Noise reduction method, device and system, electronic equipment and storage medium

Abstract

The invention provides a noise reduction method, device and system, electronic equipment and a storage medium. The method comprises the following steps: acquiring an environment noise signal and an audio signal; the audio signal comprises a first audio signal or comprises the first audio signal and a second audio signal; the first audio signal and the second audio signal are acquired through an air conduction microphone and a bone conduction microphone respectively; and based on the environmental noise signal, noise reduction is performed on the audio signal to obtain a target audio signal, so that a better noise reduction effect can be realized without complex microphone array design, the dependence of a double-microphone beam forming technology on spatial layout and sound source position is eliminated, the method and the device are suitable for equipment with limited space, the application range is widened, and the method and the device are suitable for popularization and application. And meanwhile, the noise reduction effect is optimized.

Description

Technical Field

[0001] The present invention relates to the field of signal processing technology, and in particular to a noise reduction method, device, system, electronic equipment and storage medium. Background Art

[0002] In the current audio processing field, especially in application scenarios such as speech recognition and speech interaction, the quality of sound signals is directly related to the accuracy of subsequent processing and user experience. However, during the acquisition process, sound signals are often interfered by a variety of factors, including environmental noise, the distance between the speaker and the microphone, etc. These factors together lead to a decrease in the quality of the original sound signal, which in turn affects the efficiency and effect of speech processing.

[0003] At present, noise reduction technology based on dual-microphone beamforming is mostly used to reduce noise on sound signals. Specifically, the difference between the caller's voice and the ambient noise is calculated through the configuration of a dual-microphone array, and the spacing and angle between the microphones are adjusted using the beamforming principle to achieve noise reduction. However, this solution has space limitations and requires sufficient space to install two microphone arrays, which is often difficult to achieve for compact devices and has a limited scope of application. In addition, this solution is sensitive to the location of the sound source. When the sound source is too far or too close to the microphone array, the noise reduction effect may be greatly reduced, which causes inconvenience in practical applications. Summary of the invention

[0004] The present invention provides a noise reduction method, device, system, electronic device and storage medium, which are used to solve the problems in the prior art that the noise reduction method has installation space limitations and sound source position limitations, resulting in inconvenient application and limited noise reduction effect, and achieve better noise reduction effect.

[0005] The present invention provides a noise reduction method, comprising: Acquire an ambient noise signal and an audio signal; the audio signal includes a first audio signal, or includes a first audio signal and a second audio signal; the first audio signal and the second audio signal are collected by an air conduction microphone and a bone conduction microphone respectively; Based on the environmental noise signal, the audio signal is subjected to noise reduction to obtain a target audio signal.

[0006] According to a noise reduction method provided by the present invention, the noise reduction of the audio signal is performed based on the environmental noise signal to obtain a target audio signal, including: Perform noise detection based on the environmental noise signal to obtain a noise sound pressure level; When the noise sound pressure level indicates that the environment is noisy, performing noise reduction on the first audio signal and the second audio signal to obtain a target audio signal; When the noise sound pressure level indicates that the environment is quiet, noise reduction is performed on the first audio signal to obtain a target audio signal.

[0007] According to a noise reduction method provided by the present invention, the noise reduction is performed on the first audio signal and the second audio signal to obtain a target audio signal, including: Performing high-pass filtering on the first audio signal to obtain a first target signal; Performing low-pass filtering on the second audio signal to obtain a second target signal; The first target signal and the second target signal are subjected to analog mixing to obtain a target audio signal.

[0008] According to a noise reduction method provided by the present invention, the low-pass filtering of the second audio signal to obtain the second target signal includes: Performing signal enhancement on the second audio signal to obtain a second enhanced signal; The second enhanced signal is low-pass filtered to obtain a second target signal.

[0009] According to a noise reduction method provided by the present invention, the noise reduction of the first audio signal to obtain a target audio signal includes: The first audio signal is differentially amplified to obtain a target audio signal.

[0010] According to a noise reduction method provided by the present invention, the noise detection is performed based on the environmental noise signal to obtain the noise sound pressure level, including: Performing amplitude analysis based on the environmental noise signal to obtain a signal level in decibels; Sound pressure detection is performed based on the signal level decibel to obtain the noise sound pressure level.

[0011] The present invention also provides a noise reduction device, comprising: An acquisition unit, configured to acquire an ambient noise signal and an audio signal; the audio signal includes a first audio signal, or includes a first audio signal and a second audio signal; the first audio signal and the second audio signal are acquired by an air conduction microphone and a bone conduction microphone, respectively; The noise reduction unit is used to perform noise reduction on the audio signal based on the environmental noise signal to obtain a target audio signal.

[0012] The present invention also provides a noise reduction system, comprising a noise collection module, an air conduction microphone, a bone conduction microphone, a noise reduction module, an analog switch and a processor; The noise collection module is connected to the processor, the air conduction microphone and the bone conduction microphone are respectively connected to the noise reduction module, and the noise reduction module is connected to the processor through the analog switch; The processor is used to obtain the environmental noise signal and the audio signal collected by the noise collection module, and based on the environmental noise signal, control the noise reduction module to reduce the noise of the audio signal to obtain a target audio signal; The audio signal includes a first audio signal collected by the air conduction microphone, or includes a first audio signal collected by the air conduction microphone and a second audio signal collected by the bone conduction microphone.

