CN111261178B - Beam forming method and device - Google Patents
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- G10L21/00—Speech or voice signal processing techniques to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
- G10L21/02—Speech enhancement, e.g. noise reduction or echo cancellation
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- G10L21/00—Speech or voice signal processing techniques to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
- G10L21/02—Speech enhancement, e.g. noise reduction or echo cancellation
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- G10L21/00—Speech or voice signal processing techniques to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
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Abstract
The present disclosure provides a beam forming method and apparatus. The beam forming device divides the designated frequency range to obtain a preset number of frequency bands, applies the same response constraint on the central frequency of each frequency band in the time domain to obtain corresponding time domain coefficients, converts the time domain coefficients from the time domain to the frequency domain to obtain corresponding frequency domain coefficients, carries out band-pass filtering on the frequency domain coefficients so as to only keep the coefficients associated with the corresponding central frequency points, thus obtaining corresponding filter coefficients, synthesizes the filter coefficients to obtain corresponding beam forming coefficients, and carries out beam forming processing by using the beam forming coefficients. The present disclosure has no requirement for the number of microphone arrays and is applicable to microphone arrays of different array types.
Description
Technical Field
The present disclosure relates to the field of information processing, and in particular, to a beam forming method and apparatus.
Background
The speech signal belongs to a wideband signal, and for a beamforming algorithm based on a narrowband signal, its beam response will vary with the frequency of the signal. In order to enable the beam response to be unchanged with the change of the signal frequency, especially the frequency range of interest in the main lobe direction, the following two ideas are mainly adopted at present. The first way is to make the beams corresponding to different frequencies constant by changing the effective aperture of the array by utilizing the relationship between the frequencies and the apertures in the beam forming; the first way is to approximate the beam to be synthesized to the desired beam according to a predetermined criterion.
Disclosure of Invention
The inventors have found through research that in the first mode described above, the array shape is required to strictly meet the requirements of the extended structure, and the array size is required to be large, and the number of required array elements is large. In the second way described above, although an array of arbitrary shape can be used, since the bezier (Bessel) number needs to be kept to more than ten orders to have better accuracy, more array element data is still required.
To this end, the present disclosure provides a beamforming scheme to accommodate microphone arrays of different array element numbers.
According to an aspect of one or more embodiments of the present disclosure, there is provided a beam forming method including: dividing the designated frequency range to obtain a predetermined number of frequency bands; applying the same response constraint on the center frequency of each frequency band in the time domain to obtain corresponding time domain coefficients; converting the time domain coefficient from the time domain to the frequency domain to obtain a corresponding frequency domain coefficient; band-pass filtering is carried out on the frequency domain coefficients so as to only keep the coefficients associated with the corresponding center frequency points, thereby obtaining corresponding filter coefficients; synthesizing the filter coefficients to obtain corresponding beam forming coefficients; and carrying out beam forming processing by using the beam forming coefficient.
In some embodiments, converting the time domain coefficients from the time domain to the frequency domain comprises: expanding the time domain coefficient associated with the mth microphone by zero padding to obtain an expansion coefficient of the mth microphone, wherein the expansion coefficient of the mth microphone is an N-dimensional vector, N is the number of frequency bands, M is more than or equal to 1 and less than or equal to M, and M is the total number of the microphones; and converting the expansion coefficient of the mth microphone from the time domain to the frequency domain to obtain the frequency domain coefficient of the mth microphone at the center frequency point of the corresponding frequency band.
In some embodiments, band-pass filtering the frequency domain coefficients comprises: and setting the frequency domain coefficients corresponding to the frequency points except the nth frequency point to be zero for the mth microphone to obtain the filter coefficient of the mth microphone at the nth frequency point, wherein N is more than or equal to 1 and less than or equal to N.
In some embodiments, synthesizing the filter coefficients comprises: synthesizing the filter coefficients of the mth microphone at each frequency point to obtain the synthesized coefficient of the mth microphone; and synthesizing the synthesized coefficients of the microphones to obtain corresponding beam forming coefficients.
In some embodiments, the response constraints include: the response is a first specified value in the main lobe region of the sound wave incident angle theta and a second specified value in the side lobe region of the sound wave incident angle theta, the first specified value being greater than the second specified value.
In some embodiments, the first specified value is 1 and the second specified value is 0.
In some embodiments, the response constraint imposed in the time domain for the center frequency of each frequency band is associated with the center frequency of the respective frequency band, the angle of incidence θ of the sound wave, and the corresponding time domain coefficient.
