WO2022016511A1

WO2022016511A1 - Active noise cancellation method and apparatus

Info

Publication number: WO2022016511A1
Application number: PCT/CN2020/104467
Authority: WO
Inventors: 张立斌; 袁庭球
Original assignee: 华为技术有限公司
Priority date: 2020-07-24
Filing date: 2020-07-24
Publication date: 2022-01-27
Also published as: CN114467311A

Abstract

An active noise cancellation method and an earphone. The method comprises: acquiring a sound wave vibration signal inside a human ear (S610); according to the sound wave vibration signal inside the human ear, obtaining an error signal of active noise cancellation (S620); according to the error signal of active noise cancellation, determining a noise cancellation signal, the noise cancellation signal being used for cancelling a noise signal (S630); and playing the noise cancellation signal to the human ear (S640). An error signal of active noise cancellation is determined according to a sound wave vibration signal inside a human ear, such that a quiet zone is located inside the human ear and the quiet zone can cover the eardrum to some extent. Therefore, the error signal of active noise cancellation can better represent the true noise cancellation effect perceived by a human ear, so that the effect of active noise cancellation can be enhanced.

Description

Method and device for active noise reduction

technical field

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

Background technique

Active noise cancellation (ANC) is based on the principle of superposition of sound waves, and noise removal is achieved by cancelling each other of sound waves. Active noise reduction systems include feedforward and feedback. The feedback-type active noise reduction system achieves the purpose of noise reduction through feedback. Specifically, an error sensor is used to collect the error signal after the noise reduction signal and the noise signal are superimposed, and a more accurate noise reduction signal is generated according to the error signal. .

In the existing feedback active noise reduction headphones, the error sensor is usually located at the mouth of the external auditory canal, and there may be a problem that the error signal collected by the error sensor cannot well represent the real noise reduction effect perceived by the human ear, which makes the collected error The signal is not accurate enough, which affects the effect of Active Noise Cancellation.

SUMMARY OF THE INVENTION

The present application provides a method and device for active noise reduction. By obtaining an error signal according to the sound wave vibration signal inside the ear, the error signal in the feedback active noise reduction system can better represent the real noise reduction effect perceived by the human ear. , which can enhance the effect of Active Noise Cancellation.

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

Obtain the error signal of active noise reduction according to the sound wave vibration signal inside the human ear; determine the noise reduction signal according to the error signal of the active noise reduction, and the noise reduction signal is used to cancel the noise signal; play the noise reduction signal to the human ear Noise reduction signal.

In the existing active noise reduction system, the quiet zone is located at the mouth of the external auditory canal, and it is easy to occur that the quiet zone cannot cover the eardrum. It should be understood that the eardrum is the organ that collects sound. Sound waves cause the eardrum to vibrate, and the information of the eardrum vibration is transmitted to the brain, and people perceive the sound. That is, the location of the eardrum is the location of auditory perception. If the quiet zone does not cover the eardrum, the collected error signal may not represent the active noise reduction effect at the eardrum, that is, it cannot represent the real noise reduction effect perceived by the human ear, which will reduce the effect of active noise reduction.

In the present application, the error signal of active noise reduction is determined according to the sound wave vibration signal inside the human ear, so that the quiet zone is located inside the human ear. Compared with the prior art, the distance between the quiet zone and the eardrum is shortened, and to a certain extent The quiet zone can be made to cover the eardrum, therefore, the error signal of the active noise reduction can be made more representative of the real noise reduction effect perceived by the human ear, so that the effect of the active noise reduction can be enhanced.

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

Determining the error signal of active noise reduction based on the sound wave vibration signal at the eardrum is equivalent to forming a quiet zone at the eardrum, which ensures that the quiet zone covers the eardrum. Therefore, the error signal of active noise reduction can accurately represent the real perception of the human ear. Noise reduction effect, so the effect of active noise reduction can be improved.

With reference to the first aspect, in a possible implementation manner, the collecting the acoustic wave vibration signal at the eardrum includes: emitting light to the eardrum; receiving the light reflected back by the eardrum; according to the light reflected back by the eardrum , to obtain the acoustic vibration signal at the eardrum.

In the present application, determining the error signal of active noise reduction based on the acoustic vibration signal at the eardrum is equivalent to forming a quiet zone at the eardrum, so that the error signal of active noise reduction can accurately represent the real noise reduction effect perceived by the human ear, Therefore, the effect of active noise reduction can be further improved.

In addition, in the present application, since a quiet 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.

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

The error signal of active noise reduction is determined based on the acoustic vibration signal in the external auditory canal space, which is equivalent to forming a quiet zone in the external auditory canal space. Compared with the prior art, the distance between the quiet zone and the eardrum is shortened, so that the quiet zone can cover the eardrum to a certain extent. Therefore, the error signal of the active noise reduction can be more representative of the real noise reduction effect perceived by the human ear. Thereby, the effect of active noise cancellation can be enhanced.

With reference to the first aspect, in a possible implementation manner, the collecting the sound wave vibration signal inside the human ear further includes: collecting the sound wave vibration signal in the space of the external auditory canal; Obtaining an error signal of active noise reduction from the signal includes: obtaining a first error signal according to the acoustic wave vibration signal at the eardrum; obtaining a second error signal according to the acoustic wave vibration signal in the external auditory canal space; and obtaining a second error signal according to the first error signal and the The second error signal is to obtain the error signal of the active noise reduction.

Optionally, the obtaining the error signal of the active noise reduction according to the first error signal and the second error signal includes: weighting and summing the first error signal and the second error signal , to obtain the error signal of active noise reduction.

Optionally, the obtaining the error signal of the active noise reduction according to the first error signal and the second error signal includes: averaging the first error signal and the second error signal, Obtain the error signal for Active Noise Cancellation.

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

In the present application, the error signal of active noise reduction is obtained according to the acoustic wave vibration signal at the eardrum and the acoustic wave vibration signal in the external auditory canal space, which can make the acquired active error signal more comprehensive and accurate, so that the error signal can be better It represents the true noise reduction effect perceived by the human ear, so the accuracy of the error signal can be further improved, thereby better enhancing the effect of active noise reduction.

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

With reference to the first aspect, in a possible implementation manner, the collecting the acoustic wave vibration signal in the external auditory canal space includes: using a vibration sensor deployed on the earplug to collect the acoustic wave vibration signal in the external auditory canal space.

