Active noise reduction method and device for narrowband noise, storage medium and terminal

Abstract

The invention discloses an active noise reduction method and device for narrow-band noise, a storage medium and a terminal. The method comprises the following steps: acquiring the rotating speed of an engine, an initial sound field, an error signal, and a control order, the number of secondary loudspeaker units and the number of error microphone control points required in a multi-channel system; continuously executing the following steps until a preset number of iterations is reached: calculating an angular frequency corresponding to each control order according to the rotating speed of the engine, and constructing a first cosine reference signal and a first sine reference signal based on the angular frequency; performing amplitude correction on the first cosine reference signal and the first sine reference signal according to the weighting matrix factor to obtain a second cosine reference signal, a second sine reference signal and a filtering reference signal; according to the filtering reference signal and the error signal, updating a control weight to optimize loudspeaker output; and overlapping the optimized loudspeaker output with the initial sound field. The noise reduction effect is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of narrowband noise, and in particular to a method, device, storage medium and terminal for active noise reduction of narrowband noise. Background Art

[0002] In the active control of automobile engine order 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 MeanSquare, filtered x minimum mean square error), so that the secondary sound source produces a sound wave with a phase opposite to the primary sound source at the error microphone, thereby minimizing the sound field.

[0003] However, the reference signal amplitude constructed in the prior art is usually kept constant or has a default value of 1, which results in the system being unable to effectively track the change of the error signal; in addition, due to the introduction of the secondary transfer function The amplitude response varies significantly at different frequencies and between different channels, resulting in inconsistent responses for different speaker channels and frequencies. This necessitates adjusting the step size to ensure system convergence speed and noise reduction effectiveness. This adjustment effort increases with the number of channels. Dynamically adjusting the active noise reduction and controlling multiple frequencies requires inputting different parameters for each state and frequency, further increasing operational complexity.

[0004] Therefore, how to use effective methods to overcome the defects of existing technologies has become a technical problem that needs to be solved urgently. Summary of the Invention

[0005] The purpose of the present invention is to address the above-mentioned problems and provide a method, device, storage medium and terminal for active noise reduction of narrowband noise.

[0006] The technical solution of the present invention is: an active noise reduction method for narrowband noise, comprising the following steps: obtaining engine speed, initial sound field, error signal e(n), and the control order I, the number of secondary speaker units J, and the number of error microphone control points K required in a multi-channel system; continuously performing the following steps until a preset number of iterations is reached: calculating the angular frequency corresponding to each control order according to the engine speed; , based on the angular frequency Construct the first cosine reference signal and the first sinusoidal reference signal ; According to the weighted matrix factor The first cosine reference signal and the first sinusoidal reference signal Perform amplitude correction to obtain the second cosine reference signal and the second sinusoidal reference signal , based on the second cosine reference signal and the second sinusoidal reference signal Get the filtered reference signal ; Wherein, i, j, k, I, J, K are all positive integers, i=1,2,…,I, j=1,2,…,J, k=1,2,…,K; According to the filtering reference signal and the error signal e(n) to update the control weight to optimize the loudspeaker output; and superimpose the optimized loudspeaker output with the initial sound field.

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

[0008] As an improvement to the embodiment of the present invention, the weighted matrix factor The element Ai,j=1 / max( ),in, is 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 the embodiment of the present invention, the first cosine reference signal , the first sinusoidal reference signal .

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

[0011] As an improvement of the embodiment of the present invention, the filtering reference signal specifically includes: filtering the second cosine reference signal and the second sinusoidal 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 the embodiment of the present invention, the updating of the control weight includes: updating the control weight by adopting an adaptive algorithm based on the filtered reference signal and the error signal e(n).

[0013] To achieve one of the above-mentioned objectives of the invention, an embodiment of the present invention provides an active noise reduction device for narrowband noise, comprising the following modules: a data acquisition module for acquiring engine speed, initial sound field, and the control order I, the number of secondary speaker units J, and the number of error microphone control points K required in a multi-channel system; an execution module for continuously executing the following steps until a preset number of iterations is reached: calculating the angular frequency corresponding to each control order according to the engine speed; , based on the angular frequency Construct the first cosine reference signal and the first sinusoidal reference signal ; According to the weighted matrix factor The first cosine reference signal and the first sinusoidal reference signal Perform amplitude correction to obtain the second cosine reference signal and the second sinusoidal reference signal , based on the second cosine reference signal and the second sinusoidal reference signal Get the filtered reference signal ; Wherein, i, j, k, I, J, K are all positive integers, i=1,2,…,I, j=1,2,…,J, k=1,2,…,K; According to the filtering reference signal The error signal e(n) is used to update the control weights to optimize the loudspeaker output; and the optimized loudspeaker output is superimposed on the initial sound field.

