Noise reduction method, vehicle, readable storage medium and program product

Abstract

The invention relates to a noise reduction method, a vehicle, a readable storage medium and a program product, and relates to the technical field of noise processing, and the method comprises the steps: obtaining an Nth target audio signal according to an Nth target noise signal and an Nth target noise reduction signal of a target noise reduction region; n is greater than or equal to 1; when the Nth target audio signal does not meet the noise reduction condition, updating the Nth target noise reduction signal to the (N + 1) th target noise reduction signal according to the Nth target audio signal, and updating the Nth target noise signal to the (N + 1) th target noise signal, obtaining an (N + 1) th target audio signal according to the (N + 1) th target noise signal and the (N + 1) th target noise reduction signal; and when the (N + 1) th target audio signal satisfies the noise reduction condition, outputting the (N + 1) th target noise reduction signal. By using the noise reduction method provided by the invention, the noise reduction effect can be improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of noise processing, and in particular, to a noise reduction method, a vehicle, a readable storage medium, and a program product. Background Art

[0002] With the rapid popularization of new energy vehicles and the rapid development of intelligence, people's requirements for in-car comfort are increasing. Traditional passive noise reduction methods can effectively suppress high-frequency noises such as bird calls, mobile phones and computers, but it is difficult to alleviate low-frequency road noises such as low roars from other vehicles outside the vehicle, which makes low-frequency road noises transmitted to the interior of the vehicle, bringing negative impacts on the quiet environment inside the vehicle.

[0003] In the related art, some noise reduction methods are used to suppress the noise transmitted to the interior of the vehicle, but the noise suppression effect is poor. Summary of the invention

[0004] The purpose of the present disclosure is to provide a noise reduction method, a vehicle, a readable storage medium and a program product to improve the noise suppression effect.

[0005] In order to achieve the above object, the present disclosure provides a noise reduction method, comprising generating a target noise reduction signal for reducing noise in a target noise reduction area by performing an update operation; wherein the update operation comprises:

[0006] Obtaining an Nth target audio signal according to an Nth target noise signal of the target noise reduction area and an Nth target noise reduction signal; N is greater than or equal to 1;

[0007] When the Nth target audio signal does not meet the noise reduction condition, updating the Nth target noise reduction signal to an N+1th target noise reduction signal according to the Nth target audio signal, and updating the Nth target noise signal to an N+1th target noise signal, and obtaining an N+1th target audio signal according to the N+1th target noise signal and the N+1th target noise reduction signal;

[0008] When the N+1th target audio signal satisfies the noise reduction condition, the N+1th target noise reduction signal is output.

[0009] Optionally, the noise reduction condition includes any one of the following:

[0010] The target audio signal for the N+1th time is less than a preset value, and the number of updates of the update operation reaches a preset number.

[0011] Optionally, updating the Nth target noise reduction signal to an N+1th target noise reduction signal according to the Nth target audio signal includes:

[0012] According to the Nth target audio signal, the Nth first filter coefficient is updated to the N+1th first filter coefficient; the Nth first filter coefficient is used to process the collected reference signal to obtain the Nth target noise reduction signal, and the reference signal includes the ambient noise around the target noise reduction area;

[0013] The reference signal is processed using the N+1th first filter coefficient to obtain the N+1th target noise reduction signal.

[0014] Optionally, the using the N+1th first filter coefficient to process the reference signal to obtain the N+1th target noise reduction signal includes:

[0015] The reference signal is processed by using the N+1th first filter coefficient to obtain an N+1th first noise signal output by the audio playback device;

[0016] Obtaining an N+1th second noise signal of the target noise reduction area according to the N+1th first noise signal and a first transfer function; the first transfer function indicates a signal transmission path between the audio playback device and the target noise reduction area;

[0017] The N+1th second noise signal is inverted to obtain the N+1th target noise reduction signal.

[0018] Optionally, updating the Nth target noise signal to an N+1th target noise signal according to the Nth target audio signal includes:

[0019] According to the Nth target audio signal, updating the Nth first filter coefficient to the N+1th first filter coefficient;

[0020] The reference signal is processed by using the N+1th first filter coefficient to obtain an N+1th first noise signal output by the audio playback device;

[0021] The first noise signal of the N+1th time is collected by the first audio collection device to obtain the third noise signal of the N+1th time;

[0022] An N+1th target noise signal of a target noise reduction area is obtained according to the N+1th third noise signal and a second transfer function; the second transfer function indicates a signal transmission path between the first audio collection device and the target noise reduction area.

[0023] Optionally, a second filter coefficient is obtained according to a first audio signal and a second audio signal; the first audio signal is a signal obtained after the first audio acquisition device acquires a test sound output by the audio playback device, the second audio signal is a signal obtained after the second audio acquisition device acquires the test sound, and the second audio acquisition device is configured in the target noise reduction area;

[0024] Processing the first audio signal using a second filter coefficient to obtain an estimated third audio signal at the second audio acquisition device;

[0025] updating the second filter coefficient so that an error between the updated third audio signal and the second audio signal satisfies a convergence condition;

[0026] The filter corresponding to the second filter coefficient when the error satisfies the convergence condition is used as the second transfer function.

[0027] Optionally, collecting the N+1th first noise signal by a first audio collection device to obtain the N+1th third noise signal includes:

[0028] The first audio collecting device collects the N+1th first noise signal output by the audio playing device to obtain the N+1th fourth noise signal;

[0029] The N+1th third noise signal is obtained according to the N+1th fourth noise signal and the N+1th interference signal; the N+1th interference signal is an interference signal generated by the audio playback device to the first audio collection device.

