Active noise reduction circuit, method, device and storage medium with NICam transparency

Abstract

The present invention discloses an active noise reduction circuit, method, device and storage medium with clear sound, which are used to solve the technical problem in the prior art that it is impossible to allow a user to clearly hear specific sounds in the environment while actively reducing ambient noise. The active noise reduction circuit includes: an active noise reduction unit, which is used to actively reduce the noise of a first audio signal picked up, and obtain an inverted audio signal with a phase opposite to the ambient noise; a sub-band noise reduction unit, which is used to perform sub-band noise reduction on a second audio signal picked up from the external environment, and obtain a third audio signal after the steady-state noise of the external environment is reduced; wherein the first audio signal and the second audio signal are picked up simultaneously; and a signal output unit, which is used to modulate the inverted audio signal with the third audio signal, and obtain a fourth audio signal after noise reduction.

Description

Technical Field

[0001] The present invention relates to the field of electronic technology, and in particular to an active noise reduction circuit, method, device and storage medium with NICam transparency. Background Art

[0002] At present, active noise reduction headphones generally include deep noise reduction mode, transparency mode, and noise reduction off mode.

[0003] In the field of consumer electronics headphones, the goal of transparency mode is mainly to allow the wearer to hear the sounds of the external environment even without taking off the headphones, such as being able to smoothly listen to the voice of the conversation partner and some important prompt sounds.

[0004] In existing technology, the transparency mode of active noise-cancelling headphones uses the feedforward path of the active noise cancellation (ANC) to monitor ambient sound by measuring the sound transfer function from the feedforward microphone to the eardrum when the headphones are worn and when they are not. While this method allows the wearer to hear desired speech and notification sounds, it also allows the wearer to hear unwanted ambient noise. Especially in environments with high steady-state noise levels, using this transparency mode can affect the wearer's comfort and intelligibility during conversations.

[0005] In view of this, how to allow users to clearly hear specific sounds in the environment while actively reducing ambient noise has become a technical problem that needs to be solved urgently. Summary of the Invention

[0006] The present invention provides an active noise reduction circuit, method, device and storage medium with clear sound, which are used to solve the technical problem in the prior art that it is impossible to allow users to clearly hear specific sounds in the environment while actively reducing ambient noise.

[0007] In the first aspect, to solve the above technical problems, the embodiments of the present invention provide a technical solution for an active noise reduction circuit with NICam transparency as follows:

[0008] an active noise reduction unit, configured to perform active noise reduction on the picked-up first audio signal to obtain an anti-phase audio signal having a phase opposite to that of the ambient noise;

[0009] a sub-band noise reduction unit, configured to perform sub-band noise reduction on a second audio signal picked up from an external environment to obtain a third audio signal after the steady-state noise of the external environment is reduced; wherein the first audio signal and the second audio signal are picked up simultaneously;

[0010] The signal output unit is configured to modulate the inverted audio signal and the third audio signal to obtain a fourth audio signal after noise reduction.

[0011] In one possible implementation, the active noise reduction unit includes:

[0012] a fixed active noise reduction circuit or an adaptive active noise reduction circuit, and a compensation filter connected between the sub-band noise reduction unit and the fixed active noise reduction circuit or the adaptive active noise reduction circuit;

[0013] The fixed active noise reduction circuit uses fixed noise reduction parameters to perform active noise reduction on the first audio signal, thereby obtaining the inverted audio signal; the adaptive active noise reduction circuit uses adaptive coefficients to perform active noise reduction on the first audio signal, thereby obtaining the inverted audio signal; the compensation filter is used to process the third audio signal and then input it into the fixed active noise reduction circuit or the adaptive active noise reduction circuit to eliminate the third audio signal from the first audio signal.

[0014] In one possible implementation, the fixed active noise reduction circuit includes:

[0015] A feedforward filter circuit, or any one or all of the feedforward filter circuit and the feedback filter circuit; wherein the feedforward filter circuit is used to generate an inverted audio signal with a phase opposite to that of noise in the external environment, and the feedback filter circuit is used to generate an inverted audio signal with a phase opposite to that of noise in the ear canal environment.

[0016] In a possible implementation manner, when the first audio signal includes a sub-audio signal picked up from the external environment, the second audio signal is obtained by downsampling the sub-audio signal.

[0017] In a possible implementation manner, the sub-band noise reduction unit is further configured to superimpose the received playback audio onto the audio signal after sub-band noise reduction to obtain the third audio signal.

