Transparency noise reduction control method and system for wireless earphone, and wireless earphone
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HENGXUAN TECH (BEIJING) CO LTD
- Filing Date
- 2022-12-28
- Publication Date
- 2026-07-24
Smart Images
Figure CN115866474B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of headphones, and more specifically, to a method, system, and wireless headphone for transparent noise reduction control. Background Technology
[0002] With social progress and improved living standards, headphones have become an indispensable part of daily life. Traditional wired headphones connect to a wireless host (such as smartphones, laptops, and tablets) via a wire, which restricts the wearer's movement, especially inconvenient during exercise. Furthermore, the tangling and pulling of the headphone wire, as well as the stethoscope effect, negatively impact the user experience. While ordinary Bluetooth headphones eliminate the wire between the headphones and the wireless host, a wire still exists between the left and right ears. True wireless stereo headphones have emerged to address this need.
[0003] Headphones with active noise cancellation enable users to enjoy a comfortable noise-canceling experience in various noisy environments such as airports, subways, airplanes, and restaurants, and are increasingly gaining widespread market and customer recognition. The principle behind this is that the headphones actively emit sound waves with opposite phase to cancel out the sound waves (feedforward) or add a feedback acoustic path to the sound path (feedback) to reduce the noise heard by the ears. Additionally, in scenarios where it is necessary to receive external voice signals or ambient noise, headphones need to have pass-through functionality, allowing the wearer to better receive external voice signals, ambient noise, or various alarm sounds.
[0004] However, there exists a situation where, when a user is using headphones to make a call, and the person on the other end is nearby (for example, when a user is wearing headphones during a video or audio conference and someone in the same room or next to them is speaking), if the user doesn't remove the headphones, they can receive the call through the headphones' speaker and also hear the same audio source through the physical space, with significant differences in latency between the two, severely impacting the user experience. Clearly, existing headphones cannot solve this problem. Summary of the Invention
[0005] This disclosure is provided to address the aforementioned problems existing in the prior art.
[0006] This disclosure provides a pass-through noise reduction control method for wireless headphones, which can intelligently switch the working module of the headphones based on the correlation parameters between the wireless audio signal and the external audio signal when the headphones can receive wireless audio signals through a wireless connection and play them through the headphone speakers, and also receive external audio signals from the same source through an external microphone, without requiring the user to remove the headphones, thus improving the user experience.
[0007] The first solution disclosed herein provides a pass-through noise reduction control method for a wireless earphone. The wireless earphone includes an external microphone, a speaker, a pass-through module, and an active noise reduction module. The pass-through noise reduction control method includes: acquiring an external audio signal collected by the external microphone; acquiring a wireless audio signal played by the speaker from another device; determining a correlation parameter between the external audio signal and the wireless audio signal; and, based on the correlation parameter, switching the wireless earphone to either enable the pass-through module or the active noise reduction module.
[0008] The second aspect of this disclosure provides a pass-through noise reduction control system for wireless headphones, the pass-through noise reduction control system comprising: a pass-through module configured to pass through the wireless headphones; an active noise reduction module configured to actively reduce noise in the wireless headphones; and a processor configured to execute the pass-through noise reduction control method according to any one of the first aspects and embodiments of this disclosure.
[0009] The third aspect of this disclosure provides a wireless headset that includes the pass-through noise reduction control system described in the second aspect of this disclosure.
[0010] The aforementioned wireless headphone pass-through noise reduction control method, system, and wireless headphone, when it can receive wireless audio signals via wireless connection and play them through the headphone speaker, and also receive external audio signals from the same source via the external microphone, intelligently switches the working module of the headphone based on the correlation parameters between the wireless audio signal and the external audio signal, without requiring the user to remove the headphone, thus improving the user experience. Attached Figure Description
[0011] In drawings that are not necessarily drawn to scale, the same reference numerals may describe similar parts in different views. The same reference numerals with or without letter suffixes may indicate different instances of similar parts. The drawings illustrate various embodiments generally by way of example rather than limitation, and are used, together with the description and claims, to explain the disclosed embodiments. Where appropriate, the same reference numerals are used in all drawings to refer to the same or similar parts. Such embodiments are illustrative and not intended to be exhaustive or exclusive embodiments of the apparatus or method.
[0012] Figure 1 A schematic diagram illustrating the working principle of an active noise cancellation module according to an embodiment of the present disclosure is shown.
