CN116156385B

CN116156385B - Filtering method, filtering device, chip and earphone

Info

Publication number: CN116156385B
Application number: CN202310418777.9A
Authority: CN
Inventors: 吴荣贵; 王乐临; 李国梁; 王鑫山
Original assignee: Shenzhen Goodix Technology Co Ltd
Current assignee: Shenzhen Goodix Technology Co Ltd
Priority date: 2023-04-19
Filing date: 2023-04-19
Publication date: 2023-07-07
Anticipated expiration: 2043-04-19
Also published as: CN116156385A

Abstract

The application provides a filtering method, a filtering device, a chip and an earphone, and the permeation effect of the earphone can be improved. The earphone comprises an external ear microphone, and sound signals collected by the external ear microphone comprise signals of a first frequency band and signals of a second frequency band, wherein the first frequency band is lower than the second frequency band. The method comprises the following steps: processing the sound signal based on a first pass filter to obtain a first filtered signal of the sound signal, wherein the gain of the first pass filter to the signal of the first frequency band is larger than the gain of the first pass filter to the signal of the second frequency band; the sound signal is subjected to noise reduction processing, the noise-reduced sound signal is processed based on a second pass filter, a second filtering signal of the sound signal is obtained, and the gain of the second pass filter to the signal of the second frequency band is larger than that of the signal of the first frequency band; and determining a compensation signal of the earphone according to the first filtering signal and the second filtering signal.

Description

Filtering method, filtering device, chip and earphone

Technical Field

The embodiment of the application relates to the field of audio processing, and more particularly relates to a filtering method, a filtering device, a chip and an earphone.

Background

Headphones, particularly in-ear headphones, block most of the ambient sound when worn normally, and in general, the wearer of the headphones wants to hear ambient sound clearly in certain situations, and therefore the headphones need to have a pass-through mode. The through mode of the earphone can utilize the through filter to lift the sound outside the earphone, so that the outside sound is restored in the ear. The through effect of the earphone directly influences the hearing feeling of the user, so how to improve the through effect of the earphone becomes a problem to be solved.

Disclosure of Invention

The embodiment of the application provides a filtering method, a filtering device, a chip and an earphone, and can improve the permeation effect of the earphone.

In a first aspect, a filtering method is provided, applied to an earphone with a through mode, where the earphone includes an external ear microphone, and a sound signal collected by the external ear microphone includes a signal in a first frequency band and a signal in a second frequency band, where at least a part of the first frequency band is lower than at least a part of the second frequency band, and the method includes: processing the sound signal based on a first pass filter to obtain a first filtering signal of the sound signal, wherein the first pass filter is a hardware pass filter, and the gain of the first pass filter to the signal of the first frequency band in the sound signal is larger than the gain of the first pass filter to the signal of the second frequency band in the sound signal; the sound signal is subjected to noise reduction processing, the sound signal subjected to noise reduction is processed based on a second pass filter, a second filtering signal of the sound signal is obtained, the second pass filter is a software pass filter, and the gain of the second pass filter to the signal of the second frequency band in the sound signal subjected to noise reduction is larger than the gain of the second pass filter to the signal of the first frequency band in the sound signal subjected to noise reduction; and determining a compensation signal of the earphone according to the first filtering signal and the second filtering signal.

The software pass filter comprises, for example, an FIR filter or an IIR filter, and the hardware pass filter comprises, for example, an FIR filter or an IIR filter.

In one implementation, the performing noise reduction processing on the sound signal includes: acquiring a pre-estimated background noise signal; and determining the sound signal after noise reduction according to the noise signal and the sound signal.

In one implementation, the headset further includes a speaker and an in-ear microphone, the method further comprising: determining a secondary transfer function according to the audio signal output by the loudspeaker and the in-ear signal acquired by the in-ear microphone; and determining the first permeability filter according to the external ear signals collected by the external ear microphone when the earphone is in a wearing state and the signals received in the ear when the earphone is not in a wearing state.

In one implementation, the method further comprises: determining energy values of a plurality of frequency bands of the sound signal; and respectively adjusting the energy values of the plurality of frequency bands of the compensation signal according to the energy values of the plurality of frequency bands of the sound signal so that the energy values of the plurality of frequency bands of the compensation signal are smaller than or equal to the energy thresholds corresponding to the plurality of frequency bands.

In one implementation, the adjusting the energy values of the plurality of frequency bands of the compensation signal according to the energy values of the plurality of frequency bands of the sound signal includes: determining an adjustment amount corresponding to each frequency band according to the energy value of each frequency band in the plurality of frequency bands of the sound signal and the energy threshold value corresponding to each frequency band; and adjusting the energy value of each frequency band of the compensation signal according to the adjustment quantity corresponding to each frequency band.

In one implementation, the determining the adjustment amount corresponding to each frequency band according to the energy value of each frequency band in the plurality of frequency bands of the sound signal and the energy threshold value corresponding to each frequency band includes: and determining the adjustment amount corresponding to each frequency band according to the difference value between the energy value of each frequency band and the energy threshold value corresponding to each frequency band.

In one implementation, the plurality of frequency bands are frequency bands in which energy values of N frequency bands of the sound signal exceed corresponding energy thresholds, and N is a positive integer.

In one implementation, the method further comprises: determining energy values of a plurality of frequency bands of the sound signal; the first pass filter is further configured to adjust energy values of the plurality of frequency bands of the sound signal, so that the energy values of the plurality of frequency bands of the first filtered signal are less than or equal to energy thresholds corresponding to the plurality of frequency bands respectively; the second pass filter is further configured to adjust energy values of the plurality of frequency bands of the sound signal after noise reduction, so that the energy values of the plurality of frequency bands of the second filtered signal are less than or equal to energy thresholds corresponding to the plurality of frequency bands respectively.

In one implementation manner, the first pass filter is specifically configured to determine an adjustment amount corresponding to each frequency band of the plurality of frequency bands of the sound signal and an energy threshold corresponding to each frequency band, and adjust the energy value of each frequency band of the sound signal according to the adjustment amount corresponding to each frequency band; the second pass filter is specifically configured to determine an adjustment amount corresponding to each frequency band according to an energy value of each frequency band in the plurality of frequency bands of the sound signal after noise reduction and an energy threshold corresponding to each frequency band, and adjust the energy value of each frequency band of the sound signal after noise reduction according to the adjustment amount corresponding to each frequency band.

In one implementation, the first pass filter is specifically configured to determine an adjustment amount corresponding to each frequency band of the sound signal according to a difference between an energy value of the each frequency band and an energy threshold corresponding to the each frequency band; the second pass filter is specifically configured to determine an adjustment amount corresponding to each frequency band according to a difference between an energy value of each frequency band of the sound signal after noise reduction and an energy threshold corresponding to each frequency band.

In one implementation, the first frequency band is less than or equal to a preset first frequency threshold, the second frequency band is greater than or equal to a preset second frequency threshold, and the first frequency threshold and the second frequency threshold are between 2KHz and 3 KHz.

In a second aspect, a filtering device is provided, and the filtering device is applied to an earphone with a through mode, the earphone includes an external ear microphone, a sound signal collected by the external ear microphone includes a signal in a first frequency band and a signal in a second frequency band, at least part of the first frequency band is lower than at least part of the second frequency band, and the filtering device includes: the first pass filter is used for processing the sound signals to obtain first filtering signals of the sound signals, the first pass filter is a hardware pass filter, and the gain of the first pass filter to the signals of the first frequency band in the sound signals is larger than that of the first pass filter to the signals of the second frequency band in the sound signals; the processing module is used for carrying out noise reduction processing on the sound signals; the second pass filter is used for processing the sound signals subjected to noise reduction to obtain second filtering signals of the sound signals, the second pass filter is a software pass filter, and the gain of the second pass filter to the signals of the second frequency band in the sound signals subjected to noise reduction is larger than that of the second pass filter to the signals of the first frequency band in the sound signals subjected to noise reduction;

The processing module is further configured to determine a compensation signal for the earphone according to the first filtered signal and the second filtered signal.

