CN113707121A - Active noise reduction system, method and device - Google Patents

Active noise reduction system, method and device Download PDF

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Publication number
CN113707121A
CN113707121A CN202110883176.6A CN202110883176A CN113707121A CN 113707121 A CN113707121 A CN 113707121A CN 202110883176 A CN202110883176 A CN 202110883176A CN 113707121 A CN113707121 A CN 113707121A
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signal
sound signal
noise
microphone
audio processing
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蔡正辉
苏辉
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Hangzhou Ezviz Network Co Ltd
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Hangzhou Ezviz Network Co Ltd
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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1785—Methods, e.g. algorithms; Devices
    • G10K11/17853—Methods, e.g. algorithms; Devices of the filter
    • G10K11/17854—Methods, e.g. algorithms; Devices of the filter the filter being an adaptive filter
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1787—General system configurations
    • G10K11/17879—General system configurations using both a reference signal and an error signal
    • G10K11/17881—General system configurations using both a reference signal and an error signal the reference signal being an acoustic signal, e.g. recorded with a microphone
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/30—Means
    • G10K2210/301—Computational
    • G10K2210/3026—Feedback
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/30—Means
    • G10K2210/301—Computational
    • G10K2210/3028—Filtering, e.g. Kalman filters or special analogue or digital filters

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)
  • Circuit For Audible Band Transducer (AREA)

Abstract

The embodiment of the application provides an active noise reduction system, a method and a device, wherein the active noise reduction system comprises a noise control branch circuit, and the method comprises the following steps: the system comprises an audio processing device, a first microphone wirelessly connected with the audio processing device, and a loudspeaker in communication connection with the audio processing device; the first microphone is used for collecting noise signals and sending the noise signals to the audio processing equipment through wireless connection; the audio processing equipment is used for generating an inverse sound signal according to the noise signal and the signal processing parameter and sending the inverse sound signal to the loudspeaker after preset delay time; the residual sound signal after the phase-reversed sound signal and the noise signal are mutually offset is not greater than the sound signal threshold; the loudspeaker is used for playing the inverse sound signal. Therefore, the signal transmission time of the first microphone and the audio processing equipment is obviously shortened through wireless connection, and the inverted sound signal and the noise signal are mutually offset through delaying and sending the inverted sound signal, so that the noise reduction effect of an open type or a semi-open type area can be improved.

Description

Active noise reduction system, method and device
Technical Field
The present application relates to the field of active noise reduction, and in particular, to an active noise reduction system, method and apparatus.
Background
In a daily office or home scenario, sometimes a person is located in an area that may be an open or semi-open specific area, such as a conference room with a semi-open door or a room with an open door. Sometimes people forget to close the door, follow-up meetings or carers the child to sleep and are inconvenient to close the door, and the specific areas are easily interfered by noise outside the specific areas.
Therefore, for an open or semi-open specific area, there is a problem how to perform active noise reduction to avoid noise outside the specific area from interfering with people in the specific area.
Disclosure of Invention
An object of the embodiments of the present application is to provide an active noise reduction system, method and device, so as to solve the problem of how to reduce noise in an open or semi-open area.
In order to solve the above technical problem, the embodiment of the present application is implemented as follows:
in a first aspect, an embodiment of the present application provides an active noise reduction system, including at least one noise control branch, where the noise control branch includes: the system comprises an audio processing device, a first microphone wirelessly connected with the audio processing device and a loudspeaker in communication connection with the audio processing device;
the first microphone is used for acquiring a noise signal and transmitting the noise signal to the audio processing equipment through wireless connection;
the audio processing equipment is used for generating an inverse sound signal according to the noise signal and the currently stored signal processing parameter and sending the inverse sound signal to the loudspeaker after the preset delay time; the residual sound signal after the phase-reversed sound signal and the noise signal are mutually offset is not greater than a preset sound signal threshold value;
and the loudspeaker is used for playing the inverse sound signal.
