Active noise reduction method, system and device, earphone and program product

Abstract

The invention provides an active noise reduction method, system and device, an earphone and a program product. The method comprises the following steps: acquiring a plurality of environmental noise acquisition signals through a plurality of feed-forward microphones of the earphone; each feedforward microphone corresponds to one first path, and each environment noise acquisition signal is transmitted through one first path; identifying a target noise scene where the earphone is located according to the plurality of environmental noise acquisition signals; according to the target noise scene, controlling a filter on each first path to work with a target filtering coefficient corresponding to the target noise scene to obtain a target noise signal; the target filtering coefficients corresponding to the filters in different target noise scenes are different; controlling a loudspeaker to output a target noise signal to form a secondary sound source; and the secondary sound source is used for offsetting the environmental noise in-ear signal reaching the human ear through the second path. According to the invention, the filtering coefficients of the plurality of filters are respectively controlled in the target noise scene, and noise reduction can be carried out for different noise scenes.

Description

Technical Field

[0001] The present application belongs to the technical field of audio noise reduction, and in particular, relates to an active noise reduction method, system, device, earphone and program product. Background Art

[0002] Since in-ear and semi-in-ear headphones are uncomfortable to wear for a long time, open-ear headphones have become popular in the market in recent years due to their comfort and safety. However, compared with other types of headphones, open-ear headphones lack passive noise reduction, and it is impossible to hear music and call voices in some noisy scenes. Therefore, active noise reduction of open-ear headphones is necessary.

[0003] Traditional noise-canceling headphones are active noise-canceling headphones based on single feedforward, which have unsatisfactory noise-canceling effects and cannot cope with various usage scenarios. Summary of the invention

[0004] The embodiments of the present application provide an active noise reduction method, system, device, headphones and program product, which can solve the problem that traditional noise reduction headphones are active noise reduction headphones based on single feedforward, have unsatisfactory noise reduction effects, and cannot cope with various usage scenarios.

[0005] In a first aspect, an embodiment of the present application provides an active noise reduction method, which is applied to headphones. The method includes:

[0006] Acquire multiple environmental noise collection signals through multiple feedforward microphones of the headset; each of the feedforward microphones corresponds to a first path, and each of the environmental noise collection signals is transmitted via one of the first paths;

[0007] According to the multiple environmental noise collection signals, identifying the target noise scene in which the headset is located; the target noise scene is one of the one or more noise scenes;

[0008] According to the target noise scene, controlling each filter on the first path to operate with a target filter coefficient corresponding to the target noise scene to obtain a target noise signal; the target filter coefficients corresponding to each filter in different target noise scenes are different;

[0009] The loudspeaker is controlled to output the target noise signal to form a secondary sound source; the secondary sound source is used to cancel the ambient noise ear signal reaching the human ear through the second path.

[0010] This embodiment uses multiple feedforward microphones in the earphones to acquire multiple environmental noise collection signals in advance on the noise propagation path, and determines the target noise scene based on the multiple environmental noise collection signals, thereby adjusting the filter coefficient in a targeted manner to obtain the target noise signal, and when the environmental noise in-ear signal reaches the speaker, the target noise signal can be played through the speaker to form a secondary sound source, thereby canceling the environmental noise in-ear signal entering the human ear.

[0011] In an optional implementation of the first aspect, the method further includes:

[0012] Acquire a preset adjustment strategy, wherein the preset adjustment strategy includes a filter coefficient corresponding to each filter on the first path in each noise scene;

[0013] According to the target noise scenario, controlling the filter on each of the first paths to operate with a target filter coefficient corresponding to the target noise scenario to obtain a target noise signal includes:

[0014] The filter coefficient corresponding to each filter in the target noise scenario in the preset adjustment strategy is used as the target filter coefficient to obtain the target noise signal.

[0015] This embodiment adjusts the filter coefficients of multiple filters to target filter coefficients through a preset adjustment strategy.

[0016] In an optional implementation of the first aspect, the noise scene includes a normal noise scene, an ultra-low frequency noise enhancement scene, a sudden low frequency noise scene, and;

[0017] The filter coefficient corresponding to each filter in the target noise scenario in the preset adjustment strategy is used as the target filter coefficient, including:

[0018] When the target noise scene is a normal noise scene, the target filter coefficient of each filter is a default filter coefficient;

[0019] When the target noise scene is an ultra-low frequency noise enhancement scene, the target filter coefficient of each of the filters is a first filter coefficient, and the first filter coefficient of each of the filters is the same or different; the first filter coefficient is a filter coefficient obtained by reducing the gain of one or more second-order IIR filters in the filter whose frequency range is lower than the first frequency;

[0020] When the target noise scenario is the burst low-frequency noise scenario, the target filter coefficient of each of the filters is a second filter coefficient, and the second filter coefficient of each of the filters is the same or different; the second filter coefficient is a filter coefficient obtained by reducing the gain of one or more second-order IIR filters in the filter whose frequency range is lower than the second frequency;

[0021] When the target noise scene is the low noise scene, the target filter coefficient of each of the filters is a third filter coefficient, and the third filter coefficient of each of the filters is the same or different; the third filter coefficient is a filter coefficient obtained by reducing the gain of all the second-order IIR filters in the filter.

[0022] This embodiment can adjust the filter coefficients of multiple filters in a targeted manner for different target noise scenarios, thereby achieving a better noise reduction effect.

[0023] In an optional implementation manner of the first aspect, identifying the target noise scene in which the headset is located according to the multiple environmental noise collection signals includes:

[0024] Performing spectrum analysis, energy analysis and characteristic analysis on the multiple environmental noise collection signals;

[0025] The target noise scene in which the earphone is located is identified according to the frequency spectrum distribution, energy level and time variation characteristics of the multiple environmental noise acquisition signals.

[0026] This embodiment can accurately identify the target noise scene in which the earphone is located by analyzing the frequency spectrum, energy and characteristics of multiple environmental noise collection signals.

[0027] In an optional implementation of the first aspect, performing spectrum analysis, energy analysis, and characteristic analysis on the multiple environmental noise collection signals includes:

[0028] The multiple environmental noise signals are subjected to discrete Fourier transform to obtain multiple frequency domain signals;

[0029] Determining a plurality of spectral energy densities according to the plurality of frequency domain signals;

[0030] Determining the total energy of the multiple environmental noise collection signals according to the multiple spectrum energy densities;

[0031] Determine, according to the plurality of spectrum energy densities, a plurality of ultra-low frequency band energies less than a first frequency and a plurality of low frequency band energies less than a second frequency; the first frequency is less than the second frequency;

[0032] According to the ratio of each ultra-low frequency band energy to the total energy of the environmental noise collection signal corresponding to each ultra-low frequency band energy, a plurality of ultra-low frequency energy proportions are obtained;

[0033] Determining a plurality of low-frequency energy change rates according to the plurality of low-frequency band energies;

[0034] Determining a plurality of transient characteristics according to peak values ​​and average values ​​of the plurality of environmental noise acquisition signals;

[0035] A plurality of spectrum smoothnesses are determined according to the distribution uniformity of the plurality of spectrum energy densities of the frequency components in the entire frequency range.