[0030] Optionally, the method further comprises:

[0031] Determine a third filter coefficient according to a third transfer function; the third transfer function indicates a signal transmission path between the audio playback device and the first audio acquisition device;

[0032] Determine the N+1th interference signal obtained after the N+1th first noise signal is filtered by the third filter coefficient.

[0033] Optionally, the target noise reduction area includes an area where the user's ear is located.

[0034] Optionally, the area where the user's ears are located includes a headrest area in the vehicle.

[0035] In order to achieve the above object, the present disclosure provides a vehicle, comprising:

[0036] a memory having a computer program stored thereon;

[0037] A processor is used to execute the computer program in the memory to implement the steps of the noise reduction method proposed in the present disclosure.

[0038] In order to achieve the above-mentioned objective, the present disclosure provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the noise reduction method proposed in the present disclosure are implemented.

[0039] In order to achieve the above-mentioned objective, the present disclosure provides a computer program product, including a computer program, which implements the steps of the noise reduction method proposed in the present disclosure when the computer program is executed by a processor.

[0040] Through the above technical scheme, the target audio signal can be obtained by continuously updating the target noise reduction signal and the target noise signal, so that the target audio signal in the target noise reduction area can gradually become smaller. When the target audio signal in the target area meets the noise reduction condition, the target noise reduction signal can be output to enable the target audio signal in the target noise reduction area to meet the noise reduction condition, so that a good noise reduction effect can be achieved in the target noise reduction area.

[0041] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0043] Figure 1 is a flowchart of a noise reduction method according to an exemplary embodiment.

[0044] Figure 2 is a logic diagram of a noise reduction method proposed according to an exemplary embodiment.

[0045] Figure 3 is a logic diagram of a noise reduction method proposed according to an exemplary embodiment.

[0046] Figure 4 The present invention is a schematic diagram of the positions of a first audio collection device, an audio playback device and a target noise reduction area according to an exemplary embodiment.

[0047] Figure 5 It is a schematic diagram of a region denoised by two different denoising methods according to an exemplary embodiment.

[0048] Figure 6It is a control schematic diagram of the first stage and the second stage proposed according to an exemplary embodiment.

[0049] Figure 7 is a block diagram of a noise reduction device according to an exemplary embodiment.

[0050] Figure 8 is a block diagram of a vehicle according to an exemplary embodiment. DETAILED DESCRIPTION

[0051] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0052] Figure 1 is a flowchart of a noise reduction method according to an exemplary embodiment, wherein a target noise reduction signal for noise reduction in a target noise reduction area is generated by performing an update operation; wherein the update operation includes the following steps:

[0053] In step S10, an Nth target audio signal is obtained according to the Nth target noise signal of the target noise reduction area and the Nth target noise reduction signal; N is greater than or equal to 1.

[0054] The target noise reduction area is a designated area where the embodiments of the present disclosure are intended to reduce noise. The target noise reduction area is a virtual area where no noise reduction equipment is set. The target noise reduction area may be an area where human ears are located.

[0055] For example, the area where the human ear is located includes the headrest area inside the vehicle. The embodiment of the present disclosure can reduce noise in a targeted manner in the headrest area inside the vehicle, so that the user's ears located in the headrest area can experience a quiet in-vehicle environment. Furthermore, the target noise reduction area can be the eardrum of the user's ear located in the headrest area.

[0056] For another example, the area where the human ear is located includes the rest area inside the room, and the rest area includes the sofa area, the bed area, the office area, etc. The embodiment of the present disclosure can perform targeted noise reduction on the rest area inside the room, so that the user in the rest area can experience a quiet indoor environment. Furthermore, the target noise reduction area can be the eardrum of the user in the rest area.

[0057] The target noise signal is a noise signal transmitted to the target noise reduction area after the environmental noise outside the target noise reduction area is transmitted. The noise signal includes environmental noise such as road noise, engine noise, tire noise outside the target noise reduction area. The noise signal will change according to the change of the environment in which the target noise reduction area is located. The present disclosure does not limit the type of the target noise signal.

[0058] The target noise reduction signal is a noise reduction signal transmitted to the target noise reduction area to cancel the target noise signal in the target noise reduction area. The phase of the target noise reduction signal at the same time is opposite to the phase of the target noise signal, so that the target noise reduction signal can cancel the target noise signal.

[0059] Optionally, see Figure 2 and Figure 3 As shown, the sum of the Nth target noise signal and the Nth target noise reduction signal can be used as the Nth target audio signal. The target noise signal and the target noise reduction signal have opposite phases, so they can cancel each other out. The calculation formula for obtaining the target audio signal is as follows:

[0060]

[0061] In formula (1), is the Nth target audio signal; is the Nth target noise signal; is the target noise reduction signal for the Nth time.

[0062] It can be understood that the target audio signal is the noise signal remaining after the target noise signal of the target noise reduction area is offset by the target noise reduction signal. Then the Nth target audio signal is the noise signal remaining after the Nth target noise signal is offset by the Nth target noise reduction signal.

[0063] In step S20, when the Nth target audio signal does not meet the noise reduction condition, the Nth target noise reduction signal is updated to the N+1th target noise reduction signal according to the Nth target audio signal, and the Nth target noise signal is updated to the N+1th target noise signal, and the N+1th target audio signal is obtained according to the N+1th target noise signal and the N+1th target noise reduction signal.

[0064] The target audio signal may be set as a target to satisfy the noise reduction condition, so as to continuously update the target noise reduction signal and the target noise signal, and further continuously update the target audio signal.

