An active noise reduction method and device for narrow-band noise, a storage medium and a terminal

Abstract

The application discloses a kind of active narrow-band noise reduction method, device, storage medium and terminal, comprising the following steps: obtaining engine speed, initial sound field, error signal and the control order required in multichannel system, secondary loudspeaker unit quantity, error microphone control point quantity;The following steps are continuously executed until the preset iteration number is reached: according to engine speed, the angular frequency corresponding to each control order is calculated, and the first cosine reference signal and the first sine reference signal are constructed based on angular frequency;According to the amplitude correction of first cosine reference signal and first sine reference signal by weighting matrix factor, second cosine reference signal, second sine reference signal and filter reference signal are obtained;According to filter reference signal and error signal, update control weight optimization loudspeaker output;The optimized loudspeaker output is superimposed with initial sound field.The application greatly improves the noise reduction effect.

Description

Technical Field

[0001] This invention relates to the field of narrowband noise technology, and more specifically to an active noise reduction method, apparatus, storage medium, and terminal for narrowband noise. Background Technology

[0002] In active control of automotive engine noise, the multi-channel noise reduction system consists of multiple control orders, secondary speaker units, and error microphone control points. Its theoretical basis is to continuously iterate relevant parameters through the FxLMS algorithm (Filtered-x Least Mean Square) so that the secondary sound source generates a sound wave with the opposite phase to the primary sound source at the error microphone, thereby minimizing the sound field.

[0003] However, the amplitude of the reference signal constructed in the prior art is usually kept constant or defaults to 1, causing the system to be unable to effectively track changes in the error signal; in addition, due to the introduction of the secondary transfer function Significant differences in amplitude response exist across different frequencies and channels, causing inconsistent responses from active noise cancellation systems to different speaker channels and frequencies. This necessitates adjusting different step sizes for different situations to ensure system convergence speed and noise reduction effectiveness. Furthermore, the workload increases with the number of channels. Dynamically adjusting and controlling multiple frequencies in active noise cancellation requires inputting different parameters for different states and frequencies, further complicating the operation.

[0004] Therefore, how to overcome the shortcomings of existing technologies using effective methods has become an urgent technical challenge. Summary of the Invention

[0005] The purpose of this invention is to address the above-mentioned problems by providing an active noise reduction method, apparatus, storage medium, and terminal for narrowband noise.

[0006] The technical solution of this invention is: an active noise reduction method for narrowband noise, comprising the following steps: acquiring engine speed, initial sound field, error signal e(n), and the required control order I, number of secondary speaker units J, and number of error microphone control points K in the multi-channel system; continuously executing the following steps until a preset number of iterations is reached: calculating the angular frequency corresponding to each control order based on the engine speed. Based on angular frequency Constructing the first cosine reference signal and the first sine reference signal According to the weighted matrix factors For the first cosine reference signal and the first sine reference signal Amplitude correction is performed to obtain the second cosine reference signal. Second sine reference signal Based on the second cosine reference signal Second sine reference signal Obtain the filtered reference signal Where i, j, k, I, J, and K are all positive integers, i = 1, 2, ..., I, j = 1, 2, ..., J, and k = 1, 2, ..., K; according to the filtered reference signal The control weights are updated and the speaker output is optimized using the error signal e(n); the optimized speaker output is then superimposed on the initial sound field.

[0007] As an improvement to an embodiment of the present invention, the weighted matrix factor It is a J×J diagonal matrix.

[0008] As an improvement to an embodiment of the present invention, the weighted matrix factor The element Ai,j = 1 / max( ),in, Let be the secondary transfer function value corresponding to the i-th frequency control point, the j-th channel, and the k-th microphone.

[0009] As an improvement to an embodiment of the present invention, the first cosine reference signal The first sinusoidal reference signal .

[0010] As an improvement to an embodiment of the present invention, the second cosine reference signal The second sinusoidal reference signal .

[0011] As an improvement to this embodiment of the invention, the filtered reference signal specifically includes: the second cosine reference signal. Second sine reference signal A weighted combination is performed, and the weight coefficients are determined based on the discrete Fourier transform results of the secondary transfer function.

[0012] As an improvement to this embodiment of the invention, the update of the control weights includes: updating the control weights using an adaptive algorithm based on the filtered reference signal and the error signal e(n).

