CN113630681A

CN113630681A - Active noise reduction earphone

Info

Publication number: CN113630681A
Application number: CN202110897226.6A
Authority: CN
Inventors: 刘益帆; 徐银海
Original assignee: Beijing Ansheng Haolang Technology Co ltd
Current assignee: Beijing Ansheng Haolang Technology Co ltd
Priority date: 2021-08-05
Filing date: 2021-08-05
Publication date: 2021-11-09

Abstract

The application provides an earphone of making an uproar falls in initiative includes: a housing; the first microphone is positioned on the shell and used for acquiring an external noise signal; the first filter is electrically connected with the first microphone and is used for determining a noise reduction signal corresponding to the external noise signal; the loudspeaker is positioned in the inner cavity of the shell and used for playing audio signals and the noise reduction signals; the second microphone is positioned at the sound outlet of the earphone and used for acquiring an initial heartbeat sound signal; and the second filter is electrically connected with the second microphone and is used for filtering the audio signal from the initial heartbeat sound signal to obtain a target heartbeat sound signal. The technical scheme of this application can promote the SNR of target heartbeat acoustic signal to improve the rate of accuracy that heartbeat acoustic signal detected, and this application only utilizes the hardware that the earphone was always equipped with to accomplish the detection of heartbeat acoustic signal, the scheme cost is lower.

Description

Active noise reduction earphone

Technical Field

The application relates to the technical field of earphones, in particular to an active noise reduction earphone.

Background

Along with the improvement of the living standard of the material, the attention of people to the self health is continuously promoted, so that the intelligent wearable equipment with the health management function is more and more widely used. Among the health management function that intelligent wearing equipment possessed, heartbeat detection is the function that the user relatively paid attention to. The existing intelligent wearable equipment (such as a sports bracelet and a sports watch) mainly adopts a light sensation detection system to carry out heartbeat detection, the wearing requirement of the detection system on the equipment is higher, the user wrist has a nonstandard wearing posture, so that misinduction or even induction can be possibly caused, and the reliability of heartbeat detection is lower.

Disclosure of Invention

In view of the above, the present application is directed to an active noise reduction earphone for improving the accuracy of detecting a heartbeat sound signal.

The application provides an earphone of making an uproar falls in initiative includes: a housing; the first microphone is positioned on the shell and used for acquiring an external noise signal; the first filter is electrically connected with the first microphone and is used for determining a noise reduction signal corresponding to the external noise signal; the loudspeaker is positioned in the inner cavity of the shell and used for playing audio signals and the noise reduction signals; the second microphone is positioned at the sound outlet of the earphone and used for acquiring an initial heartbeat sound signal; and the second filter is electrically connected with the second microphone and is used for filtering the audio signal from the initial heartbeat sound signal to obtain a target heartbeat sound signal.

Optionally, the second filter comprises: the estimating unit is used for obtaining an estimated signal of the audio signal according to a transfer function corresponding to a transmission path from the loudspeaker to the second microphone; and the adder unit is used for subtracting the estimated signal of the audio signal from the initial heartbeat sound signal to obtain the target heartbeat sound signal.

Optionally, the number of the second microphones is at least two, and the second filter is configured to: respectively filtering corresponding audio signals from the initial heartbeat sound signals collected by each second microphone to obtain at least two heartbeat sound signals to be processed; and weighting the at least two heartbeat sound signals to be processed so as to further relatively attenuate the audio signals to obtain the target heartbeat sound signal.

Optionally, the second filter further comprises a beamformer, a main lobe direction of the beamformer pointing in the ear and a null direction pointing out of the ear, the beamformer being configured to: and inputting the heartbeat sound signals to be processed corresponding to each second microphone into the beam former respectively for weighting processing to obtain the target heartbeat sound signals.

Optionally, the headset is a half-in-ear headset.

Optionally, the second filter is further configured to: and obtaining a heartbeat sound signal waveform record and/or a heart rate index according to the target heartbeat sound signal.

