WO2024119393A1 - 开放式可穿戴声学设备及主动降噪方法 - Google Patents

开放式可穿戴声学设备及主动降噪方法 Download PDF

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WO2024119393A1
WO2024119393A1 PCT/CN2022/137185 CN2022137185W WO2024119393A1 WO 2024119393 A1 WO2024119393 A1 WO 2024119393A1 CN 2022137185 W CN2022137185 W CN 2022137185W WO 2024119393 A1 WO2024119393 A1 WO 2024119393A1
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noise reduction
sound
signal
noise
speaker
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PCT/CN2022/137185
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English (en)
French (fr)
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张承乾
郑金波
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深圳市韶音科技有限公司
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Priority to PCT/CN2022/137185 priority Critical patent/WO2024119393A1/zh
Publication of WO2024119393A1 publication Critical patent/WO2024119393A1/zh

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  • the present invention relates to the field of audio technology, and in particular to an open wearable acoustic device and an active noise reduction method.
  • wearable devices with acoustic output functions are used by more and more users.
  • a listening method in which an acoustic device does not form a closed space with the human body i.e., an open-ear listening method, for example, there is no need to insert the acoustic device into the ear canal or cover the ear, or the surface of the acoustic device is provided with sound-permeable holes, so that an open space is formed between the eardrum and the acoustic device
  • wearable acoustic devices are called open wearable devices.
  • the open wearable acoustic device When the above-mentioned open wearable acoustic device is worn on the user's head, it will not form a closed space between the user's eardrum. Therefore, compared with closed acoustic devices (such as in-ear headphones, etc.), the sound emitted by the noise source outside the ear will enter the ear more. This allows the user to hear more ambient noise when wearing an open acoustic device, reducing the user's auditory experience. Therefore, it is necessary to provide an active noise reduction design based on an open wearable acoustic device.
  • closed acoustic devices such as in-ear headphones, etc.
  • This specification provides an open wearable acoustic device and an active noise reduction method, which can improve the active noise reduction effect.
  • the present specification provides an open wearable acoustic device, comprising: a support, a speaker, a second sound sensor module and a noise reduction circuit; wherein the speaker is physically connected to the support, and an open space is formed between the speaker and the eardrum of the user when the acoustic device is worn on the head of the user; the second sound sensor module is physically connected to the support, and is configured to collect a second sound and generate a second sound signal, wherein a transfer function from the speaker to the second sound sensor module and a transfer function from the speaker to the eardrum satisfy a first preset relationship, and the first preset relationship is independent of the posture of the acoustic device; the noise reduction circuit is configured to: obtain the second sound signal from the second sound sensor module, adjust the noise reduction parameters of the noise reduction circuit based on the second sound signal and the first preset relationship, and perform active noise reduction based on the adjusted noise reduction parameters.
  • the acoustic device also includes a first sound sensor module, which is physically connected to the support member and is configured to collect a first sound and generate a first sound signal, wherein the first sound signal includes an ambient noise signal from ambient noise; and in order to perform active noise reduction based on the adjusted noise reduction parameters, the noise reduction circuit: obtains the first sound signal from the first sound sensor module, filters at least one of the first sound signal or the second sound signal to generate a noise cancellation signal, and sends the noise cancellation signal to the speaker so that the speaker converts the noise cancellation signal into noise cancellation frequency to reduce the volume of the ambient noise at the eardrum.
  • a first sound sensor module which is physically connected to the support member and is configured to collect a first sound and generate a first sound signal, wherein the first sound signal includes an ambient noise signal from ambient noise
  • the noise reduction circuit obtains the first sound signal from the first sound sensor module, filters at least one of the first sound signal or the second sound signal to generate a noise cancellation signal, and sends the noise cancellation signal to the speaker so that the speaker convert
  • the first sound sensor module is far away from the eardrum relative to the speaker, and the phase of the ambient noise reaching the first sound sensor module is ahead of the phase of the ambient noise reaching the sound output end of the speaker; and the second sound sensor module is close to the eardrum relative to the speaker, and the phase of the ambient noise reaching the second sound sensor module lags behind the phase of the ambient noise reaching the sound output end of the speaker.
  • the noise reduction circuit in order to adjust the noise reduction parameters of the noise reduction circuit, the noise reduction circuit: measures the transfer function from the speaker to the second sound sensor module to obtain a first transfer function; determines the ambient noise at the eardrum based on the first transfer function, the first preset relationship and the second sound signal; and adjusts the noise reduction parameters of the noise reduction circuit with the goal of minimizing the ambient noise at the eardrum.
  • the noise reduction circuit in order to measure the first transfer function, sends a test audio signal to the speaker so that the speaker emits a corresponding test audio, and the test audio is collected by the second sound sensor module; obtains a collected audio signal collected by the second sound sensor module; and determines the first transfer function based on the test audio signal and the collected audio signal.
  • a transfer function from the ambient noise to the second sound sensor module and a transfer function from the ambient noise to the eardrum satisfy a second preset relationship, and the second preset relationship is independent of the posture of the acoustic device; and in order to adjust the noise reduction parameters of the noise reduction circuit, the noise reduction circuit: adjusts the noise reduction parameters of the noise reduction circuit based on the second sound signal, the first preset relationship and the second preset relationship.
  • the noise reduction circuit in order to adjust the noise reduction parameters of the noise reduction circuit, the noise reduction circuit: measures the transfer function from the speaker to the second sound sensor module to obtain a first transfer function; determines the ambient noise at the eardrum based on the first transfer function, the first preset relationship, the second preset relationship and the second sound signal; and adjusts the noise reduction parameters of the noise reduction circuit with the goal of minimizing the ambient noise at the eardrum.
  • the noise reduction circuit in order to adjust the noise reduction parameters of the noise reduction circuit, the noise reduction circuit: obtains the target operating mode indicated by the user in multiple operating modes of the acoustic device, wherein in each operating mode the noise reduction circuit corresponds to default noise reduction parameters, and different operating modes correspond to different default noise reduction parameters; and adjusts the default noise reduction parameters corresponding to the target operating mode based on the second sound signal and the first preset relationship.
  • the noise reduction circuit includes at least one of a feedforward filter or a feedback filter, wherein the feedforward filter is connected to the first sound sensor module and the speaker and is configured to filter the first sound signal, and the feedback filter is connected to the second sound sensor module and the speaker and is configured to filter the second sound signal; and the noise reduction parameters include at least one of the filtering parameters of the feedforward filter or the filtering parameters of the feedback filter.
  • the filtering parameter includes at least one of a filtering gain, a filtering phase, or a quality factor.
  • the noise reduction circuit includes a feedforward filter, which is connected to the first sound sensor module and the speaker and is configured to filter the first sound signal, and the noise reduction parameters include a filter gain of the feedforward filter; and in order to adjust the noise reduction parameters, the noise reduction circuit: determines a first filter gain required for the feedforward filter with minimizing the second sound signal as the noise reduction target; determines, based on the first filter gain and the first preset relationship, a second filter gain required for the feedforward filter when minimizing the ambient noise at the eardrum as the noise reduction target; and adjusts the current filter gain of the feedforward filter to the second filter gain.
  • the first sound signal also includes a leakage signal from the speaker, wherein, in order to filter the first sound signal, the noise reduction circuit: generates a quasi-ambient noise signal by reducing the component of the leakage signal in the first sound signal, and filters the quasi-ambient noise signal based on the adjusted noise reduction parameters.
  • the noise reduction circuit includes: at least one storage medium and at least one processor, wherein the storage medium stores at least one instruction set for performing noise reduction; the processor is communicatively connected to the speaker, the second sound sensor module and the at least one storage medium, wherein when the acoustic device is running, the at least one processor reads the at least one instruction set and executes according to the instructions of the at least one instruction set: obtaining the second sound signal from the second sound sensor module, adjusting the noise reduction parameters of the noise reduction circuit based on the second sound signal and the first preset relationship, and performing active noise reduction based on the adjusted noise reduction parameters.
  • the acoustic device is one of headphones, silencers, hearing aids, and acoustic glasses.
  • the present specification also provides an active noise reduction method, which is applied to the open wearable acoustic device as described in the first aspect, and the method includes: obtaining the second sound signal from the second sound sensor module through the noise reduction circuit, adjusting the noise reduction parameters of the noise reduction circuit based on the second sound signal and the first preset relationship, and performing active noise reduction based on the adjusted noise reduction parameters.
  • the acoustic device also includes a first sound sensor module, which is physically connected to the support member and configured to collect a first sound and generate a first sound signal, wherein the first sound signal includes an ambient noise signal from the ambient noise; and performing active noise reduction based on the adjusted noise reduction parameters, including: acquiring the first sound signal from the first sound sensor module, filtering at least one of the first sound signal or the second sound signal to generate a noise cancellation signal, and sending the noise cancellation signal to the speaker so that the speaker converts the noise cancellation signal into a noise cancellation frequency to reduce the volume of the ambient noise at the eardrum.
  • a first sound sensor module which is physically connected to the support member and configured to collect a first sound and generate a first sound signal, wherein the first sound signal includes an ambient noise signal from the ambient noise
  • active noise reduction based on the adjusted noise reduction parameters including: acquiring the first sound signal from the first sound sensor module, filtering at least one of the first sound signal or the second sound signal to generate a noise cancellation signal, and sending the noise cancellation signal to the speaker
  • the phase of the ambient noise measured by the first sound sensor module is ahead of the phase of the ambient noise arriving at the sound output end of the speaker; and the phase of the ambient noise measured by the second sound sensor module lags behind the phase of the ambient noise arriving at the sound output end of the speaker.
  • the noise reduction parameters of the noise reduction circuit are adjusted based on the second sound signal and the first preset relationship, including: measuring the transfer function from the speaker to the second sound sensor module to obtain a first transfer function; determining the ambient noise at the eardrum based on the first transfer function, the first preset relationship and the second sound signal; and adjusting the noise reduction parameters of the noise reduction circuit with the goal of minimizing the ambient noise at the eardrum.
  • the transfer function from the speaker to the second sound sensor module is measured to obtain a first transfer function, including: sending a test audio signal to the speaker so that the speaker emits a corresponding test audio, and the test audio is collected by the second sound sensor module; acquiring a collected audio signal collected by the second sound sensor module; and determining the first transfer function based on the test audio signal and the collected audio signal.
  • the noise reduction parameters of the noise reduction circuit are adjusted based on the second sound signal, the first preset relationship, and the second preset relationship, including: measuring the transfer function from the speaker to the second sound sensor module to obtain a first transfer function; determining the ambient noise at the eardrum based on the first transfer function, the first preset relationship, the second preset relationship, and the second sound signal; and adjusting the noise reduction parameters of the noise reduction circuit with the goal of minimizing the ambient noise at the eardrum.
  • adjusting the noise reduction parameters of the noise reduction circuit based on the second sound signal and the first preset relationship includes: obtaining a target operating mode indicated by the user in multiple operating modes of the acoustic device, wherein in each operating mode the noise reduction circuit corresponds to default noise reduction parameters, and different operating modes correspond to different default noise reduction parameters; and adjusting the default noise reduction parameters corresponding to the target operating mode based on the second sound signal and the first preset relationship.
  • the noise reduction circuit includes at least one of a feedforward filter or a feedback filter; wherein the feedforward filter is connected to the first sound sensor module and the speaker and is configured to filter the first sound signal, and the feedback filter is connected to the second sound sensor module and the speaker and is configured to filter the second sound signal; and the noise reduction parameters include at least one of the filtering parameters of the feedforward filter or the filtering parameters of the feedback filter.
  • the filtering parameter includes at least one of a filtering gain, a filtering phase, or a quality factor.
  • the noise reduction circuit includes a feedforward filter, which is connected to the first sound sensor module and the speaker and is configured to filter the first sound signal, and the noise reduction parameters include a filter gain of the feedforward filter; and based on the second sound signal and the first preset relationship, the noise reduction parameters of the noise reduction circuit are adjusted, including: determining a first filter gain required for the feedforward filter with minimizing the second sound signal as the noise reduction target; determining a second filter gain required for the feedforward filter when minimizing the ambient noise at the eardrum as the noise reduction target based on the first filter gain and the first preset relationship; and adjusting the current filter gain of the feedforward filter to the second filter gain.
  • the first sound signal also includes a leakage signal from the speaker
  • filtering the first sound signal based on the adjusted noise reduction parameters includes: generating a quasi-ambient noise signal by reducing the component of the leakage signal in the first sound signal, and filtering the quasi-ambient noise signal based on the adjusted noise reduction parameters.
  • the open wearable acoustic device and active noise reduction method include a second sound sensor module, a speaker and a noise reduction circuit.
  • the transfer function from the speaker to the second sound sensor module and the transfer function from the speaker to the eardrum satisfy a first preset relationship, and the first preset relationship is independent of the position of the acoustic device.
  • the noise reduction circuit can obtain a second sound signal from the second sound sensor module, adjust the noise reduction parameters based on the second sound signal and the first preset relationship, and perform active noise reduction based on the adjusted noise reduction parameters. Since the noise reduction circuit adjusts the noise reduction parameters based on the second sound signal and the first preset relationship, the adjusted noise reduction parameters meet the accurate noise reduction target, thereby improving the noise reduction effect of active noise reduction.
  • FIG1A shows a schematic diagram of a wearing scenario of an acoustic device provided according to an embodiment of this specification
  • FIG1B shows a schematic diagram of an acoustic device in an in-ear wearing manner
  • FIG1C shows a schematic diagram of an acoustic device using an ear-hanging wearing method
  • FIG1D shows a schematic diagram of an acoustic device that is worn in an ear-clip manner
  • FIG2 shows a schematic diagram of the hardware structure of an acoustic device provided according to an embodiment of this specification
  • FIG3 is a schematic diagram showing leakage signals collected by sound sensors at different positions in an acoustic device
  • FIG4 shows a flow chart of an active noise reduction method provided according to an embodiment of this specification
  • FIG5 is a schematic diagram showing an active noise reduction principle of an acoustic device provided according to an embodiment of this specification
  • FIG6 is a schematic diagram showing a noise reduction effect of an active noise reduction method provided according to an embodiment of this specification.
  • FIG7 shows a flow chart of another active noise reduction method provided according to an embodiment of this specification.
  • FIG8A is a schematic diagram showing a frequency response curve of feedforward noise reduction of ambient noise at the eardrum using different feedforward filter gains when the first user wears the acoustic device;
  • FIG8B is a schematic diagram showing a frequency response curve of performing feedforward noise reduction on a second sound signal using different feedforward filter gains when the first user wears the acoustic device;
  • FIG9A is a schematic diagram showing a frequency response curve of feedforward noise reduction of ambient noise at the eardrum using different feedforward filter gains when a second user wears the acoustic device;
  • FIG9B is a schematic diagram showing a frequency response curve of performing feedforward noise reduction on a second sound signal using different feedforward filter gains when a second user wears an acoustic device;
  • FIG10 is a schematic diagram showing the distribution of the sound sensors when the first sound sensor module includes two sound sensors
  • FIG11 is a schematic diagram showing the distribution of the sound sensors when the first sound sensor module includes three sound sensors
  • FIG12 shows a flow chart of another active noise reduction method provided according to an embodiment of this specification.
  • FIG13 is a schematic diagram showing an active noise reduction principle of another acoustic device provided according to an embodiment of this specification.
  • FIG14 is a schematic diagram showing a set of frequency response curves provided according to an embodiment of this specification.
  • FIG. 15 is a schematic diagram showing another set of frequency response curves provided according to an embodiment of this specification.
  • FIG. 16 shows a flow chart of another active noise reduction method provided according to an embodiment of this specification.
  • Closed acoustic devices When some acoustic devices are worn, a closed space is formed between the acoustic device and the user's eardrum. Such acoustic devices can be called closed acoustic devices.
  • the acoustic device can adopt an in-ear design (such as earbud headphones), a closed earmuff design, or other similar designs to form a closed space between it and the user's eardrum.
  • the above-mentioned closed space can physically isolate external noise and reduce the interference of external noise on the user.
  • users usually feel uncomfortable when wearing closed acoustic devices for a long time.
  • Open acoustic devices When some acoustic devices are worn, an open space is formed between the acoustic device and the user's eardrum. Such acoustic devices can be called open acoustic devices. For example, the acoustic device may not be inserted into the ear canal or cover the ear canal, or the surface of the acoustic device may be provided with sound-transmitting holes to form an open space between it and the eardrum. Open acoustic devices can improve the wearing comfort of the user and make the sound heard by the user more transparent and natural.
  • Noise In this application, any sound that is unwelcome, unwanted, or disturbing to the user's hearing can be called noise.
  • Passive noise reduction may refer to the technology of noise reduction in a passive way.
  • the above passive methods include but are not limited to: eliminating (or partially eliminating) the noise source, preventing the spread of noise, or preventing the user's ears from hearing the noise, etc., or any combination thereof.
  • the technology of achieving noise reduction by forming a closed space in the ear belongs to passive noise reduction technology.
  • Passive noise reduction technology can also be called passive noise reduction technology. Passive noise reduction does not eliminate noise, but suppresses noise by physical means.
  • Active noise reduction may refer to a technology that actively reduces noise by generating a noise cancellation signal (for example, a signal with a phase opposite to the noise to be suppressed).
  • a noise cancellation signal for example, a signal with a phase opposite to the noise to be suppressed.
  • an acoustic device using active noise reduction technology can collect noise signals through a sound sensor, generate a noise cancellation signal for canceling the noise signal through a noise reduction circuit, and play the noise cancellation signal through a speaker so that the noise cancellation signal cancels the noise signal, thereby eliminating the noise.
  • Active noise reduction technology can also be called active noise reduction technology.
  • Active noise reduction technology can be divided into feedforward noise reduction, feedback noise reduction and hybrid noise reduction.
  • Feedforward noise reduction Place a sound sensor on the outside of the acoustic device, collect ambient noise through the sound sensor and generate an ambient noise signal, filter the ambient noise signal through a feedforward filter to generate a noise cancellation signal, and play the noise cancellation signal through a speaker.
  • the noise cancellation signal cancels (or partially cancels) the ambient noise at the eardrum, thereby reducing the volume of the ambient noise heard by the user.
  • the above-mentioned feedforward filter is mainly used to compensate for the difference between the ambient noise at the eardrum and the ambient noise collected by the sound sensor.
  • an open-loop noise reduction control system is formed between the speaker and the sound sensor.
  • a sound sensor is placed on the inside of the acoustic device, and the ambient noise in the area near the eardrum is collected through the sound sensor.
  • the ambient noise is filtered through a feedback filter to generate a noise reduction signal, and the noise reduction signal is played through the speaker.
  • the noise reduction signal cancels (or partially cancels) the ambient noise at the eardrum, thereby reducing the volume of the ambient noise heard by the user.
  • a closed-loop noise reduction control system is formed between the speaker and the sound sensor.
  • Hybrid noise reduction refers to the technology of combining feedforward noise reduction and feedback noise reduction. Generally speaking, compared with separate feedforward noise reduction or separate feedback noise reduction, hybrid noise reduction can further improve the noise reduction effect.
  • the present application provides an open wearable acoustic device (hereinafter referred to as "acoustic device”) and an active noise reduction method thereof, which can reduce the volume of ambient noise heard by the user and reduce the interference of ambient noise to the user in a scenario where the user wears the acoustic device.
  • acoustic device an open wearable acoustic device
  • active noise reduction method thereof which can reduce the volume of ambient noise heard by the user and reduce the interference of ambient noise to the user in a scenario where the user wears the acoustic device.
  • FIG1A shows a schematic diagram of a wearing scenario of an acoustic device provided according to an embodiment of the present specification.
  • the acoustic device 100 is worn on the user's ear 200.
  • the ear 200 may include an auricle 201 and an eardrum 202.
  • the acoustic device 100 may be worn on the auricle 201, and the acoustic device 100 and the eardrum 202 are not closed to form an open space.
  • a noise source 300 may also be included, and the number of noise sources 300 may be one or more.
  • the noise source 300 is configured to emit ambient noise (e.g., sound that is not welcomed by the user, is not wanted by the user, or interferes with the user's hearing).
  • the acoustic device 100 is configured to suppress or eliminate ambient noise heard by the human ear. Specifically, the acoustic device 100 adopts an active noise reduction method to suppress or eliminate ambient noise by generating and outputting a noise cancellation signal (a signal with a phase opposite to that of the ambient noise).
  • the acoustic device 100 can be headphones, silencers, hearing aids, acoustic glasses, etc., or any combination thereof.
  • FIG1A takes the acoustic device 100 as headphones as an example for illustration.
  • the acoustic device 100 is acoustic glasses, the area of the temples of the acoustic glasses close to the ears can be provided with a sound output device, which is configured to output sound to the user's ears.
  • the acoustic device 100 can be worn on the user's ears 200 in any manner, and this application does not limit this.
  • the wearing method of the acoustic device 100 can include head-mounted, in-ear wearing, around-the-neck wearing, ear-hanging wearing, or ear-clip wearing, etc., or any combination thereof.
  • scene 001 may also include: a network and a target device (not shown in FIG. 1A ).
  • the target device may be an electronic device with an audio output function.
  • the acoustic device 100 and the target device may be connected via network communication, and data or signals may be transmitted between the two via the network.
  • the target device may send the target audio (e.g., music, voice, etc.) to be played to the acoustic device 100 via the network, so that the acoustic device 100 may output the target audio to the user.
  • the target audio e.g., music, voice, etc.
  • the target device may be provided with an audio collection device, and the target audio is collected by the audio collection device.
  • the target device may receive the above-mentioned target audio from other devices.
  • the above-mentioned target device may include a mobile device, a tablet computer, a laptop computer, a built-in device of a motor vehicle, or the like, or any combination thereof.
  • the mobile device may include a smart home device, a smart mobile device, a virtual reality device, an augmented reality device, or the like, or any combination thereof.
  • the smart home device may include a smart TV, a desktop computer, a smart speaker, etc., or any combination thereof.
  • the smart mobile device may include a smart phone, a personal digital assistant, a gaming device, a navigation device, etc., or any combination thereof.
  • the virtual reality device or the augmented reality device may include a virtual reality helmet, virtual reality glasses, a virtual reality patch, an augmented reality helmet, augmented reality glasses, an augmented reality patch, or the like, or any combination thereof.
  • the virtual reality device or the augmented reality device may include Google Glass, a head-mounted display, VR, etc.
  • the built-in device in the motor vehicle may include an on-board computer, an on-board TV, etc.
  • the network can be any type of wireless network.
  • the network can include a telecommunications network, an intranet, the Internet, a local area network (LAN), a wide area network (WAN), a wireless local area network (WLAN), a metropolitan area network (MAN), a wide area network (WAN), a public switched telephone network (PSTN), a Bluetooth network, a ZigBee network, a near field communication (NFC) network, or a similar network.
  • the above network can be a Bluetooth network, in which case the acoustic device 100 and the target device can communicate based on the Bluetooth protocol.
  • the acoustic device 100 may include: a support 101 , a speaker 102 , a noise reduction circuit 105 , and at least one sound sensor module.
  • the speaker 102 and the at least one sound sensor module may be physically connected to the support 101 .
  • the support member 101 can be used to assist the acoustic device 100 in being fixed to the user's ear.
  • the support member 101 can be a shell or other additional structure of the acoustic device 100. It should be noted that the present application does not limit the specific shape of the support member 101. It should be understood that the specific shape of the support member 101 is related to the wearing method supported by the acoustic device 100.
  • FIG1B shows a schematic diagram of an acoustic device that is worn in the ear.
  • the support member 101 may be designed to fit the auricle 201, and one or more support points on the support member 101 fit the preset points on the auricle 201.
  • FIG1C shows a schematic diagram of an acoustic device that is worn by hanging ears. In this case, the support member 101 may adopt a suspension structure so that the acoustic device 100 can be suspended on the auricle 201.
  • FIG1D shows a schematic diagram of an acoustic device that is worn by clipping ears. In this case, the support member 101 may adopt a clamping structure so that the support member 101 can be clamped on the auricle 201.
  • the speaker 102 may be disposed on a side of the acoustic device 100 close to the ear canal opening.
  • an open space is formed between the speaker 102 and the user's eardrum 202.
  • the speaker 102 may be close to the user's ear canal opening without blocking the ear canal opening, thereby forming an open space between the speaker 102 and the eardrum 202.
  • the housing of the acoustic device 100 may adopt a non-enclosed housing, for example, a sound-transmitting hole is provided on the housing, so that an open space is formed between the speaker 102 and the eardrum 202.
  • the speaker 102 can be configured to generate audio based on an audio signal (or convert the audio signal into audio).
  • the audio signal here is an electrical signal that carries sound information, and audio refers to the sound signal played through the speaker.
  • the initial sound source such as an environmental noise source, a person's throat, etc.
  • the speaker 102 can also be called an electroacoustic transducer, which can receive the audio signal carrying the sound information when working, and then convert it into a sound signal to play it out.
  • the acoustic device 100 may include a plurality of speakers 102.
  • the plurality of speakers 102 can be arranged in an array, for example, a linear array, a planar array, a spherical array or other arrays.
  • the at least one sound sensor module may include a first sound sensor module 103. As shown in FIG1A , the first sound sensor module 103 is away from the eardrum 202 relative to the speaker 102. That is, the first sound sensor 103 may be arranged on the outside of the acoustic device 100 (when the acoustic device 100 is worn on the user's head, the side of the acoustic device 100 away from the eardrum 202 is the outside). In some embodiments, the first sound sensor module 103 may include one or more sound sensors.
  • the plurality of sound sensors may be arranged in an array, for example, a linear array, a planar array, a spherical array or other arrays.
  • the sound sensor is a device for collecting sound and converting sound into an electrical signal, such as a microphone.
  • the at least one sound sensor module may include a second sound sensor module 104.
  • the second sound sensor module 104 is close to (or near) the eardrum 202 relative to the speaker 102. That is, the second sound sensor module 104 is arranged on the inner side of the acoustic device 100 (when the acoustic device 100 is worn on the user's head, the side of the acoustic device 100 close to the eardrum 202 is the inner side).
  • the second sound sensor module 104 may include one or more sound sensors. When the second sound sensor module 104 includes a plurality of sound sensors, the plurality of sound sensors may be arranged in an array, for example, a linear array, a planar array, a spherical array or other arrays.
  • the at least one sound sensor module may include a first sound sensor module 103 and a second sound sensor module 104 at the same time.
  • the first sound sensor module 103 is configured to collect a first sound and generate a first sound signal corresponding to the first sound.
  • the first sound may be a sound analog signal, and the first sound signal may be an electrical signal.
  • the first sound sensor module 103 can collect the ambient noise emitted by the noise source 300.
  • the first sound sensor module 103 can also collect the sound emitted by the speaker 102.
  • the sound from the speaker 102 collected by the first sound sensor module 103 is referred to as leakage sound in this application. Therefore, the first sound collected by the first sound sensor module 103 includes ambient noise and leakage sound.
  • the first sound signal generated by the first sound sensor module 103 includes: an ambient noise signal from the noise source 300 and a leakage signal from the speaker 102.
  • the first sound sensor module 103 is far away from the eardrum 202 relative to the speaker 102, that is, the first sound sensor module 103 is closer to the noise source 300 relative to the speaker 102. Therefore, the time when the ambient noise reaches the first sound sensor module 103 is earlier than the time when the ambient noise reaches the sound output end of the speaker 102. In other words, the phase of the ambient noise reaching the first sound sensor module 103 is ahead of the phase of the ambient noise reaching the sound output end of the speaker 102. Therefore, the first sound signal collected by the first sound sensor module 103 can be used for feedforward noise reduction.
  • the second sound sensor module 104 is configured to collect a second sound and generate a second sound signal corresponding to the second sound.
  • the second sound may be a sound analog signal, and the second sound signal may be an electrical signal.
  • the second sound sensor module 104 can collect the ambient noise emitted by the noise source 300 on the one hand, and the sound emitted by the speaker 102 on the other hand. Therefore, the second sound collected by the second sound sensor module 104 includes the components of ambient noise and the components of the sound emitted by the speaker 102.
  • the ambient noise emitted by the noise source 300 is conducted along the air to reach the open space, and a part of the ambient noise in the open space is offset or weakened by the sound of the speaker 102 during the active noise reduction process. Therefore, the second sound collected by the second sound sensor module 104 can also be called residual noise, that is, the ambient noise remaining in the open space.
  • the second sound sensor module 104 is close to the eardrum 202 relative to the speaker 102, that is, the second sound sensor module 104 is farther from the noise source 300 relative to the speaker 102. Therefore, the time when the ambient noise reaches the second sound sensor module 104 is later than the time when the ambient noise reaches the sound output end of the speaker 102. In other words, the phase of the ambient noise reaching the second sound sensor module 104 lags behind the phase of the ambient noise reaching the sound output end of the speaker 102. Therefore, the second sound signal collected by the second sound sensor module 104 can be used for feedback noise reduction.
  • the noise reduction circuit 105 is connected to the first sound sensor module 103, the second sound sensor module 104 and the speaker 102, and is configured to perform active noise reduction to reduce the volume of the ambient noise heard by the human ear.