[0065] For example, when the Nth target audio signal does not meet the noise reduction condition, it means that the target audio signal generated in the target noise reduction area is still large, and the noise in the target noise reduction area is still large. Therefore, step S20 can be repeatedly performed to update the Nth target noise reduction signal to the N+1th target noise reduction signal, and to update the Nth target noise signal to the N+1th target noise signal according to the Nth target audio signal, so as to continue to obtain the N+1th target audio signal based on the updated N+1th target noise signal and the updated N+1th target noise reduction signal, until the N+1th target audio signal meets the noise reduction condition.

[0066] Here, referring to the above formula (1), the sum of the N+1th target noise reduction signal and the N+1th target noise signal can also be used as the N+1th target audio signal.

[0067] The target audio signal meets the noise reduction condition, indicating that the target audio signal in the target noise reduction area has met the noise reduction requirements and can ensure a quiet environment in the target noise reduction area. The noise reduction condition includes any one of the following: the N+1th target audio signal is less than the preset value, the number of updates of the update operation reaches the preset number, and the target audio signal cannot continue to decrease.

[0068] Optionally, the target audio signal being less than a preset value for the N+1th time includes that a noise coefficient of the target audio signal is less than a preset value.

[0069] Optionally, the target audio signal cannot continue to decrease includes that a noise coefficient of the target audio signal is less than a preset value.

[0070] The noise factor is used to indicate the noise level of the target audio signal.

[0071] In step S30, when the N+1th target audio signal satisfies the noise reduction condition, the N+1th target noise reduction signal is output.

[0072] In the related technology, a road noise cancellation (RNC) technology may be used. An error microphone is used in the road noise cancellation technology. The error microphone can shield external low-frequency road noise and ensure that the low-frequency road noise at the location of the error microphone is small.

[0073] However, if the error microphone is set at the user's ear, it will be detrimental to the user's head movement and reduce the user's experience; if the error microphone is set inside the vehicle, away from the user's ear, the noise reduction area of ​​the error microphone is away from the user's ear, and it is impossible to reduce the noise in the area near the user's ear; if the error microphone is set inside the headrest, the error microphone inside the headrest is physically shielded by the headrest and cannot collect clear road noise signals from the outside world, thereby failing to reduce the noise of the user's ear near the headrest, and its noise suppression effect is poor.

[0074] Through the above technical solution, by continuously adjusting and updating the target noise reduction signal, the target audio signal remaining after the target noise signal in the target noise reduction area is offset by the target noise reduction signal can meet the noise reduction condition and meet the noise reduction requirement. In this way, the noise caused by the target audio signal heard by the user in the target noise reduction area is smaller.

[0075] First, it can specifically reduce noise in the target noise reduction area to ensure a quiet environment for the user in the target noise reduction area. If the target noise reduction area is near the cochlea of ​​the human ear, the area near the cochlea of ​​the human ear can be reduced, and the noise reduction effect is better. Second, it can achieve noise reduction in the target noise reduction area without the need for additional error microphones, avoiding the influence of additional error microphones on the movement of the user's head, and improving the user experience. For example, please refer to Figure 5 As shown in FIG. a of FIG. , in the related art, the error microphone is set near the user's ear, which limits the range of movement of the user's head; and in the embodiment of the present disclosure, refer to FIG. Figure 5 As shown in Figure b, the first audio acquisition device can be set at a position far away from the user's ear, and there is a target noise reduction area at the user's ear. The target noise reduction area is not configured with hardware equipment and is a virtual area. Therefore, when the user's ear is located in the target noise reduction area, it can move freely without limiting the range of movement of the user's head.

[0076] The following is an exemplary solution for updating the Nth target noise reduction signal to the N+1th target noise reduction signal according to the Nth target audio signal in the above step S20 when the Nth target audio signal does not meet the noise reduction condition, including the following steps:

[0077] In step S21, when the Nth target audio signal does not satisfy the noise reduction condition, the Nth first filter coefficient is updated to the N+1th first filter coefficient according to the Nth target audio signal.

[0078] The Nth first filter coefficient is used to filter the collected reference signal to obtain the Nth target noise reduction signal. The reference signal includes the ambient noise around the target noise reduction area. Taking a vehicle as an example, the vehicle is equipped with an acceleration sensor, which can collect reference signals such as road noise signals and tire noise outside the vehicle. These reference signals indicate the ambient noise outside the target noise reduction area.

[0079] Optionally, updating the Nth first filter coefficient to obtain the N+1th first filter coefficient includes: obtaining the N+1th first filter coefficient according to the Nth first filter coefficient, the Nth target audio signal and the fifth noise signal.

[0080] For example, the product of the convergence step length, the fifth noise signal, and the target audio signal obtained for the Nth time may be calculated first, and then the product may be subtracted from the first filter coefficient obtained for the Nth time to obtain the first filter coefficient for the N+1th time, and the calculation formula thereof is as follows:

[0081]

[0082] In formula (2), is the first filter coefficient obtained for the N+1th time, is the first filter coefficient obtained for the Nth time; μ is the convergence step size, which is the update value used for each update of the first filter coefficient, indicating the amplitude of each update of the first filter coefficient; is the Nth target audio signal; x'(n) is the fifth noise signal.

[0083] The fifth noise signal is obtained according to the first transfer function and the reference signal. Figure 2 and Figure 3 As shown, the convolution of the first transfer function and the reference signal can be used as the fifth noise signal:

[0084]

[0085] In formula (3), x'(n) is the fifth noise signal; is the first transfer function; x(n) is the reference signal.

[0086] In step S22, the reference signal is processed using the N+1th first filter coefficient to obtain the N+1th target noise reduction signal.

