CN114467311A

CN114467311A - Active noise reduction method and device

Info

Publication number: CN114467311A
Application number: CN202080006822.4A
Authority: CN
Inventors: 张立斌; 袁庭球
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-07-24
Filing date: 2020-07-24
Publication date: 2022-05-10
Also published as: WO2022016511A1

Abstract

A method and earphone for active noise reduction, the method includes collecting sound wave vibration signal inside human ear (S610); obtaining an active noise reduction error signal according to the sound wave vibration signal inside the human ear (S620); determining a noise reduction signal according to the actively noise-reduced error signal, wherein the noise reduction signal is used for offsetting the noise signal (S630); the noise reduction signal is played to the human ear (S640). The active noise reduction error signal is determined according to the sound wave vibration signal inside the human ear, so that the quiet zone is located inside the human ear, the quiet zone can cover the eardrum to a certain extent, and therefore the active noise reduction error signal can represent the real noise reduction effect of human ear perception, and the active noise reduction effect can be enhanced.

Description

Active noise reduction method and device

Technical Field

The present application relates to the field of active noise reduction, and in particular, to a method and an apparatus for active noise reduction.

Background

Active Noise Cancellation (ANC) is based on the principle of sound wave superposition, and noise removal is realized by mutual cancellation of sound waves. The active noise reduction system includes a feedforward type and a feedback type. The feedback type active noise reduction system achieves the purpose of noise reduction through a feedback mode, specifically, an error sensor is used for collecting an error signal obtained by superposing a noise reduction signal and a noise signal, and a more accurate noise reduction signal is generated according to the error signal.

In the existing feedback type active noise reduction earphone, the error sensor is usually located at the external ear canal opening, and the problem that the error signal collected by the error sensor cannot well represent the real noise reduction effect sensed by human ears can exist, so that the collected error signal is not accurate enough, and the active noise reduction effect is influenced.

Disclosure of Invention

The application provides a method and a device for active noise reduction, which can enable an error signal in a feedback type active noise reduction system to better represent the real noise reduction effect of human ear perception by acquiring the error signal according to a sound wave vibration signal inside an ear, thereby enhancing the active noise reduction effect.

In a first aspect, a method for active noise reduction is provided, the method comprising: collecting sound wave vibration signals inside human ears;

obtaining an active noise reduction error signal according to the sound wave vibration signal inside the human ear; determining a noise reduction signal according to the active noise reduction error signal, wherein the noise reduction signal is used for offsetting a noise signal; and playing the noise reduction signal to human ears.

In the existing active noise reduction system, a quiet zone is positioned at the external auditory meatus, so that the situation that the quiet zone cannot cover eardrum can easily occur. It is understood that the eardrum is the organ that collects sound, and sound waves cause the eardrum to vibrate, and information about the vibration of the eardrum is transmitted to the brain, so that a person perceives the sound. I.e. the position of the eardrum is the auditory perception position. If the ear drum is not covered by the quiet zone, the acquired error signal may not represent the active noise reduction effect at the ear drum, that is, the real noise reduction effect perceived by the human ear, so that the active noise reduction effect is reduced.

In this application, through the sound wave vibration signal according to the inside ear of a person confirming the error signal of making an uproar actively for the quiet area is located the ear of a person inside, for prior art, has drawn close the distance of quiet area to eardrum, can make the quiet area cover the eardrum to a certain extent, consequently, can make the error signal of making an uproar actively fall more can represent the real noise reduction effect of the perception of the ear of a person, thereby can strengthen the effect of making an uproar actively fall.

With reference to the first aspect, in a possible implementation manner, the acquiring a sound wave vibration signal inside a human ear includes: collecting sound wave vibration signals at the eardrum.

The active noise reduction error signal is determined based on the sound wave vibration signal at the eardrum, which is equivalent to a dead zone formed at the eardrum, so that the dead zone can cover the eardrum, therefore, the active noise reduction error signal can accurately represent the real noise reduction effect of human ear perception, and the active noise reduction effect can be improved.

With reference to the first aspect, in one possible implementation manner, the acquiring a sonic vibration signal at an eardrum includes: emitting light towards the eardrum; receiving light reflected by the eardrum; and obtaining a sound wave vibration signal at the eardrum according to the light reflected by the eardrum.

In the application, the error signal of active noise reduction is determined based on the sound wave vibration signal at the eardrum, which is equivalent to a dead zone formed at the eardrum, so that the error signal of active noise reduction accurately represents the real noise reduction effect perceived by human ears, and thus the effect of active noise reduction can be further improved.

In addition, according to the present application, since a dead zone can be formed at the eardrum, an active noise reduction effect can be enhanced for both low frequency sound signals and high frequency sound signals.

With reference to the first aspect, in a possible implementation manner, the acquiring a sound wave vibration signal inside a human ear includes: collecting a sound wave vibration signal in the external auditory canal space.

The determination of the actively noise-reduced error signal based on the acoustic vibration signal in the external auditory canal space corresponds to the formation of a dead space in the external auditory canal space. Compared with the prior art, the distance from the quiet zone to the eardrum is shortened, the quiet zone can cover the eardrum to a certain extent, and therefore the error signal of active noise reduction can represent the real noise reduction effect of human ear perception, and the active noise reduction effect can be enhanced.

With reference to the first aspect, in a possible implementation manner, the acquiring a sound wave vibration signal inside a human ear further includes: collecting sound wave vibration signals in the external auditory canal space; wherein, the error signal of actively making an uproar falls according to the inside sound wave vibration signal of people's ear includes: obtaining a first error signal according to the sound wave vibration signal at the eardrum; obtaining a second error signal according to the sound wave vibration signal in the external auditory canal space; and obtaining the active noise reduction error signal according to the first error signal and the second error signal.

Optionally, the obtaining the active noise reduction error signal according to the first error signal and the second error signal includes: and carrying out weighted addition on the first error signal and the second error signal to obtain an error signal for active noise reduction.

Optionally, the obtaining the active noise reduction error signal according to the first error signal and the second error signal includes: and averaging the first error signal and the second error signal to obtain an active noise reduction error signal.

It should be understood that the first error signal and the second error signal may be subjected to other comprehensive processing according to application requirements, so as to obtain an error signal for active noise reduction.

In this application, the sound wave vibration signal according to eardrum department and the sound wave vibration signal in the external auditory canal space acquire the error signal of initiatively making an uproar, can be so that the initiative error signal who acquires is more comprehensive, more accurate to can make this error signal represent the real noise reduction effect of people's ear perception better, consequently can further improve error signal's accuracy, thereby strengthen the effect of initiatively making an uproar better.

It should be understood that the present application can realize active noise reduction with higher frequency, and also can realize more stable active noise reduction effect.

With reference to the first aspect, in one possible implementation manner, the acquiring a sonic vibration signal in an external auditory canal space includes: collecting a sonic vibration signal in the external ear canal space using a vibration sensor disposed on an ear plug.

With reference to the first aspect, in one possible implementation manner, the vibration sensor disposed on the ear plug includes a sonic vibration collection unit disposed on a plurality of positions of the ear plug.

Therefore, in the application, the active noise reduction error signals are obtained according to the sound wave vibration signals at a plurality of positions in the external auditory canal space, the range of a quiet area can be enlarged, the active noise reduction error signals can be close to the real noise reduction effect of human ear perception, and the active noise reduction effect can be enhanced.