[0018] In a second aspect, an embodiment of the present invention provides an active noise reduction method with NICam transparency, comprising:

[0019] Active noise reduction is performed on the picked-up first audio signal to obtain an anti-phase audio signal having a phase opposite to that of the ambient noise;

[0020] performing sub-band noise reduction on a second audio signal picked up from an external environment to obtain a third audio signal after steady-state noise of the external environment is reduced; wherein the first audio signal and the second audio signal are picked up simultaneously;

[0021] The inverted audio signal is modulated with the third audio signal to obtain a fourth audio signal after noise reduction.

[0022] In one possible implementation, active noise reduction is performed on the picked-up first audio signal to obtain an anti-phase audio signal having a phase opposite to that of the ambient noise, including:

[0023] performing signal compensation on the first audio signal using the third audio signal to eliminate the third audio signal contained in the first audio signal, thereby obtaining a compensated audio signal;

[0024] Performing fixed active noise reduction or adaptive active noise reduction on the compensated audio signal to obtain the inverted audio signal; wherein the fixed active noise reduction includes one or both of feedforward filtering and feedback filtering.

[0025] A possible implementation method of performing sub-band noise reduction on a second audio signal picked up from an external environment to obtain a third audio signal after the steady-state noise of the external environment is reduced includes:

[0026] When the first audio signal includes a sub-audio signal picked up from the external environment, downsampling the sub-audio signal to obtain the second audio signal;

[0027] Perform sub-band noise reduction on the second audio signal to obtain the third audio signal.

[0028] In a third aspect, an embodiment of the present invention provides an electronic device, comprising the active noise reduction circuit with NICam transparency as described in the first aspect.

[0029] In a fourth aspect, an embodiment of the present invention provides a readable storage medium, including:

[0030] Memory,

[0031] The memory is used to store instructions, and when the instructions are executed by the processor, the device including the readable storage medium performs the method as described in the second aspect.

[0032] Through the technical solutions in one or more of the above embodiments of the present invention, the embodiments of the present invention have at least the following technical effects:

[0033] In the embodiment provided by the present invention, an active noise reduction unit is used to perform active noise reduction on a picked-up first audio signal to obtain an inverted audio signal having a phase opposite to that of the ambient noise; a sub-band noise reduction unit is used to perform sub-band noise reduction on a second audio signal picked up from the external environment to obtain a third audio signal after steady-state noise of the external environment is reduced; wherein the first audio signal and the second audio signal are picked up simultaneously; a signal output unit is used to modulate the inverted audio signal with the third audio signal to obtain a fourth audio signal after noise reduction; thereby, the active noise reduction circuit can achieve the goal of reducing ambient noise while hearing the sound of the external environment after steady-state noise is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of signal processing for the sub-band noise reduction unit;

[0035] Figure 2 A schematic structural diagram of an active noise reduction circuit with NICam transparency provided by an embodiment of the present invention;

[0036] Figure 3 Schematic diagram of the structure of the active noise reduction unit provided in an embodiment of the present invention Figure 1 ;

[0037] Figure 4 Schematic diagram of the structure of the active noise reduction unit provided in an embodiment of the present invention Figure 2 ;

[0038] Figure 5 A schematic diagram of an achievable circuit structure of a feedforward filter circuit provided in an embodiment of the present invention Figure 1 ;

[0039] Figure 6 A schematic diagram of an achievable circuit structure of a feedforward filter circuit provided in an embodiment of the present invention Figure 2 ;

[0040] Figure 7 A schematic diagram of an achievable circuit structure of a feedback filter circuit provided in an embodiment of the present invention Figure 1 ;

[0041] Figure 8 A schematic diagram of an achievable circuit structure of a feedback filter circuit provided in an embodiment of the present invention Figure 2 ;

[0042] Figure 9 A schematic diagram of an achievable circuit structure of an adaptive active noise reduction circuit provided by an embodiment of the present invention Figure 1 ;

[0043] Figure 10 A schematic diagram of an achievable circuit structure of an adaptive active noise reduction circuit provided by an embodiment of the present invention Figure 2 ;

[0044] Figure 11 A schematic diagram of an achievable circuit structure of a sub-band noise reduction unit provided in an embodiment of the present invention Figure 1 ;

[0045] Figure 12 A schematic diagram of an achievable circuit structure of a sub-band noise reduction unit provided in an embodiment of the present invention Figure 2 ;

[0046] Figure 13 A schematic diagram of an achievable circuit structure of a sub-band noise reduction circuit provided in an embodiment of the present invention Figure 3 ;

