Noise reduction method, device, noise reduction earphones and medium

Abstract

The present disclosure provides a noise reduction method, device, noise reduction headphones and medium, the noise reduction method comprising: obtaining a first ear canal time domain signal; performing time-frequency conversion processing on the first ear canal time domain signal to obtain an ear canal frequency domain signal; obtaining the total energy of the residual noise according to a preset weighting factor and the ear canal frequency domain signal; if the total energy of the residual noise is greater than or equal to a preset first energy threshold, selecting a target gain value from a filter gain value list, and then adjusting the noise reduction filter according to the target gain value; based on the adjusted noise reduction filter, performing noise reduction filtering on the first environment time domain signal, and playing an active noise reduction signal by a speaker. In the present disclosure, by obtaining the total energy of the residual noise and selecting the target gain value from the filter gain value list, the active noise reduction effect is compensated to solve the problem of decreased active noise reduction effect caused by sound leakage, improve the noise reduction effect of the audio playback device, and enhance the user's auditory experience.

Description

Technical Field

[0001] The present disclosure relates to the technical field of sound processing, and in particular to a noise reduction method, device, noise reduction earphone and medium. Background Art

[0002] Active Noise Cancellation (ANC) technology is a technology that generates a sound signal with the same energy as the noise but opposite phase to the noise, causing the sound signal to interfere with the noise source and achieve sound wave cancellation. Active noise cancellation technology is widely used in multimedia fields with audio playback functions such as headphones, car speaker systems, and smart homes.

[0003] Currently, after users wear headphones for a long time, a gap is created between the headphones and the ear canal, and the fit between the headphones and the ears decreases, resulting in poor active noise reduction effect. Summary of the invention

[0004] In order to overcome the problems existing in the related art, the present disclosure provides a noise reduction method, device, noise reduction headphones and medium.

[0005] According to a first aspect of the present disclosure, a noise reduction method is provided, which is applied to headphones. The noise reduction method includes:

[0006] Acquire a first ear canal time domain signal, wherein the first ear canal time domain signal refers to a sound wave signal in the ear canal represented by a time domain representation;

[0007] Performing time-frequency conversion processing on the first ear canal time domain signal to obtain an ear canal frequency domain signal corresponding to the first ear canal time domain signal, wherein the ear canal frequency domain signal refers to a sound wave signal in the ear canal represented by a frequency domain representation;

[0008] Obtaining the total energy of residual noise according to a preset weighting factor and the ear canal frequency domain signal, wherein the residual noise refers to a predicted sound wave signal heard by a human ear;

[0009] If the total energy of the residual noise is greater than or equal to a preset first energy threshold, based on a pre-stored filter gain value list, selecting one of a plurality of filter gain values ​​in the filter gain value list as a target gain value, wherein the target gain value can make the total energy of the residual noise less than the first energy threshold;

[0010] Adjusting the gain value of the preset noise reduction filter to the target gain value;

[0011] Based on the adjusted noise reduction filter, performing noise reduction filtering on the first environmental time domain signal to obtain an active noise reduction signal, wherein the first environmental time domain signal refers to a sound wave signal in the environment around the earphone represented in a time domain representation manner, and the active noise reduction signal is used to cancel the noise;

[0012] The active noise reduction signal is sent to a speaker so that the speaker plays the active noise reduction signal.

[0013] Optionally, performing time-frequency conversion processing on the first ear canal time domain signal to obtain an ear canal frequency domain signal corresponding to the first ear canal time domain signal includes:

[0014] Performing windowing processing on the first ear canal time domain signal to obtain multiple frames of first ear canal sub-signals, wherein each window of the windowing processing includes n frequency points, and the first ear canal sub-signal refers to the sound wave signal in each window represented by a time domain representation;

[0015] Based on the window function used in the windowing process, time-frequency conversion is performed on each frame of the first ear canal sub-signal to obtain the ear canal frequency domain signal.

[0016] Optionally, obtaining the total energy of the residual noise according to a preset weighting factor and the ear canal frequency domain signal includes:

[0017] Obtaining an average energy value of the kth frequency point in the spectrum of the first ear canal sub-signal of each frame, wherein the spectrum refers to the frequency spectrum of the sound wave signal expressed in the frequency domain after the time-frequency conversion, and the spectrum includes multiple frequency points;

[0018] Determining the energy value of the kth frequency point according to the signal sampling rate of the first auditory canal time domain signal and the window length N when performing the windowing process, wherein the window length N refers to the number of signal frequency points contained in each window when performing the windowing process;

[0019] Determining a target weighting factor according to the preset weighting factor and the energy value of the kth frequency point;

[0020] The product of the target weighting factor and the average energy value of the k-th frequency point is used as the weighted energy value of the k-th frequency point;

[0021] The weighted energy values ​​of each frequency point in the spectrum are summed to obtain the total energy of the residual noise.

[0022] Optionally, the selecting, based on a pre-stored filter gain value list, one of a plurality of filter gain values ​​in the filter gain value list as a target gain value comprises:

[0023] The pre-stored filter gain value list includes a plurality of filter gain values ​​set in order from small to large, and the target gain value is selected from the plurality of filter gain values ​​in a traversal manner;

[0024] During the traversal process, if the selected target gain value makes the total energy of the residual noise less than the first energy threshold, then the traversal is stopped;

[0025] If, after traversing each filter gain value in the pre-stored filter gain value list, the total energy of the residual noise corresponding to each filter gain value is greater than or equal to the first energy threshold, then, from the total energies of the multiple residual noises corresponding to the multiple filter gain values, the filter gain value corresponding to the minimum value of the total energies of the multiple residual noises is selected as the target gain value.

[0026] Optionally, before performing time-frequency conversion processing on the first auditory canal time domain signal, the method further includes:

[0027] Acquire a loudspeaker reference signal, wherein the loudspeaker reference signal refers to a sound wave signal played by a loudspeaker;

[0028] Calculating the total energy of the speaker reference signal, wherein the speaker reference signal includes multiple frequency points, and the total energy of the speaker reference signal refers to the sum of the energies of each frequency point in the speaker reference signal;

[0029] If the total energy of the loudspeaker reference signal is less than or equal to a preset second energy threshold, time-frequency conversion processing is performed on the first ear canal time domain signal.

[0030] Optionally, before performing time-frequency conversion processing on the first auditory canal time domain signal, the method further includes:

[0031] Acquire a second environment time domain signal, wherein the second environment time domain signal refers to a sound wave signal in the environment surrounding the earphone collected within a preset time before collecting the first environment time domain signal;

[0032] Calculating the total energy of the second environment time domain signal, wherein the second environment time domain signal includes multiple frequency points, and the total energy of the second environment time domain signal refers to the sum of the energies of each frequency point in the second environment time domain signal;

[0033] Calculating the total energy of the first ear canal time domain signal, wherein the first ear canal time domain signal includes multiple frequency points, and the total energy of the first ear canal time domain signal refers to the sum of the energies of each frequency point in the first ear canal time domain signal;

[0034] If the difference between the total energy of the second environment time domain signal and the total energy of the first ear canal time domain signal is less than a preset third energy threshold, time-frequency conversion processing is performed on the first ear canal time domain signal.

[0035] Optionally, after adjusting the gain value of the preset noise reduction filter to the target gain value, the method further includes:

[0036] Based on the adjusted noise reduction filter, the first environmental time domain signal and the second ear canal time domain signal are respectively subjected to noise reduction filtering to obtain an active noise reduction signal; wherein the second ear canal time domain signal refers to the sound wave signal in the ear canal collected within the preset time after the first ear canal time domain signal is collected.