In a second aspect, an active noise reduction method is provided in an active noise reduction system, where the active noise reduction system includes at least one noise control branch, where the noise control branch includes an audio processing device, a first microphone wirelessly connected to the audio processing device, and a speaker communicatively connected to the audio processing device; the method comprises the following steps:
acquiring a noise signal acquired by a first microphone through wireless connection;
generating an inverse sound signal according to the noise signal and the currently stored signal processing parameters;
sending the reversed-phase sound signal to a loudspeaker after a preset delay time so that the loudspeaker plays the reversed-phase sound signal; and the residual sound signal after the phase-reversed sound signal and the noise signal are mutually offset is not greater than a preset sound signal threshold value.
In a third aspect, an active noise reduction apparatus is provided in an embodiment of the present application, and is applied to an active noise reduction system, where the active noise reduction system includes at least one noise control branch, where the noise control branch includes a first microphone and a speaker; the device comprises:
a memory for storing signal processing parameters;
the processor is used for acquiring a noise signal acquired by the first microphone through wireless connection; generating an inverse sound signal according to the noise signal and the currently stored signal processing parameters; sending the reversed-phase sound signal to a loudspeaker after a preset delay time so that the loudspeaker plays the reversed-phase sound signal; and the residual sound signal after the phase-reversed sound signal and the noise signal are mutually offset is not greater than a preset sound signal threshold value.
In a fourth aspect, an embodiment of the present application provides an electronic device, including: a processor, a communication interface, a memory, and a communication bus; the processor, the communication interface and the memory complete mutual communication through a bus; a memory for storing a computer program; and the processor is used for executing the program stored in the memory and realizing the steps of the active noise reduction method of the second aspect.
In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the steps of the active noise reduction method of the second aspect.
In an embodiment of the present description, an active noise reduction system includes at least one noise control branch, the noise control branch including: the system comprises an audio processing device, a first microphone wirelessly connected with the audio processing device and a loudspeaker in communication connection with the audio processing device; the first microphone is used for acquiring a noise signal and transmitting the noise signal to the audio processing equipment through wireless connection; the audio processing equipment is used for generating an inverse sound signal according to the noise signal and the currently stored signal processing parameter and sending the inverse sound signal to the loudspeaker after the preset delay time; the residual sound signal after the phase-reversed sound signal and the noise signal are mutually offset is not greater than a preset sound signal threshold value; and the loudspeaker is used for playing the inverse sound signal. Therefore, the noise signal is transmitted between the first microphone and the audio processing device through wireless connection, transmission delay of the noise signal between the first microphone and the audio processing device can be reduced based on the characteristic of wireless transmission, the problems of signal phase mismatch and the like caused by large transmission delay are avoided, and the processing rate of the noise signal is improved. The reverse sound signal played by the loudspeaker can be mutually offset with the noise signal propagated in the air by sending the reverse sound signal after the preset delay time; for an open or semi-open area, noise signals can be prevented from being transmitted to the area and causing adverse effects on personnel in the area, and therefore noise reduction of the open or semi-open area is achieved.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without any creative effort.
Fig. 1 is a schematic view of a first structure of an active noise reduction system provided in an embodiment of the present disclosure;
fig. 2 is a schematic diagram of a second structure of an active noise reduction system provided in the embodiments of the present disclosure;
fig. 3 is a schematic structural diagram of a third active noise reduction system provided in the embodiments of the present disclosure;
fig. 4 is a timeline diagram of an active noise reduction system through wired transmission according to an embodiment of the present disclosure;
fig. 5 is a timeline diagram of an active noise reduction system through wireless transmission according to an embodiment of the present disclosure;
FIG. 6 is a schematic diagram of an open office space provided by an embodiment of the present disclosure;
fig. 7 is a schematic diagram of a fourth structure of an active noise reduction system provided in the embodiments of the present disclosure;
fig. 8 is a schematic diagram of an open conference room provided in an embodiment of the present disclosure;
fig. 9 is a schematic flowchart of an active noise reduction method provided in an embodiment of the present disclosure;
fig. 10 is a schematic diagram illustrating a module composition of an active noise reduction apparatus provided in an embodiment of the present disclosure;
fig. 11 is a schematic composition diagram of an electronic device provided in an embodiment of the present specification.