Optionally, the earphone further includes an in-ear detection unit, where the in-ear detection unit is configured to determine whether the earphone is in-ear according to the target heartbeat sound signal: if the target heartbeat sound signal exists, determining that the earphone is in the ear; and if the target heartbeat sound signal does not exist, determining that the earphone is not inserted into the ear.

Optionally, the in-ear detection unit is further configured to determine the wearing tightness of the earphone according to the strength of the target heartbeat sound signal; and the earphone carries out corresponding tone quality balance adjustment on the audio signal based on the compactness.

Optionally, the second filter is further configured to: determining the estimation unit based on the audio signal, an estimated signal of the audio signal and the initial heartbeat sound signal.

Optionally, the first filter is further configured to: and determining active noise reduction parameters of the first filter based on the external noise signal, the estimation unit and the initial heartbeat sound signal.

The active noise reduction earphone provided by the embodiment of the application utilizes the microphone to collect the initial heartbeat sound signal, and then filters the audio signal played by the loudspeaker from the initial heartbeat sound signal to obtain the target heartbeat sound signal. The technical scheme of this application can promote the SNR of target heartbeat acoustic signal to improve the rate of accuracy that heartbeat acoustic signal detected, and this application embodiment only utilizes the hardware that the earphone was always equipped with to accomplish the detection of heartbeat acoustic signal, and the scheme cost is lower.

Drawings

Fig. 1 is a schematic structural diagram of an active noise reduction earphone according to an embodiment of the present application.

Fig. 2 is a schematic structural diagram of a second filter provided in the embodiment of the present application.

Fig. 3 is a schematic structural diagram of an active noise reduction earphone according to another embodiment of the present application.

Fig. 4 is a schematic structural diagram of an active noise reduction earphone according to another embodiment of the present application.

Fig. 5 is a schematic flow chart of an in-ear detection method according to an embodiment of the present application.

Fig. 6 is a schematic structural diagram of an active noise reduction earphone according to another embodiment of the present application.

Fig. 7 is a schematic flow chart of a heartbeat sound signal detection method applied to an active noise reduction earphone according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments.

It should be understood that "inner" and "outer" in this application refer to the housing of the active noise reducing headphone. The direction from the shell of the active noise reduction earphone to the internal circuit structure is inward, and the direction from the shell of the active noise reduction earphone to the internal circuit structure is outward; and not as a specific limitation on the device architecture of the present application.

It should be understood that the terms "first," "second," and the like, in this application are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Along with the improvement of the living standard of the material, the attention of people to the self health is continuously promoted, so that the intelligent wearable equipment with the health management function is more and more widely used. Among the health management function that intelligent wearing equipment possessed, heartbeat detection is the function that the user relatively paid attention to.

Current intelligent wearing equipment (for example motion bracelet, motion wrist-watch) mainly adopt light sense detecting system to carry out heartbeat detection to the motion bracelet is the example, and the sensor in the motion bracelet sends the light beam to detect the absorbed quantity of blood to the light beam that sends, thereby carry out heartbeat detection to the user according to the absorbed quantity of light. That is, after the user wears the sports bracelet, the sports bracelet can beat the light beam on the skin. When the heart pumps blood, blood vessels are full of blood, the blood tends to absorb green light and reflect red light, so the heart can generate different colors of reflected light during contraction and relaxation, and the exercise bracelet can detect the heartbeat by monitoring the reflected light. It can be seen that want to effectively use the motion bracelet to carry out the heartbeat and detect, the user need correctly wear the motion bracelet, avoids the light leak and need guarantee to wear that department's blood is unobstructed. The relatively harsh wearing requirement causes that the reliability of the detection result is lower when the existing intelligent wearable device using the light sensation detection system performs heartbeat detection. In addition, the intelligent wearable equipment using the light sensation detection system is high in cost, and the endurance of the intelligent wearable equipment can be influenced by long-time use.

In order to solve the above problems, a purpose of fast and accurate heartbeat detection is achieved, the embodiment of the application provides an active noise reduction earphone, pressure signals of periodic changes in an ear canal caused by beating of the skin of an inner ear along with a heart are collected through a microphone arranged in the earphone, a purpose of detecting heartbeat sound signals is achieved, a signal to noise ratio of the heartbeat sound signals collected by the microphone is improved, and therefore accuracy of heartbeat sound signal detection is improved.

