Sound field partition control method and related device

Abstract

The invention provides a sound field partition control method and a related device, and relates to the technical field of sound field control. The sound field partition control method comprises the following steps: acquiring a bright region transfer function matrix and a dark region transfer function matrix of a target sound field; obtaining a bright area expected sound pressure vector of the target sound field; in the frequency domain, taking the control target represented by the target function as a solving target, taking the time domain constraint condition as a solving constraint condition, and solving a filter coefficient matrix of the loudspeaker array; wherein the time domain constraint condition is used for constraining the time domain coefficients except the previous target order to be 0 when the filter coefficients obtained by solving are converted from the frequency domain to the time domain; the target function is expressed based on a bright region transfer function matrix, a dark region transfer function matrix, a bright region expected sound pressure vector and a to-be-solved filter coefficient matrix; and based on the filter coefficient matrix, controlling the loudspeaker array to perform audio playing. According to the technical scheme provided by the invention, the problem that the sound field partition control effect needs to be improved in the prior art can be solved.

Description

Technical Field

[0001] This application relates to the field of sound field control technology, and more specifically, to a sound field zoning control method and related apparatus. Background Technology

[0002] Sound field zoning refers to dividing the sound field into different zones within a specific physical space using technical means, allowing the audio playback effect of each zone to be controlled independently. For example, within the limited space of a vehicle cabin, it provides independent and non-interfering audio services to passengers in different zones. The driver's zone needs to clearly receive navigation voice and driving prompts, the passenger's zone can play music, and the rear zone can watch movies and TV shows. At the same time, the audio signals in each zone do not interfere with each other, ensuring a personalized listening experience for each passenger.

[0003] The key to sound field zoning control lies in designing the filter coefficients of the loudspeakers to adjust the sound pressure distribution in different areas. However, although traditional frequency domain algorithms (such as FFT-based spectrum analysis) can precisely control each frequency point, the control parameters between adjacent frequency points differ greatly, resulting in severe tailing of the filter's time domain response and easy time domain aliasing, which affects the sound field zoning control effect. Summary of the Invention

[0004] Based on the defects and shortcomings of the prior art, this application proposes a sound field zoning control method and related apparatus, which can solve the problem that the sound field zoning control effect in the prior art needs to be improved.

[0005] According to a first aspect of the embodiments of this application, a sound field zoning control method is provided, used to determine the filter coefficients of a loudspeaker array within a target space, the loudspeaker array being used to form a zone-controllable target sound field within the target space, the target sound field including a bright zone and a dark zone, the method comprising: Obtain the bright area transfer function matrix and the dark area transfer function matrix of the target sound field; Obtain the expected sound pressure vector in the bright area of ​​the target sound field; In the frequency domain, the control objective, represented by the objective function, is used as the solution objective, and the time-domain constraints are used as the solution constraints to solve for the filter coefficient matrix of the loudspeaker array. The time-domain constraints are used to ensure that all time-domain coefficients of the solved filter coefficients, except for the order of the target, are zero when transformed from the frequency domain to the time domain. The objective function is represented based on the bright-area transfer function matrix, the dark-area transfer function matrix, the bright-area desired sound pressure vector, and the filter coefficient matrix to be solved. Based on the filter coefficient matrix, the speaker array is controlled to play audio.

[0006] In this application, a time-domain constraint matrix is ​​added when solving for the filter coefficients in the frequency domain. This time-domain constraint mechanism must be considered during the calculation of the filter coefficients, ensuring that the filter coefficients calculated in the frequency domain have a predetermined length of zero at the end. Similarly, after converting the filter coefficients from the frequency domain to the time domain, the predetermined length of zero also remains at the end, thus guaranteeing the effective length in the time domain. The obtained filter coefficients are embedded into the corresponding speakers. Before playing audio through the speaker array, the audio signal can be adjusted using the obtained filter coefficients to achieve the target sound field. Because the effective time-domain order of the filter is controlled by the time-domain constraint, time-domain aliasing problems can be avoided. Furthermore, because the length of the time-domain filter coefficients can be precisely controlled, shorter filter coefficients can be designed, and shorter filter coefficients do not cause longer reverberation, thus ensuring playback sound quality.

[0007] In some optional embodiments, the time-domain constraint condition includes: the product of a pre-set time-domain constraint matrix and the filter coefficient matrix to be solved is 0; The time-domain constraint matrix is ​​used to constrain the time-domain coefficients obtained by solving the filter coefficients to be 0 when the filter coefficients are transformed from the frequency domain to the time domain, except for the previous target order.

[0008] In this application, by using the product of the time-domain constraint matrix and the filter coefficient matrix to be solved as 0 as a strong time-domain constraint condition for frequency-domain calculation, the sound field zoning control problem can be transformed into a constrained optimization problem. This allows for precise control of the time-domain order of the calculated filter and effectively avoids low-frequency performance loss caused by time-domain aliasing.

[0009] In some optional embodiments, the control objective, expressed as a target function, is the solution objective, and the time-domain constraints are the solution constraints. Solving for the filter coefficient matrix of the loudspeaker array includes: Determine the null space of the time-domain constraint matrix; The filter coefficient matrix is ​​linearly represented by the basis vectors of the null space to obtain a first expression for the filter coefficient matrix; wherein, in the first expression, each basis vector corresponds to an unknown coefficient; Substitute the first expression into the objective function, and use the control objective represented by the objective function as the solution objective to solve for the unknown coefficients; The filter coefficient matrix is ​​solved based on the unknown coefficients obtained from the solution and the first expression.