[0087] The N+1th first filter coefficient is used to process the collected reference signal to obtain the N+1th target noise reduction signal, and the reference signal includes the ambient noise around the target noise reduction area.

[0088] Optionally, the reference signal is processed using the N+1th first filter coefficient to obtain the N+1th target noise reduction signal, comprising the following sub-steps:

[0089] Sub-step A1: Process the reference signal using the N+1th first filter coefficient to obtain the N+1th first noise signal output by the audio playback device.

[0090] The first filter coefficient is used to filter the collected reference signal to obtain a first noise signal which is input to the audio playback device, and the audio playback device then plays and outputs the first noise signal.

[0091] In some cases, see Figure 4 As shown, the vehicle is equipped with an acceleration sensor, an audio player and a first audio acquisition device. The acceleration sensor acquires a reference signal, and then uses a first filter coefficient to filter the reference signal to obtain a first noise signal. The audio player then plays the filtered first noise signal, and the processed first noise signal is transmitted to the headrest area, which is the target noise reduction area. At the same time, the first noise signal output by the audio player is also directly transmitted to the target noise reduction area, and the noise signal reaching the target noise reduction area is inverted by the controller to obtain the target noise reduction signal. The target noise reduction signal and the target noise signal cancel each other out within the target noise reduction area, thereby leaving a target audio signal. The target audio signal is relatively small, ensuring a quiet environment in the target noise reduction area. The audio player can be a speaker.

[0092] Furthermore, the first audio collection device may be a physical microphone. Since the first audio collection device may be arranged in a non-target noise reduction area, such as the A-pillar and the B-pillar in the vehicle, the error microphone originally arranged in the target noise reduction area is transferred to other places in the vehicle, which is beneficial to the hardware layout inside the vehicle. At the same time, setting the target noise reduction area at the eardrum of the human ear can further enhance the noise reduction effect.

[0093] Optionally, see Figure 2 and Figure 3 As shown, the N+1th first filter coefficient can be convolved with the reference signal to obtain the N+1th first noise signal, which is calculated as follows:

[0094]

[0095] In formula (4), y(n+1) is the first noise signal output by the audio playback device for the N+1th time; x(n) is the reference signal collected; is the first filter coefficient of the N+1th order.

[0096] Sub-step A2: obtaining the N+1th second noise signal of the target noise reduction area according to the N+1th first noise signal and the first transfer function.

[0097] It can be determined that after the N+1th first noise signal is transferred through the first transfer function, the N+1th second noise signal reaches the target noise reduction area.

[0098] The first transfer function indicates the signal transmission path of the first noise signal between the audio playback device and the target noise reduction area. Taking a vehicle as an example, the signal transmission path included in the first transfer function may be that the first noise signal generated by the audio playback device passes through the reflection and refraction of transmission media such as the vehicle inner wall, vehicle seat, and vehicle ground in the vehicle, and finally reaches the target noise reduction area. During this period, the vehicle inner wall, vehicle seat, vehicle ground, etc. serve as the transmission medium for transmitting the first noise signal to the first audio acquisition device.

[0099] For the first transfer function, two audio acquisition devices can be set on the target noise reduction area inside the vehicle or the room, and the second audio acquisition device acquires the test sound output by the audio playback device to obtain a second audio signal; the test sound is processed using the second filter coefficient to obtain an estimated fourth audio signal at the second audio acquisition device; the second filter coefficient is updated so that the error between the fourth audio signal at the updated second audio acquisition device and the second audio signal meets the convergence condition, and the filter corresponding to the second filter coefficient when the error meets the convergence condition is used as the first transfer function.

[0100] When the error between the fourth audio signal and the second audio signal meets the convergence condition, it indicates that the filter corresponding to the second filter coefficient can reflect the actual transmission path of the audio signal from the audio playback device to the second audio acquisition device.

[0101] The test sound is a test sound used to test and obtain the first transfer function, and may be, for example, white noise output by an audio playback device.

[0102] The error satisfies the convergence condition including any one of the following: the error is less than a preset value, the error does not continue to decrease, and the number of updates to the second filter coefficient reaches a preset number.

[0103] The (N+1)th second noise signal is a noise signal after the estimated (N+1)th first noise signal reaches the target noise reduction area through the transfer of the first transfer function.

[0104] Optionally, see Figure 2 and Figure 3As shown, the N+1th first noise signal and the first transfer function may be convolved to obtain the N+1th second noise signal in the target noise reduction area, and the calculation formula thereof is as follows:

[0105]

[0106] In formula (5), is the second noise signal of the N+1th time; is the first transfer function between the audio playback device and the target noise reduction area; y(n+1) is the N+1th first noise signal output by the audio playback device.

[0107] Sub-step A3: performing inversion processing on the N+1th second noise signal to obtain the N+1th target noise reduction signal.

[0108] By using formula (4) and formula (5), we can get the second noise signal of the N+1th order: Afterwards, the second noise signal of the N+1th time can be After inversion, the N+1th target noise reduction signal is obtained; then the sum of the N+1th target noise reduction signal and the N+1th target noise signal is taken as the N+1th target audio signal, thereby obtaining the N+1th target audio signal remaining after the N+1th target noise signal is offset by the N+1th target noise reduction signal.

[0109] The inversion processing of the second noise signal includes: inverting the phase of the second noise signal at different times to obtain a target noise reduction signal with a phase opposite to that of the second noise signal.

[0110] Through the above technical solution, the first noise signal output by the audio playback device can be obtained first, and the second noise signal evolved after the first noise signal reaches the target noise reduction area can be determined, and finally the second noise signal is inverted to obtain the target noise reduction signal. In this process, since the audio playback device outputs the environmental noise around the target noise reduction area, the target noise reduction signal obtained by inverting the environmental noise transmitted to the target noise reduction area can eliminate the environmental noise, so that a small part of the noise remains or even no noise remains, so the noise heard by users in the target noise reduction area is relatively small.