The application does not limit the type of the active noise reduction earphone. For example, the active noise reduction earphone mentioned in the present application may be a wired earphone, and may also be a bluetooth earphone (e.g., True Wireless Stereo (TWS) earphone); alternatively, the earphone may be an in-ear earphone or a half-in-ear earphone. Preferably, the active noise reduction headphone of the present application may be a semi-in-ear headphone.

An active noise reduction earphone generally uses an out-of-ear microphone to collect an external noise signal and generates a corresponding noise reduction signal according to the collected noise signal, so that the noise reduction signal reaching a target region to be noise reduced has the same frequency, equal amplitude and opposite phase with the arriving noise signal, and the two signals are offset to realize noise reduction.

For the active noise reduction earphone, although the external noise signal collected by the microphone outside the ear can be filtered by the active noise reduction unit, the audio signal played by the speaker can be collected by the microphone for collecting the heartbeat sound signal in the earphone, so that the detected heartbeat sound signal is mixed with the audio signal.

Fig. 1 is a schematic structural diagram of an active noise reduction earphone according to an embodiment of the present application. As shown in fig. 1, the active noise reduction earphone 100 includes a housing 110, a first microphone 120, a speaker 130, a second microphone 140, a first filter 150, and a second filter 160.

The housing 110 may be a one-piece housing or a detachable housing. The housing 110 has an interior cavity in which various electronic components may be disposed.

A first microphone 120 may be located on the housing 110 as a reference microphone of the active noise reduction earphone for collecting an ambient noise signal. As one implementation, the first microphone 120 may be located on the housing 110 and in an inner cavity of the housing 110. If the first microphone 120 is disposed in the inner cavity of the housing 110, a microphone through hole 111 may be formed in the housing 110. The first microphone 120 corresponds to the microphone through hole 111 so that the first microphone 120 collects an external noise signal through the microphone through hole 111.

The number of the first microphones 120 is not particularly limited in the present application. In some embodiments, only one first microphone 120 may be disposed on the housing 110. In other embodiments, at least two first microphones 120 may be disposed on the housing 110.

When at least two first microphones 120 are disposed on the housing 110, each first microphone 120 may be disposed at a different position of the housing 110. Meanwhile, microphone through holes 111 corresponding to each first microphone 120 may be respectively provided at different positions of the case 110, so that each first microphone 120 collects an external noise signal through the respective corresponding microphone through hole 111.

Speaker 130 may be located in an interior cavity of housing 110. In some embodiments, the speaker 130 may be used to play audio signals, for example, when a user wears a headset to listen to music, after the audio signals in a music playing device (e.g., a mobile phone) are transmitted into the headset, the audio signals may be played through the speaker 130; alternatively, when the user wears the headset for voice call, an audio signal of the other party's speaking can be played through the speaker 130. In some embodiments, speaker 130 may also be used to play the noise reduction signal generated by first filter 150. How the first filter 150 (i.e., the noise reduction filter) generates the noise reduction signal will be described in detail later, and will not be described in detail here.

The second microphone 140 may be located in the inner cavity of the housing 110 at the position of the sound outlet of the earphone. The second microphone 140 may be used to acquire an initial heartbeat sound signal. Since other non-heartbeat sound signals may be collected by the second microphone 140 while the second microphone 140 collects heartbeat sound signals, other signals may be mixed in the initial heartbeat sound signal collected by the second microphone 140. For example, the initial heartbeat sound signal collected by the second microphone 140 may be mixed with the audio signal played by the speaker.

The number of the second microphones 140 is not particularly limited in the present application. In some embodiments, the second microphone 140 may be a microphone array, i.e. the number of second microphones 140 may be at least two.

The first filter 150 may be electrically connected to the first microphone 120. After receiving the external noise signal collected by the first microphone 120, the first filter 150 may generate a corresponding noise reduction signal according to the external noise signal, and then play the noise reduction signal through the speaker 130.