[0013] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor implements any of the above-described noise reduction methods when executing the computer program.

[0014] The present invention also provides a non-transitory computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the noise reduction method as described above is implemented.

[0015] The noise reduction method, device, system, electronic device and storage medium provided by the present invention perform noise reduction on an audio signal based on an ambient noise signal to obtain a target audio signal, wherein the audio signal includes a first audio signal, or includes a first audio signal and a second audio signal; the first audio signal and the second audio signal are collected by an air conduction microphone and a bone conduction microphone respectively; the sound signal conducted by the bone is captured by the bone conduction microphone, combined with the air conduction sound signal picked up by the air conduction microphone, and under the guidance of the ambient noise signal, the difference and complementarity between the two are utilized to achieve a more efficient and flexible noise reduction effect, and a better noise reduction effect can be achieved without a complex microphone array design, and the dependence of dual-microphone beamforming technology on spatial layout and sound source position is eliminated. The method is suitable for space-constrained devices, which broadens the scope of application and optimizes the noise reduction effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 It is a schematic flow chart of the noise reduction method provided by the present invention; Figure 2 is a structural example diagram of the noise reduction system provided by the present invention; Figure 3 is an example diagram of a differential circuit provided by the present invention; Figure 4is an example diagram of an operational amplifier provided by the present invention; Figure 5 is an example diagram of a low-pass filter provided by the present invention; Figure 6 is an example diagram of a high-pass filter provided by the present invention; Figure 7 is an example diagram of an adder provided by the present invention; Figure 8 is an example diagram of an analog switch provided by the present invention; Fig. 9 It is a structural schematic diagram of the noise reduction device provided by the present invention; Fig.10 It is a structural schematic diagram of the noise reduction system provided by the present invention; Fig.11 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] At present, in the current audio processing field, the commonly used noise reduction technology based on dual-microphone beamforming is to accurately calculate the difference between the caller's voice and the ambient noise through the configuration of a dual-microphone array, and use the beamforming principle to adjust the spacing and angle between the microphones so that the effective signals are mutually reinforced, while the noise signal is relatively weakened, thereby achieving a significant noise reduction effect. Especially in complex environments such as subways and shopping malls, this technology can significantly improve the clarity of calls.

[0020] However, the noise reduction technology based on dual-microphone beamforming has its inherent limitations, which are mainly reflected in the following two aspects: First, the solution has high space requirements and requires sufficient space to install two microphone arrays, which is often difficult to achieve for compact devices such as headphones and hearing aids, so its application range is limited. Second, the solution is sensitive to the location of the sound source. When the sound source is too far or too close to the microphone array, the noise reduction effect is not very good, which is inconvenient for practical application.

[0021] In this regard, the present invention provides a noise reduction method, which is a combined noise reduction method that combines a bone conduction microphone with an air conduction microphone. The method can get rid of the dependence of dual-microphone beamforming technology on spatial layout, and does not require the design of a complex microphone array for noise reduction. It is more suitable for devices with limited space. Moreover, it is not sensitive to the position of the sound source, can achieve flexible and efficient noise reduction, and has an excellent noise reduction effect.

[0022] Figure 1 It is a flow chart of the noise reduction method provided by the present invention, such as Figure 1 As shown, the method can be applied to a noise reduction system. The method comprises: Step 110, obtaining an ambient noise signal and an audio signal; the audio signal includes a first audio signal, or includes a first audio signal and a second audio signal; the first audio signal and the second audio signal are collected by an air conduction microphone and a bone conduction microphone respectively; Step 120: based on the environmental noise signal, reduce the noise of the audio signal to obtain a target audio signal.

[0023] Specifically, considering that the dual-microphone beamforming technology currently used has obvious spatial limitations and sound source position limitations, is not very "friendly" to small and compact devices, and has limited noise reduction effects and is inconvenient in practical applications, in an embodiment of the present invention, a combined noise reduction solution that combines a bone conduction microphone with a traditional air conduction microphone is proposed. The bone conduction microphone captures the sound signal conducted by the bone, and combines it with the air conduction sound signal picked up by the air conduction microphone. Under the guidance of the ambient noise signal, the difference and complementarity between the two are utilized to achieve a more efficient and flexible noise reduction effect, thereby avoiding dependence on spatial layout and sound source position and improving practicality.

[0024] It is understandable that in actual application, before noise reduction is performed, the first thing to be acquired is the sound signal to be noise reduced, that is, the audio signal to be noise reduced. Considering the current problems with dual-microphone beamforming technology, in the embodiment of the present invention, the noise reduction system uses bone conduction combined with air conduction to collect signals. Since the bone conduction microphone uses the human bone structure to transmit sound signals, it has a higher signal-to-noise ratio and lower background noise. Signal collection based on this can effectively improve the clarity and stability of sound pickup.