[0037] According to a second aspect of the present disclosure, a noise reduction device is provided, the noise reduction device comprising:

[0038] A first acquisition module is configured to acquire a first ear canal time domain signal, wherein the first ear canal time domain signal refers to a sound wave signal in the ear canal represented by a time domain representation;

[0039] A first processing module is configured to perform time-frequency conversion processing on the first ear canal time domain signal to obtain an ear canal frequency domain signal corresponding to the first ear canal time domain signal, wherein the ear canal frequency domain signal refers to a sound wave signal in the ear canal represented by a frequency domain representation;

[0040] The first processing module is further configured to obtain the total energy of the residual noise according to the preset weighting factor and the ear canal frequency domain signal, wherein the residual noise refers to the predicted sound wave signal heard by the human ear;

[0041] The first processing module is further configured to select, based on a pre-stored filter gain value list, one of a plurality of filter gain values ​​in the filter gain value list as a target gain value if the total energy of the residual noise is greater than or equal to a preset first energy threshold, wherein the target gain value can make the total energy of the residual noise less than the first energy threshold;

[0042] A first adjustment module is configured to adjust a gain value of a preset noise reduction filter to the target gain value;

[0043] The first adjustment module is further configured to perform noise reduction filtering on the first environmental time domain signal based on the adjusted noise reduction filter to obtain an active noise reduction signal, wherein the first environmental time domain signal refers to a sound wave signal in the environment around the headset expressed in a time domain manner, and the active signal is used to cancel noise;

[0044] The first adjustment module is further configured to send the active noise reduction signal to a speaker so that the speaker plays the active noise reduction signal.

[0045] According to a third aspect of the present disclosure, a noise-cancelling headset is provided, comprising a housing and a feedforward microphone, a feedback microphone, a speaker, and a controller arranged on the housing:

[0046] The feedforward microphone is used to collect sound wave signals in the environment surrounding the earphone;

[0047] The feedback microphone is used to collect sound wave signals in the ear canal;

[0048] The speaker is used to play sound wave signals;

[0049] The controller is communicatively connected to the feedforward microphone, feedback microphone and speaker respectively, and includes a processor and a memory, wherein the memory stores computer program instructions executable by the processor, and the processor is configured to call the computer program instructions to execute the noise reduction method as described in the first aspect.

[0050] According to a fourth aspect of the present disclosure, a non-temporary computer-readable storage medium is provided, on which computer program instructions are stored. When the computer program instructions are called by a processor, the noise reduction method as described in the first aspect is executed.

[0051] The technical solution provided by the embodiments of the present disclosure may include the following beneficial effects: in the present disclosure, by obtaining the total energy of the residual noise and selecting the target gain value in the pre-stored filter gain value list, the active noise reduction effect is compensated to solve the problem of decreased active noise reduction effect caused by sound leakage, thereby improving the noise reduction effect of the audio playback device and improving the user's auditory experience.

[0052] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0054] Figure 1 The figure is a schematic diagram showing the principle of a noise reduction headset according to an exemplary embodiment.

[0055] Figure 2 is a flow chart of a noise reduction method according to an exemplary embodiment.

[0056] Figure 3is a flow chart of a noise reduction method according to an exemplary embodiment.

[0057] Figure 4 is a flow chart of a noise reduction method according to an exemplary embodiment.

[0058] Figure 5 is a flow chart of a noise reduction method according to an exemplary embodiment.

[0059] Figure 6 is a flow chart of a noise reduction method according to an exemplary embodiment.

[0060] Figure 7 is a schematic diagram of a noise reduction device according to an exemplary embodiment.

[0061] Figure 8 The figure is a schematic diagram of the structure of a noise reduction headset according to an exemplary embodiment. DETAILED DESCRIPTION

[0062] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention as detailed in the appended claims.

[0063] Active Noise Cancellation (ANC) technology is a technology that generates a sound signal with the same energy as the noise but opposite phase to the noise, causing the sound signal to interfere with the noise source and achieve sound wave cancellation. Active noise cancellation technology is widely used in multimedia fields with audio playback functions such as headphones, car speaker systems, and smart homes.

[0064] Currently, after users wear headphones for a long time, a gap is created between the headphones and the ear canal, and the fit between the headphones and the ears decreases, resulting in poor active noise reduction effect.

[0065] Active noise reduction headphones can provide users with a comfortable environment and are gradually becoming more popular with users. The "active noise reduction" of headphones is a concept corresponding to "passive noise reduction". Passive noise reduction is that headphones reduce the ambient noise transmitted to the ear canal through physical isolation, while active noise reduction is achieved on the basis of passive noise reduction. The implementation method of active noise reduction has been explained above and will not be repeated here.

[0066] like Figure 1As shown, a noise reduction headset with active noise reduction function is exemplarily shown, and the acoustic components of the headset include a feedforward microphone 1, a feedback microphone 2 and a speaker 3. The speaker 3 is an audio output device of the headset and can emit sound for the user to listen to. The feedforward microphone 1 is arranged outside the headset and away from the speaker 3. The feedforward microphone 1 is used to monitor external environmental noise. The feedback microphone 2 is arranged inside the headset and close to the speaker 3, so that when the headset is worn, the feedback microphone 2 is closer to the auricle. The feedback microphone 2 is used to collect sound signals near the auricle to monitor the noise near the auricle.

[0067] Among them, the feedforward microphone 1 and the speaker 3 form a feedforward active noise reduction path 4, and the feedback microphone 2 and the speaker 3 form a feedback active noise reduction path 5. The feedforward active noise reduction path 4 includes a feedforward active noise reduction filter and circuit implemented by a chip, and the feedback active noise reduction path 5 includes a feedback active noise reduction filter and circuit implemented by a chip. Among them, due to the cost constraints of the chip, active noise reduction headphones usually use a fixed filter configuration, that is, the filter chip cannot modify the parameters in real time to adapt to different wearing environments, and can only adjust the active noise signal used to offset external noise by adjusting the gain of the filter.

[0068] Among them, when wearing headphones for a long time, the fit between the headphones and the ears decreases, and a gap is created between the headphones and the ear canal, resulting in a reduction in the active noise reduction effect and obvious sound leakage, such as high-frequency pain points. In addition, during the actual wearing process, it is difficult for users to repeatedly correct the wearing state, reducing the user experience.

[0069] In order to solve the above technical problems, the present disclosure provides a noise reduction method, which obtains a first ear canal time domain signal and performs time-frequency conversion processing to obtain an ear canal frequency domain signal corresponding to the first ear canal time domain signal. According to the preset weighting factor and the ear canal frequency domain signal, the total energy of the residual noise is obtained. If the total energy of the residual noise is greater than or equal to the first energy threshold, one of the multiple filter gain values ​​in the filter gain value list is selected as the target gain value. The target gain value can make the total energy of the residual noise less than the first energy threshold. Based on the adjusted noise reduction filter, the first environmental time domain signal is subjected to noise reduction filtering to obtain an active noise reduction signal and send the active noise reduction signal to a speaker so that the speaker plays the active noise reduction signal. In the present disclosure, by obtaining the total energy of the residual noise and selecting the target gain within the preset gain range, the active noise reduction effect is compensated to solve the problem of decreased active noise reduction effect caused by sound leakage, improve the noise reduction effect of the audio playback device, and enhance the user's auditory experience.