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

[0015] To achieve one of the above-mentioned objectives of the invention, an 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 one of the above items.

[0016] An active noise reduction method, device, storage medium and terminal for narrowband noise provided by an embodiment of the present invention have the following advantages: the present invention introduces a weighted correction mechanism for the reference signal amplitude and determines the value of each element according to the secondary transfer function characteristics, so that the error convergence curves of different frequencies are consistent under the same system parameters. This solves the problem of inconsistent system responses to different speaker channels and different frequencies due to large differences in the amplitude responses of the secondary transfer function between different frequencies and channels, avoids the tedious operation of frequently adjusting parameters to adapt to different situations, greatly reduces the complexity of parameter adjustment, and greatly improves the noise reduction effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 1 is a flow chart of the active noise reduction method for narrowband noise according to the present invention; Figure 2 This is a comparison chart of the convergence curves of the active noise reduction method for narrowband noise according to the present invention and the existing method; Figure 3This is a comparison chart of the noise reduction effects of the active noise reduction method for narrowband noise according to the present invention and the existing methods; Figure 4 Schematic diagram of the structure of the active noise reduction device for narrowband noise according to the present invention; Figure 5 It is a structural schematic diagram of the electronic terminal of the present invention. DETAILED DESCRIPTION

[0018] The present invention will be described in detail below 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 changes made by those skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0019] If the present invention involves directions (for example, up, down, left, right, front, back, outside, inside, etc.) when describing, the directions involved need to be defined.

[0020] The scope of the embodiments herein includes the entire scope of the claims, and all available equivalents of the claims. Herein, the terms "first", "second", etc. are only used to distinguish one element from another, without requiring or implying any actual relationship or order between these elements. In fact, the first element can also be called the second element, and vice versa. Moreover, the terms "comprise", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that the structure, device or equipment including a series of elements includes not only those elements, but also includes other elements not clearly listed, or also includes elements inherent to such structure, device or equipment. In the absence of more restrictions, the elements limited by the statement "comprising one..." do not exclude the presence of other identical elements in the structure, device or equipment including the elements. Each embodiment is described in a progressive manner herein, and each embodiment focuses on the differences from other embodiments, and the same similar parts between the embodiments can be referred to each other.

[0021] The terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like used herein to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are intended only to facilitate the description of this document and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention. In the description herein, unless otherwise specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, they can be mechanical or electrical connections, or they can be internal connections between two elements, they can be directly connected, or they can be indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0022] The first embodiment of the present invention provides an active noise reduction method for narrowband noise, such as Figure 1 As shown, the following steps are included: Step 101: Obtain the engine speed, initial sound field, error signal e(n), and the control order I, number of secondary speaker units J, and number of error microphone control points K required in the multi-channel system; In practice, the engine speed can be based on the speed sensor of the engine control system, and the current operating speed value of the engine can be obtained through the CAN bus or a dedicated signal acquisition module; the acquisition of the initial sound field requires that before the engine is running, a microphone array arranged in the vehicle or test environment and adapted to the position of the error microphone control point is used to collect the ambient noise sound field data when there is no active noise reduction intervention; the error signal e(n) is collected by the error microphone installed in the target noise reduction area; the control order I corresponds to the main order noise of the engine; the number of secondary speaker units J is set according to the size of the noise reduction space, noise distribution and control accuracy requirements, and the output reverse phase sound waves cancel the noise; the number of error microphone control points K is based on the monitoring needs of the noise reduction effect, and the microphones are reasonably arranged at noise-sensitive points and points where the sound field changes drastically, and the error signal after noise reduction is fed back in real time.

[0023] Step 102: Continue to perform the following steps until a preset number of iterations is reached: Calculate the angular frequency corresponding to each control order according to the engine speed , based on the angular frequency Construct the first cosine reference signal and the first sinusoidal reference signal ; According to the weighted matrix factor The first cosine reference signal and the first sinusoidal reference signal Perform amplitude correction to obtain the second cosine reference signal and the second sinusoidal reference signal , based on the second cosine reference signal and the second sinusoidal reference signal Get the filtered reference signal ; Wherein, i, j, k, I, J, K are all positive integers, i=1,2,…,I, j=1,2,…,J, k=1,2,…,K; According to the filtering reference signal and the error signal e(n) to update the control weight to optimize the loudspeaker output; and superimpose the optimized loudspeaker output with the initial sound field.