[0025] Specifically, the signal can be collected by the bone conduction microphone and the air conduction microphone in the noise reduction system respectively, so as to obtain the collected audio signal. It should be noted that under different environmental noises, the conduction conditions of the lines in the noise reduction system are different, and the air conduction microphone line and the bone conduction microphone line are not both connected in all cases. Therefore, the audio signal received by the processor of the noise reduction system does not necessarily include both the first audio signal collected by the air conduction microphone and the second audio signal collected by the bone conduction microphone, but may only include the first audio signal collected by the air conduction microphone. The reason for such a setting is that when in a relatively quiet environment, the background noise is small, and it is relatively easy to collect effective sound signals at this time. Therefore, the air conduction microphone based on the air conduction principle can be directly used for signal collection, and the collected first audio signal is used as the audio signal; on the contrary, when in a relatively noisy environment, the background noise is obvious at this time, and it is necessary to combine the bone conduction microphone for signal collection. Unlike the air conduction microphone, the bone conduction microphone can automatically filter the surrounding background noise and provide an effective sound signal. Therefore, in this case, the first audio signal and the second audio signal are used as audio signals, so that the best audio signal can be obtained in different environments.

[0026] Furthermore, after obtaining the environmental noise signal and the audio signal, in the embodiment of the present invention, noise reduction can be performed accordingly to obtain the audio signal after noise reduction, that is, the target audio signal. Here, specifically, the audio signal collected by the microphone is noise-reduced based on the environmental noise signal to obtain the target audio signal. That is, the processor in the noise reduction system controls the conduction of the line in the system according to the size of the environmental noise reflected by the received environmental noise signal, the type of the current environment, etc., so that the audio signal collected by the microphone on the corresponding line can flow in the specified direction, so as to be noise-reduced by the devices in the line / pathway, and finally the audio signal after noise reduction processing can be received. Here, the noise reduction of the audio signal can be done in one step or in steps, and the embodiment of the present invention does not specifically limit this.

[0027] For example, for a noisy environment, the first audio signal and the second audio signal can be directly denoised by a filter, or the first audio signal and the second audio signal can be differentially amplified first, and then the amplified signals can be filtered and denoised, or after differential amplification, computational amplification can be performed again, and the secondary amplified signal can be filtered and denoised. For another example, for a quiet environment, the first audio signal can be differentially amplified directly, and processed by a differential amplifier circuit to eliminate common-mode noise interference, thereby achieving signal enhancement and noise reduction; or the first audio signal can be differentially amplified first, and then the amplified signal can be filtered and denoised.

[0028] In an embodiment of the present invention, the audio signal is denoised based on the environmental noise signal. The received audio signal can be flexibly adjusted and denoised according to the environment. Noise reduction can be achieved without designing a complex microphone array. It can be applicable to space-constrained devices and can obtain the best audio signal in different environments.

[0029] The noise reduction method provided by the present invention performs noise reduction on an audio signal based on an environmental noise signal to obtain a target audio signal, wherein the audio signal includes a first audio signal, or includes a first audio signal and a second audio signal; the first audio signal and the second audio signal are respectively collected by an air conduction microphone and a bone conduction microphone; the sound signal conducted by the bone is captured by the bone conduction microphone, combined with the air conduction sound signal picked up by the air conduction microphone, and under the guidance of the environmental noise signal, the difference and complementarity between the two are utilized to achieve a more efficient and flexible noise reduction effect, and a better noise reduction effect can be achieved without a complex microphone array design, and the dependence of dual-microphone beamforming technology on spatial layout and sound source position is eliminated, so that the method is suitable for space-constrained devices, the scope of application is broadened, and the noise reduction effect is optimized at the same time.

[0030] Based on the above embodiment, step 120 includes: Perform noise detection based on the environmental noise signal to obtain the noise sound pressure level; When the noise sound pressure level indicates that the environment is noisy, the first audio signal and the second audio signal are subjected to noise reduction to obtain a target audio signal; When the noise sound pressure level indicates that the environment is quiet, noise reduction is performed on the first audio signal to obtain a target audio signal.

[0031] Specifically, in step 120, the process of performing noise reduction on the audio signal according to the ambient noise signal to obtain the target audio signal may specifically include: First, noise detection can be performed based on the ambient noise signal to determine the ambient noise level of the current environment, which can be represented by the sound pressure level of the specific ambient noise; that is, noise detection is performed using the ambient noise signal to analyze the waveform, amplitude, phase, etc. of the ambient noise signal, so as to calculate the sound pressure level of the ambient noise in the current environment based on the analyzed information, that is, the noise sound pressure level.

[0032] Next, the audio signal can be de-noised according to the ambient noise sound pressure level. The de-noising process here can be divided into two cases: First, when the noise sound pressure level reflects that the current environment is noisy, that is, the current environment is a relatively noisy environment, at this time, the audio signals received by the noise reduction system are the first audio signal and the second audio signal. Therefore, the first audio signal and the second audio signal can be denoised, and the denoised audio signals can be fused to obtain the target audio signal.

[0033] Second, when the noise sound pressure level reflects that the current environment is quiet, that is, the current environment is a relatively quiet environment, at this time, the audio signal received by the noise reduction system is only the first audio signal collected by the air conduction microphone. Therefore, the first audio signal is denoised, and the first audio signal after denoising can be used as the target audio signal.