[0070] An exemplary embodiment of the present disclosure provides a noise reduction method, which is applied to headphones with active noise reduction function, and the noise reduction method is executed by a controller in the headphones, the controller includes at least an electrical signal acquisition module, and the headphones include in-ear headphones, semi-in-ear headphones, headphones, etc. The controller also includes a playback module, and the playback module includes a playback control circuit and playback control software running on the playback control circuit.

[0071] Among them, Figure 2 As shown, the noise reduction method provided in this embodiment includes:

[0072] S100: Acquire a first ear canal time domain signal, wherein the first ear canal time domain signal refers to a sound wave signal in the ear canal represented by a time domain representation.

[0073] In this step, when collecting the sound signal, at least the sound signal collected by the feedback microphone, that is, the first ear canal time domain signal, is obtained. The feedback microphone is set in the ear canal, and the first ear canal time domain signal refers to the sound wave signal in the ear canal represented by the time domain expression. During the implementation of the method in this embodiment, the controller can also simultaneously obtain the sound signal collected by the feedforward microphone and the sound signal of the speaker in addition to the sound signal collected by the feedback microphone, so as to use them in subsequent steps. If the sound signal collected by the feedforward microphone or the sound signal of the speaker is not needed, the controller may not obtain these signals, and re-acquire them when needed later.

[0074] Among them, since the feedback microphone is set in the ear canal, therefore, by obtaining the first ear canal time domain signal of the feedback microphone and analyzing it in subsequent steps, the residual noise information in the ear canal can be accurately monitored, and the active noise reduction gain can be compensated. Among them, the duration of the feedback microphone collecting signals is 200 milliseconds to 1000 milliseconds, and the interval duration of obtaining the feedback timing information in this method can be equal to the duration of the feedback microphone collecting signals. During implementation, the signal sampling rate of the feedback microphone is greater than or equal to 16000Hz, and the specific signal sampling rate and signal sampling duration can be adjusted according to the different devices and scenarios in which the method in this embodiment is applied, and this embodiment does not make specific limitations.

[0075] S200. Perform time-frequency conversion processing on the first ear canal time domain signal to obtain an ear canal frequency domain signal corresponding to the first ear canal time domain signal, wherein the ear canal frequency domain signal refers to a sound wave signal in the ear canal represented by a frequency domain expression.

[0076] In the time domain coordinate system, the horizontal axis (X axis) is time, and the vertical axis is the change (amplitude) of the sound signal. The time domain information is mainly used to characterize the change of the sound signal over time. In general, in order to obtain the energy information of the sound signal and analyze the sound signal as a whole, it is necessary to obtain the expression of the sound signal in the frequency domain.

[0077] In this step, the first ear canal time domain signal is converted into a corresponding ear canal frequency domain signal, that is, the sound signal collected by the feedback microphone is converted from time domain expression to frequency domain expression. The ear canal frequency domain signal describes the frequency characteristics of the sound. In the feedback frequency domain coordinate system, the horizontal axis is the frequency point and the vertical axis is the energy value. Obtaining the ear canal frequency domain signal is conducive to analyzing the sound signal in the frequency domain, and then analyzing the residual noise in the ear canal collected by the feedback microphone according to the energy value, and then determining the target gain value for offsetting the noise.

[0078] The first ear canal time domain signal can be converted into an ear canal frequency domain signal by Fourier transform. It is understandable that, in addition to Fourier transform, other methods capable of realizing time-frequency conversion in the field of signal processing can also be used to convert the first ear canal time domain signal into an ear canal frequency domain signal.

[0079] S300: Obtain the total energy of residual noise according to a preset weighting factor and an ear canal frequency domain signal, wherein the residual noise refers to a sound wave signal predicted to be heard by a human ear.

[0080] Among them, the preset weighting factor is related to the energy value. For example, some noises with too low energy values ​​will not have a significant impact on users, so the weight of noises with too low energy values ​​can be reduced, or even 0 weight (that is, no processing is done after this part of the noise is detected). In addition, when processing some noises with too high energy values, due to the performance of the processing chip, the weight of noises with too high energy values ​​is also reduced, and can even be 0 weight. As for the energy values ​​of noises that often appear in life, such as the sound of advertisements and the sound of mechanical equipment, the weights of the energy values ​​of these noises that often appear in life are increased.

[0081] In this step, the ear canal frequency domain signal has multiple frequency points in the frequency domain. In the process of obtaining the total energy of the residual noise, the total energy of the residual noise in the ear canal is calculated based on the frequency points in the spectrum and the weight values ​​corresponding to the frequency points, using a preset calculation method, to provide a basis for subsequent adjustment of the gain value.

[0082] S400. If the total energy of the residual noise is greater than or equal to a first energy threshold, based on a pre-stored filter gain value list, select one of the multiple filter gain values ​​in the filter gain value list as a target gain value, wherein the target gain value can make the total energy of the residual noise less than the first energy threshold.

[0083] In this step, after obtaining the total energy of the residual noise, the total energy of the residual noise is compared with a preset first energy threshold, wherein the first energy threshold may be an empirical value stored in the controller of the headset or a predicted value of the sound model. If the total energy of the residual noise is greater than or equal to the first energy threshold, it indicates that the total energy of the residual noise is too large and has reached a level that affects the user's listening effect, and the gain value of the noise reduction filter needs to be adjusted. On the contrary, if the total energy of the residual noise is lower than the first energy threshold, it indicates that the total energy of the residual noise will not affect the user, and the gain value of the noise reduction filter may not be adjusted.

[0084] The filter gain value list is pre-stored in the device for executing the noise reduction method and has been written into the device before the device leaves the factory. In addition, when determining the target gain value for canceling noise based on the pre-stored filter gain value list, a direct selection method or a traversal method can be used. This embodiment does not make specific limitations, as long as a target gain value suitable for canceling the residual noise in the ear canal can be selected from the pre-stored filter gain value list.

[0085] In this embodiment, the active noise reduction effect is compensated by obtaining the total energy of the residual noise and selecting a target gain value from multiple filter gain values ​​to solve the problem of decreased active noise reduction effect caused by sound leakage, thereby improving the noise reduction effect of the headphones and enhancing the user's auditory experience.

[0086] S500: Adjust the gain value of the preset noise reduction filter to a target gain value.

[0087] In this step, it can be understood that when the noise reduction function of the noise reduction headphones is turned on, the noise reduction filter has a preset gain value, so that when the user turns on the noise reduction function, the ambient noise can be filtered to achieve active noise reduction. Among them, the gain value of the preset noise reduction filter can be set according to a certain gear, for example, mild noise reduction, deep noise reduction, etc. In actual applications, the user can adjust the gain value of the preset noise reduction filter, such as selecting the gain value of the preset noise reduction filter through an app in a smart device connected to the headphones.

[0088] However, when sound leakage is detected, the gain value of the preset noise reduction filter can no longer meet the active noise reduction requirements in the current state. At this time, it is necessary to adjust the gain value of the preset noise reduction filter to the target gain value obtained in the above steps to compensate for the residual noise caused by sound leakage and enhance the active noise reduction effect of the headphones.

[0089] S600. Based on the adjusted noise reduction filter, perform noise reduction filtering on the first environmental time domain signal to obtain an active noise reduction signal, wherein the first environmental time domain signal refers to a sound wave signal in the environment around the headphone expressed in a time domain manner, and the active noise reduction signal is used to cancel the noise.