With reference to the first aspect, in a possible implementation manner, the vibration sensor deployed on the earplug includes acoustic vibration acquisition units deployed on multiple positions of the earplug.

Therefore, in the present application, the error signal of active noise reduction is obtained according to the acoustic vibration signals at multiple positions in the external auditory canal space, which can expand the scope of the quiet zone, and can make the error signal of active noise reduction closer to the true value perceived by the human ear. Noise reduction effect, which can enhance the active noise cancellation effect.

With reference to the first aspect, in a possible implementation manner, the vibration sensor deployed on the earplug is a film microphone that is annularly deployed on the earplug.

It should be understood that, in this application, the manner of collecting the acoustic vibration signal inside the human ear can be any of the following manners:

1) Only the acoustic vibration signal at the eardrum is collected;

2) Only the acoustic vibration signal in the external auditory canal space is collected;

3) Not only collecting the acoustic wave vibration signal at the eardrum, but also collecting the acoustic wave vibration signal in the external auditory canal space.

With reference to the first aspect, in a possible implementation manner, the method further includes: collecting a sound wave vibration signal at the mouth of the external auditory canal; wherein, the obtaining an error signal of active noise reduction according to the sound wave vibration signal inside the human ear includes: according to the sound wave vibration signal inside the human ear. The error signal of the active noise reduction is obtained from the sound wave vibration signal inside the human ear and the sound wave vibration signal of the external auditory canal opening.

By obtaining the error signal of active noise reduction according to the sound wave vibration signals collected at multiple places in the ear, the quiet zone can be made larger, so that the error signal of active noise reduction can be more comprehensive and accurate, and therefore, the effect of active noise reduction can be improved.

In a second aspect, an active noise reduction earphone is provided, the earphone comprising: an error sensor for collecting a sound wave vibration signal inside the human ear, and obtaining an active noise reduction error signal according to the sound wave vibration signal; a controller, for determining a noise reduction signal according to the error signal of the active noise reduction obtained by the error sensor, and the noise reduction signal is used to cancel the noise signal; a speaker is used to play the noise reduction signal determined by the controller to the human ear Noise reduction signal.

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

With reference to the second aspect, in a possible implementation manner, the first acoustic wave vibration sensor is used to: emit light to the eardrum; receive the light reflected back by the eardrum; according to the light reflected back by the eardrum, Acoustic vibration signals at the eardrum are obtained.

With reference to the second aspect, in a possible implementation manner, the earphone includes an earplug, and the error sensor includes a second acoustic vibration sensor disposed on the earplug for collecting acoustic vibration signals in the external auditory canal space.

With reference to the second aspect, in a possible implementation manner, the earphone includes an earplug, and the error sensor includes a second acoustic vibration sensor disposed on the earplug, for collecting acoustic vibration signals in the external auditory canal space; The error sensor also includes a processing unit, configured to obtain the sound wave vibration signal in the external auditory canal space according to the sound wave vibration signal at the eardrum collected by the first sound wave vibration sensor and the sound wave vibration signal in the external auditory canal space collected by the second sound wave vibration sensor. The active noise reduction error signal.

With reference to the second aspect, in a possible implementation manner, the second acoustic vibration sensor includes acoustic vibration acquisition units deployed on multiple positions of the earplug.

With reference to the second aspect, in a possible implementation manner, the second acoustic wave vibration sensor is a thin-film microphone annularly disposed on the earplug.

In conjunction with the second aspect, in a possible implementation manner, the error sensor is also used to collect the acoustic vibration signal of the external auditory canal orifice, and used to collect the acoustic vibration signal from the human ear and the acoustic vibration of the external auditory canal orifice. signal to obtain the error signal of the active noise reduction.

Optionally, in the active noise reduction earphone provided by the second aspect, the operation of obtaining the error signal of the active noise reduction according to the collected sound wave vibration signal inside the human ear can be performed by an error sensor or by other processing units. , the other processing unit may be the controller directly, or may be another processing unit inside the headset. For example, the earphone further includes an intermediate processing unit, configured to obtain an error signal of active noise reduction according to the sound wave vibration signal.

It should be noted that, in practical applications, the operation of obtaining the error signal of active noise reduction according to the collected acoustic vibration signals inside the human ear is performed by which unit or module inside the headset may depend on the design principle of the error sensor inside the headset. .

For example, the error sensor may be configured to acquire the sonic vibration signal and output the acquired signal directly without further processing the sonic vibration signal. In this case, the operation of obtaining the error signal of active noise reduction according to the sound wave vibration signal may be performed by other units or modules inside the earphone.

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

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

Based on the above description, in the present application, the error signal of active noise reduction is determined according to the sound wave vibration signal inside the human ear, so that the quiet zone is located inside the human ear. Compared with the prior art, the distance between the quiet zone and the eardrum is shortened, To a certain extent, the quiet zone can be made to cover the eardrum. Therefore, the error signal of the active noise reduction can be more representative of the real noise reduction effect perceived by the human ear, thereby enhancing the effect of the active noise reduction.

Description of drawings

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

FIG. 2 is a schematic diagram of the principle of the active noise reduction system.

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

FIG. 4 is a schematic diagram of the shape of an earphone of the active noise reduction system shown in FIG. 1 .

FIG. 5 is a schematic diagram illustrating the formation of a quiet zone by an existing active noise reduction system.

FIG. 6 is a schematic flowchart of a method for active noise reduction provided by an embodiment of the present application.

FIG. 7 is another schematic flowchart of the method for active noise reduction provided by an embodiment of the present application.

8 and 9 are schematic diagrams of the principle of optical detection of acoustic vibration.

FIG. 10 is another schematic flowchart of the method for active noise reduction provided by an embodiment of the present application.

FIG. 11 is still another schematic flowchart of the method for active noise reduction provided by an embodiment of the present application.

FIG. 12 is a schematic flowchart of an active noise reduction earphone provided by an embodiment of the present application.

FIG. 13 is a schematic diagram of a product form of an active noise reduction earphone provided by an embodiment of the present application.

14 and 15 are schematic diagrams of the earphone shown in FIG. 13 in use.

FIG. 16 is a schematic diagram of another product form of the active noise reduction earphone provided by the embodiment of the application.

17 and 16 are schematic diagrams of the earphones in use.

FIG. 18 is a schematic block diagram of an error sensor in an active noise reduction earphone provided by an embodiment of the present application.

FIG. 19 is a schematic diagram of another product form of the active noise reduction earphone provided by the embodiment of the application.