[0024] Here, the first cosine reference signal , the first sinusoidal reference signal , thereby generating a reverse base signal with the same frequency as the primary noise to achieve frequency matching. In order to solve the convergence imbalance of different channels caused by the difference in secondary transfer functions, the weighting matrix factor is introduced , the second cosine reference signal , the second sinusoidal reference signal Afterwards, in order to simulate the transfer characteristics of the secondary channel, the weight update is made to be more in line with the actual acoustic path according to the second cosine reference signal and the second sinusoidal reference signal Get the filtered reference signal The weighting matrix factor is a J×J diagonal matrix, , the weighting matrix factor The element Ai,j=1 / max( ),Right now in, is the secondary transfer function value corresponding to the i-th frequency control point, the j-th channel, and the k-th microphone. Reflects the transfer gain from the secondary sound source to the error microphone. The maximum value represents the portion of the secondary transfer function that has the most significant impact on noise reduction for that channel or order. Taking the reciprocal of the corrected reference signal amplitude ensures that the most significant portion of the signal converges, preventing divergence caused by excessive gain in a single channel and thus balancing multi-channel convergence. Figure 2 This is a comparison of the convergence curves of the active noise reduction method for narrowband noise according to the present 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 according to the present invention are consistent at different transfer function amplitudes and phases. It can be understood that this is conducive to maintaining system stability and achieving rapid parameter adjustment.

[0025] In this embodiment, the filtering reference signal specifically includes: filtering the second cosine reference signal and the second sinusoidal 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.

[0026] Here, the filtered reference signal ; Among them, the weight coefficient Subordinate letter The real and imaginary parts of the discrete Fourier transform can be calculated by inputting a sweep signal to each speaker-microphone channel in an anechoic chamber environment and calculating the transfer function through Fourier transform. The real and imaginary parts of .

[0027] In this embodiment, the updating of the control weight includes: updating the control weight using an adaptive algorithm based on the filtered reference signal and the error signal e(n).

[0028] 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. It minimizes the error signal power by iteratively adjusting the weights. The control weights can be based on , Update, among others, is the step size factor, which can range from 0.001 to 0.1. This range can balance the convergence speed and stability in tests with different noise intensities and channel numbers in vehicle-mounted and industrial noise reduction scenarios. The expected mean of can be calculated by the following formula , .in, The optimal weight coefficient can be obtained by offline identification, inputting standard narrowband noise in an anechoic chamber environment, collecting error signals, and fitting using the least squares method; or by constructing a secondary channel model based on identification theory and solving the optimal weight through the inverse model. Reflects the amplitude correction of different channels or frequencies; Matrix operations reflect secondary propagation functions The influence of the difference on the statistical characteristics of the error signal e(n). The active noise reduction method for narrowband noise of the present invention can adjust the output of the secondary sound source. In actual noise reduction, Figure 3 This is a comparison of the noise reduction effect of the active noise reduction method of the narrowband noise of the present invention and the existing method, showing the influence of different channel numbers and error microphone numbers on the effect at the control point. After that, the convergence characteristics of the existing method completely change. At this time, if you want to offset the influence of the transfer function, you need to readjust the system parameters. However, the active noise reduction method for narrowband noise of the present invention can still bring a stable convergence trend by keeping the same system parameters. When the number of microphones is 1, it can completely offset the influence of the secondary transfer function. When the number of microphones is greater than 1, the secondary transfer function The introduction of the secondary transfer function changes the final convergence error at the microphone, slowing the convergence speed of existing methods. However, the convergence speed of the narrowband active noise reduction method described in this invention is similar to that of a method without a secondary transfer function in the early stages. In this case, stable convergence can be ensured without adjusting system parameters.

[0029] The second embodiment of the present invention provides an active noise reduction device for narrowband noise, such as Figure 4 As shown, it includes the following modules: The data acquisition module 201 is used to obtain the engine speed, the initial sound field, and the control order I, the number of secondary speaker units J, and the number of error microphone control points K required in the multi-channel system; The execution module 202 is configured to continuously execute the following steps until a preset number of iterations is reached: Calculate the angular frequency corresponding to each control order according to the engine speed , based on the angular frequency Construct the first cosine reference signal and the first sinusoidal reference signal ; According to the weighted matrix factor The first cosine reference signal and the first sinusoidal reference signal Perform amplitude correction to obtain the second cosine reference signal and the second sinusoidal reference signal , based on the second cosine reference signal and the second sinusoidal reference signal Get the filtered reference signal ; Wherein, i, j, k, I, J, K are all positive integers, i=1,2,…,I, j=1,2,…,J, k=1,2,…,K; According to the filtering reference signal The error signal e(n) is used to update the control weights to optimize the loudspeaker output; and the optimized loudspeaker output is superimposed on the initial sound field.