In one possible implementation form, in combination with the first aspect, the vibration sensor disposed on the ear plug is a thin film microphone disposed on the ear plug in a ring shape.

It should be understood that in the present application, the way of collecting the acoustic vibration signal inside the human ear may be any of the following ways:

1) collecting only sound wave vibration signals at the eardrum;

2) collecting only sound wave vibration signals in the external auditory canal space;

3) the sound wave vibration signals at the eardrum position are collected, and the sound wave vibration signals in the external auditory canal space are collected.

With reference to the first aspect, in a possible implementation manner, the method further includes: collecting sound wave vibration signals of an external auditory meatus; wherein, the error signal of actively making an uproar falls according to the inside sound wave vibration signal of people's ear includes: and obtaining the active noise reduction error signal according to the sound wave vibration signal inside the human ear and the sound wave vibration signal at the external ear canal opening.

The active noise reduction error signal is acquired according to the sound wave vibration signals acquired at multiple positions of the ears, so that the dead zone is larger, the active noise reduction error signal is more comprehensive and accurate, and the active noise reduction effect can be improved.

In a second aspect, there is provided an active noise reduction headphone, comprising: the error sensor is used for acquiring sound wave vibration signals inside human ears and obtaining active noise reduction error signals according to the sound wave vibration signals; the controller is used for determining a noise reduction signal according to the active noise reduction error signal obtained by the error sensor, and the noise reduction signal is used for offsetting a noise signal; and the loudspeaker is used for playing the noise reduction signal determined by the controller to human ears.

With reference to the second aspect, in a possible implementation manner, the error sensor includes a first acoustic vibration sensor for acquiring an acoustic vibration signal at the eardrum.

With reference to the second aspect, in one possible implementation manner, the first acoustic wave vibration sensor is configured to: emitting light toward the eardrum; receiving light reflected by the eardrum; and obtaining a sound wave vibration signal at the eardrum according to the light reflected by the eardrum.

With reference to the second aspect, in one possible implementation, the headset includes an ear plug, and the error sensor includes a second acoustic vibration sensor disposed on the ear plug for collecting an acoustic vibration signal in the external auditory canal space.

With reference to the second aspect, in one possible implementation, the earphone includes an ear plug, and the error sensor includes a second acoustic vibration sensor disposed on the ear plug for acquiring an acoustic vibration signal in an external auditory canal space; the error sensor further comprises a processing unit, and the processing unit is used for acquiring the active noise reduction error signal according to the sound wave vibration signal acquired by the first sound wave vibration sensor and the sound wave vibration signal acquired by the second sound wave vibration sensor in the space of the external auditory canal.

With reference to the second aspect, in one possible implementation, the second acoustic vibration sensor includes an acoustic vibration pickup unit disposed at a plurality of locations of the ear plug.

With reference to the second aspect, in one possible implementation manner, the second acoustic vibration sensor is a film microphone annularly disposed on the ear plug.

With reference to the second aspect, in a possible implementation manner, the error sensor is further configured to collect a sound wave vibration signal of the external ear canal orifice, and obtain the active noise reduction error signal according to the sound wave vibration signal inside the human ear and the sound wave vibration signal of the external ear canal orifice.

Alternatively, in the active noise reduction earphone provided in the second aspect, the operation of obtaining the active noise reduction error signal according to the collected sound wave vibration signal inside the human ear may be performed by an error sensor, or may be performed by another processing unit, where the other processing unit may be directly the controller, or may be another processing unit inside the earphone. For example, the earphone further comprises an intermediate processing unit for obtaining an active noise reduction error signal from the acoustic vibration signal.

It should be noted that, in practical applications, which unit or module inside the earphone performs the operation of obtaining the active noise reduction error signal according to the collected sound wave vibration signal inside the human ear may depend on the design principle of the error sensor inside the earphone.

For example, the error sensor may be configured to collect the sonic vibration signal and directly output the collected signal without further processing of the sonic vibration signal. In this case, the operation of obtaining an error signal for active noise reduction from the acoustic vibration signal may be performed by other units or modules inside the headset.

For another example, the error sensor may be configured to collect the sonic vibration signal and output a further processed signal (error signal), i.e. the error sensor is also configured to obtain an actively noise-reduced error signal from the sonic vibration signal. In this case, the operation of obtaining the error signal for active noise reduction from the acoustic vibration signal may be performed by the error sensor.

Alternatively, in the active noise reduction headphone provided in the second aspect, the controller may be a hardware circuit. For example, the controller may be an adaptive filter, for example.

Based on the above description, in this application, through the sound wave vibration signal according to the inside human ear determine the error signal of initiatively making an uproar for the quiet area is located inside the human ear, for prior art, has drawn close the distance of quiet area to eardrum, can make the quiet area cover the eardrum to a certain extent, consequently, can make the error signal of initiatively making an uproar more can represent the real noise reduction effect of human ear perception, thereby can strengthen the effect of initiatively making an uproar.

Drawings

FIG. 1 is a schematic block diagram of an active noise reduction system.

Fig. 2 is a schematic diagram of an active noise reduction system.

Fig. 3 is a schematic diagram of superposition cancellation of a noise reduction signal and a noise signal.

Fig. 4 is a schematic view of a headphone configuration of the active noise reduction system shown in fig. 1.

Fig. 5 is a schematic diagram of a prior art active noise reduction system forming a dead zone.

Fig. 6 is a schematic flowchart of a method for active noise reduction according to an embodiment of the present application.

Fig. 7 is another schematic flow chart of a method for active noise reduction according to an embodiment of the present application.

Fig. 8 and 9 are schematic diagrams illustrating the principle of optical detection of acoustic vibrations.

Fig. 10 is a further schematic flowchart of a method for active noise reduction according to an embodiment of the present application.

Fig. 11 is a further schematic flowchart of a method for active noise reduction according to an embodiment of the present application.

Fig. 12 is a schematic flowchart of an active noise reduction headphone according to an embodiment of the present application.

Fig. 13 is a schematic product form diagram of an active noise reduction earphone according to an embodiment of the present application.

Fig. 14 and 15 are schematic views of the earphone shown in fig. 13 in a use state.

Fig. 16 is a schematic diagram of another product form of the active noise reduction earphone according to the embodiment of the present application.

Fig. 17 and 16 are schematic views of the earphone in use.

Fig. 18 is a schematic block diagram of an error sensor in an active noise reduction earphone according to an embodiment of the present application.

Fig. 19 is a schematic diagram of another product form of the active noise reduction earphone according to the embodiment of the present application.

Fig. 20 is a further schematic block diagram of an error sensor in an active noise reduction earphone according to an embodiment of the present application.

Fig. 21 is a further schematic block diagram of an error sensor in an active noise reduction earphone according to an embodiment of the present application.

Detailed Description

Active Noise Cancellation (ANC) is a technique for removing noise by canceling sound waves based on the principle of sound wave superposition. Active noise reduction systems include both feedforward and feedback types, and the present application is directed to feedback-type active noise reduction systems only. Unless otherwise specified, the active noise reduction referred to in the embodiments of the present application refers to a feedback type active noise reduction.