[0090] In this step, the sound wave signal in the environment around the earphone is collected through a feedforward filter, and the sound wave signal is expressed in the time domain, which is recorded as the first environment time domain signal. The first environment time domain signal is subjected to noise reduction filtering by a noise reduction filter to obtain an active noise reduction signal, which is a sound wave signal with the same waveform and opposite phase as the external environment noise signal, and is used to offset the external environment noise.

[0091] S700: Send the active noise reduction signal to the speaker so that the speaker plays the active noise reduction signal.

[0092] In this step, the speaker serves as the output module of the headset. The determined active noise reduction signal is sent to the speaker, and the speaker plays the active noise reduction signal. The played active noise reduction signal enters the ear canal, and the external environmental noise and the active noise reduction signal are played at the same time. The two cancel each other out, and the residual noise generated by sound leakage is canceled out, thereby achieving noise reduction compensation and improving the noise reduction effect.

[0093] In this embodiment, by obtaining the total energy of the residual noise and selecting a target gain value from multiple filter gain values, the gain value of the preset noise reduction filter is adjusted to the target gain value, and the active noise reduction effect is compensated to solve the problem of decreased active noise reduction effect caused by sound leakage, thereby improving the noise reduction effect of the headphones and enhancing the user's auditory experience.

[0094] In an exemplary embodiment, Figure 3 As shown, this embodiment is a further explanation of the implementation of step S200 in the above embodiment. When performing time-frequency conversion processing on the first ear canal time domain signal, the method in this embodiment can be used, including the following steps:

[0095] S210. Perform windowing processing on the first ear canal time domain signal to obtain multiple frames of first ear canal sub-signals, wherein each window of the windowing processing includes n frequency points, and the first ear canal sub-signal refers to the sound wave signal in each window represented by a time domain expression.

[0096] When the first ear canal time domain signal is collected, multiple samplings are performed within the sampling duration to obtain multiple sampling points. The number of sampling points is generally large, thousands of sampling points or tens of thousands of sampling points. In this step, the expression of the first ear canal time domain signal is fb(n), where n represents the sampling point of the nth time domain. When the first ear canal time domain signal is windowed, the sampling signal between n sampling points among the many sampling points in the above sampling duration is used as a window with a window length of N, that is, it can be considered that the window length of each window is N, and a window contains n time domain sampling points. For example, the entire sound signal has a total of 1000 time domain sampling points, and the window length N is 200, then the entire signal collected can be divided into 5 windows with no overlapping parts. It can be understood that when there are overlapping parts between adjacent windows, the entire signal can be divided into more than 5 windows. Among them, one window is a frame, and this step can obtain multiple frames of time domain signals according to the number of windows added. After the first ear canal time domain signal fb(n) is processed by overlapping windowing with a window length of N, it is divided into M frame signals (i.e., it has M windows). The expression of a single window (i.e., a single frame signal) is x m (n), where m = 0, 1, 2, ..., M-1; n represents the nth time domain sampling point.

[0097] Here, it should be noted that if the number of time domain sampling points at the end of the entire sound signal during the frame windowing process is less than the window length of a window, these time domain sampling points will be discarded. For example, the window length is 10, the entire sound signal includes a total of 107 time domain sampling points, the starting sampling point of the last window is 100, but the window length is 10, and the remaining 7 sampling points are less than the window length of a window, so the last 7 sampling points will be discarded.

[0098] In this embodiment, when windowing the entire sound signal, overlapping windowing is used, that is, two adjacent windows are partially overlapped, usually with a 1 / 2 overlap. For example, the 0th sampling point to the 100th sampling point of the entire first ear canal time domain signal is used as the first window, and the 50th sampling point to the 150th sampling point is used as the second window.

[0099] When performing frame splitting and windowing processing, the expression of the window function is wn(n), where n represents the nth time domain sampling point. The window function can be, for example, a Hamming window, a Hanning window, or the like.

[0100] S220 . Perform time-frequency conversion on the first ear canal sub-signal of each frame based on the window function used in the windowing process to obtain an ear canal frequency domain signal.

[0101] The first ear canal time domain signal is framed and windowed to obtain multiple frames of the first ear canal sub-signal, and Fourier transform is performed to obtain a smooth ear canal frequency domain signal. The ear canal frequency domain signal FBm(k) is expressed as:

[0102]

[0103] In the above formula, e is a natural constant, π is the circumference of a circle, j is the imaginary part of a complex number, wn(n) is a window function, n represents the nth sampling point, m=0, 1, 2, ..., M-1, and N is the window length.

[0104] In this embodiment, the collected first ear canal time domain signal is framed, windowed, and time-to-frequency converted to obtain a smooth ear canal frequency domain signal, and an expression of the first ear canal time domain signal in the frequency domain is obtained, thereby preparing for the subsequent analysis and processing of the residual noise in the ear canal in the frequency domain.

[0105] In an exemplary embodiment, Figure 4 As shown, this embodiment further illustrates the implementation of step S300 in the above embodiment. The method in this embodiment includes:

[0106] S310. Obtain an average energy value of the kth frequency point in the spectrum of the first ear canal sub-signal in each frame, wherein the spectrum refers to a frequency spectrum of the sound wave signal expressed in the frequency domain after time-frequency conversion, and the spectrum includes multiple frequency points.

[0107] S320. Determine the energy value of the kth frequency point according to the signal sampling rate of the first auditory canal time domain signal and the window length N during windowing processing, wherein the window length N refers to the number of signal frequency points contained in each window during windowing processing.

[0108] S330: Determine a target weighting factor according to a preset weighting factor and the energy value of the kth frequency point.

[0109] S340: taking the product of the target weighting factor and the average energy value of the kth frequency point as the weighted energy value of the kth frequency point.

[0110] S350 , summing up the weighted energy values ​​of each frequency point in the spectrum to obtain the total energy of the residual noise.

[0111] In the above steps, the order between S310 to S330 is not limited.

[0112] In steps S310 and S340, there are multiple frequency points in the spectrum. In this step, the kth frequency point is selected as the frequency point for analysis, and the ear canal frequency domain signal is analyzed at this frequency point, wherein k can represent any frequency point. After the above-mentioned frame division and windowing processing, multiple frames of first ear canal sub-signals are formed. For each frame of the first ear canal sub-signal, the average energy value of each frame of the first ear canal sub-signal at the kth frequency point in the spectrum is obtained. Although, in this embodiment, the kth frequency point is used as a representative for explanation, it is only for the convenience of description. In the implementation process, each frequency point is processed accordingly.

[0113] Get the weighted energy value P at the kth frequency point in the first ear canal sub-signal of each frame FB The expression of (k) is:

[0114]

[0115] In the above formula, M is the number of windows, that is, the number of frames;

[0116] FBm(k)—ear canal frequency domain signal;

[0117] W(k)—weighting factor.

[0118] In calculating the weighted energy value P FB (k), the power spectrum of the ear canal frequency domain signal is obtained in the logarithmic domain, and the unit of the obtained value is db, i.e. decibel, which is more in line with the evaluation standard for sound signals.