Detailed Description
In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In traditional scenes such as office, meeting and house, sound insulation effect is usually realized by adopting a wall structure, for example, in a closed meeting room, the wall structure around the meeting room is built by utilizing building materials with good sound insulation effect and a construction mode so as to isolate outdoor noise from being transmitted to the meeting room, and avoid that personnel in the meeting room are interfered by noise outside the meeting room.
The open conference room is taken as an example for explanation, the open conference room has a new structure of wall-free office, so that the distances between employees and leaders are reduced, and the conference efficiency can be improved. In addition, compared with the traditional closed meeting room, the open meeting room reduces the required office area and saves the construction cost. However, open meeting room can't give sound insulation between meeting indoor space and meeting outdoor space hardly, lacks wall structure's separation and has led to meeting outdoor space's noise to propagate to meeting indoor space very easily, and then causes the office staff in the meeting room to receive noise interference, reduces work efficiency.
Therefore, in open office, meeting, home and other scenes, in order to avoid that people in an open or semi-open area are interfered by noise outside the area, the embodiment of the present specification provides an active noise reduction system.
Fig. 1 is a schematic structural diagram of a first active noise reduction system provided in an embodiment of the present disclosure.
Referring to fig. 1, the active noise reduction system includes at least one noise control branch 102 (only one shown in fig. 1), and noise control branch 102 includes: an audio processing device 1024, a first microphone 1022 wirelessly connected to the audio processing device 1024, and a speaker 1026 communicatively connected to the audio processing device 1024.
The first microphone 1022 is configured to collect a noise signal and transmit the noise signal to the audio processing device 1024 via a wireless connection.
The audio processing device 1024 is configured to generate an inverse sound signal according to the noise signal and the currently stored signal processing parameter, and send the inverse sound signal to the speaker 1026 after a preset delay time; and the residual sound signal after the phase-reversed sound signal and the noise signal are mutually offset is not greater than a preset sound signal threshold value.
A speaker 1026 for playing the inverted sound signal.
The first microphone 1022 may be an analog microphone or a digital microphone.
The noise signal may be a noise signal outside a designated noise reduction area where noise reduction requirements exist, for example, a job discussion sound in an office area outside an open conference room. The noise signal may be a voice of a person speaking, a voice of moving an object, or a voice of audio software or video software played by an electronic device, and the description does not specially limit the type of the noise signal.
The audio processing device 1024 may be a DSP (Digital Signal processing) module, a processor with a Digital Signal processing function, or a device with a Digital Signal processing function (e.g., a terminal device such as a desktop computer, a server, or the like). The audio processing device 1024 has stored therein signal processing parameters. The signal processing parameters are used to process the sound signals received by the audio processing device 1024.
The audio processing device 1024 may be in wireless communication with the first microphone 1022. The audio processing device 1024 may be connected in wireless communication with the speaker 1026 or may be connected in wired communication.
The wireless connection between the first microphone 1022 and the audio processing device 1024 may be any one or more of bluetooth, NFC (Near Field Communication), WIFI, and the like. For example, a bluetooth module is disposed in the first microphone 1022, a bluetooth module is disposed in the audio processing device 1024, and a noise signal is transmitted between the first microphone 1022 and the audio processing device 1024 through a bluetooth connection; for another example, the first microphone 1022 and the audio processing device 1024 are both connected to a router, and a noise signal is transmitted between the first microphone 1022 and the audio processing device 1024 through a WIFI connection. In this application, the wireless connection mode between the first microphone 1022 and the audio processing device 1024 is not specifically limited, and may be set in practical applications as needed.
Optionally, the signal processing parameters include filter weights; the audio processing device 1024 is specifically configured to: generating an intermediate sound signal according to the noise signal and the filter weight; the intermediate audio signal is processed in reverse to generate a reverse audio signal.