[0111] Furthermore, the first noise signal is updated by updating the first filter coefficient, and then the second noise signal after the first noise signal is transmitted to the target noise reduction area is updated. After the second noise signal is updated, the target noise reduction signal that is inversely phase with the second noise signal is updated. In this way, by continuously updating the first filter coefficient, the gap between the target noise reduction signal and the target road noise signal is gradually reduced, so that the target audio signal finally outputted is continuously reduced.

[0112] The following is an exemplary solution for obtaining a target noise signal of a target noise reduction area according to the Nth target audio signal when the Nth target audio signal does not meet the noise reduction condition in the above step S20, including the following steps:

[0113] In step S23, according to the Nth target audio signal, the Nth first filter coefficient is updated to the N+1th first filter coefficient.

[0114] This step may refer to the exemplary solution of step S21 above, which will not be described in detail here.

[0115] In step S24, the reference signal is processed using the N+1th first filter coefficient to obtain the N+1th first noise signal output by the audio playback device.

[0116] This step may refer to the exemplary solution of step S22 above, which will not be described in detail here.

[0117] In step S25, the N+1th first noise signal is collected by a first audio collection device to obtain an N+1th third noise signal.

[0118] The third noise signal of the N+1th time is a noise signal generated by the external environment and reaching the first audio collection device.

[0119] Optionally, obtaining the N+1th third noise signal includes: acquiring the N+1th first noise signal output by the audio playback device through the first audio acquisition device to obtain the N+1th fourth noise signal; obtaining the N+1th third noise signal according to the N+1th fourth noise signal and the N+1th interference signal; the N+1th interference signal is an interference signal generated by the audio playback device to the first audio acquisition device.

[0120] The fourth noise signal of the N+1th time is a noise signal collected by the first audio collection device after the first noise signal is output by the audio playback device and transmitted through a medium such as the interior of a vehicle or the interior of a room to the first audio collection device. The fourth noise signal includes not only the first noise signal output by the audio playback device, but also an interference signal of the interference sound emitted by the audio playback device after being transmitted through a medium such as the interior of a vehicle or the interior of a room and reaching the first audio collection device.

[0121] Among them, the interference signal is a signal generated by factors such as electromagnetic interference generated by the audio playback device and the noise of the audio playback device itself during the process of the audio playback device playing the first noise signal. These interference signals are not reference signals generated by the external environment such as the road noise signal and tire noise signal outside the vehicle. Therefore, it is necessary to remove this part of the interference signal from the fourth noise signal to obtain a clean third noise signal generated by the external environment and reaching the first audio acquisition device.

[0122] Optionally, obtaining the interference signal includes: determining a third filter coefficient according to a third transfer function; and determining the N+1th interference signal obtained after filtering the N+1th first noise signal by the third filter coefficient. The third transfer function indicates a signal transmission path between the audio playback device and the first audio acquisition device.

[0123] Therein, the coefficients of the third transfer function are third filter coefficients.

[0124] Among them, see Figure 2 and Figure 3 As shown, the convolution between the N+1th first noise signal and the third transfer function can be used as the interference signal, and its calculation formula is as follows:

[0125]

[0126] In formula (6), is the N+1th interference signal generated by the audio playback device to the first audio collection device; is the third transfer function between the audio playback device and the first audio device; y(n+1) is the N+1th first noise signal output by the audio playback device.

[0127] After obtaining the N+1th interference signal, the N+1th interference signal and the N+1th fourth noise signal may be input into the following formula to obtain the N+1th third noise signal:

[0128]

[0129] In formula (7), is the third noise signal of the N+1th order at the first audio acquisition device; p (n+1) is the N+1th fourth noise signal at the first audio collection device; It is the N+1th interference signal.

[0130] It can be seen that the N+1th interference signal can be subtracted from the N+1th fourth noise signal to obtain the N+1th third noise signal that does not contain the interference signal.

[0131] By removing the interference signal generated by the audio playback device to the first audio collection device from the fourth noise signal collected by the first audio collection device, a clean third noise signal at the first audio collection device is obtained. This allows the target noise signal that arrives at the target noise reduction area after the subsequent third noise signal is transmitted to the target noise reduction area through the first audio collection device to be accurate and not affected by the interference signal. The corresponding target noise reduction signal can more accurately eliminate the target noise signal, so that the residual target audio signal will be smaller, thereby providing the user with a quieter in-car environment or in-room environment.

[0132] The third transfer function includes a signal transmission path of the first noise signal between the audio playback device and the first audio collection device. Taking a vehicle as an example, the transmission path included in the third transfer function may be that the first noise signal generated by the audio playback device passes through the reflection and refraction of transmission media such as the vehicle inner wall, vehicle seat, and vehicle ground in the vehicle, and finally reaches the first audio collection device, and the vehicle inner wall, vehicle seat, vehicle ground, etc. during the process serve as a transmission medium for transmitting the first noise signal to the first audio collection device.

[0133] For the third transfer function, the audio playback device can output a test sound, and the first audio acquisition device can acquire the test sound output by the audio playback device to obtain a first audio signal; the test sound can be processed using the second filter coefficient to obtain an estimated fifth audio signal at the first audio acquisition device; the second filter coefficient can be updated so that the error between the updated fifth audio signal at the first audio acquisition device and the first audio signal meets the convergence condition, and the filter corresponding to the second filter coefficient when the error meets the convergence condition is used as the third transfer function.