In one implementation, the processing module is specifically configured to: acquiring a pre-estimated background noise signal; and determining the sound signal after noise reduction according to the noise signal and the sound signal.

In one implementation, the headset further includes a speaker and an in-ear microphone, and the processing module is further configured to: determining a secondary transfer function according to the audio signal output by the loudspeaker and the in-ear signal acquired by the in-ear microphone; and determining the first permeability filter according to the external ear signals collected by the external ear microphone when the earphone is in a wearing state and the received signals in the ear when the earphone is not in a wearing state.

In one implementation, the processing module is further configured to: determining energy values of a plurality of frequency bands of the sound signal; and respectively adjusting the energy values of the plurality of frequency bands of the compensation signal according to the energy values of the plurality of frequency bands of the sound signal so that the energy values of the plurality of frequency bands of the compensation signal are smaller than or equal to the energy thresholds corresponding to the plurality of frequency bands.

In one implementation, the processing module is specifically configured to: determining an adjustment amount corresponding to each frequency band according to the energy value of each frequency band in the plurality of frequency bands of the sound signal and the energy threshold value corresponding to each frequency band; and adjusting the energy value of each frequency band of the compensation signal according to the adjustment quantity corresponding to each frequency band.

In one implementation, the processing module is specifically configured to: and determining the adjustment amount corresponding to each frequency band according to the difference value between the energy value of each frequency band and the energy threshold value corresponding to each frequency band.

In one implementation, the first pass filter is further configured to adjust energy values of the plurality of frequency bands of the sound signal such that the energy values of the plurality of frequency bands of the first filtered signal are less than or equal to energy thresholds corresponding to the plurality of frequency bands respectively; the second pass filter is further configured to adjust energy values of the plurality of frequency bands of the sound signal after noise reduction, so that the energy values of the plurality of frequency bands of the second filtered signal are less than or equal to energy thresholds corresponding to the plurality of frequency bands respectively.

In a third aspect, there is provided a chip comprising a processor and a memory, the memory storing computer instructions that are invoked by the processor to cause the apparatus to implement the filtering method according to the first aspect or any implementation of the first aspect.

In a fourth aspect, there is provided an earphone having a pass-through mode, the earphone comprising: a speaker; an extra-aural microphone; an in-ear microphone; and a filter device as described in the second aspect or any implementation manner of the second aspect, or a chip as described in the third aspect.

In a fifth aspect, a filtering method is provided for an earphone having a pass-through mode, the earphone including an out-of-ear microphone, the method comprising: determining energy values of a plurality of frequency bands of the sound signal collected by the external ear microphone; and adjusting the energy values of the plurality of frequency bands of the sound signal so that the energy values of the plurality of frequency bands are smaller than or equal to the energy threshold values corresponding to the plurality of frequency bands respectively.

In one implementation, the adjusting the energy values of the plurality of frequency bands of the sound signal so that the energy values of the plurality of frequency bands are less than or equal to the energy thresholds corresponding to the plurality of frequency bands respectively includes: processing the sound signal based on a pass filter to obtain a filtered signal; wherein the adjusting the energy values of the plurality of frequency bands of the sound signal to make the energy values of the plurality of frequency bands smaller than or equal to the energy threshold value corresponding to each of the plurality of frequency bands includes: and adjusting the energy values of the plurality of frequency bands of the filtered signal so that the energy values of the plurality of frequency bands of the filtered signal are smaller than or equal to the energy threshold value corresponding to each of the plurality of frequency bands.

In one implementation, the adjusting the energy values of the plurality of frequency bands of the filtered signal so that the energy values of the plurality of frequency bands of the filtered signal are less than or equal to energy thresholds respectively corresponding to the plurality of frequency bands includes: and adjusting the energy values of the plurality of frequency bands of the filtered signal based on the pass filter or another filter outside the pass filter so that the energy values of the plurality of frequency bands of the filtered signal are smaller than or equal to the energy thresholds respectively corresponding to the plurality of frequency bands.

In one implementation, the adjusting the energy values of the plurality of frequency bands of the filtered signal includes: and determining an adjustment amount corresponding to each frequency band according to the energy value of each frequency band in the plurality of frequency bands of the sound signal and the energy threshold corresponding to each frequency band, and adjusting the energy value of each frequency band of the sound signal according to the adjustment amount corresponding to each frequency band.

In one implementation, the determining the adjustment amount corresponding to each frequency band according to the energy value of each frequency band in the plurality of frequency bands of the sound signal and the energy threshold value corresponding to each frequency band includes: and determining the adjustment amount corresponding to each frequency band according to the difference value between the energy value of each frequency band of the sound signal and the energy threshold value corresponding to each frequency band.

In one implementation, the first frequency band is less than a preset first frequency threshold, the second frequency band is greater than or equal to a preset second frequency threshold, and the first frequency threshold and the second frequency threshold are between 2KHz and 3 KHz.

In a sixth aspect, a filtering device is provided for use with an earphone having a pass-through mode, the earphone including an external ear microphone for collecting sound signals. The filtering device includes: a processing module for determining energy values of a plurality of frequency bands of the sound signal; and the filter module is used for adjusting the energy values of the plurality of frequency bands of the sound signal so that the energy values of the plurality of frequency bands are smaller than or equal to the energy threshold values corresponding to the plurality of frequency bands respectively.

In one implementation, the filter module includes a pass-through filter for: processing the sound signal to obtain a filtered signal; wherein, the penetrating filter is further used for: adjusting energy values of the plurality of frequency bands of the filtered signal so that the energy values of the plurality of frequency bands of the filtered signal are less than or equal to energy thresholds respectively corresponding to the plurality of frequency bands; alternatively, the filter module further includes another filter other than the pass filter, the another filter being configured to: and receiving the filtered signal, and adjusting the energy values of the plurality of frequency bands of the filtered signal so that the energy values of the plurality of frequency bands of the filtered signal are smaller than or equal to the energy threshold values corresponding to the plurality of frequency bands respectively.

In one implementation, the pass filter or the further filter is specifically for: and determining an adjustment amount corresponding to each frequency band according to the energy value of each frequency band in the plurality of frequency bands of the sound signal and the energy threshold corresponding to each frequency band, and adjusting the energy value of each frequency band of the compensation signal according to the adjustment amount corresponding to each frequency band.

In one implementation, the pass filter or the further filter is specifically for: and determining the adjustment amount corresponding to each frequency band according to the difference value between the energy value of each frequency band and the energy threshold value corresponding to each frequency band.

In a seventh aspect, there is provided a chip comprising a processor and a memory, the memory storing computer instructions that are invoked by the processor to cause the device to implement the filtering method according to the fifth aspect or any implementation of the fifth aspect.

An eighth aspect provides an earphone having a pass-through mode, the earphone comprising: a speaker; an extra-aural microphone; an in-ear microphone; and a filter device as described in the sixth aspect or any implementation manner of the sixth aspect, or a chip as described in the seventh aspect.

Based on the technical scheme, the sound signals collected by the external microphone are respectively processed by adopting the first transparent filter and the second transparent filter, wherein the first transparent filter is a hardware transparent filter, and the second transparent filter is a software transparent filter. In general, the earphone has stronger passive isolation to the high-frequency signal, and higher gain needs to be added to the high-frequency signal to raise, so that the background noise is mainly concentrated in the high-frequency part, therefore, the gain of the hardware pass-through filter to the middle-low frequency signal in the sound signal is larger than the gain to the high-frequency signal, and the obtained first filtering signal is mainly composed of the middle-low frequency signal; in addition, the sound signal is subjected to noise reduction processing, and the gain of the software pass filter on the high-frequency signal in the noise-reduced sound signal is larger than that of the middle-low-frequency signal, so that the obtained second filtering signal is mainly the high-frequency signal subjected to noise reduction and can be used for compensating the high-frequency signal in the first filtering signal. The first filtering signal and the second filtering signal are combined to obtain the compensating signal of the earphone, and the high-frequency signal in the second filtering signal is the signal after the noise reduction treatment, so that the problem of larger noise in the compensating signal is solved. In addition, as the sound finally heard by the human ear is formed by superposition between the sound processed by the transparent filter and the sound leaked to the human ear, when the wearer talks, the sound frequency of the human speech is concentrated at the middle-low frequency, the software transparent filter mainly processes the high-frequency signal to inhibit the middle-low frequency signal, the processing time delay of the software transparent filter to the sound signal can be greatly reduced, the time difference between the processed sound and the sound leaked to the human ear is reduced, and the sound distortion heard by the wearer is reduced.