[0036] In an optional implementation of the first aspect, determining the target noise scene according to the spectrum distribution, energy level and time variation characteristics of the multiple environmental noise acquisition signals includes:

[0037] Multiple or all of the multiple spectrum smoothnesses are less than a first smoothness threshold, multiple or all of the total energies of the multiple environmental noise acquisition signals are within a first energy range, and the current scene is determined to be a normal noise scene;

[0038] Multiple or all of the multiple ultra-low frequency band energies are greater than the second energy threshold, and multiple or all of the multiple ultra-low frequency energy proportions are greater than the first proportion threshold, and the current scene is determined as an ultra-low frequency noise enhancement scene;

[0039] If multiple or all of the multiple low-frequency energy change rates are greater than a first change rate threshold, and multiple or all of the multiple transient characteristics are greater than a first transient characteristic threshold, the current scene is determined to be a sudden low-frequency noise scene;

[0040] The total energy of the multiple environmental noise collection signals is less than a third energy threshold, and the current scene is determined to be a low-noise scene.

[0041] This embodiment can analyze the target noise scene in which the earphone is currently located through the above calculation logic.

[0042] In a second aspect, an embodiment of the present application provides an active noise reduction system, including headphones and a test device;

[0043] The test equipment is used to:

[0044] Performing system identification on multiple adjustment systems in the earphones through frequency sweep signals to determine the filter coefficient of each filter in the earphones; any of the adjustment systems includes any feedforward microphone and a speaker;

[0045] The earphone is used to execute the method as described in any one of the first aspects

[0046] In a third aspect, an embodiment of the present application provides an active noise reduction device, comprising:

[0047] An acquisition module, configured to acquire a plurality of environmental noise acquisition signals through a plurality of feedforward microphones of the headset; each of the feedforward microphones corresponds to a first path, and each of the environmental noise acquisition signals is transmitted via a first path;

[0048] an identification module, configured to identify a target noise scene in which the headset is located according to the plurality of environmental noise collection signals; the target noise scene being one of the one or more noise scenes;

[0049] A control module, configured to control the filter on each of the first paths to operate with a target filter coefficient corresponding to the target noise scene according to the target noise scene, so as to obtain a target noise signal; wherein the target filter coefficients corresponding to each of the filters in different target noise scenes are different;

[0050] The playing module is used to control the loudspeaker to output the target noise signal to form a secondary sound source; the secondary sound source is used to offset the ambient noise ear signal reaching the human ear through the second path.

[0051] In a fourth aspect, an embodiment of the present application provides a headset, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method described in any one of the first aspects when executing the computer program.

[0052] In an optional implementation of the fourth aspect, the earphone is an open earphone, comprising a body, an ear hook and a pivot connection part; the multiple feedforward microphones are located on one or more of the body, the ear hook and the pivot connection part.

[0053] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method as described in any one of the first aspects is implemented.

[0054] In a sixth aspect, an embodiment of the present application provides a computer program product, which, when executed on an earphone, enables the earphone to execute any one of the methods described in the first aspect.

[0055] It can be understood that the beneficial effects of the second to sixth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0056] Compared with the prior art, the embodiments of the present application have the following beneficial effects: the embodiments of the present application design multiple feedforward microphones in the earphones, so that at least one of the multiple feedforward microphones can obtain multiple ambient noise collection signals in advance of the speaker on the noise propagation path, determine the current target noise scene according to the multiple ambient noise collection signals, and control the filter coefficients of multiple filters according to the target noise scene to obtain the target noise signal, and when the ambient noise in-ear signal reaches the speaker, the speaker plays the target noise signal to generate a secondary sound source, whose amplitude is equivalent to the amplitude of the ambient noise in-ear signal, the phase is opposite, and the frequency is equivalent, thereby offsetting or partially offsetting the ambient noise in-ear signal reaching the human ear, thereby completing noise reduction for different noise scenes. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0058] Figure 1 A top view of a conventional single feed-forward microphone active noise reduction headset worn on a person's head is shown;

[0059] Figure 2 A front view of an open-type earphone disclosed in an embodiment of the present application is shown;

[0060] Figure 3 A rear view of an open-type earphone disclosed in an embodiment of the present application is shown;

[0061] Figure 4 A schematic diagram of the process of the active noise reduction method disclosed in the embodiment of the present application is shown;

[0062] Figure 5 A schematic diagram showing the principle of the active noise reduction method provided in an embodiment of the present application is shown;

[0063] Figure 6 A top view showing a pair of headphones according to an embodiment of the present application being worn on a person's head;

[0064] Figure 7 A schematic diagram showing the principle of an active noise reduction system provided in an embodiment of the present application is shown;

[0065] Figure 8 A schematic structural diagram of an active noise reduction device provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0066] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0067] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0068] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0069] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0070] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0071] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0072] Figure 1 A top view of a conventional single feedforward microphone active noise reduction headset worn on a person's head is shown. Figure 1It can be seen from the figure that the traditional single feedforward microphone 110 active noise reduction headset can actively reduce noise in a narrow direction and has a narrow frequency band (i.e., the frequency range of the ambient noise signal). In addition, the noise reduction effect of traditional noise reduction headsets is often greatly reduced in the face of complex and changing scenes.

[0073] To this end, an embodiment of the present application provides an active noise reduction method, which can be applied to various types of headphones. For example, according to the wearing method, it can include open-type headphones, earbud headphones, head-mounted headphones, in-ear headphones, semi-in-ear headphones, neck-hanging headphones, bone conduction headphones, ear clip headphones, headphones with feedback microphones, etc.

[0074] Figure 2 A front view of an open-type earphone disclosed in an embodiment of the present application is shown. Figure 3 A rear view of an open-type headset disclosed in an embodiment of the present application is shown. The open-type headset includes a body 170, an ear hook 190 and a shaft connection portion 180, and the ear hook is rotatably mounted on the body via the shaft connection portion. A speaker 120, a control circuit, a first feedforward microphone 130, a second feedforward microphone 140, a first filter 150, a second filter 160, etc. are installed in the body. The distance between one end of the first feedforward microphone for collecting sound and one end of the second feedforward microphone for collecting sound is greater than a preset distance. It is easy to understand that the preset distance between the first feedforward microphone and the second feedforward microphone is different for headphones of different models and types. When the user is in an upright state and the earphones are worn on the user's ears, the speaker is located on the side of the main body close to the user's eardrum, the first feedforward microphone and the second feedforward microphone are both located on the side of the main body away from the user's eardrum, and the first feedforward microphone is positioned as far forward as possible (the front refers to the front when the user is in an upright state), and the second feedforward microphone is positioned as far back as possible (the back refers to the back when the user is in an upright state). As a result, the two feedforward microphones can obtain ambient noise collection signals from different directions in advance at the front and back positions relative to the speaker and process them through filters, thereby suppressing the ambient noise in-ear signals entering the human ear.