According to another aspect of one or more embodiments of the present disclosure, there is provided a beam forming apparatus including: a frequency band dividing module configured to divide a specified frequency range to obtain a predetermined number of frequency bands; a time domain coefficient processing module configured to apply the same response constraint to the center frequency of each frequency band in the time domain to obtain a corresponding time domain coefficient; a conversion module configured to convert the time domain coefficients from the time domain to the frequency domain to obtain corresponding frequency domain coefficients; the filtering module is configured to carry out band-pass filtering on the frequency domain coefficients, and carry out band-pass filtering on the frequency domain coefficients so as to only keep the coefficients associated with the corresponding center frequency points, thereby obtaining corresponding filtering coefficients; the synthesis module is configured to synthesize the filter coefficients to obtain corresponding beam forming coefficients; and a beam forming processing module configured to perform beam forming processing using the beam forming coefficients.
In some embodiments, the conversion module is configured to expand the time domain coefficient associated with the mth microphone by zero padding to obtain an expansion coefficient of the mth microphone, wherein the expansion coefficient of the mth microphone is an N-dimensional vector, N is the number of frequency bands, 1.ltoreq.m.ltoreq.m, and M is the total number of microphones; and converting the expansion coefficient of the mth microphone from the time domain to the frequency domain to obtain the frequency domain coefficient of the mth microphone at the center frequency point of the corresponding frequency band.
In some embodiments, the filtering module is configured to set the frequency domain coefficients corresponding to the frequency points except the nth frequency point to zero for the mth microphone to obtain the filtering coefficients of the mth microphone at the nth frequency point, wherein 1.ltoreq.n.ltoreq.n.
In some embodiments, the synthesizing module is configured to synthesize the filter coefficients of the mth microphone at each frequency point to obtain synthesized coefficients of the mth microphone, and synthesize the synthesized coefficients of the microphones to obtain corresponding beamforming coefficients.
In some embodiments, the response constraint includes a response in a main lobe region of the sound wave incident angle θ being a first specified value and a response in a side lobe region of the sound wave incident angle θ being a second specified value, the first specified value being greater than the second specified value.
In some embodiments, the first specified value is 1 and the second specified value is 0.
In some embodiments, the response constraint imposed in the time domain for the center frequency of each frequency band is associated with the center frequency of the respective frequency band, the angle of incidence θ of the sound wave, and the corresponding time domain coefficient.
According to another aspect of one or more embodiments of the present disclosure, there is provided a beam forming apparatus including: a memory configured to store instructions; a processor coupled to the memory, the processor configured to perform a method according to any of the embodiments described above based on instructions stored in the memory.
According to another aspect of one or more embodiments of the present disclosure, there is provided a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions that, when executed by a processor, implement a method as referred to in any of the embodiments above.
Other features of the present disclosure and its advantages will become apparent from the following detailed description of exemplary embodiments of the disclosure, which proceeds with reference to the accompanying drawings.
Drawings
In order to more clearly illustrate the embodiments of the present disclosure or the solutions in the prior art, the drawings that are required for the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present disclosure, and that other drawings may be obtained according to these drawings without inventive faculty for a person skilled in the art.
Fig. 1 is an exemplary flow chart of a beamforming method of one embodiment of the present disclosure;
Fig. 2 is an exemplary block diagram of a beam forming apparatus of one embodiment of the present disclosure;
fig. 3 is an exemplary block diagram of a beam forming apparatus of another embodiment of the present disclosure;
fig. 4 is a schematic diagram of a beamforming scheme of an embodiment of the present disclosure.
Detailed Description
The following description of the technical solutions in the embodiments of the present disclosure will be made clearly and completely with reference to the accompanying drawings in the embodiments of the present disclosure, and it is apparent that the described embodiments are only some embodiments of the present disclosure, not all embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. All other embodiments, which can be made by one of ordinary skill in the art without inventive effort, based on the embodiments in this disclosure are intended to be within the scope of this disclosure.
The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present disclosure unless it is specifically stated otherwise.
Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description.
Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate.
In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.
Fig. 1 is an exemplary flow chart of a beamforming method of one embodiment of the present disclosure. In some embodiments, the method steps of the present embodiments may be performed by a beamforming apparatus.
In step 101, the specified frequency range is divided to obtain a predetermined number of frequency bands.