FIG. 20 is another schematic block diagram of an error sensor in an active noise reduction earphone provided by an embodiment of the present application.

FIG. 21 is still another schematic block diagram of an error sensor in an active noise reduction earphone provided by an embodiment of the present application.

detailed description

Active noise cancellation (ANC) is a technology based on the principle of superposition of sound waves to achieve noise removal by cancelling each other of sound waves. Active noise reduction systems include feedforward type and feedback type, and this application only relates to feedback type active noise reduction systems. Unless otherwise specified, the active noise reduction mentioned in the embodiments of the present application refers to 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 below with reference to FIG. 1 , FIG. 2 , FIG. 3 and FIG. 4 .

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

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

Step ①, the error sensor 130 collects the error signal e(n), and transmits the error signal e(n) to the controller 110 .

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

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

Step ②, 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. Ambient noise signals are often emitted by undesired noise sources, as shown in Figure 2.

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

Step ③, the controller 110 calculates an error cost function based on the error signal e(n), and predicts the noise reduction signal y(n) output by the speaker 120 based on the noise signal x(n) based on the principle of minimizing the error cost function.

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

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

Step ④, the speaker 120 sends out the noise reduction signal y(n) according to the control of the controller 110 .

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

As shown in FIG. 3 , what the error sensor 130 collects is the superimposed sound signal after the noise signal x(n) and the noise reduction signal y(n) pass through the primary path and the secondary path respectively and reach the quiet zone. The sound signal is called is the error signal e(n). The noise signal e(n) collected by the error sensor 130 can also be described as residual noise after noise reduction processing.

The goal of the controller 110 predicting the noise reduction signal y(n) output by the speaker 120 is to make the noise signal x(n) and the noise reduction signal y(n) pass through the primary path and the secondary path respectively and reach the quiet zone after the superimposed signal The error cost function of e(n) is the smallest.

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

Usually, the product form of the active noise reduction system is a headset, as an example, as shown in Figure 4. The reference sensor 140 is arranged on the earphone cover and is used to collect ambient noise signals. The error sensor 130 is arranged in the earphone cover, and is used for collecting the error signal after noise reduction processing. The controller 110 is arranged in the earphone cover, and is used for predicting the noise reduction signal output by the speaker 120 according to the noise signal and the error signal. The speaker 120 is arranged in the earphone cover, and plays the noise reduction signal predicted by the controller 110 . The valid input sound signals shown in FIG. 4 represent the signals that the user wants to play, eg, music or call signals.

It should be understood that in the earphone playing scenario shown in FIG. 4 , the sound signal reaching the human ear includes an effective sound signal, such as music or a call, in addition to the environmental noise signal and the noise reduction signal. In this headset playback scenario, in the process of acquiring the error signal, the valid sound signal will be eliminated. For example, by means of signal processing, the effective sound signal is eliminated to obtain the residual noise after active noise reduction, that is, the error signal. When the error signal is obtained, it is the prior art to reject the effective sound signal, which will not be described in detail in this paper.

2 to 4 are only examples and not limitation. For example, the primary channel and the secondary channel shown in Figure 2 are only to distinguish the propagation paths of the noise signal x(n) and the noise reduction signal y(n), and do not represent the physical existence of the primary channel and the noise reduction signal in the active noise reduction system. secondary channel.

It should be understood that the superposition effects of the noise signal and the noise reduction signal at different positions are not necessarily the same. Suppose that the error sensor collects the error signal at point A, which can represent the superposition effect of the noise signal and the noise reduction signal at point A, but not necessarily the superposition effect of the noise signal and the noise reduction signal at other positions other than point A . In order to express which area of active noise reduction effect is represented by the error signal of active noise reduction, the concept of quiet zone is proposed, which represents the area or space where the error signal collected by the error sensor is located. That is to say, where the error sensor collects the signal, there is the quiet zone. For example, in FIG. 2, the dead zone represents the region where the error signal e(n) collected by the error sensor 130 is located.

It should also be understood that the goal of the controller 110 to predict the noise reduction signal y(n) output by the speaker 120 is to make the noise reduction signal y(n) and the noise signal x(n) respectively reach the quiet zone and the superposed signal e( n) has the smallest error cost function. That is to say, the active noise reduction system aims to achieve the active noise reduction effect in the quiet zone.

In the existing active noise reduction system, the error sensor is an acoustic sensor (such as a microphone). Therefore, the location where the error sensor collects the signal is the location where the error sensor is located, that is, the location where the error sensor is located is the location of the quiet zone. In the existing active noise reduction system, the error sensor is located at the external auditory canal opening of the human ear, as shown in FIG. 5 . Therefore, the quiet zone is located at the external auditory canal opening.

In the case that the active noise reduction system has only one secondary sound source (the active noise reduction system usually sets only one secondary sound source), the size of the quiet zone is related to the frequency (ie wavelength intensity) of the audio signal (ie the sound wave signal). For example, the diameters of the quiet zones of acoustic signals at different frequencies are:

500Hz sound wave signal, the diameter of the quiet zone is about 7 centimeters (cm);

5000Hz sound wave signal, the diameter of the quiet zone is about 0.7cm;

For a sound wave signal of 10000Hz, the diameter of the quiet zone is about 0.34cm.

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

Continue to see Figure 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 a 500 Hz acoustic signal (a quiet zone with a diameter of about 7 cm). The high-frequency quiet zone in FIG. 5 represents a quiet zone corresponding to a higher frequency acoustic signal, for example, a quiet zone corresponding to a 10000 Hz acoustic signal (a quiet zone with a diameter of about 0.34 cm).

From the above description about the relationship between the size of the quiet zone and the frequency of the acoustic signal, and Figure 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, that is, the size of the high-frequency quiet zone is smaller than that of the low-frequency quiet zone. size.

As described above, in the existing active noise reduction system, the quiet zone is located at the orifice of the external auditory canal, and it is easy to occur that the quiet zone cannot cover the eardrum. As shown in Figure 5, the high-frequency quiet zone does not cover the location of the eardrum.

It should be understood that the eardrum is the organ that collects sound. Sound waves cause the eardrum to vibrate, and the information of the eardrum vibration is transmitted to the brain, and people perceive the sound. That is, the location of the eardrum is the location of auditory perception.

If the quiet zone does not cover the eardrum, the collected error signal may not represent the active noise reduction effect at the eardrum, that is, it cannot represent the real noise reduction effect perceived by the human ear, which will reduce the effect of active noise reduction. For example, the existing active noise reduction system at least has a poor effect on the active noise reduction of high-frequency sound signals.