As an example, the composition and noise reduction principle of the feedback type active noise reduction system will be described with reference to fig. 1, fig. 2, fig. 3 and fig. 4.

As shown in fig. 1, an active noise reduction system generally includes a controller 110, a speaker (spaker) 120, an error sensor (error mic)130, and a reference sensor (ref mic) 140.

Referring to fig. 2, the working principle and the working flow of the active noise reduction system shown in fig. 1 are as follows.

Firstly, the error sensor 130 collects the error signals e (n) and transmits the error signals e (n) to the controller 110.

The error signal e (n) represents sound field characteristics in the quiet zone shown in fig. 2, including characteristics such as sound pressure and particle velocities in different directions, for example. The concept of dead zones will be described below and will not be described in detail here.

The error sensor 130 is typically an acoustic sensor. As shown in fig. 2, 3 and 4, the error sensor 130 is a microphone.

Step two, the reference sensor 140 collects the noise signal x (n) and transmits the noise signal x (n) to the controller 110.

It should be understood that the noise signal x (n) collected by the reference sensor 140 is an ambient noise signal. The ambient noise signal is typically emitted by an undesired noise source, as shown in fig. 2.

The reference sensor 140 is typically an acoustic sensor. As shown in fig. 2, 3 and 4, the reference sensor 140 is a microphone.

Step three, the controller 110 calculates an error cost function based on the error signal e (n), and predicts a noise reduction signal y (n) output by the speaker 120 based on the noise signal x (n) based on the error cost function minimization principle.

The noise reduction signal y (n) is used to cancel the noise signal x (n). Ideally, the noise reduction signal y (n) is an inverse of the noise signal x (n). The noise reduction signal y (n) may also be referred to as the anti-noise signal.

For example, the controller 110 may be an adaptive filter.

In the fourth step, the speaker 120 sends out the noise reduction signal y (n) according to the control of the controller 110.

As shown in fig. 2, the noise signal x (n) and the noise reduction signal y (n) reach the quiet zone through the primary path and the secondary path, respectively.

As shown in fig. 3, the error sensor 130 collects a sound signal obtained by superimposing the noise signal x (n) and the noise reduction signal y (n) after passing through the primary path and the secondary path, respectively, and reaching the quiet zone, and the sound signal is referred to as an error signal e (n). The noise signal e (n) collected by the error sensor 130 can also be described as residual noise after the noise reduction process.

The goal of the controller 110 to predict the noise reduction signal y (n) output by the speaker 120 is to minimize the error cost function of the noise signal x (n) and the noise reduction signal y (n) after they reach the dead zone via the primary path and the secondary path, respectively, and then are superimposed on each other.

For example, if the noise source is considered a primary sound source, the speaker 120 may be referred to as a secondary sound source, as shown in fig. 2.

Typically, the product form of the active noise reduction system is a headphone, as shown in fig. 4 by way of example. A reference sensor 140 is provided on the earphone housing for collecting ambient noise signals. The error sensor 130 is disposed in the earphone housing and is used for collecting an error signal after noise reduction processing. The controller 110 is disposed within the earphone housing for predicting a noise reduction signal output by the speaker 120 based on the noise signal and the error signal. The speaker 120 is disposed within the earphone housing and plays the noise reduction signal predicted by the controller 110. The active input sound signal shown in fig. 4 represents a signal that the user wants to play, for example, music or a call signal.

It should be understood that in the earphone play scenario as shown in fig. 4, the sound signal arriving at the human ear has a valid sound signal, such as music or a conversation, in addition to the ambient noise signal and the noise reduction signal. In the earphone playing scene, in the process of acquiring the error signal, the effective sound signal can be eliminated. For example, by means of signal processing, the effective sound signal is removed, and residual noise after active noise reduction, i.e. an error signal, is obtained. It is prior art to reject valid audio signals when obtaining error signals, which is not described in detail herein.

Fig. 2-4 are exemplary only and not limiting. For example, the primary channel and the secondary channel shown in fig. 2 are only for distinguishing the propagation paths of the noise signal x (n) and the noise reduction signal y (n), and do not represent that the primary channel and the secondary channel are physically present in the active noise reduction system.

It should be understood that the effect of the superposition of the noise signal and the noise reduction signal at different locations is not necessarily the same. It is assumed that the error sensor collects an error signal at point a, which may characterize the effect of the noise signal on the noise reduction signal at point a, but may not necessarily characterize the effect of the noise signal on the noise reduction signal at a location other than point a. In order to express which region the error signal of the active noise reduction represents the active noise reduction effect, a concept of a dead zone (quiet zone) is proposed, which indicates a region or a space where the error signal acquired by the error sensor is located. That is, where the error sensor collects the signal, where is the dead band. For example, in fig. 2, the dead zone indicates an area where the error signal e (n) acquired by the error sensor 130 is located.

It should also be appreciated that the goal of the controller 110 to predict the noise reduction signal y (n) output by the speaker 120 is to minimize the error cost function of the noise reduction signal y (n) and the noise signal x (n) after they reach the dead band, respectively, and then add up to the signal e (n). That is, the active noise reduction system aims to achieve an active noise reduction effect in the dead zone.

In the existing active noise reduction system, the error sensor is an acoustic sensor (e.g., a microphone), and therefore, a position where the error sensor collects a signal is a position where the error sensor is located, that is, a position where the error sensor is located is a position of a dead zone. In existing active noise reduction systems, the error sensor is located at the meatus auricle of the human ear, as shown in fig. 5, and thus the quiet zone is located at the meatus auricle.

In the case of an active noise reduction system having only one secondary sound source (an active noise reduction system typically provides only one secondary sound source), the size of the quiet zone is related to the frequency (i.e., wavelength intensity) of the audio signal (i.e., the sound wave signal). For example, the diameters of the quiet zones of the acoustic signal at different frequencies are respectively:

a 500Hz sonic signal, a quiet zone of about 7 centimeters (cm) in diameter;

a 5000Hz sonic signal, a quiet zone of about 0.7cm in diameter;

10000Hz, the diameter of the dead zone is about 0.34 cm.

For example, for a 500Hz sound wave signal, an actively noise-reduced error signal collected at a certain point may characterize the active noise reduction effect in a region with a diameter of 7cm at the point. For another example, for a sound wave signal of 10000Hz, an error signal of active noise reduction collected at a certain point can represent the active noise reduction effect in a region with a diameter of 0.34cm where the point is located.

With continued reference to fig. 5. The low-frequency quiet zone in fig. 5 represents a quiet zone corresponding to a lower-frequency acoustic signal, for example, a quiet zone corresponding to an acoustic signal of 500Hz (a quiet zone having a diameter of about 7 cm). The high-frequency quiet zone in fig. 5 indicates a quiet zone corresponding to a sound wave signal of a higher frequency, for example, a quiet zone corresponding to a sound wave signal of 10000Hz (a quiet zone having a diameter of about 0.34 cm).

From the above description regarding the size of the quiet zone in relation to the frequency of the acoustic wave signal, and fig. 5, it can be seen that the diameter of the high frequency quiet zone is smaller than the diameter of the low frequency quiet zone, i.e. the range size of the high frequency quiet zone is smaller than the range size of the low frequency quiet zone.