  • the above-mentioned active noise reduction can be any one of feedforward noise reduction, feedback noise reduction and hybrid noise reduction.
  • the noise reduction circuit 105 may be configured to perform feed-forward noise reduction. In this case, the noise reduction circuit 105 may obtain a first sound signal from the first sound sensor module 103 and perform active noise reduction based on the first sound signal.
  • the noise reduction circuit 105 performs active noise reduction based on the first sound signal, which may include: the noise reduction circuit 105 generates a first noise reduction signal based on the first sound signal.
  • the noise reduction circuit 105 sends the first noise reduction signal to the speaker 102, so that the speaker 102 converts the first noise reduction signal into a first noise reduction frequency.
  • the phase of the first noise reduction signal may be set to be opposite or approximately opposite to the phase of the ambient noise in the space at the eardrum 202, or to have a preset phase difference, so that the phase of the first noise reduction frequency is opposite or approximately opposite to the phase of the ambient noise at the eardrum 202 and the nearby space, thereby reducing the volume of the ambient noise at the eardrum 202.
  • the noise reduction circuit 105 may include a feedforward filter, which connects the first sound sensor module 103 and the speaker 102. After the noise reduction circuit 105 obtains the first sound signal from the first sound sensor 103, the first sound signal may be input into the feedforward filter, the first sound signal may be filtered by the feedforward filter to obtain the first noise reduction signal, and the first noise reduction signal may be output to the speaker 102.
  • the feedforward filter is configured to adjust at least one of the gain or the phase of the first sound signal, so that the obtained first noise reduction signal can offset at least part of the ambient noise at the eardrum 202 .
  • the noise reduction circuit 105 may also be configured to perform feedback noise reduction.
  • the noise reduction circuit 105 may obtain a second sound signal from the second sound sensor module 104 and perform active noise reduction based on the second sound signal.
  • the process of the noise reduction circuit 105 performing active noise reduction based on the second sound signal may include: the noise reduction circuit 105 generates a second noise reduction signal based on the second sound signal.
  • the noise reduction circuit 105 sends the second noise reduction signal to the speaker 102, so that the speaker 102 converts the second noise reduction signal into a second noise reduction frequency.
  • the second noise reduction signal may be set to be opposite, approximately opposite, or have a preset phase difference with the phase of the ambient noise at the eardrum 202, so that the phase of the second noise reduction frequency is opposite or approximately opposite to the phase of the ambient noise at the eardrum 202 and the surrounding space, thereby reducing the volume of the ambient noise at the eardrum 202.
  • the noise reduction circuit 105 may include a feedback filter, which connects the second sound sensor module 103 and the speaker 102. After the noise reduction circuit 105 obtains the second sound signal from the second sound sensor 103, the second sound signal may be input into the feedback filter, the second sound signal may be filtered by the feedback filter to obtain the second noise reduction signal, and the second noise reduction signal may be output to the speaker 102.
  • the feedback filter is configured to adjust at least one of the gain or the phase of the second sound signal, so that the obtained second noise reduction signal can offset at least part of the ambient noise at the eardrum 202 .
  • the noise reduction circuit 105 may also be configured to perform hybrid noise reduction.
  • the noise reduction circuit 105 may obtain a first sound signal from the first sound sensor module 103, obtain a second sound signal from the second sound sensor module 104, and perform active noise reduction based on the first sound signal and the second sound signal.
  • the process of the noise reduction circuit 105 performing active noise reduction based on the first sound signal and the second sound signal may include: the noise reduction circuit 105 generates a first noise reduction signal based on the first sound signal, and generates a second noise reduction signal based on the second sound signal.
  • the noise reduction circuit 105 sends the first noise reduction signal and the second noise reduction signal to the speaker 102, so that the speaker 102 converts the first noise reduction signal and the second noise reduction signal into noise reduction frequency to reduce the volume of the ambient noise at the eardrum 202 and the nearby space.
  • the noise reduction circuit 105 may include a feedforward filter and a feedback filter. Among them, the feedforward filter is connected to the first sound sensor module 103 and the speaker 102.
  • the feedback filter is connected to the second sound sensor module 104 and the speaker 102.
  • the noise reduction circuit 105 can input the first sound signal into the feedforward filter, filter the first sound signal through the feedforward filter to obtain the first noise reduction signal, and input the second sound signal into the feedback filter, filter the second sound signal through the feedback filter to obtain the second noise reduction signal. Then the noise reduction circuit 105 sends the first noise reduction signal and the second noise reduction signal to the speaker 102.
  • the feedforward filter is configured to adjust at least one of the gain or phase of the first sound signal, so that the audio generated by the obtained first noise reduction signal after conversion by the speaker 102 can offset at least part of the ambient noise at the eardrum 202 and the nearby space (that is, the phase of the audio is opposite or approximately opposite to the phase of at least part of the ambient noise at the eardrum 202 and the nearby space).
  • the feedback filter is configured to adjust at least one of the gain or phase of the second sound signal, so that the audio generated by the obtained first noise reduction signal after conversion by the speaker 102 can offset at least part of the ambient noise at the eardrum 202 (that is, the phase of the audio is opposite or approximately opposite to the phase of at least part of the ambient noise at the eardrum 202 and the nearby space).
  • the noise reduction circuit 105 can send the first noise reduction signal and the second noise reduction signal to the speaker 102 respectively. In some embodiments, the noise reduction circuit 105 can first synthesize the first noise reduction signal and the second noise reduction signal to obtain a synthesized noise reduction signal, and then send the synthesized noise reduction signal to the speaker 102.
  • the noise reduction circuit 105 may be configured to perform the active noise reduction method described in this specification. At this time, the noise reduction circuit 105 may store data or instructions for performing the active noise reduction method described in this specification, and may execute or be used to execute the data or instructions. In some embodiments, the noise reduction circuit 105 may include a hardware device with a data information processing function and a necessary program for driving the hardware device to work. The above-mentioned active noise reduction method will be described in detail in the following content.
  • FIG2 shows a schematic diagram of the hardware structure of an acoustic device provided according to an embodiment of the present specification.
  • the noise reduction circuit 105 may include: at least one storage medium 106 and at least one processor 107.
  • the at least one processor 107 is communicatively connected with the speaker 102, the first sound sensor module 103 and the second sound sensor module 104.
  • the noise reduction circuit 105 in the present application includes at least one storage medium 106 and at least one processor 107 for the purpose of demonstration only. It can be understood by one of ordinary skill in the art that the noise reduction circuit 105 may also include other hardware circuit structures, which are not limited in the present application, as long as they can meet the functions mentioned in the present application without deviating from the spirit of the present application.
  • the acoustic device 100 may further include a communication port 108.
  • the communication port 108 is used for data communication between the acoustic device 100 and the outside world, for example, the communication port 108 may be used for data communication between the acoustic device 100 and other devices.
  • the acoustic device 100 may further include an internal communication bus 109.
  • the internal communication bus 109 may connect different system components.
  • the speaker 102, the first sound sensor module 103, the second sound sensor module 104, the processor 107, the storage medium 106, and the communication port 108 may all be connected via the internal communication bus 109.
  • the storage medium 106 may include a data storage device.
  • the data storage device may be a non-temporary storage medium or a temporary storage medium.
  • the data storage device may include one or more of a disk 1061, a read-only storage medium (ROM) 1062, or a random access storage medium (RAM) 1063.
  • the storage medium 106 also includes at least one instruction set stored in the data storage device.
  • the instruction set includes instructions, which are computer program codes, and the computer program codes may include programs, routines, objects, components, data structures, processes, modules, etc. for executing the active noise reduction method provided in this specification.
  • At least one processor 107 is used to execute the at least one instruction set mentioned above.
  • at least one processor 107 reads the at least one instruction set and executes the active noise reduction method provided in this specification according to the instructions of the at least one instruction set.
  • the processor 107 can execute all or part of the steps included in the communication method.
  • the processor 107 can be in the form of one or more processors.
  • the processor 107 can include one or more hardware processors, such as a microcontroller, a microprocessor, a reduced instruction set computer (RISC), an application-specific integrated circuit (ASIC), an application-specific instruction set processor (ASIP), a central processing unit (CPU), a graphics processing unit (GPU), a physical processing unit (PPU), a microcontroller unit, a digital signal processor (DSP), a field programmable gate array (FPGA), an advanced RISC machine (ARM), a programmable logic device (PLD), any circuit or processor capable of performing one or more functions, etc., or any combination thereof.
  • a microcontroller such as a microcontroller, a microprocessor, a reduced instruction set computer (RISC), an application-specific integrated circuit (ASIC), an application-specific instruction set processor (ASIP), a central processing unit (CPU), a graphics processing unit (GPU), a physical processing unit (PPU), a microcontroller unit, a digital signal processor (DSP), a field programmable
  • the acoustic device 100 in this specification may also include multiple processors, and therefore, the operations and/or method steps disclosed in this specification may be performed by one processor as described in this specification, or may be performed jointly by multiple processors.
  • the processor 107 of the acoustic device 100 in this specification performs step A and step B
  • step A and step B may also be performed jointly or separately by two different processors 120 (for example, the first processor performs step A, the second processor performs step B, or the first and second processors perform steps A and B together).
  • FIG2 is only one design of the noise reduction circuit 105.
  • the noise reduction circuit 105 may also be designed in other hardware forms without departing from the spirit of the invention disclosed in this application.
  • the specific design of the noise reduction circuit 105 is not limited in this application.
  • the first sound signal collected and generated by the first sound sensor module 103 is not a pure ambient noise signal, but a mixed sound signal including an ambient noise signal and a leakage signal. Therefore, if the noise reduction circuit 105 performs feedforward noise reduction directly based on the first sound signal, the leakage signal will affect the feedforward noise reduction process, resulting in poor feedforward noise reduction effect.
  • the acoustic device 100 can use physical isolation to set the first sound sensor module 103 at the acoustic zero point of the speaker 102.
  • the speaker 102 can adopt the design of a dipole speaker, and the first sound sensor module 103 is located at the acoustic zero point of the dipole speaker. In this way, the first acoustic sensor module 103 cannot collect the leakage signal from the speaker 102, or only collects a small amount of leakage signal.
  • FIG3 is a schematic diagram showing leakage signals collected by sound sensors at different positions in an acoustic device.
  • FF1 and FF2 represent sound sensors located at the acoustic zero point of the speaker 102
  • FF3 represents a sound sensor located near the speaker 102.
  • the leakage signal collected by FF1 is obtained to obtain a curve 301 as shown in FIG3
  • the leakage signal collected by FF2 is obtained to obtain a curve 302 as shown in FIG3
  • the leakage signal collected by FF3 is obtained to obtain a curve 303 as shown in FIG3.
  • the distance between the first acoustic sensor module 103 and the acoustic zero point position of the speaker 102 may be within a non-zero preset range.
  • the first acoustic sensor module 103 may be disposed at a position close to the acoustic zero point position of the speaker 102, rather than being strictly located at the acoustic zero point position of the speaker 102. In this way, the requirements for the structural design and assembly process of the acoustic device 100 can be reduced.
  • the present application provides an active noise reduction method P100, which can reduce the influence of the leakage signal on the feedforward noise reduction by reducing the leakage signal component in the first sound signal, thereby improving the noise reduction effect.
  • the above-mentioned active noise reduction method P100 can be applied to the scenario of "the first sound sensor module 103 is not set at the acoustic zero point position of the speaker 102", and can also be applied to the scenario of "the first sound sensor module 103 is set at the acoustic zero point position of the speaker 102". In the scenario of "the first sound sensor module 103 is set at the acoustic zero point position of the speaker 102", since there is still a problem of the speaker signal leaking to the first sound sensor module in some frequency bands (for example, in FIG.
  • the active noise reduction method P100 provided in the present application can be used for active noise reduction for the above-mentioned specific frequency bands where leakage exists, so as to improve the noise reduction effect.
  • the active noise reduction method P100 can be independently applied to the acoustic device 100 provided in this application, or can be combined with other active noise reduction methods described in other parts of this document.
  • FIG4 shows a flow chart of an active noise reduction method provided according to an embodiment of the present specification.
  • the active noise reduction method P100 can be executed by the noise reduction circuit 105 in the acoustic device 100.
  • the processor 107 in the noise reduction circuit 105 can read the instruction set stored in its local storage medium, and then execute the active noise reduction method P100 described in the present specification according to the instruction set.
  • the active noise reduction method P100 may include:
  • S11 Acquire a first sound signal from a first sound sensor module, where the first sound signal includes an ambient noise signal from ambient noise and a leakage signal from a speaker.
  • the first sound sensor module 103 collects the first sound and converts the first sound into a first sound signal.
  • the first sound is actually a sound mixed with the ambient noise from the noise source 300 and the leakage sound from the speaker 102. Therefore, the first sound signal includes both the ambient noise signal corresponding to the ambient noise and the leakage signal corresponding to the leakage sound.
  • the noise reduction circuit 105 is connected to the first sound sensor module 103 and can obtain the first sound signal from the first sound sensor module 103.
  • S12 Generate a quasi-ambient noise signal by reducing the leakage signal component in the first sound signal.
  • the noise reduction circuit 105 can measure the components of the leakage signal contained in the first sound signal in some way, and then subtract the components of the leakage signal from the first sound signal to obtain a quasi-environmental noise signal. It should be noted that the components of the leakage signal obtained by the above measurement may deviate from the actual leakage signal. Therefore, the result obtained by subtracting the components of the leakage signal obtained by the above measurement from the first sound signal is not strictly equal to the actual environmental noise signal, but is approximately equal to the actual environmental noise signal. Therefore, in this application, the reduction result is referred to as a quasi-environmental noise signal.
  • the quasi-environmental noise signal can be understood as a compensation signal obtained by leakage compensation of the first sound signal.
  • FIG5 shows a schematic diagram of an active noise reduction principle of an acoustic device provided according to an embodiment of this specification. As shown in FIG5 , it is assumed that:
  • the transfer function between the sound emitted by the noise source 300 and the audio signal measured by the first sound sensor module 103 is denoted as h1;
  • the transfer function between the sound emitted by the noise source 300 and the audio signal measured by the second sound sensor module 104 is denoted as h2;
  • the transfer function between the sound emitted by the speaker 102 and the audio signal measured by the first sound sensor module 103 is denoted as h3;
  • the transfer function between the sound emitted by the speaker 102 and the audio signal measured by the second sound sensor module 104 is denoted as h4;
  • the transfer function between the input and output of the feedforward filter is denoted as h5;
  • the transfer function between the input and output of the feedback filter is denoted as h6;
  • the acoustic transfer function between the sound emitted by the speaker 102 and the eardrum 202 is recorded as h7;
  • the acoustic transfer function between the sound emitted by the noise source 300 and the eardrum 202 is recorded as h8.
  • the environmental noise emitted by the noise source 300 is recorded as S0; the first sound signal collected by the first sound sensor module 103 is recorded as S1; the second sound signal collected by the second sound sensor module 104 is recorded as S2; the noise cancellation signal emitted by the speaker 102 is recorded as S3; and the environmental noise at the eardrum 202 is recorded as S4.
  • S4 refers to the environmental noise actually heard by the human ear, that is, the environmental noise remaining at the eardrum 202 after the noise reduction process.
  • the above formula (1-1) corresponds to the feedforward noise reduction mode
  • the above formula (1-2) corresponds to the feedback noise reduction mode
  • the above formula (1-3) corresponds to the hybrid noise reduction mode.
  • the following takes the feedforward noise reduction mode as an example to analyze the design principle of the feedforward filter h5.
  • the noise reduction target of active noise reduction technology is to minimize S4.
  • the first sound sensor module can be called an ideal feedforward sound sensor module
  • the feedforward filter can be called an ideal feedforward filter.
  • the noise reduction circuit 105 can measure the transfer function h3′ between the speaker 102 and the first sound sensor module 103 by means of internal model control, wherein h3′ ⁇ h3.
  • the transfer function h3′ can also be referred to as the measured transfer function.
  • the noise reduction circuit 105 can use h3′ to compensate for the first sound signal to obtain a quasi-ambient noise signal.
  • the noise reduction circuit 105 can filter the quasi-ambient noise signal through an ideal feedforward filter to obtain a first noise reduction signal.
  • h3′ can be measured in the following manner: the noise reduction circuit 105 sends a test audio signal to the speaker 102 so that the speaker 102 emits a corresponding test audio, and the test audio is collected by the first sound sensor module 103.
  • the noise reduction circuit 105 can perform the above measurement process when it detects that the acoustic device 100 is turned on or when it detects that the acoustic device 100 is worn by the user, thereby improving the accuracy of h3′.
  • the noise reduction circuit 105 may input the quasi-environmental noise signal S1′ into a feedforward filter (h5), and filter the quasi-environmental noise signal (S1′) through the feedforward filter to obtain a first noise reduction signal.
  • the feedforward filter is configured to adjust at least one of the gain or phase of the quasi-environmental noise signal (S1′) so that the obtained first noise reduction signal can offset at least part of the environmental noise at the eardrum 202 and/or in the surrounding space.
  • the above-mentioned feedforward filter can be an ideal feedforward filter, that is, the ideal amplitude-phase response of the above-mentioned feedforward filter can be designed based on formula (6).
  • S14 Sending the first noise cancellation signal to a speaker, so that the speaker converts the first noise cancellation signal into a first noise cancellation audio to reduce the volume of the ambient noise at the eardrum.
  • the noise reduction circuit 105 is in communication connection with the speaker 102. After generating the first noise reduction signal, the noise reduction circuit 105 may send the first noise reduction signal to the speaker 102. In this way, the speaker 102 plays the first noise reduction audio corresponding to the first noise reduction signal, so that the first noise reduction audio and the ambient noise at the eardrum 202 are offset or partially offset, thereby achieving the purpose of noise reduction.
  • FIG6 shows a schematic diagram of the noise reduction effect of an active noise reduction method provided according to an embodiment of the present specification.
  • curves 601 and 602 correspond to the noise reduction results of two test scenarios, respectively.
  • the test process corresponding to curve 601 is as follows: the noise reduction circuit 105 obtains the first sound signal collected by FF1 in FIG3 (located at the acoustic zero point of the speaker 102), and the first sound signal does not contain or substantially does not contain a leakage signal from the speaker 102).
  • the noise reduction circuit 105 uses an ideal feedforward filter to perform feedforward noise reduction based on the first sound signal to obtain the noise reduction result shown in curve 601.
  • the test process corresponding to curve 602 is as follows: the noise reduction circuit 105 obtains the first sound signal collected by FF3 in FIG3 (not located at the acoustic zero point of the speaker 102, or located outside the acoustic zero point of the speaker 102), and the first sound signal contains a leakage signal from the speaker 102.
  • the noise reduction circuit 105 adopts the active noise reduction method shown in FIG4, first reducing the leakage signal component in the first sound signal to obtain a quasi-environmental noise signal, and then adopts an ideal feedforward filter to perform feedforward noise reduction based on the quasi-environmental noise signal.
  • the two noise reduction results of curve 601 and curve 602 are basically the same.
  • the noise reduction circuit 105 can effectively improve the noise reduction effect of the open acoustic device by first reducing the leakage signal component in the first sound signal to obtain a quasi-environmental noise signal, and then generating a first noise cancellation signal based on the quasi-environmental noise signal.
  • the noise reduction circuit 105 after the noise reduction circuit 105 obtains the first sound signal from the first sound sensor module, it first reduces the leakage signal component from the first sound signal to generate a quasi-environmental noise signal, and then performs feedforward noise reduction based on the quasi-environmental noise signal to generate a first noise reduction signal.
  • the noise reduction circuit 105 can interchange the above-mentioned reduction steps and the feedforward noise reduction steps. Specifically, after the noise reduction circuit 105 obtains the first sound signal (S1) from the first sound sensor module, it first performs feedforward noise reduction (h5) on the first sound signal to generate an intermediate noise reduction signal (S1*h5).
  • the noise reduction circuit 105 since the first sound signal includes an environmental noise signal and a leakage signal, when the noise reduction circuit 105 performs feedforward noise reduction on the first sound signal, it will simultaneously perform feedforward noise reduction on the environmental noise signal and the leakage signal, so that the intermediate noise reduction signal (S1*h5) obtained includes both the feedforward noise reduction result of the environmental noise signal and the feedforward noise reduction result of the leakage signal.
  • the feedforward noise reduction result of the leakage signal can be estimated in the following way: obtain the input signal (S3) corresponding to the speaker, provide the first gain (h3′) to the input signal to obtain the first gain signal (S3*h3′), it should be understood that the first gain signal S3*h3′ can be regarded as the estimated value of the leakage signal.
  • the first gain signal (S3*h3′) is filtered based on the feedforward noise reduction parameter (h5) to obtain the filtering result (S3*h3′*h5) of the leakage signal. Further, the noise reduction circuit 105 subtracts the feedforward noise reduction result (S3*h3′*h5) of the leakage signal from the intermediate noise reduction signal (S1*h5) to obtain the first noise reduction signal (S1*h5-S3*h3′*h5).
  • h3′ is the transfer function between the speaker and the first sound sensor module. Its measurement method can refer to the description of the relevant content in the previous text, which will not be repeated here.
  • the noise reduction circuit 105 can generate a quasi-environmental noise signal by first reducing the leakage signal component in the first sound signal, and then generate a first noise cancellation signal based on the quasi-environmental noise signal, and then convert the first noise cancellation signal into a first noise cancellation frequency through a speaker, thereby achieving the purpose of noise reduction. Since the noise reduction circuit 105 reduces the leakage signal component in the first sound signal during the feedforward noise reduction process, the influence of the leakage signal on the feedforward noise reduction is reduced, and therefore, the noise reduction effect of the active noise reduction can be improved.
  • the noise reduction circuit 105 should design/adjust the noise reduction parameters of the noise reduction circuit 105 with "minimizing the ambient noise (S4) at the eardrum 202" as the noise reduction target.
  • the second sound signal (S2) collected by the second sound sensor module 104 is equal to or approximately equal to the ambient noise (S4) at the eardrum 202. Therefore, in a closed acoustic device, "minimizing the second sound signal (S2)" can be used as a noise reduction target.
  • the second sound signal (S2) measured by the second sound sensor module 104 and the ambient noise (S4) at the eardrum 202 are no longer equal or approximately equal.
  • the reason why S2 and S4 are no longer equal or approximately equal is as follows: in combination with the acoustic transmission process shown in FIG. 5 , the second sound signal (S2) measured by the second sound sensor module 104 can be expressed as formula (3), and the ambient noise (S4) at the eardrum 202 can be expressed as formula (0), as follows:
  • both S2 and S4 can be regarded as mixed signals of two sound signals, wherein the first sound signal comes from the noise cancellation signal (S3) emitted by the speaker 102, and the second sound signal comes from the ambient noise signal (S0) emitted by the noise source 300.
  • S3 noise cancellation signal
  • S0 ambient noise signal
  • the transfer function (h2) between the sound emitted by the noise source 300 and the audio signal measured by the second sound sensor module 104 is equal to or approximately equal to the transfer function (h8) between the sound emitted by the noise source 300 and the eardrum 202, that is, h2 ⁇ h8, therefore, the components of the second sound signal in S2 and S4 are equivalent, and the difference between S2 and S4 mainly comes from: the difference between the component (S3*h4) of the noise cancellation signal in S2 and the component (S3*h7) of the noise cancellation signal in S4.
  • the transfer function (h4) between the sound emitted by the speaker 102 and the audio signal measured by the second sound sensor module 104 is equal to or approximately equal to the transfer function (h7) between the sound emitted by the speaker 102 and the eardrum 202, that is, h4 ⁇ h7. Therefore, S2 obtained based on formula (3) and S4 obtained based on formula (0) are also equal to or approximately equal to each other.
  • the transfer function (h4) between the sound emitted by the speaker 102 and the audio signal measured by the second sound sensor module 104 is no longer equal to or approximately equal to the transfer function (h7) between the sound emitted by the speaker 102 and the eardrum 202. Therefore, S2 obtained based on formula (3) and S4 obtained based on formula (0) are no longer equal to or approximately equal to each other.
  • the inventors of the present application proposed the following technical concept during the research process: by specially designing the structure of the acoustic device 100 and the position of each component, it is made so that: although S4 is not equal to S2, S4 can be estimated based on S2 (or S4 and S2 have the same change trend). In this way, S4 can be estimated based on S2, and active noise reduction can be performed with minimizing S4 as the noise reduction target, or the noise reduction parameters required for "minimizing S4 as the noise reduction target” can be derived based on the noise reduction parameters required for "minimizing S2 as the noise reduction target", thereby improving the active noise reduction effect.
  • the difference between S4 and S2 mainly comes from: the difference between the component of the noise reduction signal in S2 (S3*h4) and the component of the noise reduction signal in S4 (S3*h7). If you want to estimate S4 based on S2, the general consideration is that you need to know h4 and h7 respectively.
  • h7 and h4 are both quantities that are strongly related to the posture of the acoustic device 100, that is, when different users wear the acoustic device, h4 is different from each other, and h7 is also different from each other, and even when the same user wears the acoustic device multiple times, h4 is also different from each other, and h7 is also different from each other.
  • h7 since there is no acoustic sensor at the user's eardrum 202 in actual application scenarios, it is difficult to measure h7, which causes great difficulties in estimating S4.
  • the positions of the second sound sensor module 104 and the speaker 102 can be designed so that: h4 and h7 satisfy the first preset relationship, and the first preset relationship is independent of the posture of the acoustic device 100.
  • the first preset relationship is independent of the posture of the acoustic device 100, which means that no matter in what posture the acoustic device 100 is worn by the user, the first preset relationship is satisfied between h4 and h7.
  • the first preset relationship is satisfied between h4 and h7.
  • the first preset relationship is satisfied between h4 and h7.
  • the first preset relationship is satisfied between h4 and h7.
  • the present application does not limit the specific form of the first preset relationship.
  • the first preset relationship between h4 and h7 can be obtained by testing a large number of users wearing the acoustic device multiple times.
  • the present application does not limit the specific positions of the second sound sensor module 104 and the speaker 102, as long as the positions of the two can satisfy the first preset relationship between h4 and h7, and the first preset relationship is independent of the position of the acoustic device 100.
  • the speaker 102 can be set at a position close to the ear canal opening, and the sound output surface (i.e., the surface where the sound output end is located) faces the ear canal opening.
  • the speaker 102 can be set at this position.
  • the second sound sensor module 104 can be set on the sound output surface of the speaker 102.
  • the following principles can be considered: (1) the sound collection end of the second sound sensor module 104 is away from the user's skin, and (2) the sound collection end of the second sound sensor module 104 is as close to the ear canal opening as possible.
  • the positions of the speaker 102 and the second sound sensor module 104 determined in the above manner can make h4 and h7 less susceptible to the influence of the wearing posture, that is, no matter in which posture the acoustic device 100 is worn, h4 and h7 satisfy the same first preset relationship.
  • the positions of the speaker 102 and the second sound sensor module 104 determined in the above manner can also make the second sound signal S2 collected by the second sound sensor module 104 closer to the ambient noise S4 at the eardrum 202, and the second sound signal S2 is less susceptible to the influence of skin reflection, so that S4 estimated based on the first preset relationship and the second sound signal S2 is more accurate.
  • the present application provides an active noise reduction method P200, which can adjust the noise reduction parameters based on the second sound signal (S2) and the first preset relationship regardless of the position in which the acoustic device 100 is worn by the user, thereby improving the active noise reduction effect.
  • the active noise reduction method P200 can be independently applied to the acoustic device 100 provided in the present application, or it can be combined with other active noise reduction methods described in other parts of this article.
  • FIG7 shows a flow chart of another active noise reduction method P200 provided according to an embodiment of the present specification.
  • the active noise reduction method P200 may be executed by the noise reduction circuit 105 in the acoustic device 100.
  • the processor 107 in the noise reduction circuit 105 may read an instruction set stored in its local storage medium, and then execute the active noise reduction method P200 described in the present specification according to the instruction set.
  • the active noise reduction method P200 may include:
  • S21 Acquire a second sound signal from a second sound sensor module.
  • the noise reduction circuit 105 may determine the ambient noise (S4) at the eardrum 202 based on the second sound signal (S2) and the first preset relationship. Then, the noise reduction circuit 105 adjusts the noise reduction parameters with the goal of minimizing the ambient noise (S4) at the eardrum 202.
  • the noise reduction circuit 105 may estimate S4 in the following manner:
  • a first transfer function h4′ between the sound emitted by the speaker 102 and the audio signal measured by the second sound sensor module 104 is measured.
  • h4′ can be measured in the following manner: the noise reduction circuit 105 sends a test audio signal to the speaker 102 so that the speaker 102 emits a corresponding test audio, and the test audio is collected by the second sound sensor module 104.
  • This implementation method of measuring h4′ is simple and will not affect the noise reduction performance of the noise reduction circuit 105.
  • h4 is usually related to the wearing posture of the acoustic device 100
  • the corresponding h4 may be different, and when the same acoustic device is worn by the same user multiple times, the corresponding h4 may also be different. Therefore, the noise reduction circuit 105 can perform the above measurement process when it is detected that the acoustic device 100 is turned on, or when it is detected that the acoustic device 100 is worn by the user, thereby improving the accuracy of h4′.