[0075] It is easy to understand that the first feedforward microphone and the second feedforward microphone can be located on the body, or on one or more of the body, the ear hook, and the shaft connection portion. For example, the first feedforward microphone can be installed on the body, and the second feedforward microphone can be installed on the ear hook; or, the first feedforward microphone can be installed on the shaft connection portion, and the second feedforward microphone can be installed on the ear hook; or, the first feedforward microphone can be installed on the body, and the second feedforward microphone can be installed on the shaft connection portion; or, both the first feedforward microphone and the second feedforward microphone can be installed on the ear hook.

[0076] Figure 4The schematic diagram of the active noise reduction method disclosed in the embodiment of the present application is shown. The ambient noise signal reaches the human ear through three paths. The first feedforward microphone and the first filter are located on the first reference path, and the second feedforward microphone and the second filter are located on the second reference path. The first ambient noise collection signal collected by the first feedforward microphone is filtered by the first filter, and the second ambient noise collection signal collected by the second feedforward microphone is filtered by the second filter. After the two filtered ambient noise signals are superimposed, a secondary sound source is formed through a loudspeaker (located on the secondary path); the ambient noise in-ear signal is directly transmitted through the second path (i.e., Figure 4 No matter the noise is transmitted from the front, back or side, one of the two feedforward microphones can filter the collected ambient noise signal before the speaker, and play the secondary sound source when the ambient noise signal reaches the speaker, so as to suppress or cancel the ambient noise signal.

[0077] Currently, neither open-type headphones (without passive noise reduction function) nor in-ear headphones (with passive noise reduction function) can prevent the ambient noise signal from entering the human ear.

[0078] Figure 5 A schematic flow chart of an active noise reduction method disclosed in an embodiment of the present application is shown. The method is applied to headphones and includes S210-S240.

[0079] S210: Acquire multiple environmental noise collection signals through multiple feedforward microphones of the headset; each feedforward microphone corresponds to a first path, and each environmental noise collection signal is transmitted via a first path.

[0080] It should be noted that the multiple feedforward microphones refer to more than two (including two) feedforward microphones, and each feedforward microphone corresponds to an environmental noise collection signal.

[0081] Exemplarily, the multiple feedforward microphones include a first feedforward microphone and a second feedforward microphone, the first path includes a first reference path and a second reference path, and the multiple ambient noise collection signals include a first ambient noise collection signal and a second ambient noise collection signal, then S210 is: obtaining the first ambient noise collection signal through the first feedforward microphone of the headset, and obtaining the second ambient noise collection signal through the second feedforward microphone. The first feedforward microphone corresponds to the first reference path, the second feedforward microphone corresponds to the second reference path, the first ambient noise collection signal is transmitted via the first reference path, and the second ambient noise collection signal is transmitted via the second reference path.

[0082] S220: Identify a target noise scene in which the earphone is located according to the multiple environmental noise collection signals; the target noise scene is one of the one or more noise scenes.

[0083] Optionally, the noise scenarios include: normal noise scenarios, ultra-low frequency noise enhancement scenarios, sudden low frequency noise scenarios, and low noise scenarios.

[0084] Taking two feedforward microphones as an example, two environmental noise collection signals are corresponding, namely a first environmental noise collection signal and a second environmental noise collection signal. Then S220 is: identifying the target noise scene where the headset is located according to the first environmental noise collection signal and the second environmental noise collection signal.

[0085] S230: According to the target noise scene, control the filter on each first path to operate with a target filter coefficient corresponding to the target noise scene to obtain a target noise signal; the target filter coefficient corresponding to each filter in different target noise scenes is different.

[0086] It should be noted that the feedforward microphone and the filter in the earphone are in one-to-one correspondence, and each first path has a feedforward microphone and a filter (the filter can be a series connection of multiple second-order IIR filters of different frequency bands).

[0087] Taking two feedforward microphones as an example, there are two corresponding filters, namely the first filter and the second filter. Then S230 is: according to the target noise scene, control the first filter on the first reference path to operate with the first target filter coefficient and control the second filter on the second reference path to operate with the second target filter coefficient to obtain the target noise signal; the first target filter coefficient and the second target filter coefficient are the filter coefficients corresponding to the target noise scene, respectively, and the first target filter coefficient and the second target filter coefficient corresponding to the first filter and the second filter in different target noise scenes are different.

[0088] Optionally, after the target noise scene is determined, a preset adjustment strategy can be obtained first, and then the current filter coefficient / default filter coefficient can be adjusted to the first target filter coefficient and the second target filter coefficient according to the preset adjustment strategy; or, the current filter coefficient can be switched to the corresponding first target filter coefficient and the second target filter coefficient according to the correspondence between the target noise scene and the first target filter coefficient and the second target filter coefficient stored in the earphone.

[0089] S240: Control the speaker to output the target noise signal to form a secondary sound source; the secondary sound source is used to cancel the ambient noise in-ear signal reaching the human ear through the second path.

[0090] The target noise signal is an electrical signal, the secondary sound source is a sound wave signal, and the ambient noise input signal reaching the human ear is also a sound wave signal.

[0091] When the active noise reduction function is turned on in current noise reduction headphones, users often hear rustling or buzzing sounds. There are many reasons for this phenomenon, such as: (1) Low-frequency noise (such as engine noise, traffic noise, etc.) usually has a large sound pressure level and a long wavelength, which makes the energy of low-frequency noise concentrated when propagating in space, resulting in a high intensity of the ambient noise signal received by the feedforward microphone. (2) The frequency response of many feedforward microphones in the low frequency band may not be flat enough, or they may be more sensitive to low-frequency signals, which will cause the acquisition results of low-frequency noise signals to be high. (3) The design and construction of the feedforward microphone may make it more susceptible to physical effects at low frequencies, such as air pressure changes or vibrations, which will cause signal distortion or saturation. (4) Low-frequency noise often resonates in the environment, especially in closed or semi-enclosed spaces, which will cause noise of certain frequencies to be amplified, resulting in a high ambient noise signal collected by the feedforward microphone.

[0092] In this embodiment, the two filters (the first filter and the second filter) have different adjustment strategies for different noise scenarios, specifically, adjusting the filter coefficients of the two filters, the filter coefficients including gain, weight, etc., wherein the weights include the first weight of the first filter and the second weight of the second filter, and the sum of the first weight and the second weight is 1. Optionally, the first weight and the second weight can be preset fixed values, or can be adjusted specifically in the face of different scenarios. The target noise signal is formed by superimposing the first noise reduction signal obtained by the first filter operating with the first target filter coefficient and the second noise reduction signal obtained by the second filter operating with the second target filter coefficient. By adjusting the filter coefficient, the rustling or buzzing sound emitted by the headphones can be greatly reduced.