[0013] Figure 2 A schematic diagram illustrating the working principle of a transparent transmission module according to an embodiment of the present disclosure is shown;
[0014] Figure 3A flowchart of a pass-through noise reduction control method for wireless headphones according to an embodiment of the present disclosure is shown; and
[0015] Figure 4 A block diagram illustrating the configuration of a pass-through noise reduction control system for a wireless headset according to an embodiment of the present disclosure is shown. Detailed Implementation
[0016] To enable those skilled in the art to better understand the technical solutions of this application, the application will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments of this application will be further described in detail below with reference to the accompanying drawings and specific examples, but these are not intended to limit the scope of this application.
[0017] The terms "first," "second," and similar words used in this application do not indicate any order, quantity, or importance, but are merely used for distinction. Words such as "including" or "comprising" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well. The order of steps indicated by arrows in the accompanying drawings is merely illustrative and does not imply that the steps must be performed in the order shown by the arrows. Unless otherwise specified, steps may be combined or their execution order may be changed, performing them in a different order than indicated by the arrows, as long as the logical relationship between the steps is not affected.
[0018] In this document, wireless headphones may include either in-ear headphones or semi-in-ear headphones. The wireless headphones may include at least an external ear microphone, a speaker, and a pass-through noise reduction control system 200 (which includes an active noise reduction module 210 and a pass-through module 220). The input to the feedforward active noise reduction filter of the active noise reduction module 210 comes from the audio signal collected by the feedforward microphone, and the output of the feedforward active noise reduction filter is finally output to the speaker; the input to the feedforward pass-through filter of the pass-through module 220 comes from the audio signal collected by the feedforward microphone, and the output of the feedforward pass-through filter is finally output to the speaker; the wireless headphones receive wireless audio signals from another wireless device via a wireless connection and play them through the speaker. The external ear microphone can collect external ear audio signals.
[0019] First, combine Figure 1 and Figure 2 The working principles of the active noise cancellation module 210 and the pass-through module 220 included in the wireless earphone provided in this embodiment are described respectively. The active noise cancellation module 210 is configured to perform active noise cancellation control on the wireless earphone, while the pass-through module 220 is configured to perform pass-through control on the wireless earphone.
[0020] Figure 1 A schematic diagram illustrating the working principle of an active noise cancellation module in a wireless earphone according to an embodiment of the present disclosure is shown. Figure 1As shown, in the active noise cancellation module 210, the headphones implement the active noise cancellation process through a feedforward path and a feedback path. In some embodiments, on the feedforward path, the feedforward microphone 101a collects ambient noise outside the headphones. The ambient noise collected by the feedforward microphone 101a includes not only the noise generated by the surrounding environment, but also the audio component that leaks into the surrounding environment when the headphone speaker 107 plays the audio signal. This audio component is considered part of the ambient noise. After the collected ambient noise is processed by the gain of the analog gain 102a and the analog-to-digital converter 103a, it is transmitted to the first low-pass and downsampling filter 104a. The first low-pass and downsampling filter 104a can reduce the filter sampling rate, thereby reducing power consumption and the filter order, and thus reducing the area of the noise cancellation chip and reducing the cost. Subsequently, the feedforward active noise cancellation filter 111 filters the ambient noise signal that has passed through the first low-pass and downsampling filter 104a to perform noise reduction processing on the ambient noise collected by the feedforward microphone 101a. The noise-reduced ambient signal is transmitted to adder 109, then processed by digital-to-analog converter 106, and finally played by speaker 107. The feedforward filtered ambient noise played by speaker 107 cancels out the ambient noise reaching the ear in the air to achieve noise reduction.