As described above, in the conventional active noise reduction system, the dead zone is located at the external ear canal opening, and it is easy to cause the situation that the dead zone cannot cover the eardrum. As shown in fig. 5, the high frequency quiet zone does not cover the eardrum.

It is understood that the eardrum is the organ that collects sound, and sound waves cause the eardrum to vibrate, and information about the vibration of the eardrum is transmitted to the brain, so that a person perceives the sound. I.e. the position of the eardrum is the auditory perception position.

If the ear drum is not covered by the quiet zone, the acquired error signal may not represent the active noise reduction effect at the ear drum, that is, the real noise reduction effect perceived by the human ear, so that the active noise reduction effect is reduced. For example, existing active noise reduction systems do not have good active noise reduction effects at least for high frequency sound signals.

In view of the above technical problems, an embodiment of the present application provides an active noise reduction scheme, which obtains an active noise reduction error signal according to a sound wave vibration signal inside an ear, so that the error signal can represent a real noise reduction effect perceived by the ear, and thus, the active noise reduction effect can be enhanced.

The technical solution in the present application will be described below with reference to the accompanying drawings.

Fig. 6 is a schematic flow chart of a method 600 for active noise reduction according to an embodiment of the present application. For example, the execution subject of the method 600 is a headset. The method 600 includes steps S610, S620, S630 and S640.

S610, collecting sound wave vibration signals inside human ears.

The acoustic vibration signal inside the human ear represents a vibration signal caused by acoustic waves inside the human ear. That is, the acoustic vibration signal inside the human ear characterizes information of the acoustic waves that reach the inside of the human ear.

As shown in fig. 5, the inner structure of the human ear includes the external auditory canal and the eardrum. Inside the human ear means in the external auditory canal space and not just the external meatus. In step S620, the collected acoustic vibration signal inside the human ear may include an acoustic vibration signal in the external auditory canal space, and/or an acoustic vibration signal at the eardrum.

The acoustic vibration signal in the external auditory canal space characterizes that sound waves arriving inside the human ear cause vibration of the air in the external auditory canal space.

The acoustic vibration signal at the eardrum indicates that sound waves arriving inside the human ear cause the eardrum to vibrate.

And S620, obtaining an active noise reduction error signal according to the sound wave vibration signal in the human ear.

The actively noise-reduced error signal represents the sound signal after active noise reduction processing (i.e., the noise reduction signal is superimposed with the ambient noise signal). The actively denoised error signal may also be described as a residual signal after active denoising. The error signal represents the active noise reduction effect of the quiet zone.

The acoustic vibration signal inside the human ear represents a vibration signal caused by sound waves arriving inside the human ear, which vibration signal characterizes the information of the sound waves. That is, the acquired acoustic vibration signals inside the human ear characterize the information of the acoustic waves arriving inside the human ear.

For example, an error signal for active noise reduction can be obtained from a sound wave vibration signal inside a human ear by means of direct mapping.

It should be understood that other ways may also be adopted, and the error signal for active noise reduction may be obtained according to the sound wave vibration signal inside the human ear, which is not limited in this application embodiment as long as the finally obtained error signal may represent the noise reduction effect of the dead zone after active noise reduction.

S630, determining a noise reduction signal according to the active noise reduction error signal.

The process of determining the noise reduction signal according to the active noise reduction error signal is similar to the process of obtaining the noise reduction signal y (n) according to the error signal e (n) in fig. 2, and this process is prior art and will not be described in detail in this application.

And S640, playing the noise reduction signal to human ears.

For example, the method 600 provided by the embodiment of the present application is executed by a feedback active noise reduction earphone, steps S610 and S620 may be executed by an error sensor in the earphone, step S630 may be executed by a controller in the earphone, and step S640 may be executed by a speaker in the earphone.

As described above, in the conventional active noise reduction system, the dead zone is located at the external ear canal opening, and it is easy to cause the situation that the dead zone cannot cover the eardrum.

In this application embodiment, through the sound wave vibration signal according to the inside ear of a person confirming the error signal of making an uproar actively for the quiet area is located the ear of a person inside, for prior art, has drawn close the distance of quiet area to eardrum, can make to a certain extent the quiet area cover the eardrum, consequently, can make the error signal of making an uproar actively fall more can represent the real noise reduction effect of the perception of the ear of a person, thereby can strengthen the effect of making an uproar actively fall.

Alternatively, as shown in fig. 7, step S610 includes: collecting sound wave vibration signals at the eardrum; accordingly, in step S620, an error signal for active noise reduction is obtained from the acoustic vibration signal at the eardrum.

For example, an actively noise-reduced error signal can be obtained from the acoustic vibration signal at the eardrum by means of direct mapping.

It should be understood that other ways may also be adopted, and the error signal for active noise reduction may be obtained according to the sound wave vibration signal at the eardrum, which is not limited in this application embodiment as long as the finally obtained error signal may represent the noise reduction effect of the dead zone after active noise reduction.

The manner in which the sonic vibration signal at the eardrum is collected may be various.

Alternatively, the principle of photo-detecting sonic vibrations can be used to collect a sonic vibration signal at the eardrum.

For example, step S610 includes: emitting light towards the eardrum; receiving light reflected by the eardrum; and obtaining a sound wave vibration signal at the eardrum according to the light reflected by the eardrum.

For a better understanding of the present embodiment, the principle of the optical detection of the vibration of the acoustic wave is exemplarily described below with reference to fig. 8 and 9.

Fig. 8 is a schematic diagram of a photo-detection acoustic vibration system. The optical detection sound wave vibration system comprises an optical emitter, an optical reflector, an optical receiver and a photoelectric converter. The light reflector is an object which is easy to vibrate under the action of sound pressure around a detection target. The light emitter emits light onto the light reflector. The optical receiver detects light reflected back from the optical reflector. Because the light reflector is modulated by the vibration generated by the sound pressure, the light reflected back by the light reflector carries the sound wave information. The photoelectric converter can obtain acoustic information by demodulating the light reflected back by the light reflector.

The principle of vibration pickup is also the same as that of replacing the light reflector in fig. 8 with an eardrum. The light emitter emits light onto the eardrum. The light receiver detects light reflected back from the eardrum. The eardrum modulates the light by the vibrations generated by the sound pressure, so that the light reflected back by the light reflector carries the acoustic information. The photoelectric transducer can obtain the sound wave vibration signal of the eardrum by demodulating the light reflected back by the light reflector. Specifically, the vibration of the eardrum causes the light to be deflected to different degrees, the size of the light spot formed on the photoelectric converter is different, the size of the light spot forms a current, and the size of the current is in a linear relation with the sound wave vibration. Therefore, the current information obtained by the photoelectric converter is the sound wave vibration signal at the eardrum.

Fig. 9 is a schematic diagram of a prior art laser detection sound system. In fig. 9, the vibrator is glass.

Suppose that the sound wave vibration is L (t), the sound pressure at a certain particle of the film medium (i.e. glass) is P (x, y), the sound pressure translation of the glass is X (t), the translation of the reflected light is Y (t), the light spot area on the photosensitive surface of the detector is S (t), and the output current of the detector is I (t).