[0013] To achieve one of the above-mentioned objectives, one embodiment of the present invention provides an active noise reduction device for narrowband noise, comprising the following modules: a data acquisition module, used to acquire engine speed, initial sound field, and the required control order I, number of secondary speaker units J, and number of error microphone control points K in the multi-channel system; and an execution module, used to continuously execute the following steps until a preset number of iterations is reached: calculating the angular frequency corresponding to each control order based on the engine speed. Based on angular frequency Constructing the first cosine reference signal and the first sine reference signal According to the weighted matrix factors For the first cosine reference signal and the first sine reference signal Amplitude correction is performed to obtain the second cosine reference signal. Second sine reference signal Based on the second cosine reference signal Second sine reference signal Obtain the filtered reference signal Where i, j, k, I, J, and K are all positive integers, i = 1, 2, ..., I, j = 1, 2, ..., J, and k = 1, 2, ..., K; based on the filtered reference signal The control weights are updated and the speaker output is optimized using the error signal e(n); the optimized speaker output is then superimposed on the initial sound field.

[0014] To achieve one of the above-mentioned objectives, one embodiment of the present invention provides a storage medium storing program instructions, which, when executed, implement the active noise reduction method for narrowband noise as described in any of the preceding claims.

[0015] To achieve one of the above-mentioned objectives, one embodiment of the present invention provides an electronic terminal, including a processor and a memory, wherein the memory stores program instructions, and the processor executes the program instructions to implement the active noise reduction method for narrowband noise as described in any of the preceding claims.

[0016] The active noise reduction method, apparatus, storage medium, and terminal for narrowband noise provided in this invention have the following advantages: By introducing a weighted correction mechanism for the amplitude of the reference signal and determining the values ​​of each element based on the characteristics of the secondary transfer function, the error convergence curves of different frequencies under the same system parameters are consistent. This solves the problem of inconsistent system response to different speaker channels and frequencies caused by large differences in the amplitude response of the secondary transfer function at different frequencies and channels. It also avoids the tedious operation of frequently adjusting parameters to adapt to different situations, greatly reduces the complexity of parameter tuning, and significantly improves the noise reduction effect. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the active noise reduction method for narrowband noise described in this invention.

[0018] Figure 2 This is a comparison of the convergence curves of the active noise reduction method for narrowband noise described in this invention and existing methods;

[0019] Figure 3This is a comparison chart of the noise reduction effects of the active noise reduction method for narrowband noise described in this invention and existing methods;

[0020] Figure 4 This is a schematic diagram of the structure of the active noise reduction device for narrowband noise described in this invention;

[0021] Figure 5 This is a schematic diagram of the structure of the electronic terminal described in this invention. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the scope of protection of the present invention.

[0023] If the present invention involves orientation (e.g., up, down, left, right, front, back, outside, inside, etc.) when described, then the orientations involved need to be defined.

[0024] The scope of the embodiments described herein includes the entire scope of the claims and all available equivalents thereof. Throughout this document, the terms “first,” “second,” etc., are used only to distinguish one element from another without requiring or implying any actual relationship or order between the elements. Indeed, a first element can also be referred to as a second element, and vice versa. Furthermore, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a structure, apparatus, or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a structure, apparatus, or device. Without further limitations, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the structure, apparatus, or device that includes said element. The various embodiments described herein are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably.

[0025] The terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" used in this document to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing this document and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention. In the description herein, unless otherwise specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two elements, or direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0026] Embodiment 1 of the present invention provides an active noise reduction method for narrowband noise, such as... Figure 1 As shown, it includes the following steps:

[0027] Step 101: Obtain engine speed, initial sound field, error signal e(n), and the required control order I, number of secondary speaker units J, and number of error microphone control points K in the multi-channel system;

[0028] In practice, the engine speed can be obtained from the engine control system's speed sensor via CAN bus or a dedicated signal acquisition module. The initial sound field is acquired before engine operation by using a microphone array located inside the vehicle or in the test environment, adapted to the error microphone control point positions, to collect environmental noise field data without active noise reduction intervention. The error signal e(n) is acquired by the error microphone installed in the target noise reduction area. The control order I corresponds to the engine's main order noise. The number of secondary speaker units J is set according to the noise reduction space size, noise distribution, and control accuracy requirements, outputting reverse-phase sound waves to cancel noise. The number of error microphone control points K is based on the monitoring requirements of the noise reduction effect, with microphones strategically placed at noise-sensitive points and points of drastic sound field changes to provide real-time feedback of the noise-reduced error signal.

[0029] Step 102: Continue executing the following steps until the preset number of iterations is reached: Calculate the angular frequency corresponding to each control order based on the engine speed. Based on angular frequency Constructing the first cosine reference signal and the first sine reference signal According to the weighted matrix factors For the first cosine reference signal and the first sine reference signal Amplitude correction is performed to obtain the second cosine reference signal. Second sine reference signal Based on the second cosine reference signal Second sine reference signal Obtain the filtered reference signal Where i, j, k, I, J, and K are all positive integers, i = 1, 2, ..., I, j = 1, 2, ..., J, and k = 1, 2, ..., K; according to the filtered reference signal The control weights are updated and the speaker output is optimized using the error signal e(n); the optimized speaker output is then superimposed on the initial sound field.