[0021] In some embodiments, on the feedback path, the feedback microphone 101b collects intra-ear noise near the ear canal inside the earphone. The intra-ear noise includes audio echo signals generated during audio signal playback and residual signals in the ear after air cancellation. The collected intra-ear noise is processed by the analog gain 102b and the analog-to-digital converter 103b, and then transmitted to the second low-pass and downsampling filter 104b. The second low-pass and downsampling filter 104b reduces the filter sampling rate, thereby reducing power consumption and the filter order, which in turn reduces the area of the noise reduction chip and lowers the cost. Subsequently, the intra-ear noise signal after passing through the second low-pass and downsampling filter 104b is transmitted to the adder 110. The audio signal 105 to be played is the audio signal to be transmitted to the speaker 107 for playback. On one hand, it is transmitted to the adder 109, where it undergoes digital-to-analog conversion processing by the digital-to-analog converter 106 before being played by the speaker 107. On the other hand, it is transmitted to the echo filter 113, which cancels the audio echo signal generated after the audio signal 105 is played by the speaker 107. The audio signal 105 filtered by the echo filter 113 is then sent to the adder 110. The adder 110 integrates the in-ear noise processed by the second low-pass and downsampling filter 104b with the audio signal processed by the echo filter 113, thus eliminating the influence of the audio echo signal on the feedback path. The adder 110 then transmits the integrated noise signal to the feedback active noise cancellation filter 112 for filtering to achieve feedback noise reduction. The noise signal after feedback filtering is transmitted to the adder 109 after being limited by the limiter 108. After being processed by the digital-to-analog converter 106, it is played by the speaker 107.
[0022] The above describes the working principle of active noise cancellation in headphones based on embodiments of this disclosure. By filtering the noise on the feedforward and feedback paths respectively, and then playing it through the speaker, the active noise cancellation function of the headphones can be realized, improving the noise cancellation effect and enhancing the user's listening experience. In some embodiments of this disclosure, in the active noise cancellation module 210, the headphones implement the active noise cancellation function through the feedforward path.
[0023] Figure 2 A schematic diagram illustrating the working principle of a transparent transmission module for a wireless earphone according to an embodiment of the present disclosure is shown. Figure 2As shown, in the pass-through module 220, the headphones implement the pass-through process through a feedforward path and a feedback path. In some embodiments, on the feedforward path, the headphone's feedforward microphone 101a collects ambient sound outside the headphones. The collected ambient sound is processed by the analog gain 102a and the analog-to-digital converter 103a, and then transmitted to the first low-pass and downsampling filter 104a. The first low-pass and downsampling filter 104a can reduce the filter sampling rate, thereby reducing power consumption and the filter order, and thus reducing the chip area to reduce cost. Subsequently, the ambient sound signal after passing through the first low-pass and downsampling filter 104a is filtered by the feedforward pass-through filter 114 to simulate the ambient sound collected by the feedforward microphone 101a. The ambient signal after pass-through processing is transmitted to the adder 109, and then after digital-to-analog converter 106, it is played by the speaker 107. The ambient sound played by the speaker 107 after pass-through filtering approximates the external ambient sound when the user is not wearing headphones.
[0024] In some embodiments, on the feedback path, the headphone's feedback microphone 101b collects intra-ear noise at a location inside the headphone near the ear canal. The intra-ear noise includes audio echo signals generated during audio signal playback and residual signals after air cancellation. The collected intra-ear noise is processed by the analog gain 102b and the analog-to-digital converter 103b, and then transmitted to the second low-pass and downsampling filter 104b. The second low-pass and downsampling filter 104b reduces the filter sampling rate, thereby reducing power consumption and the filter order, which in turn reduces the chip area and lowers cost. Subsequently, the intra-ear noise signal after passing through the second low-pass and downsampling filter 104b is transmitted to the adder 110. The audio signal 105 to be played is the audio signal to be transmitted to the speaker 107 for playback. On one hand, it is transmitted to the adder 109, where it undergoes digital-to-analog conversion processing by the digital-to-analog converter 106 before being played by the speaker 107. On the other hand, it is transmitted to the echo filter 113, which cancels the audio echo signal generated after the audio signal 105 is played by the speaker 107. The audio signal 105 filtered by the echo filter 113 is then sent to the adder 110. The adder 110 integrates the in-ear noise processed by the second low-pass and downsampling filter 104b with the audio signal processed by the echo filter 113, thus eliminating the influence of the audio echo signal on the feedback path. The adder 110 then transmits the integrated noise signal to the feedback pass-through filter 115 for filtering to achieve feedback noise reduction. The noise signal, after feedback filtering, may be transmitted to adder 109 after passing through limiter 108, and then played by speaker 107 after digital-to-analog conversion processing by digital-to-analog converter 106. In some embodiments, digital-to-analog converter 106 includes upsampling and filtering circuits to enable digital-to-analog conversion processing to operate at a higher frequency; for example, when adder 109 operates at 384kHz, digital-to-analog conversion processing of digital-to-analog converter 106 operates at 384*64=24.576MHz.