The sound pressure of the sound wave at the point of incidence is:

P(x,y,t)＝k ₁L(t)

wherein k is₁Is a constant coefficient related to the acoustic transmission distance and the air environment. The motion of the surface of the medium is proportional to the sound pressure acting at this point, in which case the medium will translate. And if the frequencies of the sounds differ in intensity, the degree of vibration caused also differs.

The sound pressure translation of the glass is as follows:

X(t)＝k ₂P(x,y,t)

wherein k is₂Is a constant coefficient related to the medium. When the medium is subjected to translational vibration, the incident angle is unchanged, but the incident point is translated along with the medium, so that the reflected light is also translated.

The translation of the reflected light is:

Y(t)＝2X(t)sinθ

where sin θ is a constant.

The instantaneous change of the light spot area on the photosensitive surface of the photoelectric detector is S (t) ═ k₃Y (t), the output current of the detector is I (t) ═ k₄S (t), wherein k₄Is a constant related to the parameters of the detector itself.

To sum up, the detector output current is:

I(t)＝2k ₁k ₂k ₃k ₄L(t)sinθ

in the above formula, k₁、k ₂、k ₃、k ₄And sin theta are constants, the output current of the detector and the sound wave vibration are in a linear relation, namely, the sound signals are collected by recording electric signals.

The glass in fig. 9 is replaced by an eardrum, and the principle of vibration pickup is also the same. When the principle shown in fig. 9 is applied to the present embodiment for collecting the acoustic vibration signal at the eardrum, the light emitted toward the eardrum may be infrared (wavelength of 800 nanometers (nm)) or other low-wavelength light. For example, infrared light is emitted to the eardrum at an emission intensity of not higher than 0.01 milliwatts (mw).

It should be noted that, as the future technology evolves, other feasible ways may also be adopted to collect the sound wave vibration signal at the eardrum. The scheme of obtaining the active noise reduction error signal according to the sound wave vibration signal at the eardrum falls into the protection scope of the present application.

In this embodiment, the active noise reduction error signal is determined based on the sound wave vibration signal at the eardrum, which is equivalent to a dead zone formed at the eardrum, so that the active noise reduction error signal can accurately represent the real noise reduction effect perceived by the human ear, and thus the active noise reduction effect can be further improved.

In addition, according to the present embodiment, since a dead zone can be formed at the eardrum, the active noise reduction effect can be enhanced for both low-frequency sound signals and high-frequency sound signals.

Alternatively, as shown in fig. 10, step S610 includes: collecting sound wave vibration signals in the external auditory canal space; accordingly, in step S620, an error signal for active noise reduction is obtained from the acoustic wave vibration signal in the external auditory canal space.

For example, an actively noise-reduced error signal can be obtained from the acoustic vibration signal in the external auditory canal space by means of direct mapping.

It should be understood that other ways may also be adopted to obtain the active noise reduction error signal according to the sound wave vibration signal in the external auditory canal space, which is not limited in the embodiment of the present application as long as the finally obtained error signal can represent the noise reduction effect of the dead zone after active noise reduction.

For example, a sonic vibration signal in the external ear canal space may be collected using a vibration sensor disposed on the ear plug.

It will be appreciated that the earplug is located in the external auditory canal in a state of use, and therefore, the vibration sensor disposed on the earplug can pick up a sound vibration signal in the external auditory canal space.

For example, the vibration sensor disposed on the ear bud may be a thin film microphone. The principle of a membrane microphone is the piezoelectric principle. The principle of the membrane microphone for collecting the acoustic vibration signal is prior art and will not be described in detail herein.

Alternatively, in step S610, acoustic vibration signals at a plurality of points in the external auditory canal space are collected.

For example, a vibroacoustic signal in the external auditory canal space can be collected using vibroacoustic collection units disposed at multiple locations on the ear plugs. For example, a membrane microphone annularly disposed on an earplug is used to collect a sonic vibration signal in the external auditory canal space.

It will be appreciated that the acoustic vibration signal at multiple locations in the external auditory canal space may be indicative of information of acoustic waves arriving at multiple locations in the external auditory canal space. The actively noise-reduced error signal obtained from the acoustic vibration signal at multiple locations in the external auditory canal space represents the acoustic signal energy in a larger space within the external auditory canal space.

In the existing active noise reduction system, the error sensor collects the error signal as a single point, as shown in fig. 5.

Compared with the prior art, the embodiment can be regarded as extending the single-point error signal acquisition to the error signal acquisition of more spatial positions, that is, forming a wider range of dead zones. Because the range of the quiet zone is enlarged, the quiet zone can be ensured to cover the eardrum to a greater extent, so that the error signal of active noise reduction can better represent the real noise reduction effect of human ear perception, and the active noise reduction effect is enhanced.

Therefore, in this embodiment, the active noise reduction error signals are obtained according to the sound wave vibration signals at a plurality of positions in the external auditory canal space, so that the range of the quiet zone can be enlarged, the active noise reduction error signals can be closer to the real noise reduction effect perceived by human ears, and the active noise reduction effect can be enhanced.

It should be understood that as technology evolves, other feasible methods of collecting the sonic vibration signals in the external auditory canal space may also be employed. The scheme of obtaining the active noise reduction error signal according to the sound wave vibration signal in the external auditory canal space falls into the protection scope of the present application.

Alternatively, as shown in fig. 11, step S610 includes: collecting sound wave vibration signals at the eardrum and collecting sound wave vibration signals in the space of the external auditory canal; step S620 includes steps S621, S622, and S623.

S621, a first error signal is obtained according to the acoustic vibration signal at the eardrum.

For example, an error signal can be obtained from the acoustic vibration signal at the eardrum as the first error signal by direct mapping.

And S622, obtaining a second error signal according to the sound wave vibration signal in the external auditory canal space.

For example, one error signal may be obtained from the acoustic vibration signal at the eardrum as the second error signal by means of direct mapping.

S623, obtaining an active noise reduction error signal according to the first error signal and the second error signal.

For example, the first error signal and the second error signal may be weighted and summed to obtain an actively noise-reduced error signal.

It should be understood that the first error signal and the second error signal may be processed in other manners according to application requirements to obtain an actively noise-reduced error signal.

In the embodiment of fig. 11, reference is made to the description of collecting the sonic vibration signal at the eardrum and the description of collecting the sonic vibration signal in the external auditory canal space, which are not repeated here.

Determining an error signal for active noise reduction based on the acoustic vibration signal at the eardrum and the acoustic vibration signal in the external auditory canal space corresponds to forming a quiet zone at the eardrum and in the external auditory canal space.

In this embodiment, the error signal of actively reducing noise is obtained according to the sound wave vibration signal of eardrum department and the sound wave vibration signal in the external auditory canal space, so that the obtained active error signal is more comprehensive and more accurate, thereby the error signal can represent the real noise reduction effect of human ear perception better, and therefore the accuracy of the error signal can be further improved, and the active noise reduction effect can be better enhanced.

It should be understood that the present embodiment can implement active noise reduction with higher frequency, and also can implement more stable active noise reduction effect.

As can be seen from the above description, in the embodiment of the present application, the method of collecting the acoustic vibration signal inside the human ear may be any one of the following methods 1), 2), and 3).

1) Only the acoustic vibration signal at the eardrum is acquired, as in the embodiment shown in fig. 7.

2) Only the sonic vibration signal in the external auditory canal space is collected, as in the embodiment shown in fig. 10.

