a constant beamwidth beamforming method, system, device and medium of the present invention have the following beneficial effects: by using trapezoidal integration technology based on a non-uniform symmetric linear array, each beamformer weight is multiplied by the microphone spacing under the non-uniform array, so that at low frequencies, the internal microphone sensors with smaller spacing are invalid due to the smaller weights assigned, and the external sensors with larger spacing are assigned larger weights. Moreover, by utilizing the symmetric properties of the non-uniform linear array, the array has the same spatial response to input signals of different frequencies within the main lobe width, effectively expanding the low-frequency range for maintaining the required constant beamwidth, thereby achieving constant beamwidth at lower frequencies by controlling window parameters (window shape factor), that is, achieving constant beamwidth within a larger frequency range and improving directivity at low frequencies. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic flow chart of a constant beamwidth beamforming method provided by an embodiment of the present invention.

[0032] Figure 2 A diagram showing the position of a non-uniform symmetric linear array used in accordance with an embodiment of the present invention.

[0033] Figure 3 It shows a constant beam width beam pattern based on a uniform symmetric line array method in the prior art.

[0034] Figure 4 Shown is a constant beamwidth beam pattern based on a non-uniform symmetric microphone array method provided by an embodiment of the present invention.

[0035] Figure 5 Shown is a comparison diagram of the constant beam width frequency ranges of a non-uniform symmetric microphone array method and a uniform symmetric linear array method provided by an embodiment of the present invention.

[0036] Figure 6 Shown is a comparison chart of directivity indexes of a microphone array method based on a non-uniform symmetry and a microphone array method based on a uniform symmetric line array provided in one embodiment of the present invention.

[0037] Figure 7 Shown is a structural block diagram of a constant beamwidth beamforming system provided by an embodiment of the present invention.

[0038] Figure 8 Shown is a structural schematic diagram of an electronic device according to an embodiment of the present invention.

[0039] Component number description

[0040] Electronic device 1; constant beamwidth beamforming system 11; memory 12; processor 13; receiving module 111; processing module 112; sampling module 113; adjustment module 114; output module 115. DETAILED DESCRIPTION

[0041] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0042] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0043] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0044] See also Figure 1 The present invention provides a constant beamwidth beamforming method, comprising:

[0045] Step S10: obtaining a received signal of the non-uniform symmetric microphone array;

[0046] Step S20: performing signal processing based on the time domain and the frequency domain on the received signal to obtain a received signal model;

[0047] Step S30: sampling each microphone position in the microphone array to obtain an initial beamformer weight;

[0048] Step S40: adjusting and normalizing each initial beamformer weight in the microphone array to obtain a beamformer weight;

[0049] Step S50: according to the received signal model and the beamformer weights, an estimated value corresponding to the incident direction of the incident signal source is obtained through the constant beamwidth beamformer output.

[0050] Through the above steps, it is not difficult to find that in order to obtain a constant beam width, according to the symmetric property of the non-uniform linear array, the received signal of the non-uniform symmetric microphone array is obtained, and then the received signal is processed in the time domain and frequency domain to obtain the frequency domain received signal, and then the received signal model is generated according to the frequency domain received signal. Because some microphones in the symmetric linear array are closely spaced, the initial beamformer weights can be obtained by sampling at each microphone position in the microphone array, and then the initial beamformer weights are adjusted so that the required constant beam width can still be maintained at low frequencies, and then normalized to obtain the final constant beam width beamformer weights to reduce the influence of the central sensors close together on the formation of the constant beam width. Finally, according to the obtained received signal model and beamformer weights, the estimated value corresponding to the incident direction of the incident signal source is calculated by the constant beam width beamformer. The above method can make the internal microphone sensors with smaller spacing become ineffective at low frequencies due to the smaller weights assigned to them, while the external sensors with larger spacing are assigned larger weights, effectively expanding the low-frequency range for maintaining the required constant beam width, and achieving a constant beam width at lower frequencies.

[0051] Figure 1 A flowchart of a constant beam width beam forming method in an exemplary embodiment of the present application is shown, including steps S10 to S60. Figure 1 The technical solution of this application will be described in detail.

[0052] First, step S10 is performed to obtain a received signal of the non-uniform symmetric microphone array.