[0010] In this application, the effective number of the filter can be controlled through the time-domain constraint matrix, which avoids time-domain aliasing and constrains the longest reverberation time of the filter, thus ensuring a certain level of sound quality. Furthermore, the null-space method is used to simultaneously process frequency domain partitioning and time-domain tail suppression, ensuring the performance of frequency domain partitioning and the degree of freedom in frequency band processing. Moreover, using the null-space method to solve strong constraints avoids the matrix non-definite problem caused by using the Lagrange multiplier method. Simultaneously, the null-space method reduces the dimensionality of the solution space, thereby saving computational resources.

[0011] In some alternative embodiments, the time-domain constraint matrix is ​​constructed from the inverse Fourier transform matrix.

[0012] In this application, the time-domain constraint matrix is ​​constructed from the inverse Fourier transform matrix. During construction, the following requirements must be met: while converting the filter coefficients in the frequency domain to filter coefficients in the time domain, control which points in the time domain are equal to 0. Based on the time-domain constraint matrix, frequency domain partitioning and time-domain tail suppression are handled, ensuring that the optimized filter's time-domain response has no excessively long tail, thereby avoiding time-domain aliasing problems.

[0013] In some optional embodiments, microphones are provided in both the bright area and the dark area, and the acquisition of the bright area transfer function matrix and the dark area transfer function matrix of the target sound field includes: Control the loudspeaker array to output a sweep frequency signal, and control the microphone to receive the sweep frequency signal; Based on the sweep frequency signal output by the loudspeaker array and the sweep frequency signal received by the microphone, the bright area transfer function matrix and the dark area transfer function matrix of the target sound field are determined.

[0014] In this application, the bright area transfer function matrix and dark area transfer function matrix of the target sound field can be obtained by sweeping the frequency signal, which is simple and convenient to operate.

[0015] In some alternative embodiments, the control objective includes minimizing the sum of the bright area reconstruction error and the dark area acoustic energy.

[0016] In this application, minimizing the sum of the reconstruction error in the bright area and the acoustic energy in the dark area is taken as the control objective, which can effectively improve the sound field zoning control effect. In addition, weighting coefficients can be set separately for the reconstruction error in the bright area and the acoustic energy in the dark area. By changing the weighting coefficients, the sound field zoning control effect can be adjusted, thereby improving the flexibility of the sound field zoning control effect.

[0017] In some alternative embodiments, the target space includes the vehicle's cabin space.

[0018] The core requirement of in-vehicle sound field zoning is to provide independent and non-interfering audio services for passengers in different areas within a limited cabin space. However, the small cabin space, compact seat layout, and complex sound wave reflections present significant challenges to sound field control: on the one hand, it is necessary to precisely control the reconstruction effect of sound in the target area to ensure sound quality and loudness; on the other hand, it is necessary to minimize sound leakage to non-target areas and reduce interference. The sound field zoning control method provided in this application can better meet the needs of vehicle sound field zoning and improve the sound field zoning control effect within the cabin space.

[0019] According to a second aspect of the embodiments of this application, a sound field zoning control device is provided, used to determine the filter coefficients of a loudspeaker array within a target space, the loudspeaker array being used to form a zone-controllable target sound field within the target space, the target sound field including a bright zone and a dark zone, the device comprising: The first acquisition module is used to acquire the bright area transfer function matrix and the dark area transfer function matrix of the target sound field; The second acquisition module is used to acquire the bright area expected sound pressure vector of the target sound field; The solution module is used to solve for the filter coefficient matrix of the loudspeaker array in the frequency domain, using the control objective represented by the objective function as the solution objective and the time-domain constraints as the solution constraints. The time-domain constraints are used to ensure that all time-domain coefficients of the solved filter coefficients, except for the initial objective order, are zero when transformed from the frequency domain to the time domain. The objective function is represented based on the bright-area transfer function matrix, the dark-area transfer function matrix, the bright-area desired sound pressure vector, and the filter coefficient matrix to be solved. The control module is used to control the speaker array to play audio based on the filter coefficient matrix.

[0020] According to a third aspect of the embodiments of this application, an electronic device is provided, including: a memory and a processor; The memory is connected to the processor and is used to store programs; The processor is used to implement the method as described in the first aspect by running a program in the memory.

[0021] According to a fourth aspect of the embodiments of this application, a storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the method described in the first aspect.

[0022] According to a fifth aspect of the embodiments of this application, a computer program product or a computer program is provided, the computer program product including the computer program, wherein a processor executes the computer program to implement the steps in the method as described in the first aspect. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0024] Figure 1 This is a flowchart illustrating a sound field zoning control method provided in an embodiment of this application.

[0025] Figure 2 This is a block diagram of a sound field zoning control device provided in an embodiment of this application.

[0026] Figure 3 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] Application Overview The core objective of sound field zoning control is to create a personalized audio experience that is independent and undisturbed for listeners in different locations within a shared physical space (such as a car cabin, family living room, or office). This technology adjusts the audio signals output by a speaker array arranged in the space, utilizing the principles of beamforming and destructive interference of sound waves to create a clear and faithful sound field in the target area (i.e., the bright zone (BZ)), while attenuating sound energy to a negligible level in the non-target area (i.e., the dark zone (DZ)).

[0029] The key to achieving high-performance sound field zoning lies in designing precise filter coefficients for each speaker. These coefficients determine how the input audio signal is adjusted so that the sound waves emitted by each speaker are superimposed in space to produce the desired sound field zoning effect.

[0030] In related technologies, sound field zoning control technology is mainly divided into two categories: frequency domain zoning algorithms and time domain zoning algorithms.