The second filter 160 may be electrically connected with the second microphone 140. The second filter 160 may receive the audio signal played by the speaker 130 and the initial heartbeat sound signal collected by the second microphone 140. After receiving the audio signal and the initial heartbeat sound signal, the second filter 160 may filter the audio signal from the initial heartbeat sound signal to obtain the target heartbeat sound signal.

The type and structure of the second filter 160 are not particularly limited in this application. For example, the second filter 160 may employ a band pass filter to filter out the audio signal in the initial heartbeat sound signal. Further, in designing the band-pass filter, the cutoff frequency of the band-pass filter may be designed based on the frequency range of the heartbeat sound signal.

Fig. 2 is a schematic structural diagram of a second filter provided in an embodiment of the present application. As shown in fig. 2, the second filter 160 may include an estimation unit 161 and an adder unit 162.

Since the audio signal played by the speaker will change along with the propagation path during the propagation process when entering the human ear, in order to more accurately calculate the audio signal played by the speaker mixed in the initial heartbeat sound signal, the estimation unit 161 may be used to simulate the corresponding estimation signal when the audio signal played by the speaker 130 reaches the position of the second microphone 140. For example, the estimation unit 161 may obtain an estimated signal of the audio signal according to a transfer function corresponding to a transmission path (referred to as a "secondary path") from the speaker 130 to the second microphone 140. I.e. the estimation unit 161 may be used to model the response of the secondary path to the amplitude, phase of the different frequency signals. From the simulation result of the estimation unit 161, an estimation signal of the audio signal can be obtained.

The adder unit 162 may be electrically connected to the estimation unit 161 for adding and/or subtracting the received signals. For example, after receiving the estimation signal of the audio signal sent by the estimation unit 161 and the initial heartbeat sound signal collected by the second microphone 140, the adder unit 162 may subtract the estimation signal of the audio signal from the initial heartbeat sound signal to obtain the target heartbeat sound signal.

After the second filter is used for filtering the audio signal from the initial heartbeat sound signal collected by the second microphone, the signal-to-noise ratio of the obtained target heartbeat sound signal can be obviously improved, so that the accuracy of heartbeat sound signal detection can be improved. Based on the method, the obtained target heart beat sound signal can be utilized to perform processing such as heart beat sound waveform recording, heart rate index statistics and the like, so that a more accurate processing result can be obtained.

In some embodiments, after obtaining the target heartbeat sound signal within a period of time, the period of the target heartbeat sound signal may be detected according to the waveform of the target heartbeat sound signal within the period of time, for example, the period of the target heartbeat sound signal may be detected by using a threshold analysis method, a fourier analysis method, or the like. After the period of the target heartbeat sound signal is detected, the heart rate can be calculated according to the period, and then the heart rate index statistics is carried out.

The present application does not limit the manner of obtaining the active noise reduction parameters of the first filter 150. In some embodiments, first filter 150 may employ fixed active noise reduction parameters for noise reduction. In determining the active noise reduction parameters, P is a transfer function between the first microphone 120 and the target area to be noise reduced, and G is a transfer function between the speaker 130 and the target area to be noise reduced. In order to achieve perfect noise reduction at the target area to be denoised, when the ambient noise signal and the denoising signal generated by the first filter 150 reach the target area to be denoised, the residual noise signal e (z) after the two cancel each other out should tend to 0, i.e. e (z) ═ x (z) · w (z) · g (z) + x (z) · p (z) → 0, then the optimal active denoising parameters of the first filter 150 are:

in the application scenario of the earphone, the target area to be denoised is actually the eardrum of the human ear. Since the position of the tympanic membrane of an actual human ear is difficult to measure, the first filter 150 is usually designed by engineering with the second microphone 140 at the position of the sound outlet hole of the earphone as the target area to be denoised.

In other embodiments, the first filter 150 may determine (determine online) active noise reduction parameters during the user usage phase. For example, during the user use stage, the active noise reduction parameters can be determined online in an adaptive control manner.