[0025] The above describes the working principle of the headphone pass-through based on the embodiments of this disclosure. By simulating the ambient sound on the feedforward path and filtering the noise on the feedback path, the headphone pass-through function can be realized, improving the headphone's sound quality. In some embodiments of this disclosure, in the pass-through module 220, the headphone achieves the pass-through process through the feedforward path.
[0026] In the wireless earphones disclosed herein, the active noise cancellation module 210 and the pass-through module 220 are configured to share multiple earphone components, such as a feedforward microphone 101a, a feedback microphone 101b, and an echo filter 113. Upon switching to the appropriate module, the components contained within that module are connected accordingly. Of course, in some embodiments, the active noise cancellation module 210 and the pass-through module 220 may have their own independent components to make the two modules independent of each other; this application does not impose any particular limitation here.
[0027] In some embodiments, the microphone can be a digital microphone, in which case... Figure 1 The analog gain and the first analog-to-digital converter are not needed. In addition, the feedforward active noise reduction filter, feedback active noise reduction filter, feedforward pass-through filter, and feedback pass-through filter can be adaptive or fixed filters. They can be IIR structures, FIR structures, or a hybrid filter structure of IIR and FIR.
[0028] Additionally, for simplicity, the adaptive part has been removed from the diagram in the echo filter of the active noise reduction module and / or pass-through module. Of course, it is also possible that the echo filter is obtained by an adaptive algorithm.
[0029] Figure 3 A flowchart of a pass-through noise reduction control method for a wireless headset according to an embodiment of the present disclosure is shown. This pass-through noise reduction control method 300 comprises a pass-through noise reduction control system 200 in the wireless headset (see [link to documentation]). Figure 4 This is executed to switch the headphones to enable the pass-through module 220 and the active noise cancellation module 210. In addition to the active noise cancellation module 210 and the pass-through module 220, the pass-through noise cancellation control system 200 also includes at least a processor 230, such as... Figure 4 As shown. The processor 230 is configured to execute Figure 3 The transparent transmission noise reduction control method is shown.
[0030] like Figure 3 As shown, the transparent noise reduction control method 300 includes:
[0031] S310, acquire the external ear audio signal collected by the external ear microphone;
[0032] S320, acquire the wireless audio signal from another device played by the speaker;
[0033] S330, determine the correlation parameters between the external audio signal and the wireless audio signal; and
[0034] S340, based on the correlation parameters, the wireless earphone is switched to enable the pass-through module or the active noise cancellation module.
[0035] Next, the specific process of the transparent transmission noise reduction control method 300 provided in this disclosure will be described in detail in conjunction with the above steps S310-S340.
[0036] In step S310, the external ear microphone can be provided as a component of a wireless headset to collect external ear audio signals and transmit the collected external ear audio signals to the processor 230. For example, the external ear audio signals may be the audio of any person speaking in the same physical space while the user is participating in a video or audio conference, or the audio of any person speaking next to the user, and may also include ambient sound in the physical space where the user is located.
[0037] In step S320, the processor 230 acquires a wireless audio signal from another wireless device and plays the wireless audio signal through a speaker. This wireless audio signal may originate from the same sound source (i.e., the same speaker) as the external audio signal collected by the external microphone, or it may originate from a different sound source (i.e., different speakers), the determination depending on the correlation parameter between the two (described below). It should be understood that the wireless device here can be a mobile phone, tablet computer, desktop computer, router, etc. Wireless communication between the wireless device and the headset can be achieved via Bluetooth, WiFi, etc. The wireless device can acquire the wireless audio signal from a remote server.
[0038] Note that there is no particular restriction on the order of steps S310 and S320 here; they can be performed simultaneously or in a certain order.
[0039] In step S330, the processor 230 determines the correlation parameter between the external audio signal and the wireless audio signal based on the external audio signal and the wireless audio signal obtained in steps S310 and S320, so as to determine whether the two come from the same sound source.
[0040] Optionally, in an embodiment, before step S330, the pass-through noise reduction control method 100 further includes:
[0041] In step S350, the processor 230 determines whether the wireless audio signal contains continuous human speech content. If so, it determines the correlation parameter between the external ear audio signal and the wireless audio signal.
[0042] "Human speech content" refers to speech content related to human speech, such as statements made in audio and video conferences. In other words, correlation detection is only performed if the processor 230 determines that the wireless audio signal from another device contains continuous human speech audio. If the wireless audio signal is music or other audio played by the user and does not belong to audio and video communication with outsiders, then correlation detection is not performed. In this way, on the one hand, the power consumption of the headphones in this scenario can be reduced, and on the other hand, incorrect or unnecessary switching due to misjudgment can be avoided.