[0053] When acquiring the received signal, the received signal corresponds to the position of each microphone in the non-uniform symmetric microphone array. In the present invention, the non-uniform symmetric linear array is an odd number of microphones, and the number of microphones in the array satisfies M=2n+1. Moreover, since the microphones adopt a symmetrical array, the phase center of the array is frequency-invariant, so the position of the microphone can be expressed as In the formula, x n is the position of the microphone, n is the position index of the microphone, and since the microphone array is symmetrical, the range of n is constrained to -N≤n≤N.

[0054] Next, step S20 is executed to perform signal processing based on the time domain and the frequency domain on the received signal to obtain a received signal model.

[0055] After obtaining the received signal of the non-uniform symmetrical microphone array, it is necessary to further convert the received signal in the time domain and the frequency domain to obtain a received signal model for calculating the estimated value of the constant beamwidth beamformer output.

[0056] In step S20, the received signal is subjected to signal processing based on the time domain and the frequency domain to obtain a received signal model, including:

[0057] Step S201: Processing a received signal in a preset time domain to obtain a time domain received signal;

[0058] Step S202: performing short-time Fourier transform on the time domain received signal to obtain a frequency domain received signal;

[0059] Step S203: generating a received signal model in the frequency domain according to the received signal in the frequency domain;

[0060] Step S204: rearrange the received signal model to obtain a vector form of the received signal model.

[0061] In this embodiment, when processing the received signal, first, the received signal of the non-uniform symmetrical linear microphone array is collected in a preset time domain for processing to generate a time domain received signal. Since the short-time Fourier transform can simultaneously analyze the signal in the time domain and the frequency domain f dimensions to effectively capture the time-varying characteristics of the signal, the frequency domain received signal is obtained by performing a short-time Fourier transform on the time domain received signal. Next, the frequency domain received signal is converted into a received signal model in the frequency domain, and by rearranging the vector of the received signal model, the vector form corresponding to the received signal model can be obtained. Among them, the time domain describes the relationship between the physical signal and time, and the time domain waveform of the signal can represent the change of the signal over time.

[0062] In step S203, a received signal model in the frequency domain is generated according to the received signal in the frequency domain, including:

[0063] Step S2031: Obtain the positions of the microphones according to the non-uniform symmetric linear array having an odd number of microphones

[0064] Step S2032: When n=0, according to the position of the microphone Get the frequency domain representation X0(f) of the incident signal source of interest x0(t) corresponding to the microphone position x0, where -N≤n≤N;

[0065] Step S2033: In the frequency domain received signal at the nth microphone in the non-uniform linear array, output the noisy signal Y according to the frequency domain representation in the frequency domain received signal n(f), expected source signal X n (f), additive noise signal V n (f) and the incident signal source X0(f), generate the corresponding received signal model with time frequency f in the frequency domain:

[0066] Where n is the position index of the microphone, n satisfies 2n+1=M, M is the number of microphones in the non-uniform symmetric linear array; f is the time frequency and f>0; -j is the imaginary unit and there is j 2 =-1; c is the speed of sound; θ s is the incident direction of the source signal, and t is the time in the time domain.

[0067] In this embodiment, after obtaining the frequency domain received signal, the position of the microphone is first obtained according to the non-uniform symmetrical linear array. Further, when n=0, the frequency domain representation X0(f) of the incident signal source x0(t) of interest corresponding to the microphone position x0 is obtained. Further, the output noisy signal Y represented in the frequency domain in the frequency domain received signal is obtained. n (f), expected source signal X n (f), additive noise signal V n (f), so that the corresponding received signal model with time frequency f in the frequency domain can be obtained Among them, considering the far-field sound source situation, the incident signal source x0(t) of interest is a plane wave propagating at the speed of sound (ie, c=340 m / s) in an anechoic environment.

[0068] In step S204, the received signal model is rearranged to obtain a vector form of the received signal model, including:

[0069] Step S2041: Receive signal model Arrange in vector form, and the vector form of the received signal model is y(f)=x(f)+v(f)=d(f,θ s )X0(f)+v(f);

[0070] Step S2042: According to the vector form of the received signal model, y(f)=x(f)+v(f)=d(f,θ s )X0(f)+v(f), and we get the noisy signal vector y(f)=[Y -N (f),…,Y0(f),…,Y N (f)] T , expected source signal vector x(f) = [X -N (f),…,X0(f),…,X N (f)] T , additive noise signal vector v(f) = [V-N (f),…,V0(f),…,V N (f)] T and a steering vector of length 2n+1

[0071] Where T is the permutation operator.