[0047] Figure 14 A schematic diagram of an achievable circuit structure of a sub-band noise reduction circuit provided in an embodiment of the present invention Figure 4 ;

[0048] Figure 15 A schematic diagram of an achievable circuit structure of a signal output unit provided in an embodiment of the present invention;

[0049] Figure 16 A schematic diagram of an achievable circuit structure of an active noise reduction circuit with NICam transparency provided by an embodiment of the present invention Figure 1 ;

[0050] Figure 17 A schematic diagram of an achievable circuit structure of an active noise reduction circuit with NICam transparency provided by an embodiment of the present invention Figure 2 ;

[0051] Figure 18 This is a flow chart of an active noise reduction method with NICam transparency provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The embodiments of the present invention provide an active noise reduction circuit, method, device and storage medium with NICam transparency to solve the technical problem in the prior art that active noise reduction headphones can only reduce ambient noise.

[0053] Before introducing the solution of the present invention, the basic principle of the sub-band noise reduction unit used in the present invention is first introduced:

[0054] See Figure 1 Schematic diagram of signal processing for the sub-band noise reduction unit.

[0055] The sub-band denoising unit adopts a sub-band denoising algorithm based on the weighted overlap-add (WOLA) filter bank framework, including: m The WOLA analysis module consists of a WOLA (z)) and a decimator (L), a sub-band signal processing module, and a WOLA synthesis module consisting of an interpolator and a synthesis filter. The WOLA analysis module decomposes the time domain input signal (xn) into a set of complex sub-band time-frequency signals (x1(Ln)~xn) with equal bandwidth. m (Ln)), and the WOLA synthesis module combines multiple sub-band signals (v1(n)~v m (n)) is restored to a time domain signal (y(n)).

[0056] WOLA is a flexible sub-band processing method that can flexibly adjust the balance between delay, distortion, and computational complexity. For applications with low delay requirements, WOLA can reduce delay by reducing the number of sub-bands and the length of the analysis and synthesis filters, easily reducing delay to less than 1ms, meeting the ultra-low delay requirement for a transparent effect. The sub-band signal processing module mainly calculates the noise reduction filter weights and controls the dynamic range. The calculation of the noise reduction filter weights can be performed using well-known noise estimation algorithms (such as minimum tracking and recursive averaging) and speech denoising algorithms (such as spectral subtraction, Wiener filtering, statistical weighting, etc.). Dynamic range control is mainly used to prevent audio distortion and excessive volume from damaging the human ear.

[0057] The technical solution in the embodiments of the present application is to solve the above technical problems, and the overall idea is as follows:

[0058] Provided are active noise-cancelling headphones with clear and transparent sound, comprising: an active noise-cancelling unit for performing active noise reduction on a first audio signal picked up, thereby obtaining an inverted audio signal having a phase opposite to that of ambient noise; a sub-band noise-cancelling unit for performing sub-band noise reduction on a second audio signal picked up from an external environment, thereby obtaining a third audio signal after steady-state noise in the external environment has been reduced; wherein the first audio signal and the second audio signal are picked up simultaneously; and a signal output unit for modulating the inverted audio signal with the third audio signal, thereby obtaining a fourth audio signal after noise reduction.

[0059] In the above scheme, an active noise reduction unit is used to perform active noise reduction on the picked-up first audio signal to obtain an inverted audio signal with a phase opposite to that of the ambient noise; a sub-band noise reduction unit is used to perform sub-band noise reduction on the second audio signal picked up from the external environment to obtain a third audio signal after steady-state noise of the external environment is reduced; wherein the first audio signal and the second audio signal are picked up at the same time; and a signal output unit is used to modulate the inverted audio signal with the third audio signal to obtain a fourth audio signal after noise reduction; thereby, the active noise reduction circuit can hear the sound of the external environment after steady-state noise is reduced while reducing the ambient noise.

[0060] In order to better understand the above technical solution, the technical solution of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations on the technical solution of the present invention. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0061] Please refer to Figure 2 , is a schematic structural diagram of an active noise reduction circuit with NICam transparency provided by an embodiment of the present invention, the active noise reduction circuit comprising:

[0062] The active noise reduction unit 10 is configured to perform active noise reduction on the picked-up first audio signal to obtain an anti-phase audio signal having a phase opposite to that of the ambient noise.

[0063] The sub-band noise reduction unit 20 is configured to perform sub-band noise reduction on the second audio signal picked up from the external environment to obtain a third audio signal after the steady-state noise of the external environment is reduced; wherein the first audio signal and the second audio signal are picked up simultaneously.