[0134] When the error between the fifth audio signal and the first audio signal satisfies the convergence condition, it indicates that the filter corresponding to the second filter coefficient can reflect the actual transmission path of the audio signal from the audio playback device to the first audio acquisition device.

[0135] In step S26, an N+1th target noise signal of the target noise reduction area is obtained according to the N+1th third noise signal and the second transfer function.

[0136] Optionally, the convolution between the third noise signal of the N+1th time and the second transfer function may be used as the target noise signal of the N+1th time, and the calculation formula thereof is as follows:

[0137]

[0138] In formula (8), is the N+1th target noise signal in the target noise reduction area; is a second transfer function between the position of the first audio collection device and the position of the second audio collection device; is the N+1th third noise signal at the first audio collection device.

[0139] It can be understood that after the N+1th target noise signal is obtained by formula (8) and the N+1th target noise reduction signal is obtained by inverting the N+1th second noise signal by formula (5), the N+1th target noise signal and the N+1th target noise reduction signal can be input into the above formula (1) to obtain the N+1th target audio signal.

[0140] The second transfer function indicates the signal transmission path of the third noise signal between the first audio collection device and the target noise reduction area, and the location of the second audio collection device is the location of the target noise reduction area. Taking a vehicle as an example, the transmission path included in the second transfer function can be that the first audio signal output by the first audio collection device passes through the reflection and refraction of the transmission medium such as the vehicle inner wall, vehicle seat, and vehicle ground in the vehicle, and finally reaches the second audio collection device, and the vehicle inner wall, vehicle seat, vehicle ground, etc. during the period serve as the transmission medium for transmitting the first audio signal to the second audio collection device.

[0141] Optionally, determining the second transfer function includes: obtaining a second filter coefficient based on the first audio signal and the second audio signal; the first audio signal is a signal obtained after the first audio acquisition device collects a test sound output by the audio playback device, and the second audio signal is a signal obtained after the second audio acquisition device collects the test sound, and the second audio acquisition device is configured in the target noise reduction area; using the second filter coefficient to process the first audio signal to obtain an estimated third audio signal at the second audio acquisition device; updating the second filter coefficient so that the error between the updated third audio signal and the second audio signal meets a convergence condition; and using the filter corresponding to the second filter coefficient when the error meets the convergence condition as the second transfer function.

[0142] For example, after the first audio acquisition device and the second audio acquisition device acquire the test sound output by the audio playback device, a first audio signal and a second audio signal are obtained respectively; after filtering the first audio signal using the second filter coefficient, a third audio signal at the second audio acquisition device is obtained, and the second filter coefficient is updated to update the third audio signal; when the error between the third audio signal and the second audio signal satisfies the convergence condition, the filter corresponding to the second filter coefficient when the error satisfies the convergence condition is used as the second transfer function.

[0143] When the error between the third audio signal and the second audio signal meets the convergence condition, it means that the filter corresponding to the second filter coefficient can reflect the actual transmission path of the audio signal from the first audio collection device to the second audio collection device.

[0144] In the above scheme, the determination of the first transfer function, the second transfer function and the third transfer function is involved. In this process, the updated first transfer function, the second transfer function and the third transfer function are obtained through the first filter coefficient, and the first filter coefficient obtained this time can be obtained based on the first filter coefficient obtained last time, the first audio signal collected by the first audio collection device and the second audio signal collected by the second audio collection device. The calculation formula is as follows:

[0145] ω n+1 =ω n +μe v (n)x 1 (n)(9)

[0146] In formula (9), ω n+1 is the first filter coefficient obtained after the N+1th update; ω n is the first filter coefficient obtained after the Nth update; μ is the convergence step size, which is the update value used for each update of the first filter coefficient, indicating the amplitude of each update of the first filter coefficient; e v (n) is the second audio signal collected by the second audio collection device; x 1 (n) is the first audio signal collected by the first audio collection device.

[0147] It can be seen from the above formula (9) that the convergence step size and the product between the first audio signal and the second audio signal can be calculated first, and then the product is superimposed on the first filter coefficient obtained last time to obtain the first filter coefficient this time.

[0148] Understandably, see Figure 6 As shown, the scheme is divided into a first stage and a second stage. The first stage is a training stage, in which a first audio acquisition device and a second audio acquisition device can be arranged in a vehicle, and an initial transfer function between an audio playback device and the first audio acquisition device is updated by updating a second filter coefficient to obtain a third transfer function, an initial transfer function between an audio playback device and the second audio acquisition device is updated to obtain a first transfer function, and an initial transfer function between the first audio acquisition device and the second audio acquisition device is updated to obtain a second transfer function.

[0149] The second stage is the user's application stage. Since the first transfer function, the second transfer function and the third transfer function have been obtained in the first stage, the second audio acquisition device can be cancelled in the second stage, and a virtual target noise reduction area is used in the area where the second audio acquisition device is located. For example, the target noise reduction area will be set with a second audio acquisition device in the first stage, but the setting of the second audio acquisition device will be cancelled in the second stage. Based on the first transfer function, the second transfer function and the third transfer function obtained in the first stage, the target noise reduction signal and the target noise signal reaching the target noise reduction area are estimated in the second stage, and the target noise reduction signal and the target noise signal are updated by updating the first filter coefficient, so that the sum of the target noise reduction signal and the target noise signal gradually decreases. When the sum of the target noise reduction signal and the target noise signal, that is, the target audio signal meets the noise reduction condition, the target noise reduction signal that meets the condition is output to reduce the noise of the target noise reduction area, so that the target audio signal generated by the target noise reduction area meets the noise reduction condition.