Drawings

Fig. 1 is a schematic flow chart of a filtering method of an embodiment of the present application.

Fig. 2 is a schematic diagram of an earphone according to an embodiment of the present application.

Fig. 3 is a schematic diagram of one possible implementation of the method shown in fig. 1.

Fig. 4 is a schematic diagram of a first pass filter in a headset.

Fig. 5 is a schematic diagram of another possible implementation of the method shown in fig. 1.

Fig. 6 is a schematic diagram of another possible implementation of the method shown in fig. 1.

Fig. 7 is a schematic diagram of another possible implementation of the method shown in fig. 1.

Fig. 8 is a schematic diagram of one possible implementation of the method shown in fig. 1.

Fig. 9 is a schematic flow chart of a filtering method according to another embodiment of the present application.

Fig. 10 is a schematic block diagram of a filtering apparatus of an embodiment of the present application.

Fig. 11 is a schematic block diagram of a filtering device according to another embodiment of the present application.

Detailed Description

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

The Through mode of the earphone may use a Through (HT) filter to raise the sound outside the earphone, so as to restore the external sound in the ear. However, this simultaneously amplifies the noise floor of the internal circuitry of the earphone together, so that the played sound of the earphone carries a larger noise floor. In a quiet environment, such as an office, the microphone needs to have very small transparent sound, at this time, a large part of the input signal is the bottom noise of the circuit, and the input signal is amplified by the HT filter, so that the bottom noise is particularly obvious, the bottom noise of the circuit is reduced by the hardware circuit, and the cost is higher, and the bottom noise is difficult to eliminate.

Background noise is also one of the important factors limiting the pass-through bandwidth. Considering the problem of bottom noise, the transparent bandwidth of the earphone on the market at present is usually about 2KHz-3.5KHz, so that the transparent effect in the frequency range is ensured, if the problem of bottom noise can be solved, the larger bandwidth can be realized when the HT filter is designed, and the problem of bottom noise can be solved when the HT filter is applied to equipment such as a hearing aid, and the damage to human ears is smaller.

In general, a software pass-through manner may be used to remove mixed circuit noise from the input signal, reducing the noise below a threshold of sound audible to the human ear. Although the problem of noise floor can be solved to a certain extent by simply using the software permeation mode, the software permeation has larger time delay compared with the hardware permeation, which can cause the wearer of the earphone to hear the sound distortion of the self-speaking when speaking, because the time difference exists between the compensating human voice sent by the loudspeaker of the earphone and the human voice transmitted by bone conduction.

Therefore, the embodiment of the application provides a filtering method applied to the earphone with the through mode, and the acquired sound signals are processed by means of combination of software through and hardware through, so that the problems of noise floor and sound distortion are solved to a certain extent, and the through effect of the earphone is improved.

Fig. 1 is a schematic flow chart of a filtering method of an embodiment of the present application. The method 100 shown in fig. 1 is applicable to headphones having a pass-through mode, and may be applied to the headphones 10 shown in fig. 2, for example. The headphones described in the embodiments of the present application should be understood in a broad sense, and include not only headphones in the conventional sense shown in fig. 2, but also other types of sound players such as auxiliary or hearing devices. As shown in fig. 2, the earphone 10 includes a speaker 11, an external ear microphone 12, and an internal ear microphone 13. The out-of-ear microphone 12 may be referred to as a Feed Forward (FF) microphone or a reference microphone for collecting the sound signals transmitted from, or data outside the ear. The in-ear microphone 13 may be referred to as a Feedback (FB) microphone for collecting in-ear sound signals, or in-ear data. In the through mode, the sound signal collected by the microphone 12 outside the ear outputs a compensation signal after being processed by the through filter, and the residual signal leaking outside the earphone 10 into the human ear is superimposed, so that the human ear can hear the sound of the complete external environment. When the user wears the earphone 10 to perform a conversation with other people, the earphone 10 can be directly switched to the pass-through mode without taking off the earphone 10, so that a clear conversation with the other party is realized.

The method 100 shown in fig. 1 may be performed by a filtering device in the headset 10, for example, by a Chip in the headset 10, such as an audio codec (codec) Chip or a bluetooth audio System on a Chip (SOC) or the like. The sound signals collected by the out-of-ear microphone 12 include signals of a first frequency band and signals of a second frequency band. Wherein at least part of the first frequency bands are lower than at least part of the second frequency bands. Here, the first frequency band may be regarded as a medium-low frequency signal, and the second frequency band may be regarded as a high frequency signal. Optionally, the first frequency band is less than or equal to a preset first frequency threshold, and the second frequency band is greater than or equal to a preset second frequency threshold. The first frequency threshold is, for example, between 2KHz and 3KHz and the second frequency threshold is, for example, between 2KHz and 3 KHz.

The first frequency threshold and the second frequency threshold may be equal, for example, the first frequency threshold and the second frequency threshold are both 2.5KHz, or the first frequency threshold and the second frequency threshold are both 2.8KHz. The first frequency threshold and the second frequency threshold may also be unequal, e.g., the first frequency threshold is greater than the second frequency threshold, such as the first frequency threshold is 2.8KHz and the second frequency threshold is 2.5KHz; for another example, the first frequency threshold is less than a second frequency threshold, such as the first frequency threshold is 2.5KHz and the second frequency threshold is 2.8KHz.

As shown in fig. 1, method 100 includes some or all of the following steps.

In step 110, the sound signal collected by the extra-aural microphone 12 is processed based on the first pass filter to obtain a first filtered signal of the sound signal.

The first pass-through filter is a hardware pass-through filter, also called a hardware pass-through module, and can perform gain amplification on signals in a specific frequency band. The hardware pass filter is, for example, a hardware filter circuit. In this embodiment of the present application, the first pass filter is configured to suppress a signal in a second frequency band in the collected sound signal, that is, pass a signal in a first frequency band, where the obtained first filtered signal is mainly a signal in the first frequency band. That is, the gain of the first pass filter for the signal in the first frequency band in the sound signal is greater than the gain of the first pass filter for the signal in the second frequency band in the sound signal.

The gain of the first pass filter to the signal in the first frequency band may be greater than 1, equal to 1 or less than 1, where when the gain is greater than 1, the signal in the first frequency band is amplified, and when the gain is less than 1, the signal in the first frequency band is reduced, and when the gain is equal to 1, the signal in the first frequency band is not amplified or reduced. Similarly, the gain of the first pass filter to the signal in the second frequency band may be greater than 1, equal to 1, or less than 1, where a gain greater than 1 indicates that the signal in the second frequency band is amplified, a gain less than 1 indicates that the signal in the second frequency band is reduced, and a gain equal to 1 indicates that the signal in the second frequency band is not amplified or reduced. For example, the gain of the first pass filter for the signal in the first frequency band and the gain for the signal in the second frequency band are both greater than 1 or both less than 1; or the gain of the first pass filter on the signal of the first frequency band is larger than 1, and the gain of the first pass filter on the signal of the second frequency band is smaller than or equal to 1; or the gain of the first pass filter on the signal of the first frequency band is greater than or equal to 1, and the gain of the first pass filter on the signal of the second frequency band is less than 1.

In step 120, the noise reduction processing is performed on the sound signal collected by the external microphone 12, and the noise reduced sound signal is processed based on the second pass filter, so as to obtain a second filtered signal of the sound signal.