[0093] See also Figure 1 The traditional single feedforward microphone has a small angle range for suppressing ambient noise. This is because the single feedforward microphone is restricted by the installation position. Ambient noise signals beyond its collection range will reach the human ear at the same time or faster, causing the headphones to not have time to process these ambient noise signals. The previous method was to predict the amplitude, phase and frequency of the noise, and then process the predicted values ​​to form a secondary sound source to offset the ambient noise in-ear signal. However, the amplitude and frequency of the secondary sound source may not match the ambient noise in-ear signal entering the human ear, and the phase may not be opposite, resulting in poor noise reduction effect of single feedforward microphone noise reduction headphones.

[0094] Figure 6A top view of a pair of headphones according to an embodiment of the present application being worn on a person's head is shown, wherein the first feedforward microphone can collect a first ambient noise collection signal from the front and sides, and the second feedforward microphone can collect a second ambient noise collection signal from the back and sides. By providing two feedforward microphones and corresponding filters, the embodiment of the present application can suppress a wider range of ambient noise in-ear signals entering the ear. Before the ambient noise in-ear signal reaches the speaker, the two feedforward microphones can first process the collected ambient noise collection signal through two filters, and then the speaker generates a secondary sound source, and then when the ambient noise in-ear signal reaches the speaker, the secondary sound source is played, so that the phase of the secondary sound source can be opposite to the phase of the ambient noise in-ear signal, the amplitude is equivalent, and the frequency is equivalent, thereby improving the noise reduction effect.

[0095] The embodiment of the present application designs multiple feedforward microphones in the earphones, at least one of the multiple feedforward microphones can obtain multiple environmental noise collection signals in advance of the speaker on the noise propagation path, determine the current target noise scene according to the multiple environmental noise collection signals, and control the filter coefficients of multiple filters according to the target noise scene to obtain the target noise signal. When the environmental noise in-ear signal reaches the speaker, the speaker plays the target noise signal to generate a secondary sound source, whose amplitude is equivalent to the amplitude of the environmental noise in-ear signal, the phase is opposite, and the frequency is equivalent, thereby offsetting or partially offsetting the environmental noise in-ear signal reaching the human ear, thereby completing noise reduction for different noise scenes.

[0096] As an optional implementation, in S120, the target noise scene in which the earphone is located is identified according to the multiple environmental noise collection signals, including S121-S122.

[0097] S121: Perform spectrum analysis, energy analysis, and characteristic analysis on multiple environmental noise collection signals.

[0098] S122: Identify a target noise scene in which the earphone is located according to frequency spectrum distribution, energy level, and time variation characteristics of the plurality of environmental noise acquisition signals.

[0099] As an optional implementation, taking two feedforward microphones as an example, the two feedforward microphones correspond to two ambient noise collection signals, namely the first ambient noise collection signal and the second ambient noise collection signal, then S121: perform spectrum analysis, energy analysis and characteristic analysis on multiple ambient noise collection signals, including S1211-S1218.

[0100] S1211: Perform discrete Fourier transformation on the first environmental noise collection signal to obtain a first frequency domain signal; perform discrete Fourier transformation on the second environmental noise collection signal to obtain a second frequency domain signal.

[0101] S1212: Determine a first spectrum energy density according to the first frequency domain signal; and determine a second spectrum energy density according to the second frequency domain signal.

[0102] The first environmental noise acquisition signal x collected by the first feedforward microphone f (t) is expressed as:

[0103] x f (t) = n f (t)+v(t)

[0104] in:

[0105] n f (t): the first environmental noise acquisition signal; v(t): the background noise of the first feedforward microphone (assumed to be Gaussian white noise with a mean of 0 and a variance of ).

[0106] The second environmental noise acquisition signal x collected by the second feedforward microphone b (t) is expressed as:

[0107] x b (t) = n b (t)+v(t)

[0108] in:

[0109] n b (t): the second environmental noise acquisition signal; v(t): the background noise of the second feedforward microphone (assumed to be Gaussian white noise with a mean of 0 and a variance of ).

[0110] Conversion and spectrum analysis of the first environmental noise acquisition signal and the second environmental noise acquisition signal:

[0111] The acquired time domain signal x f (t) Obtain the first frequency domain signal X through discrete Fourier transform (DFT) f (F):

[0112]

[0113] The acquired time domain signal x b (t) Obtain the second frequency domain signal X through discrete Fourier transform (DFT) b (f):

[0114]

[0115] The first spectrum energy density P f(f) is expressed as:

[0116] P f (f) = |X f (f)| 2

[0117] The second spectrum energy density P b (f) is expressed as:

[0118] P b (f) = |X b (f)| 2

[0119] S1213: Determine the total energy of the first environmental noise collection signal according to the first spectrum energy density; determine the total energy of the second environmental noise collection signal according to the second spectrum energy density.

[0120] S1214: Determine, based on the first spectrum energy density, a first ultra-low frequency band energy that is less than the first frequency and a first low frequency band energy that is less than the second frequency; determine, based on the second spectrum energy density, a second ultra-low frequency band energy that is less than the first frequency and a second low frequency band energy that is less than the second frequency; the first frequency is less than the second frequency.

[0121] S1215: Obtain a first ultra-low frequency energy ratio according to a ratio of the first ultra-low frequency band energy to the total energy of the first environmental noise collection signal; obtain a second ultra-low frequency energy ratio according to a ratio of the second ultra-low frequency band energy to the total energy of the second environmental noise collection signal.

[0122] Energy analysis of the first environmental noise acquisition signal and the second environmental noise acquisition signal:

[0123] a) Total energy:

[0124] Calculate the total energy E of the ambient noise signal total :

[0125]

[0126] where f max It is half the system sampling frequency (Nyquist frequency).

[0127] For the first environmental noise acquisition signal and the second environmental noise acquisition signal:

[0128] The total energy E of the first environmental noise acquisition signal total,f :

[0129]

[0130] The second environmental noise acquisition signal energy E total,b :

[0131]

[0132] b) Frequency band energy:

[0133] Set a specific frequency band range [f1,f2] and calculate the energy E of the corresponding frequency band [f1,f2] :

[0134]

[0135] For the desired frequency band:

[0136] Ultra-low frequency (i.e., the first frequency, illustratively, the first frequency <80 Hz):

[0137] E ul =∫0 80 P(f)df

[0138] The first ultra-low frequency band energy E ul,f It is expressed as:

[0139] E ul,f =∫0 80 P f (f)df

[0140] The second ultra-low frequency band energy E ul,b It is expressed as:

[0141] E ul,b =∫0 80 P b (f)df

[0142] Low frequency (i.e., the second frequency, illustratively, the second frequency <250 Hz):

[0143] E lf =∫0 250 P(f)df

[0144] The energy of the first low frequency band E lf,f It is expressed as:

[0145] E lf,f =∫0 250 P f (f)df

[0146] The energy of the second low frequency band E lf,b It is expressed as:

[0147] E lf,b =∫0 250 P b (f)df

[0148] c) Energy ratio:

[0149] Calculate the ratio of frequency band energy to total energy:

[0150]

[0151] For the desired frequency band:

[0152] Ultra-low frequency (<80Hz):

[0153]

[0154] The first ultra-low frequency energy ratio R ul,f It is expressed as:

[0155]

[0156] The first ultra-low frequency energy ratio R ul,b It is expressed as:

[0157]

[0158] S1216: Determine a first low-frequency energy change rate according to the first low-frequency band energy at the current moment and the first low-frequency band energy at the previous moment; determine a second low-frequency energy change rate according to the second low-frequency band energy at the current moment and the second low-frequency band energy at the previous moment.

