Noise reduction methods, vehicles, readable storage media and program products

Abstract

This disclosure relates to a noise reduction method, a vehicle, a readable storage medium, and a program product, and pertains to the field of noise processing technology. The method includes: obtaining an Nth-order target audio signal based on an Nth-order target noise signal and an Nth-order target noise reduction signal for a target noise reduction region; where N is greater than or equal to 1; when the Nth-order target audio signal does not meet the noise reduction conditions, updating the Nth-order target noise reduction signal to an (N+1)th-order target noise reduction signal based on the Nth-order target audio signal, and updating the Nth-order target noise signal to an (N+1)th-order target noise signal, and obtaining an (N+1)th-order target audio signal based on the (N+1)th-order target noise signal and the (N+1)th-order target noise reduction signal; and when the (N+1)th-order target audio signal meets the noise reduction conditions, outputting the (N+1)th-order target noise reduction signal. Using the noise reduction method proposed in this disclosure can improve the noise reduction effect.

Description

Technical Field

[0001] This disclosure relates to the field of noise reduction technology, and more specifically, to a noise reduction method, a vehicle, a readable storage medium, and a program product. Background Technology

[0002] With the rapid popularization of new energy vehicles and the rapid development of intelligent technology, people's requirements for in-vehicle comfort are increasing. Traditional passive noise reduction methods can effectively suppress bird calls and high-frequency noise from mobile phones and computers, but they are difficult to alleviate low-frequency road noise such as the low rumble of other vehicles outside the vehicle. This low-frequency road noise is transmitted into the vehicle interior, negatively impacting the quiet environment inside the vehicle.

[0003] In related technologies, some noise reduction methods are used to suppress the noise transmitted into the vehicle, but their noise suppression effect is poor. Summary of the Invention

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

[0005] To achieve the above objectives, this disclosure provides a noise reduction method, comprising generating a target noise reduction signal for a target noise reduction region by performing an update operation; wherein the update operation includes:

[0006] The Nth target audio signal is obtained by combining the Nth target noise signal and the Nth target noise reduction signal in the target noise reduction region; N is greater than or equal to 1.

[0007] When the target audio signal of the Nth iteration does not meet the noise reduction condition, the target noise reduction signal of the Nth iteration is updated to the target noise reduction signal of the (N+1)th iteration based on the target audio signal of the Nth iteration, and the target noise signal of the Nth iteration is updated to the target noise signal of the (N+1)th iteration, and the target audio signal of the (N+1)th iteration is obtained based on the target noise signal of the (N+1)th iteration and the target noise reduction signal of the (N+1)th iteration.

[0008] When the target audio signal at the (N+1)th iteration satisfies the noise reduction condition, the target noise-reduced signal at the (N+1)th iteration is output.

[0009] Optionally, the noise reduction conditions include any one of the following:

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

[0011] Optionally, updating the target noise reduction signal of the Nth iteration to the target noise reduction signal of the (N+1)th iteration based on the target audio signal of the Nth iteration includes:

[0012] Based on the target audio signal of the Nth iteration, the first filter coefficients of the Nth iteration are updated to the first filter coefficients of the (N+1)th iteration; the first filter coefficients of the Nth iteration are used to process the acquired reference signal to obtain the target noise reduction signal of the Nth iteration, and the reference signal includes the environmental noise around the target noise reduction area;

[0013] The reference signal is processed using the first filter coefficients of the (N+1)th iteration to obtain the target noise reduction signal of the (N+1)th iteration.

[0014] Optionally, processing the reference signal using the first filter coefficients of the (N+1)th iteration to obtain the target noise-reduced signal of the (N+1)th iteration includes:

[0015] The reference signal is processed using the first filter coefficients of the (N+1)th iteration to obtain the first noise signal of the (N+1)th iteration output by the audio playback device;

[0016] Based on the first noise signal at the (N+1)th iteration and the first transfer function, the second noise signal of the target noise reduction region at the (N+1)th iteration is obtained; the first transfer function indicates the signal transmission path between the audio playback device and the target noise reduction region;

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

[0018] Optionally, updating the target noise signal to the (N+1)th target noise signal based on the Nth target audio signal includes:

[0019] Based on the target audio signal of the Nth iteration, the first filter coefficients of the Nth iteration are updated to the first filter coefficients of the (N+1)th iteration;

[0020] The reference signal is processed using the first filter coefficients of the (N+1)th iteration to obtain the first noise signal of the (N+1)th iteration output by the audio playback device;

[0021] The first noise signal of the N+1th time is acquired by the first audio acquisition device to obtain the third noise signal of the N+1th time.