In some embodiments, the center frequency of each band is:
wherein N is more than or equal to 1 and less than or equal to N, N is the number of frequency bands, and Fs is the sampling frequency. For example, the sampling frequency is 16000Hz. Since the audio frequency range that can be perceived by the human ear is limited, only the first 100 frequency bands, i.e. the frequency range of 0-3093 Hz, can be considered here.
In step 102, the same response constraint is applied in the time domain to the center frequency of each band to obtain corresponding time domain coefficients.
In some embodiments, the response constraint imposed in the time domain for the center frequency of each frequency band is associated with the center frequency of the respective frequency band, the angle of incidence θ of the sound wave, and the corresponding time domain coefficient.
For example, assuming that the microphone position is P m＝[xm,ym]T, 0.ltoreq.m.ltoreq.M-1, M is the number of microphones, and the sound incident angle is θ, the beam response at the frequency f n is defined as:
Where J is a filter tap coefficient, e.g., J is 200. Is the coefficient to be designed, where the superscript t characterizes the time domain, i.e. the coefficient is a real number. Ts is the sampling period. τ m (θ) represents the time delay of the sound wave to the mth microphone with reference to the array origin. The corresponding calculation formula is as follows:
Where V is the propagation velocity of sound waves in air, v=340 m/s. Is provided with
Wherein the symbols areRepresenting the kronecker product. Thus, the beam response can be expressed as:
The main lobe width is set to be theta width (for example, the main lobe width is 30deg, of course, the main lobe width can be adjusted according to the need), and the whole angle range is set Is divided into a main lobe region Θ m＝[θ-0.5θwidth,θ+0.5θwidth and a side lobe region Θ S＝Θ-Θm.
In some embodiments, the desired constraints are: the response is a first specified value in the main lobe region of the sound wave incident angle theta and a second specified value in the side lobe region of the sound wave incident angle theta, the first specified value being greater than the second specified value. For example, the first specified value is 1 and the second specified value is 0. This is due to the following quadratic programming problem:
Where α is an equalization factor, e.g., 0.01, which of course can be adjusted as desired.
To facilitate solution using tools, the above formula can be further written as:
CTwt＝f (12)
wherein c= [ Re { s (f n,θ)},Im{s(fn,θ)}],f＝[1 0]T. Re { x } represents the real part of the complex number, im { x } represents the imaginary part of the complex number, and the superscript H represents the conjugate transpose.
Since the solution to the quadratic programming problem is known to those skilled in the art, it is not described here.
In step 103, the time domain coefficients are converted from the time domain to the frequency domain to obtain corresponding frequency domain coefficients.
In some embodiments, converting the time domain coefficients from the time domain to the frequency domain comprises: and expanding the time domain coefficient associated with the mth microphone by zero padding to obtain the expansion coefficient of the mth microphone, wherein the expansion coefficient of the mth microphone is an N-dimensional vector, N is the number of frequency bands, M is more than or equal to 1 and less than or equal to M, and M is the total number of the microphones.
Since N > J, zero padding is required for the time coefficients before transformation. For example, the time domain coefficients associated with the mth microphone are extended by zero padding to obtain the extension coefficient W m,exp of the mth microphone.
Wm,exp＝[ωm,0,...,ωm,J-1,0,...,0]T (14)
Where W m,exp is a column vector in N dimensions, representing the expansion coefficient of the mth microphone. Next, the following formula is used:
Wm,n＝FFT(Wm,exp) (15)
To obtain the frequency domain coefficient W m,n of the mth microphone at the nth center frequency point. Wherein the FFT is a fast fourier transform.
In step 104, the frequency domain coefficients are band-pass filtered so as to preserve only the coefficients associated with the corresponding center frequency points, thereby obtaining corresponding filter coefficients.
In some embodiments, for the mth microphone, the frequency domain coefficients corresponding to the frequency points except for the nth frequency point are set to zero to obtain the filter coefficient of the mth microphone at the nth frequency point, wherein N is greater than or equal to 1 and N is greater than or equal to N.
For example, for the coefficients of the mth microphone at the nth frequency point:
The band-pass filtered coefficients are:
in step 105, the filter coefficients are synthesized to obtain corresponding beamforming coefficients.
In some embodiments, synthesizing the filter coefficients includes: and synthesizing the filter coefficients of the mth microphone at each frequency point to obtain the synthesized coefficients of the mth microphone, and synthesizing the synthesized coefficients of the microphones to obtain the corresponding beam forming coefficients.