  • a second transfer function h7 ′ between the sound emitted by the speaker 102 and the eardrum 202 may be determined.
  • S4 can be determined based on the first transfer function h4′, the second transfer function h7′ and S2, as follows:
  • the component of the ambient noise in S2 (S0*h2) is approximately equal to the component of the ambient noise in S4 (S0*h8), that is:
  • S3 is the input signal of the speaker 102
  • h4 can be replaced by the first transfer function h4′
  • h7 can be replaced by the second transfer function h7′
  • S2 is the second sound signal collected by the second sound sensor module 104. It can be seen that the noise reduction circuit 105 can estimate S4 based on the first transfer function h4′, the second transfer function h7′, the second sound signal S2, and the input signal S3 of the speaker 102.
  • the above-mentioned active noise reduction process first determines the ambient noise (S4) at the eardrum 202 based on the second sound signal (S2) and the first preset relationship, and then minimizes the ambient noise (S4) at the eardrum 202 as the noise reduction target, thereby improving the accuracy of the noise reduction target, thereby improving the effect of active noise reduction.
  • the above embodiment is based on the following assumption when determining S4: the transfer function (h2) between the sound emitted by the noise source 300 and the audio signal measured by the second sound sensor module 104 is approximately equal to the transfer function (h8) between the sound emitted by the noise source 300 and the eardrum 202, that is, h2 ⁇ h8.
  • the inventor takes into account that in actual application scenarios, h2 and h8 are usually not strictly equal, which leads to a certain error in S4 determined by the above embodiment. Therefore, in order to further improve the accuracy of S4, h2 and h8 can also be considered in the process of determining S4. However, h2 and h8 are also quantities related to the posture of the acoustic device 100.
  • h2 When different users wear the acoustic device, h2 is different from each other, h8 is different from each other, and even when the same user wears the acoustic device multiple times, h2 is also different from each other, and h8 is also different from each other. Therefore, it is difficult to measure h2 and h8 separately.
  • the second preset relationship can also be satisfied between h2 and h8, and the second preset relationship is also independent of the posture of the acoustic device 100.
  • the second preset relationship is independent of the posture of the acoustic device 100, which means that no matter in what posture the acoustic device 100 is worn by the user, the second preset relationship is satisfied between h2 and h8. For example, when the acoustic device 100 is worn by different users, the second preset relationship is satisfied between h2 and h8. For another example, when the acoustic device 100 is worn by the same user multiple times, the second preset relationship is satisfied between h2 and h8.
  • the present application does not limit the specific form of the second preset relationship.
  • the relationship between h2/h1 and h8/h1 can be obtained by testing a large number of users and wearing the acoustic device multiple times, and the second preset relationship between h2 and h8 can be obtained based on the relationship.
  • S4 can be estimated based on the first preset relationship, the second preset relationship, and S2.
  • the specific method is as follows:
  • the measurement process of the first transfer function h4′ can refer to the description of the related content above, which will not be repeated here.
  • a second transfer function h7' between the sound emitted by the speaker 102 and the eardrum 202 can be determined.
  • the determination process of the second transfer function h7' can refer to the description of the related content above, which will not be repeated here.
  • S4 may be determined based on the second preset relationship, the first transfer function h4′, the second transfer function h7′ and S2, as follows:
  • S3 is the input signal of the speaker 102
  • h4 can be replaced by the first transfer function h4'
  • h7 can be replaced by the second transfer function h7'
  • S2 is the second sound signal collected by the second sound sensor module 104
  • h10 can be obtained based on the second preset relationship. It can be seen that based on the first transfer function h4', the second transfer function h7', the second preset relationship, the second sound signal S2, and the input signal S3 of the speaker 102, S4 can be determined.
  • the noise reduction parameters of the noise reduction circuit 105 can be adjusted with minimizing S4 as the noise reduction target.
  • the noise reduction circuit 105 may include a feedforward filter, in which case the above-mentioned noise reduction parameters may include filtering parameters of the feedforward filter.
  • the noise reduction circuit 105 may include a feedback filter, in which case the above-mentioned noise reduction parameters may include filtering parameters of the feedback filter.
  • the noise reduction circuit 105 may include a feedforward filter and a feedback filter, in which case the above-mentioned noise reduction parameters may include at least one of the filtering parameters of the feedforward filter or the filtering parameters of the feedback filter.
  • the filter parameters of the feedforward filter or feedback filter may include at least one of: filter gain, filter phase, or quality factor.
  • the noise reduction parameters of the noise reduction circuit 105 may include the filter gain of the feedforward filter.
  • the filter gain of the feedforward filter required for "minimizing the second sound signal (S2) as the noise reduction target” is referred to as the first filter gain
  • the filter gain of the feedforward filter required for "minimizing the ambient noise (S4) at the eardrum 202 as the noise reduction target” is referred to as the second filter gain.
  • FIG8A shows a schematic diagram of a frequency response curve of feedforward noise reduction of the ambient noise at the eardrum using different feedforward filter gains when the first user wears the acoustic device.
  • FIG8B shows a schematic diagram of a frequency response curve of feedforward noise reduction of the second sound signal using different feedforward filter gains when the first user wears the acoustic device. It is assumed that when the first preset relationship is satisfied between h4 and h7, the second sound signal (S2) is 2dB lower than the intensity of the ambient noise (S4) at the eardrum 202.
  • the feedforward filter in the noise reduction circuit 105 uses different filter gains (increasing from 0dB to 4dB in sequence) to perform active noise reduction.
  • the frequency response curve obtained by performing feedforward noise reduction based on the ambient noise (S4) at the eardrum 202 is shown in Figure 8A.
  • the frequency response curve obtained by performing feedforward noise reduction based on the second sound signal (S2) is shown in Figure 8B. It can be seen from Figure 8A that if minimizing the ambient noise (S4) at the eardrum 202 is used as the noise reduction target, the second filter gain required for the feedforward filter is 4dB. It can be seen from Figure 8B that if minimizing the second sound signal (S2) is used as the noise reduction target, the first filter gain required for the feedforward filter is 2dB.
  • FIG9A is a schematic diagram showing a frequency response curve of feedforward noise reduction of the ambient noise at the eardrum using different feedforward filter gains when the second user wears the acoustic device.
  • FIG9B is a schematic diagram showing a frequency response curve of feedforward noise reduction of the second sound signal using different feedforward filter gains when user B wears the acoustic device. It is assumed that the second sound signal (S2) is 2 dB lower than the intensity of the ambient noise (S4) at the eardrum 202 when the first preset relationship is satisfied between h4 and h7.
  • the feedforward filter in the noise reduction circuit 105 uses different filter gains (increasing from 0dB to 4dB in sequence) to perform active noise reduction.
  • the frequency response curve obtained by feedforward noise reduction based on the ambient noise (S4) at the eardrum 202 is shown in Figure 9A.
  • the frequency response curve obtained by feedforward noise reduction based on the second sound signal (S2) is shown in Figure 9B. It can be seen from Figure 9A that if minimizing the ambient noise (S4) at the eardrum 202 is used as the noise reduction target, the second filter gain required for the feedforward filter is 3dB. It can be seen from Figure 8B that if minimizing the second sound signal (S2) is used as the noise reduction target, the first filter gain required for the feedforward filter is 1dB.
  • the "relationship between the first filter gain and the second filter gain” is the same as the “relationship between the intensity of the second sound signal (S2) and the intensity of the ambient noise (S4) at the eardrum 202". That is, if the intensity of the second sound signal (S2) is xdB lower than the intensity of the ambient noise (S4) at the eardrum 202, the first filter gain is xdB lower than the second filter gain.
  • the noise reduction circuit 105 can also adjust the filter gain of the feedforward filter in the following manner: first, the first filter gain of the feedforward filter is determined by minimizing the second sound signal (S2) as the noise reduction target. Then, the noise reduction circuit 105 determines the above-mentioned second filter gain based on the first filter gain and the first preset relationship, and adjusts the current filter gain of the feedforward filter to the second filter gain. For example, assume that the first preset relationship makes the intensity of the second sound signal (S2) 2dB lower than the intensity of the ambient noise (S4) at the eardrum 202. The noise reduction circuit 105 first minimizes the second sound signal (S2) as the noise reduction target and determines that the first filter gain is 2dB. Then, the noise reduction circuit 105 can increase 2dB on the basis of the first filter gain to obtain a second filter gain of 4dB. Therefore, the current filter gain of the feedforward filter is adjusted to 4dB.
  • the acoustic device 100 may provide a plurality of working modes to the user, and the noise reduction circuit 105 corresponds to a default noise reduction parameter in each working mode, and the default noise reduction parameters corresponding to different working modes are different.
  • an interactive control may be provided on the acoustic device 100, and the user may switch different working modes by operating the interactive control.
  • the acoustic device 100 may provide an interactive interface, and the interactive interface may be presented on the screen of the acoustic device 100, or on a target device connected to the acoustic device 100 for communication. The user may select different working modes through the interactive interface. In some embodiments, the above-mentioned multiple working modes correspond to different types of environments respectively.
  • the user may indicate the type of environment in which the acoustic device 100 is currently located in an interactive manner, and the noise reduction circuit 105 may switch to the corresponding working mode based on the type of environment in which the user is currently located.
  • the above-mentioned multiple working modes may correspond to different user types respectively.
  • the user may indicate the type of user to which the user belongs to the acoustic device 100 in an interactive manner, and the noise reduction circuit 105 may switch to the corresponding working mode based on the type of user to which the user belongs.
  • the noise reduction circuit 105 can obtain the target working mode indicated by the user in the multiple working modes, and then adjust the default noise reduction parameters corresponding to the target working mode based on the second sound signal (S2) and the first preset relationship. It should be understood that the acoustic device 100 can meet the noise reduction needs of different users or in different environments by providing multiple working modes.
  • the noise reduction circuit 105 may also obtain a first sound signal from the first sound sensor module, and filter at least one of the first sound signal or the second sound signal based on the adjusted noise reduction parameter to generate a noise reduction signal. Furthermore, the noise reduction circuit 105 sends the noise reduction signal to the speaker so that the speaker converts the noise reduction signal into a noise reduction frequency to reduce the volume of the ambient noise at the eardrum.
  • the noise reduction circuit 105 can filter the first sound signal based on the adjusted noise reduction parameters to generate a noise reduction signal. For example, the noise reduction circuit 105 can input the first sound signal into the feedforward filter, filter the first sound signal through the feedforward filter, and obtain the noise reduction signal. In some embodiments, when the first sound signal includes both the ambient noise signal and the leakage signal, the noise reduction circuit 105 can first generate a quasi-ambient noise signal by reducing the component of the leakage signal in the first sound signal, and then filter the quasi-ambient noise signal based on the adjusted noise reduction parameters to obtain the noise reduction signal.
  • the noise reduction circuit 105 may filter the second sound signal based on the adjusted noise reduction parameter to generate a noise reduction signal. For example, the noise reduction circuit 105 may input the second sound signal into the feedback filter, and filter the second sound signal through the feedback filter to obtain a noise reduction signal.
  • the noise reduction circuit 105 can filter the first sound signal based on the adjusted noise reduction parameters to obtain a first noise reduction signal. For example, the noise reduction circuit 105 inputs the first sound signal into a feedforward filter, and filters the first sound signal through the feedforward filter to obtain a first noise reduction signal. The noise reduction circuit 105 can also filter the second sound signal based on the adjusted noise reduction parameters to obtain a second noise reduction signal. For example, the noise reduction circuit 105 inputs the second sound signal into a feedback filter, and filters the second sound signal through the feedback filter to obtain a second noise reduction signal.
  • the noise reduction circuit 105 synthesizes the first noise reduction signal and the second noise reduction signal to obtain a noise reduction signal.
  • the noise reduction circuit 105 can first generate a quasi-ambient noise signal by reducing the component of the leakage signal in the first sound signal, and then filter the quasi-ambient noise signal based on the adjusted noise reduction parameters to obtain a first noise reduction signal.
  • active noise reduction based on the adjusted noise reduction parameters can improve the effect of active noise reduction.
  • by reducing the leakage signal component in the first sound signal the influence of the leakage signal on the feedforward noise reduction process is reduced, which can further improve the effect of active noise reduction.
  • the noise reduction circuit 105 can adjust the noise reduction parameters based on the second sound signal (S2) and the first preset relationship, and perform active noise reduction based on the adjusted noise reduction parameters. Since the noise reduction circuit 105 adjusts the noise reduction parameters based on the second sound signal (S2) and the first preset relationship, the adjusted noise reduction parameters meet the most essential noise reduction goals, thereby improving the noise reduction effect of active noise reduction.
  • the first sound sensor module 103 may include a sound sensor.
  • the ambient noise since the ambient noise may come from any direction, the following situation may occur: the ambient noise has reached the speaker 102 or the eardrum 202 before reaching the sound sensor.
  • the sound sensor is arranged on the first side of the acoustic device 100 (for example, the side facing the front of the user), and the noise source 300 is located on the second side of the acoustic device 100 (for example, the side facing the back of the user)
  • the sound sensor is far away from the noise source 300, the ambient noise emitted by the noise source 300 first reaches the speaker 102 or the eardrum 202, and then is collected by the sound sensor.
  • the causality of the feedforward noise reduction performed by the noise reduction circuit 105 deteriorates, so that the noise reduction effect of the feedforward noise reduction deteriorates, especially the feedforward noise reduction effect of certain frequency bands (for example, the mid-high frequency band) deteriorates, and may even cause the noise heard by the human ear to increase.
  • the first sound sensor module 103 may include multiple sound sensors.
  • the number of sound sensors included in the first sound sensor module 103 is recorded as N, where N is an integer greater than or equal to 2.
  • the N sound sensors are physically connected to the support 101, respectively, and are distributed on a side away from the eardrum relative to the speaker 102.
  • each sound sensor is configured to collect ambient noise from the noise source 300 and generate an ambient noise signal.
  • the ambient noise signal collected by each sound sensor is referred to as an individual ambient noise signal, and the ambient noise signal collected by the first sound sensor module 103 is referred to as a comprehensive ambient noise signal.
  • the N sound sensors have different directions relative to the target point on the speaker 102.
  • the target point may be the center point or the sound output point of the speaker 102. Since the N sound sensors have different directions relative to the target point, when the ambient noise comes from different directions, at least one of the N sound sensors can collect the ambient noise before the speaker 102.
  • FIG. 10 shows a schematic diagram of the distribution of each sound sensor when the first sound sensor module includes two sound sensors.
  • the first sound sensor module 103 may include: a sound sensor 1031 and a sound sensor 1032.
  • the two sound sensors may be located on two sides of the acoustic device 100 facing opposite directions, or in other words, the two sound sensors are in opposite directions relative to the target point.
  • the sound sensor 1031 is located on the first side of the acoustic device 100 facing the front of the user
  • the sound sensor 1032 is located on the second side of the acoustic device 100 facing the rear of the user.
  • the phase of the ambient noise reaching the sound sensor 1031 (or the phase of the individual ambient noise signal measured by the sound sensor 1031) is ahead of the phase of the ambient noise reaching the sound output end of the speaker 102.
  • the phase of the ambient noise reaching the sound sensor 1032 (or the phase of the individual ambient noise signal measured by the sound sensor 1032) is ahead of the phase of the ambient noise reaching the sound output end of the speaker 102.
  • the two sound sensors may be located at the acoustic zero point of the speaker 102. In this way, the signals collected by the two sound sensors do not contain leakage signals from the speaker 102, thereby improving the active noise reduction effect.
  • FIG. 11 shows a schematic diagram of the distribution of each sound sensor when the first sound sensor module includes three sound sensors.
  • the first sound sensor module 103 may include: a sound sensor 1031, a sound sensor 1032, and a sound sensor 1033.
  • the above three sound sensors can be distributed on three sides of the acoustic device 100 facing different directions.
  • the sound sensor 1031 is located on the first side of the acoustic device 100 facing the front of the user, the sound sensor 1032 is located on the second side of the acoustic device 100 facing the back of the user, and the sound sensor 1033 is located on the third side of the acoustic device 100 facing the ground.
  • the phase of the ambient noise reaching the sound sensor 1031 is ahead of the phase of the ambient noise reaching the sound output end of the speaker 102.
  • the phase of the ambient noise reaching the sound sensor 1032 (or the phase of the individual ambient noise signal measured by the sound sensor 1032) is ahead of the phase of the ambient noise reaching the sound output end of the speaker 102.
  • the phase of the ambient noise reaching the sound sensor 1033 (or the phase of the individual ambient noise signal measured by the sound sensor 1033) is ahead of the phase of the ambient noise reaching the sound output end of the speaker 102.
  • the above three sound sensors can be distributed in the form of a triangle at the acoustic zero point position of the speaker 102. In this way, the signals collected by the three sound sensors do not contain leakage signals from the speaker 102, thereby improving the active noise reduction effect.
  • FIG. 10 and FIG. 11 are only two possible distribution modes.
  • the N sound sensors may also adopt other distribution modes, which are not illustrated one by one in this article.
  • this application does not specifically limit the value of N, for example, the value of N may also be equal to 4, 5 or any other integer.
  • the N sound sensors may be arranged in an array, for example, a linear array, a planar array, a spherical array or other arrays, etc. Arranging in an array is also beneficial to reducing the complexity of signal processing inside the noise reduction circuit 105, thereby improving the active noise reduction performance.
  • At least some of the N sound sensors may be omnidirectional microphones. Omnidirectional microphones have high sensitivity to ambient noise in all directions and can collect ambient noise in any direction. At least some of the N sound sensors may also be directional microphones. Directional microphones can only collect ambient noise in a specified direction. For example, as shown in FIG10 , the directivity of the sound sensor 1031 may be in front of the user and is configured to collect ambient noise from the front of the user, and the directivity of the sound sensor 1032 may be behind the user and is configured to collect ambient noise from the rear of the user.
  • the above-mentioned directional microphones may include, but are not limited to: cardioid directional microphones, near-cardioid directional microphones, or other directional microphones. The directivities of the above-mentioned directional microphones for different frequencies may be the same or different.
  • the present application provides an active noise reduction method P300.
  • the noise reduction circuit 105 performs active noise reduction, weights can be assigned to the N sound sensors, so that the first sound sensor module 103 has phase leading in any direction. This scheme improves the causality of feedforward noise reduction, thereby improving the active noise reduction effect.
  • the active noise reduction method P300 can be independently applied to the acoustic device 100 provided in the present application, and can also be combined with other active noise reduction methods described in other parts of this document.
  • FIG12 shows a flow chart of another active noise reduction method P300 provided according to an embodiment of the present specification.
  • the active noise reduction method P300 may be executed by the noise reduction circuit 105 in the acoustic device 100.
  • the processor 107 in the noise reduction circuit 105 may read the instruction set stored in its local storage medium, and then execute the active noise reduction method P300 described in the present specification according to the instruction set.
  • the active noise reduction method P300 may include:
  • the target direction refers to the direction from which the ambient noise comes, that is, the direction of the noise source 300.
  • the direction of the ray pointing from the target point on the speaker 102 to the noise source 300 may be referred to as the target direction.
  • the noise reduction circuit 105 can obtain N individual environmental noise signals collected by N sound sensors, and estimate the target direction from which the environmental noise comes based on the N individual environmental noise signals. In some embodiments, the noise reduction circuit 105 can obtain the target direction by performing a full-band Direction of Arrival (DOA) analysis on the N individual environmental noise signals. In this case, the target direction represents the direction of arrival of the full-band environmental noise (i.e., the overall environmental noise).
  • DOA Direction of Arrival
  • DOA Estimating Signal Parameter via Rotational Invariance Techniques
  • MUSIC Multiple Signal Classification
  • the comprehensive environmental noise signal is a signal obtained by weighted summing N individual environmental noise signals collected by N sound sensors based on the N weights.
  • the first sound sensor module 103 includes a sound sensor 1031 and a sound sensor 1032 .
  • the individual environmental noise signal collected by the sound sensor 1031 is:
  • the individual environmental noise signal collected by the sound sensor 1032 is:
  • the comprehensive environmental noise signal measured by the first sound sensor module 103 based on the above two weights can be expressed as:
  • phase of the above comprehensive environmental noise signal can be expressed as:
  • the noise reduction circuit 105 can set weights for the N sound sensors respectively based on the target direction, so that the phase of the above-mentioned integrated noise signal is ahead of the phase of the ambient noise reaching the sound output end of the speaker 102.
  • the weight corresponding to the ith sound sensor is related to the leading condition of the phase of the individual environmental noise signal collected by the ith sound sensor. For example, the more the phase of the individual environmental noise signal collected by the ith sound sensor is ahead of the phase of the environmental noise reaching the sound output end of the speaker 102, the greater the weight corresponding to the ith sound sensor, and vice versa, the smaller the weight corresponding to the ith sound sensor.
  • i is any positive integer less than or equal to N.
  • the weight corresponding to the i-th sound sensor is negatively correlated with ⁇ i . That is, the smaller ⁇ i is (indicating that the deviation between the direction of the sound sensor relative to the target point and the target direction is smaller), the greater the weight is, and the larger ⁇ i is (indicating that the deviation between the direction of the sound sensor relative to the target point and the target direction is larger), the smaller the weight is.
  • i is any positive integer less than or equal to N.
  • the weight of the sound sensor 1031 is greater than the weight of the sound sensor 1032. In this way, when active noise reduction is performed, the sound sensor 1031 plays a major role and can ensure phase leadership. Assume that the ambient noise comes from the back of the user, the weight of the sound sensor 1032 is greater than the weight of the sound sensor 1031. In this way, when active noise reduction is performed, the sound sensor 1032 plays a major role and can also ensure phase leadership.
  • S33 Generate a first noise cancellation signal based on the N individual environmental noise signals collected by the N sound sensors and the N weights.
  • the noise reduction circuit 105 may include N feedforward filters, corresponding to the N sound sensors one by one.
  • the i-th feedforward filter is connected to the i-th sound sensor and the speaker 102, and is configured to filter the individual environmental noise signal collected by the i-th sound sensor.
  • the i is any positive integer less than or equal to N. That is, the N feedforward filters in the noise reduction circuit 105 are in parallel.
  • the N feedforward filters are in parallel, the order of the filter will not increase, nor will the delay increase, during the active noise reduction process.
  • the N feedforward filters in parallel can also help increase the filtering complexity.
  • the N feedforward filters can be responsible for noise reduction in different frequency bands, thereby enhancing the feedforward noise reduction capability.
  • FIG13 shows a schematic diagram of the active noise reduction principle of another acoustic device provided according to an embodiment of the present specification.
  • the first sound sensor module 103 includes a sound sensor 1031 and a sound sensor 1032
  • the noise reduction circuit includes a feedforward filter h51 and a feedforward filter h52.
  • the feedforward filter h51 connects the sound sensor 1031 and the speaker 102
  • the feedforward filter h52 connects the sound sensor 1032 and the speaker 102.
  • the transfer function between the sound emitted by the noise source 300 and the audio signal measured by the sound sensor 1031 is denoted as h11;
  • the transfer function between the sound emitted by the noise source 300 and the audio signal measured by the sound sensor 1032 is denoted as h12;
  • the acoustic transfer function from the sound emitted by the speaker 102 to the eardrum 202 is denoted as h7;
  • the acoustic transfer function between the sound emitted by the noise source 300 and the eardrum 202 is denoted as h8.
  • the noise signal emitted by the noise source 300 is recorded as S0; the individual environmental noise signal collected by the sound sensor 1031 is recorded as S11; the individual environmental noise signal collected by the sound sensor 1032 is recorded as S12; the noise cancellation signal emitted by the speaker 102 is recorded as S3; and the noise signal received by the eardrum 202 is recorded as S4.
  • the filtering parameters of the feedforward filter h51 can be adjusted based on the weight of the sound sensor 1031, and the individual environmental noise signal S11 collected by the sound sensor 1031 can be filtered through the adjusted feedforward filter h51 to generate an individual noise reduction signal.
  • the noise reduction circuit 105 can also adjust the filtering parameters of the feedforward filter h52 based on the weight of the sound sensor 1032, and the individual environmental noise signal S12 collected by the sound sensor 1032 can be filtered through the adjusted feedforward filter h52 to generate an individual noise reduction signal.
  • the noise reduction circuit 105 synthesizes the two individual noise reduction signals generated by the two feedforward filters to obtain a first noise reduction signal.
  • the above adjustment of the filter parameters of the feedforward filter h51 or the feedforward filter h52 may include: adjusting the filter gain of the feedforward filter h51 or the feedforward filter h52.
  • the weight of the sound sensor 1031 may be multiplied by the current filter gain of the feedforward filter h51 to obtain the adjusted filter gain of the feedforward filter h51.
  • the weight of the sound sensor 1032 may be multiplied by the current filter gain of the feedforward filter h52 to obtain the adjusted filter gain of the feedforward filter h52.
  • the noise reduction circuit 105 adjusts the filtering parameters of N feedforward filters based on N weights, so that during the active noise reduction process, the sound sensors with higher weights (sound sensors with higher phase lead) and their corresponding feedforward filters contribute more to the overall noise reduction, while the sound sensors with lower weights (sound sensors with lower phase lead) and their corresponding feedforward filters contribute less to the overall noise reduction, thereby improving the active noise reduction effect.
  • the N sound sensors may be N directional microphones with different directivities.
  • the directivity of the sound sensor 1031 is in front of the user, and the directivity of the sound sensor 1032 is behind the user.
  • the directivities of the two sound sensors make h11 much larger than h12 (i.e., h11>>h12).
  • the sound sensor 1031 is mainly responsible for the active noise reduction process. Therefore, the first sound sensor module 103 has phase leading property, thereby improving the active noise reduction effect.
  • the directivities of the two sound sensors make h11 much smaller than h12 (i.e., h11 ⁇ h12).
  • the sound sensor 1032 is mainly responsible for the active noise reduction process. Therefore, the first sound sensor module 103 has phase leading property, thereby improving the active noise reduction effect.
  • the different directivities of the N sound sensors enable the active noise reduction process to automatically select the optimal sound sensor without adjusting the filtering parameters of the feedforward filter, thereby achieving the phase leading nature of the first sound sensor module in all directions.
  • S34 Sending the first noise cancellation signal to a speaker, so that the speaker converts the first noise cancellation signal into a first noise cancellation audio to reduce the volume of the ambient noise at the eardrum.
  • the noise reduction circuit 105 can also estimate the sub-band when estimating the target direction.
  • the full-band is divided into M sub-bands, and the environmental noise includes M sub-band noises corresponding to the M sub-bands.
  • the noise reduction circuit 105 can estimate the wave direction of the M sub-band noises for each sub-band.
  • the target direction obtained in S31 includes M wave directions corresponding to the M sub-bands. It should be noted that the present application does not limit the division method of the M sub-bands.
  • the above-mentioned M sub-bands may include: a low-frequency band (for example, 0 to 150 Hz), a mid-frequency band (for example, 150 to 500 Hz) and a high-frequency band (for example, 500 to 2000 Hz).
  • a low-frequency band for example, 0 to 150 Hz
  • a mid-frequency band for example, 150 to 500 Hz
  • a high-frequency band for example, 500 to 2000 Hz.
  • the noise reduction circuit 105 can obtain N individual environmental noise signals collected by N sound sensors, and then estimate the direction of arrival of the jth sub-band in the following manner: extract the sub-band noise signal corresponding to the jth sub-band from the N individual environmental noise signals, obtain N sub-band noise signals corresponding to the jth sub-band, and perform DOA analysis on the N sub-band noise signals to obtain the direction of arrival of the jth sub-band.
  • j is any positive integer less than or equal to M.
  • the noise reduction circuit 105 can perform active noise reduction based on each sub-band. Specifically, the noise reduction circuit 105 determines the N sub-band weights corresponding to the N sound sensors for the j-th sub-band based on the wave direction corresponding to the j-th sub-band, so that the phase of the comprehensive sub-band noise signal measured by the first sound sensor module 103 based on the above-mentioned N sub-band weights leads the phase of the environmental noise of the j-th sub-band reaching the sound output end of the speaker 102.
  • the comprehensive sub-band noise signal is a signal obtained by weighted summing the sub-band noise signals corresponding to the j-th sub-band collected by the N sound sensors based on the N sub-band weights. Further, the noise reduction circuit 105 generates N individual sub-band noise cancellation signals corresponding to the j-th sub-band based on the sub-band noise signals corresponding to the j-th sub-band collected by the N sound sensors and the N sub-band weights. The noise reduction circuit superimposes the N individual sub-band noise reduction signals to obtain a sub-band noise reduction signal corresponding to the jth sub-band. Wherein, j is any positive integer less than or equal to M.
  • the noise reduction circuit 105 performs the above process for the M sub-bands respectively to obtain M sub-band noise reduction signals corresponding to the M sub-bands. Further, the noise reduction circuit 105 sends the M sub-band noise reduction signals to the speaker 102, so that the speaker 102 converts the M sub-band noise reduction signals into noise reduction audio to reduce the volume of the ambient noise at the eardrum 202.