Referring to fig. 3, the active noise reduction headphone 300 may further include a first parameter determination device 351. In this embodiment, the second microphone 340 may also be used to collect the residual noise signal e (or, error signal e) in the ear with noise reduction. Utilize the second microphone 340 of setting in the position department of phonate vent, can directly detect the sound that gets into the people's ear, when there is the residual noise in the sound that gets into the people's ear, can be through adjusting the signal of making an uproar, track the processing to the residual noise to reach better noise reduction.

The first parameter determining device 351 performs adaptive iterative adjustment on the active noise reduction parameter based on the noise signal acquired by the first microphone 320 and the noise-reduced in-ear residual noise signal acquired by the second microphone 340, so as to determine the active noise reduction parameter.

In performing the adaptive iteration, an adaptive algorithm, such as a Least Mean Square (LMS) algorithm, may be employed.

It should be appreciated that the optimal solution of the active noise reduction parameters obtained by the adaptive iteration should also converge to

Due to different wearing habits of different users or the influence of inherent errors of filter system parameters, after the estimation signal of the audio signal is subtracted from the initial heartbeat sound signal, the signal-to-noise ratio in the obtained target heartbeat sound signal is greatly improved, but partial audio signals can still be mixed.

Therefore, in the embodiment of the present application, when there are at least two second microphones, the second filter may filter out a corresponding audio signal from the initial heartbeat sound signal collected by each second microphone, so as to obtain at least two heartbeat sound signals to be processed, where each heartbeat sound signal to be processed may still be mixed with a part of the audio signal. After obtaining the heartbeat sound signals to be processed, the second filter may perform weighting processing on the heartbeat sound signals to be processed, so as to further relatively attenuate the audio signals mixed in the heartbeat sound signals to be processed, and obtain the target heartbeat signal.

In the present application, relatively attenuating the audio signal mixed in the heartbeat sound signal to be processed may refer to enhancing the heartbeat sound signal in the heartbeat sound signal to be processed to relatively attenuate the audio signal mixed in the heartbeat sound signal to be processed; it may also refer to attenuating (or suppressing) the audio signal in the heartbeat acoustic signal to be processed.

As an implementation, a beamformer may be used to perform weighting processing on the heartbeat acoustic signals to be processed. As shown in fig. 4, fig. 4 is a schematic structural diagram of an active noise reduction earphone according to an embodiment of the present application. In this embodiment, the active noise reducing headphone 400 may include a housing 410, a first microphone 420, a speaker 430,

second microphones

441 and 442, a first filter 450, and a second filter 460. Wherein the second filter 460 may further comprise a beamformer 463.

The beamformer 463 may distinguish between signals from different directions, extract (or enhance) signals from certain directions, and remove (or suppress) interfering signals from other directions, thereby performing filtering in the spatial domain.

In the present application, the to-be-processed heartbeat sound signals corresponding to each second microphone may be input to the beamformer 463, and the input to-be-processed heartbeat sound signals may be weighted by the beamformer 463, so as to obtain the target heartbeat sound signal.

In some embodiments, the main lobe direction of the beamformer 463 may be directed in the ear and the null direction may be directed out of the ear. After the heartbeat sound signal to be processed is filtered by the beam former 463, the signal in the in-ear direction can be effectively enhanced, and the signal in the out-ear direction can be inhibited. That is, after filtering by the beamformer 463, the heartbeat sound signal from the in-ear direction can be effectively enhanced, and the audio signal played by the speaker from the out-of-ear direction can be effectively suppressed.

The beam forming method used by the beam former 463 is not limited in the present application. For example, the beamformer 463 may weight the heartbeat acoustic signal to be processed by a delay-and-sum beamforming method; alternatively, the beamformer 463 may weight the heartbeat acoustic signal to be processed by filtering and adding.

The signals to be processed are weighted by the beam former, so that the signal to noise ratio of the obtained target heartbeat sound signal can be further improved, the influence caused by different wearing habits of users and inherent errors of different system parameters is eliminated, and the consistency of the heartbeat sound signal detected by the active noise reduction earphone is improved. Especially for half-in-ear earphones, because the earplug part of invading the auditory canal is not included in the structural design, the earphone does not have the capability of relatively fixing with the auditory canal, and the positions and postures of the ears of people at different users and different moments are different.