[0072] In this embodiment, after obtaining the received signal model Afterwards, the signal model can be rearranged into a vector form, i.e., y(f) = x(f) + v(f) = d(f,θ s )X0(f)+v(f), we can further get y(f)=[Y -N (f),…,Y0(f),…,Y N (f)] T , x(f)=[X -N (f),…,X0(f),…,X N (f)] T 、v(f)=[V -N (f),…,V0(f),…,V N (f)] T and Where y(f) is the noisy signal vector, x(f) is the desired source signal vector, v(f) is the additive noise signal vector, and d(f,θ s ) is a steering vector with a length of 2n+1.

[0073] Next, step S30 is executed to sample the positions of the microphones in the microphone array to obtain initial beamformer weights.

[0074] Before determining the beamformer weights of the microphone array, it is also necessary to sample the positions of the microphones in the microphone array to obtain the initial beamformer weights in advance.

[0075] In step S30, sampling is performed at each microphone position in the microphone array to obtain initial beamformer weights, including:

[0076] The initial beamformer weights are obtained by sampling different microphone positions in the microphone array through continuous Kaiser windows.

[0077] Among them, x n represents the position of the microphone in the array, and x n Satisfy the formula n is the position index of the microphone, and n satisfies -N≤n≤N; J0 is a first-kind zero-order modified Bessel function; β is a window shape factor, and β represents an adjustable parameter; W is a window support.

[0078] In this embodiment, for a non-uniform symmetrical linear microphone array, when sampling at each microphone position in the microphone array, continuous Kaiser window functions may be used to sample at different microphone positions, thereby obtaining the initial beamformer weights: Among them, the position x of the microphone in the array that needs to be used n The above formula should be satisfied n is the position index of the microphone, and n satisfies -N≤n≤N. By selecting the window support W=2x N When , there is only one adjustment parameter β left; for a specific window support W, the beam width can be kept constant by adjusting the parameter β.

[0079] Next, step S40 is executed to adjust and normalize each initial beamformer weight in the microphone array to obtain a beamformer weight.

[0080] After obtaining the initial beamformer weights at each microphone position in the microphone array by sampling using a continuous Kaiser window function, the initial beamformer weights are further adjusted to intermediate beamformer weights, and then the intermediate beamformer weights are normalized to obtain beamformer weights.

[0081] In step S40, each initial beamformer weight in the microphone array is adjusted and normalized to obtain a beamformer weight, including:

[0082] Step S401: Using the trapezoidal integration technique, the initial beamformer weights w of the outermost and inner microphones are k (x n ) are respectively multiplied by the corresponding microphone spacing △n to calculate and adjust to obtain an adjusted intermediate value of the beamformer weight;

[0083] Step S402: Normalize the intermediate values ​​of the beamformer weights to obtain the beamformer weights

[0084] The microphone spacing △n of the outermost microphone satisfies △n=x N -x N-1 , |n|=N, the microphone spacing △n of the outermost microphone satisfies

[0085] In this embodiment, in order to improve the adaptability to some closely spaced microphones, when adjusting the initial beamformer weights at each microphone position, the outermost microphones can be separated by a microphone spacing Δn (Δn satisfies Δn=x) by using a trapezoidal integration technique (TIT). N -x N-1 , |n|=N) to perform product calculation adjustment, and the outermost microphone is connected to the inner microphone by microphone spacing △n (△n satisfies ) is multiplied and adjusted to obtain the adjusted intermediate value of the beamformer weight. Among them, the microphone spacing △n satisfies the formula By using the trapezoidal integration technique (TIT) to adjust the weights across all frequencies in the microphone array, the effect of the closely spaced center sensor on the constant beamwidth can be reduced, thereby achieving the desired constant beamwidth at low frequencies.

[0086] Next, step S50 is executed to obtain an estimated value corresponding to the incident direction of the incident signal source through a constant beamwidth beamformer output according to the received signal model and the beamformer weight.

[0087] After obtaining the normalized beamformer weights, it is necessary to further combine the received signal model and then output the desired source signal X through a constant beamwidth beamformer according to the incident direction of the incident signal source. n (f) is the estimated value.