3) Collecting both the acoustic vibration signal at the eardrum and the acoustic vibration signal in the external auditory canal space, as in the embodiment shown in fig. 11.

Optionally, in the embodiment shown in fig. 6, the method 600 may further include: collecting sound wave vibration signals of an external auditory meatus; wherein, step S620 includes: and obtaining an active noise reduction error signal according to the sound wave vibration signal inside the human ear and the sound wave vibration signal at the external ear canal opening.

For example, the acoustic vibration signals of the meatus of the external ear can be collected in a manner as shown in fig. 5.

Optionally, in the embodiment shown in fig. 6, the method 600 further includes acquiring a noise signal, wherein the step S630 includes: and determining a noise reduction signal according to the acquired noise signal and the error signal obtained in the step S620.

For example, assuming that the noise signal is x (n) and the error signal is e (n), the noise reduction signal can be calculated based on x (n) and e (n) by using a minimum mean square error algorithm.

The method for obtaining the noise reduction signal according to the noise signal is prior art and will not be described in detail herein.

Based on the above description, in this application embodiment, through the sound wave vibration signal according to the inside human ear determine the error signal of initiatively making an uproar for the quiet area is located inside the human ear, for prior art, has drawn close the distance of quiet area to eardrum, can make the quiet area cover the eardrum to a certain extent, consequently, can make the error signal of initiatively making an uproar more can represent the real noise reduction effect of human ear perception, thereby can strengthen the effect of initiatively making an uproar.

The active noise reduction method provided by the embodiment of the application can be applied to earphones. The earphone to which the embodiments of the present invention can be applied may have various shapes, for example, an open type, a closed type, an earcap type, an ear hook type, an earplug type, and the like.

Fig. 12 is a schematic block diagram of an active noise reduction earphone 1200 according to an embodiment of the present application. The headset 1200 includes a controller 1210, an error sensor 1220, and a speaker 1230.

And the error sensor 1220 is configured to collect a sound wave vibration signal inside a human ear, and obtain an active noise reduction error signal according to the sound wave vibration signal.

And a controller 1210 for determining a noise reduction signal according to the active noise reduction error signal obtained by the error sensor 1220, wherein the noise reduction signal is used for offsetting the noise signal.

And a speaker 1230 for playing the noise reduction signal determined by the controller 1210 to the human ear.

For example, the controller 1210 is configured to control the speaker 1230 to play the noise reduction signal when the noise signal reaches the earphone 1200.

The embodiment of the application provides an active noise reduction earphone 1200, through the sound wave vibration signal according to the inside of people's ear confirm the active noise reduction's error signal, make the quiet zone be located inside people's ear, for prior art, drawn the distance of quiet zone to eardrum, can make the quiet zone cover the eardrum to a certain extent, consequently, can make the active noise reduction's error signal more can represent the real noise reduction effect of people's ear perception, thereby can strengthen the active noise reduction's effect.

Alternatively, the operation of obtaining the active noise reduction error signal according to the collected sound wave vibration signal inside the human ear may be performed by the error sensor 1220, or may be performed by another processing unit, which may be directly the controller 1210, or may be another processing unit inside the headset 1200. For example, the headset 1200 further comprises an intermediate processing unit for obtaining an actively noise reduced error signal from the acoustic vibration signal.

For another example, the error sensor may be configured to collect the sonic vibration signal and output a further processed signal (error signal), i.e. the error sensor is also configured to obtain an actively noise-reduced error signal from the sonic vibration signal. In this case, the operation of obtaining an error signal for active noise reduction from the acoustic vibration signal may be performed by the error sensor.

In this embodiment, the error sensor is configured to collect the acoustic vibration signal, and further process the acoustic vibration signal to obtain an error signal for active noise reduction.

Optionally, the error sensor 1220 includes a first sonic vibration sensor 1221 for collecting a sonic vibration signal at the eardrum.

As shown in fig. 13, a first sonic vibration sensor 1221 is located on the earphone housing. The controller 1210 is not shown in fig. 13.

Alternatively, the first sonic vibration sensor 1221 may employ the principles shown in fig. 8 and 9 to collect a sonic vibration signal at the eardrum.

As shown in fig. 14 and 15, the first acoustic vibration sensor 1221 is configured to: emitting light to the eardrum; receiving light reflected by the eardrum; and obtaining a sound wave vibration signal at the eardrum according to the light reflected by the eardrum.

For example, the first acoustic vibration sensor 1221 includes a light emitter, a light receiver, and a photoelectric converter. The light emitter is used for emitting light to the eardrum. The light receiver is used for receiving the light reflected by the eardrum. The photoelectric converter is used for obtaining an acoustic vibration signal at the eardrum according to the light received by the light receiver.

Determining the error signal for active noise reduction based on the acoustic vibration signal at the eardrum corresponds to the formation of a dead zone at the eardrum, as shown in fig. 14.

The earphone 1200 provided by this embodiment can determine the active noise reduction error signal according to the sound wave vibration signal at the eardrum, which is equivalent to forming a dead zone at the eardrum, so that the active noise reduction error signal can accurately represent the real noise reduction effect perceived by the human ear, and thus the active noise reduction effect can be further improved.

In addition, the earphone 1200 provided by the present embodiment can enhance the active noise reduction effect for both low frequency sound signals and high frequency sound signals because a dead zone can be formed at the eardrum.

Alternatively, as shown in FIG. 16, the ear piece 1200 includes an ear plug and the error sensor 1220 includes a second sonic vibration sensor 1222 disposed on the ear plug for collecting sonic vibration signals in the external auditory canal space. The controller 1210 is not shown in fig. 16.

For example, the second acoustic vibration sensor 1222 is a film microphone.

Optionally, the second acoustic vibration sensor 1222 includes an acoustic vibration pickup unit disposed on a plurality of locations of the ear plug.

For example, the second acoustic vibration sensor 1222 is a thin film microphone annularly disposed on the ear plug, as shown in fig. 16. Also shown in fig. 16 is a top view of the earplug. The top view of the earplug referred to herein represents a view of the side of the earplug facing the human ear. As can be seen in fig. 16, the second acoustic vibration sensor 1222 may be a ring-shaped film microphone disposed on the inner wall of the ear bud.

Fig. 17 is a schematic view of the headset 1200 shown in fig. 16 in a use state. It will be appreciated that in the use state of the headset 1200, the ear plug is located within the external auditory canal, i.e. the second acoustic vibration sensor 1222 is located in the external auditory canal space. Because the second acoustic vibration sensor 1222 is a film microphone annularly disposed on the ear plug, the second acoustic vibration sensor 1222 can collect acoustic vibration signals at multiple locations in the external auditory canal space.

Compared with the prior art, the present embodiment can be regarded as extending the single-point error signal acquisition to the error signal acquisition of more spatial positions, i.e., forming a wider range of dead zones, as shown in fig. 17. Because the range of the quiet zone is enlarged, the quiet zone can be ensured to cover the eardrum to a greater extent, so that the error signal of active noise reduction can better represent the real noise reduction effect of human ear perception, and the active noise reduction effect is enhanced.