[0022] Based on the (N+1)th third noise signal and the second transfer function, the (N+1)th target noise signal of the target noise reduction region is obtained; the second transfer function indicates the signal transmission path between the first audio acquisition device and the target noise reduction region.

[0023] Optionally, a second filter coefficient is obtained based on the first audio signal and the second audio signal; the first audio signal is the signal obtained by the first audio acquisition device after acquiring the test sound output by the audio playback device, and the second audio signal is the signal obtained by the second audio acquisition device after acquiring the test sound, wherein the second audio acquisition device is configured within the target noise reduction area;

[0024] The first audio signal is processed using the second filter coefficients to obtain the estimated third audio signal at the second audio acquisition device.

[0025] Update the second filter coefficients so that the error between the updated third audio signal and the second audio signal satisfies the 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, the step of acquiring the first noise signal at the (N+1)th time through the first audio acquisition device to obtain the third noise signal at the (N+1)th time includes:

[0028] The first noise signal of the N+1th time is acquired by the first audio acquisition device and the first noise signal of the N+1th time is obtained.

[0029] The third noise signal of the N+1th iteration is obtained based on the fourth noise signal of the N+1th iteration and the interference signal of the N+1th iteration; the interference signal of the N+1th iteration is the interference signal generated by the audio playback device on the first audio acquisition device.

[0030] Optionally, the method further includes:

[0031] The third filter coefficients are determined based on the third transfer function; the third transfer function indicates the signal transmission path between the audio playback device and the first audio acquisition device.

[0032] The interference signal obtained after filtering the first noise signal of the N+1th time through the coefficients of the third filter is determined.

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

[0034] Optionally, the area where the user's ear is located includes the headrest area inside the vehicle.

[0035] To achieve the above objectives, this disclosure provides a vehicle comprising:

[0036] A memory on which computer programs are stored;

[0037] A processor for executing the computer program in the memory to implement the steps of the noise reduction method as presented in this disclosure.

[0038] To achieve the above objectives, this disclosure provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the noise reduction method proposed in this disclosure.

[0039] To achieve the above objectives, this disclosure provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the noise reduction method proposed in this disclosure.

[0040] Through the above technical solution, 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 conditions, the target noise reduction signal can be output so that the target audio signal in the target noise reduction area can meet the noise reduction conditions and achieve a good noise reduction effect in the target noise reduction area.

[0041] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0042] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

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

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

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

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

[0047] Figure 5 This is a schematic diagram of the noise reduction area achieved by two different noise reduction methods according to an exemplary embodiment.

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

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

[0050] Figure 8 It is a block diagram of a vehicle proposed according to an exemplary embodiment. Specific Embodiments

[0051] The following will describe the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining and illustrating the present disclosure, and are not used to limit the present disclosure.

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

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

[0054] The target noise reduction area is a specified area that the embodiments of the present disclosure strive to reduce noise. The target noise reduction area is a virtual area where no noise reduction device is set, and the target noise reduction area can be the area where the human ear is located.

[0055] For example, the area where the human ear is located includes the headrest area inside the vehicle. The embodiments of the present disclosure can perform targeted noise reduction on the headrest area inside the vehicle, so that the human ear of the user located in the headrest area can experience a quiet in-vehicle environment. Further, the target noise reduction area can be at the eardrum of the human ear of the user located in the headrest area.

[0056] Another example is that the area where the human ear is located includes the rest area inside the room. The rest area includes a sofa area, a bed area, an office location area, etc. The embodiments of the present disclosure can perform targeted noise reduction on the rest area inside the room, so that the user located in the rest area can experience a quiet indoor environment. Further, the target noise reduction area can be at the eardrum of the human ear of the user located in the rest area.

[0057] The target noise signal is the noise signal transmitted to the target noise reduction area after the environmental noise outside the target noise reduction area is transmitted. The noise signal contains environmental noises such as road noise, engine noise, and tire noise outside the target noise reduction area, and the noise signal will change according to the change of the environment where 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 that is transmitted to the target noise reduction area to cancel the target noise signal in the target noise reduction area. At the same moment, the phase of the target noise reduction signal 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, please refer to 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 phases of the target noise signal and the target noise reduction signal are opposite, so the two 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 Nth target noise reduction signal.

[0062] It can be understood that the target audio signal is the residual noise signal after the target noise signal in the target noise reduction area is canceled by the target noise reduction signal. Then the Nth target audio signal is the residual noise signal after the Nth target noise signal is canceled by the Nth target noise reduction signal.