[0031] The frequency domain partitioning algorithm converts the audio signal and the speaker transfer function to the frequency domain through Fourier transform, independently constructs optimization objectives for different frequency points, solves the filter coefficients at each frequency point, and converts them back to the time domain through inverse Fourier transform to drive the speaker.

[0032] Time-domain partitioning algorithms process signals directly in the time domain, characterizing transmission properties with impulse response and achieving sound field control through adaptive filtering or convolution operations. For example, the Least Mean Square (LMS) algorithm can be used to estimate the leakage signal in the dark area in real time and generate an inverse cancellation signal, or a directional beam can be formed by adjusting the delay and amplitude of the speaker's time-domain signal.

[0033] While existing frequency-domain partitioning algorithms can achieve precise control at each frequency point, their independent optimization of each frequency point can lead to significant differences in control parameters between adjacent frequencies, resulting in a lack of continuity and severe tailing in the filter's time-domain response. This causes time-domain aliasing and affects sound quality. Forcing the coefficients of tailed filters to zero can significantly degrade partitioning performance. Some existing frequency-domain optimization algorithms can reduce filter tailing by applying flatness constraints, but these weak constraints are not designed to solve time-domain aliasing and therefore cannot precisely control the filter order. While time-domain partitioning algorithms do not suffer from time-domain aliasing, they lack frequency-domain optimization capabilities and cannot achieve differentiated control across different frequency bands. Especially in the high-frequency range, insufficient speaker time-domain response accuracy can lead to a decline in control performance.

[0034] To overcome the above-mentioned technical problems, this application provides a solution that introduces a time-domain anti-aliasing constraint mechanism on the basis of the frequency domain partitioning algorithm. This mechanism can accurately control the time-domain order of the calculated filter, and while achieving precise control per frequency point, it can also effectively avoid low-frequency performance loss caused by time-domain aliasing.

[0035] Exemplary methods This application provides a sound field zoning control method, which is applied to electronic devices. The electronic devices can be terminal devices, such as tablet computers, laptops, desktop computers, vehicle terminals, mobile phones, etc., or servers, such as cloud servers.

[0036] This electronic device executes the sound field zoning control method, primarily to determine the filter coefficients of each speaker in the speaker array within the target space. The solved filter coefficients are then used to control the speaker array to play audio, forming the target sound field. A speaker's filter can include multiple coefficients, meaning the filter order is at least two.

[0037] The target space mentioned herein may include, but is not limited to: the vehicle's cabin space, interior space (indoor living room space), or other physical spaces where speaker arrays can be deployed and where zoned sound fields can be formed based on speaker arrays.

[0038] The target sound field includes bright and dark areas. Taking a vehicle cabin as an example, the bright area of ​​the target sound field can be the front row area or the driver's seat area, where effective sound is expected to be heard, while the dark area can be the rear row area or the passenger seat area, where effective sound is not expected to be heard. The bright and dark areas can be different for different sound fields. Different sound fields can be divided according to the usage scenario. For example, in a scenario where the driver needs to hear navigation sounds, the bright area can be the driver's seat area, and the dark area can be any area in the cabin other than the driver's seat area. In a scenario where the passenger needs to hear music without wanting the music to interfere with the driver's listening, the bright area can be the passenger seat area, and the dark area can be the driver's seat area. The division of bright and dark areas can be implemented according to actual needs.

[0039] The loudspeaker array includes multiple loudspeakers, and the location of each loudspeaker within the target space can be deployed according to actual needs.

[0040] The method is described in detail below through some embodiments. The following embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0041] like Figure 1 As shown, the sound field zoning control method may include steps 101 to 104, as described below.

[0042] Step 101: Obtain the bright area transfer function matrix and dark area transfer function matrix of the target sound field.

[0043] The transfer function matrix for the bright area is used to characterize the propagation characteristics of the audio signal from the sound source (i.e., the loudspeaker) to the receiving point in the bright area; the transfer function matrix for the dark area is used to characterize the propagation characteristics of the audio signal from the sound source to the receiving point in the dark area.

[0044] Methods for obtaining the bright area transfer function matrix and the dark area transfer function matrix may include, but are not limited to: reading the pre-stored bright area transfer function matrix and dark area transfer function matrix from the memory of an electronic device, or calculating the bright area transfer function matrix and dark area transfer function matrix through an acoustic model.

[0045] Step 102: Obtain the expected sound pressure vector of the bright area of ​​the target sound field.

[0046] The bright area and the dark area can each include at least one control point. The expected sound pressure vector of the bright area is the vector formed by the expected sound pressure of each control point in the bright area.

[0047] Methods for obtaining the expected sound pressure vector in the bright area may include: reading a pre-saved expected sound pressure vector in the bright area from the memory of an electronic device.

[0048] For a pre-saved desired sound pressure level vector (SPL) in the bright area, the desired sound field can be pre-recorded using microphones (i.e., microphones; generally, the number of microphones deployed in the bright area corresponds to the number of control points). The desired SPL is then obtained based on the recorded audio of the desired sound field. The desired sound field can be pre-equalized by a sound engineer within the target space, with the modulated filter built into the speakers to make the entire target space sound natural and pleasant. The microphones at the bright area control points can be existing microphones in the target space or additional microphones set up specifically to obtain the desired SPL; the choice depends on the actual needs.

[0049] Step 103: In the frequency domain, using the control objective represented by the objective function as the solution objective and the time domain constraints as the solution constraints, solve for the filter coefficient matrix of the loudspeaker array.