[0159] S1217: Determine a first transient characteristic according to a peak value and an average value in the first environmental noise collection signal; determine a second transient characteristic according to a peak value and an average value in the second environmental noise collection signal.

[0160] Dynamic characteristics analysis:

[0161] Dynamic characteristics are used to capture the changes of signals over time, including the rate of energy change and transient characteristics.

[0162] a) Low frequency energy change rate:

[0163] Assume that the sampling time interval is Δt and the energy change rate is:

[0164]

[0165] Where E(t) is the energy at the current moment, and E(t-Δt) is the energy at the previous moment.

[0166] ·The first low-frequency energy change rate ΔE f (t) is expressed as:

[0167]

[0168] The second low-frequency energy change rate ΔE b (t) is expressed as:

[0169]

[0170] b) Transient characteristics:

[0171] The transient characteristic is used to describe the sudden increase of signal amplitude in a short period of time, and is expressed by the ratio of peak value to average value (peak-to-average ratio κ):

[0172]

[0173] in:

[0174] T: Time window for transient analysis.

[0175] x(t): collected time domain signal.

[0176] max: signal peak value within the window.

[0177] mean: The signal mean within the window.

[0178] First transient characteristic κ f (t) is expressed as:

[0179]

[0180] Second transient characteristic κ b (t) is expressed as:

[0181]

[0182] S1218: Determine a first spectrum smoothness according to a distribution uniformity of a first spectrum energy density of each frequency component in the entire frequency range; determine a second spectrum smoothness according to a distribution uniformity of a second spectrum energy density of each frequency component in the entire frequency range.

[0183] Spectral smoothness analysis:

[0184] Spectral smoothness is used to describe the uniformity of the signal spectrum distribution and is often defined by the standard deviation:

[0185]

[0186] The first spectral smoothness σ f,f It is expressed as:

[0187]

[0188] The first spectral smoothness σ f,b It is expressed as:

[0189]

[0190] As some optional implementations, taking two feedforward microphones as an example, S122: identifying the target noise scene in which the earphone is located according to the spectrum distribution, energy level and time variation characteristics of multiple environmental noise acquisition signals, including S1221-S1224.

[0191] S1221: The first spectrum smoothness is less than the first smoothness threshold corresponding to the first reference path, and the total energy of the first environmental noise acquisition signal is within the first energy range corresponding to the first reference path. The second spectrum smoothness is less than the first smoothness threshold corresponding to the second reference path, and the total energy of the second environmental noise acquisition signal is within the first energy range corresponding to the second reference path. The current scene is determined to be a normal noise scene.

[0192] For example, in a normal noise scenario, the characteristics are described as follows:

[0193] The spectrum distribution of the environmental noise signal is relatively uniform, there is no abnormal enhancement of the low-frequency components and the mid-to-high-frequency components, and the total noise energy level is within the normal range.

[0194] In normal noise scenarios, the spectral smoothness and total energy judgment criteria of the first reference path are:

[0195] a) First spectrum smoothness σ f,f satisfy:

[0196] σ f,f <∈ f,1

[0197] Among them, ∈ f,1 Indicates a first smoothness threshold corresponding to the first reference path.

[0198] b) Total energy E of the first environmental noise acquisition signal total,f satisfy:

[0199] η f,min ≤E total,f ≤η f,max

[0200] Among them, η f,min and η f,max The first energy range between them is the first reference path.

[0201] In normal noise scenarios, the spectrum smoothness and total energy judgment criteria of the second reference path are:

[0202] a) Second spectrum smoothness σ f,b satisfy:

[0203] σ f,b <∈ b,1

[0204] Among them, ∈ b,1Represents the first smoothness threshold corresponding to the second reference path. f,1 With ∈ b,1 They may be the same or different, and this embodiment does not limit this.

[0205] b) Total energy level:

[0206] η b,min ≤E total,b ≤η b,max

[0207] Among them, η b,min and η b,max The first energy range corresponding to the second reference path is between η b,min With η f,min , and η b,max With η f,max , may be the same or different, and this embodiment does not limit this.

[0208] S1222: the energy of the first ultra-low frequency band is greater than the second energy threshold corresponding to the first reference path, the proportion of the first ultra-low frequency energy is greater than the first proportion threshold corresponding to the first reference path, the energy of the second ultra-low frequency band is greater than the second energy threshold corresponding to the second reference path, and the proportion of the second ultra-low frequency energy is greater than the first proportion threshold corresponding to the first reference path, and the current scene is determined as an ultra-low frequency noise enhancement scene.

[0209] Exemplarily, in the ultra-low frequency noise enhancement scenario, the characteristics are described as follows:

[0210] The energy of ultra-low frequency (<80Hz) noise is significantly enhanced, and the proportion of the total energy exceeds the threshold.

[0211] In the ultra-low frequency noise enhancement scenario, the ultra-low frequency band energy and ultra-low frequency energy ratio judgment criteria of the first reference path are:

[0212] a) Energy E of the first ultra-low frequency band ul,f satisfy:

[0213] E ul,f >η f,ul

[0214] Among them, η f,ul Indicates the second energy threshold corresponding to the first reference path.

[0215] b) The first ultra-low frequency energy ratio R ul,f satisfy:

[0216] R ul,f >β f,1

[0217] Among them, β f,1Indicates the first proportion threshold corresponding to the first reference path.

[0218] In the ultra-low frequency noise enhancement scenario, the ultra-low frequency band energy and ultra-low frequency energy ratio judgment criteria of the second reference path are:

[0219] a) Energy E of the second ultra-low frequency band ul,b satisfy:

[0220] E ul,b >η b,ul

[0221] Among them, η b,ul represents the second energy threshold corresponding to the second reference path. b,ul With η f,ul They may be the same or different, and this embodiment does not limit this.

[0222] b) The second ultra-low frequency energy ratio R ul,b satisfy:

[0223] R ul,b >β b,1

[0224] Among them, β b,1 Indicates the first proportion threshold corresponding to the second reference path. b,1 With β f,1 They may be the same or different, and this embodiment does not limit this.

[0225] S1223: The first low-frequency energy change rate is greater than the first change rate threshold corresponding to the first reference path, the first transient characteristic is greater than the first transient characteristic threshold corresponding to the first reference path, the second low-frequency energy change rate is greater than the first change rate threshold corresponding to the second reference path, and the second transient characteristic is greater than the first transient characteristic threshold corresponding to the second reference path. The current scene is determined to be a sudden low-frequency noise scene.