  • each feedforward filter may include M filter units corresponding to M sub-bands, and when performing active noise reduction for the j-th sub-band, the filter parameters corresponding to the j-th filter unit in the feedforward filter may be adjusted based on the weight, for example, the filter gain corresponding to the j-th filter unit may be adjusted.
  • FIG14 shows a schematic diagram of a set of frequency response curves provided according to an embodiment of the present specification.
  • curve 141 illustrates the frequency response of the acoustic device 100 using a single sound sensor FF1 and cooperating with a feedforward filter
  • curve 142 illustrates the frequency response of the acoustic device 100 using a single sound sensor FF2 and cooperating with a feedforward filter
  • curve 143 illustrates the frequency response of the acoustic device 100 using both the sound sensor FF1 and the sound sensor FF2 and cooperating with two parallel feedforward filters.
  • curves 141 and 142 illustrates the single sound sensor FF1 and the single sound sensor FF2 respectively have a noise reduction effect in different frequency bands.
  • curve 143 the combination of the sound sensor FF1 and the sound sensor FF2 can achieve a noise reduction effect in a wider frequency band and achieve a deeper noise reduction depth.
  • FIG. 15 shows a schematic diagram of another set of frequency response curves provided according to an embodiment of the present specification.
  • curve 153 illustrates the frequency response of the acoustic device 100 using both the sound sensor FF1 and the sound sensor FF2, and cooperating with two parallel feedforward filters for noise reduction.
  • curve 151 illustrates the frequency response of FF1 and its corresponding feedforward filter
  • curve 152 illustrates the frequency response of FF2 and its corresponding feedforward filter.
  • the feedforward filter gain required for each sound sensor is significantly less than the feedforward filter gain required when a single sound sensor is used to achieve the same filtering effect.
  • the reduction of the feedforward filter gain can reduce leakage, thereby avoiding the system divergence problem caused by leakage, and the noise increase problem caused by some users wearing acoustic devices.
  • the noise reduction circuit 105 can determine the N weights corresponding to the N sound sensors based on the target direction from which the ambient noise comes, so that the phase of the comprehensive ambient noise signal measured by the first sound sensor module 103 based on the N weights is ahead of the phase of the ambient noise reaching the sound output end of the speaker. Then, the noise reduction circuit 105 generates a first noise reduction signal based on the N individual ambient noise signals collected by the N sound sensors and the N weights, and sends the first noise reduction signal to the speaker 102.
  • the scheme introduces N sound sensors and assigns weights to the N sound sensors, so that no matter which direction the ambient noise comes from, the first sound sensor module 103 can be guaranteed to have a phase leading property relative to the sound output end of the speaker 102, thereby improving the causality of the feedforward noise reduction, thereby improving the active noise reduction effect, and especially improving the high-frequency noise reduction performance.
  • the use of multiple sound sensors can also reduce the gain, thereby reducing the leakage of certain frequency bands (such as high frequencies) in open scenarios, thereby avoiding the system divergence problem caused by the leakage of the above frequency bands, and the noise increase problem caused by some users wearing acoustic devices.
  • this solution estimates the direction of the incoming waves at the granularity of sub-bands and performs active noise reduction for each sub-band, which helps to improve the noise reduction depth of each sub-band, thereby further improving the effect of active noise reduction.
  • the acoustic device 100 performs active noise reduction in the full frequency band based on the pre-designed noise reduction parameters.
  • the pre-designed noise reduction parameters are usually not applicable to the active noise reduction of noise in a variety of external environments.
  • the noise reduction effect of the acoustic device may be poor, or the speaker 102 may have broken sound.
  • the noise reduction circuit 105 can provide multiple noise reduction modes.
  • the noise reduction circuit 105 can adaptively select a target noise reduction mode from multiple noise reduction modes based on the noise conditions of the external environment, and execute the target noise reduction mode.
  • adaptively selecting the target noise reduction mode means that the noise reduction mode can be switched autonomously, flexibly, intelligently, and/or adaptively according to the noise conditions of the external environment. It should be understood that the above-mentioned process of switching the noise reduction mode is automatically performed by the noise reduction circuit 105 without the manual participation of the user.
  • the above-mentioned multiple noise reduction modes may include: at least one of: a passive noise reduction mode, an anti-breaking noise reduction mode, a narrowband noise reduction mode or a normal noise reduction mode.
  • the active noise reduction function of the acoustic device 100 is turned off.
  • the active noise reduction function of the acoustic device 100 is turned on, and the noise reduction circuit 105 uses pre-designed noise reduction parameters to perform active noise reduction in the full frequency band based on at least one of the first sound signal or the second sound signal.
  • the active noise reduction function of the acoustic device 100 is turned on.
  • the active noise reduction process includes: the noise reduction circuit 105 determines the target frequency band based on the first sound signal, and the energy concentration in the target frequency band exceeds the preset threshold. Among them, the energy concentration in the target frequency band refers to the concentration degree of noise signal energy in the target frequency band. In some embodiments, the bandwidth corresponding to the target frequency band is less than the preset bandwidth, so the target frequency band can be called a narrowband. Further, the noise reduction circuit 105 can perform active noise reduction in the target frequency band (narrowband) based on at least one of the first sound signal or the second sound signal.
  • the noise reduction circuit 105 may adjust the noise reduction parameters of the noise reduction circuit 105 based on the target frequency band.
  • the adjusted noise reduction parameters may specify that the target frequency band is mainly subjected to active noise reduction (for example, the noise reduction depth of the target frequency band is greater than the noise reduction depth of other frequency bands), or the adjusted noise reduction parameters may specify that only the target frequency band is subjected to active noise reduction while other frequency bands are not subjected to active noise reduction.
  • the above-mentioned “adjusting the noise reduction parameters of the noise reduction circuit 105” may include: converting the full-band filter in the noise reduction circuit 105 into a narrow-band filter. By adjusting the noise reduction parameters based on the target frequency band, the above-mentioned embodiments may increase the noise reduction depth within the target frequency band and improve the noise reduction effect within the target frequency band.
  • the active noise reduction function of the acoustic device 100 is turned on.
  • the active noise reduction process includes: the noise reduction circuit 105 generates a noise reduction signal based on at least one of the first sound signal or the second sound signal, and makes the amplitude of the noise reduction signal within the amplitude range supported by the speaker 102. Further, the noise reduction circuit 105 sends a noise reduction signal to the speaker 102, so that the speaker 102 converts the noise reduction signal into a noise reduction frequency to reduce the volume of the ambient noise at the eardrum 202.
  • the above-mentioned amplitude range refers to the signal amplitude range supported by the speaker 102 when it can sound normally without breaking sound.
  • the breaking sound refers to the phenomenon that the vibration of the speaker diaphragm exceeds its linear range, resulting in serious sound distortion.
  • the speaker 102 When the amplitude of the signal input to the speaker 102 exceeds the above-mentioned amplitude range, the speaker 102 will cause the sound to break. When the amplitude of the signal input to the speaker 102 is within the amplitude range, the speaker 102 will not cause the sound to break.
  • the noise reduction circuit 105 ensures that the amplitude of the noise reduction signal is within the amplitude range supported by the speaker 102 , thus preventing the speaker 102 from sound distortion.
  • the noise reduction circuit 105 may generate a noise reduction signal in the following manner so that the amplitude of the noise reduction signal is within the amplitude range supported by the speaker 102: the noise reduction circuit 105 filters at least one of the first sound signal or the second sound signal to obtain a candidate noise reduction signal.
  • the noise reduction circuit 105 corrects the amplitude of the candidate noise reduction signal based on the amplitude range so that the corrected amplitude is within the amplitude range, and uses the corrected signal as the noise reduction signal.
  • the output end of the noise reduction circuit 105 may be provided with a dynamic range control (DRC).
  • DRC dynamic range control
  • the dynamic range controller is configured to adjust the amplitude of the input signal so that the amplitude of the output signal is within the amplitude range.
  • the candidate noise reduction signal is input into the dynamic range controller, and the amplitude of the candidate noise reduction signal is corrected by the dynamic range controller to obtain the noise reduction signal.
  • the noise reduction circuit 105 does not need to adjust the original noise reduction parameters, but only needs to add a post-amplitude correction link (for example, adding a dynamic range controller) to avoid distortion of the speaker 102 .
  • the noise reduction circuit 105 may generate a noise reduction signal in the following manner so that the amplitude of the noise reduction signal is within the amplitude range supported by the speaker 102: the noise reduction circuit 105 adjusts the filter gain corresponding to the noise reduction circuit 105 based on the first sound signal so that the amplitude of the output signal obtained after filtering is within the amplitude range. Further, the noise reduction circuit 105 filters at least one of the first sound signal or the second sound signal based on the adjusted noise reduction parameter to obtain the noise reduction signal.
  • the noise reduction circuit 105 only needs to adjust the filter gain to make the amplitude of the noise reduction signal fall within the amplitude range, without changing the circuit structure of the noise reduction circuit 105 .
  • the first filter gain corresponding to the first preset frequency band is less than the second filter gain corresponding to the second preset frequency band.
  • the frequency in the first preset frequency band is lower than the frequency in the second preset frequency band.
  • the frequency in the first preset frequency band is lower than the preset frequency, wherein the preset frequency may be 500Hz, 200Hz, 150Hz or other frequency values.
  • the first preset frequency band may be a low frequency band (e.g., a frequency band with a frequency less than 150Hz). Since the first preset frequency band corresponds to a smaller filter gain, the amplitude of the filtered noise cancellation signal corresponding to the first preset frequency band can be smaller, thereby avoiding distortion of the speaker 102 in the first preset frequency band.
  • the noise reduction circuit 105 when adjusting the filter gain, can reduce the first filter gain corresponding to the first preset frequency band on the basis of the default filter gain, while keeping the second filter gain corresponding to the second preset frequency band unchanged. In this way, the speaker 102 can be prevented from breaking without reducing the noise reduction effect corresponding to the second preset frequency band.
  • the present application provides an active noise reduction method P400, which can adaptively switch the noise reduction mode suitable for the current environment based on the noise conditions of the current environment, so that the acoustic device 100 can have a good noise reduction effect in different environments.
  • the active noise reduction method P400 can be independently applied to the acoustic device 100 provided by the present application, and can also be combined with other active noise reduction methods described in other parts of this article.
  • FIG16 shows a flowchart of another active noise reduction method P400 provided according to an embodiment of the present specification.
  • the active noise reduction method P400 may be executed by the noise reduction circuit 105 in the acoustic device 100.
  • the processor 107 in the noise reduction circuit 105 may read an instruction set stored in its local storage medium, and then execute the active noise reduction method P400 described in the present specification according to the instruction set.
  • the active noise reduction method P400 may include:
  • S42 Based on the first sound signal, adaptively select a target noise reduction mode from a plurality of noise reduction modes of the acoustic device.
  • the noise reduction circuit 105 can adaptively select a target noise reduction mode from multiple noise reduction modes based on at least one of the intensity or bandwidth type of the first sound signal.
  • the bandwidth type of the first sound signal can be divided into the following two types: narrowband type and non-narrowband type.
  • the narrowband type means that the bandwidth occupied by the first sound signal is less than the preset bandwidth. Compared with the non-narrowband type, the signal energy of the narrowband type is concentrated in a narrower frequency band.
  • the process of the noise reduction circuit 105 adaptively selecting the target noise reduction mode may include at least one of the following S42 - 1 , S42 - 2 , and S42 - 3 .
  • S42-1 Determine that the intensity of the first sound signal is less than or equal to a second intensity threshold, and select a passive noise reduction mode from the multiple noise reduction modes.
  • the second intensity threshold may correspond to the upper limit of the noise intensity in a relatively quiet environment.