[0030] A third embodiment of the present invention provides a storage medium storing program instructions, wherein the program instructions, when executed, implement the active noise reduction method for narrowband noise as described in any one of the above items.

[0031] A fourth embodiment of the present invention provides an electronic terminal, such as Figure 5 As shown, it includes a processor and a memory, the memory stores program instructions, and the processor runs the program instructions to implement the active noise reduction method for narrowband noise as described in any one of the above items.

[0032] The present invention may be an apparatus, a method and / or a computer program product. The computer program product may include a readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present invention.

[0033] A storage medium may be a tangible device that holds and stores instructions used by an instruction execution device. Storage media may include, for example, but are not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof. More specific examples (a non-exhaustive list) of readable storage media include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disc (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination thereof.

[0034] It should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation method can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0035] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for active noise reduction of narrowband noise, characterized in that: The following steps are involved: Obtain the engine speed, initial sound field, error signal e(n), and the control order I, number of secondary speaker units J, and number of error microphone control points K required in the multi-channel system; Continue to perform the following steps until the preset number of iterations is reached: Calculate the angular frequency corresponding to each control order according to the engine speed , based on the angular frequency Construct the first cosine reference signal and the first sinusoidal reference signal ; According to the weighted matrix factor The first cosine reference signal and the first sinusoidal reference signal Perform amplitude correction to obtain the second cosine reference signal and the second sinusoidal reference signal , based on the second cosine reference signal and the second sinusoidal reference signal Get the filtered reference signal ; Wherein, i, j, k, I, J, K are all positive integers, i=1,2,…,I, j=1,2,…,J, k=1,2,…,K; According to the filtered reference signal and updating the control weights to optimize the loudspeaker output using the error signal e(n); The optimized loudspeaker output is superimposed on the initial sound field.

2. The active noise reduction method for narrowband noise according to claim 1, characterized in that: The weighting matrix factor is a J×J diagonal matrix.

3. The active noise reduction method for narrowband noise according to claim 1, characterized in that: The weighting matrix factor The element Ai,j=1 / max( ),in, is the secondary transfer function value corresponding to the i-th frequency control point, the j-th channel, and the k-th microphone.

4. The active noise reduction method for narrowband noise according to claim 1, characterized in that: The first cosine reference signal , the first sinusoidal reference signal .

5. The active noise reduction method for narrowband noise according to claim 1, characterized in that: The second cosine reference signal , the second sinusoidal reference signal .

6. The active noise reduction method for narrowband noise according to claim 1, characterized in that: The filtering reference signal specifically includes: filtering the second cosine reference signal and the second sinusoidal 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.

7. The active noise reduction method for narrowband noise according to claim 1, characterized in that: The updating of the control weight includes: updating the control weight using an adaptive algorithm based on the filtered reference signal and the error signal e(n).

8. An active noise reduction device for narrowband noise, characterized in that: Includes the following modules: A data acquisition module is used to obtain the engine speed, initial sound field, and the control order I, number of secondary speaker units J, and number of error microphone control points K required in a multi-channel system; The execution module is used to continuously execute the following steps until a preset number of iterations is reached: Calculate the angular frequency corresponding to each control order according to the engine speed , based on the angular frequency Construct the first cosine reference signal and the first sinusoidal reference signal ; According to the weighted matrix factor The first cosine reference signal and the first sinusoidal reference signal Perform amplitude correction to obtain the second cosine reference signal and the second sinusoidal reference signal , based on the second cosine reference signal and the second sinusoidal reference signal Get the filtered reference signal ; Wherein, i, j, k, I, J, K are all positive integers, i=1,2,…,I, j=1,2,…,J, k=1,2,…,K; According to the filtering reference signal The error signal e(n) is used to update the control weights to optimize the loudspeaker output; and the optimized loudspeaker output is superimposed on the initial sound field.

9. A storage medium storing program instructions, characterized in that: When the program instructions are executed, the active noise reduction method for narrowband noise according to any one of claims 1 to 7 is implemented.

10. An electronic terminal, characterized in that: The method comprises 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 according to any one of claims 1 to 7.

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