[0226] For example, in a burst low-frequency noise scenario, the characteristics are described as follows:

[0227] The energy of short-term low-frequency (<150Hz) noise changes rapidly, showing transient pulse characteristics.

[0228] In the sudden low-frequency noise scenario, the low-frequency energy change rate and transient characteristics judgment criteria of the first reference path are:

[0229] a) The first low-frequency energy change rate ΔE f (t)Satisfy:

[0230] ΔE f (t)>γ f,1

[0231] Among them, γf,1 Indicates a first change rate threshold corresponding to the first reference path.

[0232] b) First transient characteristic κ f (t)Satisfy:

[0233] κ f (t)>γ f,2

[0234] Among them, γ f,2 Indicates the first transient characteristic threshold corresponding to the first reference path.

[0235] In the case of sudden low-frequency noise, the low-frequency energy change rate and transient characteristics judgment criteria of the second reference path are:

[0236] a) The second low-frequency energy change rate ΔE b (t)Satisfy:

[0237] ΔE b (t)>γ b,1

[0238] Among them, γ b,1 Represents the first change rate threshold corresponding to the second reference path. b,1 With γ f,1 They may be the same or different, and this embodiment does not limit this.

[0239] b) Second transient characteristic κ b (t)Satisfy:

[0240] κ b (t)>γ b,2

[0241] Among them, γ b,2 Represents the first transient characteristic threshold corresponding to the second reference path. b,2 With γ b,2 They may be the same or different, and this embodiment does not limit this.

[0242] S1224: The total energy of the first environmental noise acquisition signal is less than the third energy threshold corresponding to the first reference path, and the total energy of the second environmental noise acquisition signal is less than the third energy threshold corresponding to the second reference path, and the current scene is determined to be a low-noise scene.

[0243] Exemplarily, in a low noise scenario, the features are described as follows:

[0244] The overall energy level of the ambient noise is low, and the total energy is lower than the set threshold. Noise reduction may introduce obvious background noise.

[0245] In low-noise scenarios, the total energy judgment criteria for the first reference path are:

[0246] The total energy E of the first environmental noise acquisition signal total,f satisfy:

[0247] E total,f <η f,quiet

[0248] Among them, η f,quiet Indicates the third energy threshold corresponding to the first reference path.

[0249] In low-noise scenarios, the total energy judgment criteria for the second reference path are:

[0250] The total energy E of the second environmental noise acquisition signal total,b satisfy:

[0251] E total,b <η b,quiet

[0252] Among them, η b,quiet represents the third energy threshold corresponding to the second reference path. b,quiet With η f,quiet They may be the same or different, and this embodiment does not limit this.

[0253] As some optional implementations, the first filter and the second filter each include a plurality of second-order IIR (Infinite Impulse Response) filters connected in series, and each second-order IIR filter has a different frequency range.

[0254] The second-order IIR filter is a digital filter that has an infinite impulse response. Unlike FIR (Finite Impulse Response) filters, the output of the IIR filter depends not only on the current and past input signals, but also on the past output signals. This feature enables the IIR filter to achieve higher filtering performance at a lower order.

[0255] By adjusting the coefficients of the second-order IIR filter, the shape of the signal can be changed, for example, certain frequency components can be enhanced or weakened.

[0256] As some optional implementations, the active noise reduction method further includes S250: obtaining a preset adjustment strategy, where the preset adjustment strategy at least includes a filter coefficient corresponding to a filter on each first path in each noise scene.

[0257] In S230, according to the target noise scenario, the first filter on each first path is controlled to operate with a target filter coefficient corresponding to the target noise scenario to obtain a target noise signal, including S231.

[0258] S231: Using the filter coefficient corresponding to each filter in the target noise scenario in the preset adjustment strategy as the target filter coefficient to obtain the target noise signal.

[0259] As some optional implementations, taking two feedforward microphones as an example, S231 includes S232-S235.

[0260] S232: When the target noise scene is a normal noise scene, the first target filter coefficient is a first default filter coefficient, and the second target filter coefficient is a second default filter coefficient.

[0261] Specifically, according to the recognized scene, the filter coefficients of the two filters are adjusted by dynamic control of the front and rear channels respectively. Where x∈{f,b}.

[0262] In normal noise scenarios, use the default filter coefficient H default,x (f):

[0263]

[0264] S233: When the target noise scenario is an ultra-low frequency noise enhancement scenario, the first target filter coefficient is the first filter coefficient, and the second target filter coefficient is the second filter coefficient; the first filter coefficient is the filter coefficient obtained by reducing the gain of one or more second-order IIR filters in the first filter whose frequency range is lower than the first frequency; the second filter coefficient is the filter coefficient obtained by reducing the gain of one or more second-order IIR filters in the second filter whose frequency range is lower than the first frequency.

[0265] Specifically, in the ultra-low frequency noise enhancement scenario, the gain of one or more low-frequency second-order IIR filters in the two filters is dynamically reduced:

[0266]

[0267] Among them, α x,1 The first fixed coefficient determined for the experimental phase.

[0268] Specifically, it can be determined during the test phase before the headphones leave the factory which low-frequency second-order IIR filter gain is to be reduced. The gain of a certain frequency band in the second-order IIR filter can be reduced, or the gain of one or more frequency points. The amount of reduction can also be a fixed coefficient determined experimentally.

[0269] S234: In a sudden low-frequency noise scenario, the first target filter coefficient is the third filter coefficient, and the second target filter coefficient is the fourth filter coefficient; the third filter coefficient is a filter coefficient obtained by reducing the gain of one or more second-order IIR filters in the first filter whose frequency range is lower than the second frequency; the fourth filter coefficient is a filter coefficient obtained by reducing the gain of one or more second-order IIR filters in the second filter whose frequency range is lower than the second frequency; the second frequency is greater than the first frequency.

[0270] Specifically, in the case of sudden low-frequency noise, the gain of one or more low-frequency second-order IIR filters in the two filters is transiently reduced:

[0271]

[0272] Among them, α x,2 The second fixed coefficient determined for the experimental phase.

[0273] S235: In a low noise scenario, the first target filter coefficient is the fifth filter coefficient, and the second target filter coefficient is the sixth filter coefficient; the fifth filter coefficient is the filter coefficient obtained by reducing the gain of all second-order IIR filters in the first filter; the sixth filter coefficient is the filter coefficient obtained by reducing the gain of all second-order IIR filters in the second filter.

[0274] Specifically, in low-noise scenarios, the total gain of the two filters is dynamically reduced:

[0275]

[0276] Among them, α x,3 The third fixed coefficient determined for the experimental phase.

[0277] This embodiment can adjust the filter coefficients of the filter according to multiple scenes respectively, so as to achieve a good noise reduction effect and greatly reduce the phenomenon of buzzing or rustling sounds emitted by the speaker.