  • the second intensity threshold may be 40 dB. That is, when the noise intensity in the external environment is relatively small (e.g., less than 40 dB), the noise reduction circuit 105 selects the passive noise reduction mode and turns off the active noise reduction function. This can reduce the power consumption of the acoustic device 100.
  • S42-2 Determine whether the intensity of the first sound signal is greater than or equal to a first intensity threshold, and select an anti-breaking noise reduction mode from among the multiple noise reduction modes.
  • the first intensity threshold is greater than the second intensity threshold.
  • the first intensity threshold may be 90 dB.
  • the noise reduction circuit 105 may select an anti-breaking noise reduction mode. This may prevent the speaker 102 from breaking.
  • S42-3 Determine that the intensity of the first sound signal is greater than a second intensity threshold, and the bandwidth type of the first sound signal is a narrowband type, and select a narrowband noise reduction mode from the multiple noise reduction modes.
  • the intensity of the first sound signal is greater than the second intensity threshold is a condition for turning on the active noise reduction function.
  • the noise reduction circuit 105 selects the narrowband noise reduction mode. In this way, active noise reduction can be performed only on the target frequency band where the energy of the first sound signal is concentrated, without having to perform active noise reduction in the full frequency band, which helps to increase the noise reduction depth in the target frequency band and improve the active noise reduction effect.
  • the judgment logic of the noise reduction circuit 105 for adaptively selecting the target noise reduction mode may be as follows: the noise reduction circuit 105 first determines whether the intensity of the first sound signal is less than the second intensity threshold. If so, the passive noise reduction mode is selected. If not, the active noise reduction function is turned on. Afterwards, the noise reduction circuit 105 determines whether the following two conditions are met, condition 1: the intensity of the first sound signal is greater than or equal to the first intensity threshold, condition 2: the bandwidth type of the first sound signal is a narrowband type.
  • the judgment result includes the following four situations: if only condition 1 is met, the anti-breaking noise reduction mode is selected; if only condition 2 is met, the narrowband noise reduction mode is selected; if both condition 1 and condition 2 are met, the anti-breaking noise reduction mode and the narrowband noise reduction mode can be selected at the same time. If both condition 1 and condition 2 are not met, the normal noise reduction mode is selected.
  • the noise reduction circuit 105 may first reduce the leakage signal component in the first sound signal to generate a quasi-ambient noise signal, and then, based on the quasi-ambient noise signal, adaptively select a target noise reduction mode from multiple noise reduction modes.
  • the above-mentioned method of reducing the leakage signal component in the first sound signal has been introduced above and will not be repeated here.
  • the noise reduction circuit 105 reduces the leakage signal component in the first sound signal so that the obtained quasi-ambient noise signal is closer to the actual ambient noise. Therefore, the target noise reduction mode is adaptively selected based on the quasi-ambient noise signal, so that the selected target noise reduction mode is more in line with the current environment, thereby improving the noise reduction effect.
  • the acoustic device 100 operates in a feedforward noise reduction mode, and the noise reduction circuit 105 performs a target noise reduction mode based on the first sound signal. In some embodiments, the acoustic device 100 operates in a feedback noise reduction mode, and the noise reduction circuit 105 performs a target noise reduction mode based on the second sound signal. In some embodiments, the acoustic device 100 operates in a hybrid noise reduction mode, and the noise reduction circuit 105 performs a target noise reduction mode based on the first sound signal and the second sound signal.
  • the active noise reduction method P400 can adaptively adjust the noise reduction mode based on the noise conditions of the external environment in which the acoustic device 100 is located, so that the active noise reduction process of the acoustic device 100 is more in line with the noise conditions of the current environment, which helps to improve the overall performance of the acoustic device 100.
  • the acoustic device 100 when the noise in the current environment is low, the acoustic device 100 can turn off the active noise reduction function to reduce power consumption; when the noise in the current environment is high, the acoustic device 100 can select the anti-breaking noise reduction mode to avoid the speaker 102 breaking; when the noise in the current environment is of narrowband type, the acoustic device 100 can select the narrowband noise reduction mode to increase the noise reduction depth and improve the noise reduction effect.
  • the present application also provides another active noise reduction method, which can be performed by the noise reduction circuit 105.
  • the noise reduction circuit 105 can obtain the user's instructions, and select the target noise reduction mode from multiple noise reduction modes according to the user's instructions, and then execute the target noise reduction mode.
  • the acoustic device 100 may be provided with an interactive control, and the user can switch different noise reduction modes through the interactive control.
  • the acoustic device 100 may provide an interactive interface, which may be presented on the screen of the acoustic device 100, or on a target device connected to the acoustic device 100 for communication, and the user may select different noise reduction modes through the interactive interface.
  • the user's instructions may indicate a specific noise reduction mode, so that the noise reduction circuit 105 may determine the noise reduction mode indicated by the instructions as the target noise reduction mode.
  • the user's instructions may specifically indicate the ambient noise situation in which the user is located, and the noise reduction circuit 105 may select the target noise reduction mode from multiple noise reduction modes based on the ambient noise situation indicated by the instructions. In this way, users can independently select a suitable active noise reduction mode according to their preferences and/or the current ambient noise conditions, thereby meeting the personalized needs of different users.
  • the present specification provides a non-transitory storage medium storing at least one set of executable instructions for active noise reduction.
  • the executable instructions When the executable instructions are executed by the processor, the executable instructions instruct the processor to implement the steps of the active noise reduction method described in the present specification.
  • various aspects of the present specification can also be implemented in the form of a program product, which includes a program code.
  • the program product When the program product is run on the acoustic device 100, the program code is used to enable the acoustic device 100 to perform the steps of the active noise reduction method described in the present specification.
  • the program product for implementing the above method can use a portable compact disk read-only memory (CD-ROM) to include program code and can be run on the acoustic device 100.
  • CD-ROM portable compact disk read-only memory
  • the program product of the present specification is not limited to this.
  • the readable storage medium can be any tangible medium containing or storing a program, which can be used by the instruction execution system or used in combination with it.
  • the program product can use any combination of one or more readable media.
  • the readable medium can be a readable signal medium or a readable storage medium.
  • the readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above.
  • readable storage media include: an electrical connection with one or more conductors, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.
  • the computer-readable storage medium may include a data signal propagated in a baseband or as part of a carrier wave, wherein the readable program code is carried. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above.
  • the readable storage medium may also be any readable medium other than a readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, device, or device.
  • the program code contained on the readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination of the above.
  • Program code for performing the operations of the present specification may be written in any combination of one or more programming languages, including object-oriented programming languages such as Java, C++, etc., and conventional procedural programming languages such as "C" or similar programming languages.
  • the program code may be executed entirely on the acoustic device 100, partially on the acoustic device 100, as a stand-alone software package, partially on the acoustic device 100 and partially on a remote computing device, or entirely on a remote computing device.

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Abstract

本申请提供一种开放式可穿戴声学设备及主动降噪方法，该声学设备包括第二声音传感器模组、扬声器和降噪电路。扬声器到第二声音传感器模组的传递函数与扬声器到耳膜的传递函数之间满足第一预设关系，且第一预设关系独立于声学设备的位姿。降噪电路基于第二声音信号和第一预设关系对降噪参数进行调整，并基于调整后的降噪参数进行主动降噪。本申请方案通过基于第二声音信号和第一预设关系对降噪参数进行调整，使得降噪参数符合准确的降噪目标，从而能够提升主动降噪的降噪效果。

Description

开放式可穿戴声学设备及主动降噪方法 技术领域
本说明书涉及音频技术领域，尤其涉及一种开放式可穿戴声学设备及主动降噪方法。
背景技术
现如今，具备声学输出功能的可穿戴设备(例如耳机)被越来越多的用户使用。特别地，一种声学设备不与人体形成封闭空间的听音方式(即，敞开耳朵的听音方式，例如，不需要将声学设备塞入耳道或罩住耳朵，或者，声学设备的表面设置有透音孔，使得耳膜与声学设备之间形成开放空间)，因其具有舒适、安全等特点被越来越多的应用于可穿戴声学设备中。这类可穿戴声学设备被称为开放式可穿戴设备。
上述开放式可穿戴声学设备在被佩戴在用户头部时，因不会与用户的耳膜之间形成封闭空间，所以，相较于封闭式声学设备(例如入耳耳机等)，耳朵外部的噪声源发出的声音会更多地进入耳内，这使得用户在佩戴开放式声学设备的时候能够听到更多的环境噪声，降低用户的听觉体验。因此，需要提供一种基于开放式可穿戴声学设备的主动降噪设计。
发明内容
本说明书提供一种开放式可穿戴声学设备及主动降噪方法，能够提升主动降噪效果。
第一方面，本说明书提供一种开放式可穿戴声学设备，包括：支撑件、扬声器、第二声音传感器模组和降噪电路；其中，扬声器与所述支撑件物理连接，在所述声学设备被佩戴于用户头部时所述扬声器与所述用户的耳膜之间形成开放空间；第二声音传感器模组与所述支撑件物理连接，被配置为采集第二声音并生成第二声音信号，其中，所述扬声器到所述第二声音传感器模组的传递函数与所述扬声器到所述耳膜的传递函数之间满足第一预设关系，且所述第一预设关系独立于所述声学设备的位姿；降噪电路被配置为：从所述第二声音传感器模组获取所述第二声音信号，基于所述第二声音信号和所 述第一预设关系，对所述降噪电路的降噪参数进行调整，基于所述调整后的降噪参数进行主动降噪。
在一些实施例中，所述声学设备还包括第一声音传感器模组，与所述支撑件物理连接，被配置为采集第一声音并生成第一声音信号，其中，所述第一声音信号包括来自环境噪声的环境噪声信号；以及为了基于所述调整后的降噪参数进行主动降噪，所述降噪电路：从所述第一声音传感器模组获取所述第一声音信号，对所述第一声音信号或所述第二声音信号中的至少一个进行滤波以生成消噪信号，以及向所述扬声器发送所述消噪信号，以使所述扬声器将所述消噪信号转换为消噪音频以降低所述耳膜处的环境噪声的音量。
在一些实施例中，所述第一声音传感器模组相对于所述扬声器远离所述耳膜，所述环境噪声到达所述第一声音传感器模组的相位超前于所述环境噪声到达所述扬声器的出音端的相位；以及所述第二声音传感器模组相对于所述扬声器贴近所述耳膜，所述环境噪声到达所述第二声音传感器模组的相位落后于所述环境噪声到达所述扬声器的出音端的相位。
在一些实施例中，为了对所述降噪电路的降噪参数进行调整，所述降噪电路：对所述扬声器到所述第二声音传感器模组的传递函数进行测量得到第一传递函数；基于所述第一传递函数、所述第一预设关系以及所述第二声音信号，确定所述耳膜处的环境噪声；以及以最小化所述耳膜处的环境噪声为目标，对所述降噪电路的降噪参数进行调整。
在一些实施例中，为了测量得到第一传递函数，所述降噪电路：向所述扬声器发送测试音频信号，以使所述扬声器发出对应的测试音频，所述测试音频被所述第二声音传感器模组采集到；获取所述第二声音传感器模组采集到的采集音频信号；以及根据所述测试音频信号和所述采集音频信号，确定所述第一传递函数。
在一些实施例中，所述环境噪声到所述第二声音传感器模组的传递函数与所述环境噪声到所述耳膜的传递函数之间满足第二预设关系，且所述第二预设关系独立于所述声学设备的位姿；以及为了对所述降噪电路的降噪参数进行调整，所述降噪电路：基于所述第二声音信号、所述第一预设关系和所述第二预设关系，对所述降噪电路的降噪参数进行调整。
在一些实施例中，为了对所述降噪电路的降噪参数进行调整，所述降噪电路：对所述扬声器到所述第二声音传感器模组的传递函数进行测量得到第一传递函数；基于所述第一传递函数、所述第一预设关系、所述第二预设关系以及所述第二声音信号，确定所 述耳膜处的环境噪声；以及以最小化所述耳膜处的环境噪声为目标，对所述降噪电路的降噪参数进行调整。
在一些实施例中，为了对所述降噪电路的降噪参数进行调整，所述降噪电路：获取所述用户在所述声学设备的多个工作模式中指示的目标工作模式，其中，在每个工作模式下所述降噪电路对应有默认降噪参数，且不同的工作模式对应的所述默认降噪参数不同；以及基于所述第二声音信号和所述第一预设关系，对所述目标工作模式对应的所述默认降噪参数进行调整。
在一些实施例中，所述降噪电路包括前馈滤波器或反馈滤波器中的至少一种，其中，前馈滤波器连接所述第一声音传感器模组和所述扬声器，并被配置为对所述第一声音信号进行滤波，反馈滤波器连接所述第二声音传感器模组和所述扬声器，并被配置为对所述第二声音信号进行滤波；以及所述降噪参数包括所述前馈滤波器的滤波参数或所述反馈滤波器的滤波参数中的至少一种。
在一些实施例中，所述滤波参数包括滤波增益、滤波相位或品质因子中的至少一种。
在一些实施例中，所述降噪电路包括前馈滤波器，连接所述第一声音传感器模组和所述扬声器，并被配置为对所述第一声音信号进行滤波，所述降噪参数包括所述前馈滤波器的滤波增益；以及为了对所述降噪参数进行调整，所述降噪电路：以最小化所述第二声音信号为降噪目标，确定所述前馈滤波器所需的第一滤波增益；根据所述第一滤波增益和所述第一预设关系，确定在以最小化所述耳膜处的所述环境噪声为降噪目标时，所述前馈滤波器所需的第二滤波增益；以及将所述前馈滤波器的当前滤波增益调整为所述第二滤波增益。
在一些实施例中，所述第一声音信号还包括来自所述扬声器的泄漏信号，其中，为了对所述第一声音信号进行滤波，所述降噪电路：通过削减所述第一声音信号中所述泄漏信号的成分生成准环境噪声信号，以及基于所述调整后的降噪参数，对所述准环境噪声信号进行滤波。
在一些实施例中，所述降噪电路包括：至少一个存储介质以及至少一个处理器，其中，所述存储介质存储有至少一个指令集，用于进行降噪；所述处理器同所述扬声器、第二声音传感模组以及所述至少一个存储介质通信连接，其中，当所述声学设备运行时，所述至少一个处理器读取所述至少一个指令集，并且根据所述至少一个指令集的指示执行：从所述第二声音传感器模组获取所述第二声音信号，基于所述第二声音信号和所述 第一预设关系，对所述降噪电路的降噪参数进行调整，基于所述调整后的降噪参数进行主动降噪。
在一些实施例中，所述声学设备为耳机、消声器、助听器、声学眼镜中的一种。
第二方面，本说明书还提供一种主动降噪方法，应用于如第一方面所述的开放式可穿戴声学设备，所述方法包括通过所述降噪电路：从所述第二声音传感器模组获取所述第二声音信号，基于所述第二声音信号和所述第一预设关系，对所述降噪电路的降噪参数进行调整，基于所述调整后的降噪参数进行主动降噪。
在一些实施例中，所述声学设备还包括第一声音传感器模组，与所述支撑件物理连接，被配置为采集第一声音并生成第一声音信号，其中，所述第一声音信号包括来自环境噪声的环境噪声信号；以及基于所述调整后的降噪参数进行主动降噪，包括：从所述第一声音传感器模组获取所述第一声音信号，对所述第一声音信号或所述第二声音信号中的至少一个进行滤波以生成消噪信号，以及向所述扬声器发送所述消噪信号，以使所述扬声器将所述消噪信号转换为消噪音频以降低所述耳膜处的环境噪声的音量。
在一些实施例中，所述第一声音传感器模组测得的所述环境噪声的相位超前于所述环境噪声到达所述扬声器的出音端的相位；以及所述第二声音传感器模组测得的所述环境噪声的相位落后于所述环境噪声到达所述扬声器的出音端的相位。
在一些实施例中，所述基于所述第二声音信号和所述第一预设关系，对所述降噪电路的降噪参数进行调整，包括：对所述扬声器到所述第二声音传感器模组的传递函数进行测量得到第一传递函数；基于所述第一传递函数、所述第一预设关系以及所述第二声音信号，确定所述耳膜处的环境噪声；以及以最小化所述耳膜处的环境噪声为目标，对所述降噪电路的降噪参数进行调整。
在一些实施例中，对所述扬声器到所述第二声音传感器模组的传递函数进行测量得到第一传递函数，包括：向所述扬声器发送测试音频信号，以使所述扬声器发出对应的测试音频，所述测试音频被所述第二声音传感器模组采集到；获取所述第二声音传感器模组采集到的采集音频信号；以及根据所述测试音频信号和所述采集音频信号，确定所述第一传递函数。
在一些实施例中，所述环境噪声到所述第二声音传感器模组的传递函数与所述环境噪声到所述耳膜的传递函数之间满足第二预设关系，且所述第二预设关系独立于所述声学设备的位姿；以及所述基于所述第二声音信号和所述第一预设关系，对所述降噪电路 的降噪参数进行调整，包括：基于所述第二声音信号、所述第一预设关系和所述第二预设关系，对所述降噪电路的降噪参数进行调整。
在一些实施例中，所述基于所述第二声音信号、所述第一预设关系和所述第二预设关系，对所述降噪电路的降噪参数进行调整，包括：对所述扬声器到所述第二声音传感器模组的传递函数进行测量得到第一传递函数；基于所述第一传递函数、所述第一预设关系、所述第二预设关系以及所述第二声音信号，确定所述耳膜处的环境噪声；以及以最小化所述耳膜处的环境噪声为目标，对所述降噪电路的降噪参数进行调整。
在一些实施例中，所述基于所述第二声音信号和所述第一预设关系，对所述降噪电路的降噪参数进行调整，包括：获取所述用户在所述声学设备的多个工作模式中指示的目标工作模式，其中，在每个工作模式下所述降噪电路对应有默认降噪参数，且不同的工作模式对应的所述默认降噪参数不同；以及基于所述第二声音信号和所述第一预设关系，对所述目标工作模式对应的所述默认降噪参数进行调整。
在一些实施例中，所述降噪电路包括前馈滤波器或反馈滤波器中的至少一种；其中，前馈滤波器连接所述第一声音传感器模组和所述扬声器，并被配置为对所述第一声音信号进行滤波，反馈滤波器连接所述第二声音传感器模组和所述扬声器，并被配置为对所述第二声音信号进行滤波；以及所述降噪参数包括所述前馈滤波器的滤波参数或所述反馈滤波器的滤波参数中的至少一种。
在一些实施例中，所述滤波参数包括滤波增益、滤波相位或品质因子中的至少一种。
在一些实施例中，所述降噪电路包括前馈滤波器，连接所述第一声音传感器模组和所述扬声器，并被配置为对所述第一声音信号进行滤波，所述降噪参数包括所述前馈滤波器的滤波增益；以及所述基于所述第二声音信号和所述第一预设关系，对所述降噪电路的降噪参数进行调整，包括：以最小化所述第二声音信号为降噪目标，确定所述前馈滤波器所需的第一滤波增益；根据所述第一滤波增益和所述第一预设关系，确定在以最小化所述耳膜处的所述环境噪声为降噪目标时，所述前馈滤波器所需的第二滤波增益；以及将所述前馈滤波器的当前滤波增益调整为所述第二滤波增益。
在一些实施例中，所述第一声音信号还包括来自所述扬声器的泄漏信号，以及所述基于所述调整后的降噪参数，对所述第一声音信号进行滤波，包括：通过削减所述第一声音信号中所述泄漏信号的成分生成准环境噪声信号，以及基于所述调整后的降噪参数，对所述准环境噪声信号进行滤波。
由以上技术方案可知，本说明书提供的开放式可穿戴声学设备及主动降噪方法，该 声学设备包括第二声音传感器模组、扬声器和降噪电路。其中，扬声器到第二声音传感器模组的传递函数与扬声器到耳膜的传递函数之间满足第一预设关系，且所述第一预设关系独立于声学设备的位姿。降噪电路可以从第二声音传感器模组获取第二声音信号，基于第二声音信号和所述第一预设关系，对降噪参数进行调整，并基于调整后的降噪参数进行主动降噪。由于降噪电路基于第二声音信号和所述第一预设关系对降噪参数进行调整，使得调整后的降噪参数符合准确的降噪目标，从而能够提升主动降噪的降噪效果。
本说明书提供的开放式可穿戴声学设备及主动降噪方法的其他功能将在以下说明中部分列出。本说明书提供的开放式可穿戴声学设备及主动降噪方法的创造性方面可以通过实践或使用下面详细示例中所述的方法、装置和组合得到充分解释。
附图说明
为了更清楚地说明本说明书实施例中的技术方案，下面将对实施例描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本说明书的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1A示出了根据本说明书的实施例提供的一种声学设备的佩戴场景示意图；
图1B示出了采用入耳佩戴方式的声学设备的示意图；
图1C示出了采用挂耳佩戴方式的声学设备的示意图；
图1D示出了采用夹耳佩戴方式的声学设备的示意图；
图2示出了根据本说明书的实施例提供的一种声学设备的硬件结构示意图；
图3示出了声学设备中不同位置处的声音传感器采集到的泄漏信号的示意图；
图4示出了根据本说明书的实施例提供的一种主动降噪方法的流程图；
图5示出了根据本说明书的实施例提供的一种声学设备的主动降噪原理示意图；
图6示出了根据本说明书的实施例提供的一种主动降噪方法的降噪效果的示意图；
图7示出了根据本说明书的实施例提供的另一种主动降噪方法的流程图；