[0064] It should be understood that the first audio signal is picked up from an environment, and the environment corresponding to the first audio signal can be one of the external environment and the ear canal environment, or both, without limitation. The second audio signal is picked up from the external environment, and sub-band noise reduction is performed on the second audio signal to obtain a third audio signal after the steady-state noise in the external environment is reduced. By reducing the steady-state sound sources in the external environment, a third audio signal including all non-steady-state sound sources, such as speech, prompt sounds, and whistles, can be obtained. Reducing steady-state sound sources can be achieved by adjusting the parameters of the sub-band noise reduction.

[0065] By performing sub-band noise reduction on the second audio signal, the collected second audio signal can be divided into multiple sub-bands for noise reduction, which can achieve a better noise reduction effect while reducing latency and avoid echoes when the sound is played back.

[0066] The signal output unit 30 is configured to modulate the inverted audio signal and the third audio signal to obtain a fourth audio signal after noise reduction.

[0067] The active noise reduction circuit in the embodiment of the present invention can be used in headphone products, communication equipment, wearable devices, etc.

[0068] By using the active noise reduction unit 10 to actively reduce the noise of the picked up first audio signal, an inverted audio signal with a phase opposite to the ambient noise is obtained; at the same time, the sub-band noise reduction unit 20 is used to perform sub-band noise reduction on the second audio signal picked up from the external environment, and a third audio signal is obtained after the steady-state noise of the external environment is reduced; finally, the signal output unit 30 is used to modulate the inverted audio signal with the third audio signal to obtain a fourth audio signal after noise reduction; thereby, the active noise reduction circuit can reduce the ambient noise while also clearly hearing the sound of the environment after the steady-state noise is reduced, achieving the technical effect of clear and transparent sound.

[0069] See Figure 3 and Figure 4 , Figure 3 Schematic diagram of the structure of the active noise reduction unit provided in an embodiment of the present invention Figure 1 , Figure 4 Schematic diagram of the structure of the active noise reduction unit provided in an embodiment of the present invention Figure 2 .

[0070] The active noise reduction unit 10 includes a fixed active noise reduction circuit 101 or an adaptive active noise reduction circuit 102 , and a compensation filter 103 connected between the sub-band noise reduction unit 20 and the fixed active noise reduction circuit 101 or the adaptive active noise reduction circuit 102 .

[0071] The fixed active noise reduction circuit 101 is an inverted audio signal obtained by actively reducing the noise of the first audio signal using fixed noise reduction parameters, and the adaptive active noise reduction circuit 102 is an inverted audio signal obtained by actively reducing the noise of the first audio signal using adaptive coefficients. The compensation filter 103 is used to process the third audio signal and input it into the fixed active noise reduction circuit 101 or the adaptive active noise reduction circuit 102 to eliminate the third audio signal in the first audio signal.

[0072] exist Figure 3 In the embodiment, the active noise reduction unit 10 composed of the fixed active noise reduction circuit 101 and the compensation filter 103 can quickly perform active noise reduction on the first audio signal and the third audio signal processed by the compensation filter 103 to obtain an inverted audio signal.

[0073] exist Figure 4 In the figure, the active noise reduction unit 10, which is composed of an adaptive active noise reduction circuit 102 and a compensation filter 103, can automatically adjust the adaptive parameters according to the characteristics of the ambient noise, and perform active noise reduction on the first audio signal and the third audio signal processed by the compensation filter 103 to obtain an inverted audio signal.

[0074] It should be noted that since the first audio signal includes signals corresponding to ambient sound and / or audio playback sound, these signals will be significantly attenuated by active noise reduction if not processed. Therefore, a compensation filter 103 is required in the active noise reduction unit 10. The signal output by the sub-band noise reduction unit 20 is sent to the compensation filter 103 for processing and then superimposed with the third audio signal for noise reduction.

[0075] The fixed active noise reduction circuit 101 comprises:

[0076] Any one or all of the feedforward filter circuit and the feedback filter circuit; wherein the feedforward filter is used to generate an inverted audio signal with a phase opposite to that of the noise in the external environment, and the feedback filter is used to generate an inverted audio signal with a phase opposite to that of the noise in the ear canal environment.

[0077] See Figure 5 and Figure 6 , Figure 5 A schematic diagram of an achievable circuit structure of a feedforward filter circuit provided in an embodiment of the present invention Figure 1 , Figure 6 A schematic diagram of an achievable circuit structure of a feedforward filter circuit provided in an embodiment of the present invention Figure 2 .