[0278] In some other implementations, a feedback microphone is further installed in the earphone of this embodiment, and the feedback microphone is used for active noise reduction and detecting the noise inside the earphone, and feeding it back to the control circuit to further optimize the noise reduction effect.

[0279] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0280] Figure 7 A schematic diagram of the principle of an active noise reduction system disclosed in an embodiment of the present application, including headphones and testing equipment.

[0281] The testing device is used to perform system identification on a first system in the headset through a frequency sweeping signal to determine a first default filter coefficient of a first filter in the headset; the first system includes a first feedforward microphone and a speaker for the first filter in the headset; the second system in the headset is used to perform system identification on a second system in the headset through a frequency sweeping signal to determine a second default filter coefficient of a second filter in the headset; the second system includes a second feedforward microphone and a speaker; and the first default filter coefficient and the second default filter coefficient are written into a processor of the headset.

[0282] The earphones are used to turn on active noise reduction and execute the active noise reduction method of any of the above embodiments.

[0283] A swept frequency signal is a test signal used to evaluate and test the noise reduction performance of headphones. A swept frequency signal is a signal whose frequency changes over time, and its frequency range covers the entire frequency range audible to the human ear (usually 20Hz to 20kHz). This signal can help testers understand the noise reduction effect of headphones at different frequencies. In addition, the frequency, amplitude, and phase of the swept frequency signal are all known.

[0284] Specifically, the first system consisting of the first feedforward microphone and the speaker is first identified by a frequency sweep signal, and then the first default filter coefficient (including the first weight) of the first filter is designed by the feedforward noise reduction principle and written into the processor. Similarly, the second system consisting of the second feedforward microphone and the speaker is identified by a frequency sweep signal, and then the second default filter coefficient (including the second weight) of the second filter is designed by the feedforward noise reduction principle and written into the processor. Finally, the headset turns on active noise reduction to achieve a noise reduction effect. Among them, the headset performs scene recognition in real time and adjusts the filter coefficients of the first filter and the second filter respectively to achieve accurate and efficient noise reduction effects.

[0285] System identification refers to the testing of some transfer functions of the entire headphone system, such as the transfer function from the feedforward microphone signal to the artificial ear signal, and the transfer function from the headphone speaker signal to the artificial ear signal. These transfer functions mainly characterize some path information of the headphone structure and are used to calculate the filter coefficients of the filter. The artificial ear signal refers to the process of simulating the human ear's reception and processing of sound, which is used to test and evaluate the performance of noise reduction headphones.

[0286] In some other optional implementations, the test device further performs system identification on the first system and the second system through a plurality of known noise scenarios, obtains the second filter coefficient, the third filter coefficient, the fourth filter coefficient, the fifth filter coefficient, and the sixth filter coefficient of the first filter and the second filter, respectively, and writes the second filter coefficient, the third filter coefficient, the fourth filter coefficient, the fifth filter coefficient, and the sixth filter coefficient of the first filter and the second filter into the processor of the headset. When the headset recognizes the target noise scenario, the corresponding filter coefficient is called for filtering.

[0287] Corresponding to the active noise reduction method described in the above embodiment, Figure 8 A structural block diagram of an active noise reduction device provided in an embodiment of the present application is shown. For ease of explanation, only the parts related to the embodiment of the present application are shown.

[0288] Reference Figure 8 , the device comprises:

[0289] An acquisition module 310 is used to acquire multiple environmental noise acquisition signals through multiple feedforward microphones of the headset; each feedforward microphone corresponds to a first path, and each environmental noise acquisition signal is transmitted via a first path;

[0290] The identification module 320 is used to identify the target noise scene where the earphone is located according to the multiple environmental noise collection signals; the target noise scene is one of the one or more noise scenes;

[0291] The control module 330 is used to control the filter on each first path to operate with a target filter coefficient corresponding to the target noise scene according to the target noise scene, so as to obtain a target noise signal; the target filter coefficients corresponding to each filter in different target noise scenes are different;

[0292] The playing module 340 is used to control the loudspeaker to output the target noise signal to form a secondary sound source; the secondary sound source is used to offset the ambient noise ear signal reaching the human ear through the second path.

[0293] It should be noted that the information interaction, execution process, etc. between the above-mentioned devices / units are based on the same concept as the method embodiment of the present application. Their specific functions and technical effects can be found in the method embodiment part and will not be repeated here.

[0294] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0295] An embodiment of the present application also provides an earphone, which includes: at least one processor, a memory, and a computer program stored in the memory and executable on the at least one processor, wherein the processor implements the steps in any of the above-mentioned method embodiments when executing the computer program.

[0296] An embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps in the above-mentioned method embodiments can be implemented.

[0297] An embodiment of the present application provides a computer program product. When the computer program product is run on an earphone, the earphone can implement the steps in the above-mentioned method embodiments when executing the computer program product.

[0298] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, which can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may at least include: any entity or device that can carry the computer program code to the headset, a recording medium, a computer memory, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), an electric carrier signal, a telecommunication signal, and a software distribution medium. For example, a USB flash drive, a mobile hard disk, a magnetic disk or an optical disk. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electric carrier signals and telecommunication signals.

[0299] The program code embodied on the computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0300] The computer program code for performing the operation of the embodiment of the application can be written with one or more programming languages ​​or their combination, and the programming language includes object-oriented programming languages, such as python, Java, Smalltalk, C++, and also includes conventional procedural programming languages, such as "C" language or similar programming languages. The program code can be executed completely on the user's computer, partially on the user's computer, executed as an independent software package, partially on the user's computer and partially on the remote computer, or executed completely on the remote computer or server. In the case of a remote computer, the remote computer can include a local area network (LAN) or a wide area network (WAN)--connected to the user's computer through any type of network, or, can be connected to an external computer (for example, utilizing an Internet service provider to connect through the Internet).

[0301] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0302] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0303] In the embodiments provided in the present application, it should be understood that the disclosed devices / earphones and methods can be implemented in other ways. For example, the device / earphone embodiments described above are merely schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0304] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0305] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. An active noise reduction method, characterized in that: Applied to headphones, the method comprises: Acquire multiple environmental noise collection signals through multiple feedforward microphones of the headset; each of the feedforward microphones corresponds to a first path, and each of the environmental noise collection signals is transmitted via one of the first paths; According to the multiple environmental noise collection signals, identifying the target noise scene in which the headset is located; the target noise scene is one of the one or more noise scenes; According to the target noise scene, controlling each filter on the first path to operate with a target filter coefficient corresponding to the target noise scene to obtain a target noise signal; the target filter coefficients corresponding to each filter in different target noise scenes are different; The loudspeaker is controlled to output the target noise signal to form a secondary sound source; the secondary sound source is used to cancel the ambient noise ear signal reaching the human ear through the second path.