[0150] In the process of obtaining the second transfer function, the second transfer function can be calculated by comparing the cross power spectrum density at the first audio collection device and the second audio collection device, and the auto power spectrum density at the first audio collection device, but the second transfer function is unchanged. Once the external environment changes, the detected first audio signal and the second audio signal will change, which will cause the second transfer function to change. The second transfer function obtained by this scheme is fixed, which will lead to a decrease in the accuracy of the second transfer function obtained in the end. The decrease in the accuracy of the second transfer function will further lead to a decrease in the accuracy of the target noise signal obtained, so that the target audio signal output in the end is larger.

[0151] In the disclosed embodiment, after the first audio signal and the second audio signal change, the first audio signal is processed by the second filter coefficient to obtain the third audio signal, and the second filter coefficient is updated to update the obtained third audio signal, so that the third audio signal is constantly close to the second audio signal. When the error between the third audio signal and the second audio signal meets the convergence condition, the second filter coefficient that meets the convergence condition will be used as the second transfer function, and the second transfer function will adapt to the changed first audio signal and the second audio signal. In this process, the second filter coefficient changes with the change of the first audio signal and the second audio signal, and the second filter coefficient will be adaptively adjusted with the change of the external environment. Then the second transfer function corresponding to the second filter coefficient will also change dynamically with the change of the external environment, so that the accuracy of the target noise signal obtained based on the accurate second transfer function can be improved, and the target noise signal will be better offset by the target noise reduction signal, so that the target audio signal obtained is smaller.

[0152] Figure 7 A noise reduction device 700 is proposed according to an exemplary embodiment. The noise reduction device 700 includes: a calculation module 710 , an update module 720 and a convergence module 730 .

[0153] The calculation module 710 is configured to obtain an Nth target audio signal according to the Nth target noise signal of the target noise reduction area and the Nth target noise reduction signal; N is greater than or equal to 1;

[0154] The updating module 720 is configured to update the Nth target noise reduction signal to the N+1th target noise reduction signal according to the Nth target audio signal when the Nth target audio signal does not meet the noise reduction condition, and update the Nth target noise signal to the N+1th target noise signal, and obtain the N+1th target audio signal according to the N+1th target noise signal and the N+1th target noise reduction signal;

[0155] The convergence module 730 is configured to output the N+1th target noise reduction signal when the N+1th target audio signal meets the noise reduction condition.

[0156] Optionally, the noise reduction condition includes any one of the following:

[0157] The target audio signal for the N+1th time is less than a preset value, and the number of updates of the update operation reaches a preset number.

[0158] Optionally, the updating module 720 includes:

[0159] A first updating submodule is configured to update the Nth first filter coefficient to the N+1th first filter coefficient according to the Nth target audio signal; the Nth first filter coefficient is used to process the collected reference signal to obtain the Nth target noise reduction signal, and the reference signal includes the ambient noise around the target noise reduction area;

[0160] The processing submodule is configured to process the reference signal using the N+1th first filter coefficient to obtain the N+1th target noise reduction signal.

[0161] Optionally, the processing submodule includes:

[0162] A first processing submodule is configured to process the reference signal using the N+1th first filter coefficient to obtain an N+1th first noise signal output by the audio playback device;

[0163] The second processing submodule is configured to obtain the N+1th second noise signal of the target noise reduction area according to the N+1th first noise signal and a first transfer function; the first transfer function indicates a signal transmission path between the audio playback device and the target noise reduction area;

[0164] The third processing submodule is configured to perform inversion processing on the N+1th second noise signal to obtain the N+1th target noise reduction signal.

[0165] Optionally, the updating module 720 includes:

[0166] A first updating submodule is configured to update the Nth first filter coefficient to the N+1th first filter coefficient according to the Nth target audio signal;

[0167] a processing submodule, configured to process the reference signal using the N+1th first filter coefficient to obtain an N+1th first noise signal output by the audio playback device;

[0168] A collection submodule is configured to collect the N+1th first noise signal through a first audio collection device to obtain an N+1th third noise signal;

[0169] The transfer submodule is configured to obtain the N+1th target noise signal of the target noise reduction area according to the N+1th third noise signal and the second transfer function; the second transfer function indicates the signal transmission path between the first audio collection device and the target noise reduction area.

[0170] Optionally, the noise reduction device 700 further includes:

[0171] a second filtering calculation module, configured to obtain a second filter coefficient according to a first audio signal and a second audio signal; the first audio signal is a signal obtained by collecting a test sound output by the audio playback device by the first audio collection device, the second audio signal is a signal obtained by collecting the test sound by the second audio collection device, and the second audio collection device is configured in the target noise reduction area;

[0172] A second filtering module is configured to process the first audio signal using a second filter coefficient to obtain an estimated third audio signal at the second audio collection device;

[0173] A second filtering update module is configured to update the second filter coefficient so that the error between the updated third audio signal and the second audio signal meets a convergence condition;

[0174] The second filtering convergence module is configured to use the filter corresponding to the second filter coefficient when the error meets the convergence condition as the second transfer function.

[0175] Optionally, the acquisition submodule includes:

[0176] A first acquisition submodule is configured to acquire the N+1th first noise signal output by the audio playback device through the first audio acquisition device to obtain an N+1th fourth noise signal;

[0177] The removal submodule is configured to obtain the N+1th third noise signal according to the N+1th fourth noise signal and the N+1th interference signal; the N+1th interference signal is an interference signal generated by the audio playback device to the first audio collection device.