[0078] exist Figure 5 The active noise reduction circuit 101 is composed of a feedforward filter circuit 101a. The feedforward filter circuit 101a may include a first adder (S1) and a feedforward filter connected in sequence. One input end of the first adder (S1) is used to receive the first audio signal, and the other input end is used to receive the third audio signal processed by the compensation filter 103. The output end of the first adder (S1) is connected to the input end of the feedforward filter. The feedforward filter is used to process the received signal to obtain an inverted audio signal.

[0079] See Figure 6 The feedforward filtering circuit 101a may further include a first sampling circuit for sampling the sound in the external environment to obtain a first audio signal.

[0080] It should be noted that, when the fixed active noise reduction circuit 101 is composed of the feedforward filter circuit 101 a , the first audio signal is an audio signal corresponding to the sound in the external environment.

[0081] See Figure 7 and Figure 8 , Figure 7 A schematic diagram of an achievable circuit structure of a feedback filter circuit provided in an embodiment of the present invention Figure 1 , Figure 8 A schematic diagram of an achievable circuit structure of a feedback filter circuit provided in an embodiment of the present invention Figure 2 .

[0082] exist Figure 7 The active noise reduction circuit 101 is composed of a feedback filter circuit 101b. The feedback filter circuit 101b may include a second adder (S2) and a feedback filter connected in sequence. One input end of the second adder (S2) is used to receive the first audio signal, and the other input end is used to receive the third audio signal processed by the compensation filter 103. The output end of the second adder (S2) is connected to the input end of the feedback filter. The feedback filter is used to process the received signal to obtain an inverted audio signal.

[0083] See Figure 8 The feedback filter circuit 101b may further include a second sampling circuit for sampling the sound in the ear canal environment to obtain the first audio signal.

[0084] It should be noted that, when the fixed active noise reduction circuit 101 is composed of the feedback filter circuit 101 b , the first audio signal is an audio signal corresponding to the sound in the ear canal environment.

[0085] When the active noise reduction circuit 101 is composed of a feedforward filter circuit 101a and a feedback filter circuit 101b, the structures of the feedforward filter circuit 101a and the feedback filter circuit 101b can be respectively referred to. Figure 5 and Figure 6 、 Figure 7 and Figure 8 .

[0086] It should be noted that when the fixed active noise reduction circuit 101 is composed of a feedforward filter circuit 101a and a feedback filter circuit 101b, the first audio signal includes an audio signal corresponding to the sound in the external environment and an audio signal corresponding to the sound in the ear canal environment. The audio signal corresponding to the sound in the external environment is input into the feedforward filter circuit 101a, and the audio signal corresponding to the sound in the ear canal environment is input into the feedback filter circuit 101b. The inverted audio signal includes the signals output by the feedforward filter 101a and the feedback filter 101b.

[0087] See Figure 9 A schematic diagram of an achievable circuit structure of an adaptive active noise reduction circuit provided by an embodiment of the present invention Figure 1 The adaptive active noise reduction circuit 102 includes two adders (S3, S4) and adaptive filters respectively connected to the two adders. One input end of the third adder (S3) is used to receive an audio signal corresponding to the sound in the external environment in the first audio signal, and the other end receives an audio signal obtained by the compensation filter 103a after processing the third audio signal. One input end of the fourth adder (S4) is used to receive an audio signal corresponding to the sound in the ear canal environment in the first audio signal, and the other end receives an audio signal obtained by the compensation filter 103b after processing the third audio signal. The compensation filters 103a and 103b constitute the compensation filter 103.

[0088] See Figure 10 A schematic diagram of an achievable circuit structure of an adaptive active noise reduction circuit provided by an embodiment of the present invention Figure 2 The adaptive active noise reduction circuit 102 may further include a first sampling circuit and a second sampling circuit. The output end of the first sampling circuit is connected to the third adder (S3), and the output end of the first sampling circuit is connected to the fourth adder (S4). In this way, the adaptive active noise reduction circuit 102 can directly collect the first audio signal from the environment and perform adaptive active filtering to achieve the purpose of adaptive active noise reduction.

[0089] See Figure 11 , which is a schematic diagram of an achievable circuit structure of a sub-band noise reduction unit provided in an embodiment of the present invention. Figure 1 .