The second pass-through filter is a software pass-through filter, also called a software pass-through module. The software pass filter is a digital filter designed in a program, and can perform gain amplification on signals in a specific frequency band through a filtering algorithm, for example, the software pass filter can comprise a finite impulse response (Finite Impulse Response, FIR) filter or an infinite impulse response (Infinite Impulse Response, IIR) filter and the like so as to perform software filtering on sound signals after noise elimination; for another example, the hardware pass filter may include a finite impulse response (Finite Impulse Response, FIR) filter or an infinite impulse response (Infinite Impulse Response, IIR) filter, or the like, to hardware filter the sound signal collected by the out-of-ear microphone 12. In this embodiment of the present application, the second pass filter is configured to suppress a signal in a first frequency band in the collected sound signal, that is, pass a signal in a second frequency band, where the obtained second filtered signal is mainly a signal in the second frequency band. Or, the gain of the second pass filter to the signal of the second frequency band in the sound signal is larger than the gain of the second pass filter to the signal of the first frequency band in the sound signal.

The second pass filter may have a gain of greater than 1, equal to 1, or less than 1 for the signal in the first frequency band, where a gain of greater than 1 indicates that the signal in the first frequency band is amplified, and a gain of less than 1 indicates that the signal in the first frequency band is reduced, and a gain of equal to 1 indicates that the signal in the first frequency band is not amplified or reduced. Similarly, the gain of the second pass filter to the signal in the second frequency band may be greater than 1, equal to 1, or less than 1, where a gain greater than 1 indicates that the signal in the second frequency band is amplified, a gain less than 1 indicates that the signal in the second frequency band is reduced, and a gain equal to 1 indicates that the signal in the second frequency band is not amplified or reduced. For example, the gain of the second pass filter for the signal of the first frequency band and the gain for the signal of the second frequency band are both greater than 1 or both less than 1; or the gain of the second pass filter on the signal of the first frequency band is smaller than or equal to 1, and the gain of the second pass filter on the signal of the second frequency band is larger than 1; or the gain of the second pass filter on the signal of the first frequency band is smaller than 1, and the gain of the second pass filter on the signal of the second frequency band is larger than or equal to 1.

In step 130, a compensation signal for the earphone 10 is determined according to the first filtered signal output by the first pass filter and the second filtered signal output by the second pass filter.

The compensation signal is used to compensate the signal attenuated by passive isolation and is output from the speaker 11, and the compensation signal is superimposed on the residual signal leaked to the human ear to form the sound finally heard by the human ear.

In this embodiment, the first and second pass filters are used to process the sound signals collected by the microphone 12 outside the ear, where the first pass filter is a hardware pass filter, and the second pass filter is a software pass filter. In general, the earphone 10 has strong passive isolation to the high-frequency signal, and needs to add a higher gain to the high-frequency signal to raise, so that the noise is mainly concentrated in the high-frequency part, therefore, the gain of the hardware pass-through filter to the middle-low frequency signal in the sound signal is greater than the gain to the high-frequency signal, and the obtained first filtering signal is mainly the middle-low frequency signal; in addition, the sound signal is subjected to noise reduction processing, and the gain of the software pass filter on the high-frequency signal in the noise-reduced sound signal is larger than that of the middle-low-frequency signal, so that the obtained second filtering signal is mainly the high-frequency signal subjected to noise reduction and can be used for compensating the high-frequency signal in the first filtering signal. The first filtering signal and the second filtering signal are combined to obtain the compensating signal of the earphone, and the high-frequency signal in the second filtering signal is the signal after the noise reduction treatment, so that the problem of larger noise in the compensating signal is solved. In addition, as the sound finally heard by the human ear is formed by superposition between the sound processed by the transparent filter and the sound leaked to the human ear, when the wearer talks, the sound frequency of the human speech is concentrated at the middle-low frequency, the software transparent filter mainly processes the high-frequency signal to inhibit the middle-low frequency signal, the processing time delay of the software transparent filter to the sound signal can be greatly reduced, the time difference between the processed sound and the sound leaked to the human ear is reduced, and the sound distortion heard by the wearer is reduced.

It will be appreciated that the background noise signal is typically introduced by various circuitry, such as analog-to-digital converter (Analog to Digital Converter, ADC) circuitry, etc., disposed between the external ear microphone 12 and the pass-through filter, and that the earphone 10 is typically more passively isolated from the high frequency signal, requiring higher gain to be added to the high frequency signal for lifting, whether a hardware pass-through filter or a software pass-through filter is employed, resulting in a substantial concentration of the background noise in the high frequency portion. Since the noise reduction processing is performed on the sound signal collected by the external microphone 12 in step 120, the noise carried in the high-frequency signal in the second filtered signal output by the second pass filter is significantly reduced.

In this embodiment of the present application, the sound signal collected by the external ear microphone 12 refers to a sound signal received from the external ear microphone 12, i.e. a sound signal carrying a noise floor, such as the first pass filter and the second pass filter.

In one implementation, in step 120, the noise reduction process is performed on the sound signal, including: acquiring a pre-estimated background noise signal; from the noise floor signal and the sound signal collected by the external microphone 12, a noise floor reduced sound signal is determined. The noise floor signal may be obtained by means of experimental tests or the like, for example. By canceling the portion of the background noise signal carried in the sound signal by the background noise signal estimated in advance, an actual signal outside the external microphone 12 can be obtained. For example, the noise floor signal may be removed from the sound signal by adding the noise floor signal to the sound signal with the opposite sign of the noise floor signal.

For example, as shown in fig. 3, in the hardware pass-through phase, after the sound signal collected by the microphone 12 outside the ear passes through the first pass-through filter, the high-frequency signal is suppressed, and the first filtered signal mainly including the middle-low-frequency signal is output; in the software pass-through stage, the background noise estimation module outputs a background noise signal estimated in advance, the background noise signal is negative in sign, the background noise signal and the sound signal are added, so that the background noise signal carried in the sound signal can be eliminated, the background noise-reduced sound signal is obtained, after the background noise-reduced sound signal passes through the second pass-through filter, the middle-low frequency signal is restrained, and the second filtering signal mainly comprising the high-frequency signal is output. The first filtered signal and the second filtered signal are combined to obtain a compensation signal output from the speaker 11.

The background noise signal may be a fixed value; alternatively, the background noise signal may be estimated in real time based on the sound signal collected by the current external microphone 12, for example, the characteristics of the background noise signal may be collected and counted, and a reference value of the background noise signal may be preset, where the reference value may be obtained, for example, by performing frequency domain expansion on the background noise signal of the circuit, and the estimated value of the background noise signal may be obtained by adjusting the reference value according to the sound signal collected by the current external microphone 12, so as to implement real-time estimation on the background noise signal.

If only a hardware pass filter is used, as described above, since the noise floor is mainly concentrated in the high frequency part, the noise floor is amplified together when the sound signal is lifted; if only a software pass-through filter is used, the software pass-through has a larger time delay than the hardware pass-through, although the corresponding noise floor can be estimated by means of software and filtered out before the loudspeaker 11 outputs the compensation signal. The final sound heard by the human ear is formed by superposition between the compensation sound processed by the permeable filter and the residual sound leaked to the human ear, the residual sound is in physical transmission, the time delay is negligible, and if a large time delay exists between the compensation sound input into the human ear and the residual sound leaked to the human ear, the wearer can hear the sound distortion of speaking himself when speaking himself.

In the embodiment of the application, a mode of combining hardware permeation and software permeation is adopted, and because the background noise is mainly concentrated in a high-frequency part, a hardware permeation filter is utilized to inhibit high-frequency signals in the sound signals and permeate medium-low-frequency signals, so that the background noise of more high-frequency signals can be avoided; the noise floor in the sound signal is estimated (estimate noise floor), and the software pass filter is utilized to inhibit the middle-low frequency signal in the sound signal with the noise floor reduced and pass the high frequency signal, so that the software pass filter can be prevented from spending more time on the processing of the middle-low frequency signal with the concentrated human voice, the time difference between the compensating sound and the residual sound or the time delay between the compensating sound and the residual sound is reduced, and the sound distortion heard by a wearer is lightened.

Optionally, the second pass filter can be accelerated by adopting DSP hardware, and most of code implementation is written in a compilation form, so that filtering of background noise and transparent filtering can be completed in a smaller instruction period, and ultralow delay is realized.