[0050] The control objective described here can be understood as an optimization objective, used to optimize the solution results of the filter coefficients. This ensures that when the speaker array is driven by the solved filter coefficients for audio playback, the reconstruction effect of effective sound in the bright area is improved, while the sound energy of effective sound in the dark area is suppressed. Simply put, it aims to make the sound field in the bright area approach the target sound field, while minimizing the sound energy in the dark area. This control objective may include, for example, minimizing the reconstruction error in the bright area and minimizing the sound energy in the dark area, or minimizing the sum of the reconstruction error in the bright area and the sound energy in the dark area.

[0051] The time-domain constraints described here are used to constrain the obtained filter coefficients to satisfy the condition that, when transformed from the frequency domain to the time domain, all time-domain coefficients except those of the first 500 orders are zero; that is, the coefficient sequence ends with a certain length of zero values. For example, if a filter has an order of 1000, this time-domain constraint can be used to constrain the obtained filter coefficients to satisfy the condition that, when transformed from the frequency domain to the time domain, all time-domain coefficients except those of the first 500 orders are zero.

[0052] This application's embodiments are based on the principle that frequency domain multiplication equals time domain convolution. For example, assuming the time domain length of the speaker's filter coefficients is *m*, and the time domain length of the input audio signal is *n*, then the length of the signal after time domain convolution is *m+n-1*. However, when solving this problem in the frequency domain, both signals need to be padded with zeros to a length of *m+n-1* before performing a Fourier transform. After frequency domain multiplication, an inverse Fourier transform is then performed back to the time domain to obtain the same result as time domain convolution. Solving for filter coefficients in the frequency domain requires that the effective time domain length be *m* to ensure there is no deviation caused by time domain aliasing. Related technologies convert the filter coefficients from the frequency domain to the time domain and then forcibly set some coefficient values ​​to zero, but this leads to a significant degradation in partitioning performance, affecting the partitioning isolation effect.

[0053] To address this, this application adds a time-domain constraint mechanism to the frequency-domain algorithm. When calculating filter coefficients in the frequency domain, this time-domain constraint mechanism must be considered to ensure that the calculated filter coefficients end with a required length of zero. Similarly, when the filter coefficients are converted from the frequency domain to the time domain, they will also end with the required length of zero, thus guaranteeing the effective time-domain length. For example, in the frequency domain, if the filter order is 1000 and the effective time-domain length is 500, then under the time-domain constraint, 1000 filter coefficients are obtained, with the last 500 coefficients all being 0.

[0054] Step 104: Based on the obtained filter coefficient matrix, control the speaker array to play audio.

[0055] After obtaining the filter coefficients of the speaker array through the above steps, the obtained filter coefficients can be embedded into the corresponding speakers. When playing audio through the speaker array, the audio signal can be adjusted using the obtained filter coefficients to achieve the target sound field. Because the effective order of the filter in the time domain is controlled by time-domain constraints, time-domain aliasing problems can be avoided. Furthermore, because the length of the time-domain filter coefficients can be precisely controlled, shorter filter coefficients can be designed. Shorter filter coefficients do not cause longer reverberation, thus ensuring playback sound quality and improving the listening experience.

[0056] In some alternative embodiments, the objective function may include the bright area reconstruction error represented by the bright area transfer function matrix, the filter coefficient matrix to be solved, and the expected sound pressure vector of the bright area, and the dark area sound energy represented by the bright area transfer function matrix and the filter coefficient matrix to be solved.

[0057] Given that the control objective includes minimizing the sum of the reconstruction error in the bright area and the acoustic energy in the dark area, weighting coefficients can be set separately for the reconstruction error in the bright area and the acoustic energy in the dark area in the objective function. By changing the weighting coefficients, the sound field zoning control effect can be adjusted, thereby improving the flexibility of the sound field zoning control effect.

[0058] In some optional embodiments, the above-mentioned time-domain constraint condition can be: the product of the pre-set time-domain constraint matrix and the filter coefficient matrix to be solved is 0, that is: the product of the pre-set time-domain constraint matrix and the filter coefficient matrix to be solved is 0 as the time-domain constraint condition, so as to realize the time-domain constraint when solving the filter coefficients.

[0059] This time-domain constraint matrix is ​​used to ensure that the time-domain coefficients obtained from the constraint solution are set to 0 when transformed from the frequency domain to the time domain, except for the first target order. This time-domain preset matrix is ​​pre-designed, and its specific design can be implemented according to actual needs.

[0060] Given that the control objective is to minimize the sum of the reconstruction error in the bright area and the sound energy in the dark area, assuming that the loudspeaker array in the target space includes L loudspeakers, the target sound field includes 2M control points (i.e., 2M microphones), and the frequency domain resolution (i.e., the number of frequency points) is K, then the control objective (i.e., the objective function) for the sound pressure levels in the bright and dark areas in the frequency domain can be defined as follows: (1) In formula (1), T represents the time-domain constraint matrix, and q represents the filter coefficient matrix to be solved (with dimension q). The English word "st" stands for "subject to," indicating that it is constrained by something. What follows are the time-domain constraints described in this embodiment, i.e. The meanings of the other parameters in formula (1) are as follows: Indicates the reconstruction error of the bright area. Indicates the acoustic energy in the dark area. Represents the transfer function matrix of the bright area (dimension: ), The transfer function matrix for the dark area (dimension 1) ), This represents the sound pressure vector of the target sound field in the bright area. The time-domain constraint matrix, Let be the control filter vector to be solved (i.e., the filter coefficient matrix to be solved). and These parameters represent the weighting parameters for the reconstruction error in the bright area and the acoustic energy in the dark area, respectively. The weighting of the reconstruction error in the bright area and the acoustic energy in the dark area can be adjusted for different frequency bands, providing greater flexibility.