[0034] The noisy environment and the quiet environment are determined by comparing the noise sound pressure level with the preset tolerable sound pressure level threshold of the ambient noise. Specifically, when the noise sound pressure level is greater than the sound pressure level threshold, it is determined that the current environment is noisy, and vice versa, when the noise sound pressure level is less than or equal to the sound pressure level threshold, it is determined that the current environment is quiet. The sound pressure level threshold can be set according to actual conditions.

[0035] In an embodiment of the present invention, the noise sound pressure level is determined by an environmental noise signal. When in a quiet environment, a first audio signal is obtained and noise reduction is performed on it. When in a noisy environment, a first audio signal and a second audio signal are obtained and noise reduction is performed on them to obtain a target audio signal. The best audio signal can be obtained in different environments.

[0036] Based on the above embodiment, the first audio signal and the second audio signal are subjected to noise reduction to obtain a target audio signal, including: Performing high-pass filtering on the first audio signal to obtain a first target signal; Performing low-pass filtering on the second audio signal to obtain a second target signal; The first target signal and the second target signal are subjected to analog mixing to obtain a target audio signal.

[0037] Specifically, the process of performing noise reduction on the first audio signal and the second audio signal to obtain the target audio signal specifically includes the following steps: Since most of the environmental noise is a low-frequency signal, and the air conduction microphone picks up the sound signal conducted by the air, and the bone conduction microphone picks up the sound signal of the skull vibration and can automatically filter the sound in the surrounding air, therefore, in the embodiment of the present invention, the sound signal conducted by the air can be low-frequency filtered to filter out the low-frequency components therein, and the sound signal conducted by the bone can be high-frequency filtered to filter out the high-frequency components therein. In this way, the filtering of environmental noise is achieved and the noise is effectively reduced.

[0038] Specifically, here, the first audio signal may be subjected to high-pass filtering to filter out high-frequency components and filter out low-frequency components, thereby obtaining a filtered first audio signal, i.e., a first target signal. Here, high-pass filtering may be implemented by a high-pass filter, specifically, a second-order passive high-pass filter may be used to perform high-pass filtering to filter out signals below the high-pass cutoff frequency and retain signals above the high-pass cutoff frequency. At the same time, the second audio signal may be subjected to low-pass filtering to filter out low-frequency components and filter out high-frequency components, thereby obtaining a filtered second audio signal, i.e., a second target signal. Here, low-pass filtering may be implemented by a low-pass filter, specifically, a second-order passive low-pass filter may be used to perform low-pass filtering to filter out signals above the low-pass cutoff frequency and retain signals below the low-pass cutoff frequency.

[0039] After that, the target audio signal can be determined according to the first target signal and the second target signal. Here, the first audio signal and the second audio signal are specifically simulated mixed to obtain a complete audio signal after filtering and noise reduction. Considering the signal delay and signal distortion problems that may occur during the signal processing, in an embodiment of the present invention, an adder is used for analog mixing, specifically, the operational amplifier is designed as an adder, and a mixing operation is performed by the adder to obtain a mixed audio signal, that is, a target audio signal.

[0040] Compared with the traditional dual-microphone beamforming technology, which introduces a certain delay in the analysis and processing of audio signals, making it unsuitable for scenarios with high requirements on delay, in the embodiment of the present invention, analog mixing is performed through an adder, without additional digital distortion and algorithm processing delay, and the noise-reduced audio signal can be obtained more quickly and accurately.

[0041] In an embodiment of the present invention, in a noisy environment, a bone conduction microphone provides signals in the medium and low frequency bands, an air conduction microphone provides signals in the high frequency bands, and the two are combined through an adder, which can effectively remove the ambient noise in the noisy environment and achieve a strong noise reduction effect, thereby providing high-quality data for subsequent voice interactions, voice calls, etc.

[0042] Based on the above embodiment, low-pass filtering is performed on the second audio signal to obtain a second target signal, including: Performing signal enhancement on the second audio signal to obtain a second enhanced signal; The second enhanced signal is low-pass filtered to obtain a second target signal.

[0043] Specifically, when the second audio signal is low-pass filtered to obtain the second target signal, considering that the amplitude of the electrical signal converted by the bone conduction microphone through skull vibration is relatively small, it is not convenient for subsequent noise reduction processing. Therefore, it can be pre-amplified here. That is, the second audio signal is amplified by an operational amplifier to achieve signal enhancement, which is specifically reflected in increasing the dynamic range of the signal and suppressing noise, thereby obtaining an enhanced second audio signal, that is, a second enhanced signal.

[0044] After that, the second enhanced signal can be low-pass filtered to filter out high-frequency components to obtain a filtered second enhanced signal, that is, a second target signal. The process of low-pass filtering has been described in detail above and will not be repeated here.

[0045] Based on the above embodiment, the first audio signal is subjected to noise reduction to obtain a target audio signal, including: The first audio signal is differentially amplified to obtain a target audio signal.