The first filtering signal which is mainly composed of the middle-low frequency signals and is output by the hardware penetrating filter is combined with the second filtering signal which is mainly composed of the high frequency signals and is output by the software penetrating filter, and signals of the whole frequency band can be restored. Thus, the hardware pass filter and the software pass filter can compensate each other, thereby reducing the bottom noise in the compensation signal and reducing the time difference between the compensation signal and the residual signal.

In one implementation, the method 100 further includes: determining a secondary transfer function according to the audio signal output by the loudspeaker 11 and the in-ear signal collected by the in-ear microphone 13; the first pass filter is determined based on the out-of-ear signal of the earphone 10 in the worn state and the in-ear received signal in the state where the earphone 10 is not worn. It will be understood that the signal received in the ear in the state where the earphone 10 is not worn refers to a signal collected from the ear by the human ear in the state where the earphone 10 is not worn, for example, in the state where the earphone 10 is not worn by the human ear, an additional microphone may be used to collect the signal in the human ear. Whereas in determining the secondary transfer function the in-ear signal collected by the in-ear microphone 13 is typically the signal collected by the in-ear microphone 13 in the headset 10 with the headset 10 being worn.

The design of the first pass filter is specifically described in connection with fig. 4. As an example, as shown in fig. 4, the channel of the speaker 11 to the in-ear microphone 13 is a physical channel, the modeling of which is called a secondary transfer function, denoted SP, which is a transfer function representing the in-ear microphone 13 from the speaker 11, also called a secondary path transfer function. The purpose of the ventilation is to allow the wearer of the earphone 10 to hear outside sounds without being passively isolated by the earphone 10. To achieve this, it is necessary to compensate for the signal attenuated by passive isolation, and the compensation signal is output through the speaker 11. As shown in fig. 4, it is generally desirable that the signal at the in-ear microphone 13 and the signal at the out-of-ear microphone 12 coincide, and thus it is desirable that the signal played by the speaker 11 in the case of wearing the headphone 10 is superimposed with the residual signal in the ear through the secondary transmission path, as is the case with the signal received in the ear when the headphone 10 is not worn. Here, the path between the out-of-ear microphone 12 and the speaker 11 is denoted as HT. Specifically, for the same sound source, the signal acquired in the ear without wearing the headphone 10 is denoted as D, the magnitude of the residual signal acquired by the in-ear microphone 13 with wearing the headphone 10 is denoted as E, the signal acquired by the out-of-ear microphone 12 is denoted as FF, and the difference between the position of the in-ear microphone 13 and the position of the signal acquired without wearing the headphone 10 is ignored. The optimization objective of the first pass filter is ff×ht×sp+e=d, by which means a corresponding first pass filter can be obtained. In addition, the first pass filter needs to be designed to suppress the high-frequency signal, so that the frequency band amplified by hardware is concentrated at the middle-low frequency.

While it is desirable to maintain a clear sense of ambient sound when the earphone 10 is in the pass-through mode, there is often a significant amount of noise in the environment, such as whip, construction knocks, etc., the restoration of this portion of sound can cause sensory discomfort to the wearer, and excessive volume can exceed the limits expressed by the audio system, resulting in clipping problems. It is assumed that when a wearer navigates through a construction site by means of earphone voice, and falls into a dilemma, in order to hear the environmental sound, the wearer needs to turn on the through mode of the earphone, the through mode is turned on to restore all the environmental sounds, and the larger external sound causes discomfort to the ears, and the earphone in the through mode is turned off to isolate the external noise from the eardrum, so that the external noise can be effectively reduced, but the environmental sound is inconvenient to acquire.

Therefore, the application further provides an environment self-adaptive transparent scheme, the transparent quantity of the high-volume frequency band in the environment can be reduced, and the sound details of other frequency bands can be restored in the ear to the greatest extent, which is particularly important for the earphone with good passive isolation effect.

In one implementation, the method 100 further includes: acquiring energy values of a plurality of frequency bands of the sound signal acquired by the external microphone 12; and respectively adjusting the energy values of the plurality of frequency bands of the compensation signal according to the energy values of the plurality of frequency bands of the sound signal so that the energy values of the plurality of frequency bands of the compensation signal are smaller than or equal to the energy thresholds corresponding to the plurality of frequency bands.

In this embodiment, the sound signal collected by the microphone 12 outside the ear is divided into a plurality of frequency bands, or a plurality of frequency bands, and the energy values of the frequency bands are counted, and the energy values of the frequency bands in the compensation signal are respectively adjusted according to the energy values of the frequency bands in the sound signal, so that the energy values of the frequency bands of the compensation signal are smaller than or equal to the energy thresholds corresponding to the frequency bands, thereby avoiding the sense discomfort of the wearer caused by the overhigh external sound signal and realizing the self-adaptive processing of the environmental sound.

The plurality of frequency bands are, for example, frequency bands in which energy values exceed corresponding energy thresholds among N frequency bands of the sound signal, N being a positive integer. And for frequency bands for which the energy value does not exceed its corresponding energy threshold, no adjustment may be made.

Here, the energy value may be, for example, an energy peak value or an energy average value, and hereinafter, the energy peak value will be described as an example. The energy thresholds for the different frequency bands may be determined, for example, by means of experimental tests or responsivity curves. The energy thresholds corresponding to any two frequency bands in the N frequency bands may be equal or unequal.

Optionally, adjusting the energy values of the plurality of frequency bands of the compensation signal according to the energy values of the plurality of frequency bands of the sound signal includes: determining an adjustment amount corresponding to each frequency band according to the energy value of each frequency band of the sound signal and the energy threshold value corresponding to each frequency band; and adjusting the energy value of each frequency band of the compensation signal according to the corresponding adjustment quantity of each frequency band.

For example, the adjustment amount corresponding to each frequency band may be determined from a difference between an energy value of each frequency band of the plurality of frequency bands and an energy threshold value corresponding to each frequency band. The larger the difference, the larger the adjustment amount; the smaller the difference, the smaller the adjustment amount.

For example, as shown in fig. 5, after the first pass filter outputs the first filtered signal and the second pass filter outputs the second filtered signal, the first filtered signal and the second filtered signal are combined to obtain a corresponding compensation signal, and the above-mentioned adaptive processing may be performed on the compensation signal. Specifically, the frequency domain expansion may be performed according to the time domain signal collected by the external microphone 12, and the sampled effective frequency band is divided into N frequency bands by using an octave manner, for example, to count the energy peak values of the N frequency bands, and perform energy adjustment on a plurality of frequency bands in which the energy peak values exceed the corresponding energy thresholds. In the process of detecting the energy peak and estimating the adjustment amount (environment adaptive energy detection and suppression estimate), the adjustment amount corresponding to each of the plurality of frequency bands may be calculated according to a difference between the energy peak and the corresponding energy threshold of the frequency band, so that the energy value of the frequency band is adjusted according to the adjustment amount such that the energy value of the frequency band is suppressed below the corresponding energy threshold, which is also referred to as energy band suppression (subband suppression). In practical applications, the external ear microphone 12 collects the sound signals in real time, and can adjust the energy values of the frequency bands in the compensation signal in real time according to the energy values of the frequency bands in the sound signals collected in real time.

For example, the N frequency bands correspond to the N energy thresholds, and if the energy peaks of M frequency bands in the N frequency bands of the sound signal exceed the energy thresholds corresponding to the respective N frequency bands, the energy values of the M frequency bands are adjusted according to the difference between the energy peaks of the M frequency bands of the sound signal and the energy thresholds corresponding to the respective N frequency bands, for example, the adjustment amount of the i-th frequency band in the M frequency bands may be equal to the difference between the energy peak of the i-th frequency band and the energy threshold corresponding to the i-th frequency band, i is from 1 to M, and the energy value of the i-th frequency band is adjusted according to the adjustment amount of the i-th frequency band.

In the embodiment of the application, two software parts of software pass-through processing and adaptive processing of environmental sound can be combined into one software to be realized in series. For example, as shown in fig. 6, the process of detecting the energy peak and estimating the adjustment amount may be completed before the process of software-penetrating the sound signal by the second penetration filter.