[0090] The sub-band noise reduction unit 20 includes a first downsampling circuit (downsampling 1), a sub-band noise reducer, and a first upsampling circuit (upsampling 1) connected in sequence. The sub-band noise reducer is used to perform sub-band noise reduction processing on the audio signal downsampled by the first downsampling circuit to obtain an audio signal after the environment steady-state noise is reduced. The audio signal is upsampled by the first upsampling circuit to obtain a third audio signal.

[0091] See Figure 12 , which is a schematic diagram of an achievable circuit structure of a sub-band noise reduction unit provided in an embodiment of the present invention. Figure 2 .

[0092] The sub-band noise reduction unit 20 may further include a fifth adder (S5), which is connected between the sub-band noise reducer and the upsampling unit 1 and is configured to superimpose the sub-band noise-reduced audio signal and the playback audio, and send the superimposed audio signal to the upsampling unit 1 for upsampling processing to obtain a third audio signal. In this case, the third audio signal includes both the audio signal after the steady-state noise of the environment is reduced and the playback audio.

[0093] When the first audio signal includes a sub-audio signal picked up from the external environment, the second audio signal is obtained by downsampling the sub-audio signal, that is, the sampling circuit of the sub-band noise reduction circuit can reuse the first sampling circuit in the active noise reduction unit 10.

[0094] See Figure 13 and Figure 14 , Figure 13 A schematic diagram of an achievable circuit structure of a sub-band noise reduction unit provided in an embodiment of the present invention Figure 3 , Figure 14 A schematic diagram of an achievable circuit structure of a sub-band noise reduction unit provided in an embodiment of the present invention Figure 4 .

[0095] like Figure 13 As shown, assuming that the active noise reduction unit 10 includes a fixed active noise reduction circuit 101 composed of a feedforward filtering circuit 101a and a feedback filtering circuit 101b, when the sub-band noise reduction unit includes downsampling 1, the sampling circuit corresponding to downsampling 1 reuses the first sampling circuit of the feedforward filtering circuit 101a.

[0096] It should be noted that if the active noise reduction unit 10 includes the feedforward filter circuit 101 a , the first audio signal can be downsampled to obtain the second audio signal.

[0097] like Figure 14 As shown, assuming that the active noise reduction unit 10 includes an adaptive active noise reduction circuit 102 and the sub-band noise reduction circuit includes downsampling 1, the sampling circuit corresponding to downsampling 1 reuses the first sampling circuit of the adaptive active noise reduction circuit 102.

[0098] It should be noted that since the active noise reduction unit 10 and the sub-band noise reduction unit 20 each have multiple structural forms, their connection methods are also multiple under different structural forms. Accordingly, there are also multiple forms in which the sub-band noise reduction unit 20 reuses the sampling circuit in the active noise reduction unit 10, and it should not be understood that it is limited to Figure 14 and Figure 15 The situation shown.

[0099] See Figure 15 This is a schematic diagram of a possible circuit structure of a signal output unit provided in an embodiment of the present invention. The signal output unit 30 includes a sixth adder (S6), a second upsampling circuit (upsampling 2), a digital-to-analog conversion circuit (D / A), and a speaker (S7), which are connected in sequence. The sixth adder (S6) is used to superimpose the inverted audio signal output by the active noise reduction unit 10 and the third audio signal output by the sub-band noise reduction unit 20, and send the result to the upsampling 2 to obtain a signal suitable for the sampling rate required by the digital-to-analog conversion circuit. The digital-to-analog conversion circuit then converts the third audio signal into an analog signal, which is then played by the speaker, allowing the user to hear the sound of the external environment after steady-state noise is reduced.

[0100] If the third audio signal only includes the audio signal of the external environment after steady-state noise is reduced, the user can hear the sound of the external environment after steady-state noise is reduced; if the third audio signal also includes the playback audio, the user can hear the sound corresponding to the playback audio while also hearing the sound of the external environment after steady-state noise is reduced.

[0101] In order to enable those skilled in the art to fully understand the active noise reduction circuit in this application, several typical circuit structures are provided. Figures 16 and 17 .

[0102] Figure 16 A schematic diagram of an achievable circuit structure of an active noise reduction circuit with NICam transparency provided by an embodiment of the present invention Figure 1 , Figure 17 A schematic diagram of an achievable circuit structure of an active noise reduction circuit with NICam transparency provided by an embodiment of the present invention Figure 2 .

[0103] Assuming that the active noise reduction unit 10 includes a fixed active noise reduction circuit 101 consisting of a feedforward filter circuit 101a and a feedback filter circuit 101b, a sub-band noise reduction unit 20 and a signal output unit 30, the active noise reduction circuit composed of them is as follows: Figure 16 shown.