[0043] Here, the processor 230 identifies the content in the wireless audio signal using known technologies (such as voice recognition technology), which will not be elaborated upon here.
[0044] Furthermore, "continuous human voice signal" refers to a period of time that contains human voice signal exceeding a preset threshold. That is, the processor 230 will only determine that the wireless audio signal contains human voice content if the period of time that contains human voice signal exceeds the preset threshold.
[0045] In one embodiment, the correlation parameter refers to the peak value of the cross-correlation between the external ear audio signal and the wireless audio signal, i.e., the maximum value among the absolute values of multiple cross-correlation values. Accordingly, correlation detection here refers to detecting the similarity between the time-domain waveforms of the external ear audio signal and the wireless audio signal, or the similarity between the distributions of the spectral components of the two audio signals.
[0046] Specifically, this correlation parameter can be calculated using formula (1):
[0047]
[0048] Where corr1 is the cross-correlation value, outer is the external audio signal collected by the external microphone, audio2 is the wireless audio signal from another device, N is the number of audio signal samples, and the correlation parameter can be the peak value of corr1, that is, the maximum value of the absolute value of corr1.
[0049] In other embodiments, this correlation parameter can be calculated using formulas (2) and (3):
[0050]
[0051]
[0052] In this embodiment, the cross-correlation result is normalized by the intensity of the external audio signal acquired by the external microphone, and ps1 is the first power (intensity) of the external audio signal used for intensity normalization.
[0053] In some other embodiments, this correlation parameter can be calculated using formulas (4) and (5):
[0054]
[0055]
[0056] In this embodiment, the cross-correlation result is normalized by the external audio signal strength collected by the external microphone and the wireless audio signal strength from another wireless device, where ps2 is the second power (intensity) of the wireless audio signal used for intensity normalization.
[0057] Preferably, in some embodiments, the correlation parameter is the maximum absolute value among multiple cross-correlation values between the external audio signal and the wireless audio signal, excluding cross-correlation values with a delay less than a specific threshold (sixth threshold). For corr1(l) (l = 0, 1, 2, ... N), when calculating the peak value of the correlation value, the number of time delay sampling points N1 corresponding to l being less than the specific threshold is removed, and only the peak values of these correlation values, i.e., the maximum absolute values, of corr1(l) (l = N1, N1+1, ... N), are calculated. The reason for this is as follows: a portion of the wireless audio signal played by the headphone speaker leaks through the headphones and is thus collected by the external microphone. However, due to the close distance between the speaker and the external microphone, the audio signal collected by the external microphone due to this leakage has a relatively small delay compared to the wireless audio signal, such as within 1 millisecond or a few milliseconds. Therefore, removing the correlation values with smaller delays from the correlation values can reduce or eliminate misjudgments due to the leakage of the wireless audio signal, i.e., misjudging wireless audio signals that are not actually from the voice of the person next to you as the voice of the person next to you.
[0058] Optionally, in some embodiments, the correlation parameter can also be obtained through a frequency domain method. Specifically, this may include the following steps:
[0059] First, the frequency domain coherence coefficients of the external audio signal and the wireless audio signal are calculated based on formula (6) in the frequency domain.
[0060]
[0061] Among them, C y1y2 (w) is the frequency domain coherence coefficient, Φ y1y2 (w) represents the cross-power spectral density of the external audio signal and the wireless audio signal, Φ y1y1 (w) represents the power spectral density of the external audio signal, Φ y2y2 (w) represents the power spectral density of the wireless audio signal, and w represents the digital angular frequency.
[0062] Secondly, based on the calculated frequency domain coherence coefficient, the correlation parameters between the external audio signal and the wireless audio signal are calculated using formula (7).
[0063]
[0064] Where Γ is the correlation parameter, C y1y2 (w) is the frequency domain coherence coefficient, ind1 is the lower limit of the detection frequency range, such as 300Hz, and ind2 is the upper limit of the detection frequency range, such as 3KHz.
[0065] In step S340, the processor 230 initiates a switch based on the correlation parameters determined in step S330, so that the wireless earphone switches to either the pass-through module 220 or the active noise cancellation module 210.