[0061] The meaning of formula (1) above is: to find a q that minimizes the control objective. Furthermore, the q obtained must satisfy the following condition: This constraint is a strong constraint.

[0062] In this case, half of the filter coefficients need to be 0, so the dimension of the time-domain constraint matrix T can be K\2×LK.

[0063] Optionally, in some embodiments, the null space method can be used to solve for the filter coefficients, as described below.

[0064] Step 103: Using the control objective represented by the objective function as the solution objective and the time-domain constraints as the solution constraints, solve for the filter coefficient matrix of the loudspeaker array. This may include steps A1 to A4, as described below: Step A1: Determine the null space of the time-domain constraint matrix.

[0065] Suppose we have a 3×4 matrix A: To find the null space of matrix A, we need to solve the system of equations A. x =0, here x It is a four-dimensional vector. x = .

[0066] based on Ax =0 yields the following two equations: Since there are only two independent equations and a total of four unknowns, there are two free variables. You can choose... and As free variables. Representing the main variables using free variables. and : but + .

[0067] and and Then these are a set of basis vectors (i.e., orthogonal basis) of the null space of matrix A, and the null space of matrix A is the space spanned by these two basis vectors. Any matrix satisfying A x vector = 0 x Both can be represented as a linear combination of these two basis vectors.

[0068] The null space of the time-domain constraint matrix in this embodiment can be obtained by solving the process shown in the example above.

[0069] Step A2: The filter coefficient matrix is ​​linearly represented by the basis vectors of the null space of the time-domain constraint matrix to obtain the first expression of the filter coefficient matrix.

[0070] In the first expression, each basis vector corresponds to an unknown coefficient, such as in the example above. and .

[0071] In this embodiment, a null space matrix N can be introduced, satisfying... The column vectors of the null space matrix N are the basis vectors of the null space of the time-domain constraint matrix.

[0072] In the example above, it is mentioned that any condition satisfying A x vector = 0 x All can be represented as a linear combination of basis vectors in the null space; therefore, for strongly constrained... In this equation, q can be linearly represented by the basis vectors N of the null space of the time-domain constraint matrix, yielding the first expression (2), as shown below: (2) in, This can be understood as in the example above. and That is, the unknown coefficient in the first expression.

[0073] Step A3: Substitute the first expression into the objective function, and use the control objective represented by the objective function as the solution objective to solve for the unknown coefficients.

[0074] Step A4: Solve for the filter coefficient matrix based on the unknown coefficients obtained from the solution and the first expression.

[0075] For steps A3 and A4, we will use formula (1) as an example to illustrate them.

[0076] After obtaining the first expression (2), substitute the first expression (2) into formula (1) to obtain formula (3), as shown below: (3) in, , = , respectively, are the reduced-dimensional transfer function matrices for the bright and dark areas. Equation (3) means: solving for a... This minimizes the control objective. It can be solved using the least squares method. .

[0077] Since the constraint Tq=0 can be satisfied simply by solving for the filter coefficient matrix q in the null space, i.e., by representing q using an orthogonal basis of the null space, then after linearly representing q using the null space matrix N, no further addition is needed. The constraint is that the q calculated at this point must satisfy Tq=0.

[0078] The obtained Substituting into the first expression (2), we can obtain the solution. .

[0079] In this embodiment, the effective order of the filter can be controlled through the time-domain constraint matrix, which avoids time-domain aliasing and constrains the longest reverberation time of the filter, ensuring a certain level of sound quality. Furthermore, the null-space method is used to simultaneously process frequency domain partitioning and time-domain tail suppression, ensuring the performance of frequency domain partitioning and the degree of freedom in frequency band processing. Moreover, using the null-space method to solve strong constraints avoids the matrix non-definite problem caused by using the Lagrange multiplier method. Simultaneously, the null-space method reduces the dimensionality of the solution space, saving computational resources.

[0080] Optionally, the time-domain constraint matrix in this embodiment is constructed from the inverse Fourier transform matrix, and the following requirements need to be met during construction: while converting the filter coefficients in the frequency domain to the filter coefficients in the time domain, control which points in the time domain are equal to 0.

[0081] When it is necessary to control the coefficients of half the order (referring to the latter half) to 0, T can be made to... .

[0082] in, The half-band constraint of the inverse Fourier transform is used to limit the length of the filter's time-domain response and suppress tailing. By incorporating it into the time-domain constraint matrix and simultaneously processing frequency domain partitioning and time-domain tailing suppression using the null space method, the optimized filter's time-domain response can be free of excessively long tails, thereby avoiding time-domain aliasing problems.

[0083] In some optional embodiments, step 101: obtaining the bright area transfer function matrix and the dark area transfer function matrix of the target sound field may include steps B1 and B2, as described below: Step B1: Control the loudspeaker array to output a sweep frequency signal and control the microphone to receive the sweep frequency signal.

[0084] Step B2: Determine the bright zone transfer function matrix and dark zone transfer function matrix of the target sound field based on the sweep frequency signal output by the loudspeaker array and the sweep frequency signal received by the microphone.

[0085] In this embodiment, loudspeakers within the target space can output sweep signals in their original state, and these sweep signals are received by microphones at each control point in both the bright and dark zones. Then, based on the sweep signals output by the loudspeaker array and received by the microphones, the bright zone transfer function matrix and the dark zone transfer function matrix of the target sound field are determined. For example, based on the sweep signals output by the loudspeaker array and received by the microphones, the geometric structure of the acoustic model is established, and the bright zone transfer function matrix and the dark zone transfer function matrix are obtained using methods such as Finite Element Analysis (FEA), Boundary Element Method (BEM), and Statistical Energy Analysis (SEA). The geometric structure of the acoustic model may include, but is not limited to, the sound source (i.e., loudspeaker), the transmission medium, and the receiving point (i.e., microphone).