[0104] Assuming that the active noise reduction unit 10 includes an adaptive active noise reduction circuit 102, a sub-band noise reduction unit 20 and a signal output unit 30, the active noise reduction circuit composed of them is as follows: Figure 17 shown.

[0105] Figure 16 and Figure 17 The structure diagram of the active noise reduction circuit in a single-ear device (such as a phone, a single-ear headset, etc.) is shown. For a double-ear device (such as a double-ear headset, a wearable device, etc.), the following is used: Figure 16 or Figure 17 The two identical active noise reduction circuits shown are sufficient.

[0106] Based on the same inventive concept, an embodiment of the present invention provides an active noise reduction method with NICam transparency, see Figure 18 , the method comprising:

[0107] Step 1801: Active noise reduction is performed on the picked-up first audio signal to obtain an anti-phase audio signal having a phase opposite to that of the ambient noise.

[0108] This can be achieved in the following ways:

[0109] The first audio signal is compensated using a third audio signal to eliminate the third audio signal contained in the first audio signal, thereby obtaining a compensated audio signal. Fixed active noise reduction or adaptive active noise reduction is then performed on the compensated audio signal to obtain an inverted audio signal. Fixed active noise reduction includes one or both of feedforward filtering and feedback filtering. For detailed implementation details, please refer to the implementation details in the active noise reduction circuit and will not be further described here.

[0110] Step 1802: performing sub-band noise reduction on a second audio signal picked up from an external environment to obtain a third audio signal after the steady-state noise of the external environment is reduced; wherein the first audio signal and the second audio signal are picked up simultaneously.

[0111] In one possible implementation, when the first audio signal includes a sub-audio signal picked up from an external environment, the sub-audio signal is downsampled to obtain a second audio signal; and sub-band noise reduction is performed on the second audio signal to obtain a third audio signal.

[0112] When the first audio signal includes a sub-audio signal picked up from an external environment, downsampling the sub-audio signal to obtain the second audio signal can implement multiplexing of the sub-audio signal and reduce circuit overhead.

[0113] The third audio signal may also include playback audio. For specific implementation methods, please refer to the relevant solutions in the active noise reduction circuit, which will not be described in detail here.

[0114] Step 1803: modulate the inverted audio signal and the third audio signal to obtain a fourth audio signal after noise reduction.

[0115] In the embodiments provided by the present invention, active noise reduction is performed on a first audio signal picked up to obtain an inverted audio signal with a phase opposite to the ambient noise; sub-band noise reduction is performed on a second audio signal picked up from the external environment to obtain a third audio signal after steady-state sound sources in the external environment are reduced; and the inverted audio signal is modulated with the third audio signal to obtain a fourth audio signal after noise reduction. The first and second audio signals are picked up simultaneously. This allows the user to clearly hear the sound of the external environment after steady-state noise reduction when listening to the fourth audio signal, giving the device using this method a clear and transparent sound quality.

[0116] Based on the same inventive concept, an embodiment of the present invention provides an electronic device, which includes an active noise reduction circuit with NICam transparency.

[0117] The electronic device may be, for example, a single-ear headset, a dual-ear headset, a phone, a wearable device, or the like.

[0118] Based on the same inventive concept, an embodiment of the present invention further provides a readable storage medium, comprising:

[0119] Memory,

[0120] The memory is used to store instructions. When the instructions are executed by the processor, the device including the readable storage medium performs the active noise reduction method with NICam transparency as described above.

[0121] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, embodiments of the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, embodiments of the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0122] The embodiments of the present invention are described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0123] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0124] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0125] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. An active noise reduction circuit with NICam transparency, characterized in that: include: an active noise reduction unit, configured to perform active noise reduction on a first audio signal picked up from at least one of an external environment and an ear canal environment, thereby obtaining an anti-phase audio signal having a phase opposite to that of the ambient noise; wherein the external environment includes a steady-state sound source; and wherein the active noise reduction unit includes a compensation filter, configured to process a third audio signal and input the processed signal into the active noise reduction unit to eliminate the third audio signal from the first audio signal. a sub-band noise reduction unit, configured to perform sub-band noise reduction on the second audio signal picked up from the external environment to obtain the third audio signal after the steady-state noise of the external environment is reduced; wherein the first audio signal and the second audio signal are picked up simultaneously, and the steady-state noise is the sound generated by the steady-state sound source; a signal output unit, configured to modulate the inverted audio signal and the third audio signal to obtain and play a fourth audio signal; The signal output unit includes a sixth adder, a second upsampling circuit, a digital-to-analog conversion circuit, and a speaker connected in sequence; the sixth adder is used to superimpose the inverted audio signal and the third audio signal to obtain a superimposed signal; the second upsampling circuit is used to upsample the superimposed signal and transmit it to the digital-to-analog conversion circuit to convert it into an analog signal, and the analog signal is used as the fourth audio signal and played through the speaker; wherein, the speaker plays the sound corresponding to the inverted audio signal in the fourth audio signal to cancel the ambient noise, and the speaker plays the sound corresponding to the third audio signal in the fourth audio signal to allow the user to hear the sound of the external environment after the steady-state noise is reduced.