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

[0064] The target noise reduction signal and the target noise signal can be continuously updated with the goal of making the target audio signal meet the noise reduction condition, and then the target audio signal can be continuously updated.

[0065] Exemplarily, when the target audio signal at the Nth time does not meet the noise reduction condition, it indicates that the target audio signal generated in the target noise reduction area is still relatively large, and the noise in the target noise reduction area is still relatively large. Therefore, step S20 can be repeatedly executed. According to the target audio signal at the Nth time, the target noise reduction signal at the Nth time is updated to the target noise reduction signal at the (N + 1)th time, and the target noise signal at the Nth time is updated to the target noise signal at the (N + 1)th time, so as to continue to obtain the target audio signal at the (N + 1)th time based on the updated target noise signal at the (N + 1)th time and the updated target noise reduction signal at the (N + 1)th time until the target audio signal at the (N + 1)th time meets the noise reduction condition.

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

[0067] When the target audio signal meets the noise reduction condition, it indicates that the target audio signal in the target noise reduction area has met the noise reduction requirement, and can ensure a quiet environment in the target noise reduction area. The noise reduction condition includes any one of the following: the target audio signal at the (N + 1)th time is less than a preset value, the number of update operations reaches a preset number, and the target audio signal cannot continue to become smaller.

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

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

[0070] Among them, the noise coefficient is used to indicate the noise level of the target audio signal.

[0071] In step S30, when the target audio signal at the (N + 1)th time meets the noise reduction condition, the target noise reduction signal at the (N + 1)th time is output.

[0072] In the related art, the road noise active control technology (Road Noise Cancellation, RNC) can be adopted. In the road noise active control technology, an error microphone is used, and the error microphone can shield external low-frequency road noise, ensuring that the low-frequency road noise at the position of the error microphone is relatively small.

[0073] If the error microphone is set at the user's ear, it will be unfavorable for the user's head movement and reduce the user experience. If the error microphone is set at a position inside the vehicle far from the user's ear, the noise reduction area of the error microphone will be far from the user's ear, and the area near the user's ear cannot be noise-reduced. 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, so the user's ear near the headrest cannot be noise-reduced, 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 cancelled by the target noise reduction signal can meet the noise reduction condition and meet the noise reduction requirement. In this way, the noise brought by the target audio signal heard by the user in the target noise reduction area is small.

[0075] On the one hand, it can specifically perform noise reduction on 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 noise-reduced, and its noise reduction effect is better. On the other hand, in the target noise reduction area, it is not necessary to additionally configure an error microphone to achieve noise reduction in the target noise reduction area, avoiding the influence of the additionally configured error microphone on the movement of the user's head and improving the user experience. For example, please refer to Figure 5 As shown in Figure a in, in the related art, the error microphone is set at a position near the user's ear, which limits the movement range of the user's head. In the embodiment of the present disclosure, please refer to Figure 5 As shown in Figure b in, the first audio collection device can be set at a position far from the user's ear, and there is a target noise reduction area at the user's ear. No hardware device is configured on this target noise reduction area, which is a virtual area. Therefore, when the user's ear is located in this target noise reduction area, the user can move freely without restricting the movement range of the user's head.

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

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

[0078] The first filter coefficients of the Nth iteration are used to filter the acquired 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 and tire noise outside the vehicle. These reference signals indicate the ambient noise outside the target noise reduction area.

[0079] Optionally, updating the first filter coefficients of the Nth iteration to obtain the first filter coefficients of the N+1th iteration includes: obtaining the first filter coefficients of the N+1th iteration based on the first filter coefficients of the Nth iteration, the target audio signal of the Nth iteration, and the fifth noise signal.

[0080] For example, we can first calculate the product of the convergence step size, the fifth noise signal, and the target audio signal obtained in the Nth iteration, and then subtract this product from the first filter coefficients obtained in the Nth iteration to obtain the first filter coefficients in the (N+1)th iteration. The calculation formula is as follows:

[0081]

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

[0083] The fifth noise signal is obtained based on the first transfer function and the reference signal. For example, please refer to... Figure 2 and Figure 3 As shown, the convolution of the first transfer function with the reference signal can be used as the fifth noise signal:

[0084]

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

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

[0087] The first filter coefficients of the (N+1)th iteration are used to process the acquired reference signal to obtain the target noise reduction signal of the (N+1)th iteration. The reference signal includes the environmental noise around the target noise reduction area.