[0086] In summary, the technical solution provided in this application, by adding strong time-domain constraints, transforms the sound field zoning control problem into a constrained optimization solution. This allows for precise control of the time-domain filter order, ensuring that frequency-domain calculations do not introduce time-domain aliasing, indirectly improving low-frequency isolation. Simultaneously, shorter filters are less affected by reflected sound, which also increases the system's robustness to some extent. Compared to traditional frequency-domain algorithms, this technical solution, by applying strong time-domain constraints, effectively suppresses filter tailing, eliminates time-domain aliasing caused by rapid frequency-domain convolution, improves the actual sound field isolation, and effectively reduces reverberation in bright areas, enhancing the listening experience. Compared to traditional time-domain algorithms, this technical solution retains the ability to control frequency-by-frequency in the frequency domain, allowing for precise adjustment of the sound pressure ratio at each frequency point in both bright and dark areas, thus improving the sound field zoning control effect.

[0087] Exemplary device Accordingly, this application also provides a sound field zoning control device for use in electronic devices, which may be terminal devices such as tablet computers, laptops, desktop computers, vehicle terminals, mobile phones, etc., or servers such as cloud servers.

[0088] This sound field zoning control device is mainly used to determine the filter coefficients of each loudspeaker in the loudspeaker array within the target space, so as to control the loudspeaker array to play audio and form the target sound field by solving for the filter coefficients. The filter of a loudspeaker can include multiple coefficients, that is, the filter order is at least two.

[0089] The target space mentioned herein may include, but is not limited to: the vehicle's cabin space, interior space (indoor living room space), or other physical spaces where speaker arrays can be deployed and where zoned sound fields can be formed based on speaker arrays.

[0090] The target sound field includes bright and dark areas. Taking a vehicle cabin as an example, the bright area of ​​the target sound field can be the front row area or the driver's seat area, where effective sound is expected to be heard, while the dark area can be the rear row area or the passenger seat area, where effective sound is not expected to be heard. The bright and dark areas can be different for different sound fields. Different sound fields can be divided according to the usage scenario. For example, in a scenario where the driver needs to hear navigation sounds, the bright area can be the driver's seat area, and the dark area can be any area in the cabin other than the driver's seat area. In a scenario where the passenger needs to hear music without wanting the music to interfere with the driver's listening, the bright area can be the passenger seat area, and the dark area can be the driver's seat area. The division of bright and dark areas can be implemented according to actual needs.

[0091] The loudspeaker array includes multiple loudspeakers, and the location of each loudspeaker within the target space can be deployed according to actual needs.

[0092] like Figure 2 As shown, the device may include: The first acquisition module 201 is used to acquire the bright area transfer function matrix and the dark area transfer function matrix of the target sound field.

[0093] The second acquisition module 202 is used to acquire the expected sound pressure vector of the target sound field in the bright area.

[0094] The solver module 203 is used to solve the filter coefficient matrix of the loudspeaker array in the frequency domain, with the control objective represented by the objective function as the solution objective and the time domain constraints as the solution constraints.

[0095] The time-domain constraint is used to constrain the time-domain coefficients obtained by solving the filter coefficients to be 0 when the frequency domain is transformed to the time domain, except for the first objective order; the objective function is represented based on the bright area transfer function matrix, the dark area transfer function matrix, the bright area expected sound pressure vector, and the filter coefficient matrix to be solved.

[0096] The control module 204 is used to control the speaker array to play audio based on the filter coefficient matrix.

[0097] In some alternative embodiments, the time-domain constraint condition includes: the product of a pre-set time-domain constraint matrix and the filter coefficient matrix to be solved is 0.

[0098] The time-domain constraint matrix is ​​used to constrain the time-domain coefficients obtained by solving the filter coefficients to be 0 when the filter coefficients are transformed from the frequency domain to the time domain, except for the previous target order.

[0099] In some alternative embodiments, the solver module 203 may include: A determining unit is used to determine the null space of the time-domain constraint matrix.

[0100] The processing unit is used to linearly represent the filter coefficient matrix using the basis vectors of the null space to obtain a first expression for the filter coefficient matrix.

[0101] In the first expression, each basis vector corresponds to an unknown coefficient.

[0102] The first solving unit is used to substitute the first expression into the objective function and solve for the unknown coefficients using the control objective represented by the objective function as the solving objective.

[0103] The second solving unit is used to solve the filter coefficient matrix based on the unknown coefficients obtained from the solution and the first expression.

[0104] In some alternative embodiments, the time-domain constraint matrix is ​​constructed from the inverse Fourier transform matrix.

[0105] In some optional embodiments, both the bright area and the dark area are equipped with microphones, and the first acquisition module may include: The control unit is used to control the loudspeaker array to output a sweep frequency signal and to control the microphone to receive the sweep frequency signal; The determining unit is used to determine the bright area transfer function matrix and the dark area transfer function matrix of the target sound field based on the sweep frequency signal output by the loudspeaker array and the sweep frequency signal received by the microphone.

[0106] In some alternative embodiments, the control objective includes minimizing the sum of the bright area reconstruction error and the dark area acoustic energy.

[0107] In some alternative embodiments, the target space includes the vehicle's cabin space.

[0108] The sound field zoning control device provided in this embodiment belongs to the same application concept as the sound field zoning control method provided in the above embodiments of this application. It can execute the sound field zoning control method provided in any of the above embodiments of this application and has the corresponding functional modules and beneficial effects of the execution method. Technical details not described in detail in this embodiment can be found in the specific processing content of the sound field zoning control method provided in the above embodiments of this application, and will not be repeated here.