In view of the above technical problems, an embodiment of the present application proposes an active noise reduction solution. By obtaining an error signal of active noise reduction according to the sound wave vibration signal inside the ear, the error signal can be more representative of the real noise reduction effect perceived by the human ear. Therefore, the active noise reduction effect can be enhanced.

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

FIG. 6 is a schematic flowchart of a method 600 for active noise reduction provided by an embodiment of the present application. For example, the execution subject of the method 600 is an earphone. The method 600 includes steps S610, S620, S630 and S640.

S610, collect the acoustic vibration signal inside the human ear.

The sound wave vibration signal inside the human ear represents the vibration signal caused by the sound wave inside the human ear. That is to say, the sound wave vibration signal inside the human ear represents the information of the sound wave reaching the inside of the human ear.

As shown in FIG. 5 , the internal structure of the human ear includes the external auditory canal and the eardrum. The inside of the human ear refers to the space of the external auditory canal, not just the opening of the external auditory canal. In step S620, the collected acoustic vibration signals inside the human ear may include acoustic vibration signals in the external auditory canal space, and/or acoustic vibration signals at the eardrum.

The sound wave vibration signal in the external auditory canal space is characterized, and the sound wave reaching the inside of the human ear causes the air in the external auditory canal space to vibrate.

The sound wave vibration signal at the eardrum indicates that the sound wave reaching the inside of the human ear causes the eardrum to vibrate.

S620, an error signal of active noise reduction is obtained according to the sound wave vibration signal inside the human ear.

The error signal of the active noise reduction represents the sound signal after the active noise reduction processing (ie, the noise reduction signal and the ambient noise signal are superimposed). The error signal of the active noise reduction can also be described as the residual signal processed by the active noise reduction. The error signal represents the active noise reduction effect of the quiet zone.

The sound wave vibration signal inside the human ear represents the vibration signal caused by the sound wave reaching the inside of the human ear, and the vibration signal represents the information of the sound wave. That is to say, the collected sound wave vibration signal inside the human ear represents the information of the sound wave reaching the inside of the human ear.

For example, the error signal of active noise reduction can be obtained according to the acoustic vibration signal inside the human ear by means of direct mapping.

It should be understood that other methods can also be used to obtain the error signal of active noise reduction according to the sound wave vibration signal inside the human ear, which is not limited in the embodiment of the present application, as long as the finally obtained error signal can represent the noise of the quiet zone after active noise reduction. noise reduction effect.

S630: Determine the noise reduction signal according to the error signal of the active noise reduction.

The process of determining the noise reduction signal according to the error signal of active noise reduction is similar to the process of obtaining the noise reduction signal y(n) according to the error signal e(n) in FIG. Not detailed.

S640, play the noise reduction signal to the human ear.

For example, the execution subject of the method 600 provided in this embodiment of the present application is a feedback active noise reduction headset, steps S610 and S620 may be performed by an error sensor in the earphone, step S630 may be performed by a controller in the earphone, and step S640 may be performed by The speaker inside the headset performs.

As described above, in the existing active noise reduction system, the quiet zone is located at the orifice of the external auditory canal, and it is easy to occur that the quiet zone cannot cover the eardrum.

In the embodiment of the present application, the error signal of active noise reduction is determined according to the sound wave vibration signal inside the human ear, so that the quiet zone is located inside the human ear. Compared with the prior art, the distance from the quiet zone to the eardrum is shortened. To a certain extent, the quiet zone can cover the eardrum, and therefore, the error signal of the active noise reduction can be more representative of the real noise reduction effect perceived by the human ear, thereby enhancing the effect of the active noise reduction.

Optionally, as shown in FIG. 7 , step S610 includes: collecting an acoustic wave vibration signal at the eardrum; correspondingly, in step S620 , an error signal of active noise reduction is obtained according to the acoustic wave vibration signal at the eardrum.

For example, the error signal of active noise reduction can be obtained according to the acoustic vibration signal at the eardrum by means of direct mapping.

It should be understood that other methods can also be used to obtain the error signal of active noise reduction according to the acoustic wave vibration signal at the eardrum, which is not limited in the embodiments of the present application, as long as the finally obtained error signal can represent the reduction of the quiet zone after active noise reduction. noise effect.

Determining the error signal of active noise reduction based on the sound wave vibration signal at the eardrum is equivalent to forming a quiet zone at the eardrum, that is, it can ensure that the quiet zone covers the eardrum. Therefore, the error signal of active noise reduction can accurately represent the real perception of the human ear. Noise reduction effect, so the effect of active noise reduction can be improved.

There are many ways to collect the acoustic vibration signal at the eardrum.

Optionally, the principle of light detection of sound wave vibration can be used to collect the sound wave vibration signal at the eardrum.

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

In order to better understand this embodiment, the principle of optically detecting acoustic vibration is exemplarily described below with reference to FIG. 8 and FIG. 9 .

FIG. 8 is a schematic diagram of a light detection acoustic vibration system. The light detection acoustic wave vibration system includes a light transmitter, a light reflector, a light receiver and a photoelectric converter. Light reflectors are objects that are easily vibrated by sound pressure around the detection target. The light emitter emits light onto the light reflector. The light receiver detects the light reflected back by the light 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 acoustic wave information. The photoelectric converter can obtain acoustic wave information by demodulating the light reflected back by the light reflector.

Replacing the light reflector in Figure 8 with the eardrum, the principle of vibration pickup is the same. The light transmitter emits light onto the eardrum. The light receiver detects the light reflected back by the eardrum. The eardrum modulates the light by the vibrations produced by the sound pressure, so the light reflected back by the light reflector carries the sound wave information. The photoelectric converter can obtain the acoustic vibration signal of the eardrum by demodulating the light reflected back by the light reflector. Specifically, the vibration of the eardrum will cause different degrees of light deflection, and the size of the light spot formed on the photoelectric converter will be different. The size of the light spot will form a current, and the magnitude of the current has a linear relationship with the vibration of the sound wave. Therefore, the current information obtained on the photoelectric converter is the acoustic vibration signal at the eardrum.

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

Assuming that the sound wave vibration is L(t), the sound pressure at a particle of the thin film medium (ie glass) is P(x, y), the glass is translated by the sound pressure as X(t), and the translation of the reflected light is Y(t), The 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 ₁ L(t)

Among them, k ₁ is a constant coefficient about the acoustic wave transmission distance and the air environment. The motion of the surface of the medium is proportional to the sound pressure acting on this particle, and the medium is translated. And if the frequency of the sound is different and the intensity is different, the degree of vibration caused is also different.