[0046] Specifically, the above-mentioned process of performing noise reduction on the first audio signal to obtain the target audio signal can be specifically that, since the air conduction microphone collects signals based on air conduction, the first audio signal collected thereby will inevitably contain noise components. Therefore, the first audio signal can be differentially amplified by a differential circuit here to eliminate part of the common-mode noise interference and improve the anti-interference performance of the signal, and finally the first audio signal after differential amplification, i.e., the target audio signal, can be obtained.

[0047] It should be noted that compared with other circuit designs and noise reduction methods, at the same input level, the differential circuit can amplify a larger dynamic range of the differential signal, improve the clarity of the audio signal, make the details more obvious, and obtain a clearer and more accurate audio signal.

[0048] Based on the above embodiment, noise detection is performed based on the environmental noise signal to obtain the noise sound pressure level, including: Perform amplitude analysis based on the environmental noise signal to obtain the signal level in decibels; The sound pressure is detected based on the signal level in decibels to obtain the noise sound pressure level.

[0049] Specifically, the process of performing noise detection according to the environmental noise signal to obtain the noise sound pressure level may specifically include: First, the waveform, amplitude, phase and other aspects of the environmental noise signal can be analyzed to determine the level amplitude (average signal level) of the environmental noise signal, that is, the signal level in decibels. Here, the amplitude value and the maximum amplitude value of the sound signal can be determined by analyzing the signal, and the signal level in decibels can be determined based on the sound amplitude value and the maximum amplitude value.

[0050] Next, sound pressure detection can be performed according to the signal level decibel to obtain the sound pressure level of the ambient noise, that is, the noise sound pressure level is obtained by comprehensive calculation according to the sensitivity of the microphone collecting the ambient noise signal and the signal level decibel.

[0051] The signal level decibel and noise sound pressure level are calculated based on the following formulas: In the formula, is the signal level in decibels, and are the amplitude value and maximum amplitude of the sound signal respectively.

[0052] The following takes a specific structure as an example to illustrate the process of signal acquisition and noise reduction of the noise reduction system: Figure 2 is a structural example diagram of the noise reduction system provided by the present invention, such as Figure 2 As shown, the system includes a noise collection module, an air conduction microphone, a bone conduction microphone, a high-pass filter, a low-pass filter, an operational amplifier, an adder, an analog switch and a processor.

[0053] The noise reduction system can control the conduction of the circuit according to the environmental noise signal collected by the noise collection module to receive the audio signal collected by the microphone and reduce the noise thereof to obtain the target audio signal. Specifically, when in a noisy environment, the analog switch outputs the signal processed by the adder to the processor, that is, the audio signal collected by the air conduction microphone and the bone conduction microphone is subjected to noise reduction and analog mixing and input to the processor. When in a quiet environment, the analog switch outputs the audio signal collected by the air conduction microphone to the processor after the noise reduction processing.

[0054] Since most of the environmental noise is a low-frequency signal, and the air conduction microphone picks up the sound signal in the air, and the bone conduction microphone picks up the sound signal of the skull vibration and automatically filters the sound in the surrounding air, therefore, in the embodiment of the present invention, the second audio signal collected by the bone conduction microphone can be low-pass filtered in a noisy environment, and the first audio signal collected by the air conduction microphone can be high-pass filtered, and then the audio signals after high and low pass are simulated mixed by the adder, and the mixed signal is input into the processor for further processing. In this way, the environmental noise can be greatly reduced in a noisy environment, and the audio signal can be clearly picked up.

[0055] In the embodiment of the present invention, the processor is mainly responsible for: The volume of the audio signal collected by the microphone is controlled through the volume adjustment module; Power the microphone and operational amplifier module through the power management module; Control the on-off logic of analog switch input and output through IO logic control interface; Through signal processing analysis algorithms and logic algorithms, the environmental noise signal is analyzed and processed to complete the noise sound pressure level calculation; Through the analog-to-digital / digital-to-analog conversion module, the external signal can be converted into analog-to-digital, and the built-in digital audio can also be converted into analog output through the digital-to-analog conversion module. It also supports direct input and output of digital signals.

[0056] The noise collection module includes a noise collection unit and a data transmission unit. The microphone in the noise collection unit (a small-sized microphone with a length, width and height of 275*185*0.9mm, a sensitivity of 24 mV / Pa, which means that it can output a voltage of 24mV at a sound pressure of 1Pa) is used to collect environmental noise and convert it into an analog electrical signal. The analog electrical signal is converted into a digital signal through analog-to-digital conversion and transmitted to the processor through the data transmission unit for analysis and processing through the signal processing analysis algorithm and logic algorithm in the processor. The algorithm parameter variables include signal waveform, time, amplitude, phase, etc. at a given frequency. Based on this, the signal level in decibels can be calculated, and the noise sound pressure level can be obtained by calculation based on the sensitivity of the microphone.