[0119] In step S320, before determining the preset weighting factor, it is necessary to first determine the energy value of the kth frequency point. The energy value F(k) of the kth frequency point can be expressed as:

[0120]

[0121] In the above formula, fs is the signal sampling rate, N is the window length, and k is the frequency point. Among them, for the speaker signal, the signal collected by the feedforward microphone, and the signal collected by the feedback microphone, the same signal sampling rate should be used first. If the speaker signal, the signal collected by the feedforward microphone, and the signal collected by the feedback microphone do not use the same signal sampling rate, it is necessary to convert or re-collect the above three signals using a unified signal sampling rate.

[0122] In step S330, the preset weighting factor is pre-written into the noise reduction headset that implements the method in this embodiment. When determining the preset weighting factor, it can be determined based on an empirical value; it can also be determined by performing multiple tests. The preset weighting factor is related to the energy value of the kth frequency point. After the energy value of the kth frequency point is determined in step S320, the weighting factor corresponding to the energy value of the kth frequency point is searched in the preset weighting factors as the target weighting factor.

[0123] The expression of the preset weighting factor W(k) can be:

[0124]

[0125] In the above formula, F(k) is the energy value of the frequency point, and k represents the frequency point.

[0126] For example, when the energy value F(k) of the kth frequency point is determined to be 40dB, the weighting factor corresponding to the frequency point is 0. Similarly, when the energy value F(k) of the kth frequency point is 150dB, the target weighting factor is 5, and weighted processing is required when calculating the average energy value for the frequency point.

[0127] Among them, since the human ear does not perceive sounds less than 50dB obviously, this kind of sound will not affect the audio-visual experience, so the weight of the sound below this energy value is set to 0, that is, the noise below this energy value is ignored. At the same time, since the sound wave signal with an energy value greater than 3000dB is affected by the chip processing performance, the weight value corresponding to the sound wave signal with an energy value greater than 3000dB is also 0, that is, the noise above this energy value is ignored. The sound between 50dB and 500dB is a common sound range in life, so the weight factor of the noise within this energy value range is increased to obtain better noise reduction compensation. It should be noted that in actual use, the weighting value can be changed according to actual needs.

[0128] In step S350, after the above steps, the weighted energy values ​​corresponding to each frequency point in the spectrum are summed to obtain the total energy of the residual noise:

[0129] S(fb)=sum(P FB (k))

[0130] Where, fb is the time domain signal of the first ear canal;

[0131] P FB (k)—weighted energy value.

[0132] In this embodiment, the weighted energy value of each frequency point in the spectrum is first calculated, and then the weighted energy values ​​of all frequency points are summed to obtain the total energy of the residual noise. When calculating the weighted energy value of each frequency point, the weight value of the noise of the frequency band that often appears in life is increased to improve the comprehensive evaluation accuracy of the total energy of the residual noise, thereby improving the active noise reduction effect.

[0133] In an exemplary embodiment, Figure 5 As shown, this embodiment further illustrates the implementation of step S400 in the above embodiment. The method in this embodiment includes:

[0134] S410 , a pre-stored filter gain value list includes a plurality of filter gain values ​​that are sequentially set from small to large, and a target gain value is selected from the plurality of filter gain values ​​in a traversal manner.

[0135] S420 , during the traversal process, if the selected target gain value makes the total energy of the residual noise less than a first energy threshold, then stop the traversal.

[0136] In step S410, the filter gain value list is pre-stored in the headset. The gain values ​​may be selected in ascending order, and the increment step value may be, for example, 0.5 dB. After selecting a gain of a certain numerical strength, the total energy of the residual noise can be less than the first energy threshold, and the currently selected gain value is output as the target gain value. In other embodiments, the gain strength may also be selected in descending order.

[0137] It should be noted that when performing active compensation, since the effect of compensating the feedback active noise reduction path alone is poor, in practical applications, the compensation scheme usually adopts a separate feedforward active compensation path, or a combination of the feedforward active compensation path and the feedback active compensation path.

[0138] S430. If, after traversing each filter gain value in the pre-stored filter gain value list, the total energy of the residual noise corresponding to each filter gain value is greater than or equal to the first energy threshold, then, from the total energies of multiple residual noises corresponding to the multiple filter gain values, select the filter gain value corresponding to the minimum value of the total energies of the residual noises as the target gain.

[0139] In this step, exemplarily, taking the preset gain range of 0dB to 7dB as an example, as the gain intensity increases, after the total energy of the residual noise selects the highest gain intensity of 7dB, the total energy of the residual noise is still greater than the first energy threshold, then the gain value of 7dB is output as the target gain value.

[0140] In an exemplary embodiment, the method in the embodiment of the present disclosure further includes:

[0141] S510: Acquire a loudspeaker reference signal, where the loudspeaker reference signal refers to a sound wave signal played by a loudspeaker.

[0142] S520: Calculate the total energy of the speaker reference signal, where the speaker reference signal includes multiple frequency points, and the total energy of the speaker reference signal refers to the sum of the energies of each frequency point in the speaker reference signal.

[0143] S530: If the total energy of the loudspeaker reference signal is less than or equal to a preset second energy threshold, perform time-frequency conversion processing on the first ear canal time domain signal.

[0144] In step S510, when collecting the sound signal, the sound signal emitted by the speaker, that is, the speaker reference signal, can be obtained. By obtaining and analyzing the speaker reference signal, the total energy of the speaker reference signal can be accurately obtained in subsequent steps.

[0145] In step S520, the total energy of the loudspeaker reference signal is the sum of the absolute values ​​of the collected energies of each frequency point of the loudspeaker reference signal. E(spk) represents the total energy of the loudspeaker reference signal.

[0146] In step S530, the greater the total energy of the speaker reference signal, the greater the signal strength output by the speaker, for example, the volume of the currently played media is loud, which can cover the impact of environmental noise. α represents the second energy threshold. Therefore, when E(spk)>α, it means that gain compensation is not needed now, and the compensation process ends; and when E(spk)<α, the first ear canal time domain signal can be processed, and whether compensation is needed can be confirmed through subsequent steps, so as to perform gain compensation in time when sound leakage occurs. Among them, the second energy threshold can be adjusted according to actual conditions.

[0147] In this embodiment, before processing the first ear canal time domain signal, the total energy of the speaker reference signal is obtained first, and the total energy of the speaker reference signal is compared with the second energy threshold to ensure that gain compensation is performed under the leakage compensation calculation conditions, thereby improving the accuracy of gain compensation.

[0148] In an exemplary embodiment, the noise reduction method provided by the embodiment of the present disclosure further includes the following steps:

[0149] S610: Acquire a second environment time domain signal, where the second environment time domain signal refers to a sound wave signal in the environment surrounding the earphone collected within a preset time before the first environment time domain signal is collected.

[0150] S620. Calculate the total energy of the second environment time domain signal, wherein the second environment time domain signal includes multiple frequency points, and the total energy of the second environment time domain signal refers to the sum of the energies of each frequency point in the second environment time domain signal.

[0151] S630. Calculate the total energy of the first ear canal time domain signal, where the first ear canal time domain signal includes multiple frequency points, and the total energy of the first ear canal time domain signal refers to the sum of the energies of each frequency point in the first ear canal time domain signal.

[0152] S640: If the difference between the total energy of the second environment time domain signal and the total energy of the first ear canal time domain signal is less than a preset third energy threshold, perform time-frequency conversion processing on the first ear canal time domain signal.