[0066] Specifically, the processor 230 compares the determined correlation parameters with a preset threshold and takes corresponding switching actions based on the comparison results.
[0067] In some embodiments, when the wireless earphone is in a state where the pass-through module 220 is off, when the correlation parameter is greater than or equal to a preset first threshold, the pass-through module 220 is turned on while the active noise cancellation module 210 remains off, and the wireless audio signal is cut off or attenuated. Specifically, when the active noise cancellation module 210 is on (e.g., when the feedforward active noise cancellation filter 111 is on), the active noise cancellation module 210 is turned off (i.e., the feedforward active noise cancellation filter 111 is off), and the pass-through module 220 is turned on (e.g., the feedforward pass-through filter 114 is on); if the active noise cancellation module 210 was not turned on before the switch, it should remain off after the switch. In this embodiment, the correlation parameter exceeding the preset first threshold indicates that it is highly likely that the wireless audio signal received by the user wirelessly from another device is caused by a speaker talking to someone nearby or in the same room. The user hears the speaker's voice and ambient sound both wirelessly and physically. Simultaneously, while switching on the pass-through module 220, the playback of the wireless audio signal is stopped or the volume of the wireless audio signal is reduced. In this way, in pass-through mode, only external sounds are heard, without interference or minimal interference from the played wireless audio signal.
[0068] Here, the pass-through module 220 is activated by activating the feedforward pass-through filter 114; that is, activating the feedforward pass-through filter 114 means activating the pass-through module 220. However, in some embodiments, the feedback channel (i.e., the feedback pass-through filter 115) can be activated at this time, while in other embodiments, the feedback channel (i.e., the feedback pass-through filter 115) can be deactivated. Similarly, the active noise cancellation module 210 is activated by activating the feedforward active noise cancellation filter 111; that is, activating the feedforward active noise cancellation filter 111 means activating the active noise cancellation module 210. However, in some embodiments, the feedback channel (i.e., the feedback active noise cancellation filter 112) can be activated at this time, while in other embodiments, the feedback channel (i.e., the feedback active noise cancellation filter 112) can be deactivated.
[0069] In another embodiment, when the wireless earphone is in the state where the pass-through module 220 is off, when the correlation parameter is greater than or equal to a preset second threshold and the intensity of the external audio signal is greater than or equal to a third threshold, the pass-through module 220 is turned on while the active noise cancellation module 210 remains off, and the wireless audio signal is cut off or weakened. Specifically, when the active noise cancellation module 210 is on (i.e., the feedforward active noise cancellation filter 111 is on), the active noise cancellation module 210 is turned off (i.e., the feedforward active noise cancellation filter 111 is off), and the pass-through module 220 is turned on (i.e., the feedforward pass-through filter 114 is on); if the active noise cancellation module 210 was not turned on before the switch, then the active noise cancellation module 210 should also remain off after the switch. In this embodiment, if the intensity of the audio signal collected by the external microphone is high, the audio signal heard by the user through the physical space (i.e., the external audio signal) is also strong, and this audio signal has greater interference, so it is very necessary to switch. This situation could occur when the speaker of the wireless audio signal is not only in the same physical space as the user, but also relatively close or speaking loudly. Simultaneously, by switching on the pass-through module 220, the playback of the wireless audio signal is stopped or its volume is reduced. In this pass-through mode, only external sounds are heard, without interference from the playing wireless audio signal.
[0070] In some embodiments, when the wireless earphone is in the state where the active noise cancellation module 210 is off, if the correlation parameter is greater than or equal to a fourth threshold and the intensity of the external audio signal is less than a fifth threshold, the active noise cancellation module 210 is turned on while the pass-through module 220 remains off. Specifically, when the pass-through module 220 is on (i.e., when the feedforward pass-through filter 114 is on), the pass-through module 220 is turned off (i.e., the feedforward pass-through filter 114 is off), and the active noise cancellation module 210 is turned on (i.e., the feedforward active noise cancellation filter 111 is on); if the pass-through module 220 was not turned on before the switch, it should remain off after the switch. In this embodiment, if the intensity of the external audio signal collected by the external microphone is low, the audio signal heard by the user through the physical space is weak, and the interference of this audio signal is small. This situation may occur when the speaker of the wireless audio signal is in the same physical space as the user, but the distance may be slightly far, such as 5m or 10m. At this time, turning on the active noise cancellation module 210 can further reduce the audio sounds such as external speech and ambient sounds heard by the user through the physical space, thereby improving the user's listening experience of wireless audio signals.