[0030] Here, the first cosine reference signal The first sinusoidal reference signal This generates an inverse basis signal with the same frequency as the primary noise, achieving frequency matching. To address the convergence imbalance between different channels caused by differences in the secondary transfer function, a weighting matrix factor is introduced. The second cosine reference signal The second sinusoidal reference signal Subsequently, in order to simulate the transmission characteristics of the secondary channel and make the weight updates more closely match the actual acoustic path, the second cosine reference signal was used. Second sine reference signal Obtain the filtered reference signal The weighted matrix factor It is a J×J diagonal matrix. The weighted matrix factor The element Ai,j = 1 / max( ),Right now in, Let be the secondary transfer function value corresponding to the i-th frequency control point, the j-th channel, and the k-th microphone. The amplitude of the secondary transfer function. This reflects the transfer gain from the secondary sound source to the error microphone. The maximum value represents the part of the secondary transfer function that has the most significant impact on noise reduction at that channel or order. Taking the reciprocal to correct the reference signal amplitude is to ensure that the convergence speed of the most influential part dominates, avoiding divergence caused by excessive gain in a certain channel, thereby balancing the convergence of multiple channels. Figure 2 The figure shows a comparison of the convergence curves of the active noise reduction method for narrowband noise described in this invention and existing methods. It can be seen that when the parameters are constant, the error convergence curves of the active noise reduction method for narrowband noise described in this invention are consistent at different points in the transfer function amplitude and phase. It can be understood that this is beneficial for maintaining system stability and achieving rapid parameter tuning.

[0031] In this embodiment, the filtered reference signal specifically includes: the second cosine reference signal. Second sine reference signal A weighted combination is performed, and the weight coefficients are determined based on the discrete Fourier transform results of the secondary transfer function.

[0032] Here, the filtered reference signal ; Among them, the weighting coefficient For secondary transmission The real and imaginary parts of the Discrete Fourier Transform can be obtained by calculating the transfer function through Fourier transform in an anechoic chamber environment by inputting a frequency sweep signal to each speaker-microphone channel. The real and imaginary parts of .

[0033] In this embodiment, the update of the control weights includes: updating the control weights using an adaptive algorithm based on the filtered reference signal and the error signal e(n).

[0034] Here, the FxLMS algorithm can be used to update the control weights. This algorithm is a classic algorithm in the field of narrowband active noise reduction, which minimizes the error signal power by iteratively adjusting the weights. The control weights can be adjusted according to... , Update, in which, The step size factor can range from 0.001 to 0.1. This range balances convergence speed and stability in automotive and industrial noise reduction scenarios with varying noise intensities and channel numbers. The error signal... The mean and expected value can be calculated by the following formula. , .in, The optimal weighting coefficients can be obtained through offline identification in an anechoic chamber environment, by inputting standard narrowband noise, collecting error signals, and fitting them using the least squares method; or based on identification theory, by constructing a secondary channel model and solving for the optimal weights through the inverse model. Weighting matrix factors This reflects the amplitude correction for different channels or frequencies; Matrix operations reflect secondary transfer functions The impact of differences on the statistical characteristics of the error signal e(n). The active noise reduction method for narrowband noise described in this invention can adjust the output of the secondary sound source. In practical noise reduction, Figure 3 This figure compares the noise reduction performance of the active noise reduction method for narrowband noise described in this invention with existing methods, showing the impact of different numbers of channels and error microphones on the performance at the control point. It can be seen from the figure that when a secondary transfer function is introduced... Subsequently, the convergence characteristics of existing methods completely change. At this point, to counteract the effects of the transfer function, system parameters need to be readjusted. However, the active noise reduction method for narrowband noise described in this invention maintains stable convergence trends while keeping the same system parameters. When the number of microphones is one, it can completely counteract the effects of the secondary transfer function. When the number of microphones is greater than one, the secondary transfer function... The introduction of [something] alters the final convergence error at the microphone, slowing down the convergence speed in existing methods. However, the active noise reduction method for narrowband noise described in this invention achieves a convergence speed similar to that without a secondary transfer function in the early stages. At this point, stable convergence can still be ensured without adjusting system parameters.