For example, after the coefficient of each frequency point is calculated, the coefficient synthesis may be performed as follows. For example, for the mth microphone, the result of the synthesis is:
Wherein the method comprises the steps of Is the coefficient of the mth microphone to the nth frequency point. Thus, the resulting beamforming coefficients are:
in step 106, a beamforming process is performed using the beamforming coefficients.
Since the corresponding beamforming process using beamforming coefficients is known to those skilled in the art, it is not described here.
In the beamforming method provided in the foregoing embodiments of the present disclosure, the specified frequency range is divided to obtain a predetermined number of frequency bands, the same response constraint is applied to the center frequency of each frequency band in the time domain to obtain a corresponding time domain coefficient, the time domain coefficient is converted from the time domain to the frequency domain to obtain a corresponding frequency domain coefficient, the frequency domain coefficient is band-pass filtered so as to retain only the coefficient associated with the corresponding center frequency point, thereby obtaining a corresponding filter coefficient, the filter coefficient is synthesized to obtain a corresponding beamforming coefficient, and the beamforming process is performed by using the beamforming coefficient. The present disclosure has no requirement for the number of microphone arrays and is applicable to microphone arrays of different array types. For example, the present disclosure is applicable to circular microphone arrays, as well as other arrays such as linear microphone arrays.
Fig. 2 is an exemplary flow chart of a beam forming apparatus of one embodiment of the present disclosure. As shown in fig. 2, the beam forming apparatus includes a band dividing module 21, a time domain coefficient processing module 22, a converting module 23, a filtering module 24, a synthesizing module 25, and a beam forming processing module 26.
The frequency band dividing module 21 is configured to divide a specified frequency range to obtain a predetermined number of frequency bands.
In some embodiments, the center frequency of each band is as shown in equation (1) above.
The time domain coefficient processing module 22 is configured to apply the same response constraint in the time domain to the center frequency of each frequency band to obtain the corresponding time domain coefficient.
In some embodiments, the response constraint imposed in the time domain for the center frequency of each frequency band is associated with the center frequency of the respective frequency band, the angle of incidence θ of the sound wave, and the corresponding time domain coefficient.
In some embodiments, the desired constraints are: the response is a first specified value in the main lobe region of the sound wave incident angle theta and a second specified value in the side lobe region of the sound wave incident angle theta, the first specified value being greater than the second specified value. For example, the first specified value is 1 and the second specified value is 0. For example, the above constraints can be attributed to the quadratic programming problem as described in the above formulas (9), (10). Since the solution to the quadratic programming problem is known to those skilled in the art, it is not described here.
The conversion module 23 is configured to convert the time domain coefficients from the time domain to the frequency domain to obtain corresponding frequency domain coefficients.
In some embodiments, the conversion module 23 is configured to expand the time domain coefficient associated with the mth microphone by zero padding to obtain an expansion coefficient of the mth microphone, where the expansion coefficient of the mth microphone is an N-dimensional vector, N is the number of frequency bands, 1.ltoreq.m.ltoreq.m, and M is the total number of microphones; and converting the expansion coefficient of the mth microphone from the time domain to the frequency domain to obtain the frequency domain coefficient of the mth microphone at the center frequency point of the corresponding frequency band.
For example, the time domain coefficients associated with the mth microphone may be extended by zero padding according to the above formula (14), and the time-frequency domain conversion may be performed according to the above formula (15).
The filtering module 24 is configured to bandpass filter the frequency domain coefficients, so as to preserve only the coefficients associated with the corresponding center frequency points, resulting in corresponding filter coefficients.
In some embodiments, the filtering module 24 is configured to set the frequency domain coefficients corresponding to the frequency points other than the nth frequency point to zero for the mth microphone to obtain the filtering coefficients of the mth microphone at the nth frequency point, wherein 1.ltoreq.n.ltoreq.n.
For example, the coefficients of the mth microphone at the nth frequency point may be bandpass filtered using the above formulas (16), (17).
The synthesis module 25 is configured to synthesize the filter coefficients to obtain corresponding beamforming coefficients.
In some embodiments, the synthesizing module 25 is configured to synthesize the filter coefficients of the mth microphone at each frequency point to obtain the synthesized coefficients of the mth microphone, and synthesize the synthesized coefficients of the microphones to obtain the corresponding beamforming coefficients.