[0088] Optionally, the reference signal is processed using the first filter coefficients of the (N+1)th iteration to obtain the target noise-reduced signal of the (N+1)th iteration, including the following sub-steps:

[0089] Sub-step A1: The reference signal is processed using the first filter coefficients of the (N+1)th iteration to obtain the first noise signal of the (N+1)th iteration output by the audio playback device.

[0090] The first filter coefficients are used to filter the acquired reference signal to obtain the first noise signal input to the audio playback device, which then plays and outputs the first noise signal.

[0091] In some scenarios, please refer to Figure 4 As shown, the vehicle interior is equipped with an accelerometer, an audio playback device, and a first audio acquisition device. The accelerometer acquires a reference signal, which is then filtered using a first filter coefficient to obtain a first noise signal. The audio playback device then plays the filtered first noise signal. This processed first noise signal is transmitted to the headrest area, a target noise reduction region. Simultaneously, the first noise signal output by the audio playback device is also directly transmitted to the target noise reduction region. A controller inverts the noise signal arriving within the target noise reduction region 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 region, leaving a residual target audio signal. This target audio signal is relatively small, ensuring a quiet environment within the target noise reduction region. The audio playback device can be a speaker.

[0092] Furthermore, the first audio acquisition device can be a physical microphone. Since the first audio acquisition device can be placed in a non-target noise reduction area, such as the A-pillar and B-pillar inside the vehicle, the error microphone that was originally placed in the target noise reduction area is moved to other places in the vehicle. This is beneficial to the hardware layout inside the vehicle. At the same time, placing the target noise reduction area at the eardrum can further improve the noise reduction effect.

[0093] Optionally, please refer to Figure 2 and Figure 3 As shown, the first filter coefficients of the (N+1)th iteration can be convolved with the reference signal to obtain the first noise signal of the (N+1)th iteration. The calculation formula is as follows:

[0094]

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

[0096] Sub-step A2: Based on the first noise signal of the (N+1)th iteration and the first transfer function, obtain the second noise signal of the target noise reduction region of the (N+1)th iteration.

[0097] It can be determined that the first noise signal of the N+1th iteration, after being transmitted through the first transfer function, reaches the second noise signal of the N+1th iteration in the target noise reduction region.

[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 can be the first noise signal generated by the audio playback device being reflected and refracted by transmission media such as the vehicle interior wall, vehicle seats, and vehicle floor, and finally reaching the target noise reduction area. During this process, the vehicle interior wall, vehicle seats, and vehicle floor serve as transmission media for the first noise signal to be transmitted to the first audio acquisition device.

[0099] For the first transfer function, two audio acquisition devices can be set up in the target noise reduction area inside the vehicle or room. The second audio acquisition device acquires the test sound output by the audio playback device to obtain the second audio signal. The test sound is processed using the second filter coefficients to obtain the estimated fourth audio signal at the second audio acquisition device. The second filter coefficients are updated so that the error between the updated fourth audio signal at the second audio acquisition device and the second audio signal satisfies the convergence condition. The filter corresponding to the second filter coefficients when the error satisfies 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 used to test and obtain the first transfer function; for example, it can be white noise output by an audio playback device.

[0102] The error meets the convergence condition if any of the following conditions are met: the error is less than a preset value, the error no longer decreases, or the number of times the coefficients of the second filter are updated reaches a preset number.

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

[0104] Optionally, please refer to Figure 2 and Figure 3As shown, the first noise signal of the (N+1)th iteration can be convolved with the first transfer function to obtain the second noise signal of the (N+1)th iteration in the target noise reduction region. The calculation formula is as follows:

[0105]

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

[0107] Sub-step A3 involves inverting the second noise signal of the (N+1)th iteration to obtain the target noise reduction signal of the (N+1)th iteration.

[0108] The second noise signal for the N+1th iteration is obtained using formulas (4) and (5). Then, the second noise signal of the (N+1)th iteration can be... After inversion, the target noise reduction signal of the N+1th iteration is obtained; then the sum of the target noise reduction signal of the N+1th iteration and the target noise signal of the N+1th iteration is used as the target audio signal of the N+1th iteration, thus obtaining the target audio signal of the N+1th iteration remaining after the target noise signal of the N+1th iteration is canceled by the target noise reduction signal of the N+1th iteration.

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

[0110] The above technical solution allows for the initial acquisition of a first noise signal output by the audio playback device, followed by the determination of a second noise signal that evolves upon reaching the target noise reduction area. Finally, the second noise signal is inverted to obtain the target noise-reduced signal. During this process, since the audio playback device outputs ambient noise from the area surrounding the target noise reduction region, the target noise-reduced signal obtained by inverting the ambient noise transmitted to the target noise reduction region can eliminate this ambient noise, leaving only a small amount of noise or even none at all. Therefore, users located within the target noise reduction region experience less noise.