In another implementation, the method 100 further includes: acquiring energy values of a plurality of frequency bands of the sound signal acquired by the external microphone 12; the first pass filter is further configured to adjust energy values of a plurality of frequency bands of the sound signal, so that the energy values of the plurality of frequency bands of the first filtered signal are less than or equal to energy thresholds corresponding to the plurality of frequency bands respectively; the second pass filter is further configured to adjust energy values of a plurality of frequency bands of the noise-reduced sound signal so that the energy values of the plurality of frequency bands of the second filtered signal are less than or equal to energy thresholds corresponding to the plurality of frequency bands.

In this embodiment, as shown in fig. 7, the first pass filter can not only suppress the high-frequency signal in the sound signal, but also adjust the energy value of each frequency band in the sound signal, so that the middle-low frequency signal is the main output in the first filtered signal, and the energy of each frequency band in the first filtered signal is less than or equal to the energy threshold value corresponding to each other. Similarly, the second pass filter can not only inhibit the middle-low frequency signals in the sound signal after noise reduction, but also adjust the energy value of each frequency band in the sound signal after noise reduction, so that the high-frequency signals are mainly output in the second filter signal, and the energy of each frequency band in the second filter signal is smaller than or equal to the energy threshold value corresponding to each frequency band.

Optionally, the first pass filter is specifically configured to determine an adjustment amount corresponding to each frequency band according to an energy value of each frequency band of the sound signal and an energy threshold corresponding to each frequency band, and adjust the energy value of each frequency band of the sound signal according to the adjustment amount corresponding to each frequency band; the second pass filter is specifically configured to determine an adjustment amount corresponding to each frequency band according to an energy value of each frequency band of the noise-reduced sound signal and an energy threshold corresponding to each frequency band, and adjust the energy value of each frequency band of the noise-reduced sound signal according to the adjustment amount corresponding to each frequency band.

For example, the first pass filter may specifically determine the adjustment amount corresponding to each frequency band according to a difference between an energy value of each frequency band of the sound signal and an energy threshold corresponding to each frequency band; the second pass filter may determine an adjustment amount corresponding to each frequency band according to a difference between an energy value of each frequency band of the noise-reduced sound signal and an energy threshold value corresponding to each frequency band.

In the above-described process of adaptive processing of the environmental sound, for example, as shown in fig. 5 or 6, after the first filtered signal and the second filtered signal are obtained through the first pass filter and the second pass filter, the energy value of the frequency band required to be band-suppressed in the combined first filtered signal and second filtered signal may be adjusted by using other filters.

Unlike fig. 5 and 6, energy band suppression can also be implemented inside the first pass filter and the second pass filter. For example, as shown in fig. 7, suppression of energy values of respective frequency bands may be directly implemented in the design of the first pass filter and the second pass filter. That is, the first and second pass filters can not only realize the pass-through of the sound signal, but also suppress the energy value of each frequency band according to the corresponding adjustment amount. Thus, the first filtering signal output by the first pass filter comprises a middle-low frequency signal after energy band suppression, and the second filtering signal output by the second pass filter comprises a high frequency signal after energy band suppression. And the energy values of the corresponding frequency bands are suppressed in the first pass filter and the second pass filter simultaneously, and an additional hardware circuit is not required to be arranged, so that the whole system structure is more compact, and the cost is reduced.

Fig. 8 shows a block flow diagram of one particular implementation of method 100. As shown in fig. 8, the pass-through stage of the environmental sound may include hardware pass-through and software pass-through, and in the hardware pass-through portion, the first pass-through filter, that is, the hardware pass-through filter is used to filter the sound signal collected by the external ear microphone 12, and output the first filtered signal mainly including the mid-low frequency signal, where the noise at the bottom of the mid-low frequency signal is small and can be ignored. In the software pass-through part, the noise signal is estimated by adopting a software mode, the noise signal is removed from the sound signal collected by the microphone 12 outside the ear, then the noise signal after the noise removal is filtered by adopting a software pass-through filter, and a second filtering signal mainly comprising a high-frequency signal is output, wherein the noise signal in the second filtering signal is basically removed. And the first filtering signal and the second filtering signal are overlapped, so that a cleaner compensation signal can be obtained.

As shown in fig. 8, in the stage of adaptive processing of the environmental sound, energy peaks of respective frequency bands are estimated, frequency bands to be energy-adjusted are determined, and an adjustment amount g, which may be in the form of a plurality of groups including adjustment amounts corresponding to a plurality of frequency bands, is determined according to a difference between a statistical value of each energy peak of the frequency bands and a corresponding energy threshold, that is, a statistical value minus the energy threshold. And outputting the adjustment quantity when the difference value is greater than or equal to 0, namely the statistical value-energy threshold value is greater than or equal to 0. The energy peak values of the frequency bands can be counted in real time and corresponding adjustment amounts can be calculated until the difference value is gradually recovered to 0. The energy of each frequency band in the compensation signal is adjusted according to the adjustment amount g, for example, the gain corresponding to each frequency band may be adjusted according to the corresponding adjustment amount. Finally, the compensating signal after the adaptive processing stage is output by the microphone.

The scheme of the self-adaptive processing of the environmental sound can be combined with the transparent scheme of the combination of the software and the hardware, and can also be independently realized.

For example, as shown in fig. 9, the embodiment of the present application further provides a filtering method 200. The method 200 may be performed by a filtering means in the headset 10, e.g. by a chip in the headset 10, such as a codec chip or a bluetooth audio SOC, etc. The earphone 10 includes an external microphone 12 for collecting sound signals. As shown in fig. 1, method 200 includes some or all of the following steps.

In step 210, energy values for a plurality of frequency bands of the sound signal are determined.

In step 220, energy values of a plurality of frequency bands of the sound signal are adjusted such that the energy values of the plurality of frequency bands are less than or equal to energy thresholds corresponding to the plurality of frequency bands, respectively.

The plurality of frequency bands may be, for example, frequency bands in which energy values of N frequency bands of the sound signal exceed corresponding energy thresholds, where N is a positive integer.

In one implementation, adjusting energy values of the plurality of frequency bands of the sound signal so that the energy values of the plurality of frequency bands are less than or equal to energy thresholds respectively corresponding to the plurality of frequency bands includes: processing the sound signal based on the pass filter to obtain a filtered signal; wherein the adjusting the energy values of the plurality of frequency bands of the sound signal to make the energy values of the plurality of frequency bands smaller than or equal to the energy threshold value corresponding to each of the plurality of frequency bands includes: and adjusting the energy values of the plurality of frequency bands of the filtered signal so that the energy values of the plurality of frequency bands of the filtered signal are smaller than or equal to the energy threshold value corresponding to each of the plurality of frequency bands.

In one implementation, adjusting energy values of the plurality of frequency bands of the filtered signal such that the energy values of the plurality of frequency bands of the filtered signal are less than or equal to respective energy thresholds of the plurality of frequency bands includes: and adjusting the energy values of the plurality of frequency bands of the filtered signal based on the pass filter or another filter outside the pass filter so that the energy values of the plurality of frequency bands of the filtered signal are smaller than or equal to the energy threshold values corresponding to the plurality of frequency bands respectively.

In one implementation, adjusting energy values of the plurality of frequency bands of the filtered signal includes: and determining an adjustment amount corresponding to each frequency band according to the energy value of each frequency band in the plurality of frequency bands of the sound signal and the energy threshold value corresponding to each frequency band, and adjusting the energy value of each frequency band of the sound signal according to the adjustment amount corresponding to each frequency band.

In one implementation, determining the adjustment amount for each frequency band of the sound signal according to the energy value for each frequency band and the energy threshold for each frequency band includes: and determining an adjustment amount corresponding to each frequency band according to a difference value between the energy value of each frequency band in the plurality of frequency bands of the sound signal and the energy threshold value corresponding to each frequency band.

It should be appreciated that specific details of the method 200 may refer to the foregoing description of the portion of the method 100 related to the adaptive processing of ambient sound, and are not repeated herein for brevity.