In general, there is instability in the voice of a person speaking, and the voice greatly fluctuates depending on the content, emotion, and the like. Therefore, no matter the first microphone collects only one person speaking voice, or collects the voice mixed by the voices of a plurality of persons speaking, or collects the voice mixed by the voices of the persons speaking and other voices, the collected noise signal has instability, and is difficult to express through a fixed mathematical formula, and further difficult to expressSo as to directly perform an inversion process on the noise signal. In the embodiment of the present application, the audio processing device 1024 stores signal processing parameters, where the signal processing parameters include a filter weight hAF(t) of (d). Filter weight hAF(t) for processing the noise signal to obtain an intermediate sound signal, which may be represented by an approximate mathematical expression, and the audio processing device 1024 performs an inverse phase processing on the intermediate sound signal to obtain an inverse sound signal, which implements the mathematical expression of the sound signal.
Assuming that the noise signal is x (t), x (t) is input to the audio processing apparatus 1024, and the audio processing apparatus 1024 calculates the inverse sound signal b (t) by the following formula.
b(t)＝-hAF(t)*x(t) (1)
When the active noise reduction system starts, the filter weight h stored in the audio processing device 1024AF(t) may be a fixed value that is preset empirically. In the subsequent steps, the filter weight hAF(t) may be adaptively adjusted through feedback.
And the residual sound signal after the phase-reversed sound signal and the noise signal are mutually offset is not greater than a preset sound signal threshold value. Considering theoretical values, the active noise reduction system expects to completely cancel the inverse sound signal and the noise signal, i.e., the residual sound signal takes a value of 0. However, in the actual operation process, the probability of complete cancellation is low, and when the value of the residual sound signal is not greater than the preset sound signal threshold, the human ear can hardly perceive the residual sound signal, so that when the residual sound signal is not greater than the preset sound signal threshold, the active noise reduction system can also achieve a good sound cancellation effect, and further avoid the interference of receiving the noise signal outside the area inside the open type or semi-open type area.
Optionally, the noise control branch further comprises: a second microphone 1028 communicatively connected to the audio processing device 1024; a second microphone 1028, configured to collect a residual sound signal and send the residual sound signal to the audio processing device 1024; the audio processing device 1024 is configured to, if it is determined that the received residual sound signal is greater than the sound signal threshold, adjust the signal processing parameter according to a preset manner to obtain a new signal processing parameter; and updating the currently stored signal processing parameters into new signal processing parameters.
The second microphone 1028 can be an analog microphone or a digital microphone other than the first microphone 1022. The first microphone 1022 and the second microphone 1028 may be of the same type or different types.
Optionally, for any noise control branch 102, a first distance between the sound source of the noise signal and the first microphone 1022 is smaller than a second distance between the sound source and the speaker 1026, and the second distance is smaller than a third distance between the sound source and the second microphone 1028.
The operation of the active noise reduction system including the second microphone 1028 may be described in detail with reference to fig. 2 and 3.
Fig. 2 is a schematic structural diagram of a second active noise reduction system provided in an embodiment of the present disclosure.
Referring to fig. 2, in the noise control branch 102, a first distance between the sound source of the noise signal and the first microphone 1022 is smaller than a second distance between the sound source of the voice signal and the speaker 1026, and the second distance is smaller than a third distance between the sound source of the voice signal and the second microphone 1028. Specifically, noise signals generated by sound sources located in offices and hallways are propagated to the first microphone 1022 through the propagation path 1. The first microphone 1022 transmits the collected noise signal to the audio processing device 1024. The audio processing device 1024 generates and sends an inverse sound signal to the speaker 1026. The inverted sound signal played by the speaker 1026 is canceled by the noise signal propagated through the propagation path 2 in the air while propagating to the second microphone 1028. The second microphone 1028 collects a residual sound signal after the cancellation of the inverted sound signal played by the speaker 1026 and the noise signal propagated through the propagation path 2 in the air, and sends the residual sound signal as an error feedback to the audio processing device 1024.
Due to the different positions of the first microphone 1022 and the second microphone 1028, noise signals emitted from the same sound source, for example, a noise signal traveling a short distance to the first microphone 1022 through the propagation path 1, and a noise signal traveling a long distance in air to the second microphone 1028 through the propagation path 2, will typically be attenuated by a portion as it travels to the second microphone 608. The objective that the embodiments of this specification want to achieve is to make the residual sound signal collected by the second microphone 1028 as small as possible, so that the opposite-phase sound signal played by the speaker 1026 is ideally the same as the attenuated noise signal collected by the second microphone 1028 in amplitude and opposite in phase, thereby achieving a good sound cancellation effect.