[0111] Furthermore, by updating the first filter coefficients to update the first noise signal, 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 related to the second noise signal is updated. Thus, by continuously updating the first filter coefficients, the difference between the final target noise reduction signal and the target noise signal gradually decreases, resulting in a continuous reduction in the final output target audio signal.

[0112] The following describes an exemplary scheme for obtaining the target noise signal of the target noise reduction region based on the target audio signal in step S20 above, when the target audio signal in the Nth iteration does not meet the noise reduction conditions. The scheme includes the following steps:

[0113] In step S23, the first filter coefficients of the Nth time are updated to the first filter coefficients of the N+1th time based on the target audio signal of the Nth time.

[0114] This step can refer to the exemplary solution of step S21 above, and will not be repeated here.

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

[0116] This step can refer to the exemplary solution of step S22 above, and will not be repeated here.

[0117] In step S25, the first noise signal of the N+1th time is acquired by the first audio acquisition device to obtain the third noise signal of the N+1th time.

[0118] The (N+1)th noise signal is the noise signal generated by the external environment that reaches the first audio acquisition device.

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

[0120] The (N+1)th fourth noise signal is the first noise signal output by the audio playback device, which is transmitted through a medium such as inside a vehicle or room to the first audio acquisition device, and is then collected by the first audio acquisition device. This fourth noise signal includes not only the first noise signal output by the audio playback device, but also the interference signal emitted by the audio playback device, which is transmitted through a medium such as inside a vehicle or room and reaches the first audio acquisition device.

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

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

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

[0124] Please refer to Figure 2 and Figure 3 As shown, the convolution between the first noise signal and the third transfer function in the (N+1)th iteration can be used as the interference signal, and its calculation formula is as follows:

[0125]

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

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

[0128]

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

[0130] As can be seen, the interference signal of the N+1th iteration can be subtracted from the fourth noise signal of the N+1th iteration to obtain the third noise signal of the N+1th iteration without the interference signal.

[0131] By removing the interference signal generated by the audio playback device on the first audio acquisition device from the fourth noise signal acquired by the first audio acquisition device, a clean third noise signal is obtained at the first audio acquisition device. This ensures that the target noise signal at the target noise reduction area is accurate after the subsequent third noise signal is transmitted through the first audio acquisition device to the target noise reduction area and is not affected by the interference signal. The corresponding target noise reduction signal can then more accurately eliminate the target noise signal, resulting in a smaller residual target audio signal and providing users with a quieter in-car or indoor environment.

[0132] The third transfer function includes the signal transmission path of the first noise signal between the audio playback device and the first audio acquisition device. Taking a vehicle as an example, the transmission path included in the third transfer function can be the first noise signal generated by the audio playback device being reflected and refracted by transmission media such as the vehicle interior wall, vehicle seats, and vehicle floor, and finally reaching the first audio acquisition device. The vehicle interior wall, vehicle seats, and vehicle floor serve as the transmission medium for the first noise signal to be transmitted to the first audio acquisition 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 is processed using the second filter coefficients to obtain the estimated fifth audio signal at the first audio acquisition device; the second filter coefficients are updated so that the error between the updated fifth audio signal at the first audio acquisition device and the first audio signal satisfies the convergence condition, and the filter corresponding to the second filter coefficients when the error satisfies the convergence condition is used as the third transfer function.

[0134] When the error between the fifth audio signal and the first 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 first audio acquisition device.

[0135] In step S26, the target noise signal of the target noise reduction region is obtained based on the third noise signal of the N+1th iteration and the second transfer function.

[0136] Alternatively, the convolution between the (N+1)th noise signal and the second transfer function can be used as the (N+1)th target noise signal, and its calculation formula is as follows:

[0137]

[0138] In formula (8), It is the (N+1)th target noise signal in the target noise reduction region; It is the second transfer function between the location of the first audio acquisition device and the location of the second audio acquisition device; It is the N+1th noise signal from the first audio acquisition device.

[0139] It is understandable that after obtaining the N+1th target noise signal through formula (8) and the N+1th target noise reduction signal after inverting the second noise signal through 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 acquisition device and the target noise reduction area, where the location of the second audio acquisition 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 the first audio signal output by the first audio acquisition device being reflected and refracted by transmission media such as the vehicle interior wall, vehicle seats, and vehicle floor before finally reaching the second audio acquisition device. The vehicle interior wall, vehicle seats, and vehicle floor serve as transmission media for the first audio signal to be transmitted to the second audio acquisition device.