[0178] Optionally, the noise reduction device 700 further includes:

[0179] A third filtering module is configured to determine a third filter coefficient according to a third transfer function; the third transfer function indicates a signal transmission path between the audio playback device and the first audio collection device;

[0180] The interference module is configured to determine the N+1th interference signal obtained after the N+1th first noise signal is filtered by the third filter coefficient.

[0181] Optionally, the target noise reduction area includes an area where the user's ear is located.

[0182] Optionally, the area where the user's ears are located includes a headrest area in the vehicle.

[0183] Figure 8 It is a schematic diagram of a vehicle proposed according to an exemplary embodiment. The vehicle is configured with a memory and a processor. The memory stores a computer program. The processor is used to execute the computer program in the memory to implement the noise reduction method proposed in the present disclosure.

[0184] According to an exemplary embodiment, the present disclosure further provides a readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the noise reduction method provided by the present disclosure is implemented.

[0185] According to an exemplary embodiment, the present disclosure further provides a computer program product, including a computer program, which implements the noise reduction method provided by the present disclosure when the computer program is executed by a processor.

[0186] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0187] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0188] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A noise reduction method, characterized in that: include: A target noise reduction signal for reducing noise in a target noise reduction area is generated by performing an update operation; wherein the update operation includes: Obtaining an Nth target audio signal according to an Nth target noise signal of the target noise reduction area and an Nth target noise reduction signal; N is greater than or equal to 1; When the Nth target audio signal does not meet the noise reduction condition, updating the Nth target noise reduction signal to an N+1th target noise reduction signal according to the Nth target audio signal, and updating the Nth target noise signal to an N+1th target noise signal, and obtaining an N+1th target audio signal according to the N+1th target noise signal and the N+1th target noise reduction signal; When the N+1th target audio signal satisfies the noise reduction condition, the N+1th target noise reduction signal is output.

2. The method according to claim 1, characterized in that: The noise reduction condition includes any one of the following: The target audio signal for the N+1th time is less than a preset value, and the number of updates of the update operation reaches a preset number.

3. The method according to claim 1, characterized in that Updating the Nth target noise reduction signal to an N+1th target noise reduction signal according to the Nth target audio signal includes: According to the Nth target audio signal, the Nth first filter coefficient is updated to the N+1th first filter coefficient; the Nth first filter coefficient is used to process the collected reference signal to obtain the Nth target noise reduction signal, and the reference signal includes the ambient noise around the target noise reduction area; The reference signal is processed using the N+1th first filter coefficient to obtain the N+1th target noise reduction signal.

4. The method according to claim 3, characterized in that The using the N+1th first filter coefficient to process the reference signal to obtain the N+1th target noise reduction signal includes: Processing the reference signal using the N+1th first filter coefficient to obtain an N+1th first noise signal output by the audio playback device; Obtaining an N+1th second noise signal of the target noise reduction area according to the N+1th first noise signal and a first transfer function; the first transfer function indicates a signal transmission path between the audio playback device and the target noise reduction area; The N+1th second noise signal is inverted to obtain the N+1th target noise reduction signal.

5. The method according to claim 1, characterized in that: Updating the Nth target noise signal to an N+1th target noise signal according to the Nth target audio signal includes: According to the Nth target audio signal, updating the Nth first filter coefficient to the N+1th first filter coefficient; The reference signal is processed using the N+1th first filter coefficient to obtain an N+1th first noise signal output by the audio playback device; The first noise signal of the N+1th time is collected by the first audio collection device to obtain the third noise signal of the N+1th time; An N+1th target noise signal of a target noise reduction area is obtained according to the N+1th third noise signal and a second transfer function; the second transfer function indicates a signal transmission path between the first audio collection device and the target noise reduction area.

6. The method according to claim 5, characterized in that The method further comprises: A second filter coefficient is obtained according to a first audio signal and a second audio signal; the first audio signal is a signal obtained by collecting a test sound output by the audio playback device by the first audio acquisition device, the second audio signal is a signal obtained by collecting the test sound by the second audio acquisition device, and the second audio acquisition device is arranged in the target noise reduction area; Processing the first audio signal using a second filter coefficient to obtain an estimated third audio signal at the second audio acquisition device; updating the second filter coefficient so that an error between the updated third audio signal and the second audio signal satisfies a convergence condition; The filter corresponding to the second filter coefficient when the error satisfies the convergence condition is used as the second transfer function.

7. The method according to claim 5, characterized in that The collecting the N+1th first noise signal by the first audio collecting device to obtain the N+1th third noise signal includes: The first audio collecting device collects the N+1th first noise signal output by the audio playing device to obtain the N+1th fourth noise signal; The N+1th third noise signal is obtained according to the N+1th fourth noise signal and the N+1th interference signal; the N+1th interference signal is an interference signal generated by the audio playback device to the first audio collection device.

8. The method according to claim 7, characterized in that The method further comprises: Determine a third filter coefficient according to a third transfer function; the third transfer function indicates a signal transmission path between the audio playback device and the first audio acquisition device; Determine the N+1th interference signal obtained after the N+1th first noise signal is filtered by the third filter coefficient.

9. The method according to any one of claims 1 to 8, characterized in that: The target noise reduction area includes an area where the user's ear is located.

10. The method according to claim 9, characterized in that The area where the user's ears are located includes a headrest area in the vehicle.

11. A headrest, characterized in that: The headrest comprises: a memory having a computer program stored thereon; A processor, configured to execute the computer program in the memory to implement the steps of the method according to any one of claims 1 to 10.

12. A vehicle, characterized in that: The vehicle is provided with the headrest according to claim 11.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 10 are implemented.

14. A computer program product, characterized in that The invention comprises a computer program, which implements the steps of the method according to any one of claims 1 to 10 when being executed by a processor.

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