For example, the coefficients may be combined according to the above formulas (18), (19) to obtain the corresponding beamforming coefficients.
The beamforming processing module 26 is configured to perform beamforming processing using beamforming coefficients.
Since the corresponding beamforming process using beamforming coefficients is known to those skilled in the art, it is not described here.
In the beamforming apparatus provided in the foregoing embodiments of the present disclosure, the specified frequency range is divided to obtain a predetermined number of frequency bands, the same response constraint is applied to the center frequency of each frequency band in the time domain to obtain a corresponding time domain coefficient, the time domain coefficient is converted from the time domain to the frequency domain to obtain a corresponding frequency domain coefficient, the frequency domain coefficient is band-pass filtered so as to retain only the coefficient associated with the corresponding center frequency point, thereby obtaining a corresponding filter coefficient, the filter coefficients are synthesized to obtain a corresponding beamforming coefficient, and the beamforming process is performed using the beamforming coefficient. The present disclosure has no requirement for the number of microphone arrays and is applicable to microphone arrays of different array types. For example, the present disclosure is applicable to circular microphone arrays, as well as other arrays such as linear microphone arrays.
Fig. 3 is an exemplary block diagram of a beam forming apparatus of another embodiment of the present disclosure. As shown in fig. 3, the beam forming means comprises a memory 31 and a processor 32.
The memory 31 is for storing instructions and the processor 32 is coupled to the memory 31, the processor 32 being configured to perform a method as referred to in any of the embodiments of fig. 1 based on the instructions stored by the memory.
As shown in fig. 3, the beam forming apparatus further comprises a communication interface 33 for information interaction with other devices. Meanwhile, the device also comprises a bus 34, and the processor 32, the communication interface 33 and the memory 31 are in communication with each other through the bus 34.
The memory 31 may comprise a high-speed RAM memory or may further comprise a non-volatile memory (non-volatile memory), such as at least one disk memory. The memory 31 may also be a memory array. The memory 31 may also be partitioned and the blocks may be combined into virtual volumes according to certain rules.
Further, the processor 32 may be a central processing unit CPU, or may be an application specific integrated circuit ASIC, or one or more integrated circuits configured to implement embodiments of the present disclosure.
The present disclosure also relates to a computer readable storage medium having stored thereon computer instructions which, when executed by a processor, implement a method as referred to in any of the embodiments of fig. 1.
Fig. 4 is a schematic diagram of a beamforming scheme of an embodiment of the present disclosure. As shown in fig. 4, a predetermined number of frequency bands are obtained by dividing a specified frequency range. The same response constraint is applied to the center frequency of each band in the time domain to obtain corresponding time domain coefficients. The time domain coefficients are converted from the time domain to the frequency domain through FFT to obtain corresponding frequency domain coefficients, and then the frequency domain coefficients are subjected to band-pass filtering in the frequency domain so as to only retain the coefficients associated with the corresponding center frequency points, thereby obtaining corresponding filtering coefficients. And finally, synthesizing the filter coefficients to obtain corresponding beam forming coefficients, thereby obtaining the beam forming coefficients in the whole interested frequency range. Then, a beam forming process is performed using the beam forming coefficient. This is applicable to microphone arrays of different array types, such as linear arrays and the like.
In some embodiments, the functional unit blocks described above may be implemented as general purpose processors, programmable logic controllers (Programmable Logic Controller, abbreviated as PLCs), digital signal processors (DIGITAL SIGNAL processors, abbreviated as DSPs), application Specific Integrated Circuits (ASICs), field-Programmable gate arrays (Field-Programmable GATE ARRAY, abbreviated as FPGAs), or other Programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or any suitable combination thereof for performing the functions described in the present disclosure.
It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program for instructing relevant hardware, where the program may be stored in a computer readable storage medium, and the storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.
The description of the present disclosure has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments were chosen and described in order to best explain the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.