[0141] Optionally, determining the second transfer function includes: obtaining second filter coefficients based on a first audio signal and a second audio signal; the first audio signal is a signal obtained by the first audio acquisition device acquiring a test sound output by the audio playback device, and the second audio signal is a signal obtained by the second audio acquisition device acquiring the test sound, wherein the second audio acquisition device is configured within the target noise reduction area; processing the first audio signal using the second filter coefficients to obtain an estimated third audio signal at the second audio acquisition device; updating the second filter coefficients so that the error between the updated third audio signal and the second audio signal satisfies the convergence condition; and using the filter corresponding to the second filter coefficients when the error satisfies 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, they obtain a first audio signal and a second audio signal, respectively. Then, the first audio signal is filtered using the second filter coefficients to obtain a third audio signal at the second audio acquisition device. The second filter coefficients are then updated to update the third audio signal. When the error between the third audio signal and the second audio signal meets the convergence condition, the filter corresponding to the second filter coefficients when the error meets 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 indicates that the filter corresponding to the second filter coefficient can reflect the actual transmission path of the audio signal from the first audio acquisition device to the second audio acquisition device.

[0144] The above scheme involves determining the first transfer function, the second transfer function, and the third transfer function. This process is achieved by using the first filter coefficients to obtain the updated first, second, and third transfer functions. The first filter coefficients obtained this time can be based on the previously obtained first filter coefficients, the first audio signal acquired by the first audio acquisition device, and the second audio signal acquired by the second audio acquisition device. The calculation formula is as follows:

[0145] ω n+1 =ω n +μe v (n)x1(n)(9)

[0146] In formula (9), ω n+1 These are the first filter coefficients obtained after the (N+1)th 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 magnitude of each update of the first filter coefficient; e v x1(n) is the second audio signal acquired by the second audio acquisition device; x1(n) is the first audio signal acquired by the first audio acquisition device.

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

[0148] Understandably, please refer to Figure 6 As shown, this scheme is divided into a first stage and a second stage. The first stage is the training stage. In the first stage, a first audio acquisition device and a second audio acquisition device can be placed inside the vehicle. The initial transfer function between the audio playback device and the first audio acquisition device is updated by updating the second filter coefficients to obtain the third transfer function. The initial transfer function between the audio playback device and the second audio acquisition device is updated to obtain the first transfer function. The initial transfer function between the first audio acquisition device and the second audio acquisition device is updated to obtain the second transfer function.

[0149] The second stage is the user application stage. Since the first, second, and third transfer functions have been obtained in the first stage, the second audio acquisition device can be removed in the second stage. A virtual target noise reduction region is used in the area where the second audio acquisition device is located. For example, the target noise reduction region might have the second audio acquisition device set up in the first stage, but the second stage would remove the second audio acquisition device. Based on the first, second, and third transfer functions obtained in the first stage, the target noise reduction signal and target noise signal arriving at the target noise reduction region are estimated in the second stage. The target noise reduction signal and target noise signal are updated by updating the first filter coefficients, 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, i.e., the target audio signal, meets the noise reduction condition, the target noise reduction signal that meets the condition is output to perform noise reduction on the target noise reduction region, thereby making the target audio signal generated by the target noise reduction region meet the noise reduction condition.

[0150] In obtaining the second transfer function, it can be calculated by comparing the cross-power spectral density at the first and second audio acquisition devices, as well as the auto-power spectral density at the first audio acquisition device. However, the second transfer function remains constant. Changes in the external environment will alter the detected first and second audio signals, leading to a change in the second transfer function. This fixed second transfer function reduces its accuracy, which in turn reduces the accuracy of the obtained target noise signal, resulting in a larger final output target audio signal.

[0151] In this embodiment, after the first and second audio signals change, the first audio signal is processed by the second filter coefficients to obtain the third audio signal. The second filter coefficients are then updated to update the obtained third audio signal, continuously bringing the third audio signal closer to the second audio signal. Only when the error between the third and second audio signals meets the convergence condition is the second filter coefficient at the convergence condition used as the second transfer function. At this point, the second transfer function adapts to the changed first and second audio signals. During this process, the second filter coefficients change with the changes in the first and second audio signals, and they adaptively adjust with changes in the external environment. Therefore, the second transfer function corresponding to the second filter coefficients also dynamically changes with changes in the external environment, improving the accuracy of the target noise signal obtained based on the accurate second transfer function. Ultimately, the target noise signal is better canceled by the target noise reduction signal, resulting in a smaller target audio signal.