[0071] It should be understood that the first threshold, second threshold, and fourth threshold for the correlation parameter in the above embodiments may be the same. Of course, in some embodiments, the first threshold, second threshold, and fourth threshold may also be partially different or different from each other.
[0072] Similarly, the third and fifth thresholds for the intensity of the external audio signal in the above embodiments can be the same. Of course, in some embodiments, the third and fifth thresholds can also be different.
[0073] The transparent noise reduction control method provided in this disclosure can intelligently switch the working module of the headphones based on the correlation parameters between the wireless audio signal played by the headphone speaker 107 from another device and the external audio signal collected by the external microphone, without requiring the user to remove the headphones, thus improving the user experience.
[0074] Furthermore, after switching the operating mode of the wireless headphones based on the above steps S310-S340, the pass-through noise reduction control method 300 further includes:
[0075] S360, continuously determine the correlation parameter between the external audio signal and the wireless audio signal. When the correlation parameter is less than the preset seventh threshold, turn off the pass-through module 220 and restore the working mode before switching.
[0076] It should be understood that if the correlation parameter is less than the seventh threshold (which can be the same as or different from the first threshold mentioned above), it is likely that the person next to you has finished speaking, and then it is possible that someone far away is speaking instead of someone nearby. Therefore, the feedforward pass-through filter 114 should be turned off, the mode before the switch should be restored, and the wireless audio signal should be received through the headphone speaker 107.
[0077] In the embodiments of this disclosure, the external ear microphone and the feedforward microphone 101a can be the same microphone, and the audio signal collected by the feedforward microphone 101a is the external ear audio signal. The feedforward microphone 101a can also be a group of microphones composed of multiple microphones. The feedforward microphone 101a is generally located outside the ear and can be used to collect ambient sound outside the ear. The external ear microphone can be the same microphone as the feedforward microphone 101a, or it can include other external ear microphones, such as other call microphones in the earphone, which can also be used as an external ear microphone or part of an external ear microphone. Alternatively, in some embodiments, the external ear microphone can be a separate microphone that is different from the feedforward microphone 101a or the call microphone.
[0078] Furthermore, during the switching process of processor 230, the feedforward active noise cancellation filter 111 and the feedforward pass-through filter 114 operate simultaneously. Within the switching time T1, the outputs of the feedforward active noise cancellation filter 111 and the feedforward pass-through filter 114 are weighted and finally output to speaker 107. For example, within time T1, the weight of the output of feedforward active noise cancellation filter 111 decreases from 1 to 0, while the weight of the output of feedforward pass-through filter 114 increases from 0 to 1, thus completing the switching process and turning off feedforward active noise cancellation filter 111. Within time T1, the change in weights can be linear or follow other functional curves, but it must be monotonic. Alternatively, it can be configured in tabular form.
[0079] In some embodiments, various RISC (Reduced Instruction Set Computer) processor IPs purchased from companies such as ARM can be used as the processor 230 of the control system of this application to perform corresponding functions, and the processing of external audio signals and wireless audio signals can be implemented using an embedded system (e.g., but not limited to a SOC). Specifically, commercially available modules (IPs) have many modules, such as, but not limited to, memory (the memory can be RAM or external extended memory connected to the IP), various communication modules (e.g., Bluetooth modules), codecs, buffers, etc. Others, such as antennas, microphones, and speakers, can be externally connected to the chip. An interface can be used to connect an external microphone for acquiring audio signals. Users can build ASICs (Application-Specific Integrated Circuits) based on purchased IPs or self-developed modules to implement various communication modules, codecs, and various steps of the method of this application, in order to reduce power consumption and cost. Note that the "transparent noise reduction control system" in this application refers to a system that controls the target device it is located in. This can generally refer to, for example, a chip, such as an ASIC implemented based on a SOC, but is not limited to this. Any hardware circuit, software-processor configuration, and hardware-software hybrid firmware capable of control can be used to implement this control system. For example, the processing executed by processor 230 can be implemented as executable instructions executed by a RISC processor, or it can be formed as different hardware circuit modules, or it can be formed as hardware-software hybrid firmware, which will not be elaborated here.