Alternatively, as shown in fig. 18, the error sensor 1220 includes a first acoustic vibration sensor 1221, a second acoustic vibration sensor 1222, and a processing unit 1223. The first sonic vibration sensor 1221 is used to collect a sonic vibration signal at the eardrum. A second acoustic vibration sensor 1222 is disposed on the earphone earplug. The second acoustic vibration sensor 1222 is used to collect acoustic vibration signals in the external auditory canal space. And a processing unit 1223, configured to obtain an active noise reduction error signal according to the sound wave vibration signal at the eardrum collected by the first sound wave vibration sensor 1221 and the sound wave vibration signal in the external auditory canal space collected by the second sound wave vibration sensor 1222.

For example, the processing unit 1223 is configured to obtain a first error signal from the acoustic vibration signal at the eardrum collected by the first acoustic vibration sensor 1221; obtaining a second error signal from the acoustic vibration signal in the external auditory canal space collected by the second acoustic vibration sensor 1222; and obtaining an active noise reduction error signal according to the first error signal and the second error signal.

Let the first and second error signals be denoted as e1(n) and e2(n), respectively, and the actively noise-reduced error signal be denoted as e (n). The processing unit 1223 may obtain the actively noise-reduced error signal e (n) according to the following formula:

e(n)＝a1*e1(n)+a2*e2(n)

wherein a1 and a2 are weights. For example, a1 is 0.8 and a2 is 0.2. Alternatively, both a1 and a2 are 1. In engineering implementation, the values of a1 and a2 can be flexibly adjusted based on actual effects.

As an example, as shown in fig. 19, the headset 1200 includes an ear-piece, the first acoustic vibration sensor 1221 is located on the headset housing, and the second acoustic vibration sensor 1222 is a film microphone annularly disposed on the ear-piece. The controller 1210 and the processing unit 1223 are not shown in fig. 19.

The description of the first acoustic vibration sensor 1221 collecting acoustic vibration signals at the cover membrane is given above in conjunction with the description of fig. 14 and 15, and the description of the second acoustic vibration sensor 1222 collecting acoustic vibration signals in the external auditory canal space is given above in conjunction with the description of fig. 17, and will not be repeated here.

Determining an error signal for active noise reduction based on the acoustic vibration signal at the eardrum and the acoustic vibration signal in the external auditory canal space corresponds to forming a quiet zone at the eardrum and in the external auditory canal space. As shown in fig. 19, a quiet zone 1 is formed at the eardrum and a quiet zone 2 is formed in the external ear canal space.

The earphone that this embodiment provided acquires the error signal that initiatively falls makes an uproar through the sound wave vibration signal and the sound wave vibration signal in the external auditory canal space according to eardrum department, can be so that the initiative error signal who acquires is more comprehensive, more accurate to can make this error signal represent the real noise reduction effect of people's ear perception better, consequently can further improve error signal's accuracy, thereby strengthen the effect of initiatively falling the noise better.

Optionally, in some embodiments, the error sensor 1220 is further configured to collect the sound wave vibration signal of the external ear canal orifice, and to obtain an active noise reduction error signal according to the sound wave vibration signal of the inside of the human ear and the sound wave vibration signal of the external ear canal orifice.

As shown in fig. 19, the error sensor 1220 includes a first acoustic vibration sensor 1221, a second acoustic vibration sensor 1222, an acoustic sensor 1224, and a processing unit 1223. The first sonic vibration sensor 1221 is used to collect a sonic vibration signal at the eardrum. A second acoustic vibration sensor 1222 is disposed on the earphone earplug. The second acoustic vibration sensor 1222 is used to collect acoustic vibration signals in the external auditory canal space. And an acoustic sensor 1224 for collecting acoustic vibration signals of the meatus of the external ear. A processing unit 1223, configured to obtain an active noise reduction error signal according to the sound wave vibration signal at the eardrum collected by the first sound wave vibration sensor 1221, the sound wave vibration signal in the external auditory canal space collected by the second sound wave vibration sensor 1222, and the sound wave vibration signal at the external auditory canal opening collected by the acoustic sensor 1224.

For example, the processing unit 1223 is configured to obtain a first error signal from the acoustic vibration signal at the eardrum collected by the first acoustic vibration sensor 1221; obtaining a second error signal from the acoustic vibration signal in the external auditory canal space collected by the second acoustic vibration sensor 1222; acquiring a third error signal according to the sound wave vibration signal of the external ear canal orifice acquired by the acoustic sensor 1224; and obtaining an active noise reduction error signal according to the first error signal, the second error signal and the third error signal.

Let the first, second and third error signals be denoted as e1(n), e2(n) and e3(n), respectively, and the actively noise-reduced error signal be denoted as e (n). The processing unit 1223 may obtain the actively noise-reduced error signal e (n) according to the following formula:

e(n)＝a1*e1(n)+a2*e2(n)+a*e2(n)

wherein a1, a2 and a3 are weights. For example, a1 is 0.8, a2 is 0.15, and a3 is 0.05. Alternatively, a1 and a2 are both 1, and a3 is 0.5. In engineering implementation, the values of a1, a2 and a3 can be flexibly adjusted based on actual effects.

Among other things, the acoustic sensor 1224 may be an error sensor in an existing active noise reduction system, such as the error sensor 130 shown in fig. 1-4.

The earphone 1200 provided by the embodiment collects sound wave vibration signals at a plurality of positions of ears through a plurality of sensors, and then obtains active noise reduction error signals according to the sound wave vibration signals collected at the plurality of positions of ears, so that a dead zone is larger, and the active noise reduction error signals are more comprehensive and accurate, thereby improving the active noise reduction effect.

Alternatively, in embodiments where error sensor 1220 includes multiple sensors (e.g., any two or all of first acoustic vibration sensor 1221, second acoustic vibration sensor 1222, acoustic sensor 1224), and processing unit 1223, processing unit 1222 may be divided into multiple sub-processing units.

As shown in fig. 21, the error sensor 1220 includes a first acoustic vibration sensor 1221, a second acoustic vibration sensor 1222, a first sub-processing unit 1222a, a second sub-processing unit 1222b, and a third sub-processing unit 1222 c.

The first acoustic vibration sensor 1221 is configured to collect an acoustic vibration signal at an eardrum; the first sub-processing unit 1222a is used to obtain a first error signal from the acoustic vibration signal at the eardrum.

The second acoustic vibration sensor 1222 is used for collecting acoustic vibration signals in the external auditory canal space; the second sub-processing unit 1222b is for acquiring a second error signal from the acoustic vibration signal in the external auditory canal space.

The third sub-processing unit 1222c is configured to obtain an active noise reduction error signal according to the first error signal and the second error signal.

For example, in the embodiment shown in FIG. 21, the first sonic vibration sensor 1221 as a whole with the first sub-processing unit 1222a may be considered as a substructure (shown as substructure one in FIG. 21) of the error sensor 1220; the second acoustic vibration sensor 1222 and the second sub-processing unit 1222b as a whole may look at another sub-structure (e.g., the second sub-structure shown in fig. 21) in the error sensor 1220, and the third sub-processing unit 1222c may be regarded as an integrated processing module in the error sensor 1220.

Alternatively, error sensor 1220 may include one or more substructures as shown in FIG. 21, where each substructure may collect a defined error signal.