[0057] The air conduction microphone adopts a traditional electret or MEMS analog microphone. In order to eliminate the noise of the audio signal directly collected by the microphone, in the embodiment of the present invention, a differential circuit is arranged behind the microphone. Figure 3 is an example diagram of a differential circuit provided by the present invention, such as Figure 3 As shown in the figure, Micbias is powered by a processor, and the differential circuit and microphone are integrated. The differential circuit is a microphone output circuit that adopts a differential design, which can eliminate part of the common-mode noise interference in the signal and improve the anti-interference performance. Under the same input level, the differential circuit can amplify a larger dynamic range of the differential signal and improve the clarity and details of the audio.

[0058] The bone conduction microphone uses an analog MEMS bone conduction microphone, which is connected to the same differential circuit as the air conduction microphone. The bone conduction microphone uses the principle of bone conduction sound to convert sound into electrical signals by sensing skull vibrations; unlike traditional air conduction microphones, bone conduction microphones can automatically filter out surrounding environmental noise with an isolation of approximately 50dB@100Hz. It should be noted that in order to ensure that the sound signal can be accurately transmitted to the microphone, the bone conduction microphone needs to be placed close to the head. Specifically, the bone conduction microphone is usually fixed behind the ear to make close contact with the skull, so as to better sense skull vibrations to collect sound signals.

[0059] However, since the amplitude of the electrical signal converted by the bone conduction microphone through skull vibration is relatively small, it needs to be pre-amplified. Figure 4 is an example diagram of the operational amplifier provided by the present invention, such as Figure 4 As shown, the signal output by the differential circuit is amplified by an operational amplifier. By amplifying the differential signal, the dynamic range and noise suppression capability of the signal can be increased.

[0060] For an operational amplifier, the input and output calculation formula is: The operational amplifier receives the differential signal collected by the bone conduction microphone and amplified by the differential circuit, and amplifies it through the operational amplifier After multiplication, the differential output is sent to a low-pass filter.

[0061] Bone conduction microphones can pick up skull vibrations and convert vibration signals into electrical signals, which have the advantage of isolating ambient noise in the surrounding air. However, due to the different attenuation and phase delay of the skull for sound waves of different frequencies, the transmission effect of high-frequency signals is limited compared to low-frequency signals. Therefore, a low-pass filter can be set in the bone conduction microphone channel to filter out high-frequency signals, retaining only medium and low-frequency signals, and the high-frequency signals are picked up by the air conduction microphone. Finally, the air conduction and bone conduction signals are mixed into one channel, and the air conduction and bone conduction microphones perform their respective duties and complement each other. Figure 5 is an example diagram of the low-pass filter provided by the present invention, such as Figure 5 As shown, a second-order passive low-pass filter is used for low-pass filtering, and the low-pass cutoff frequency LPF=1 / (2ΠR1C1).

[0062] Figure 6 is an example diagram of the high-pass filter provided by the present invention, such as Figure 6 As shown, a second-order passive high-pass filter is used as a high-pass filter, which receives the differential signal collected by the air conduction microphone and amplified by the differential circuit, and filters it. The high-pass cutoff frequency HPF=1 / (2ΠR2C2). In order to ensure that the signal connection can be smooth when the signal from the air conduction and the signal from the bone conduction are mixed into one signal, LPF=HPF is preferably used here, and the cutoff frequency can be determined according to the performance of the microphone, for example, it can be 2000Hz.

[0063] Figure 7 is an example diagram of the adder provided by the present invention, such as Figure 7 As shown in the figure, the high-frequency signal of the air conduction microphone path and the medium-low frequency signal of the bone conduction microphone path are mixed into one signal. The principle of mixing is to design the operational amplifier as an adder to realize the A+B mixing operation. Since this method is additive analog mixing, it will not affect the delay and distortion of the signal.

[0064] Among them, A represents the low- and medium-frequency audio signal output by the low-pass filter in the bone conduction microphone path, and B represents the high-frequency signal output by the high-pass filter in the air conduction microphone path. After being processed by the adder, a mixed differential signal of bone conduction and air conduction, i.e., the target audio signal, is output, and the target audio signal can be output to the analog switch.

[0065] Figure 8 is an example diagram of the analog switch provided by the present invention, such as Figure 8 As shown in the figure, the MIC1_N and MIC1_P outputs of the differential circuit in the air conduction microphone path, and the MIC2_N and MIC2_P outputs of the adder are all given to the analog switch. SW_AMIC_CTRL is the enable signal, which is connected to the IO logic control interface of the processor, and a high level (logic 1) or a low level (logic 0) indicates enable or disable. The control logic of the analog switch can be represented by the following table:

[0066] The processor obtains the environmental noise signal through the noise acquisition module and obtains the noise sound pressure level SE through noise detection SPL , and the sound pressure level threshold TH SPL For comparison, when SE SPL Greater than TH SPL When it is determined that it is currently in a noisy environment, the IO logic control interface outputs a high level (logic 1); when SE SPL Less than or equal to TH SPL When the sound pressure level threshold TH is reached, it is determined that the current environment is quiet, and the IO logic control interface outputs a low level (logic 0). SPL is 45dB.

[0067] Taking the Shengbangwei SGM3718 dual-channel single-pole double-throw analog switch as an example, the logic control process is explained: When the SW_AMIC_CTRL enable signal is low (logic 0), COM1, COM2 and ECM1_N and ECM1_P are turned on, and the analog switch outputs the signal output by the differential circuit in the air conduction microphone path to the processor. When the SW_AMIC_CTRL enable signal is high (logic 1), COM1, COM2 and ECM2_N and ECM2_P are turned on, and the analog switch outputs the signal output by the adder to the processor.