图8A示出了在第一用户佩戴声学设备的情况下采用不同的前馈滤波增益对耳膜处的环境噪声进行前馈降噪的频响曲线的示意图；
图8B示出了在第一用户佩戴声学设备的情况下采用不同的前馈滤波增益对第二声 音信号进行前馈降噪的频响曲线的示意图；
图9A示出了在第二用户佩戴声学设备的情况下采用不同的前馈滤波增益对耳膜处的环境噪声进行前馈降噪的频响曲线的示意图；
图9B示出了在第二用户佩戴声学设备的情况下采用不同的前馈滤波增益对第二声音信号进行前馈降噪的频响曲线的示意图；
图10示出了第一声音传感器模组中包括2个声音传感器的情况下各声音传感器的分布示意图；
图11示出了第一声音传感器模组中包括3个声音传感器的情况下各声音传感器的分布示意图；
图12示出了根据本说明书的实施例提供的又一种主动降噪方法的流程图；
图13示出了根据本说明书的实施例提供的另一种声学设备的主动降噪原理示意图；
图14示出了根据本说明书的实施例提供的一组频响曲线的示意图；
图15示出了根据本说明书的实施例提供的又一组频响曲线的示意图；以及
图16示出了根据本说明书的实施例提供的又一种主动降噪方法的流程图。
具体实施方式
以下描述提供了本说明书的特定应用场景和要求，目的是使本领域技术人员能够制造和使用本说明书中的内容。对于本领域技术人员来说，对所公开的实施例的各种局部修改是显而易见的，并且在不脱离本说明书的精神和范围的情况下，可以将这里定义的一般原理应用于其他实施例和应用。因此，本说明书不限于所示的实施例，而是与权利要求一致的最宽范围。
这里使用的术语仅用于描述特定示例实施例的目的，而不是限制性的。比如，除非上下文另有明确说明，这里所使用的，单数形式“一”，“一个”和“该”也可以包括复数形式。当在本说明书中使用时，术语“包括”、“包含”和/或“含有”意思是指所关联的整数，步骤、操作、元素和/或组件存在，但不排除一个或多个其他特征、整数、步骤、操作、元素、组件和/或组的存在或在该系统/方法中可以添加其他特征、整数、步骤、操作、元素、组件和/或组。
考虑到以下描述，本说明书的这些特征和其他特征、以及结构的相关元件的操作和 功能、以及部件的组合和制造的经济性可以得到明显提高。参考附图，所有这些形成本说明书的一部分。然而，应该清楚地理解，附图仅用于说明和描述的目的，并不旨在限制本说明书的范围。还应理解，附图未按比例绘制。
本说明书中使用的流程图示出了根据本说明书中的一些实施例的系统实现的操作。应该清楚地理解，流程图的操作可以不按顺序实现。相反，操作可以以反转顺序或同时实现。此外，可以向流程图添加一个或多个其他操作。可以从流程图中移除一个或多个操作。
为了方便描述，首先对本说明书中出现的术语进行解释：
封闭式声学设备：一些声学设备在被佩戴的状态下，声学设备与用户的耳膜之间形成封闭空间，该类声学设备可以被称为封闭式声学设备。例如，声学设备可以采用入耳式设计(如耳塞式耳机)、封闭式耳罩设计或其他类似的设计，使其与用户的耳膜之间形成封闭空间。在用户佩戴封闭式声学设备时，上述封闭空间能够从物理上隔绝外部噪声，降低外界噪声对用户的干扰。但是，用户在长时间佩戴封闭式声学设备时，通常会感觉不舒适。
开放式声学设备：一些声学设备在被佩戴的状态下，声学设备与用户的耳膜之间形成开放空间，该类声学设备可以被称为开放式声学设备。例如，声学设备可以不塞入耳道或不罩住耳道，或者声学设备的表面设置有透音孔，使其与耳膜之间形成开放空间。开放式声学设备能够提高用户的佩戴舒适度，并使用户听到的声音更加通透自然。
噪声：在本申请中任何不受用户欢迎、用户不想要、或者干扰用户听觉的声音，都可以称为噪声。
被动降噪：可以是指采用被动的方式进行降噪的技术。上述被动的方式包括但不限于：消除(或部分消除)噪声源、阻止噪声的传播、或阻止用户的耳朵听到噪声等，或其任何组合。比如，通过在耳内形成封闭空间以实现降噪的技术属于被动降噪技术。被动降噪技术也可以称为无源降噪技术。被动降噪并不是消除噪声，而是通过物理的方式来抑制噪声。
主动降噪：可以是指通过生成消噪信号(例如，与要抑制的噪声相位相反的信号)以主动的方式进行降噪的技术。具体的，采用主动降噪技术的声学设备可以通过声音传感器采集噪声信号，通过降噪电路生成一个用于抵消噪声信号的消噪信号，并通过扬声器播放该消噪信号，使得消噪信号与噪声信号相抵，从而消除噪声。主动降噪技术也可以 称为有源降噪技术。主动降噪技术可以分为前馈降噪、反馈降噪和混合降噪。
前馈降噪：在声学设备的外侧放置声音传感器，通过声音传感器采集环境噪声并生成环境噪声信号，通过前馈滤波器对环境噪声信号进行滤波生成消噪信号，并通过扬声器播放该消噪信号。这样，消噪信号与耳膜处的环境噪声抵消(或部分抵消)，从而降低用户听到的环境噪声的音量。上述前馈滤波器主要用来补偿耳膜处的环境噪声与声音传感器采集到的环境噪声之间的差异。在前馈降噪系统中，扬声器和声音传感器之间形成开环的降噪控制系统。
反馈降噪：在声学设备的内侧放置声音传感器，通过声音传感器采集耳膜附近区域的环境噪声，通过反馈滤波器对环境噪声进行滤波生成消噪信号，并通过扬声器播放该消噪信号。这样，消噪信号与耳膜处的环境噪声抵消(或部分抵消)，从而降低用户听到的环境噪声的音量。在反馈降噪系统中，扬声器和声音传感器之间形成闭环的降噪控制系统。
混合降噪：混合降噪是指综合采用前馈降噪和反馈降噪的技术。通常而言，相较于单独的前馈降噪或单独的反馈降噪而言，混合降噪能够进一步提升降噪效果。
本申请提供一种开放式可穿戴声学设备(后文简称为“声学设备”)及其主动降噪方法，在用户佩戴声学设备的场景中，能够降低用户听到的环境噪声的音量，减少环境噪声对用户的干扰。
图1A示出了根据本说明书的实施例提供的一种声学设备的佩戴场景示意图。在场景001下，声学设备100被佩戴于用户的耳朵200部位。其中，耳朵200可以包括耳廓201和耳膜202。声学设备100可以被佩戴于耳廓201处，并且声学设备100与耳膜202之间不封闭，形成开放空间。在场景001下还可以包括噪声源300，噪声源300的数量可以为一个或多个。噪声源300被配置为发出环境噪声(例如，不受用户欢迎、用户不想要、或者干扰用户听觉的声音)。声学设备100被配置为抑制或消除人耳听到的环境噪声。具体而言，声学设备100采用主动降噪的方式，通过生成并输出消噪信号(与环境噪声相位相反的信号)来抑制或消除环境噪声。
在一些实施例中，声学设备100可以为耳机、消声器、助听器、声学眼镜等，或其任意组合。为了便于理解，图1A中以声学设备100为耳机为例进行示意。当声学设备100为声学眼镜时，声学眼镜的镜腿靠近耳朵的区域可以设置有声音输出装置，被配置为向用户的耳朵输出声音。需要说明的是，声学设备100可以以任意方式被佩戴于用户 的耳朵200部位，本申请对此不作限定。例如声学设备100的佩戴方式可以包括头戴式、入耳佩戴方式、绕颈佩戴方式、挂耳佩戴方式、或夹耳佩戴方式等，或其任意组合。
在一些实施例中，场景001中还可以包括：网络和目标设备(图1A中未示出)。其中，目标设备可以为具有音频输出功能的电子设备。声学设备100和目标设备可以通过网络通信连接，二者之间可以通过网络相互传输数据或信号。例如，目标设备可以将待播放的目标音频(例如音乐、语音等)通过网络发送给声学设备100，以供声学设备100向用户输出上述目标音频。
在一些实施例中，目标设备可以设置有音频采集装置，通过音频采集装置采集得到目标音频。在一些实施例中，目标设备可以从其他设备接收上述目标音频。在一些实施例中，上述目标设备可以包括移动设备、平板电脑、笔记本电脑、机动车辆的内置设备或类似内容，或其任意组合。在一些实施例中，所述移动设备可包括智能家居设备、智能移动设备、虚拟现实设备、增强现实设备或类似设备，或其任意组合。在一些实施例中，所述智能家居装置可包括智能电视、台式电脑、智能音箱等，或任意组合。在一些实施例中，所述智能移动设备可包括智能手机、个人数字辅助、游戏设备、导航设备等，或其任意组合。在一些实施例中，所述虚拟现实设备或增强现实设备可能包括虚拟现实头盔、虚拟现实眼镜、虚拟现实补丁、增强现实头盔、增强现实眼镜、增强现实补丁或类似内容，或其中的任何组合。例如，所述虚拟现实设备或所述增强现实设备可能包括谷歌眼镜、头戴式显示器、VR等。在一些实施例中，所述机动车中的内置装置可包括车载计算机、车载电视等。
在一些实施例中，网络可以是任何类型的无线网络。比如，网络可以包括电信通信网络、内联网、互联网、局域网(LAN)、广域网(WAN)、无线局域网(WLAN)、大都市市区网(MAN)、广域网(WAN)、公用电话交换网(PSTN)、蓝牙网络、ZigBee网络、近场通信(NFC)网络或类似网络。在一些实施例中，上述网络可以为蓝牙网络，该情况下，声学设备100和目标设备之间可以基于蓝牙(bluetooth)协议进行通信。
继续参见图1A，声学设备100可以包括：支撑件101、扬声器102、降噪电路105和至少一个声音传感器模组。其中，扬声器102和所述至少一个声音传感器模组均可以与支撑件101物理连接。
支撑件101可用于辅助声学设备100固定于用户耳部。例如，支撑件101可以为声学设备100的壳体或者其他附加结构。需要说明的是，本申请对于支撑件101的具体形 态不作限定。应理解，支撑件101的具体形态与声学设备100支持的佩戴方式有关。
图1B示出了采用入耳佩戴方式的声学设备的示意图。该情况下，支撑件101可以采用贴合耳廓201的设计，支撑件101上存在一个或多个支撑点与耳廓201上的预设点贴合。图1C示出了采用挂耳佩戴方式的声学设备的示意图。该情况下，支撑件101可以采用悬挂结构，使得声学设备100可悬挂于耳廓201上。图1D示出了采用夹耳佩戴方式的声学设备的示意图。该情况下，支撑件101可以采用夹持结构，使得支撑件101可夹持在耳廓201上。
继续参见图1A，扬声器102可以设置在声学设备100靠近耳道口的一侧。在声学设备100被佩戴于用户头部时，扬声器102与用户的耳膜202之间形成有开放空间。在一些实施例中，在声学设备100被佩戴于用户头部时，扬声器102可以靠近用户的耳道口，且不堵塞耳道口，从而扬声器102与耳膜202之间形成有开放空间。在一些实施例中，声学设备100的壳体可以采用非封闭式壳体，例如，壳体上设置有透音孔，使得扬声器102与耳膜202之间形成开放空间。
扬声器102可以被配置为基于音频信号生成音频(或者说将音频信号转换为音频)。这里的音频信号是承载了声音信息的电信号，音频指经过扬声器播放出来的声音信号。当声音从最初的声源(比如环境噪声源、人的喉咙等)发出后，经过采集声音的传感器(比如麦克风)转换成承载了该声音信息的电信号，也就是所述音频信号。扬声器102也可以称为电声换能器，在工作时可以接受该承载了声音信息的音频信号，再将之转换成声音信号播放出来。在一些实施例中，声学设备100中可以包括多个扬声器102。该情况下，上述多个扬声器102可以采用阵列方式排布，例如，线性阵列、平面阵列、球形阵列或其他阵列等。
在一些实施例中，上述至少一个声音传感器模组可以包括第一声音传感器模组103。如图1A所示，第一声音传感器模组103相对于扬声器102远离耳膜202。也就是说，第一声音传感器103可以设置在声学设备100的外侧(在声学设备100被佩戴在用户头部时，声学设备100远离耳膜202的一侧作为外侧)。在一些实施例中，第一声音传感器模组103可以包括一个或多个声音传感器。当第一声音传感器模组103包括多个声音传感器时，该多个声音传感器可以为采用阵列方式排布，例如，线性阵列、平面阵列、球形阵列或其他阵列等。在一些实施例中，上述声音传感器为用于采集声音并将声音转换为电信号的装置，例如麦克风。
在一些实施例中，上述至少一个声音传感器模组可以包括第二声音传感器模组104。第二声音传感器模组104相对于扬声器102贴近(或者说靠近)耳膜202。也就是说，第二声音传感器模组104设置在声学设备100的内侧(在声学设备100被佩戴在用户头部时，声学设备100靠近耳膜202的一侧作为内侧)。在一些实施例中，第二声音传感器模组104可以包括一个或多个声音传感器。当第二声音传感器模组104包括多个声音传感器时，该多个声音传感器可以为采用阵列方式排布，例如，线性阵列、平面阵列、球形阵列或其他阵列等。
在一些实施例中，上述至少一个声音传感器模组可以同时包括第一声音传感器模组103和第二声音传感器模组104。
第一声音传感器模组103被配置为采集第一声音并生成对应于所述第一声音的第一声音信号。其中，第一声音可以为声音模拟信号，第一声音信号可以为电信号。应理解，由于声学设备100所处的环境中存在噪声源300，第一声音传感器模组103可以采集到噪声源300发出的环境噪声。另外，由于扬声器102与耳膜202之间形成开放空间，第一声音传感器模组103也可以采集到扬声器102发出的声音。为了便于描述，本申请中将第一声音传感器模组103采集到的来自扬声器102的声音称为泄漏声音。因此，第一声音传感器模组103采集到的第一声音包括环境噪声和泄漏声音。相应的，第一声音传感器模组103生成的第一声音信号包括：来自噪声源300的环境噪声信号和来自扬声器102的泄漏信号。
第一声音传感器模组103相对于扬声器102远离耳膜202，也就是说，第一声音传感器模组103相对于扬声器102距离噪声源300更近。因此，环境噪声到达第一声音传感器模组103的时刻早于环境噪声到达扬声器102的出音端的时刻。换言之，环境噪声到达第一声音传感器模组103的相位超前于环境噪声到达扬声器102的出音端的相位。因此，第一声音传感器模组103采集到的第一声音信号可用于前馈降噪。
第二声音传感器模组104被配置为采集第二声音并生成对应于所述第二声音的第二声音信号。其中，第二声音可以为声音模拟信号，第二声音信号可以为电信号。针对开放式声学设备而言，第二声音传感器模组104一方面可以采集到噪声源300发出的环境噪声，另一方面可以采集到扬声器102发出的声音。因此，第二声音传感器模组104采集到的第二声音包括环境噪声的成分和扬声器102所发声音的成分。在主动降噪场景中，噪声源300发出的环境噪声沿空气传导到达所述开放空间，所述开放空间内的一部分环 境噪声在主动降噪过程中被扬声器102的声音抵消或者减弱，因此，第二声音传感器模组104采集到的第二声音也可以称为残留噪声，即所述开放空间内还剩余的环境噪声。
第二声音传感器模组104相对于扬声器102贴近(靠近)耳膜202，也就是说，第二声音传感器模组104相对于扬声器102距离噪声源300更远。因此，环境噪声到达第二声音传感器模组104的时刻晚于环境噪声到达扬声器102的出音端的时刻。换言之，环境噪声到达第二声音传感器模组104的相位落后于环境噪声到达扬声器102的出音端的相位。因此，第二声音传感器模组104采集到的第二声音信号可用于反馈降噪。
继续参见图1A，降噪电路105与第一声音传感器模组103、第二声音传感器模组104和扬声器102连接，被配置为执行主动降噪，以降低人耳听到的环境噪声的音量。其中，上述的主动降噪可以为前馈降噪、反馈降噪、混合降噪中的任意一种。
在一些实施例中，降噪电路105可以被配置为执行前馈降噪。该情况下，降噪电路105可以从第一声音传感器模组103获取第一声音信号，并基于第一声音信号进行主动降噪。
在一些实施例中，降噪电路105基于第一声音信号进行主动降噪可以包括：降噪电路105基于第一声音信号生成第一消噪信号。降噪电路105向扬声器102发送第一消噪信号，以使扬声器102将所述第一消噪信号转换为第一消噪音频。所述第一消噪信号的相位可以被设置成与耳膜202处空间的环境噪声的相位相反或者近似相反或呈预设的相位差，以使所述第一消噪音频的相位与耳膜202处以及附近空间的环境噪声的相位相反或近似相反，从而降低了耳膜202处的环境噪声的音量。在一些实施例中，降噪电路105中可以包括前馈滤波器，连接第一声音传感器模组103和扬声器102。降噪电路105从第一声音传感器103获取第一声音信号之后，可以将第一声音信号输入前馈滤波器，通过前馈滤波器对第一声音信号进行滤波得到第一消噪信号，并将第一消噪信号输出至扬声器102。其中，前馈滤波器被配置为对第一声音信号的增益或相位中的至少一项进行调整，使得得到的第一消噪信号能够与耳膜202处的至少部分环境噪声相抵。
在一些实施例中，降噪电路105也可以被配置为执行反馈降噪。该情况下，降噪电路105可以从第二声音传感器模组104获取第二声音信号，并基于第二声音信号进行主动降噪。
在一些实施例中，降噪电路105基于第二声音信号进行主动降噪的过程可以包括：降噪电路105基于第二声音信号生成第二消噪信号。降噪电路105向扬声器102发送第 二消噪信号，以使扬声器102将所述第二消噪信号转换为第二消噪音频。第二消噪信号可以被设置为与耳膜202处的环境噪声的相位相反、近似相反、或者呈预设的相位差，以使所述第二消噪音频的相位与耳膜202处以及附近空间的环境噪声的相位相反或者近似相反，从而降低耳膜202处的环境噪声的音量。在一些实施例中，降噪电路105中可以包括反馈滤波器，连接第二声音传感器模组103和扬声器102。降噪电路105从第二声音传感器103获取第二声音信号之后，可以将第二声音信号输入反馈滤波器，通过反馈滤波器对第二声音信号进行滤波得到第二消噪信号，并将第二消噪信号输出至扬声器102。其中，反馈滤波器被配置为对第二声音信号的增益或相位中的至少一项进行调整，使得得到的第二消噪信号能够与耳膜202处的至少部分环境噪声相抵。
在一些实施例中，降噪电路105也可以被配置为执行混合降噪。该情况下，降噪电路105可以从第一声音传感器模组103获取第一声音信号，从第二声音传感器模组104获取第二声音信号，并基于第一声音信号和第二声音信号进行主动降噪。
在一些实施例中，降噪电路105基于第一声音信号和第二声音信号进行主动降噪的过程可以包括：降噪电路105基于第一声音信号生成第一消噪信号，并基于第二声音信号生成第二消噪信号。降噪电路105向扬声器102发送第一消噪信号和第二消噪信号，以使扬声器102将所述第一消噪信号和所述第二消噪信号转换为消噪音频以降低耳膜202处以及附近空间的环境噪声的音量。在一些实施例中，降噪电路105中可以包括前馈滤波器和反馈滤波器。其中，前馈滤波器连接第一声音传感器模组103和扬声器102。反馈滤波器连接第二声音传感器模组104和扬声器102。降噪电路105可以将第一声音信号输入前馈滤波器，通过前馈滤波器对第一声音信号进行滤波得到第一消噪信号，并将第二声音信号输入反馈滤波器，通过反馈滤波器对第二声音信号进行滤波得到第二消噪信号。进而降噪电路105向扬声器102发送第一消噪信号和第二消噪信号。其中，前馈滤波器被配置为对第一声音信号的增益或相位中的至少一项进行调整，使得得到的第一消噪信号经扬声器102转换后产生的音频能够与耳膜202处以及附近空间的至少部分环境噪声相抵(即，所述音频的相位同耳膜202处以及附近空间的至少部分环境噪声相位相反或者近似相反)。反馈滤波器被配置为对第二声音信号的增益或相位中的至少一项进行调整，使得得到的第一消噪信号经扬声器102转换后产生的音频能够与耳膜202处的至少部分环境噪声相抵(即，所述音频的相位同耳膜202处以及附近空间的至少部分环境噪声相位相反或者近似相反)。在一些实施例中，降噪电路105可以向扬声器102分别发送第一消噪信号和第二消噪信号。在一些实施例中，降噪电路105可以先对第一 消噪信号和第二消噪信号进行合成，得到合成消噪信号，然后向扬声器102发送所述合成消噪信号。
在一些实施例中，降噪电路105可以被配置为执行本说明书描述的主动降噪方法。此时，降噪电路105可以存储有执行本说明书描述的主动降噪方法的数据或指令，并可以执行或用于执行所述数据或指令。在一些实施例中，降噪电路105可以包括具有数据信息处理功能的硬件设备和驱动该硬件设备工作所需必要的程序。上述的主动降噪方法将在后面的内容中详细介绍。
图2示出了根据本说明书的实施例提供的一种声学设备的硬件结构示意图。如图2所示，在一些实施例中，降噪电路105可以包括：至少一个存储介质106和至少一个处理器107。所述至少一个处理器107同扬声器102、第一声音传感器模组103和第二声音传感器模组104通信连接。需要说明的是，仅仅是出于展示的需要，本申请中的降噪电路105包括了至少一个存储介质106和至少一个处理器107。本领域普通技术人员(one of ordinary skill in the art)可以理解的是，降噪电路105也可以包括其他硬件电路结构，在本申请中不做限制，只要能够满足本申请中提到的功能而不偏离本申请的精神便可。
在一些实施例中，声学设备100还可以包括通信端口108。通信端口108用于声学设备100同外界的数据通信，比如，通信端口108可以用于声学设备100同其他设备之间的数据通信。
在一些实施例中，声学设备100还可以包括内部通信总线109。内部通信总线109可以连接不同的系统组件。例如，扬声器102、第一声音传感器模组103、第二声音传感器模组104、处理器107、存储介质106和通信端口108均可以通过内部通信总线109连接。
存储介质106可以包括数据存储装置。所述数据存储装置可以是非暂时性存储介质，也可以是暂时性存储介质。比如，所述数据存储装置可以包括磁盘1061、只读存储介质(ROM)1062或随机存取存储介质(RAM)1063中的一种或多种。存储介质106还包括存储在所述数据存储装置中的至少一个指令集。指令集中包括指令，所述指令是计算机程序代码，所述计算机程序代码可以包括执行本说明书提供的主动降噪方法的程序、例程、对象、组件、数据结构、过程、模块等等。
至少一个处理器107用以执行上述至少一个指令集。当声学设备100运行时，至少一个处理器107读取所述至少一个指令集，并且根据所述至少一个指令集的指示，执行 本说明书提供的主动降噪方法。处理器107可以执行通信方法包含的所有步骤或部分步骤。处理器107可以是一个或多个处理器的形式，在一些实施例中，处理器107可以包括一个或多个硬件处理器，例如微控制器，微处理器，精简指令集计算机(RISC)，专用集成电路(ASIC)，特定于应用的指令集处理器(ASIP)，中心处理单元(CPU)，图形处理单元(GPU)，物理处理单元(PPU)，微控制器单元，数字信号处理器(DSP)，现场可编程门阵列(FPGA)，高级RISC机器(ARM)，可编程逻辑器件(PLD)，能够执行一个或多个功能的任何电路或处理器等，或其任何组合。仅仅为了说明问题，图2所示的声学设备100示例了仅包括一个处理器107的情况。然而，应当注意，本说明书中声学设备100还可以包括多个处理器，因此，本说明书中披露的操作和/或方法步骤可以如本说明书所述的由一个处理器执行，也可以由多个处理器联合执行。例如，如果在本说明书中声学设备100的处理器107执行步骤A和步骤B，则应该理解，步骤A和步骤B也可以由两个不同处理器120联合或分开执行(例如，第一处理器执行步骤A，第二处理器执行步骤B，或者第一和第二处理器共同执行步骤A和B)。
本领域普通技术人员可知，图2只是降噪电路105的一种设计方案。降噪电路105也可以被设计成其他硬件形式而不偏离本申请中所公开的发明的精神。降噪电路105的具体设计方案在本申请中不做限定。
如前所示，在开放式声学设备中，第一声音传感器模组103采集并生成的第一声音信号并不是单纯的环境噪声信号，而是包括环境噪声信号和泄漏信号的混合声音信号。因此，如果降噪电路105直接基于第一声音信号进行前馈降噪，泄漏信号会对前馈降噪过程产生影响，使得前馈降噪效果不佳。
在一些实施例中，为了降低泄漏信号对前馈降噪效果的影响，声学设备100可以采用物理隔离的方式，将第一声音传感器模组103设置在扬声器102的声学零点位置。例如，扬声器102可以采用偶极子喇叭的设计，第一声音传感器模组103位于偶极子喇叭的声学零点位置上。这样，第一声学传感器模组103无法采集到来自扬声器102的泄漏信号，或者仅采集到很少的泄漏信号。
图3示出了声学设备中不同位置处的声音传感器采集到的泄漏信号的示意图。其中，FF1和FF2表示位于扬声器102的声学零点位置的声音传感器，FF3表示位于扬声器102附近的声音传感器。在测试过程中，给扬声器102激励信号后，获取FF1采集到的泄漏信号得到如图3所示曲线301，获取FF2采集到的泄漏信号得到如图3所示的曲线302， 获取FF3采集到的泄漏信号得到如图3所示的曲线303。由图3可以看出，在环境频率较低(例如低于1500Hz)时，FF1和FF2采集到的泄漏信号相对于FF3采集到的泄漏信号降低20dB以上，能够实现一定的降噪效果。
在一些实施例中，第一声学传感器模组103与扬声器102的声学零点位置之间的距离可以在非零的预设范围之内。也就是说，可以将第一声音传感器模组103设置在距离扬声器102的声学零点位置较近的位置，而非严格位于扬声器102的声学零点位置。这样，能够降低对声学设备100的结构设计和组装工艺的要求。
本申请提供一种主动降噪方法P100，能够通过削减第一声音信号中的泄漏信号的成分，来降低泄漏信号对前馈降噪的影响，从而提高降噪效果。上述主动降噪方法P100可以应用于“第一声音传感器模组103未设置在扬声器102的声学零点位置”场景，也可以应用于“第一声音传感器模组103设置在扬声器102的声学零点位置”场景。在“第一声音传感器模组103设置在扬声器102的声学零点位置”场景中，由于在部分频段依然存在扬声器信号泄露至第一声音传感器模组的问题(例如图3中在频率高于5000Hz以上时，FF1和FF2采集到泄漏信号与FF3采集到的泄漏信号基本相当)，因此，可以针对上述存在泄露的特定频段，采用本申请提供的主动降噪方法P100进行主动降噪，以提升降噪效果。所述主动降噪方法P100可以独立的应用于本申请提供的声学设备100上，也可以与本文其他部分描述的其他主动降噪方法相互结合。
图4示出了根据本说明书的实施例提供的一种主动降噪方法的流程图。该主动降噪方法P100可以由声学设备100中的降噪电路105执行。例如，当降噪电路105采用了图2所示的结构时，降噪电路105中的处理器107可以读取存储在其本地存储介质中的指令集，然后根据指令集的指示，执行本说明书描述的主动降噪方法P100。如图4所示，主动降噪方法P100可以包括：
S11：从第一声音传感器模组获取第一声音信号，所述第一声音信号包括来自环境噪声的环境噪声信号和来自扬声器的泄漏信号。
如前所述，第一声音传感器模组103采集第一声音，并将第一声音转换为第一声音信号。第一声音实际为来自噪声源300的环境噪声和来自扬声器102的泄漏声音混合后的声音，因此，第一声音信号中同时包括上述环境噪声对应的环境噪声信号和上述泄漏声音对应的泄漏信号。降噪电路105与第一声音传感器模组103连接，可以从第一声音传感器模组103获取第一声音信号。
S12：通过削减所述第一声音信号中所述泄漏信号的成分，生成准环境噪声信号。
具体而言，降噪电路105可以通过某些方式测量得到第一声音信号中所含的泄漏信号的成分，进而，从第一声音信号中减去上述泄漏信号的成分，得到准环境噪声信号。需要说明的是，上述测量得到的泄漏信号的成分可能与实际的泄漏信号有所偏差，因此，从第一声音信号中减去上述测量得到的泄漏信号的成分，得到的结果不严格等于实际的环境噪声信号，而是近似等于实际的环境噪声信号。因此，在本申请中将削减的结果称为准环境噪声信号。所述准环境噪声信号可以理解为对第一声音信号进行泄漏补偿得到的补偿信号。
图5示出了根据本说明书的实施例提供的一种声学设备的主动降噪原理示意图。如图5所示，假设：
噪声源300发出的声音到第一声音传感器模组103测量得到的音频信号之间的传递函数记为h1；
噪声源300发出的声音到第二声音传感器模组104测量得到的音频信号之间的传递函数记为h2；
扬声器102发出的声音到第一声音传感器模组103测量得到的音频信号之间的传递函数记为h3；
扬声器102发出的声音到第二声音传感器模组104测量得到的音频信号之间的传递函数记为h4；
前馈滤波器的输入输出之间的传递函数记为h5；
反馈滤波器的输入输出之间的传递函数记为h6；
扬声器102发出的声音传播到耳膜202之间的声学传递函数记为h7；以及
噪声源300发出的声音传播到耳膜202之间的声学传递函数记为h8。
噪声源300发出的环境噪声记为S0；第一声音传感器模组103采集到的第一声音信号记为S1；第二声音传感器模组104采集到的第二声音信号记为S2；扬声器102发出的消噪信号记为S3；以及耳膜202处的环境噪声记为S4。需要说明的是，在本申请中，S4是指人耳实际听到的环境噪声，即经过降噪处理后在耳膜202处剩余的环境噪声。
由图5所示的声学传递过程，上述S0、S1、S2、S3和S4之间存在如下关系：
S4＝S3*h7+S0*h8      公式(0)
S3＝S1*h5      公式(1-1)
S3＝S2*h6     公式(1-2)
S3＝S1*h5+S2*h6      公式(1-3)
S1＝S0*h1+S3*h3     公式(2)
S2＝S3*h4+S0*h2      公式(3)
其中，上述公式(1-1)对应前馈降噪模式，上述公式(1-2)对应反馈降噪模式，上述公式(1-3)对应混合降噪模式。
下面以前馈降噪模式为例，分析前馈滤波器h5的设计原则。
在前馈降噪模式下，将上述公式(2)代入公式(1-1)中可以得到：
Figure PCTCN2022137185-appb-000001
将公式(4)代入公式(0)中，得到：
Figure PCTCN2022137185-appb-000002
在理想情况(扬声器102发出的声音不会泄漏到第一声音传感器模组103的情况)下，h3＝0，代入公式(5)得到：
S4＝S0*(h8+h1*h5*h7)     公式(6)
通常主动降噪技术的降噪目标是使得S4最小。基于公式(6)可知，在理想情况下h5需要实现对h1、h7以及h8的补偿。该情况下，第一声音传感器模组可以称为理想的前馈声音传感器模组，前馈滤波器可以称为理想的前馈滤波器。
而在非理想情况下，尤其是开放式声学设备中的第一声音传感器模组103不位于扬声器102的声学零点时，h3≠0，因此，降噪电路105可以通过内模控制的方式，测量得到扬声器102到第一声音传感器模组103之间的传递函数h3′，其中，h3′≈h3。在本申请中，考虑到传递函数h3′是测量得到的，与真正的传递函数h3之间可能存在一定的误差，因此，传递函数h3′也可以称为实测传递函数。降噪电路105在前馈降噪过程中，可以利用h3′对第一声音信号进行补偿，得到准环境噪声信号。进而，降噪电路105可以通过理想的前馈滤波器对准环境噪声信号进行滤波得到第一消噪信号。
在一些实施例中，可以采用如下方式测量得到h3′：降噪电路105向扬声器102发送测试音频信号，以使扬声器102发出对应的测试音频，所述测试音频被第一声音传感 器模组103采集到。降噪电路105获取第一声音传感器模组103采集到的采集音频信号，并根据测试音频信号和采集音频信号，确定传递函数h3′。例如，假设测试音频信号为Y1，采集音频信号为Y2，则h3′＝Y2/Y1。可见，降噪电路105通过控制扬声器102发送测试音频信号，即可测量得到h3′。这种测量h3′的实现方式简单，不会影响降噪电路105的降噪性能。
在一些实施例中，考虑到h3通常与声学设备100的佩戴位姿相关，同一声学设备100被不同用户佩戴时，对应的h3可能不同，并且，同一声学设备被同一用户多次佩戴时，对应的h3也可能不同。因此，降噪电路105可以在检测到声学设备100开机时，或者检测到声学设备100被用户佩戴时，执行上述测量过程，从而提高h3′的准确性。
在一些实施例中，降噪电路105在测量得到h3′后，可以采用如下方式生成准环境噪声信号：降噪电路105获取扬声器102对应的输入信号(即S3)，并对所述输入信号(S3)提供第一增益，得到第一增益信号，其中，第一增益为h3′。这样，第一增益信号为S3*h3′。进而，降噪电路105从第一声音传感器模组103获取第一声音信号(即S1＝S0*h1+S3*h3)，并在第一声音信号中减去第一增益信号，得到准环境噪声信号。其中，准环境噪声信号可以表示为：S1′＝S0*h1+S3*h3-S3*h3′。
S13：基于所述准环境噪声信号生成第一消噪信号。
在一些实施例中，继续参见图5，降噪电路105可以将准环境噪声信号S1′输入前馈滤波器(h5)，通过前馈滤波器对准环境噪声信号(S1′)进行滤波，得到第一消噪信号。其中，前馈滤波器被配置为对准环境噪声信号(S1′)的增益或相位中的至少一项进行调整，使得得到的第一消噪信号能够与耳膜202处和/或其周围部分空间中的至少部分环境噪声相抵。应理解的是，上述的前馈滤波器可以为理想的前馈滤波器，即上述的前馈滤波器的理想幅相响应可以基于公式(6)设计得到。
S14：向扬声器发送所述第一消噪信号，以使所述扬声器将所述第一消噪信号转换为第一消噪音频以降低耳膜处的所述环境噪声的音量。
如前所述，降噪电路105与扬声器102通信连接。降噪电路105在生成第一消噪信号之后，可以向扬声器102发送第一消噪信号。这样，扬声器102播放第一消噪信号对应的第一消噪音频，使得第一消噪音频与耳膜202处的环境噪声抵消或部分抵消，从而达到降噪的目的。
图6示出了根据本说明书的实施例提供的一种主动降噪方法的降噪效果的示意图。 如图6所示，曲线601和曲线602分别对应两种测试场景的降噪结果。其中，曲线601对应的测试过程如下：降噪电路105获取图3中的FF1(位于扬声器102的声学零点位置)采集到的第一声音信号，该第一声音信号中不含或者基本不含来自扬声器102的泄漏信号)。降噪电路105采用理想的前馈滤波器基于第一声音信号进行前馈降噪，得到曲线601所示的降噪结果。曲线602对应的测试过程如下：降噪电路105获取图3中的FF3(不位于扬声器102的声学零点位置，或位于扬声器102的声学零点之外)采集到的第一声音信号，该第一声音信号中包含来自扬声器102的泄漏信号。降噪电路105采用图4所示的主动降噪方法，先削减第一声音信号中的泄漏信号的成分得到准环境噪声信号，然后再采用理想的前馈滤波器基于准环境噪声信号进行前馈降噪。由图6可知，曲线601和曲线602两种降噪结果基本一致。由此可见，降噪电路105通过先削减第一声音信号中的泄漏信号的成分得到准环境噪声信号，再基于准环境噪声信号生成第一消噪信号，能够有效提高开放式声学设备的降噪效果。
上述图4所示的主动降噪方法P100中，降噪电路105在从第一声音传感器模组获取到第一声音信号之后，先从第一声音信号中削减泄露信号的成分生成准环境噪声信号，再基于准环境噪声信号进行前馈降噪以生成第一消噪信号。在一些实施例中，降噪电路105可以将上述削减的步骤和前馈降噪的步骤进行互换。具体的，降噪电路105在从第一声音传感器模组获取到第一声音信号(S1)之后，先对第一声音信号进行前馈降噪(h5)以生成中间消噪信号(S1*h5)。由于第一声音信号中包括环境噪声信号和泄露信号，因此降噪电路105对第一声音信号进行前馈降噪时，会对环境噪声信号和泄露信号同时进行前馈降噪，这样得到的中间消噪信号(S1*h5)中既包含了环境噪声信号的前馈降噪结果，也包含了泄露信号的前馈降噪结果。其中，泄露信号的前馈降噪结果可以通过如下方式估计得到：获取扬声器对应的输入信号(S3)，对输入信号提供第一增益(h3′)得到第一增益信号(S3*h3′)，应理解，第一增益信号S3*h3′可以视为泄露信号的估计值。基于前馈降噪参数(h5)对第一增益信号(S3*h3′)进行滤波，得到泄露信号的滤波结果(S3*h3′*h5)。进一步的，降噪电路105从中间消噪信号(S1*h5)中减掉泄露信号的前馈降噪结果(S3*h3′*h5)得到第一消噪信号(S1*h5-S3*h3′*h5)。需要说明的是，上述方式中，h3′为扬声器到第一声音传感器模组之间的传递函数，其测量方式可以参见前文相关内容的描述，此处不作赘述。