[0109] It should be understood that the modules in the above map-using device can be implemented by a processor calling software. For example, the device includes a processor connected to a memory containing instructions. The processor calls the instructions stored in the memory to implement any of the above methods or to implement the functions of each unit of the device. The processor can be a general-purpose processor, such as a CPU or microprocessor, and the memory can be internal or external to the device. Alternatively, the units in the device can be implemented as hardware circuits. By designing the hardware circuits, some or all of the unit functions can be implemented. The hardware circuit can be understood as one or more processors. For example, in one implementation, the hardware circuit is an ASIC, and the functions of some or all of the above units are implemented by designing the logical relationships between the components within the circuit. In another implementation, the hardware circuit can be implemented by a PLD, such as an FPGA, which can include a large number of logic gates. The connection relationships between the logic gates are configured through configuration files to implement the functions of some or all of the above units. All units of the above device can be implemented entirely by a processor calling software, entirely by hardware circuits, or partially by a processor calling software with the remaining parts implemented by hardware circuits.

[0110] In this application embodiment, a processor is a circuit with signal processing capabilities. In one implementation, the processor can be a circuit with instruction reading and execution capabilities, such as a CPU, microprocessor, GPU, or DSP. In another implementation, the processor can implement certain functions through the logical relationships of hardware circuits. These logical relationships are fixed or reconfigurable. For example, the processor may be a hardware circuit implemented as an ASIC or PLD, such as an FPGA. In a reconfigurable hardware circuit, the process of the processor loading a configuration document and configuring the hardware circuit can be understood as the processor loading instructions to implement the functions of some or all of the above units. Furthermore, it can also be a hardware circuit designed for artificial intelligence, which can be understood as an ASIC, such as an NPU, TPU, or DPU.

[0111] As can be seen, each unit in the above device can be one or more processors (or processing circuits) configured to implement the above methods, such as: CPU, GPU, NPU, TPU, DPU, microprocessor, DSP, ASIC, FPGA, or a combination of at least two of these processor forms.

[0112] Furthermore, the units in the above devices can be integrated in whole or in part, or they can be implemented independently. In one implementation, these units are integrated together and implemented in the form of a System-on-Chip (SoC). The SoC may include at least one processor for implementing any of the above methods or implementing the functions of the units in the device. The at least one processor may be of different types, such as CPU and FPGA, CPU and artificial intelligence processor, CPU and GPU, etc.

[0113] Exemplary electronic devices This application also provides an electronic device, such as... Figure 3 As shown, the electronic device includes a memory 300 and a processor 310.

[0114] The memory 300 is connected to the processor 310 and is used to store programs.

[0115] The processor 310 is used to implement the sound field zoning control method in the above embodiments by running the program stored in the memory 300.

[0116] Specifically, the aforementioned electronic device may also include: a communication interface 320, an input device 330, an output device 340, and a bus 350.

[0117] The processor 310, memory 300, communication interface 320, input device 330, and output device 340 are interconnected via a bus. Among them: Bus 350 may include a pathway for transmitting information between various components of a computer system.

[0118] The processor 310 can be a general-purpose processor, such as a general-purpose central processing unit (CPU), a microprocessor, etc., or an application-specific integrated circuit (ASIC), or one or more integrated circuits used to control the execution of the program of the present invention. It can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an off-the-shelf programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0119] Processor 310 may include a main processor, as well as a baseband chip, modem, etc.

[0120] The memory 300 stores a program that executes the technical solution of this invention, and may also store an operating system and other key business functions. Specifically, the program may include program code, which includes computer operation instructions. More specifically, the memory 300 may include read-only memory (ROM), other types of static storage devices capable of storing static information and instructions, random access memory (RAM), other types of dynamic storage devices capable of storing information and instructions, disk storage, flash memory, etc.

[0121] Input device 330 may include a device for receiving user input data and information, such as a keyboard, mouse, camera, scanner, light pen, voice input device, touch screen, pedometer, or gravity sensor.

[0122] Output device 340 may include devices that allow information to be output to a user, such as a display screen, printer, speaker, etc.

[0123] The communication interface 320 may include a device that uses any transceiver to communicate with other devices or communication networks, such as Ethernet, Radio Access Network (RAN), Wireless Local Area Network (WLAN), etc.

[0124] The processor 310 executes the program stored in the memory 300 and calls other devices, which can be used to implement the various steps in the sound field zoning control method provided in the above embodiments of this application.

[0125] Exemplary computer program products and storage media In addition to the methods and devices described above, embodiments of this application may also be computer program products, which include computer program instructions that, when executed by a processor, cause the processor to perform the steps in the sound field zoning control method described in the embodiments of this application.

[0126] The aforementioned computer program product can be implemented through hardware, software, or a combination thereof. In one optional embodiment, the computer program product is specifically embodied in a computer storage medium; in another optional embodiment, the computer program product is specifically embodied in a software product, such as a software development kit (SDK), etc.

[0127] The computer program product can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of this application. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0128] Furthermore, embodiments of this application may also be storage media storing a computer program, which is executed by a processor of the steps in the sound field zoning control method described in the embodiments of this application.

[0129] In addition, embodiments of this application may also be chips, which include processors and data interfaces. The processor reads instructions stored in the memory through the data interface to execute the steps in the sound field zoning control method described in the embodiments of this application.