[0153] In step S610, when collecting sound signals, the sound wave signal collected by the feedforward microphone can be obtained. The feedforward microphone is set on the outside of the earphone. The second environment is the external environment. The sound wave signal of the second environment collected is expressed by time-frequency expression to obtain the second environment time domain signal. The sound wave signal in the external environment collected by the feedforward microphone is obtained and analyzed, so that the noise information of the external environment can be accurately detected. Among them, the duration of the signal collected by the feedforward microphone is 200 milliseconds to 1000 milliseconds, and the interval duration of obtaining the feedforward timing information in this method can be equal to the duration of the feedforward microphone. During the implementation process, the signal sampling rate of the feedforward microphone is greater than or equal to 16000Hz. The specific signal sampling rate and signal sampling duration can be adjusted according to the different devices and scenarios of the method in this embodiment, and this embodiment is not limited.

[0154] In step S620, the total energy of the second environment time domain signal is the sum of the absolute values ​​of the energy values ​​of each frequency point obtained after the collected second environment time domain signal is converted into a time-frequency signal. E(ff) represents the total energy of the second environment time domain signal.

[0155] Step S630 is implemented in the same manner as step S620, where E(fb) represents the total energy of the first auditory canal time domain signal.

[0156] In step S640, it should be noted that when the earphone is not interfered by external force, the values ​​of E(ff) and E(fb) remain stable, and the difference between E(fb) and E(ff) is always lower than the third energy threshold, and the third energy threshold is represented by β, that is, E(fb)-E(ff)<β. In this case, the time domain signal of the first ear canal can be processed, and it can be confirmed through subsequent steps whether compensation is needed, so as to perform gain compensation in time when sound leakage occurs.

[0157] When the headset is subjected to external force (such as finger touch), the change of E(fb) is greater than that of E(ff), resulting in E(fb)-E(ff)≥β. For example, the user is adjusting the wearing posture by touching the device with a finger. Therefore, when E(fb)-E(ff)≥β, gain compensation is not suitable and the compensation process ends.

[0158] In this embodiment, before processing the first ear canal time domain signal, the energy of the second environment time domain signal is first obtained, and the total energy of the first ear canal time domain signal and the total energy of the second environment time domain signal are calculated, and the difference between the total energy of the second environment time domain signal and the total energy of the first ear canal time domain signal is calculated, and the difference is compared with the third energy threshold to ensure that gain compensation is performed under the leakage compensation calculation conditions, thereby improving the accuracy of gain compensation.

[0159] In an exemplary embodiment, after adjusting the gain value of the preset noise reduction filter to the target gain value, the following steps are further included:

[0160] Based on the adjusted noise reduction filter, the first environment time domain signal and the second ear canal time domain signal are respectively subjected to noise reduction filtering to obtain an active noise reduction signal, wherein the second ear canal time domain signal refers to a sound wave signal in the ear canal collected within a preset time after the first ear canal time domain signal is collected.

[0161] In this step, it can be understood that the processor processing process requires a certain amount of time. Therefore, after collecting the first ear canal time domain signal, the sound wave signal in the ear canal is collected again, and the sound wave signal at this moment is expressed in the time domain as a second ear canal time domain signal, and the second ear canal time domain signal is subjected to noise reduction filtering by the noise reduction filter.

[0162] In an exemplary embodiment, Figure 6 As shown, a flow chart of a noise reduction method is shown, and the noise reduction method includes:

[0163] S701. Acquire a first ear canal time domain signal, a second environment time domain signal, and a speaker reference signal.

[0164] S702: Obtain total energy of the loudspeaker reference signal according to the loudspeaker reference signal.

[0165] S703: Determine whether the total energy of the loudspeaker reference signal is greater than a second energy threshold.

[0166] If the total energy of the loudspeaker reference signal is greater than the second energy threshold, it means that it is not suitable for compensation at present, and the process ends; if not, step S704 is executed.

[0167] S704: Calculate the total energy of the first auditory canal time domain signal according to the first auditory canal time domain signal.

[0168] S705: Calculate the total energy of the second environment time domain signal according to the second environment time domain signal.

[0169] It should be noted that steps S704 and S705 may also be performed before step S703.

[0170] S706: Determine whether the difference between the total energy of the second environment time domain signal and the total energy of the first ear canal time domain signal is less than a third energy threshold.

[0171] If the difference is less than the third energy threshold, it means that compensation is not suitable at present, and the process ends; if not, step S707 is executed.

[0172] S707: Perform time-frequency conversion processing on the first ear canal time domain signal to obtain an ear canal frequency domain signal corresponding to the first ear canal time domain signal.

[0173] S708: Obtain the total energy of the residual noise according to the preset weighting factor and the ear canal frequency domain signal.

[0174] S709: Determine whether the total energy of the residual noise is greater than or equal to a first energy threshold.

[0175] If the total energy of the residual noise is greater than or equal to the first energy threshold, step S710 is executed to perform noise reduction compensation; if not, it means that there is no wearing looseness, or the compensation has achieved the expected result and no further compensation is needed, then step S713 is executed, for example, the gain value output after the previous round of detection process is selected and output as the target gain value for this compensation.

[0176] S710: Select a filter gain value from a pre-stored filter gain value list.

[0177] By selecting a gain value of appropriate strength in the filter gain value list, so that the total energy of the residual noise after gain is less than the first energy threshold, acoustic leakage gain compensation is achieved. The gain value range of the pre-stored filter gain value list can be, for example, 0-7dB.

[0178] S711. Determine whether all gain values ​​have been traversed.

[0179] If all gain values ​​have been traversed but the optimal gain value has not been found, step S713 is executed to select the filter gain value corresponding to obtaining the minimum total energy of residual noise from among all filter gain values; if not, step S712 is executed.

[0180] S712: Increase the filter gain value.

[0181] The filter gain value is increased according to a preset step value, the preset step value is, for example, 0.5 dB. All filter gain values ​​are selected in the order of increasing gain values ​​to obtain the optimal filter gain value. It is understood that in other embodiments, all filter gain values ​​can also be traversed in a decreasing order, as long as all filter gain values ​​can be selected.

[0182] S713: Select a filter gain value that can obtain the total energy of the minimum residual noise as the target gain value.

[0183] S714: Adjust the gain value of the preset noise reduction filter to the target gain value.

[0184] S715 . Perform noise reduction filtering on the first environment time domain signal based on the adjusted noise reduction filter to obtain an active noise reduction signal.

[0185] S716: Send the active signal to the speaker so that the speaker plays the active noise reduction signal.

[0186] The process ends after the optimal gain is output. It is understandable that the user's wearing condition and the surrounding noise are changing in real time, so the filter gain value determined by a single gain compensation is not applicable to all situations. Therefore, after the compensation ends and the preset time has passed, the next round of gain compensation needs to be started, and the preset time is, for example, 30s to 120s.

[0187] The present disclosure also provides a noise reduction device, such as Figure 7 As shown, the noise reduction device includes:

[0188] The first acquisition module 100 is configured to acquire a first ear canal time domain signal, wherein the first ear canal time domain signal refers to a sound wave signal in the ear canal represented by a time domain representation;

[0189] The first processing module 200 is configured to perform time-frequency conversion processing on the first ear canal time domain signal to obtain an ear canal frequency domain signal corresponding to the first ear canal time domain signal; wherein the ear canal frequency domain signal refers to a sound wave signal in the ear canal represented by a frequency domain representation;

[0190] The first processing module 200 is further configured to obtain the total energy of the residual noise according to a preset weighting factor and the ear canal frequency domain signal; wherein the residual noise refers to the predicted sound wave signal heard by the human ear.