综上所述，本说明书提供的主动降噪方法P100，在第一声音信号中同时包括环境 噪声信号和泄漏信号的情况下，降噪电路105可以通过先削减第一声音信号中的泄漏信号的成分生成准环境噪声信号，再基于准环境噪声信号生成第一消噪信号，进而通过扬声器将第一消噪信号转换为第一消噪音频，从而达到降噪目的。由于降噪电路105在前馈降噪过程中，削减了第一声音信号中的泄漏信号的成分，降低了泄漏信号对前馈降噪的影响，因此，能够提高主动降噪的降噪效果。
通常，降噪电路105应以“最小化耳膜202处的环境噪声(S4)”作为降噪目标来设计/调整降噪电路105的降噪参数。在封闭式声学设备中，第二声音传感器模组104采集到的第二声音信号(S2)与耳膜202处的环境噪声(S4)相等或近似相等。因此，在封闭式声学设备中可以将“最小化第二声音信号(S2)”作为降噪目标。然而，在开放式声学设备中，由于扬声器102与耳膜202之间形成开放空间，第二声音传感器模组104测得的第二声音信号(S2)与耳膜202处的环境噪声(S4)之间不再是相等或近似相等的关系。
在本申请的研究过程中发现，S2与S4不再相等或近似相等的原因如下：结合图5所示的声学传递过程，第二声音传感器模组104测得的第二声音信号(S2)可以表示为公式(3)，耳膜202处的环境噪声(S4)可以表示为公式(0)，如下：
S2＝S3*h4+S0*h2     公式(3)
S4＝S3*h7+S0*h8      公式(0)
由上述公式(3)和公式(0)可见，S2和S4均可以视为两种声音信号的混合信号，其中，第一种声音信号来自于扬声器102发出的消噪信号(S3)，第二种声音信号来自噪声源300发出的环境噪声信号(S0)。针对第二种声音信号，考虑到通常情况下在待降噪频段内，噪声源300发出的声音到第二声音传感模组104测得的音频信号之间的传递函数(h2)与噪声源300发出的声音到耳膜202之间的传递函数(h8)相等或近似相等，即h2≈h8，因此，S2和S4中第二种声音信号的成分相当，S2和S4之间的差异主要来自于：S2中的消噪信号的成分(S3*h4)与S4中的消噪信号的成分(S3*h7)之间的差异。
在封闭式声学设备中，扬声器102发出的声音到第二声音传感器模组104测得的音频信号之间的传递函数(h4)与扬声器102发出的声音到耳膜202之间的传递函数(h7)相等或近似相等，即h4≈h7，因此，基于公式(3)得到的S2和基于公式(0)得到的 S4也是相等或近似相等的关系。而在开放式声学设备中，扬声器102发出的声音到第二声音传感器模组104测得的音频信号之间的传递函数(h4)与扬声器102发出的声音到耳膜202之间的传递函数(h7)不再相等或近似相等，因此，基于公式(3)得到的S2和基于公式(0)得到的S4也不再是相等或近似相等的关系。
能够理解，由于在开放式声学设备中，S2与S4不再是相等或近似相等的关系，因此，如果依然将“最小化S2”作为降噪目标的话，将使得降噪效果不佳。
为了解决上述技术问题，本申请的发明人在研究过程中提出如下技术构思：通过对声学设备100的结构以及各器件的位置进行特别设计，使得：虽然S4与S2并不相等，但是S4是可以基于S2估计得到的(或者说S4与S2之间具有相同的变化趋势)。这样，可以基于S2估计得到S4，并以最小化S4作为降噪目标进行主动降噪，或者，还可以基于“以最小化S2为降噪目标”所需的降噪参数，推导得到“以最小化S4为降噪目标”所需的降噪参数，从而提升主动降噪效果。
基于前述分析，S4与S2之间的差异主要来自于：S2中的消噪信号的成分(S3*h4)与S4中的消噪信号的成分(S3*h7)之间的差异。如果要实现基于S2估计得到S4的话，通常的考虑是需要分别获知h4和h7。然而，在发明人研究过程中发现，h7和h4均是与声学设备100的位姿强相关的量，即，在不同用户佩戴声学设备的情况下，h4互不相同，且h7也互不相同，甚至在同一用户多次佩戴声学设备的情况下，h4也互不相同，且h7也互不相同。并且，由于实际应用场景中，用户的耳膜202处不存在声学传感器，h7的测量难度较大，这对S4的估计造成较大困难。经过发明人的进一步研究发现，虽然h4和h7均与声学设备100的位姿强相关，但是，可以通过对第二声音传感器模组104和扬声器102的位置进行设计，使得：h4与h7之间满足第一预设关系，且所述第一预设关系独立于声学设备100的位姿。其中，所述第一预设关系独立于声学设备100的位姿是指，无论声学设备100以何种姿态被用户佩戴，h4与h7之间均满足所述第一预设关系。例如，当声学设备100被不同用户佩戴时，h4与h7之间均满足所述第一预设关系。又例如，当声学设备100被同一用户多次佩戴时，h4与h7之间均满足所述第一预设关系。
本申请对于所述第一预设关系的具体形式不作限定。在声学设备100的设计阶段，可以通过对大量用户、多次佩戴声学设备的过程进行测试，得到h4与h7之间的第一预设关系。在一些实施例中，上述第一预设关系可以为：h7/h4＝h9。需要说明的是，本 申请对于h9的取值不做限定。应理解，在h4与h7之间满足第一预设关系的情况下，S2与S4之间可能满足如下关系：S4中的消噪信号的成分(S3*h7)与S2中的消噪信号的成分(S3*h4)之间具有如下关系：(S3*h7)/(S3*h4)＝h9；或者，S2中消噪信号的成分(S3*h4)比S4中消噪信号的成分(S3*h7)的强度低xdB，其中，x的取值可以为1、2或其他任意数值。
需要说明的是，本申请对于第二声音传感器模组104和扬声器102的具体位置不作限定，只要二者的位置能够使得h4与h7之间满足第一预设关系，且第一预设关系独立于声学设备100的位姿即可。在一些实施例中，扬声器102可以设置在靠近耳道口的位置，且出音面(即出音端所在的表面)朝向耳道口。例如，由于声学设备100的形状和质量的分布，无论声学设备100以何种位姿被佩戴时，声学设备100的某个位置均靠近耳道口，因此可以将扬声器102设置在该位置。第二声音传感器模组104可以设置在扬声器102的出音面上。另外，在设计第二声音传感器模组104在出音面的具体位置时，可以考虑如下原则：(1)第二声音传感器模组104的采音端远离用户皮肤，(2)第二声音传感器模组104的采音端尽量靠近耳道口。应理解，采用上述方式确定出的扬声器102和第二声音传感器模组104的位置，能够使得h4与h7不易受到佩戴位姿的影响，即无论声学设备100以何种位姿被佩戴，h4与h7均满足相同的第一预设关系。另外，采用上述方式确定出的扬声器102和第二声音传感器模组104的位置，还能够使得第二声音传感器模组104采集到的第二声音信号S2与耳膜202处的环境噪声S4较为接近，且第二声音信号S2不易受到皮肤反射的影响，这样，基于第一预设关系和第二声音信号S2估计得到的S4更加准确。
在h4与h7之间满足第一预设关系，且所述第一预设关系独立于声学设备100的位姿的情况下，本申请提供一种主动降噪方法P200，无论声学设备100以何种位姿被用户佩戴，均能够基于第二声音信号(S2)和所述第一预设关系对降噪参数进行调整，从而提升主动降噪效果。所述主动降噪方法P200可以独立的应用于本申请提供的声学设备100上，也可以与本文其他部分描述的其他主动降噪方法相互结合。
图7示出了根据本说明书的实施例提供的另一种主动降噪方法P200的流程图。该主动降噪方法P200可以由声学设备100中的降噪电路105执行。例如，降噪电路105中的处理器107可以读取存储在其本地存储介质中的指令集，然后根据指令集的指示，执行本说明书描述的主动降噪方法P200。如图7所示，主动降噪方法P200可以包括：
S21：从第二声音传感器模组获取第二声音信号。
S22：基于所述第二声音信号和所述第一预设关系，对所述降噪电路的降噪参数进行调整。
在一些实施例中，降噪电路105可以基于第二声音信号(S2)和所述第一预设关系，确定耳膜202处的环境噪声(S4)。进而，降噪电路105以最小化耳膜202处的环境噪声(S4)为目标，对降噪参数进行调整。
在一些实施例中，降噪电路105可以采用如下方式估计得到S4：
(1)测量得到扬声器102发出的声音到第二声音传感器模组104测得的音频信号之间的第一传递函数h4′。
在一些实施例中，可以采用如下方式测量得到h4′：降噪电路105向扬声器102发送测试音频信号，以使扬声器102发出对应的测试音频，所述测试音频被第二声音传感器模组104采集到。降噪电路105获取第二声音传感器模组104采集到的采集音频信号，并根据测试音频信号和采集音频信号，确定第一传递函数h4′。例如，假设测试音频信号为Y1，采集音频信号为Y2，则h4′＝Y2/Y1。可见，降噪电路105通过控制扬声器102发送测试音频信号，即可测量得到h4′。这种测量h4′的实现方式简单，不会影响降噪电路105的降噪性能。在一些实施例中，考虑到h4通常与声学设备100的佩戴位姿相关，同一声学设备100被不同用户佩戴时，对应的h4可能不同，并且，同一声学设备被同一用户多次佩戴时，对应的h4也可能不同。因此，降噪电路105可以在检测到声学设备100开机时，或者检测到声学设备100被用户佩戴时，执行上述测量过程，从而提高h4′的准确性。
(2)基于所述第一传递函数、所述第一预设关系以及所述第二声音信号，确定所述耳膜处的环境噪声。
具体的，可以基于第一传递函数h4′和所述第一预设关系，确定出扬声器102发出的声音到耳膜202之间的第二传递函数h7′。
例如，假设所述第一预设关系为：h7/h4＝h9，则基于第一传递函数h4′与上述第一预设关系，可以得到第二传递函数h7′＝h4′*h9。
进而，可以基于第一传递函数h4′、第二传递函数h7′和S2，确定出S4，具体如下：
首先基于公式(3)，可以得到：
S0*h2＝S2-S3*h4     公式(12)
基于前面的分析，S2中的环境噪声的成分(S0*h2)与S4中环境噪声的成分(S0*h8)近似相等，即：
S0*h8≈S0*h2＝S2-S3*h4      公式(13)
将公式(13)代入到公式(0)中，得到：
S4≈S3*h7+(S2-S3*h4)     公式(14)
在公式(14)中，S3为扬声器102的输入信号，h4可以采用第一传递函数h4′代替，h7可以采用第二传递函数h7′代替，S2为第二声音传感器模组104采集到的第二声音信号。由此可见，降噪电路105基于第一传递函数h4′、第二传递函数h7′、第二声音信号S2、以及扬声器102的输入信号S3，可以估计得到S4。
上述主动降噪过程先基于第二声音信号(S2)和所述第一预设关系，确定出耳膜202处的环境噪声(S4)，再将最小化耳膜202处的环境噪声(S4)为降噪目标，提高了降噪目标的准确性，从而能够提高主动降噪的效果。
上述实施例在确定S4时基于如下假设：噪声源300发出的声音到第二声音传感模组104测得的音频信号之间的传递函数(h2)与噪声源300发出的声音到耳膜202之间的传递函数(h8)近似相等，即h2≈h8。发明人考虑到实际应用场景中，h2与h8通常并不是严格相等的关系，这导致上述实施例确定出的S4存在一定的误差。因此，为了进一步提高S4的精度，在确定S4的过程中还可以对h2和h8也进行考虑。然而，h2和h8也是与声学设备100的位姿相关的量，在不同用户佩戴声学设备的情况下，h2互不相同，h8互不相同，甚至在同一用户多次佩戴声学设备的情况下，h2也互不相同，h8也互不相同。因此，单独测量得到h2和h8具有一定的难度。经过发明人的进一步研究发现，在对第二声音传感器模组104和扬声器102的位置进行设计时，除了使h4与h7之间满足第一预设关系之外，还可以使h2与h8之间满足第二预设关系，且所述第二预设关系也独立于声学设备100的位姿。其中，所述第二预设关系独立于声学设备100的位姿是指，无论声学设备100以何种姿态被用户佩戴，h2与h8之间均满足所述第二预设关系。例如，当声学设备100被不同用户佩戴时，h2与h8之间均满足所述第二预设关系。又例如，当声学设备100被同一用户多次佩戴时，h2与h8之间均满足所述第二预设关系。
本申请对于所述第二预设关系的具体形式不作限定。在声学设备100的设计阶段， 可以通过对大量用户、多次佩戴声学设备的过程进行测试，得到h2/h1与h8/h1之间的关系，基于该关系可以得到h2与h8之间的第二预设关系。在一些实施例中，上述第二预设关系可以为：h8/h2＝h10。需要说明的是，本申请对于h10的取值不做限定。应理解，在h2与h8之间满足第二预设关系的情况下，S2与S4之间可能满足如下关系：S4中的环境噪声信号的成分(S0*h8)与S2中的环境噪声信号的成分(S0*h2)之间具有如下关系：(S0*h8)/(S0*h2)＝h10；或者，S2中的环境噪声信号的成分(S0*h2)比S4中的环境噪声信号的成分(S0*h8)的强度低ydB，其中，y的取值可以为1、2或其他任意数值。
在一些实施例中，在h4与h7之间满足第一预设关系，h2与h8之间满足第二预设关系，且所述第一预设关系和所述第二预设关系均独立于声学设备100的位姿的情况下，可以基于所述第一预设关系、所述第二预设关系以及S2估计得到S4。具体方式如下：
(1)测量得到扬声器102发出的声音到第二声音传感器模组104测得的音频信号之间的第一传递函数h4′。其中，第一传递函数h4′的测量过程可以参见前面相关内容的描述，此处不作赘述。
(2)基于所述第一传递函数、所述第一预设关系、所述第二预设关系以及所述第二声音信号，确定所述耳膜处的环境噪声。
具体的，可以基于第一传递函数h4′和所述第一预设关系，确定出扬声器102发出的声音到耳膜202之间的第二传递函数h7′。其中，第二传递函数h7′的确定过程可以参见前面相关内容的描述，此处不作赘述。
进而，可以基于所述第二预设关系、第一传递函数h4′、第二传递函数h7′和S2，确定出S4，具体如下：
首先基于公式(3)，可以得到：
S0*h2＝S2-S3*h4     公式(12)
基于第二预设关系，可以得到：
S0*h8＝S0*h2*h10＝(S2-S3*h4)*h10   公式(15)
将公式(15)代入到公式(0)中，得到：
S4＝S3*h7+(S2-S3*h4)*h10   公式(16)
在公式(16)中，S3为扬声器102的输入信号，h4可以采用第一传递函数h4′代 替，h7可以采用第二传递函数h7′代替，S2为第二声音传感器模组104采集到的第二声音信号，h10可以基于第二预设关系得到。由此可见，基于第一传递函数h4′、第二传递函数h7′、所述第二预设关系、第二声音信号S2、以及扬声器102的输入信号S3，可以确定出S4。
在估计得到S4之后，可以以最小化S4为降噪目标，对降噪电路105的降噪参数进行调整。在一些实施例中，降噪电路105可以包括前馈滤波器，该情况下，上述的降噪参数可以包括前馈滤波器的滤波参数。在一些实施例中，降噪电路105可以包括反馈滤波器，该情况下，上述的降噪参数可以包括反馈滤波器的滤波参数。在一些实施例中，降噪电路105可以包括前馈滤波器和反馈滤波器，该情况下，上述的降噪参数可以包括前馈滤波器的滤波参数或反馈滤波器的滤波参数中的至少一种。
在一些实施例中，上述前馈滤波器或反馈滤波器的滤波参数可以包括：滤波增益、滤波相位、或品质因子中的至少一种。其中，品质因子可以采用滤波器的中心频率F(单位为Hz)与-3dB带宽B(单位为Hz)的比值来表达，即品质因子Q＝F/B，描述了滤波器分离信号中相邻频率成分能力。品质因子越高，表明滤波器对相邻频率成分的分辨能力越高。
在一些实施例中，降噪电路105的降噪参数可以包括前馈滤波器的滤波增益。该情况下，为了便于描述，将“以最小化第二声音信号(S2)为降噪目标”所需的前馈滤波器的滤波增益称为第一滤波增益，并将“以最小化耳膜202处的环境噪声(S4)为降噪目标”所需的前馈滤波器的滤波增益称为第二滤波增益。那么，当h4与h7之间满足第一预设关系时，S2与S4的信号强度之间会存在某种关系，例如，S2的信号强度比S4的信号强度低xdB。该情况下，第一滤波增益与第二滤波增益之间同样满足该种关系。
举例说明，图8A示出了在第一用户佩戴声学设备的情况下采用不同的前馈滤波增益对耳膜处的环境噪声进行前馈降噪的频响曲线的示意图。图8B示出了在第一用户佩戴声学设备的情况下采用不同的前馈滤波增益对第二声音信号进行前馈降噪的频响曲线的示意图。其中，假设在h4与h7之间满足第一预设关系的情况下，第二声音信号(S2)比耳膜202处的环境噪声(S4)的强度低2dB。
参见图8A和图8B，在声学设备100被第一用户佩戴时，降噪电路105中的前馈滤波器分别采用不同的滤波增益(从0dB依次增加到4dB)进行主动降噪。在不同的滤波增益下，基于耳膜202处的环境噪声(S4)进行前馈降噪得到的频响曲线如图8A所示。在不同的滤波增益下，基于第二声音信号(S2)进行前馈降噪得到的频响曲线如图8B 所示。由图8A可知，如果以最小化耳膜202处的环境噪声(S4)作为降噪目标，则前馈滤波器所需的第二滤波增益为4dB。由图8B可知，如果以最小化第二声音信号(S2)作为降噪目标，则前馈滤波器所需的第一滤波增益为2dB。
图9A示出了在第二用户佩戴声学设备的情况下采用不同的前馈滤波增益对耳膜处的环境噪声进行前馈降噪的频响曲线的示意图。图9B示出了在用户B佩戴声学设备的情况下采用不同的前馈滤波增益对第二声音信号进行前馈降噪的频响曲线的示意图。其中，假设在h4与h7之间满足第一预设关系的情况下，第二声音信号(S2)比耳膜202处的环境噪声(S4)的强度低2dB。
参见图9A和图9B，在声学设备100被第二用户佩戴时，降噪电路105中的前馈滤波器分别采用不同的滤波增益(从0dB依次增加到4dB)进行主动降噪。在不同的滤波增益下，基于耳膜202处的环境噪声(S4)进行前馈降噪得到的频响曲线如图9A所示。在不同的滤波增益下，基于第二声音信号(S2)进行前馈降噪得到的频响曲线如图9B所示。由图9A可知，如果以最小化耳膜202处的环境噪声(S4)作为降噪目标，则前馈滤波器所需的第二滤波增益为3dB。由图8B可知，如果以最小化第二声音信号(S2)作为降噪目标，则前馈滤波器所需的第一滤波增益为1dB。
由图8A至图9B可见，“第一滤波增益与第二滤波增益之间的关系”与“第二声音信号(S2)的强度与耳膜202出的环境噪声(S4)的强度之间的关系”相同。也就是说，如果第二声音信号(S2)的强度比耳膜202处的环境噪声(S4)的强度低xdB，则第一滤波增益比第二滤波增益低xdB。
因此，降噪电路105还可以采用如下方式调整前馈滤波器的滤波增益：先以最小化第二声音信号(S2)作为降噪目标，确定出前馈滤波器的第一滤波增益。然后，降噪电路105基于所述第一滤波增益和所述第一预设关系，确定出上述第二滤波增益，并将前馈滤波器的当前滤波增益调整为所述第二滤波增益。例如，假设所述第一预设关系使得第二声音信号(S2)的强度比耳膜202处的环境噪声(S4)的强度低2dB。降噪电路105先以最小化第二声音信号(S2)为降噪目标，确定出第一滤波增益为2dB。然后，降噪电路105可以在第一滤波增益的基础上增加2dB，得到第二滤波增益为4dB。因此，将前馈滤波器的当前滤波增益调整为4dB。
在一些实施例中，声学设备100可以向用户提供多个工作模式，在每个工作模式下降噪电路105对应有默认降噪参数，且不同的工作模式对应的默认降噪参数不同。在一些实施例中，声学设备100上可以设置有交互控件，用户可以通过操作该交互控件切换 不同的工作模式。在一些实施例中，声学设备100可以提供交互界面，交互界面可以呈现在声学设备100的屏幕上，或者呈现在与声学设备100通信连接的目标设备上。用户可以通过交互界面选择不同的工作模式。在一些实施例中，上述多个工作模式分别对应不同的环境类型。用户可以通过交互的方式向声学设备100指示当前所处的环境类型，进而降噪电路105可以基于当前所处的环境类型切换至对应的工作模式。在一些实施例中，上述多个工作模式可以分别对应不同的用户类型。用户可以通过交互的方式向声学设备100指示自身所属的用户类型，进而降噪电路105可以基于用户所属的用户类型切换至对应的工作模式。
这样，在S22中，降噪电路105可以获取用户在多个工作模式中指示的目标工作模式，进而基于第二声音信号(S2)和所述第一预设关系，对目标工作模式对应的默认降噪参数进行调整。应理解，声学设备100通过提供多个工作模式，能够满足不同用户或不同环境下的降噪需求。
S23：基于所述调整后的降噪参数进行主动降噪。
在一些实施例中，降噪电路105还可以从第一声音传感器模组获取第一声音信号，并基于调整后的降噪参数对所述第一声音信号或所述第二声音信号中的至少一个进行滤波以生成消噪信号。进而，降噪电路105向扬声器发送所述消噪信号，以使所述扬声器将所述消噪信号转换为消噪音频以降低所述耳膜处的环境噪声的音量。
在一些实施例中，声学设备100工作在前馈降噪模式时，降噪电路105可以基于调整后的降噪参数，对第一声音信号进行滤波以生成消噪信号。例如，降噪电路105可以将第一声音信号输入前馈滤波器，通过前馈滤波器对第一声音信号进行滤波，得到消噪信号。在一些实施例中，第一声音信号同时包括来环境噪声信号和泄漏信号时，降噪电路105可以先通过削减第一声音信号中泄漏信号的成分生成准环境噪声信号，然后基于调整后的降噪参数，对所述准环境噪声信号进行滤波以得到消噪信号。一方面，由于在调整降噪参数时，保证了降噪目标的准确性，因此，基于调整后的降噪参数进行主动降噪，能够提高主动降噪的效果。另一方面，通过削减第一声音信号中泄漏信号的成分，降低了泄漏信号对前馈降噪过程的影响，能够进一步提高主动降噪的效果。
在一些实施例中，声学设备100工作在反馈降噪模式时，降噪电路105可以基于调整后的降噪参数，对第二声音信号进行滤波以生成消噪信号。例如，降噪电路105可以将第二声音信号输入反馈滤波器，通过反馈滤波器对第二声音信号进行滤波，得到消噪 信号。
在一些实施例中，声学设备100工作在混合降噪模式时，降噪电路105可以基于调整后的降噪参数对第一声音信号进行滤波，得到第一消噪信号。例如，降噪电路105将第一声音信号输入前馈滤波器，通过前馈滤波器对第一声音信号进行滤波，得到第一消噪信号。降噪电路105还可以基于调整后的降噪参数对第二声音信号进行滤波，得到第二消噪信号。例如，降噪电路105将第二声音信号输入反馈滤波器，通过反馈滤波器对第二声音信号进行滤波，得到第二消噪信号。进一步的，降噪电路105将第一消噪信号和第二消噪信号进行合成得到消噪信号。在一些实施例中，在第一声音信号同时包括环境噪声信号和泄漏信号的情况下，降噪电路105可以先通过削减第一声音信号中泄漏信号的成分生成准环境噪声信号，然后基于调整后的降噪参数，对所述准环境噪声信号进行滤波以得到第一消噪信号。一方面，由于在调整降噪参数时，保证了降噪目标的准确性，因此，基于调整后的降噪参数进行主动降噪，能够提高主动降噪的效果。另一方面，通过削减第一声音信号中泄漏信号的成分，降低了泄漏信号对前馈降噪过程的影响，能够进一步提高主动降噪的效果。
综上所述，本说明书提供的主动降噪方法P200中，由于扬声器102发出的声音到第二声音传感器模组104测得的音频信号之间的声学传递函数(h4)与扬声器102发出的声音到耳膜202之间的声学传递函数(h7)之间满足第一预设关系，且所述第一预设关系独立于声学设备100的位姿，因此，降噪电路105可以基于第二声音信号(S2)和所述第一预设关系，对降噪参数进行调整，并基于调整后的降噪参数进行主动降噪。由于降噪电路105基于第二声音信号(S2)和所述第一预设关系对降噪参数进行调整，使得调整后的降噪参数符合最本质的降噪目标，从而能够提升主动降噪的降噪效果。
如前所述，在一些实施例中，第一声音传感器模组103中可以包括一个声音传感器。该情况下，由于环境噪声可能从任意方向传来，因此可能出现如下情况：环境噪声在到达该声音传感器之前就已经到达扬声器102或者耳膜202。例如，假设该声音传感器设置在声学设备100的第一侧(例如朝向用户前方的一侧)，而噪声源300位于声学设备100的第二侧(例如朝向用户后方的一侧)，由于该声音传感器距离噪声源300较远，因此，噪声源300发出的环境噪声先到达扬声器102或耳膜202，然后才被该声音传感器采集到。这样，降噪电路105进行前馈降噪的因果性变差，使得前馈降噪的降噪效果变 差，尤其是某些频段(例如中高频段)的前馈降噪效果变差，甚至还可能会导致人耳听到的噪声提升。
为此，在一些实施例中，第一声音传感器模组103中可以包括多个声音传感器。为了便于描述，将第一声音传感器模组103中包括的声音传感器的数量记为N，N为大于或等于2的整数。N个声音传感器分别与支撑件101物理连接，且分布在相对于扬声器102远离耳膜的一侧。在不考虑扬声器102泄漏的情况下，每个声音传感器被配置为采集来自噪声源300的环境噪声并生成环境噪声信号。为了以示区分，在后文中，将每个声音传感器采集到的环境噪声信号称为个体环境噪声信号，将第一声音传感器模组103采集到的环境噪声信号称为综合环境噪声信号。
所述N个声音传感器相对于扬声器102上的目标点的方向不同。在一些实施例中，上述目标点可以为扬声器102的中心点或者出音点。由于N个声音传感器相对于所述目标点的方向不同，当环境噪声从不同方向传来时，N个声音传感器中均至少存在一个声音传感器能够先于扬声器102采集到环境噪声。
在一些实施例中，N＝2。图10示出了第一声音传感器模组中包括2个声音传感器的情况下各声音传感器的分布示意图。如图10所示，当N＝2时，第一声音传感器模组103可以包括：声音传感器1031和声音传感器1032。其中，上述2个声音传感器可以分别位于声学设备100朝向相反方向的两个侧面，或者说，上述2个声音传感器相对于所述目标点的方向相反。例如，在声学设备100被佩戴于用户头部时，声音传感器1031位于声学设备100的朝向用户前方的第一侧，声音传感器1032位于声学设备100的朝向用户后方的第二侧。这样，当环境噪声由用户前方的噪声源发出时，环境噪声到达声音传感器1031的相位(或者说声音传感器1031测得的个体环境噪声信号的相位)超前于环境噪声到达扬声器102的出音端的相位。当环境噪声由用户后方的噪声源发出时，环境噪声到达声音传感器1032的相位(或者说声音传感器1032测得的个体环境噪声信号的相位)超前于环境噪声到达扬声器102的出音端的相位。在一些实施例中，上述2个声音传感器可以位于扬声器102的声学零点位置。这样，2个声音传感器采集到的信号不含来自扬声器102的泄露信号，从而提升主动降噪效果。
在一些实施例中，N＝3。图11示出了第一声音传感器模组中包括3个声音传感器的情况下各声音传感器的分布示意图。如图11所示，当N＝3时，第一声音传感器模组103可以包括：声音传感器1031、声音传感器1032和声音传感器1033。其中，上述3个声 音传感器可以分布于声学设备100朝向不同方向的三个侧面。例如，在声学设备100被佩戴于用户头部时，声音传感器1031位于声学设备100的朝向用户前方的第一侧，声音传感器1032位于声学设备100的朝向用户后方的第二侧，声音传感器1033位于声学设备100的朝向地面的第三侧。这样，当环境噪声由用户前方的噪声源发出时，环境噪声到达声音传感器1031的相位(或者说声音传感器1031测得的个体环境噪声信号的相位)超前于环境噪声到达扬声器102的出音端的相位。当环境噪声由用户后方的噪声源发出时，环境噪声到达声音传感器1032的相位(或者说声音传感器1032测得的个体环境噪声信号的相位)超前于环境噪声到达扬声器102的出音端的相位。当环境噪声由声学设备下方的噪声源发出时，环境噪声到达声音传感器1033的相位(或者说声音传感器1033测得的个体环境噪声信号的相位)超前于环境噪声到达扬声器102的出音端的相位。在一些实施例中，上述3个声音传感器可以以三角形的形式分布于扬声器102的声学零点位置。这样，3个声音传感器采集到的信号中不含来自扬声器102的泄露信号，从而提升主动降噪效果。
需要说明的是，上述图10和图11仅为两种可能的分布方式。在实际设计时，N个声音传感器还可以采用其他的分布方式，本文对此不作一一举例说明。另外，本申请对于N的取值也不做具体限定，例如N的取值还可以等于4、5或其他任何整数。
在一些实施例中，上述N个声音传感器可以呈阵列排布，例如，线性阵列、平面阵列、球形阵列或其他阵列等。采用阵列方式排布也有利于降低降噪电路105内部的信号处理的复杂度，进而提升主动降噪性能。
所述N个声音传感器中的至少部分声音传感器可以为全向麦克风。全向麦克风对所有方向的环境噪声都具有较高的灵敏性，能够采集任意方向的环境噪声。所述N个声音传感器中的至少部分声音传感器也可以为指向性麦克风。指向性麦克风仅能够采集指定方向的环境噪声。比如，如图10所示，声音传感器1031的指向性可以为用户前方，被配置为采集用户前方传来的环境噪声，声音传感器1032的指向性可以为用户后方，被配置为采集用户后方传来的环境噪声。上述指向性麦克风可以包括但不限于：心型指向性麦克风、接近心型指向性麦克风、或者其他指向性麦克风。其中，上述指向性麦克风对不同频率的指向性可以相同，也可以不同。
在第一声音传感器模组103中包括N个声音传感器的情况下，本申请提供一种主动降噪方法P300，降噪电路105在进行主动降噪时，可以为N个声音传感器分配权重， 使得第一声音传感器模组103在任何方向上均具有相位领先性。该方案提高了前馈降噪的因果性，进而能够提升主动降噪效果。所述主动降噪方法P300可以独立的应用于本申请提供的声学设备100上，也可以与本文其他部分描述的其他主动降噪方法相互结合。
图12示出了根据本说明书的实施例提供的又一种主动降噪方法P300的流程图。该主动降噪方法P300可以由声学设备100中的降噪电路105执行。例如，当降噪电路105采用了图2所示的结构时，降噪电路105中的处理器107可以读取存储在其本地存储介质中的指令集，然后根据指令集的指示，执行本说明书描述的主动降噪方法P300。如图12所示，主动降噪方法P300可以包括：
S31：确定环境噪声来自的目标方向。
其中，目标方向是指环境噪声所来自的方向，即噪声源300的方向。在一些实施例中，可以将从扬声器102上的目标点指向噪声源300的射线的方向称为目标方向。
在一些实施例中，降噪电路105可以获取N个声音传感器采集到的N个个体环境噪声信号，并基于所述N个个体环境噪声信号估计得到环境噪声来自的目标方向。在一些实施例中，降噪电路105可以通过对所述N个个体环境噪声信号进行全频带的波达方向(Direction Of Arrival，DOA)分析，得到所述目标方向。该情况下，所述目标方向表示的是全频带的环境噪声(即总体环境噪声)的来波方向。
需要说明的是，本申请对于DOA算法不作具体限定，例如可以采用基于旋转不变技术的信号参数估计(Estimating Signal Parameter via Rotational Invariance Techniques，ESPRIT)算法、多重信号分类(Multiple Signal Classification，MUSIC)算法等中的一种或多种。
S32：基于所述目标方向，确定第一声音传感器模组中的N个声音传感器对应的N个权重，以使所述第一声音传感器模组基于所述N个权重测得的综合环境噪声信号的相位超前于所述环境噪声到达扬声器的出音端的相位。
在一些实施例中，所述综合环境噪声信号是基于所述N个权重对N个声音传感器采集到的N个个体环境噪声信号进行加权求和得到的信号。
结合图10进行举例说明。第一声音传感器模组103中包括声音传感器1031和声音传感器1032。其中，声音传感器1031采集到的个体环境噪声信号为：
Figure PCTCN2022137185-appb-000003
声音传感器1032采集到的个体环境噪声信号为：
Figure PCTCN2022137185-appb-000004
假设声音传感器1031的权重为α 1，声音传感器1032的权重为α 2，则第一声音传感 器模组103基于上述两个权重测得的综合环境噪声信号可以表示为：
Figure PCTCN2022137185-appb-000005
上述综合环境噪声信号的相位可以表示为：
Figure PCTCN2022137185-appb-000006
由此可见，降噪电路105可以基于目标方向，为N个声音传感器分别设置权重，使得上述综合噪声信号的相位超前于环境噪声到达扬声器102的出音端的相位。
在一些实施例中，第i个声音传感器对应的权重，与第i个声音传感器采集到的个体环境噪声信号的相位的领先情况相关。例如，第i个声音传感器采集到的个体环境噪声信号的相位相比环境噪声到达扬声器102的出音端的相位越超前，则第i个声音传感器对应的权重越大，反之，第i个声音传感器对应的权重越小。其中，i为小于或等于N的任意正整数。
在一些实施例中，假设第i个声音传感器相对于扬声器102上的目标点的方向与所述目标方向之间的夹角为θ i，则第i个声音传感器对应的权重与所述θ i负相关。也就是说，θ i越小(说明声音传感器相对于所述目标点的方向与目标方向之间的偏差越小)，权重越大，θ i越大(说明声音传感器相对于所述目标点的方向与目标方向之间的偏差越大)，权重越小。其中，i为小于或等于N的任意正整数。
结合图10进行举例说明，假设环境噪声来自于用户前方，则声音传感器1031的权重大于声音传感器1032的权重，这样，在进行主动降噪时，主要是声音传感器1031起主要作用，能够保证相位领先性。假设环境噪声来自于用户后方，则声音传感器1032的权重大于声音传感器1031的权重，这样在进行主动降噪时，主要是声音传感器1032起主要作用，也能够保证相位领先性。
S33：基于所述N个声音传感器采集到的N个个体环境噪声信号和所述N个权重，生成第一消噪信号。
在一些实施例中，降噪电路105可以包括N个前馈滤波器，与N个声音传感器一一对应。其中，第i个前馈滤波器连接第i个声音传感器和扬声器102，并被配置为对第i个声音传感器采集到的个体环境噪声信号进行滤波。所述i为小于或等于N的任意正整数。也就是说，降噪电路105中的N个前馈滤波器为并联关系。
由于N个前馈滤波器为并联关系，在主动降噪过程中，不会导致滤波器阶数的增加，也不会增加延迟。另外，在此基础上，上述N个并联关系的前馈滤波器还有助于增加滤 波复杂度，比如N个前馈滤波器可以负责不同频带的降噪，从而增强前馈降噪能力。
图13示出了根据本说明书的实施例提供的另一种声学设备的主动降噪原理示意图。如图13所示，假设第一声音传感器模组103包括声音传感器1031和声音传感器1032，降噪电路中包括前馈滤波器h51和前馈滤波器h52。其中，前馈滤波器h51连接声音传感器1031和扬声器102，前馈滤波器h52连接声音传感器1032和扬声器102。
继续参见图13，假设：
噪声源300发出的声音到声音传感器1031测量得到的音频信号之间的传递函数记为h11；
噪声源300发出的声音到声音传感器1032测量得到的音频信号之间的传递函数记为h12；
扬声器102发出的声音到耳膜202之间的声学传递函数记为h7；以及
噪声源300发出的声音到耳膜202之间的声学传递函数记为h8。
噪声源300发出的噪声信号记为S0；声音传感器1031采集到的个体环境噪声信号记为S11；声音传感器1032采集到的个体环境噪声信号记为S12；扬声器102发出的消噪信号记为S3；以及耳膜202接收到的噪声信号记为S4。
由图13所示的声学传递过程，上述S0、S11、S12、S3和S4之间存在如下关系：
S4＝S0*h8+S3*h7     公式(0)
S3＝S11*h51+S12*h52     公式(7)
S11＝S0*h11      公式(8)
S12＝S0*h12       公式(9)
把公式(8)和公式(9)代入公式(7)中得到：
S3＝S0*h11*h51+S0*h12*h52    公式(10)
将公式(10)代入公式(0)中得到：
S4＝S0*h8+S0*(h11*h51+h12*h52)*h7     公式(11)