[0088] In step S50, according to the received signal model and the beamformer weight, an estimated value corresponding to the incident direction of the incident signal source is obtained through the constant beamwidth beamformer output, including:

[0089] Step S501: Obtain the incident direction θ of the incident signal source x0(t) s ;

[0090] Step S502: According to the incident direction θ of the incident signal source x0(t) s , the output of the constant beamwidth beamformer is as an estimate;

[0091] Where h(f) is the normalized beamformer weight of length 2N+1; * is the complex conjugate operator; H is the conjugate transpose operator; Z(f) is the estimated value of the desired source signal X0(f) in the frequency domain; d(f,θ) is the steering vector of length 2n+1; Y n (f) is the output noisy signal represented in the frequency domain; X0(f) is the desired signal source represented in the frequency domain; y(f) is the noisy signal vector represented in the frequency domain.

[0092] In this embodiment, in the process of outputting the estimated value of the constant beam width beamformer, when the incident direction of the incident signal source x0(t) is θ s When , the output of the constant beamwidth beamformer can be obtained as Thus, the estimated value Z(f) of the desired source signal X0(f) represented in the frequency domain is obtained by the output of the constant beam width beamformer, that is, a constant beam width with stable output is obtained.

[0093] See also Figure 2 , Figure 2 In the given embodiment, a position diagram located at the top is obtained by Kaiser window constant beamwidth beamforming based on a uniform symmetric linear array, wherein the number of microphones of the uniform symmetric linear array used is M=11, and the spacing between adjacent microphones is δ=3.5 cm. A position diagram located at the bottom is obtained by Kaiser window constant beamwidth beamforming of a non-uniform symmetric linear microphone array, wherein the number of microphones of the non-uniform symmetric linear array is M=11, and the coordinates of the microphone positions greater than 0 (when n≥1) are [3.5, 7.5, 16.5, 33.5, 86.5] cm.

[0094] See also Figure 3 and Figure 4 , Figure 3 and Figure 4 It can be seen from the given embodiments that the constant beamwidth beamforming method provided by the present invention can maintain the required constant beamwidth at a lower frequency.

[0095] See also Figure 5 , Figure 5 In the given embodiments, it can be seen that the constant beamwidth frequency range of the constant beamwidth beamforming method provided by the present invention is 1000 Hz larger than that based on the uniform symmetric line array method, that is, the constant beamwidth beamforming method provided by the present invention can be applied to lower frequencies and can maintain a constant beamwidth within a larger frequency range.

[0096] See also Figure 6 , Figure 6 In the given embodiments, it can be seen that when the frequency is less than 2000 Hz, compared with the constant beamwidth beamforming method based on a uniform symmetrical line array, the constant beamwidth beamforming method of the non-uniform symmetrical linear microphone array provided by the present invention has a larger directivity index (DI), that is, it can achieve higher directivity in low-frequency applications.

[0097] Please refer to 7. The present invention also provides a constant beamwidth beamforming system 11, including: a receiving module 111, used to obtain a received signal of a non-uniformly symmetrical microphone array; a processing module 112, used to perform signal processing based on time domain and frequency domain on the received signal to obtain a received signal model; a sampling module 113, used to sample each microphone position in the microphone array to obtain an initial beamformer weight; an adjustment module 114, used to adjust and normalize each initial beamformer weight in the microphone array to obtain a beamformer weight; and an output module 115, used to obtain an estimated value corresponding to the incident direction of the incident signal source through a constant beamwidth beamformer output according to the received signal model and the beamformer weight.

[0098] It should be noted that the constant beamwidth beamforming system 11 provided in the above embodiment and the constant beamwidth beamforming method provided in the above embodiment belong to the same concept, wherein the specific manner in which each module and unit performs the operation has been described in detail in the method embodiment, and will not be repeated here. In actual applications, the constant beamwidth beamforming system 11 provided in the above embodiment can distribute the above functions to different functional modules as needed, that is, divide the internal structure of the device into different functional modules to complete all or part of the functions described above, and this is not limited here.

[0099] See also Figure 8 The electronic device 1 may include a memory 12, a processor 13 and a bus, and may also include a computer program stored in the memory 12 and executable on the processor 13, such as a constant beamwidth beamforming program.