[0080] Furthermore, although exemplary embodiments have been described herein, their scope includes any and all embodiments based on this application that have equivalent elements, modifications, omissions, combinations (e.g., schemes involving intersections of various embodiments), adaptations, or alterations. Elements in the claims will be interpreted broadly based on the language used in the claims and are not limited to the examples described in this specification or during the implementation of this application, which will be interpreted as non-exclusive. Therefore, this specification and examples are intended to be considered illustrative only, and the true scope and spirit are indicated by the full scope of the following claims and their equivalents.
[0081] The above description is intended to be illustrative and not restrictive. For example, the above examples (or one or more of them) can be used in combination with each other. Other embodiments may be used by those skilled in the art upon reading the above description. Furthermore, in the above detailed description, various features may be grouped together to simplify the application. This should not be construed as an intention that a feature of an unclaimed application is necessary for any claim. Rather, the subject matter of this application may be less than all the features of an embodiment of a particular application. Thus, the claims are incorporated herein by reference as examples or embodiments, wherein each claim is independently considered as a separate embodiment, and these embodiments are contemplated as being able to be combined with each other in various combinations or arrangements. The scope of the invention should be determined by reference to the appended claims and the full scope of their equivalents.
[0082] The above embodiments are merely exemplary embodiments of this application and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within the spirit and scope of this application, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the present invention.
Claims
1. A method for pass-through noise reduction control in wireless headphones, characterized in that, The wireless earphone includes an external microphone, a speaker, a pass-through module, and an active noise cancellation module. The pass-through noise cancellation control method includes: Acquire external audio signals collected by the external ear microphone; Acquire the wireless audio signal from another device played by the speaker; Determine the correlation parameters between the external audio signal and the wireless audio signal; Based on the correlation parameters, it is determined whether the external audio signal and the wireless audio signal originate from the same sound source; When the wireless earphone is in the state where the pass-through module is off, when the correlation parameter is greater than or equal to the first threshold, it is determined that the external audio signal and the wireless audio signal come from the same sound source. The pass-through module is turned on and the active noise cancellation module is kept off, while the output of the wireless audio signal to the speaker is cut off or reduced.
2. The pass-through noise reduction control method according to claim 1, characterized in that, The pass-through noise reduction control method further includes: Determine whether the wireless audio signal contains continuous human speech content; if so, determine the correlation parameter between the external ear audio signal and the wireless audio signal.
3. The pass-through noise reduction control method according to claim 2, characterized in that, The pass-through noise reduction control method further includes: When the wireless earphone is in the state where the pass-through module is off, when the correlation parameter is greater than or equal to the second threshold and the intensity of the external audio signal is greater than or equal to the third threshold, the pass-through module is turned on while the active noise cancellation module is kept off, and the wireless audio signal is cut off or weakened.
4. The pass-through noise reduction control method according to claim 2, characterized in that, The pass-through noise reduction control method further includes: When the wireless earphone is in the state where the active noise cancellation module is off, if the correlation parameter is greater than or equal to the fourth threshold and the intensity of the external audio signal is less than the fifth threshold, the active noise cancellation module is turned on while the pass-through module remains off.
5. The pass-through noise reduction control method according to any one of claims 2 to 4, characterized in that, The correlation parameter is the maximum value among the absolute values of multiple cross-correlation values between the external audio signal and the wireless audio signal.
6. The pass-through noise reduction control method according to claim 5, characterized in that, The correlation parameter is the maximum absolute value among multiple cross-correlation values between the external audio signal and the wireless audio signal, excluding cross-correlation values with a time delay less than the sixth threshold.
7. The pass-through noise reduction control method according to any one of claims 2 to 4, characterized in that, The correlation parameters are calculated using frequency domain methods.
8. The pass-through noise reduction control method according to claim 1 or 3, characterized in that, The pass-through noise reduction control method further includes: The correlation parameter between the external audio signal and the wireless audio signal is continuously determined. When the correlation parameter is less than the seventh threshold, the pass-through module is turned off and the working mode before the switch is restored.
9. A pass-through noise reduction control system for wireless headphones, characterized in that, The transparent transmission noise reduction control system includes: A pass-through module configured to pass through the wireless earphone; An active noise cancellation module configured to perform active noise cancellation on the wireless earphones; and A processor configured to perform the pass-through noise reduction control method according to any one of claims 1-8.
10. A wireless earphone, characterized in that, Including the transparent noise reduction control system according to claim 9.
11. The wireless earphone according to claim 10, characterized in that, The wireless headphones include either in-ear headphones or semi-in-ear headphones.