The present application further provides a filtering apparatus 300, where the apparatus 300 is applied to an earphone 10 having a through mode, the earphone 10 includes an external microphone 12, and a sound signal collected by the external microphone 12 includes a signal in a first frequency band and a signal in a second frequency band, and at least a part of the first frequency band is lower than at least a part of the second frequency band. For example, the first frequency band is less than or equal to a preset first frequency threshold and the second frequency band is greater than or equal to a preset second frequency threshold. The first frequency threshold and the second frequency threshold may be, for example, between 2KHz and 3 KHz.

As shown in fig. 10, the apparatus 300 includes a first pass filter 310, a processing module 320, and a second pass filter 330.

The first pass filter 310 is configured to process a sound signal to obtain a first filtered signal of the sound signal, where the first pass filter is a hardware pass filter, and a gain of the first pass filter to a signal of a first frequency band in the sound signal is greater than a gain of the first pass filter to a signal of a second frequency band in the sound signal; the processing module 320 is configured to perform noise reduction processing on the sound signal; the second pass filter 330 is configured to process the noise-reduced sound signal to obtain a second filtered signal of the sound signal, where the second pass filter is a software pass filter, and a gain of the second pass filter to a signal of a second frequency band in the noise-reduced sound signal is greater than a gain of the second pass filter to a signal of a first frequency band in the noise-reduced sound signal.

The software pass filter may be, for example, an FIR filter or an IIR filter, and the hardware pass filter may include, for example, an FIR filter or an IIR filter.

In one implementation, the processing module 320 is specifically configured to: acquiring a pre-estimated background noise signal; and determining the noise-reduced sound signal according to the noise-reduced signal and the sound signal.

In one implementation, the earphone 10 further comprises a speaker 11 and an in-ear microphone 13, and the processing module 320 is further configured to: determining a secondary transfer function according to the audio signal output by the loudspeaker 11 and the in-ear signal collected by the in-ear microphone 13; the first pass filter 310 is determined based on the external ear signal collected by the external ear microphone 12 in the worn state of the earphone 10 and the signal received in the ear in the state in which the earphone 10 is not worn.

In one implementation, the processing module 320 is further configured to: determining energy values of the plurality of frequency bands of the sound signal; and respectively adjusting the energy values of the plurality of frequency bands of the compensation signal according to the energy values of the plurality of frequency bands of the sound signal so that the energy values of the plurality of frequency bands of the compensation signal are smaller than or equal to the energy thresholds corresponding to the plurality of frequency bands respectively.

In one implementation, the processing module 320 is specifically configured to: determining an adjustment amount corresponding to each frequency band according to an energy value of each frequency band in the plurality of frequency bands of the sound signal and an energy threshold value corresponding to each frequency band; and adjusting the energy value of each frequency band of the compensation signal according to the corresponding adjustment quantity of each frequency band.

In one implementation, the processing module 320 is specifically configured to: and determining the adjustment amount corresponding to each frequency band according to the difference value between the energy value of each frequency band and the energy threshold value corresponding to each frequency band.

In one implementation, the first pass filter 310 is further configured to adjust energy values of the plurality of frequency bands of the sound signal, so that the energy values of the plurality of frequency bands of the first filtered signal are less than or equal to energy thresholds corresponding to the plurality of frequency bands respectively; the first pass filter 310 is further configured to adjust energy values of the plurality of frequency bands of the noise-reduced sound signal so that the energy values of the plurality of frequency bands of the second filtered signal are less than or equal to energy thresholds corresponding to the plurality of frequency bands.

In one implementation, the first pass filter 310 is specifically configured to determine an adjustment amount corresponding to each frequency band according to an energy value of each frequency band in the plurality of frequency bands of the sound signal and an energy threshold corresponding to each frequency band, and adjust the energy value of each frequency band of the sound signal according to the adjustment amount corresponding to each frequency band; the second pass filter 330 is specifically configured to determine an adjustment amount corresponding to each frequency band according to an energy value of each frequency band in the plurality of frequency bands of the noise-reduced sound signal and an energy threshold corresponding to each frequency band, and adjust the energy value of each frequency band of the noise-reduced sound signal according to the adjustment amount corresponding to each frequency band.

In one implementation, the first pass filter 310 is specifically configured to determine, according to a difference between an energy value of each frequency band of the sound signal and an energy threshold corresponding to each frequency band, an adjustment amount corresponding to each frequency band; the second pass filter 330 is specifically configured to determine an adjustment amount corresponding to each frequency band according to a difference between an energy value of each frequency band of the noise-reduced sound signal and an energy threshold corresponding to each frequency band.

It should be appreciated that the specific details of the filtering apparatus 300 may refer to the foregoing description of the filtering method 100, and are not repeated herein for brevity.

The present application further provides a filtering device 400, where the filtering device 400 is applied to an earphone 10 having a through mode, and the earphone 10 includes an external ear microphone 12 for collecting sound signals. As shown in fig. 11, the filtering apparatus 400 includes a processing module 410 and a filter module 420.

Wherein, the processing module 410 is configured to obtain energy values of a plurality of frequency bands of the sound signal; the filter module 420 is configured to adjust energy values of a plurality of frequency bands of the sound signal so that the energy values of the plurality of frequency bands are less than or equal to energy thresholds corresponding to the plurality of frequency bands respectively.

In one implementation, the filter module 420 includes a pass-through filter for: processing the sound signal to obtain a filtered signal; wherein, this penetrating wave filter still is used for: adjusting energy values of the plurality of frequency bands of the filtered signal so that the energy values of the plurality of frequency bands of the filtered signal are smaller than or equal to energy thresholds corresponding to the plurality of frequency bands respectively; alternatively, the filter module further comprises a further filter in addition to the pass filter, the further filter being for: and receiving the filtered signal, and adjusting the energy values of the plurality of frequency bands of the filtered signal so that the energy values of the plurality of frequency bands of the filtered signal are smaller than or equal to the energy threshold values corresponding to the plurality of frequency bands respectively.

In one implementation, the pass filter or the further filter is specifically for: and determining an adjustment amount corresponding to each frequency band according to the energy value of each frequency band in the plurality of frequency bands of the sound signal and the energy threshold value corresponding to each frequency band, and adjusting the energy value of each frequency band of the compensation signal according to the adjustment amount corresponding to each frequency band.

It should be appreciated that the specific details of the filtering apparatus 400 may refer to the foregoing description of the filtering method 200, and are not repeated herein for brevity.

The present application also provides a chip comprising a processor and a memory, including a processor and a memory, the memory storing computer instructions that the processor invokes to cause an apparatus to implement an apparatus according to the first aspect or any implementation of the first aspect. The chip may be, for example, a codec chip or a bluetooth audio SOC in the headset 10, etc.

The present application also provides an earphone 10 having a pass-through mode, the earphone 10 comprising: a speaker 11; an extra-aural microphone 12; an in-ear microphone 13; and the filtering device in any of the above embodiments, or the chip in any of the above embodiments.

It should be noted that, on the premise of no conflict, the embodiments described in the present application and/or the technical features in the embodiments may be arbitrarily combined with each other, and the technical solutions obtained after the combination should also fall into the protection scope of the present application.

The system, apparatus and method disclosed in the embodiments of the present application may be implemented in other manners. For example, some features of the method embodiments described above may be omitted or not performed. The above-described apparatus embodiments are merely illustrative, and the division of units is merely one logical function division, and there may be another division manner in actual implementation, and a plurality of units or components may be combined or may be integrated into another system. In addition, the coupling between the elements or the coupling between the elements may be direct or indirect, including electrical, mechanical, or other forms of connection.

It will be clearly understood by those skilled in the art that, for convenience and brevity of description, specific working processes and technical effects of the apparatus and device described above may refer to corresponding processes and technical effects in the foregoing method embodiments, which are not described in detail herein.

It should be understood that the specific examples in the embodiments of the present application are only for helping those skilled in the art to better understand the embodiments of the present application, and not limit the scope of the embodiments of the present application, and those skilled in the art may make various improvements and modifications based on the above embodiments, and these improvements or modifications fall within the protection scope of the present application.