[0068] The processor includes an analog-to-digital conversion module that can convert analog signals into digital signals. The converted digital signal can be used as a near-end microphone signal in a call scenario, modulated to a high frequency, and sent to the far end for playback, or stored in a folder as a local recording audio, or used as an audio input for a wireless microphone device, or as a microphone input for voice wake-up in a high-noise scenario, and can also be used in other scenarios, which are not specifically limited in the embodiments of the present invention.

[0069] The noise reduction device provided by the present invention is described below, and the noise reduction device described below and the noise reduction method described above can be referred to each other.

[0070] Fig. 9 is a schematic diagram of the structure of the noise reduction device provided by the present invention, such as Fig. 9 As shown, the device comprises: An acquisition unit 910 is used to acquire an ambient noise signal and an audio signal; the audio signal includes a first audio signal, or includes a first audio signal and a second audio signal; the first audio signal and the second audio signal are collected by an air conduction microphone and a bone conduction microphone respectively; The noise reduction unit 920 is configured to perform noise reduction on the audio signal based on the environmental noise signal to obtain a target audio signal.

[0071] The noise reduction device provided by the present invention performs noise reduction on an audio signal based on an environmental noise signal to obtain a target audio signal, wherein the audio signal includes a first audio signal, or includes a first audio signal and a second audio signal; the first audio signal and the second audio signal are respectively collected by an air conduction microphone and a bone conduction microphone; the sound signal conducted by the bone is captured by the bone conduction microphone, combined with the air conduction sound signal picked up by the air conduction microphone, and under the guidance of the environmental noise signal, the difference and complementarity between the two are utilized to achieve a more efficient and flexible noise reduction effect, and a better noise reduction effect can be achieved without a complex microphone array design, and the dependence of dual-microphone beamforming technology on spatial layout and sound source position is eliminated, so that the device is suitable for space-constrained devices, the scope of application is broadened, and the noise reduction effect is optimized at the same time.

[0072] Based on the above embodiment, the noise reduction unit 920 is used for: Perform noise detection based on the environmental noise signal to obtain a noise sound pressure level; When the noise sound pressure level indicates that the environment is noisy, performing noise reduction on the first audio signal and the second audio signal to obtain a target audio signal; When the noise sound pressure level indicates that the environment is quiet, noise reduction is performed on the first audio signal to obtain a target audio signal.

[0073] Based on the above embodiment, the noise reduction unit 920 is used for: Performing high-pass filtering on the first audio signal to obtain a first target signal; Performing low-pass filtering on the second audio signal to obtain a second target signal; The first target signal and the second target signal are subjected to analog mixing to obtain a target audio signal.

[0074] Based on the above embodiment, the noise reduction unit 920 is used for: Performing signal enhancement on the second audio signal to obtain a second enhanced signal; The second enhanced signal is low-pass filtered to obtain a second target signal.

[0075] Based on the above embodiment, the noise reduction unit 920 is used for: The first audio signal is differentially amplified to obtain a target audio signal.

[0076] Based on the above embodiment, the noise reduction unit 920 is used for: Performing amplitude analysis based on the environmental noise signal to obtain a signal level in decibels; Sound pressure detection is performed based on the signal level decibel to obtain the noise sound pressure level.

[0077] Fig.10 is a structural schematic diagram of the noise reduction system provided by the present invention, such as Fig.10 As shown, the system includes a noise collection module 1010, an air conduction microphone 1020, a bone conduction microphone 1030, a noise reduction module 1040, an analog switch 1050 and a processor 1060; The noise collection module 1010 is connected to the processor 1060, the air conduction microphone 1020 and the bone conduction microphone 1030 are respectively connected to the noise reduction module 1040, and the noise reduction module 1040 is connected to the processor 1060 via the analog switch 1050; The processor 1060 is used to obtain the environmental noise signal and the audio signal collected by the noise collection module 1010, and control the noise reduction module 1040 to reduce the noise of the audio signal based on the environmental noise signal to obtain a target audio signal; The audio signal includes a first audio signal collected by the air conduction microphone 1020 , or includes a first audio signal collected by the air conduction microphone 1020 and a second audio signal collected by the bone conduction microphone 1030 .

[0078] The noise reduction system provided by the present invention comprises a noise collection module, an air conduction microphone, a bone conduction microphone, a noise reduction module, an analog switch and a processor; the noise collection module is connected to the processor, the air conduction microphone and the bone conduction microphone are respectively connected to the noise reduction module, and the noise reduction module is connected to the processor through the analog switch; the processor is used to obtain the environmental noise signal collected by the noise collection module and the audio signal, and based on the environmental noise signal, control the noise reduction module to perform noise reduction on the audio signal to obtain a target audio signal; the audio signal comprises a first audio signal collected by the air conduction microphone, or comprises a first audio signal collected by the air conduction microphone and a second audio signal collected by the bone conduction microphone, and noise reduction can be achieved without complex microphone array design, and the dependence of dual-microphone beamforming technology on spatial layout and sound source position is eliminated, so the system is suitable for space-constrained equipment, broadens the scope of application, and optimizes the noise reduction effect.