[0191] The first processing module 200 is also configured to select one from a plurality of filter gain values ​​in the filter gain value list as a target gain value based on a pre-stored filter gain value list if the total energy of the residual noise is greater than or equal to a preset first energy threshold, wherein the target gain value can make the total energy of the residual noise less than the first energy threshold.

[0192] The first adjustment module 300 is configured to adjust the gain value of the preset noise reduction filter to a target gain value.

[0193] The first adjustment module 300 is also configured to perform noise reduction filtering on the first environmental time domain signal based on the adjusted noise reduction filter to obtain an active noise reduction signal, wherein the first environmental time domain signal refers to a sound wave signal in the environment surrounding the headphone represented by a time domain expression, and the active signal is used to cancel noise.

[0194] The first adjustment module 300 is further configured to send the active noise reduction signal to the speaker so that the speaker plays the active noise reduction signal.

[0195] In an exemplary embodiment, the noise reduction device further comprises:

[0196] A second acquisition module is configured to acquire a speaker reference signal;

[0197] The second processing module is configured to calculate the total energy of the loudspeaker reference signal.

[0198] The second adjustment module is configured to process the first ear canal time domain signal if the total energy of the loudspeaker reference signal is less than or equal to a second energy threshold.

[0199] In an exemplary embodiment, the noise reduction device further comprises:

[0200] A third acquisition module is configured to acquire a second environment time domain signal;

[0201] A third processing module is configured to calculate the total energy of the second environment time domain signal;

[0202] The third processing module is further configured to calculate the total energy of the first auditory canal time domain signal;

[0203] The third adjustment module is configured to perform time-frequency conversion processing on the first ear canal time domain signal if the difference between the total energy of the second environment time domain signal and the total energy of the first environment time domain signal is less than a third energy threshold.

[0204] The present disclosure also provides a noise reduction headset, such as an over-ear headset, an in-ear headset, etc. Figure 1 As shown, the noise reduction earphones include a shell and a feedforward microphone 1, a feedback microphone 2, a speaker 3 and a controller (not shown) arranged on the shell. The controller is electrically connected to the feedforward microphone 1, the feedback microphone 2 and the speaker 3, respectively. The controller includes a processor and a memory. The memory stores computer program instructions that can be executed by the processor. The processor is configured to call the computer program instructions to execute the noise reduction method provided in the above embodiment.

[0205] The feedforward microphone 1 , the feedback microphone 2 and the loudspeaker 3 have been described in the aforementioned embodiment and will not be described again here.

[0206] refer to Figure 8 As shown, the noise canceling headphones 800 also include one or more of the following components: a processing component 802 , a memory 804 , a power component 806 , a multimedia component 808 , an audio component 810 , an input / output (I / O) interface 812 , a sensor component 814 , and a communication component 816 .

[0207] The processing component 802 generally controls the overall operation of the noise canceling headset 800, such as operations associated with display, data communication, and recording operations. The processing component 802 may include one or more processors 820 to execute instructions to complete all or part of the steps of the above method. In addition, the processing component 802 may include one or more modules to facilitate the interaction between the processing component 802 and other components. For example, the processing component 802 may include a multimedia module to facilitate the interaction between the multimedia component 808 and the processing component 802.

[0208] The memory 804 is configured to store various types of data to support the operation of the noise cancelling headphones 800. Examples of such data include instructions for any application or method operating on the noise cancelling headphones 800. The memory 804 can be implemented by any type of volatile or non-volatile storage terminal or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0209] The power supply assembly 806 provides power to the various components of the noise cancelling headphones 800. The power supply assembly 506 may include a power management system, a power plug, and other components associated with generating, managing, and distributing power to the noise cancelling headphones 800.

[0210] The multimedia component 808 includes a screen that provides an output interface between the noise canceling headset 800 and the user. The touch panel includes one or more touch sensors to sense touch, slide, and gestures on the touch panel. The touch sensor can not only sense the boundaries of the touch or slide action, but also detect the duration and pressure associated with the touch or slide operation.

[0211] The audio component 810 is configured to output and / or input audio signals. For example, the audio component 810 includes a microphone (MIC), and when the noise reduction headset 800 is in an operating mode, such as a call mode, a recording mode, and a speech recognition mode, the microphone is configured to receive an external audio signal. The received audio signal can be further stored in the memory 804 or sent via the communication component 816. In some embodiments, the audio component 810 also includes a speaker for outputting audio signals.

[0212] The I / O interface 812 provides an interface between the processing component 802 and a peripheral interface module, which may be a button, etc. These buttons may include, but are not limited to, a home button, a start button, and a lock button.

[0213] The sensor assembly 814 includes one or more sensors for providing various aspects of status assessment for the noise cancelling headphones 800. For example, the sensor assembly 814 can detect the on / off state of the noise cancelling headphones 800, the relative positioning of the components, such as the component being the display of the noise cancelling headphones 800, and the sensor assembly 814 can also detect changes in the position of the noise cancelling headphones 800 or the noise cancelling headphones 800, the orientation or acceleration / deceleration of the noise cancelling headphones 800, and the temperature changes of the installation location of the noise cancelling headphones 800. The sensor assembly 814 may include a proximity sensor configured to detect the presence of a nearby object without any physical contact. In some embodiments, the sensor assembly 814 may also include an accelerometer, a gyroscope sensor, a magnetic sensor, and a pressure sensor.

[0214] The communication component 816 is configured to facilitate wired or wireless communication between the noise cancelling headset 800 and other terminals. The noise cancelling headset 800 can access a wireless network based on a communication standard, such as WiFi, 2G, 3G, 4G, 5G, or a combination thereof. In an exemplary embodiment, the communication component 816 receives a broadcast signal or broadcast-related information from an external broadcast management system via a broadcast channel. In an exemplary embodiment, the communication component 816 also includes a near field communication (NFC) module to facilitate short-range communication. For example, the NFC module can be implemented based on radio frequency identification (RFID) technology, infrared data association (IrDA) technology, ultra-wideband (UWB) technology, Bluetooth (BT) technology, and other technologies.

[0215] In an exemplary embodiment, the noise canceling headphones 800 can be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing terminals (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors or other electronic components to perform the above-mentioned methods.

[0216] The embodiments of the present disclosure also provide a non-temporary computer-readable storage medium. When the instructions in the storage medium are executed by the processor of the noise-cancelling headphones, the noise-cancelling headphones can perform a noise reduction method, which includes any one of the noise reduction methods in the above embodiments.

[0217] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed in this disclosure. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0218] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A noise reduction method, characterized in that: Applied to headphones, the noise reduction method includes: Acquire a first ear canal time domain signal, wherein the first ear canal time domain signal refers to a sound wave signal in the ear canal represented by a time domain representation, and the first ear canal time domain signal is collected by a feedback microphone, and the feedback microphone is closer to the speaker than the feedforward microphone, and the feedforward microphone is used to monitor the external environment; Performing time-frequency conversion processing on the first ear canal time domain signal to obtain an ear canal frequency domain signal corresponding to the first ear canal time domain signal, wherein the ear canal frequency domain signal refers to a sound wave signal in the ear canal represented by a frequency domain representation; Obtaining the total energy of residual noise according to a preset weighting factor and the ear canal frequency domain signal, wherein the residual noise refers to a predicted sound wave signal heard by a human ear; If the total energy of the residual noise is greater than or equal to a preset first energy threshold, based on a pre-stored filter gain value list, selecting one of a plurality of filter gain values ​​in the filter gain value list as a target gain value, wherein the target gain value can make the total energy of the residual noise less than the first energy threshold; Adjusting the gain value of the preset noise reduction filter to the target gain value; Based on the adjusted noise reduction filter, performing noise reduction filtering on the first environmental time domain signal to obtain an active noise reduction signal, wherein the first environmental time domain signal refers to a sound wave signal in the environment around the earphone represented in a time domain representation manner, and the active noise reduction signal is used to cancel the noise; The active noise reduction signal is sent to a speaker so that the speaker plays the active noise reduction signal.