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

[0153] The calculation module 710 is configured to obtain the Nth target audio signal based on the Nth target noise signal and the Nth target noise reduction signal in the target noise reduction region; N is greater than or equal to 1.

[0154] The update module 720 is configured to, when the target audio signal of the Nth time does not meet the noise reduction conditions, update the target noise reduction signal of the Nth time to the target noise reduction signal of the (N+1)th time, and update the target noise signal of the Nth time to the target noise signal of the (N+1)th time, and obtain the target audio signal of the (N+1)th time based on the target noise signal of the (N+1)th time and the target noise reduction signal of the (N+1)th time;

[0155] The convergence module 730 is configured to output the target noise-reduced signal at the (N+1)th iteration when the target audio signal satisfies the noise reduction condition.

[0156] Optionally, the noise reduction conditions include any one of the following:

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

[0158] Optionally, the update module 720 includes:

[0159] The first update submodule is configured to update the first filter coefficients of the Nth time to the first filter coefficients of the (N+1)th time based on the target audio signal of the Nth time; the first filter coefficients of the Nth time are used to process the acquired reference signal to obtain the target noise reduction signal of the Nth time, 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 first filter coefficients of the (N+1)th iteration to obtain the target noise-reduced signal of the (N+1)th iteration.

[0161] Optionally, the processing submodule includes:

[0162] The first processing submodule is configured to process the reference signal using the first filter coefficients of the (N+1)th iteration to obtain the first noise signal of the (N+1)th iteration output by the audio playback device.

[0163] The second processing submodule is configured to obtain the second noise signal of the target noise reduction region at the (N+1)th time based on the first noise signal at the (N+1)th time and the first transfer function; the first transfer function indicates the signal transmission path between the audio playback device and the target noise reduction region;

[0164] The third processing submodule is configured to invert the second noise signal of the (N+1)th iteration to obtain the target noise reduction signal of the (N+1)th iteration.

[0165] Optionally, the update module 720 includes:

[0166] The first update submodule is configured to update the first filter coefficients of the Nth time to the first filter coefficients of the N+1th time based on the target audio signal of the Nth time.

[0167] The processing submodule is configured to process the reference signal using the first filter coefficients of the (N+1)th iteration to obtain the first noise signal of the (N+1)th iteration output by the audio playback device.

[0168] The acquisition submodule is configured to acquire the first noise signal of the N+1th time through the first audio acquisition device to obtain the third noise signal of the N+1th time.

[0169] The transmission submodule is configured to obtain the target noise signal of the target noise reduction region at the (N+1)th iteration based on the third noise signal at the (N+1)th iteration and the second transfer function; the second transfer function indicates the signal transmission path between the first audio acquisition device and the target noise reduction region.

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

[0171] The second filtering calculation module is configured to obtain second filter coefficients based on the first audio signal and the second audio signal; the first audio signal is the signal obtained by the first audio acquisition device after acquiring the test sound output by the audio playback device, and the second audio signal is the signal obtained by the second audio acquisition device after acquiring the test sound, and the second audio acquisition device is configured within the target noise reduction area;

[0172] The second filtering module is configured to process the first audio signal using second filter coefficients to obtain the estimated third audio signal at the second audio acquisition device.

[0173] The second filter update module is configured to update the second filter coefficients so that the error between the updated third audio signal and the second audio signal satisfies the convergence condition.

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

[0175] Optionally, the data acquisition submodule includes:

[0176] The first acquisition submodule is configured to acquire the first noise signal of the N+1th time output by the audio playback device through the first audio acquisition device to obtain the fourth noise signal of the N+1th time.

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

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

[0179] The third filtering module is configured to determine the coefficients of the third filter based on a third transfer function; the third transfer function indicates the signal transmission path between the audio playback device and the first audio acquisition device.

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

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

[0182] Optionally, the area where the user's ear is located includes the headrest area inside the vehicle.

[0183] Figure 8 This is a schematic diagram of a vehicle according to an exemplary embodiment, the vehicle being equipped with a memory and a processor, the memory storing a computer program, and the processor executing the computer program in the memory to implement the noise reduction method proposed in this disclosure.

[0184] According to an exemplary embodiment, this disclosure also proposes a readable storage medium having a computer program stored thereon that, when executed by a processor, implements the noise reduction method proposed in this disclosure.

[0185] According to an exemplary embodiment, this disclosure also proposes a computer program product, including a computer program that, when executed by a processor, implements the noise reduction method proposed in this disclosure.

[0186] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this 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, this disclosure will not describe the various possible combinations separately.