[0100] Among them, the memory 12 includes at least one type of readable storage medium, and the readable storage medium includes flash memory, mobile hard disk, multimedia card, card-type memory (for example: SD or DX memory, etc.), magnetic memory, disk, optical disk, etc. In some embodiments, the memory 12 can be an internal storage unit of the electronic device 1, such as a mobile hard disk of the electronic device 1. In other embodiments, the memory 12 can also be an external storage device of the electronic device 1, such as a plug-in mobile hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the electronic device 1. Further, the memory 12 can also include both an internal storage unit of the electronic device 1 and an external storage device. The memory 12 can not only be used to store application software and various types of data installed in the electronic device 1, such as constant beam width beamforming code, etc., but also can be used to temporarily store data that has been output or is to be output.

[0101] In some embodiments, the processor 13 may be composed of an integrated circuit, for example, a single packaged integrated circuit, or a plurality of packaged integrated circuits with the same or different functions, including one or more central processing units (CPUs), microprocessors, digital processing chips, graphics processors, and a combination of various control chips. The processor 13 is the control core (Control Unit) of the electronic device 1, and uses various interfaces and lines to connect various components of the entire electronic device 1, and executes or executes programs or modules (such as constant beamwidth beamforming programs, etc.) stored in the memory 12, and calls data stored in the memory 12 to execute various functions of the electronic device 1 and process data.

[0102] The processor 13 executes the operating system and various installed application programs of the electronic device 1. The processor 13 executes the application programs to implement the steps in the above-mentioned constant beamwidth beamforming method.

[0103] Exemplarily, the computer program may be divided into one or more modules, which are stored in the memory 12 and executed by the processor 13 to complete the present application. The one or more modules may be a series of computer program instruction segments capable of completing specific functions, which are used to describe the execution process of the computer program in the electronic device 1. For example, the computer program may be divided into a receiving module 111, a processing module 112, a sampling module 113, an adjustment module 114, and an output module 115.

[0104] The above-mentioned integrated unit implemented in the form of a software function module can be stored in a computer-readable storage medium, and the computer-readable storage medium can be non-volatile or volatile. The above-mentioned software function module is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, a computer device, or a network device, etc.) or a processor to perform part of the functions of the constant beamwidth beamforming method described in various embodiments of the present application.

[0105] In summary, the present invention discloses a constant beamwidth beamforming method, system, device and medium. By using a trapezoidal integration technique based on a non-uniform symmetrical linear array, each beamformer weight is multiplied by the microphone spacing under the non-uniform array, so that at low frequencies, the internal microphone sensors with smaller spacing are invalid due to the smaller weight assigned, and the external sensors with larger spacing are assigned a larger weight. In addition, by utilizing the symmetric properties of the non-uniform linear array, the array has the same spatial response to input signals of different frequencies within the main lobe width, effectively expanding the low-frequency range for maintaining the required constant beamwidth, thereby achieving a constant beamwidth at a lower frequency, that is, achieving a constant beamwidth within a larger frequency range, and improving directivity at low frequencies. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0106] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A constant beamwidth beamforming method, characterized in that: include: Acquire a received signal of a non-uniform symmetrical microphone array; Performing signal processing based on time domain and frequency domain on the received signal to obtain a received signal model; Sampling each microphone position in the microphone array to obtain an initial beamformer weight; Adjusting and normalizing each of the initial beamformer weights in the microphone array to obtain a beamformer weight; According to the received signal model and the beamformer weights, an estimated value corresponding to the incident direction of the incident signal source is obtained through a constant beamwidth beamformer output.

2. The constant beamwidth beamforming method according to claim 1, characterized in that: Performing signal processing based on time domain and frequency domain on the received signal to obtain a received signal model includes: Processing the received signal in a preset time domain to obtain a time domain received signal; Performing short-time Fourier transform on the time-domain received signal to obtain a frequency-domain received signal; Generate a received signal model in the frequency domain according to the received signal in the frequency domain; The received signal model is rearranged to obtain a vector form of the received signal model.