[0130] For the foregoing method embodiments, in order to simplify the description, they are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because according to this application, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0131] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For apparatus embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0132] The steps in the methods of the various embodiments of this application can be adjusted, merged, or deleted in order according to actual needs, and the technical features described in each embodiment can be replaced or combined.

[0133] The modules and sub-modules in the devices and terminals in the various embodiments of this application can be merged, divided, and deleted according to actual needs.

[0134] It should be understood that the disclosed terminals, devices, and methods can be implemented in other ways, given the several embodiments provided in this application. For example, the terminal embodiments described above are merely illustrative. For instance, the division of modules or sub-modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple sub-modules or modules may be combined or integrated into another module, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or modules, and may be electrical, mechanical, or other forms.

[0135] The modules or submodules described as separate components may or may not be physically separate. The components that constitute a module or submodule may or may not be physical modules or submodules; that is, they may be located in one place or distributed across multiple network modules or submodules. Some or all of the modules or submodules can be selected to achieve the purpose of this embodiment's solution, depending on actual needs.

[0136] Furthermore, the functional modules or sub-modules in the various embodiments of this application can be integrated into one processing module, or each module or sub-module can exist physically separately, or two or more modules or sub-modules can be integrated into one module. The integrated modules or sub-modules described above can be implemented in hardware or in the form of software functional modules or sub-modules.

[0137] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0138] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software unit executed by a processor, or a combination of both. The software unit can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0139] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A method for controlling sound field zoning, characterized in that, The method for determining filter coefficients of a loudspeaker array within a target space, the loudspeaker array being used to form a zone-controlled target sound field within the target space, the target sound field including bright and dark zones, comprises: Obtain the bright area transfer function matrix and the dark area transfer function matrix of the target sound field; Obtain the expected sound pressure vector in the bright area of ​​the target sound field; In the frequency domain, the control objective, represented by the objective function, is used as the solution objective, and the time-domain constraints are used as the solution constraints to solve for the filter coefficient matrix of the loudspeaker array. The time-domain constraints are used to ensure that all time-domain coefficients of the solved filter coefficients, except for the order of the target, are zero when transformed from the frequency domain to the time domain. The objective function is represented based on the bright-area transfer function matrix, the dark-area transfer function matrix, the bright-area desired sound pressure vector, and the filter coefficient matrix to be solved. Based on the filter coefficient matrix, the speaker array is controlled to play audio.

2. The sound field zoning control method according to claim 1, characterized in that, The time-domain constraint condition includes: the product of the pre-set time-domain constraint matrix and the filter coefficient matrix to be solved is 0; The time-domain constraint matrix is ​​used to constrain the time-domain coefficients obtained by solving the filter coefficients to be 0 when the filter coefficients are transformed from the frequency domain to the time domain, except for the previous target order.

3. The sound field zoning control method according to claim 2, characterized in that, The solution objective, expressed as a target function, is used as the objective, and the time-domain constraints are used as the constraint conditions. Solving for the filter coefficient matrix of the loudspeaker array includes: Determine the null space of the time-domain constraint matrix; The filter coefficient matrix is ​​linearly represented by the basis vectors of the null space to obtain a first expression for the filter coefficient matrix; wherein, in the first expression, each basis vector corresponds to an unknown coefficient; Substitute the first expression into the objective function, and use the control objective represented by the objective function as the solution objective to solve for the unknown coefficients; The filter coefficient matrix is ​​solved based on the unknown coefficients obtained from the solution and the first expression.

4. The sound field zoning control method according to claim 2 or 3, characterized in that, The time-domain constraint matrix is ​​constructed from the inverse Fourier transform matrix.

5. The sound field zoning control method according to claim 1, characterized in that, Both the bright area and the dark area are equipped with microphones. The step of acquiring the bright area transfer function matrix and the dark area transfer function matrix of the target sound field includes: Control the loudspeaker array to output a sweep frequency signal, and control the microphone to receive the sweep frequency signal; Based on the sweep frequency signal output by the loudspeaker array and the sweep frequency signal received by the microphone, the bright area transfer function matrix and the dark area transfer function matrix of the target sound field are determined.

6. The sound field zoning control method according to claim 1, characterized in that, The control objectives include minimizing the sum of the reconstruction error in the bright area and the acoustic energy in the dark area.

7. The sound field zoning control method according to claim 1, characterized in that, The target space includes the vehicle's cabin space.

8. A sound field zoning control device, characterized in that, The device is used to determine the filter coefficients of a loudspeaker array within a target space, the loudspeaker array being used to form a zone-controlled target sound field within the target space, the target sound field including bright and dark zones, and the device comprises: The first acquisition module is used to acquire the bright area transfer function matrix and the dark area transfer function matrix of the target sound field; The second acquisition module is used to acquire the bright area expected sound pressure vector of the target sound field; The solution module is used to solve for the filter coefficient matrix of the loudspeaker array in the frequency domain, with the control objective represented by the objective function as the solution objective and the time-domain constraints as the solution constraints. The time-domain constraints are used to ensure that all time-domain coefficients of the solved filter coefficients, except for the order of the target, are zero when transformed from the frequency domain to the time domain. The objective function is represented based on the bright area transfer function matrix, the dark area transfer function matrix, the bright area desired sound pressure vector, and the filter coefficient matrix to be solved. The control module is used to control the speaker array to play audio based on the filter coefficient matrix.

9. An electronic device, characterized in that, include: Memory and processor; The memory is connected to the processor and is used to store programs; The processor is used to implement the sound field zoning control method as described in any one of claims 1 to 7 by running a program in the memory.

10. A computer program product, characterized in that, The computer program product stores a computer program, which, when executed by a processor, implements the sound field zoning control method as described in any one of claims 1 to 7.

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