[0079] Fig.11 An example of a physical structure diagram of an electronic device is shown in FIG. Fig.11 As shown, the electronic device may include: a processor 1110, a communication interface 1120, a memory 1130 and a communication bus 1140, wherein the processor 1110, the communication interface 1120 and the memory 1130 communicate with each other through the communication bus 1140. The processor 1110 may call the logic instructions in the memory 1130 to execute the noise reduction method, which includes: obtaining an ambient noise signal and an audio signal; the audio signal includes a first audio signal, or includes a first audio signal and a second audio signal; the first audio signal and the second audio signal are collected by an air conduction microphone and a bone conduction microphone respectively; based on the ambient noise signal, the audio signal is denoised to obtain a target audio signal.

[0080] In addition, the logic instructions in the above-mentioned memory 1130 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0081] On the other hand, the present invention also provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the noise reduction method provided by the above-mentioned methods, and the method includes: obtaining an ambient noise signal and an audio signal; the audio signal includes a first audio signal, or includes a first audio signal and a second audio signal; the first audio signal and the second audio signal are respectively collected by an air conduction microphone and a bone conduction microphone; based on the ambient noise signal, the audio signal is denoised to obtain a target audio signal.

[0082] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, it is implemented to execute the noise reduction method provided by the above-mentioned methods, the method comprising: obtaining an ambient noise signal and an audio signal; the audio signal comprises a first audio signal, or comprises a first audio signal and a second audio signal; the first audio signal and the second audio signal are respectively collected by an air conduction microphone and a bone conduction microphone; based on the ambient noise signal, the audio signal is denoised to obtain a target audio signal.

[0083] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0084] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these 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 invention.

Claims

1. A noise reduction method, characterized in that: include: Acquire an ambient noise signal and an audio signal; the audio signal includes a first audio signal, or includes a first audio signal and a second audio signal; the first audio signal and the second audio signal are collected by an air conduction microphone and a bone conduction microphone respectively; Based on the environmental noise signal, the audio signal is subjected to noise reduction to obtain a target audio signal.

2. The noise reduction method according to claim 1, characterized in that: The step of reducing the noise of the audio signal based on the environmental noise signal to obtain a target audio signal includes: Perform noise detection based on the environmental noise signal to obtain a noise sound pressure level; When the noise sound pressure level indicates that the environment is noisy, performing noise reduction on the first audio signal and the second audio signal to obtain a target audio signal; When the noise sound pressure level indicates that the environment is quiet, noise reduction is performed on the first audio signal to obtain a target audio signal.

3. The noise reduction method according to claim 2, characterized in that: The performing noise reduction on the first audio signal and the second audio signal to obtain a target audio signal includes: Performing high-pass filtering on the first audio signal to obtain a first target signal; Performing low-pass filtering on the second audio signal to obtain a second target signal; The first target signal and the second target signal are subjected to analog mixing to obtain a target audio signal.

4. The noise reduction method according to claim 2, characterized in that: The low-pass filtering the second audio signal to obtain a second target signal includes: Performing signal enhancement on the second audio signal to obtain a second enhanced signal; The second enhanced signal is low-pass filtered to obtain a second target signal.

5. The noise reduction method according to claim 2, characterized in that: The step of performing noise reduction on the first audio signal to obtain a target audio signal includes: The first audio signal is differentially amplified to obtain a target audio signal.

6. The noise reduction method according to any one of claims 2 to 5, characterized in that: The performing noise detection based on the environmental noise signal to obtain the noise sound pressure level includes: Performing amplitude analysis based on the environmental noise signal to obtain a signal level in decibels; Sound pressure detection is performed based on the signal level decibel to obtain the noise sound pressure level.

7. A noise reduction device, characterized in that: include: An acquisition unit, configured to acquire an ambient noise signal and an audio signal; the audio signal includes a first audio signal, or includes a first audio signal and a second audio signal; the first audio signal and the second audio signal are acquired by an air conduction microphone and a bone conduction microphone, respectively; The noise reduction unit is used to perform noise reduction on the audio signal based on the environmental noise signal to obtain a target audio signal.

8. A noise reduction system, characterized in that: Including noise collection module, air conduction microphone, bone conduction microphone, noise reduction module, analog switch and processor; The noise collection module is connected to the processor, the air conduction microphone and the bone conduction microphone are respectively connected to the noise reduction module, and the noise reduction module is connected to the processor through the analog switch; The processor is used to obtain the environmental noise signal and the audio signal collected by the noise collection module, and based on the environmental noise signal, control the noise reduction module to reduce the noise of the audio signal to obtain a target audio signal; The audio signal includes a first audio signal collected by the air conduction microphone, or includes a first audio signal collected by the air conduction microphone and a second audio signal collected by the bone conduction microphone.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the noise reduction method according to any one of claims 1 to 6 is implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the noise reduction method according to any one of claims 1 to 6 is implemented.

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