For example, the error sensor 1220 includes only one sub-structure, which is the sub-structure one or the sub-structure two shown in fig. 21, and in this example, the error sensor 1220 may not include the third sub-processing unit 1222 c.

For another example, the error sensor 1220 includes two or more sub-structures, each of which can collect a defined error signal, and in this example, the error sensor 1220 further includes a third sub-processing unit 1222c for performing comprehensive processing on the error signals obtained by the two or more sub-structures to finally obtain an error signal with active noise reduction. In this example, for example, the error sensor 1220 is shown in fig. 21, or the error sensor 1220 further includes a substructure three including an acoustic sensor and a corresponding sub-processing unit in addition to the substructure one and the substructure two shown in fig. 21.

Fig. 18, 20 and 21 are exemplary only and not limiting. The division of the internal blocks of the error sensor 1220 may be performed in various ways according to the functions that the error sensor 1220 can perform.

Fig. 18, 20, and 21 are logical block diagrams of the error sensor 1220, and the error sensor 1220 may be physically combined with a plurality of physical entities of different forms.

Optionally, as shown in fig. 13, 14, 15, 16, 17 and 19, in some embodiments, the headset 1200 may further include a reference sensor 1240 for collecting noise signals.

For example, the reference sensor 1240 may be disposed outside the earmuff, similar to the reference sensor 140 in FIG. 4, for collecting ambient noise signals.

In this embodiment, the controller 1210 is configured to determine a noise reduction signal according to the error signal acquired by the error sensor 1220 and the noise signal acquired by the reference sensor 1240.

Assuming that a noise signal collected by the reference sensor 1240 is denoted as x (n), an error signal obtained by the error sensor 1220 is denoted as e (n), and a noise reduction signal is denoted as y (n), the controller 1210 may obtain the noise reduction signal y (n) by using the following formula:

y(n)＝w ^T(n)x(n)

w(n+1)＝w(n)+u e(n)x(n)

where w (n) represents the weight or filter coefficients, and the 2 nd formula is the updated formula for w (n). u represents a convergence factor, and the value of u may be random. For example, the weight coefficient w (n +1) at the next time may be obtained by adding the weight coefficient w (n) at the current time to the input proportional to the error function (e) (n) x (n)).

For example, the controller 1210 may be a hardware circuit. For example, the controller 1210 may be an adaptive filter. Controller 1210 may be referred to as an ANC chip.

It should be noted that fig. 13, 14, 15, 16, 17, and 19 are only examples and are not limiting. As long as the active noise reduction error signal can be determined according to the sound wave vibration signal inside the human ear, the error sensor 1220 can be flexibly set according to the application requirements.

It should be further noted that, based on the principle of active noise reduction and the actual physical meaning of the error sensor, in order to achieve a more accurate noise reduction effect, the error signal acquired by the error sensor may be as close as possible to the auditory perception position or the accurate space may be larger, so that the noise reduction effect is better. Therefore, the scheme provided by the embodiment of the application can be not only limited to the active noise reduction earphone, but also applied to other active noise reduction fields.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

It should also be understood that reference herein to first or second and various numerical designations is made merely for convenience of description and does not limit the scope of the embodiments of the invention.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a read-only memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

A method of active noise reduction, comprising:

collecting sound wave vibration signals inside human ears;

obtaining an active noise reduction error signal according to the sound wave vibration signal inside the human ear;

determining a noise reduction signal according to the active noise reduction error signal, wherein the noise reduction signal is used for offsetting a noise signal;

and playing the noise reduction signal to human ears.
The method of claim 1, wherein said acquiring acoustic vibration signals inside the human ear comprises: collecting sound wave vibration signals at the eardrum.
The method of claim 2, wherein collecting the sonic vibration signal at the eardrum comprises:

emitting light towards the eardrum;

receiving light reflected by the eardrum;

and obtaining a sound wave vibration signal at the eardrum according to the light reflected by the eardrum.
The method of claim 1, wherein said acquiring acoustic vibration signals inside the human ear comprises:

collecting a sound wave vibration signal in the external auditory canal space.
The method of claim 2 or 3, wherein said collecting the sonotrode signal inside the human ear further comprises:

collecting sound wave vibration signals in the external auditory canal space;

wherein, the error signal of actively making an uproar falls according to the inside sound wave vibration signal of people's ear includes:

obtaining a first error signal according to the sound wave vibration signal at the eardrum;

obtaining a second error signal according to the sound wave vibration signal in the external auditory canal space;

and obtaining the active noise reduction error signal according to the first error signal and the second error signal.
The method according to claim 4 or 5, wherein said acquiring a sonic vibration signal in the external auditory canal space comprises:

collecting a sonic vibration signal in the external ear canal space using a vibration sensor disposed on an ear plug.
The method of claim 6, wherein the vibration sensor disposed on an earbud comprises a sonic vibration pickup unit disposed on a plurality of locations of the earbud.
The method of claim 7, wherein the earbud-disposed vibration sensor is a thin-film microphone annularly disposed on the earbud.
The method of any one of claims 1 to 8, further comprising:

collecting sound wave vibration signals of the external auditory meatus;

wherein, the error signal of actively making an uproar falls according to the inside sound wave vibration signal of people's ear includes:

and obtaining the active noise reduction error signal according to the sound wave vibration signal inside the human ear and the sound wave vibration signal at the external ear canal opening.
An active noise reduction earphone, comprising:

the error sensor is used for acquiring sound wave vibration signals inside human ears and obtaining active noise reduction error signals according to the sound wave vibration signals;

the controller is used for determining a noise reduction signal according to the active noise reduction error signal obtained by the error sensor, and the noise reduction signal is used for offsetting a noise signal;

and the loudspeaker is used for playing the noise reduction signal determined by the controller to human ears.
The headset of claim 10, wherein the error sensor comprises a first sonic vibration sensor for collecting a sonic vibration signal at the eardrum.
The headset of claim 11, wherein the first sonic vibration sensor is configured to:

emitting light towards the eardrum;

receiving light reflected by the eardrum;

and obtaining a sound wave vibration signal at the eardrum according to the light reflected by the eardrum.
The headset of claim 10, wherein the headset includes an ear bud, and wherein the error sensor includes a second acoustic vibration sensor disposed on the ear bud for collecting the acoustic vibration signal in the external auditory canal space.
The headset of claim 11 or 12, wherein the headset comprises an ear bud, the error sensor comprising a second acoustic vibration sensor disposed on the ear bud for acquiring an acoustic vibration signal in the external auditory canal space;

the error sensor further comprises a processing unit, and the processing unit is used for acquiring the active noise reduction error signal according to the sound wave vibration signal acquired by the first sound wave vibration sensor and the sound wave vibration signal acquired by the second sound wave vibration sensor in the space of the external auditory canal.
The headset of claim 13 or 14, wherein the second acoustic vibration sensor comprises an acoustic vibration pickup unit disposed at a plurality of locations of the ear bud.
The headset of claim 15, wherein the second acoustic vibration sensor is a thin film microphone disposed annularly on the earpiece.
The earphone according to any of claims 10 to 16, wherein the error sensor is further configured to collect the sound vibration signal of the external ear canal orifice and to obtain the actively noise-reduced error signal according to the sound vibration signal of the inside of the human ear and the sound vibration signal of the external ear canal orifice.