The foregoing is merely 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 think about changes or substitutions within the technical scope of the present application, and the changes and substitutions are intended to 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. A method of filtering, for use with an earphone having a pass-through mode, the earphone including an out-of-ear microphone, the sound signals collected by the out-of-ear microphone including signals in a first frequency band and signals in a second frequency band, at least some of the first frequency band being lower than at least some of the second frequency band, the method comprising:

processing the sound signal based on a first pass filter to obtain a first filtering signal of the sound signal, wherein the first pass filter is a hardware pass filter, and the gain of the first pass filter to the signal of the first frequency band in the sound signal is larger than the gain of the first pass filter to the signal of the second frequency band in the sound signal;

The sound signal is subjected to noise reduction processing, the sound signal subjected to noise reduction is processed based on a second pass filter, a second filtering signal of the sound signal is obtained, the second pass filter is a software pass filter, and the gain of the second pass filter to the signal of the second frequency band in the sound signal subjected to noise reduction is larger than the gain of the second pass filter to the signal of the first frequency band in the sound signal subjected to noise reduction;

and determining a compensation signal of the earphone according to the first filtering signal and the second filtering signal.

2. The filtering method according to claim 1, wherein the noise-reducing processing of the sound signal includes:

acquiring a pre-estimated background noise signal;

and determining the sound signal after noise reduction according to the noise signal and the sound signal.

3. The filtering method according to claim 1 or 2, wherein the earphone further comprises a speaker and an in-ear microphone, the method further comprising:

determining a secondary transfer function according to the audio signal output by the loudspeaker and the in-ear signal acquired by the in-ear microphone;

And determining the first permeability filter according to the external ear signals collected by the external ear microphone when the earphone is in a wearing state and the signals received in the ear when the earphone is not in a wearing state.

4. The filtering method according to claim 1 or 2, characterized in that the method further comprises:

determining energy values of a plurality of frequency bands of the sound signal;

and respectively adjusting the energy values of the plurality of frequency bands of the compensation signal according to the energy values of the plurality of frequency bands of the sound signal so that the energy values of the plurality of frequency bands of the compensation signal are smaller than or equal to the energy thresholds corresponding to the plurality of frequency bands.

5. The filtering method according to claim 4, wherein the adjusting the energy values of the plurality of frequency bands of the compensation signal according to the energy values of the plurality of frequency bands of the sound signal includes:

determining an adjustment amount corresponding to each frequency band according to the energy value of each frequency band in the plurality of frequency bands of the sound signal and the energy threshold value corresponding to each frequency band;

and adjusting the energy value of each frequency band of the compensation signal according to the adjustment quantity corresponding to each frequency band.

6. The filtering method according to claim 5, wherein the determining the adjustment amount corresponding to each frequency band according to the energy value of each frequency band of the plurality of frequency bands of the sound signal and the energy threshold value corresponding to each frequency band includes:

and determining the adjustment amount corresponding to each frequency band according to the difference value between the energy value of each frequency band and the energy threshold value corresponding to each frequency band.

7. The filtering method according to claim 1 or 2, characterized in that the method further comprises:

the first pass filter is further configured to adjust energy values of the plurality of frequency bands of the sound signal, so that the energy values of the plurality of frequency bands of the first filtered signal are less than or equal to energy thresholds corresponding to the plurality of frequency bands respectively;

the second pass filter is further configured to adjust energy values of the plurality of frequency bands of the sound signal after noise reduction, so that the energy values of the plurality of frequency bands of the second filtered signal are less than or equal to energy thresholds corresponding to the plurality of frequency bands respectively.

8. The filtering method of claim 7, wherein,

the first pass filter is specifically configured to determine an adjustment amount corresponding to each frequency band according to an energy value of each frequency band in the plurality of frequency bands of the sound signal and an energy threshold corresponding to each frequency band, and adjust the energy value of each frequency band of the sound signal according to the adjustment amount corresponding to each frequency band;

the second pass filter is specifically configured to determine an adjustment amount corresponding to each frequency band according to an energy value of each frequency band in the plurality of frequency bands of the sound signal after noise reduction and an energy threshold corresponding to each frequency band, and adjust the energy value of each frequency band of the sound signal after noise reduction according to the adjustment amount corresponding to each frequency band.

9. The filtering method of claim 8, wherein,

the first pass filter is specifically configured to determine an adjustment amount corresponding to each frequency band according to a difference between an energy value of each frequency band of the sound signal and an energy threshold corresponding to each frequency band;

the second pass filter is specifically configured to determine an adjustment amount corresponding to each frequency band according to a difference between an energy value of each frequency band of the sound signal after noise reduction and an energy threshold corresponding to each frequency band.

10. The filtering method of claim 7, wherein the plurality of frequency bands are frequency bands in which energy values of N frequency bands of the sound signal exceed corresponding energy thresholds, and N is a positive integer.

11. The filtering method according to claim 1 or 2, wherein the first frequency band is less than or equal to a preset first frequency threshold, the second frequency band is greater than or equal to a preset second frequency threshold, and the first frequency threshold and the second frequency threshold are between 2KHz and 3 KHz.

12. A filtering device for use with an earphone having a pass-through mode, the earphone including an out-of-ear microphone, the sound signal collected by the out-of-ear microphone including a signal in a first frequency band and a signal in a second frequency band, at least a portion of the first frequency band being lower than at least a portion of the second frequency band, the filtering device comprising:

the first pass filter is used for processing the sound signals to obtain first filtering signals of the sound signals, the first pass filter is a hardware pass filter, and the gain of the first pass filter to the signals of the first frequency band in the sound signals is larger than that of the first pass filter to the signals of the second frequency band in the sound signals;

The processing module is used for carrying out noise reduction processing on the sound signals;

the second pass filter is used for processing the sound signals subjected to noise reduction to obtain second filtering signals of the sound signals, the second pass filter is a software pass filter, and the gain of the second pass filter to the signals of the second frequency band in the sound signals subjected to noise reduction is larger than that of the second pass filter to the signals of the first frequency band in the sound signals subjected to noise reduction;

13. The filtering device according to claim 12, wherein the processing module is specifically configured to:

acquiring a pre-estimated background noise signal;

14. The filtering device of claim 12 or 13, wherein the earphone further comprises a speaker and an in-ear microphone, the processing module further configured to:

15. The filtering device according to claim 12 or 13, wherein the processing module is further configured to:

16. The filtering device according to claim 15, wherein the processing module is specifically configured to:

17. The filtering device according to claim 16, wherein the processing module is specifically configured to:

18. A filter arrangement according to claim 12 or 13, characterized in that,

the first pass filter is further configured to adjust energy values of a plurality of frequency bands of the sound signal, so that the energy values of the plurality of frequency bands of the first filtered signal are less than or equal to energy thresholds corresponding to the plurality of frequency bands respectively;

the first pass filter is further configured to adjust energy values of the plurality of frequency bands of the sound signal after noise reduction, so that the energy values of the plurality of frequency bands of the second filtered signal are smaller than or equal to energy thresholds corresponding to the plurality of frequency bands.

19. The filtering apparatus of claim 18, wherein the filter is configured to filter the filter,

20. The filtering apparatus of claim 19, wherein the filter is configured to filter the filter,

21. The filtering device of claim 18, wherein the plurality of frequency bands are frequency bands in which energy values of N frequency bands of the sound signal exceed corresponding energy thresholds, N being a positive integer.

22. The filtering device of claim 12 or 13, wherein the first frequency band is less than or equal to a preset first frequency threshold, the second frequency band is greater than or equal to a preset second frequency threshold, and the first frequency threshold and the second frequency threshold are between 2KHz and 3 KHz.

23. A chip comprising a processor and a memory, the memory storing computer instructions that the processor invokes to cause the chip to implement the filtering method of any one of claims 1 to 11.

24. An earphone having a pass-through mode, the earphone comprising:

a speaker;

an extra-aural microphone;

an in-ear microphone; and

the filter device of any of the preceding claims 12 to 22, or the chip of claim 23.