由公式(11)可见，前馈降噪效果由h51和h52共同决定。
在一些实施例中，降噪电路105进行主动降噪时，可以基于声音传感器1031的权重，对前馈滤波器h51的滤波参数进行调整，并通过调整后的前馈滤波器h51对声音传感器1031采集到的个体环境噪声信号S11进行滤波，生成个体消噪信号。并且，降噪电 路105还可以基于声音传感器1032的权重，对前馈滤波器h52的滤波参数进行调整，并通过调整后的前馈滤波器h52对声音传感器1032采集到的个体环境噪声信号S12进行滤波，生成个体消噪信号。进一步的，降噪电路105将两个前馈滤波器生成的两个个体消噪信号进行合成，得到第一消噪信号。
在一些实施例中，上述对前馈滤波器h51或前馈滤波器h52的滤波参数进行调整，可以包括：对前馈滤波器h51或前馈滤波器h52的滤波增益进行调整。例如，可以将声音传感器1031的权重与前馈滤波器h51的当前滤波增益进行相乘，得到前馈滤波器h51调整后的滤波增益。可以将声音传感器1032的权重与前馈滤波器h52的当前滤波增益进行相乘，得到前馈滤波器h52调整后的滤波增益。
应理解，降噪电路105通过基于N个权重对N个前馈滤波器的滤波参数进行调整，使得主动降噪过程中，权重较高的声音传感器(具有较高的相位领先性的声音传感器)及其对应的前馈滤波器对整体降噪的贡献较高，权重较低的声音传感器(具有较低的相位领先性的声音传感器)及其对应的前馈滤波器对整体降噪的贡献较低，从而能够提升主动降噪效果。
在一些实施例中，上述N个声音传感器可以为N个具有不同指向性的指向性麦克风。继续参见图13，假设声音传感器1031的指向性为用户前方，声音传感器1032的指向性为用户后方。当环境噪声来自于用户前方时，上述两个声音传感器的指向性使得h11远大于h12(即，h11>>h12)，根据上述公式(11)可见，主动降噪过程中主要是声音传感器1031在起作用，因此，第一声音传感器模组103具有相位领先性，从而能够提升主动降噪效果。当环境噪声来自于用户后方时，上述两个声音传感器的指向性使得h11远小于h12(即，h11<<h12)，根据上述公式(11)可见，主动降噪过程中主要是声音传感器1032在起作用，因此，第一声音传感器模组103具有相位领先性，从而能够提升主动降噪效果。
由此可见，在N个声音传感器具有不同指向性的情况下，N个声音传感器的不同指向性，使得主动降噪过程自动选择了最优的声音传感器，而无需再对前馈滤波器的滤波参数进行调整，即可实现第一声音传感器模组在各个方向的相位领先性。
S34：向扬声器发送所述第一消噪信号，以使所述扬声器将所述第一消噪信号转换为第一消噪音频以降低耳膜处的所述环境噪声的音量。
应理解，上述S31至S34描述的是对全频带的环境噪声进行来波方向估计，并基于 估计得到的目标方向进行全频带的主动降噪。在一些实施例中，降噪电路105在估计目标方向时，还可以分子频带进行估计。例如，将全频带划分为M个子频带，环境噪声包括对应于M个子频带的M个子频带噪声。降噪电路105可以针对每个子频带，分别估计得到M个子频带噪声的来波方向。该情况下，S31中得到的目标方向包括了对应于M个子频带的M个来波方向。需要说明的是，本申请对于M个子频带的划分方式不作限定。在一些实施例中，上述M个子频带可以包括：低频带(例如0～150Hz)、中频带(例如150～500Hz)和高频带(例如500～2000Hz)。
在一些实施例中，降噪电路105可以获取N个声音传感器采集到的N个个体环境噪声信号，进而采用如下方式估计得到第j个子频带的来波方向：从所述N个个体环境噪声信号中分别提取对应于第j个子频带的子频带噪声信号，得到对应于第j个子频带的N个子频带噪声信号，通过对所述N个子频带噪声信号进行DOA分析，得到对应于第j个子频带的来波方向。其中，j为小于或等于M的任意正整数。
在得到对应于M个子频带的M个来波方向后，降噪电路105可以基于每个子频带分别进行主动降噪。具体而言，降噪电路105针对第j个子频带，基于对应于第j个子频带的来波方向，确定N个声音传感器对应的N个子频带权重，以使第一声音传感器模组103基于上述N个子频带权重测得的综合子频带噪声信号的相位超前与第j个子频带的环境噪声到达扬声器102的出音端的相位。其中，所述综合子频带噪声信号是基于所述N个子频带权重对所述N个声音传感器采集到的对应于第j个子频带的子频带噪声信号进行加权求和得到的信号。进一步的，降噪电路105基于所述N个声音传感器采集到的对应于第j个子频带的子频带噪声信号，以及N个子频带权重，生成对应于第j个子频带的N个个体子频带消噪信号。降噪电路将所述N个个体子频带消噪信号进行叠加，得到对应于第j个子频带的子频带消噪信号。其中，所述j为小于或等于M的任意正整数。降低电路105针对M个子频带分别执行上述过程，得到对应于M个子频带的M个子频带消噪信号。进一步的，降噪电路105向扬声器102发送所述M个子频带消噪信号，以使扬声器102将所述M个子频带消噪信号转换为消噪音频以降低耳膜202处的环境噪声的音量。
应理解，针对每个子频带进行主动降噪的过程，与前文描述的针对全频带的主动降噪过程类似，此处不作赘述。需要说明的是，每个前馈滤波器可以包括对应于M个子频带的M个滤波单元，在针对第j个子频带进行主动降噪时，可以基于权重对前馈滤波 器中第j个滤波单元对应的滤波参数进行调整，例如，调整第j个滤波单元对应的滤波增益。
图14示出了根据本说明书的实施例提供的一组频响曲线的示意图。如图14所示，曲线141示意的是声学设备100采用单个声音传感器FF1并配合前馈滤波器的频响情况，曲线142示意的是声学设备100采用单个声音传感器FF2并配合前馈滤波器的频响情况，曲线143示意的是声学设备100同时采用声音传感器FF1和声音传感器FF2，并配合两个并列的前馈滤波器的频响情况。根据曲线141和曲线142可见，单独的声音传感器FF1和单独的声音传感器FF2分别在不同的频带下起到降噪效果。根据曲线143可见，将声音传感器FF1和声音传感器FF2结合使用后能够在更宽的频带下起到降噪效果，并达到更深的降噪深度。
如前所述，在开放式声学设备中，声音传感器采集到的环境噪声信号中会存在泄漏信号(即来自扬声器102的泄漏信号)。声学设备100通过在第一声音传感器103中设置多个声音传感器，能够一定程度上降低上述泄漏。图15示出了根据本说明书的实施例提供的又一组频响曲线的示意图。如图15所示，曲线153示意的是声学设备100同时采用声音传感器FF1和声音传感器FF2，并配合两个并列的前馈滤波器进行降噪的情况下的频响情况。其中，曲线151示意的是FF1及其对应的前馈滤波器的频响情况，曲线152示意的是FF2及其对应的前馈滤波器的频响情况。由图15可见，在采用两个声音传感器的情况下，每个声音传感器所需的前馈滤波增益明显小于采用单个声音传感器实现相同滤波效果时所需的前馈滤波增益。前馈滤波增益的降低能够使得泄漏降低，从而避免由于泄漏带来的系统发散问题、以及部分用户佩戴声学设备出现的增噪问题等。
综上所述，本说明书提供的主动降噪方法P300中，在第一声音传感器模组103包括N个声音传感器的情况下，降噪电路105在进行主动降噪时，可以基于环境噪声来自的目标方向，确定N个声音传感器对应的N个权重，以使第一声音传感器模组103基于所述N个权重测得的综合环境噪声信号的相位超前于环境噪声到达扬声器的出音端的相位。然后，降噪电路105基于N个声音传感器采集到的N个个体环境噪声信号和所述N个权重生成第一消噪信号，并向扬声器102发送第一消噪信号。由此可见，该方案通过引入N个声音传感器，并对N个声音传感器分配权重，使得无论环境噪声来自哪个方向，均能保证第一声音传感器模组103相对于扬声器102的出音端具有相位领先性，提高了前馈降噪的因果性，进而能够提升主动降噪效果，尤其能够提高高频的降噪 性能。另外，采用多个声音传感器相较于采用单个声音传感器，还能够降低增益，进而使得开放式场景下的某些频带(例如高频)的泄漏降低，从而避免由于上述频带的泄漏带来的系统发散问题、以及部分用户佩戴声学设备出现的增噪问题等。进一步的，该方案通过以子频带为粒度分别估计来波方向，并针对每个子频带分别进行主动降噪，有助于提高每个子频带的降噪深度，从而进一步提升主动降噪的效果。
通常，声学设备100在开启主动降噪功能后，基于预先设计的降噪参数，在全频带范围内进行主动降噪。而在实际应用中，由于声学设备100所处的外部环境多种多样，上述预先设计的降噪参数，通常无法适用于对多种外部环境中的噪声进行主动降噪。例如，在一些特殊的外部环境中声学设备的降噪效果可能较差，或者可能存在扬声器102破音的情况。
为此，降噪电路105可以提供多种降噪模式。这样，在主动降噪过程中，降噪电路105可以基于外部环境的噪声情况自适应地在多种降噪模式中选择目标降噪模式，并执行目标降噪模式。其中，自适应地选择目标降噪模式是指，可以根据外部环境的噪声情况，自主地、灵活地、智能地、和/或适应性地切换降噪模式。应理解，上述切换降噪模式的过程是降噪电路105自动执行的，无需用户的手动参与。
在一些实施例中，上述多种降噪模式可以包括：消极降噪模式、防破音降噪模式、窄带降噪模式或普通降噪模式中的至少一种。
其中，在消极降噪模式下，声学设备100的主动降噪功能被关闭。
在普通降噪模式下，声学设备100的主动降噪功能被开启，降噪电路105采用预先设计的降噪参数，基于第一声音信号或第二声音信号中的至少一种，在全频带范围内进行主动降噪。
在窄带降噪模式下，声学设备100的主动降噪功能被开启。主动降噪过程包括：降噪电路105基于第一声音信号确定目标频带，所述目标频带内的能量集中度超过预设阈值。其中，目标频带内的能量集中度是指在目标频带内噪声信号能量的集中程度。在一些实施例中，目标频带对应的带宽小于预设带宽，因此所述目标频带可以称为窄带。进一步的，降噪电路105可以基于第一声音信号或第二声音信号中的至少一种，在目标频带(窄带)内进行主动降噪。
在一些实施例中，降噪电路105在确定出目标频带之后，可以基于目标频带调整降 噪电路105的降噪参数，调整后的降噪参数可以指定重点对目标频带进行主动降噪(例如目标频带的降噪深度大于其他频带的降噪深度)，或者，调整后的降噪参数可以指定只对目标频带进行主动降噪而不对其他频带进行主动降噪。在一些实施例中，上述“调整降噪电路105的降噪参数”可以包括：将降噪电路105中的全频带滤波器转换为窄带滤波器。上述实施例通过基于目标频带调整降噪参数，可以增加目标频带内的降噪深度，提升目标频带内的降噪效果。
在防破音降噪模式下，声学设备100的主动降噪功能被开启。主动降噪过程包括：降噪电路105基于第一声音信号或第二声音信号中的至少一种生成消噪信号，并使得所述消噪信号的幅值位于扬声器102支持的幅值范围内。进一步的，降噪电路105向扬声器102发送消噪信号，以使扬声器102将消噪信号转换为消噪音频以降低耳膜202处的环境噪声的音量。其中，上述幅值范围是指扬声器102在能够正常发声而不破音(broken sound)的情况下所支持播放的信号幅值范围。所述破音即指扬声器振膜的震动超过其线性范围，从而导致声音走样严重的现象。当输入至扬声器102的信号的幅值超出上述幅值范围时，会导致扬声器102破音。当输入至扬声器102的信号的幅值位于所述幅值范围内时，不会导致扬声器102破音。应理解，由于降噪电路105在生成消噪信号时，保证了消噪信号的幅值位于扬声器102支持的幅值范围内，因此，能够避免扬声器102破音。
在一些实施例中，降噪电路105可以采用如下方式生成消噪信号，以使得消噪信号的幅值位于扬声器102支持的幅值范围内：降噪电路105对第一声音信号或第二声音信号中的至少一种进行滤波，得到候选消噪信号。上述滤波的过程已在前文相关部分描述，此处不作赘述。进一步的，降噪电路105基于所述幅值范围，对候选消噪信号的幅值进行修正，使得修正后的幅值位于所述幅值范围内，并将修正得到的信号作为消噪信号。在一些实施例中，降噪电路105的输出端(即，降噪电路105与扬声器102的接口处)可以设置有动态范围控制(Dynamic range control，DRC)器。所述动态范围控制器被配置为对输入信号的幅值进行调整，以使得输出信号的幅值位于所述幅值范围内。该情况下，降噪电路105得到候选消噪信号之后，将候选消噪信号输入动态范围控制器，通过动态范围控制器对候选消噪信号的幅值进行修正，得到消噪噪声。
该方式中，降噪电路105不需要对原有的降噪参数进行调整，而只需要增加后置的幅值修正环节(例如增加动态范围控制器)，即可避免扬声器102破音。
在一些实施例中，降噪电路105可以采用如下方式生成消噪信号，以使得消噪信号的幅值位于扬声器102支持的幅值范围内：降噪电路105基于所述第一声音信号，调整降噪电路105对应的滤波增益，以使滤波后得到的输出信号的幅值位于所述幅值范围内。进一步的，降噪电路105基于调整后的降噪参数，对第一声音信号或第二声音信号中的至少一种进行滤波，得到所述消噪信号。
该方式中，降噪电路105只需要调整滤波增益，即可使得消噪信号的幅值位于所述幅值范围内，而不需要对降噪电路105的电路结构进行变更。
在一些实施例中，在所述调整后的滤波增益中，第一预设频段对应的第一滤波增益小于第二预设频段对应的第二滤波增益。在一些实施例中，所述第一预设频段中的频率低于所述第二预设频段中的频率。在一些实施例中，所述第一预设频段中的频率低于预设频率，其中上述预设频率可以为500Hz、200Hz、150Hz或者其他频率值。在一些实施例中，上述第一预设频段可以为低频段(例如频率小于150Hz的频段)。由于第一预设频段对应较小的滤波增益，能够使得滤波后的消噪信号在第一预设频段对应的幅值较小，从而避免扬声器102在第一预设频段发生破音。
在一些实施例中，降噪电路105在调整滤波增益时，可以在默认滤波增益的基础上，降低第一预设频段对应的第一滤波增益，而保持第二预设频段对应的第二滤波增益不变。这样，能够在不降低第二预设频段对应的降噪效果的情况下，防止扬声器102破音。
在声学设备100提供多种降噪模式的情况下，本申请提供一种主动降噪方法P400，能够基于当前环境的噪声情况，自适应的切换适合当前环境的降噪模式，从而声学设备100能够在不同环境下均具有较好的降噪效果。所述主动降噪方法P400可以独立的应用于本申请提供的声学设备100上，也可以与本文其他部分描述的其他主动降噪方法相互结合。
图16示出了根据本说明书的实施例提供的又一种主动降噪方法P400的流程图。该主动降噪方法P400可以由声学设备100中的降噪电路105执行。例如，降噪电路105中的处理器107可以读取存储在其本地存储介质中的指令集，然后根据指令集的指示，执行本说明书描述的主动降噪方法P400。如图16所示，主动降噪方法P400可以包括：
S41：从第一声音传感器模组获取第一声音信号。
S42：基于所述第一声音信号，在声学设备的多个降噪模式中自适应地选择目标降噪模式。
在一些实施例中，降噪电路105可以基于第一声音信号的强度或带宽类型中的至少一项，在多个降噪模式中自适应的选择目标降噪模式。其中，第一声音信号的带宽类型可以分为如下两种：窄带类型和非窄带类型。窄带类型表示第一声音信号所占带宽小于预设带宽。相对于非窄带类型而言，窄带类型的信号能量集中在较窄的频带范围内。
在一些实施例中，降噪电路105自适应的选择目标降噪模式的过程可以包括下述S42-1、S42-2、S42-3中的至少一项。
S42-1：确定所述第一声音信号的强度小于或等于第二强度阈值，在所述多个降噪模式中选择消极降噪模式。
其中，第二强度阈值可以对应较安静环境中噪声强度的上限。例如，第二强度阈值可以为40dB。也就是说，在外部环境的噪声强度较小(例如小于40dB)时，降噪电路105选择消极降噪模式，关闭主动降噪功能。这样可以降低声学设备100的功耗。
S42-2：确定所述第一声音信号的强度大于或等于第一强度阈值，在所述多个降噪模式中选择防破音降噪模式。
其中，第一强度阈值大于第二强度阈值。例如，第一强度阈值可以为90dB。当外部环境的噪声较高(例如大于或等于90dB)时，降噪电路105可以选择防破音降噪模式。这样可以避免扬声器102破音。
S42-3：确定所述第一声音信号的强度大于第二强度阈值，且所述第一声音信号的带宽类型为窄带类型，在所述多个降噪模式中选择窄带降噪模式。
其中，“第一声音信号的强度大于第二强度阈值”为开启主动降噪功能的条件，在此基础上，若第一声音信号的带宽类型为窄带类型的话，则降噪电路105选择窄带降噪模式。这样可以仅针对第一声音信号能量集中的目标频带进行主动降噪，而不必在全频带范围内进行主动降噪，有助于增加目标频带内的降噪深度，提升主动降噪效果。
在一些实施例中，降噪电路105自适应的选择目标降噪模式的判断逻辑可以如下：降噪电路105先判断第一声音信号的强度是否小于第二强度阈值，若是，则选择消极降噪模式。若否，则开启主动降噪功能。之后，降噪电路105分别判断下述两个条件是否满足，条件1：第一声音信号的强度大于或等于第一强度阈值，条件2：第一声音信号的带宽类型为窄带类型。此时判断结果包括如下四种情况：若仅条件1满足，则选择防破音降噪模式；若仅条件2满足，则选择窄带降噪模式；若条件1和条件2均满足，则可以同时选择防破音降噪模式和窄带降噪模式，若条件1和条件2均不满足，则选择普 通降噪模式。
在一些实施例中，当第一声音信号同时包括环境噪声信号和泄漏信号时，降噪电路105可以先削减第一声音信号中的泄漏信号的成分生成准环境噪声信号，进而，基于准环境噪声信号，在多个降噪模式中自适应地选择目标降噪模式。其中，上述削减第一声音信号中的泄漏信号的成分的方式已在前文进行介绍，此处不作赘述。
降噪电路105通过削减第一声音信号中的泄漏信号的成分，使得得到的准环境噪声信号与实际环境噪声更加接近，因此，基于准环境噪声信号来自适应地选择目标降噪模式，使得选择出的目标降噪模式更加符合当前环境，从而提高降噪效果。
S43：执行所述目标降噪模式。
在一些实施例中，声学设备100工作在前馈降噪模式下，降噪电路105基于所述第一声音信号执行目标降噪模式。在一些实施例中，声学设备100工作在反馈降噪模式下，降噪电路105基于第二声音信号执行目标降噪模式。在一些实施例中，声学设备100工作在混合降噪模式下，降噪电路105基于第一声音信号和第二声音信号执行目标降噪模式。
综上所述，本说明书提供的主动降噪方法P400，可以基于声学设备100所处的外部环境的噪声情况自适应地调整降噪模式，使得声学设备100的主动降噪过程更加符合当前环境的噪声情况，有助于提高声学设备100的整体性能。例如，在当前环境的噪声较低时，声学设备100可以关闭主动降噪功能，以降低功耗；在当前环境的噪声较高时，声学设备100可以选择防破音降噪模式，避免扬声器102破音；在当前环境的噪声为窄带类型时，声学设备100可以选择窄带降噪模式，以增加降噪深度，提升降噪效果。
在声学设备100提供多种降噪模式的情况下，本申请还提供另一种主动降噪方法，可以由降噪电路105执行。该主动降噪方法中，降噪电路105可以获取用户的指令，并根据用户的指令在多个降噪模式中选择目标降噪模式，进而执行目标降噪模式。例如，声学设备100上可以设置有交互控件，用户可以通过该交互控件切换不同的降噪模式。又例如，声学设备100可以提供交互界面，该交互界面可以呈现在声学设备100的屏幕上，或者呈现在与声学设备100通信连接的目标设备上，用户可以通过交互界面选择不同的降噪模式。在一些实施例中，上述用户的指令可以指示具体的降噪模式，这样，降噪电路105可以将上述指令所指示的降噪模式确定为目标降噪模式。在一些实施例中，上述用户的指令可以具体指示用户所处的环境噪声情况，降噪电路105可以基于上述指 令所指示的环境噪声情况在多个降噪模式中选择目标降噪模式。这样，用户可以根据自己的喜好和/或当前所处的环境噪声情况，自主选择适合的主动降噪模式，从而满足不同用户的个性化需求。
本说明书另一方面提供一种非暂时性存储介质，存储有至少一组用来进行主动降噪的可执行指令。当所述可执行指令被处理器执行时，所述可执行指令指导所述处理器实施本说明书所述的主动降噪方法的步骤。在一些可能的实施方式中，本说明书的各个方面还可以实现为一种程序产品的形式，其包括程序代码。当所述程序产品在声学设备100上运行时，所述程序代码用于使声学设备100执行本说明书描述的主动降噪方法的步骤。用于实现上述方法的程序产品可以采用便携式紧凑盘只读存储器(CD-ROM)包括程序代码，并可以在声学设备100上运行。然而，本说明书的程序产品不限于此，在本说明书中，可读存储介质可以是任何包含或存储程序的有形介质，该程序可以被指令执行系统使用或者与其结合使用。所述程序产品可以采用一个或多个可读介质的任意组合。可读介质可以是可读信号介质或者可读存储介质。可读存储介质例如可以为但不限于电、磁、光、电磁、红外线、或半导体的系统、装置或器件，或者任意以上的组合。可读存储介质的更具体的例子包括：具有一个或多个导线的电连接、便携式盘、硬盘、随机存取存储器(RAM)、只读存储器(ROM)、可擦式可编程只读存储器(EPROM或闪存)、光纤、便携式紧凑盘只读存储器(CD-ROM)、光存储器件、磁存储器件、或者上述的任意合适的组合。所述计算机可读存储介质可以包括在基带中或者作为载波一部分传播的数据信号，其中承载了可读程序代码。这种传播的数据信号可以采用多种形式，包括但不限于电磁信号、光信号或上述的任意合适的组合。可读存储介质还可以是可读存储介质以外的任何可读介质，该可读介质可以发送、传播或者传输用于由指令执行系统、装置或者器件使用或者与其结合使用的程序。可读存储介质上包含的程序代码可以用任何适当的介质传输，包括但不限于无线、有线、光缆、RF等等，或者上述的任意合适的组合。可以以一种或多种程序设计语言的任意组合来编写用于执行本说明书操作的程序代码，所述程序设计语言包括面向对象的程序设计语言—诸如Java、C++等，还包括常规的过程式程序设计语言—诸如“C”语言或类似的程序设计语言。程序代码可以完全地在声学设备100上执行、部分地在声学设备100上执行、作为一个独立的软件包执行、部分在声学设备100上部分在远程计算设备上执行、或者完全在远程计算设备上执行。
上述对本说明书特定实施例进行了描述。其他实施例在所附权利要求书的范围内。 在一些情况下，在权利要求书中记载的动作或步骤可以按照不同于实施例中的顺序来执行并且仍然可以实现期望的结果。另外，在附图中描绘的过程不一定要求示出特定顺序或者连续顺序才能实现期望的结果。在某些实施方式中，多任务处理和并行处理也是可以的或者是可能有利的。
综上所述，在阅读本详细公开内容之后，本领域技术人员可以明白，前述详细公开内容可以仅以示例的方式呈现，并且可以不是限制性的。尽管这里没有明确说明，本领域技术人员可以理解本说明书需求囊括对实施例的各种合理改变，改进和修改。这些改变，改进和修改旨在由本说明书提出，并且在本说明书的示例性实施例的精神和范围内。
此外，本说明书中的某些术语已被用于描述本说明书的实施例。例如，“一个实施例”，“实施例”和/或“一些实施例”意味着结合该实施例描述的特定特征，结构或特性可以包括在本说明书的至少一个实施例中。因此，可以强调并且应当理解，在本说明书的各个部分中对“实施例”或“一个实施例”或“替代实施例”的两个或更多个引用不一定都指代相同的实施例。此外，特定特征，结构或特性可以在本说明书的一个或多个实施例中适当地组合。
应当理解，在本说明书的实施例的前述描述中，为了帮助理解一个特征，出于简化本说明书的目的，本说明书将各种特征组合在单个实施例、附图或其描述中。然而，这并不是说这些特征的组合是必须的，本领域技术人员在阅读本说明书的时候完全有可能将其中一部分设备标注出来作为单独的实施例来理解。也就是说，本说明书中的实施例也可以理解为多个次级实施例的整合。而每个次级实施例的内容在于少于单个前述公开实施例的所有特征的时候也是成立的。
本文引用的每个专利，专利申请，专利申请的出版物和其他材料，例如文章，书籍，说明书，出版物，文件，物品等，可以通过引用结合于此。用于所有目的全部内容，除了与其相关的任何起诉文件历史，可能与本文件不一致或相冲突的任何相同的，或者任何可能对权利要求的最宽范围具有限制性影响的任何相同的起诉文件历史。现在或以后与本文件相关联。举例来说，如果在与任何所包含的材料相关联的术语的描述、定义和/或使用与本文档相关的术语、描述、定义和/或之间存在任何不一致或冲突时，使用本文件中的术语为准。
最后，应理解，本文公开的申请的实施方案是对本说明书的实施方案的原理的说明。其他修改后的实施例也在本说明书的范围内。因此，本说明书披露的实施例仅仅作为示 例而非限制。本领域技术人员可以根据本说明书中的实施例采取替代配置来实现本说明书中的申请。因此，本说明书的实施例不限于申请中被精确地描述过的实施例。

Claims (21)

  1. 一种开放式可穿戴声学设备，其特征在于，包括：
    支撑件；
    扬声器，与所述支撑件物理连接，在所述声学设备被佩戴于用户头部时所述扬声器与所述用户的耳膜之间形成开放空间；
    第二声音传感器模组，与所述支撑件物理连接，被配置为采集第二声音并生成第二声音信号，其中，所述扬声器到所述第二声音传感器模组的传递函数与所述扬声器到所述耳膜的传递函数之间满足第一预设关系，且所述第一预设关系独立于所述声学设备的位姿；以及
    降噪电路，被配置为：
    从所述第二声音传感器模组获取所述第二声音信号，
    基于所述第二声音信号和所述第一预设关系，对所述降噪电路的降噪参数进行调整，以及
    基于所述调整后的降噪参数进行主动降噪。
  2. 根据权利要求1所述的声学设备，其特征在于，
    所述声学设备还包括第一声音传感器模组，与所述支撑件物理连接，被配置为采集第一声音并生成第一声音信号，其中，所述第一声音信号包括来自环境噪声的环境噪声信号；以及
    为了基于所述调整后的降噪参数进行主动降噪，所述降噪电路：
    从所述第一声音传感器模组获取所述第一声音信号，
    对所述第一声音信号或所述第二声音信号中的至少一个进行滤波以生成消噪信号，以及
    向所述扬声器发送所述消噪信号，以使所述扬声器将所述消噪信号转换为消噪音频以降低所述耳膜处的环境噪声的音量。
  3. 根据权利要求2所述的声学设备，其特征在于，
    所述第一声音传感器模组相对于所述扬声器远离所述耳膜；以及
    所述第二声音传感器模组相对于所述扬声器贴近所述耳膜。
  4. 根据权利要求1所述的声学设备，其特征在于，为了对所述降噪电路的降噪参数进行调整，所述降噪电路：
    对所述扬声器到所述第二声音传感器模组的传递函数进行测量得到第一传递函数；
    基于所述第一传递函数、所述第一预设关系以及所述第二声音信号，确定所述耳膜处的环境噪声；以及
    以最小化所述耳膜处的环境噪声为目标，对所述降噪电路的降噪参数进行调整。
  5. 根据权利要求4所述的声学设备，其特征在于，为了测量得到第一传递函数，所述降噪电路：
    向所述扬声器发送测试音频信号，以使所述扬声器发出对应的测试音频，所述测试音频被所述第二声音传感器模组采集到；
    获取所述第二声音传感器模组采集到的采集音频信号；以及
    根据所述测试音频信号和所述采集音频信号，确定所述第一传递函数。
  6. 根据权利要求1所述的声学设备，其特征在于，环境噪声到所述第二声音传感器模组的传递函数与所述环境噪声到所述耳膜的传递函数之间满足第二预设关系，且所述第二预设关系独立于所述声学设备的位姿；以及
    为了对所述降噪电路的降噪参数进行调整，所述降噪电路：基于所述第二声音信号、所述第一预设关系和所述第二预设关系，对所述降噪电路的降噪参数进行调整。
  7. 根据权利要求6所述的声学设备，其特征在于，为了对所述降噪电路的降噪参数进行调整，所述降噪电路：
    对所述扬声器到所述第二声音传感器模组的传递函数进行测量得到第一传递函数；
    基于所述第一传递函数、所述第一预设关系、所述第二预设关系以及所述第二声音信号，确定所述耳膜处的环境噪声；以及
    以最小化所述耳膜处的环境噪声为目标，对所述降噪电路的降噪参数进行调整。
  8. 根据权利要求1所述的声学设备，其特征在于，为了对所述降噪电路的降噪参数进行调整，所述降噪电路：
    获取所述用户在所述声学设备的多个工作模式中指示的目标工作模式，其中，在每个工作模式下所述降噪电路对应有默认降噪参数，且不同的工作模式对应的所述默认降噪参数不同；以及
    基于所述第二声音信号和所述第一预设关系，对所述目标工作模式对应的所述默认降噪参数进行调整。
  9. 根据权利要求2所述的声学设备，其特征在于，
    所述降噪电路包括下述滤波器中的至少一种：
    前馈滤波器，连接所述第一声音传感器模组和所述扬声器，并被配置为对所述第一声音信号进行滤波，或者
    反馈滤波器，连接所述第二声音传感器模组和所述扬声器，并被配置为对所述第二声音信号进行滤波；以及
    所述降噪参数包括所述前馈滤波器的滤波参数或所述反馈滤波器的滤波参数中的至少一种。
  10. 根据权利要求2所述的声学设备，其特征在于，所述降噪电路包括前馈滤波器，连接所述第一声音传感器模组和所述扬声器，并被配置为对所述第一声音信号进行滤波，所述降噪参数包括所述前馈滤波器的滤波增益；以及
    为了对所述降噪参数进行调整，所述降噪电路：
    以最小化所述第二声音信号为降噪目标，确定所述前馈滤波器所需的第一滤波增益；
    根据所述第一滤波增益和所述第一预设关系，确定在以最小化所述耳膜处的环境噪声为降噪目标时，所述前馈滤波器所需的第二滤波增益；以及
    将所述前馈滤波器的当前滤波增益调整为所述第二滤波增益。
  11. 根据权利要求1所述的声学设备，其特征在于，所述降噪电路包括：
    至少一个存储介质，存储有至少一个指令集，用于进行降噪；以及
    至少一个处理器，同所述扬声器、第二声音传感模组以及所述至少一个存储介质通信连接，
    其中，当所述声学设备运行时，所述至少一个处理器读取所述至少一个指令集，并且根据所述至少一个指令集的指示执行：
    从所述第二声音传感器模组获取所述第二声音信号，
    基于所述第二声音信号和所述第一预设关系，对所述降噪电路的降噪参数进行调整，
    基于所述调整后的降噪参数进行主动降噪。
  12. 根据权利要求1所述的声学设备，其特征在于，所述声学设备为耳机、消声器、助听器、声学眼镜中的一种。
  13. 一种主动降噪方法，其特征在于，应用于如权利要求1所述的开放式可穿戴声学设备，所述方法包括通过所述降噪电路：
    从所述第二声音传感器模组获取所述第二声音信号，
    基于所述第二声音信号和所述第一预设关系，对所述降噪电路的降噪参数进行调整，
    基于所述调整后的降噪参数进行主动降噪。
  14. 根据权利要求13所述的方法，其特征在于，所述声学设备还包括第一声音传感器模组，与所述支撑件物理连接，被配置为采集第一声音并生成第一声音信号，其中，所述第一声音信号包括来自环境噪声的环境噪声信号；以及
    基于所述调整后的降噪参数进行主动降噪，包括：
    从所述第一声音传感器模组获取所述第一声音信号，
    对所述第一声音信号或所述第二声音信号中的至少一个进行滤波以生成消噪信号，以及
    向所述扬声器发送所述消噪信号，以使所述扬声器将所述消噪信号转换为消噪音频以降低所述耳膜处的环境噪声的音量。
  15. 根据权利要求13所述的方法，其特征在于，所述基于所述第二声音信号和所述第一预设关系，对所述降噪电路的降噪参数进行调整，包括：
    对所述扬声器到所述第二声音传感器模组的传递函数进行测量得到第一传递函数；
    基于所述第一传递函数、所述第一预设关系以及所述第二声音信号，确定所述耳膜处的环境噪声；以及
    以最小化所述耳膜处的环境噪声为目标，对所述降噪电路的降噪参数进行调整。
  16. 根据权利要求13所述的方法，其特征在于，对所述扬声器到所述第二声音传感器模组的传递函数进行测量得到第一传递函数，包括：
    向所述扬声器发送测试音频信号，以使所述扬声器发出对应的测试音频，所述测试音频被所述第二声音传感器模组采集到；
    获取所述第二声音传感器模组采集到的采集音频信号；以及
    根据所述测试音频信号和所述采集音频信号，确定所述第一传递函数。
  17. 根据权利要求13所述的方法，其特征在于，环境噪声到所述第二声音传感器模组的传递函数与所述环境噪声到所述耳膜的传递函数之间满足第二预设关系，且所述第二预设关系独立于所述声学设备的位姿；以及
    所述基于所述第二声音信号和所述第一预设关系，对所述降噪电路的降噪参数进行调整，包括：基于所述第二声音信号、所述第一预设关系和所述第二预设关系，对所述降噪电路的降噪参数进行调整。
  18. 根据权利要求17所述的方法，其特征在于，所述基于所述第二声音信号、所述第一预设关系和所述第二预设关系，对所述降噪电路的降噪参数进行调整，包括：
    对所述扬声器到所述第二声音传感器模组的传递函数进行测量得到第一传递函数；
    基于所述第一传递函数、所述第一预设关系、所述第二预设关系以及所述第二声音信号，确定所述耳膜处的环境噪声；以及
    以最小化所述耳膜处的环境噪声为目标，对所述降噪电路的降噪参数进行调整。
  19. 根据权利要求13所述的方法，其特征在于，所述基于所述第二声音信号和所述第一预设关系，对所述降噪电路的降噪参数进行调整，包括：
    获取所述用户在所述声学设备的多个工作模式中指示的目标工作模式，其中，在每个工作模式下所述降噪电路对应有默认降噪参数，且不同的工作模式对应的所述默认降噪参数不同；以及
    基于所述第二声音信号和所述第一预设关系，对所述目标工作模式对应的所述默认降噪参数进行调整。
  20. 根据权利要求14所述的方法，其特征在于，
    所述降噪电路包括下述滤波器中的至少一种：
    前馈滤波器，连接所述第一声音传感器模组和所述扬声器，并被配置为对所述第一声音信号进行滤波，或者
    反馈滤波器，连接所述第二声音传感器模组和所述扬声器，并被配置为对所述第二声音信号进行滤波；以及
    所述降噪参数包括所述前馈滤波器的滤波参数或所述反馈滤波器的滤波参数中的至少一种。
  21. 根据权利要求14所述的方法，其特征在于，所述降噪电路包括前馈滤波器，连接所述第一声音传感器模组和所述扬声器，并被配置为对所述第一声音信号进行滤波，所述降噪参数包括所述前馈滤波器的滤波增益；以及
    所述基于所述第二声音信号和所述第一预设关系，对所述降噪电路的降噪参数进行调整，包括：
    以最小化所述第二声音信号为降噪目标，确定所述前馈滤波器所需的第一滤波增益；
    根据所述第一滤波增益和所述第一预设关系，确定在以最小化所述耳膜处的环境噪声为降噪目标时，所述前馈滤波器所需的第二滤波增益；以及
    将所述前馈滤波器的当前滤波增益调整为所述第二滤波增益。
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CN110996215A (zh) * 2020-02-26 2020-04-10 恒玄科技(北京)有限公司 确定耳机降噪参数的方法、装置以及计算机可读介质
CN113574593A (zh) * 2018-10-23 2021-10-29 Ams传感器英国有限公司 调谐方法、制造方法、计算机可读存储介质和调谐系统
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CN113574593A (zh) * 2018-10-23 2021-10-29 Ams传感器英国有限公司 调谐方法、制造方法、计算机可读存储介质和调谐系统
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