3. The constant beamwidth beamforming method according to claim 1, characterized in that: According to the frequency domain received signal, a received signal model in the frequency domain is generated, including: Based on a non-uniform symmetric linear array with an odd number of microphones, the positions of the microphones are obtained When n = 0, according to the position of the microphone Get the frequency domain representation X0(f) of the incident signal source of interest x0(t) corresponding to the microphone position x0, where -N≤n≤N; In the frequency domain received signal at the nth microphone in the non-uniform linear array, the output noisy signal Y represented in the frequency domain in the frequency domain received signal is n (f), expected source signal X n (f), additive noise signal V n (f) and the incident signal source X0(f), generate a received signal model with a corresponding time frequency of f in the frequency domain: Where n is the position index of the microphone, n satisfies 2n+1=M, M is the number of microphones in the non-uniform symmetric linear array; f is the time frequency and f>0; -j is the imaginary unit and there is j 2 =-1; c is the speed of sound; θ s is the incident direction of the source signal, and t is the time in the time domain.

4. The constant beamwidth beamforming method according to claim 3, characterized in that: Rearranging the received signal model to obtain a vector form of the received signal model includes: The received signal model Arrange in vector form, and obtain the vector form of the received signal model as y(f)=x(f)+v(f)=d(f,θ s )X0(f)+v(f); According to the vector form of the received signal model, y(f)=x(f)+v(f)=d(f,θ s )X0(f)+v(f), and we get the noisy signal vector y(f)=[Y -N (f),…,Y0(f),…,Y N (f)] T , expected source signal vector x(f) = [X -N (f),…,X0(f),…,X N (f)] T , additive noise signal vector v(f) = [V -N (f),…,V0(f),…,V N (f)] T and a steering vector of length 2n+1 Where T is the permutation operator.

5. The constant beamwidth beamforming method according to claim 1, characterized in that: Sampling each microphone position in the microphone array to obtain an initial beamformer weight includes: The initial beamformer weights are obtained by sampling different microphone positions in the microphone array through continuous Kaiser windows. Among them, x n represents the position of the microphone in the array, and x n Satisfy the formula n is the position index of the microphone, and n satisfies -N≤n≤N; J0 is a first-kind zero-order modified Bessel function; β is a window shape factor, and β represents an adjustable parameter; W is a window support.

6. The constant beamwidth beamforming method according to claim 5, characterized in that: Adjusting and normalizing each of the initial beamformer weights in the microphone array to obtain a beamformer weight, comprising: Using a trapezoidal integration technique, the initial beamformer weights w of the outermost and innermost microphones are k (x n ) are respectively multiplied by the corresponding microphone spacing △n to calculate and adjust to obtain an adjusted intermediate value of the beamformer weight; The beamformer weight intermediate value is normalized to obtain the beamformer weight The microphone spacing △n of the outermost microphone satisfies △n=x N -x N-1 , |n|=N, the microphone spacing △n of the outermost microphone satisfies 7. The constant beamwidth beamforming method according to claim 1, characterized in that: Obtaining an estimated value corresponding to the incident direction of an incident signal source through a constant beamwidth beamformer output according to the received signal model and the beamformer weights, including: Get the incident direction θ of the incident signal source x0(t) s ; According to the incident direction θ of the incident signal source x0(t) s , the output of the constant beamwidth beamformer is as the estimated value; Where h(f) is the normalized beamformer weight of length 2N+1; * is the complex conjugate operator; H is the conjugate transpose operator; Z(f) is the estimated value of the desired source signal X0(f) in the frequency domain; d(f,θ) is the steering vector of length 2n+1; Y n (f) is the output noisy signal represented in the frequency domain; X0(f) is the desired signal source represented in the frequency domain; y(f) is the noisy signal vector represented in the frequency domain.

8. A constant beamwidth beamforming system, characterized in that: include: A receiving module, used for acquiring a receiving signal of a non-uniform symmetrical microphone array; A processing module, used for performing signal processing based on time domain and frequency domain on the received signal to obtain a received signal model; A sampling module, used for sampling each microphone position in the microphone array to obtain an initial beamformer weight; An adjustment module, configured to adjust and normalize each of the initial beamformer weights in the microphone array to obtain a beamformer weight; as well as The output module is used to obtain an estimated value corresponding to the incident direction of the incident signal source through a constant beam width beamformer output according to the received signal model and the beamformer weight.

9. An electronic device, characterized in that: The electronic device comprises: one or more processors; A storage device for storing one or more programs, which, when executed by the one or more processors, enables the electronic device to implement the constant beamwidth beamforming method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed by a processor of a computer, the computer is caused to execute the constant beamwidth beamforming method according to any one of claims 1 to 7.

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