The translation of the glass by the sound pressure is:

X(t)=k ₂ P(x,y,t)

where k ₂ is a constant coefficient related to the medium. When the medium undergoes translational vibration, the incident angle does not change, but the incident point translates with the medium, and the reflected light also translates.

The translation of the reflected light is:

Y(t)=2X(t) sinθ

where sinθ is a constant.

The instantaneous change of the spot area on the photosensitive surface of the photodetector is S(t)=k ₃ Y(t), then the output current of the detector is I(t)=k ₄ S(t), where k ₄ is the difference between the detector and the detector. Constants related to own parameters.

In summary, the detector output current is:

I(t)=2k ₁ k ₂ k ₃ k ₄ L(t) sinθ

In the above formula, k ₁ , k ₂ , k ₃ , k ₄ and sinθ are all constants, and the output current of the detector has a linear relationship with the acoustic vibration, that is, the acoustic signal is collected by recording the electrical signal.

Replacing the glass in Figure 9 with the eardrum, the principle of vibration pickup is the same. When the principle shown in FIG. 9 is applied to the acquisition of the acoustic vibration signal at the eardrum in this embodiment, the light emitted to the eardrum may be infrared light (wavelength is 800 nanometers (nm)) or other low-wavelength light. For example, infrared rays are sent to the eardrum with an emission intensity no higher than 0.01 milliwatts (mw).

It should be noted that, with the future technological evolution, other feasible methods may also be used to collect the acoustic vibration signal at the eardrum. The solution of obtaining the error signal of active noise reduction according to the acoustic wave vibration signal at the eardrum falls within the protection scope of the present application.

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

In addition, in this embodiment, since a quiet 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.

Optionally, as shown in FIG. 10 , step S610 includes: collecting the acoustic wave vibration signal in the external auditory canal space; correspondingly, in step S620 , obtaining an error signal of active noise reduction according to the acoustic wave vibration signal in the external auditory canal space.

For example, the error signal of active noise reduction can be obtained according to the acoustic vibration signal in the external auditory canal space by means of direct mapping.

It should be understood that other methods can also be used to obtain the error signal of active noise reduction according to the acoustic 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 of the quiet zone after active noise reduction. noise reduction effect.

For example, acoustic vibration signals in the external auditory canal space can be collected using vibration sensors deployed on the earbuds.

It should be understood that the earplug is located in the external auditory canal in the use state, therefore, the vibration sensor deployed on the earplug can collect sound vibration signals in the external auditory canal space.

For example, the vibration sensor deployed on the earbud can be a membrane microphone. The principle of the film microphone is the piezoelectric principle. The principle that the film microphone collects the sound wave vibration signal is the prior art, which will not be described in detail in this article.

Optionally, in step S610, the acoustic vibration signals at multiple points in the external auditory canal space are collected.

For example, acoustic vibration signals in the external auditory canal space may be collected using acoustic vibration acquisition units deployed at multiple locations of the earplug. For example, acoustic vibration signals in the space of the external auditory canal are collected using a thin-film microphone that is annularly deployed on the earbud.

It should be understood that the acoustic wave vibration signals at multiple locations in the external auditory canal space may represent information of the acoustic waves arriving at multiple locations in the external auditory canal space. The error signal of active noise reduction obtained according to the acoustic vibration signals at multiple positions in the external auditory canal space represents the acoustic signal energy in a larger space in the external auditory canal space.

In the existing active noise reduction system, the error signal collected by the error sensor is single-point collection, as shown in FIG. 5 .

Compared with the prior art, this embodiment can be regarded as extending the error signal collection of a single point to the error signal collection of more spatial positions, that is, a larger-range quiet zone can be formed. Because the range of the quiet zone is increased, the quiet zone can be guaranteed to cover the eardrum to a greater extent, so that the error signal of the active noise reduction can better represent the real noise reduction effect perceived by the human ear, thereby enhancing the effect of active noise reduction. Effect.

Therefore, in this embodiment, the error signal of the active noise reduction is obtained according to the acoustic vibration signals at multiple positions in the external auditory canal space, which can expand the range of the quiet zone and make the error signal of the active noise reduction closer to that perceived by the human ear. True noise-cancellation, which enhances active noise-cancellation.

It should be understood that with the development of technology, other feasible methods can also be used to collect the acoustic vibration signal in the external auditory canal space. The solution of obtaining the error signal of active noise reduction according to the acoustic wave vibration signal in the external auditory canal space falls within the protection scope of the present application.

Optionally, as shown in FIG. 11 , step S610 includes: collecting acoustic wave vibration signals at the eardrum, and collecting acoustic wave vibration signals in the external auditory canal space; wherein step S620 includes steps S621 , S622 and S623 .

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

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

S622: Obtain a second error signal according to the acoustic vibration signal in the external auditory canal space.

For example, an error signal can be obtained as the second error signal according to the acoustic vibration signal at the eardrum by means of direct mapping.

S623: Obtain an error signal of active noise reduction 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 added to obtain an error signal of active noise reduction.

It should be understood that the first error signal and the second error signal may be comprehensively processed in other manners according to application requirements, so as to obtain an error signal with active noise reduction.

In the embodiment of FIG. 11 , for the description of the acquisition of the acoustic vibration signal at the eardrum and the description of the acquisition of the acoustic vibration signal in the external auditory canal space, refer to the above, and will not be repeated here.

The error signal of active noise reduction is determined based on the sound wave vibration signal at the eardrum and the sound wave vibration signal in the external auditory canal space, which is equivalent to forming a quiet zone at the eardrum and the external auditory canal space.

In this embodiment, the error signal of active noise reduction is obtained according to the acoustic wave vibration signal at the eardrum and the acoustic wave vibration signal in the external auditory canal space, which can make the acquired active error signal more comprehensive and accurate, so that the error signal can be better It represents the true noise reduction effect perceived by the human ear, so the accuracy of the error signal can be further improved, thereby better enhancing the effect of active noise reduction.

It should be understood that this embodiment can achieve higher frequency active noise reduction, and can also achieve a more stable active noise reduction effect.

Based on the above description, it can be known that, in the embodiment of the present application, the mode of collecting the acoustic wave vibration signal inside the human ear can be any one of the following modes 1), 2) and 3).