2. The noise reduction method according to claim 1, characterized in that: The performing time-frequency conversion processing on the first ear canal time domain signal to obtain an ear canal frequency domain signal corresponding to the first ear canal time domain signal includes: Performing windowing processing on the first ear canal time domain signal to obtain multiple frames of first ear canal sub-signals, wherein each window of the windowing processing includes n frequency points, and the first ear canal sub-signal refers to the sound wave signal in each window represented by a time domain representation; Based on the window function used in the windowing process, time-frequency conversion is performed on each frame of the first ear canal sub-signal to obtain the ear canal frequency domain signal.

3. The noise reduction method according to claim 2, characterized in that: The step of obtaining the total energy of the residual noise according to the preset weighting factor and the ear canal frequency domain signal comprises: Obtaining an average energy value of the kth frequency point in the spectrum of the first ear canal sub-signal of each frame, wherein the spectrum refers to the frequency spectrum of the sound wave signal expressed in the frequency domain after the time-frequency conversion, and the spectrum includes multiple frequency points; Determining the energy value of the kth frequency point according to the signal sampling rate of the first auditory canal time domain signal and the window length N when performing the windowing process, wherein the window length N refers to the number of signal frequency points contained in each window when performing the windowing process; Determining a target weighting factor according to the preset weighting factor and the energy value of the kth frequency point; The product of the target weighting factor and the average energy value of the k-th frequency point is used as the weighted energy value of the k-th frequency point; The weighted energy values ​​of each frequency point in the spectrum are summed to obtain the total energy of the residual noise.

4. The noise reduction method according to claim 3, characterized in that: The step of selecting one of the plurality of filter gain values ​​in the filter gain value list as a target gain value based on the pre-stored filter gain value list comprises: The pre-stored filter gain value list includes a plurality of filter gain values ​​set in order from small to large, and the target gain value is selected from the plurality of filter gain values ​​in a traversal manner; During the traversal process, if the selected target gain value makes the total energy of the residual noise less than the first energy threshold, then the traversal is stopped; If, after traversing each filter gain value in the pre-stored filter gain value list, the total energy of the residual noise corresponding to each filter gain value is greater than or equal to the first energy threshold, then, from the total energies of the multiple residual noises corresponding to the multiple filter gain values, the filter gain value corresponding to the minimum value of the total energies of the multiple residual noises is selected as the target gain value.

5. The noise reduction method according to claim 1, characterized in that: Before performing time-frequency conversion processing on the first auditory canal time domain signal, the noise reduction method further includes: Acquire a loudspeaker reference signal, wherein the loudspeaker reference signal refers to a sound wave signal played by a loudspeaker; Calculating the total energy of the speaker reference signal, wherein the speaker reference signal includes multiple frequency points, and the total energy of the speaker reference signal refers to the sum of the energies of each frequency point in the speaker reference signal; If the total energy of the loudspeaker reference signal is less than or equal to a preset second energy threshold, time-frequency conversion processing is performed on the first ear canal time domain signal.

6. The noise reduction method according to claim 1 or 5, characterized in that: Before performing time-frequency conversion processing on the first auditory canal time domain signal, the noise reduction method further includes: Acquire a second environment time domain signal, wherein the second environment time domain signal refers to a sound wave signal in the environment surrounding the earphone collected within a preset time before collecting the first environment time domain signal; Calculating the total energy of the second environment time domain signal, wherein the second environment time domain signal includes multiple frequency points, and the total energy of the second environment time domain signal refers to the sum of the energies of each frequency point in the second environment time domain signal; Calculating the total energy of the first ear canal time domain signal, wherein the first ear canal time domain signal includes multiple frequency points, and the total energy of the first ear canal time domain signal refers to the sum of the energies of each frequency point in the first ear canal time domain signal; If the difference between the total energy of the second environment time domain signal and the total energy of the first ear canal time domain signal is less than a preset third energy threshold, time-frequency conversion processing is performed on the first ear canal time domain signal.

7. The noise reduction method according to claim 6, characterized in that: After adjusting the gain value of the preset noise reduction filter to the target gain value, the noise reduction method further includes: Based on the adjusted noise reduction filter, the first environmental time domain signal and the second ear canal time domain signal are respectively subjected to noise reduction filtering to obtain an active noise reduction signal; wherein the second ear canal time domain signal refers to the sound wave signal in the ear canal collected within the preset time after the first ear canal time domain signal is collected.

8. A noise reduction device, characterized in that: The noise reduction device comprises: A first acquisition module is configured to acquire a first ear canal time domain signal, wherein the first ear canal time domain signal refers to a sound wave signal in the ear canal represented by a time domain representation, and the first ear canal time domain signal is collected by a feedback microphone, and the feedback microphone is closer to the speaker than the feedforward microphone, and the feedforward microphone is used to monitor the external environment; A first processing module is configured to perform time-frequency conversion processing on the first ear canal time domain signal to obtain an ear canal frequency domain signal corresponding to the first ear canal time domain signal, wherein the ear canal frequency domain signal refers to a sound wave signal in the ear canal represented by a frequency domain representation; The first processing module is further configured to obtain the total energy of the residual noise according to the preset weighting factor and the ear canal frequency domain signal, wherein the residual noise refers to the predicted sound wave signal heard by the human ear; The first processing module is further configured to select, based on a pre-stored filter gain value list, one of a plurality of filter gain values ​​in the filter gain value list as a target gain value if the total energy of the residual noise is greater than or equal to a preset first energy threshold, wherein the target gain value can make the total energy of the residual noise less than the first energy threshold; A first adjustment module is configured to adjust a gain value of a preset noise reduction filter to the target gain value; The first adjustment module is further configured to perform noise reduction filtering on the first environmental time domain signal based on the adjusted noise reduction filter to obtain an active noise reduction signal, wherein the first environmental time domain signal refers to a sound wave signal in the environment around the headset expressed in a time domain manner, and the active noise reduction signal is used to cancel noise; The first adjustment module is further configured to send the active noise reduction signal to a speaker so that the speaker plays the active noise reduction signal.

9. A noise-cancelling headset, characterized in that: The noise reduction headset comprises a housing and a feedforward microphone, a feedback microphone, a speaker and a controller arranged on the housing: The feedforward microphone is used to collect sound wave signals in the environment surrounding the earphone; The feedback microphone is used to collect sound wave signals in the ear canal; The speaker is used to play sound wave signals; The controller is communicatively connected to the feedforward microphone, feedback microphone and speaker respectively, and includes a processor and a memory, wherein the memory stores computer program instructions executable by the processor, and the processor is configured to call the computer program instructions to execute the method as described in any one of claims 1-7.

10. A non-transitory computer-readable storage medium having computer program instructions stored thereon, characterized in that: When the computer program instructions are called by a processor, the method according to any one of claims 1 to 7 is executed.

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