Claims (10)
1. A method of beam forming, comprising:
dividing the designated frequency range to obtain a predetermined number of frequency bands;
applying the same response constraint on the center frequency of each frequency band in the time domain to obtain corresponding time domain coefficients;
Converting the time domain coefficient from the time domain to the frequency domain to obtain a corresponding frequency domain coefficient;
band-pass filtering is carried out on the frequency domain coefficients so as to only keep the coefficients associated with the corresponding center frequency points, thereby obtaining corresponding filter coefficients;
synthesizing the filter coefficients to obtain corresponding beam forming coefficients;
Carrying out beam forming processing by utilizing the beam forming coefficient;
Wherein synthesizing the filter coefficients comprises:
synthesizing the filter coefficients of the mth microphone at each frequency point to obtain a synthesized coefficient of the mth microphone, wherein M is more than or equal to 1 and less than or equal to M, and M is the total number of microphones;
synthesizing the synthesized coefficients of the microphones to obtain corresponding beam forming coefficients;
Wherein the response constraint comprises: the response in the main lobe region of the sound wave incident angle theta is a first specified value, and the response in the side lobe region of the sound wave incident angle theta is a second specified value, wherein the first specified value is larger than the second specified value, and the response constraint imposed on the center frequency of each frequency band in the time domain is associated with the center frequency of the corresponding frequency band, the sound wave incident angle theta and the corresponding time domain coefficient.
2. The method of claim 1, wherein converting the time domain coefficients from the time domain to the frequency domain comprises:
Expanding the time domain coefficient associated with the mth microphone by zero padding to obtain an expansion coefficient of the mth microphone, wherein the expansion coefficient of the mth microphone is an N-dimensional vector, and N is the number of frequency bands;
And converting the expansion coefficient of the mth microphone from the time domain to the frequency domain to obtain the frequency domain coefficient of the mth microphone at the center frequency point of the corresponding frequency band.
3. The method of claim 2, wherein band-pass filtering the frequency domain coefficients comprises:
And setting the frequency domain coefficients corresponding to the frequency points except the nth frequency point to be zero for the mth microphone to obtain the filter coefficient of the mth microphone at the nth frequency point, wherein N is more than or equal to 1 and less than or equal to N.
4. The method according to any one of claim 1 to 3, wherein,
The first specified value is 1 and the second specified value is 0.
5. A beam forming apparatus comprising:
A frequency band dividing module configured to divide a specified frequency range to obtain a predetermined number of frequency bands;
A time domain coefficient processing module configured to apply the same response constraint in the time domain to the center frequency of each frequency band to obtain a corresponding time domain coefficient, wherein the response constraint comprises: the response in the main lobe area of the sound wave incidence angle theta is a first specified value, the response in the side lobe area of the sound wave incidence angle theta is a second specified value, the first specified value is larger than the second specified value, and the response constraint applied to the central frequency of each frequency band in the time domain is related to the central frequency of the corresponding frequency band, the sound wave incidence angle theta and the corresponding time domain coefficient;
A conversion module configured to convert the time domain coefficients from the time domain to the frequency domain to obtain corresponding frequency domain coefficients;
The filtering module is configured to carry out band-pass filtering on the frequency domain coefficients, and carry out band-pass filtering on the frequency domain coefficients so as to only keep the coefficients associated with the corresponding center frequency points, thereby obtaining corresponding filtering coefficients;
The synthesis module is configured to synthesize the filter coefficients to obtain corresponding beam forming coefficients, wherein the filter coefficients of the mth microphone at each frequency point are synthesized to obtain synthesis coefficients of the mth microphone, the synthesis coefficients of the microphones are synthesized to obtain corresponding beam forming coefficients, M is greater than or equal to 1 and less than or equal to M, and M is the total number of the microphones;
And a beam forming processing module configured to perform beam forming processing using the beam forming coefficients.
6. The apparatus of claim 5, wherein,
The conversion module is configured to expand the time domain coefficient associated with the mth microphone through zero padding to obtain an expansion coefficient of the mth microphone, wherein the expansion coefficient of the mth microphone is an N-dimensional vector, and N is the number of frequency bands; and converting the expansion coefficient of the mth microphone from the time domain to the frequency domain to obtain the frequency domain coefficient of the mth microphone at the center frequency point of the corresponding frequency band.
7. The apparatus of claim 6, wherein,
The filtering module is configured to set the frequency domain coefficients corresponding to the other frequency points except the nth frequency point to zero for the mth microphone so as to obtain the filtering coefficient of the mth microphone at the nth frequency point, wherein N is more than or equal to 1 and less than or equal to N.
8. The device according to any one of claims 5-7, wherein,
The first specified value is 1 and the second specified value is 0.
9. A beam forming apparatus comprising:
A memory configured to store instructions;
A processor coupled to the memory, the processor configured to perform the method of any of claims 1-4 based on instructions stored by the memory.
10. A computer readable storage medium storing computer instructions which, when executed by a processor, implement the method of any one of claims 1-4.
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