1), only the acoustic vibration signal at the eardrum is collected, as shown in the embodiment shown in FIG. 7 .

2), only the acoustic vibration signal in the external auditory canal space is collected, as shown in the embodiment shown in FIG. 10 .

3), not only collecting the sound wave vibration signal at the eardrum, but also collecting the sound wave vibration signal in the external auditory canal space, as shown in the embodiment shown in FIG. 11 .

Optionally, in the embodiment shown in FIG. 6 , the method 600 may further include: collecting the acoustic wave vibration signal of the external auditory canal opening; wherein, step S620 includes: according to the acoustic wave vibration signal inside the human ear and the acoustic wave vibration signal of the external auditory canal opening, obtaining Error signal for active noise reduction.

For example, the method shown in FIG. 5 can be used to collect the acoustic vibration signal of the external auditory canal opening.

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

For example, assuming that the noise signal is x(n) and the error signal is e(n), the minimum mean square error algorithm can be used to calculate the noise reduction signal based on x(n) and e(n).

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

Based on the above description, in the embodiment of the present application, the error signal of active noise reduction is determined according to the sound wave vibration signal inside the human ear, so that the quiet zone is located inside the human ear. Compared with the prior art, the distance between the quiet zone and the eardrum is narrowed. The distance can make the quiet zone cover the eardrum to a certain extent. Therefore, the error signal of active noise reduction can be more representative of the real noise reduction effect perceived by the human ear, thereby enhancing the effect of active noise reduction.

The active noise reduction method provided by the embodiments of the present application can be applied to earphones. The earphones to which the embodiments of the present application can be applied may have various forms, such as open type, closed type, earmuff type, earhook type, earplug type, and earplug type.

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

The error sensor 1220 is used to collect the sound wave vibration signal inside the human ear, and obtain the error signal of active noise reduction according to the sound wave vibration signal.

The controller 1210 is configured to determine the noise reduction signal according to the error signal of the active noise reduction obtained by the error sensor 1220, and the noise reduction signal is used to cancel the noise signal.

The speaker 1230 is used to play 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 active noise reduction earphone 1200 provided by the embodiment of the present application determines the error signal of the active noise reduction according to the sound wave vibration signal inside the human ear, so that the quiet zone is located inside the human ear. Compared with the prior art, the quiet zone is narrowed to The distance of the eardrum can make the quiet zone cover the eardrum to a certain extent. Therefore, the error signal of the active noise reduction can be more representative of the real noise reduction effect perceived by the human ear, thereby enhancing the effect of active noise reduction.

Optionally, the operation of obtaining the error signal of active noise reduction according to the collected acoustic vibration signals inside the human ear can be performed by the error sensor 1220 or by other processing units, and the other processing units can be directly the controller 1210, or It could be another processing unit inside the headset 1200 . For example, the earphone 1200 further includes an intermediate processing unit for obtaining an error signal of active noise reduction according to the acoustic vibration signal.

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

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

As shown in FIG. 13 , the first acoustic wave vibration sensor 1221 is located on the earphone casing. Controller 1210 is not shown in FIG. 13 .

Optionally, the first acoustic wave vibration sensor 1221 may use the principle shown in FIG. 8 and FIG. 9 to collect the acoustic wave vibration signal at the eardrum.

As shown in FIG. 14 and FIG. 15 , the first acoustic wave vibration sensor 1221 is used to: emit light to the eardrum; receive the light reflected back by the eardrum; and obtain the acoustic vibration signal at the eardrum according to the light reflected back by the eardrum.

For example, the first acoustic wave vibration sensor 1221 includes a light transmitter, a light receiver, and a photoelectric converter. Light emitters are used to emit light towards the eardrum. The light receiver is used to receive the light reflected back from the eardrum. The photoelectric converter is used to obtain the acoustic vibration signal at the eardrum according to the light received by the light receiver.

The error signal of active noise reduction is determined based on the acoustic vibration signal at the eardrum, which is equivalent to forming a quiet zone at the eardrum, as shown in Figure 14.

In the earphone 1200 provided in this embodiment, the error signal of active noise reduction can be determined according to the sound wave vibration signal at the eardrum, which is equivalent to forming a quiet zone at the eardrum, so that the error signal of active noise reduction can accurately represent the real perception of the human ear. Noise reduction effect, so the effect of active noise reduction can be further improved.

In addition, since the earphone 1200 provided in this embodiment can form a quiet zone at the eardrum, the active noise reduction effect can be enhanced for both low-frequency sound signals and high-frequency sound signals.

Optionally, as shown in FIG. 16 , the earphone 1200 includes an earplug, and the error sensor 1220 includes a second acoustic vibration sensor 1222 disposed on the earplug for collecting acoustic vibration signals in the external auditory canal space. 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 acoustic vibration acquisition units deployed at multiple locations of the earplug.

For example, the second acoustic vibration sensor 1222 is a thin-film microphone annularly deployed on the earplug, as shown in FIG. 16 . A top view of the earplug is also given in FIG. 16 . The top view of the earplug referred to here represents a view of the side of the earplug facing the human ear. As can be seen from FIG. 16 , the second acoustic wave vibration sensor 1222 may be a thin-film microphone annularly disposed on the inner wall of the earplug.

FIG. 17 is a schematic diagram of the earphone 1200 shown in FIG. 16 in a use state. It should be understood that when the earphone 1200 is in use, the earplug is located in the external auditory canal, that is, the second acoustic wave vibration sensor 1222 is located in the external auditory canal space. Because the second acoustic vibration sensor 1222 is a thin-film microphone annularly disposed on the earplug, the second acoustic vibration sensor 1222 can collect acoustic vibration signals at multiple positions in the external auditory canal space.

Compared with the prior art, this embodiment can be regarded as extending the error signal collection of a single point to the error signal collection of more spatial positions, that is, a larger range of quiet zones can be formed, as shown in FIG. 17 . Because the range of the quiet zone is increased, the quiet zone can be guaranteed to cover the eardrum to a greater extent, so that the error signal of the active noise reduction can better represent the real noise reduction effect perceived by the human ear, thereby enhancing the effect of active noise reduction. Effect.