It should be noted that the first microphone 1022, the speaker 1026, and the second microphone 1028 belonging to the same noise control branch 102 may be arranged in a straight line, or may be arranged at a position convenient for installing equipment according to the environment of the specified noise reduction region.
Fig. 3 is a schematic structural diagram of a third active noise reduction system provided in the embodiment of the present disclosure.
Referring to fig. 3, the noise signal propagates to the first microphone 1022. The first microphone 1022 transmits the noise signal to the audio processing device 1024. The audio processing device 1024 has stored therein signal processing parameters. The audio processing device 1024 generates an inverse sound signal based on the noise signal and the stored signal processing parameters, and sends the inverse sound signal to the speaker 1026. The speaker 1026 plays the inverted sound signal. The inverted sound signal and the noise signal are mixed and then cancelled out, and the second microphone 1028 collects a residual sound signal obtained by the cancellation of the two signals and sends the residual sound signal to the audio processing device 1024, so as to adjust the signal processing parameters stored in the audio processing device 1024.
When the audio processing device 1024 determines that the received residual sound signal is greater than the preset sound signal threshold, it may be understood that the cancellation effect of the inverse sound signal and the noise signal is poor, which indicates that the signal processing parameter needs to be adjusted. The audio processing device 1024 updates the stored signal processing parameters in real-time according to the residual sound signal fed back by the second microphone 1028.
It should be noted that although there is a hysteresis in the algorithm for the audio processing device 1024 to adjust the signal processing parameters according to the received residual sound signal fed back by the second microphone 1028, the time consumed for updating the signal processing parameters once is very short, for example, the audio processing device 1024 can update the signal processing parameters once only by several tens of milliseconds. Whereas delays of tens of milliseconds are difficult to capture by the perception capabilities of the human ear. The sound collected within several tens of milliseconds can be generally regarded as a sound signal with a smooth waveform, so even if the signal processing parameters are obtained by the audio processing device 1024 according to feedback calculation of the sound signal before several tens of milliseconds, the signal processing parameters can still be used to generate an inverse sound signal capable of obtaining a good sound cancellation effect.
Optionally, the audio processing device is specifically configured to: and gradually adjusting the signal processing parameters according to the residual sound signal, the sound signal collected by the first microphone in the appointed time range and the reverse sound signal until the residual sound signal is not greater than the sound signal threshold value.
The audio processing device 1024 adjusts and processes the signal processing parameters according to a preset mode to obtain new signal processing parameters, including: the audio processing device 1024 adjusts the signal processing parameters successively according to the residual sound signal, the sound signal collected by the first microphone 1022 in the specified time range, and the inverse sound signal until the residual sound signal is not greater than the preset signal threshold.
The audio processing device 1024 stores therein signal processing parameters including filter weights hAF(t), the filter weights h are updated in the followingAF(t) is an example illustrating how to adjust the signal processing parameters:
updating the filter weight hAF(t) the following program language can be adopted, and the program language comprises a calculation formula to be circularly processed:
for(k＝-N,k≤L,k++){
hAF(t)＝b(t)-μe(t)x(t-k)}
and k is a loop variable in a loop statement of the program language, N and L are preset time parameters, and a specified time range can be determined according to N and L, so that the sound signal collected by the first microphone in the specified time range is determined. b (t) is the inverse sound signal generated by the audio processing device 1024, and μ is a preset coefficient, which can be preset or adjusted as needed. t is the time argument related to the sound signal to be processed, the inverted sound signal and the filter weights.
According to the residual sound signal, the sound signal collected by the first microphone in the appointed time range and the reversed-phase sound signal, the signal processing parameters are adjusted gradually until the residual sound signal is not larger than the sound signal threshold value, the longer the appointed time range determined by N and L is, the more data representing the received sound signal to be processed is, the more processable information is, the wider the frequency band range of processing can be expanded, and the processing capacity of the algorithm on high-frequency information is improved.