2. The active noise reduction circuit according to claim 1, wherein: The active noise reduction unit includes: a fixed active noise reduction circuit or an adaptive active noise reduction circuit, and the compensation filter connected between the sub-band noise reduction unit and the fixed active noise reduction circuit or the adaptive active noise reduction circuit; The fixed active noise reduction circuit uses fixed noise reduction parameters to perform active noise reduction on the first audio signal to obtain the inverted audio signal, and the adaptive active noise reduction circuit uses adaptive coefficients to perform active noise reduction on the first audio signal to obtain the inverted audio signal.

3. The active noise reduction circuit according to claim 2, wherein: The fixed active noise reduction circuit includes: A feedforward filter circuit, or the feedforward filter circuit and the feedback filter circuit; wherein the feedforward filter circuit is used to generate an inverted audio signal with a phase opposite to that of the noise in the external environment, and the feedback filter circuit is used to generate an inverted audio signal with a phase opposite to that of the noise in the ear canal environment.

4. The active noise reduction circuit according to any one of claims 1 to 3, wherein: When the first audio signal includes a sub-audio signal picked up from the external environment, the second audio signal is obtained by downsampling the sub-audio signal.

5. The active noise reduction circuit according to any one of claims 1 to 3, wherein: The sub-band noise reduction unit is further configured to superimpose the received playback audio onto the sub-band noise-reduced audio signal to obtain the third audio signal.

6. An active noise reduction method with NICam transparency, characterized in that: include: performing signal compensation on a first audio signal picked up from at least one of an external environment and an ear canal environment using a third audio signal to eliminate the third audio signal contained in the first audio signal, thereby obtaining a compensated audio signal; performing active noise reduction on the compensated audio signal to obtain an anti-phase audio signal having a phase opposite to that of the ambient noise; wherein the external environment includes a steady-state sound source; performing sub-band noise reduction on a second audio signal picked up from the external environment to obtain a third audio signal after the steady-state noise of the external environment has been reduced; wherein the first audio signal and the second audio signal are picked up simultaneously, the steady-state noise is sound generated by the steady-state sound source; and the third audio signal serves as the compensation signal; The inverted audio signal and the third audio signal are superimposed together to obtain a superimposed signal, the superimposed signal is upsampled and digital-to-analog converted to obtain an analog signal, and the analog signal is used as the fourth audio signal and played through a speaker; wherein the speaker plays the sound corresponding to the inverted audio signal in the fourth audio signal to cancel the ambient noise, and the speaker plays the sound corresponding to the third audio signal in the fourth audio signal to allow the user to hear the sound of the external environment after the steady-state noise is reduced.

7. The method according to claim 6, wherein Active noise reduction is performed on the compensated audio signal to obtain an anti-phase audio signal having a phase opposite to that of the ambient noise, comprising: Performing fixed active noise reduction or adaptive active noise reduction on the compensated audio signal to obtain the inverted audio signal; wherein the fixed active noise reduction includes one or both of feedforward filtering and feedback filtering.

8. The method according to claim 6 or 7, wherein: Performing sub-band noise reduction on a second audio signal picked up from an external environment to obtain a third audio signal after the steady-state noise of the external environment is reduced includes: When the first audio signal includes a sub-audio signal picked up from the external environment, downsampling the sub-audio signal to obtain the second audio signal; Perform sub-band noise reduction on the second audio signal to obtain the third audio signal.

9. An electronic device, characterized in that: The invention comprises the active noise reduction circuit with NICam transparency as claimed in any one of claims 1 to 5.

10. A readable storage medium, characterized in that: Including memory, The memory is used to store instructions, and when the instructions are executed by the processor, the device including the readable storage medium performs the method according to any one of claims 6 to 8.

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