[0035] Embodiment 2 of the present invention provides an active noise reduction device for narrowband noise, such as... Figure 4 As shown, it includes the following modules:

[0036] Data acquisition module 201 is used to acquire engine speed, initial sound field, and the control order I, number of secondary speaker units J, and number of error microphone control points required in the multi-channel system;

[0037] Execution module 202 is used to continuously execute the following steps until a preset number of iterations is reached:

[0038] Calculate the angular frequency corresponding to each control order based on the engine speed. Based on angular frequency Constructing the first cosine reference signal and the first sine reference signal According to the weighted matrix factors For the first cosine reference signal and the first sine reference signal Amplitude correction is performed to obtain the second cosine reference signal. Second sine reference signal Based on the second cosine reference signal Second sine reference signal Obtain the filtered reference signal Where i, j, k, I, J, and K are all positive integers, i = 1, 2, ..., I, j = 1, 2, ..., J, and k = 1, 2, ..., K; based on the filtered reference signal The control weights are updated and the speaker output is optimized using the error signal e(n); the optimized speaker output is then superimposed on the initial sound field.

[0039] Embodiment 3 of the present invention provides a storage medium storing program instructions, which, when executed, implement the active noise reduction method for narrowband noise as described in any of the preceding embodiments.

[0040] Embodiment 4 of the present invention provides an electronic terminal, such as Figure 5 As shown, it includes a processor and a memory, the memory storing program instructions, and the processor executing the program instructions to implement the active noise reduction method for narrowband noise as described in any of the preceding claims.

[0041] This invention can be an apparatus, method, and / or computer program product. A computer program product may include a readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of the invention.

[0042] Storage media can be tangible devices that hold and store instructions for use by instruction execution devices. Storage media can include, but are not limited to, electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination thereof. More specific examples (a non-exhaustive list) of readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination thereof.

[0043] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0044] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. An active noise reduction method of narrowband noise, characterized by, The method comprises the following steps: acquiring an engine speed, an initial sound field, an error signal e(n), and required control orders I, a number of secondary loudspeaker units J, and a number of error microphone control points K in a multi-channel system; the following steps are continuously performed until a preset number of iterations is reached: calculating an angular frequency corresponding to each control order based on the engine speed , constructing a first cosine reference signal based on the angular frequency and a first sine reference signal ;​ according to the weighting matrix factor amplitude-correcting the first cosine reference signal and the first sine reference signal to obtain a second cosine reference signal and a second sine reference signal , filtering the second cosine reference signal and the second sine reference signal to obtain a filtered reference signal ; wherein i, j, k, I, J, K are positive integers, i = 1, 2, …, I, j = 1, 2, …, J, k = 1, 2, …, K; the filtered reference signal specifically comprises: performing weighted combination on the second cosine reference signal and the second sine reference signal , and the weight coefficients are determined based on a discrete Fourier transform result of a secondary transfer function. According to the filtered reference signal and the error signal e(n) update control weights to optimize loudspeaker output; superimposing the optimized loudspeaker output on the initial sound field.

2. The method of claim 1, wherein, the weighting matrix factor is a diagonal matrix of order J x J.

3. The method of claim 1, wherein, the weighting matrix factor , where , where is the secondary transfer function value corresponding to the i-th frequency control point, the j-th channel, and the k-th microphone pair.

4. The method of claim 1, wherein, the first cosine reference signal the first sine reference signal .

5. The method of claim 1, wherein, the second cosine reference signal , the second sine reference signal .

6. The method of claim 1, wherein, The updating of the control weight comprises: updating the control weight based on the filtered reference signal and the error signal e(n) using an adaptive algorithm.

7. An active narrow-band noise reduction device, characterized in that The method comprises the following modules: a data acquisition module, configured to acquire an engine speed, an initial sound field, and required control orders I, a number of secondary loudspeaker units J, and a number of error microphone control points K in a multi-channel system; an execution module, configured to continuously perform the following steps until a preset number of iterations is reached: Calculate the angular frequency corresponding to each control order based on the engine speed. Based on angular frequency Constructing the first cosine reference signal and the first sine reference signal According to the weighted matrix factors For the first cosine reference signal and the first sine reference signal Amplitude correction is performed to obtain the second cosine reference signal. Second sine reference signal Based on the second cosine reference signal Second sine reference signal Obtain the filtered reference signal Where i, j, k, I, J, and K are all positive integers, i = 1, 2, ..., I, j = 1, 2, ..., J, and k = 1, 2, ..., K; the filtered reference signal specifically includes: the second cosine reference signal Second sine reference signal A weighted combination is performed, with the weighting coefficients determined based on the discrete Fourier transform result of the secondary transfer function; based on the filtered reference signal... The control weights are updated and the speaker output is optimized using the error signal e(n); the optimized speaker output is then superimposed on the initial sound field.

8. A storage medium storing program instructions, characterized in that, The program instructions, when executed, implement the method for active noise reduction of narrow-band noise according to any one of claims 1 to 6.

9. An electronic terminal, characterized in that The device comprises a processor and a memory, wherein the memory stores program instructions, and the processor executes the program instructions to implement the method for active noise reduction of narrow-band noise according to any one of claims 1 to 6.

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