The active noise reduction earphone provided by the present application may further include an in-ear detection unit (not shown in the figure). The in-ear detection unit can judge whether the earphone is in the ear according to the obtained target heartbeat sound signal.

As an implementation manner, the steps of performing the in-ear detection by using the in-ear detection unit in the embodiment of the present application may be referred to fig. 5.

In step 510, the presence of a target heartbeat acoustic signal is detected.

In step 520, it is determined whether the earphone is in the ear. If the in-ear detection unit detects that the target heartbeat sound signal exists, determining that the earphone is in-ear; and if the in-ear detection unit detects that the target heartbeat sound signal does not exist, determining that the earphone is not in-ear.

In some embodiments, the in-ear detection unit may further determine the wearing tightness of the earphone according to the strength of the target heartbeat sound signal. Specifically, when the in-ear detection unit detects that a target heartbeat sound signal exists and the strength of the target heartbeat sound signal is greater than a certain threshold value, the wearing tightness of the earphone can be considered to be high; when the in-ear detection unit detects that the target heartbeat sound signal exists, but the strength of the target heartbeat sound signal is smaller than the threshold value, the wearing tightness of the earphone can be considered to be low.

Further, the earphone can perform corresponding tone quality equalization adjustment on the audio signal based on the wearing tightness. For example, when the wearing tightness of the earphone is high, the strength of the audio signal can be slightly reduced, and the influence of the too high strength of the audio signal on the hearing of the user is avoided; or when the wearing tightness of the earphone is low, the strength of the audio signal can be properly enhanced, and the user can normally enjoy music or normally talk; in addition, the method also comprises the step of determining the correction quantity of the current frequency response of the earphone compared with the optimal frequency response based on the current wearing tightness of the user, so that the corresponding tone quality balance adjustment is carried out on the audio signal to be played, the consistency of the optimal tone quality is ensured, and the user experience is improved.

When the tone quality of the audio signal is adjusted in a balanced manner based on the wearing tightness of the earphone, the secondary path changes along with the wearing state of the earphone by the user. Based on this, in some embodiments, the estimation unit may be adjusted in real-time based on the audio signal.

Referring to fig. 6, fig. 6 is a schematic structural diagram of an active noise reduction earphone according to an embodiment of the present application. In this embodiment, the estimation unit 661 can be determined online in an adaptive manner during the user usage phase.

As shown in fig. 6, the active noise reduction earphone 600 may include a housing 610, a first microphone 620, a speaker 630, a second microphone 640, a first filter 650, and a second filter 660.

The first filter 650 may include a first parameter determination unit 651. The second filter 660 may include an estimation unit 661 and a second parameter determination unit 662.

The second parameter determination unit 662 may determine the estimation unit 661 based on the audio signal, the estimated signal of the audio signal, and the initial heartbeat sound signal. As an implementation manner, the second parameter determining unit 662 may determine the estimating unit 661 online in an adaptive manner.

Further, after the estimation unit 661 is adaptively determined online, the active noise reduction parameter of the first filter 650 may be determined based on the estimation unit 661 determined online. As an implementation manner, the active noise reduction parameter of the first filter 650 may be determined online in an adaptive manner, that is, the active noise reduction parameter of the first filter may be determined based on the external noise signal, the estimation unit and the initial heartbeat sound signal, where the estimation unit is determined based on the audio signal, the estimation signal of the audio signal and the initial heartbeat sound signal in an adaptive manner.

The device embodiments of the present application are described above in conjunction with fig. 1-6. A heartbeat sound detection method applied to an active noise reduction earphone according to an embodiment of the present application is described below with reference to fig. 7. For specific contents of each step in the method embodiments of the present application, reference may be made to related descriptions of the apparatus embodiments of the present application, which are not described herein again.

Fig. 7 is a schematic flow chart of a heartbeat sound signal detection method applied to an active noise reduction earphone according to an embodiment of the present application. Referring to fig. 7, at step 710, an initial heartbeat acoustic signal acquired by a second microphone is acquired.

In step 720, the audio signal played by the speaker is filtered from the initial heartbeat sound signal, so as to obtain the target heartbeat sound signal.