Optionally, as shown in FIG. 18 , the error sensor 1220 includes a first acoustic wave vibration sensor 1221 , a second acoustic wave vibration sensor 1222 and a processing unit 1223 . The first acoustic vibration sensor 1221 is used to collect acoustic vibration signals at the eardrum. The second acoustic vibration sensor 1222 is deployed on the earbud of the earphone. The second acoustic vibration sensor 1222 is used to collect acoustic vibration signals in the external auditory canal space. The processing unit 1223 is configured to obtain an error signal of active noise reduction according to the acoustic vibration signal at the eardrum collected by the first acoustic vibration sensor 1221 and the acoustic vibration signal in the external auditory canal space collected by the second acoustic vibration sensor 1222 .

For example, the processing unit 1223 is configured to obtain the first error signal according to the sound wave vibration signal at the eardrum collected by the first sound wave vibration sensor 1221; and obtain the second error signal according to the sound wave vibration signal in the external auditory canal space collected by the second sound wave vibration sensor 1222 signal; according to the first error signal and the second error signal, the error signal of active noise reduction is obtained.

It is assumed that the first error signal and the second error signal are denoted as e1(n) and e2(n) respectively, and the error signal of active noise reduction is denoted as e(n). The processing unit 1223 can obtain the error signal e(n) of active noise reduction according to the following formula:

e(n)=a1*e1(n)+a2*e2(n)

Among them, a1 and a2 are weights. For example, a1 is 0.8 and a2 is 0.2. Alternatively, both a1 and a2 are 1. During engineering implementation, the values of a1 and a2 can be flexibly adjusted based on the actual effect.

As an example, as shown in FIG. 19 , the earphone 1200 includes an earplug, the first acoustic wave vibration sensor 1221 is located on the earphone shell, and the second acoustic wave vibration sensor 1222 is a film microphone annularly disposed on the earplug. The controller 1210 and the processing unit 1223 are not shown in FIG. 19 .

For the description of the first acoustic wave vibration sensor 1221 to collect the acoustic wave vibration signal at the cover film, please refer to the description above in conjunction with FIG. 14 and FIG. 15 . See the above description in conjunction with FIG. 17 , which will not be repeated here.

The error signal of active noise reduction is determined based on the sound wave vibration signal at the eardrum and the sound wave vibration signal in the external auditory canal space, which is equivalent to forming a quiet zone at the eardrum and 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 auditory canal space.

In the earphone provided by this embodiment, by obtaining the error signal of active noise reduction according to the sound wave vibration signal at the eardrum and the sound wave vibration signal in the external auditory canal space, the obtained active error signal can be made more comprehensive and accurate, so that the error signal can be made more comprehensive and accurate. It better represents the true noise reduction effect perceived by the human ear, so the accuracy of the error signal can be further improved, thereby better enhancing the effect of active noise reduction.

Optionally, in some embodiments, the error sensor 1220 is also used to collect the acoustic vibration signal of the external auditory canal orifice, and to obtain the error signal of active noise reduction according to the acoustic vibration signal inside the human ear and the acoustic vibration signal of the external auditory canal opening. .

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 acoustic vibration sensor 1221 is used to collect acoustic vibration signals at the eardrum. The second acoustic vibration sensor 1222 is deployed on the earbud of the earphone. The second acoustic vibration sensor 1222 is used to collect acoustic vibration signals in the external auditory canal space. The acoustic sensor 1224 is used to collect the acoustic vibration signal of the external auditory canal opening. The processing unit 1223 is used for the acoustic vibration signal at the eardrum collected by the first acoustic vibration sensor 1221, the acoustic vibration signal in the external auditory canal space collected by the second acoustic vibration sensor 1222, and the acoustic vibration signal of the external auditory canal orifice collected by the acoustic sensor 1224. , to obtain the error signal of active noise reduction.

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

It is assumed that the first error signal, the second error signal and the third error signal are denoted as e1(n), e2(n) and e3(n) respectively, and the error signal of active noise reduction is denoted as e(n). The processing unit 1223 can obtain the error signal e(n) of active noise reduction according to the following formula:

e(n)=a1*e1(n)+a2*e2(n)+a*e2(n)

Among them, 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. During project implementation, the values of a1, a2 and a3 can be flexibly adjusted based on the actual effect.

The acoustic sensor 1224 may be an error sensor in an existing active noise reduction system, such as the error sensor 130 shown in FIGS. 1 to 4 .

The earphone 1200 provided in this embodiment collects sound wave vibration signals from multiple parts of the ear through a plurality of sensors, and then obtains an error signal for active noise reduction according to the sound wave vibration signals collected from multiple places on the ear, which can make the quiet zone larger, so that the active noise reduction can be made larger. The error signal of noise is more comprehensive and accurate, therefore, the effect of active noise reduction can be improved.

Optionally, in an embodiment where the error sensor 1220 includes a variety of sensors (eg, any two or all of the first sonic vibration sensor 1221, the second sonic vibration sensor 1222, and the acoustic sensor 1224) and the processing unit 1223, The processing unit 1222 may be divided into multiple sub-processing units.

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

The first acoustic wave vibration sensor 1221 is used for collecting the acoustic wave vibration signal at the eardrum; the first sub-processing unit 1222a is used for acquiring the first error signal according to the acoustic wave vibration signal at the eardrum.

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

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

For example, in the embodiment shown in FIG. 21 , the first acoustic wave vibration sensor 1221 and the first sub-processing unit 1222a as a whole can be regarded as a sub-structure of the error sensor 1220 (sub-structure 1 shown in FIG. 21 ) The second acoustic wave vibration sensor 1222 and the second sub-processing unit 1222b as a whole can be regarded as another sub-structure in the error sensor 1220 (sub-structure 2 shown in FIG. 21 ), and the third sub-processing unit 1222c can be regarded as an error Integrated processing module in sensor 1220.

Optionally, the error sensor 1220 may include one or more substructures as shown in FIG. 21 , wherein each substructure may acquire a defined error signal.

For example, the error sensor 1220 only includes one substructure, which is the first substructure or the second substructure shown in FIG. 21 . In this example, the error sensor 1220 may not include the third sub-processing unit 1222c.

For another example, the error sensor 1220 includes two or more sub-structures, and each sub-structure can collect a defined error signal. In this example, the error sensor 1220 further includes a third sub-processing unit 1222c for processing two Or the error signals obtained by two or more sub-structures are comprehensively processed, and finally the error signal of active noise reduction is obtained. In this example, for example, the error sensor 1220 is shown in FIG. 21 , or the error sensor 1220 includes sub-structure 3 in addition to sub-structure 1 and sub-structure shown in FIG. 21 , and sub-structure 3 includes an acoustic sensor with the corresponding sub-processing unit.