2. The method according to claim 1, characterized in that The method further comprises: Acquire a preset adjustment strategy, wherein the preset adjustment strategy includes a filter coefficient corresponding to each filter on the first path in each noise scene; According to the target noise scenario, controlling the filter on each of the first paths to operate with a target filter coefficient corresponding to the target noise scenario to obtain a target noise signal includes: The filter coefficient corresponding to each of the filters in the target noise scenario in the preset adjustment strategy is used as a target filter coefficient to obtain a target noise signal.

3. The active noise reduction method according to claim 2, characterized in that: The noise scene includes a normal noise scene; The filter coefficient corresponding to each filter in the target noise scenario in the preset adjustment strategy is used as the target filter coefficient, including: When the target noise scene is a normal noise scene, the target filter coefficient of each filter is a default filter coefficient.

4. The active noise reduction method according to claim 2, characterized in that: The noise scene includes an ultra-low frequency noise enhancement scene; The filter coefficient corresponding to each filter in the target noise scenario in the preset adjustment strategy is used as the target filter coefficient, including: When the target noise scenario is an ultra-low frequency noise enhancement scenario, the target filter coefficient of each filter is a first filter coefficient, and the first filter coefficient of each filter is the same or different; the first filter coefficient is a filter coefficient obtained by reducing the gain of one or more second-order IIR filters in the filter whose frequency range is lower than the first frequency.

5. The active noise reduction method according to claim 2, characterized in that: The noise scene includes a sudden low-frequency noise scene; The filter coefficient corresponding to each filter in the target noise scenario in the preset adjustment strategy is used as the target filter coefficient, including: When the target noise scenario is the burst low-frequency noise scenario, the target filter coefficient of each of the filters is a second filter coefficient, and the second filter coefficient of each of the filters is the same or different; the second filter coefficient is a filter coefficient obtained by reducing the gain of one or more second-order IIR filters in the filter whose frequency range is lower than the second frequency.

6. The active noise reduction method according to claim 2, characterized in that: The noise scene includes a low noise scene; The filter coefficient corresponding to each filter in the target noise scenario in the preset adjustment strategy is used as the target filter coefficient, including: When the target noise scene is the low noise scene, the target filter coefficient of each of the filters is a third filter coefficient, and the third filter coefficient of each of the filters is the same or different; the third filter coefficient is a filter coefficient obtained by reducing the gain of all second-order IIR filters in the filter.

7. The active noise reduction method according to any one of claims 1 to 6, characterized in that: The step of identifying the target noise scene in which the headset is located according to the multiple environmental noise collection signals includes: Performing spectrum analysis, energy analysis and characteristic analysis on the multiple environmental noise collection signals; The target noise scene in which the earphone is located is identified according to the frequency spectrum distribution, energy level and time variation characteristics of the multiple environmental noise acquisition signals.

8. The active noise reduction method according to claim 7, characterized in that: The performing spectrum analysis, energy analysis and characteristic analysis on the multiple environmental noise acquisition signals includes: The multiple environmental noise signals are subjected to discrete Fourier transform to obtain multiple frequency domain signals; Determining a plurality of spectral energy densities according to the plurality of frequency domain signals; Determining the total energy of the multiple environmental noise collection signals according to the multiple spectrum energy densities; Determine, according to the plurality of spectrum energy densities, a plurality of ultra-low frequency band energies less than a first frequency and a plurality of low frequency band energies less than a second frequency; the first frequency is less than the second frequency; According to the ratio of each ultra-low frequency band energy to the total energy of the environmental noise collection signal corresponding to each ultra-low frequency band energy, a plurality of ultra-low frequency energy proportions are obtained; Determining a plurality of low-frequency energy change rates according to the plurality of low-frequency band energies; Determining a plurality of transient characteristics according to peak values ​​and average values ​​of the plurality of environmental noise acquisition signals; A plurality of spectrum smoothnesses are determined according to the distribution uniformity of the plurality of spectrum energy densities of the frequency components in the entire frequency range.

9. The active noise reduction method according to claim 8, characterized in that: The step of determining a target noise scene according to the spectrum distribution, energy level and time variation characteristics of the plurality of environmental noise acquisition signals comprises: The smoothness of the multiple spectra is less than the first smoothness threshold corresponding to each of the first paths, and the total energy of the multiple environmental noise collection signals is within the first energy range corresponding to each of the first paths, and the current scene is determined to be a normal noise scene.

10. The active noise reduction method according to claim 8, characterized in that: The step of determining a target noise scene according to the spectrum distribution, energy level and time variation characteristics of the plurality of environmental noise acquisition signals comprises: The energies of the multiple ultra-low frequency bands are greater than the second energy threshold corresponding to each of the first paths, and the proportions of the multiple ultra-low frequency energies are greater than the first proportion threshold corresponding to each of the first paths, and the current scene is determined to be an ultra-low frequency noise enhanced scene.

11. The active noise reduction method according to claim 8, characterized in that: The step of determining a target noise scene according to the spectrum distribution, energy level and time variation characteristics of the plurality of environmental noise acquisition signals comprises: The multiple low-frequency energy change rates are greater than the first change rate thresholds corresponding to the respective first paths, and the multiple transient characteristics are greater than the first transient characteristic thresholds corresponding to the respective first paths, and the current scene is determined to be a sudden low-frequency noise scene.

12. The active noise reduction method according to claim 8, characterized in that: The step of determining a target noise scene according to the spectrum distribution, energy level and time variation characteristics of the plurality of environmental noise acquisition signals comprises: The total energy of the multiple environmental noise collection signals is less than the third energy threshold corresponding to each of the first paths, and the current scene is determined to be a low-noise scene.

13. An active noise reduction system, characterized in that: Includes headphones and test equipment; The test equipment is used to: Performing system identification on multiple adjustment systems in the earphones through frequency sweep signals to determine the filter coefficient of each filter in the earphones; any of the adjustment systems includes any feedforward microphone and a speaker; The earphone is used to execute the method according to any one of claims 1-12.

14. An active noise reduction device, characterized in that: include: An acquisition module, used for acquiring multiple environmental noise collection signals through multiple feedforward microphones of the headset; Each of the feedforward microphones corresponds to a first path, and each of the environmental noise collection signals is transmitted via a first path; An identification module, configured to identify a target noise scene in which the headset is located according to the plurality of environmental noise collection signals; The target noise scene is one of one or more noise scenes; A control module, configured to control the filter on each of the first paths to operate with a target filter coefficient corresponding to the target noise scene according to the target noise scene, so as to obtain a target noise signal; The target filter coefficients corresponding to each filter in different target noise scenes are different; A playing module controls the loudspeaker to output the target noise signal to form a secondary sound source; The secondary sound source is used to cancel the ambient noise in-ear signal reaching the human ear through the second path.

15. A headset comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 12 is implemented.

16. The headset according to claim 15, characterized in that The earphone is an open-type earphone, comprising a body, an ear hook and a rotating shaft connecting part; the multiple feedforward microphones are located on one or more of the body, the ear hook and the rotating shaft connecting part.

17. A computer program product, characterized in that When the computer program product runs on the headset, the headset is caused to execute the method according to any one of claims 1 to 12.

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