As an implementation manner, the estimated signal of the audio signal played by the speaker may be subtracted from the initial heartbeat sound signal to obtain the target heartbeat sound signal.

In some embodiments, at least two second microphones may be adopted to collect the initial heartbeat sound signal, and the corresponding audio signals are filtered from the initial heartbeat sound signal collected by each second microphone, respectively, so as to obtain at least two heartbeat sound signals to be processed. Further, the at least two heartbeat sound signals to be processed can be weighted to further relatively attenuate the audio signal to obtain the target heartbeat sound signal.

Specifically, as an implementation manner, the at least two heartbeat sound signals to be processed may be weighted by a beamforming algorithm to obtain a target heartbeat sound signal.

The detection method for the heartbeat sound signal applied to the active noise reduction earphone can improve the signal to noise ratio of the obtained target heartbeat sound signal, so that the accuracy of heartbeat sound signal detection is improved.

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.

In the embodiments of the present application, it should be understood that the system, apparatus and method disclosed in the embodiments of the present application can be implemented in other ways. For example, the above-described embodiments of the apparatus are merely illustrative, and the division into the units as described is merely a 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. Additionally, the communication connections shown or discussed may be electrical, mechanical or otherwise.

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

1. An active noise reduction earphone, comprising:

a housing;

the first microphone is positioned on the shell and used for acquiring an external noise signal;

the first filter is electrically connected with the first microphone and is used for determining a noise reduction signal corresponding to the external noise signal;

the loudspeaker is positioned in the inner cavity of the shell and used for playing audio signals and the noise reduction signals;

the second microphone is positioned at the sound outlet of the earphone and used for acquiring an initial heartbeat sound signal;

and the second filter is electrically connected with the second microphone and is used for filtering the audio signal from the initial heartbeat sound signal to obtain a target heartbeat sound signal.

2. The headphone of claim 1, wherein the second filter comprises:

the estimating unit is used for obtaining an estimated signal of the audio signal according to a transfer function corresponding to a transmission path from the loudspeaker to the second microphone;

and the adder unit is used for subtracting the estimated signal of the audio signal from the initial heartbeat sound signal to obtain the target heartbeat sound signal.

3. The headset of claim 1, wherein the second microphones are at least two, and wherein the second filter is configured to:

respectively filtering corresponding audio signals from the initial heartbeat sound signals collected by each second microphone to obtain at least two heartbeat sound signals to be processed;

and weighting the at least two heartbeat sound signals to be processed so as to further relatively attenuate the audio signals to obtain the target heartbeat sound signal.

4. The headset of claim 3, wherein the second filter further comprises a beamformer having a main lobe direction pointing in-the-ear and a null direction pointing out-of-the-ear, the beamformer being configured to:

and inputting the heartbeat sound signals to be processed corresponding to each second microphone into the beam former respectively for weighting processing to obtain the target heartbeat sound signals.

5. The headset of claim 1, wherein the headset is a semi-in-ear headset.

6. The headset of claim 1, wherein the second filter is further configured to:

and obtaining a heartbeat sound signal waveform record and/or a heart rate index according to the target heartbeat sound signal.

7. The headset of claim 2, further comprising an in-ear detection unit,

the in-ear detection unit is used for judging whether the earphone is in the ear according to the target heartbeat sound signal: if the target heartbeat sound signal exists, determining that the earphone is in the ear; and if the target heartbeat sound signal does not exist, determining that the earphone is not inserted into the ear.

8. The earphone according to claim 7, wherein the in-ear detection unit is further configured to determine the wearing tightness of the earphone according to the strength of the target heartbeat sound signal; and the earphone carries out corresponding tone quality balance adjustment on the audio signal based on the compactness.

9. The headset of claim 8, wherein the second filter is further configured to:

determining the estimation unit based on the audio signal, an estimated signal of the audio signal and the initial heartbeat sound signal.

10. The headset of claim 9, wherein the first filter is further configured to:

and determining active noise reduction parameters of the first filter based on the external noise signal, the estimation unit and the initial heartbeat sound signal.