FIG. 18 , FIG. 20 and FIG. 21 are only examples and not limitations. According to the functions that the error sensor 1220 can implement, the internal modules of the error sensor 1220 can be divided in various ways.

It should also be noted that FIG. 18 , FIG. 20 and FIG. 21 are logical structural diagrams of the error sensor 1220 , and the error sensor 1220 may physically be composed of a plurality of physical entities of different shapes.

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

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

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

Assuming that the noise signal collected by the reference sensor 1240 is denoted as x(n), the error signal obtained by the error sensor 1220 is denoted as e(n), and the noise reduction signal is denoted as y(n), the controller 1210 can use the following formula , get the noise reduction signal y(n):

y(n)=w ^T (n)x(n)

w(n+1)=w(n)+ue(n)x(n)

Among them, w(n) represents the weight coefficient or filter coefficient, and the second formula is the update formula of w(n). u represents the convergence factor, and the value of u can be random. For example, the weight coefficient w(n+1) at the next moment can be obtained by adding the weight coefficient w(n) at the current moment and an 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. The controller 1210 may be referred to as an ANC chip.

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

It should also be 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 collected by the error sensor can be as close as possible to the auditory perception position or the precise space is larger, so as to achieve a more accurate noise reduction effect. Make the noise reduction effect better. Therefore, the solutions provided by the embodiments of the present application may not only be limited to active noise reduction headphones, but may also be applied to other active noise reduction fields.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein in the specification of the application are for the purpose of describing specific embodiments only, and are not intended to limit the application.

It should also be understood that the first or second and various numerical numbers involved in this document are only for the convenience of description, and are not used to limit the scope of the embodiments of the present invention.

Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of this application.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described systems, devices and units may refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not implemented. On the other hand, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.

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

The functions, if implemented in the form of software functional units and sold or used as independent products, may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be embodied in the form of a software product in essence, or the part that contributes to the prior art or the part of the technical solution, and the computer software product is stored in a storage medium, including Several instructions are used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: U disk, removable hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk and other media that can store program codes .

The above are only specific implementations of the present application, but the protection scope of the present application is not limited to this. should be covered within the scope of protection of this application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

A method for active noise reduction, comprising:

Collect the sound wave vibration signal inside the human ear;

Obtain the error signal of active noise reduction according to the sound wave vibration signal inside the human ear;

determining a noise reduction signal according to the error signal of the active noise reduction, where the noise reduction signal is used to cancel the noise signal;

The noise reduction signal is played to the human ear.
The method according to claim 1, wherein the collecting the acoustic wave vibration signal inside the human ear comprises: collecting the acoustic wave vibration signal at the eardrum.
The method according to claim 2, wherein the collecting the acoustic vibration signal at the eardrum comprises:

emit light to the eardrum;

receiving light reflected from the eardrum;

Acoustic vibration signals at the eardrum are obtained according to the light reflected by the eardrum.
The method according to claim 1, wherein the collecting the acoustic vibration signal inside the human ear comprises:

Acoustic vibration signals in the external auditory canal space are collected.
The method according to claim 2 or 3, wherein the collecting the acoustic vibration signal inside the human ear further comprises:

Collect acoustic vibration signals in the external auditory canal space;

Wherein, obtaining the error signal of active noise reduction according to the sound wave vibration signal inside the human ear includes:

Obtain a first error signal according to the acoustic vibration signal at the eardrum;

Obtain a second error signal according to the acoustic vibration signal in the external auditory canal space;

The active noise reduction error signal is obtained according to the first error signal and the second error signal.
The method according to claim 4 or 5, wherein the collecting the acoustic vibration signal in the external auditory canal space comprises:

Acoustic vibration signals in the external auditory canal space are collected using a vibration sensor deployed on the earplug.
6. The method of claim 6, wherein the vibration sensor deployed on the earplug comprises an acoustic vibration acquisition unit deployed at a plurality of locations on the earplug.
The method according to claim 7, wherein the vibration sensor deployed on the earplug is a thin-film microphone annularly deployed on the earplug.
The method according to any one of claims 1 to 8, further comprising:

Collect the acoustic vibration signal of the external auditory canal;

Wherein, obtaining the error signal of active noise reduction according to the sound wave vibration signal inside the human ear includes:

The error signal of the active noise reduction is obtained according to the sound wave vibration signal inside the human ear and the sound wave vibration signal of the external auditory canal opening.
An active noise-cancelling earphone, comprising:

An error sensor is used to collect the sound wave vibration signal inside the human ear, and obtain the error signal of active noise reduction according to the sound wave vibration signal;

a controller, configured to determine a noise reduction signal according to the error signal of the active noise reduction obtained by the error sensor, where the noise reduction signal is used to cancel the noise signal;

The speaker is used to play the noise reduction signal determined by the controller to the human ear.
The earphone according to claim 10, wherein the error sensor comprises a first acoustic vibration sensor for collecting acoustic vibration signals at the eardrum.
The earphone according to claim 11, wherein the first acoustic vibration sensor is used for:

emit light to the eardrum;

receiving light reflected from the eardrum;

Acoustic vibration signals at the eardrum are obtained according to the light reflected by the eardrum.
The earphone according to claim 10, wherein the earphone comprises an earplug, and the error sensor comprises a second acoustic wave vibration sensor disposed on the earplug for collecting the acoustic wave vibration signal in the external auditory canal space.
The earphone according to claim 11 or 12, wherein the earphone comprises an earplug, and the error sensor comprises a second acoustic wave vibration sensor disposed on the earplug for collecting the acoustic wave vibration signal in the external auditory canal space;

The error sensor further includes a processing unit configured to, according to the acoustic vibration signal at the eardrum collected by the first acoustic vibration sensor and the acoustic vibration signal in the external auditory canal space collected by the second acoustic vibration sensor, Obtain the error signal of the active noise reduction.
The earphone according to claim 13 or 14, wherein the second acoustic vibration sensor comprises acoustic vibration acquisition units disposed at a plurality of positions of the earplug.
The earphone according to claim 15, wherein the second acoustic vibration sensor is a thin-film microphone annularly disposed on the earplug.
The earphone according to any one of claims 10 to 16, wherein the error sensor is further used to collect the acoustic vibration signal of the external auditory canal orifice, and be used to collect the acoustic vibration signal inside the human ear according to the acoustic vibration signal inside the human ear and the The sound wave vibration signal of the external auditory canal orifice is used to obtain the error signal of the active noise reduction.