[0188] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A noise reduction method, characterized in that, include: A target noise reduction signal for the target noise reduction region is generated by performing an update operation; wherein the update operation includes: The Nth target audio signal is obtained by combining the Nth target noise signal and the Nth target noise reduction signal in the target noise reduction region; N is greater than or equal to 1. When the target audio signal of the Nth iteration does not meet the noise reduction condition, the target noise reduction signal of the Nth iteration is updated to the target noise reduction signal of the (N+1)th iteration based on the target audio signal of the Nth iteration, and the target noise signal of the Nth iteration is updated to the target noise signal of the (N+1)th iteration, and the target audio signal of the (N+1)th iteration is obtained based on the target noise signal of the (N+1)th iteration and the target noise reduction signal of the (N+1)th iteration. When the target audio signal at the (N+1)th iteration satisfies the noise reduction condition, the target noise-reduced signal at the (N+1)th iteration is output. The process of updating the target noise signal from the Nth time to the (N+1)th time based on the target audio signal includes: Based on the target audio signal of the Nth iteration, the first filter coefficients of the Nth iteration are updated to the first filter coefficients of the (N+1)th iteration; The reference signal is processed using the first filter coefficients of the (N+1)th iteration to obtain the first noise signal of the (N+1)th iteration output by the audio playback device; The first noise signal of the N+1th time is acquired by the first audio acquisition device and the output of the audio playback device to obtain the fourth noise signal of the N+1th time. The third noise signal is obtained based on the (N+1)th fourth noise signal and the (N+1)th interference signal; the (N+1)th interference signal is the interference signal generated by the audio playback device on the first audio acquisition device. Based on the (N+1)th third noise signal and the second transfer function, the (N+1)th target noise signal of the target noise reduction region is obtained; the second transfer function indicates the signal transmission path between the first audio acquisition device and the target noise reduction region. The method further includes: The third filter coefficients are determined according to the third transfer function; the third transfer function indicates the signal transmission path between the audio playback device and the first audio acquisition device. The interference signal of the N+1th time is obtained by filtering the first noise signal of the N+1th time through the coefficients of the third filter.

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

3. The method according to claim 1, characterized in that, Based on the Nth target audio signal, update the Nth target noise reduction signal to the (N+1)th target noise reduction signal, including: Based on the target audio signal of the Nth iteration, the first filter coefficients of the Nth iteration are updated to the first filter coefficients of the (N+1)th iteration; the first filter coefficients of the Nth iteration are used to process the acquired reference signal to obtain the target noise reduction signal of the Nth iteration, and the reference signal includes the environmental noise around the target noise reduction area; The reference signal is processed using the first filter coefficients of the (N+1)th iteration to obtain the target noise reduction signal of the (N+1)th iteration.

4. The method according to claim 3, characterized in that, The step of processing the reference signal using the first filter coefficients of the (N+1)th iteration to obtain the target noise-reduced signal of the (N+1)th iteration includes: The reference signal is processed using the first filter coefficients of the (N+1)th iteration to obtain the first noise signal of the (N+1)th iteration output by the audio playback device; Based on the first noise signal at the (N+1)th iteration and the first transfer function, the second noise signal of the target noise reduction region at the (N+1)th iteration is obtained; the first transfer function indicates the signal transmission path between the audio playback device and the target noise reduction region; The second noise signal of the (N+1)th iteration is inverted to obtain the target noise reduction signal of the (N+1)th iteration.

5. The method according to claim 1, characterized in that, The method further includes: The second filter coefficients are obtained based on the first audio signal and the second audio signal; the first audio signal is the signal obtained by the first audio acquisition device after acquiring the test sound output by the audio playback device, and the second audio signal is the signal obtained by the second audio acquisition device after acquiring the test sound, and the second audio acquisition device is configured within the target noise reduction area; The first audio signal is processed using the second filter coefficients to obtain the estimated third audio signal at the second audio acquisition device. Update the second filter coefficients so that the error between the updated 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.

6. The method according to any one of claims 1 to 5, characterized in that, The target noise reduction area includes the area where the user's ear is located.

7. The method according to claim 6, characterized in that, The area where the user's ears are located includes the headrest area inside the vehicle.

8. A headrest, characterized in that, The headrest includes: A memory on which computer programs are stored; A processor for executing the computer program in the memory to implement the steps of the method as described in any one of claims 1 to 7.

9. A vehicle, characterized in that, The vehicle is equipped with a headrest as described in claim 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

11. A computer program product, characterized in that, It includes a computer program that, when executed by a processor, implements the steps of the method according to any one of claims 1 to 7.

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