In an embodiment of the present application, the audio processing device 1024 may be in wireless communication with the first microphone 1022. The advantage of the first microphone 1022 transmitting the noise signal to the audio processing device 1024 over a wireless connection is described below in conjunction with fig. 4 and 5.
Fig. 4 is a timeline diagram of an active noise reduction system through wired transmission according to an embodiment of the present disclosure.
As shown in fig. 4, after the first microphone 1022 receives the noise signal at the time point 402, the noise signal is transmitted to the audio processing device 1024 by wired transmission. According to a theoretical value, the noise signal may arrive at the audio processing device 1024 at the point in time 404, the audio processing device 1024 generates an inverted sound signal, and the audio processing device 1024 may transmit the inverted sound signal to the speaker 1026 at the point in time 406.
However, in practical applications, when the noise signal is transmitted between the first microphone 1022 and the audio processing device 1024 through a wire, there is a time delay caused by ADC (analog to digital converter) conversion, and when the audio processing device 1024 processes the noise signal and sends the processed noise signal to the speaker 1026, there is a time delay caused by dac (digital to analog converter) conversion. The addition of the two time delays results in the loudspeaker being able to play the inverted sound signal virtually at the point in time 412. The noise signal travels through the air, arrives at the speaker at time 408, and arrives at the second microphone 1028 at time 410. The second microphone 1028 transmits the residual sound signal to the audio processing device 1024 at time point 414.
By using the active noise reduction system in wired transmission, for low-frequency noise, for example, noise signals below 1000Hz, due to the characteristic that the low-frequency signals are insensitive to phase delay, the degree of mismatch between the inverted sound signals processed by the audio processing device 1024 and the original noise signals is low, and noise reduction can be well counteracted. However, for high-frequency noise with short wavelength, for example, noise signals above 1000Hz, the phase mismatch is severe, thereby limiting the noise reduction performance in the high frequency band and lowering the upper frequency limit of active noise reduction.
In open office, conference, home and other scenes, the sound made by people is common noise. High-frequency noise exceeding 1000Hz often appears in human voice, so the noise reduction performance of the active noise reduction system through wired transmission is not good when facing the noise signal of human voice. Based on this, this application embodiment provides an active noise reduction system through wireless transmission.
Fig. 5 is a timeline diagram of an active noise reduction system through wireless transmission according to an embodiment of the present disclosure.
Referring to fig. 5, a noise signal is wirelessly transmitted between the first microphone 1022 and the audio processing device 1024. The wireless transmission substantially reduces the time required for signal transmission between the first microphone 1022 and the audio processing device 1024, resulting in a noise signal that originates from the first microphone 1022 at time 502, arrives at the audio processing device 1024 at time 504, generates an inverted sound signal, and arrives at the speaker at time 506. After a preset delay time, i.e. after the time period between time point 508 and time point 506 has elapsed, the loudspeaker plays the inverted sound signal at time point 508, and the noise signal propagates in the air, almost at the same time at time point 508, to the position where the loudspeaker 1026 is located. And the inverted sound signal and the noise signal propagating in the air arrive at the second microphone 1028 at approximately the same time at time point 510. The second microphone 1028 returns the residual sound signal to the audio processing device 1024 at time point 512.
As can be seen from fig. 4 and fig. 5, compared to the conventional wired connection method, in the present application, the wireless connection is adopted between the first microphone and the audio processing device, and the noise signal is transmitted based on the wireless connection, so that the time required for the noise signal to be transmitted between the first microphone 1022 and the audio processing device 1024 can be reduced, and the inverse sound signal is played after the preset delay time, so that the inverse sound signal played by the speaker 1026 and the noise signal propagated in the air can almost reach the second microphone 1028 at the same time and cancel each other, and thus when the noise signal is a high-frequency noise, a better technical effect of noise cancellation is obtained.
On the basis that the first microphone 1022 transmits the noise signal to the audio processing device 1024 through the wireless connection, the noise signal is transmitted to the audio processing device 1024 through the first microphone 1022 in a wireless manner faster than the noise signal travels from the air to the position where the audio processing device 1024 is located, so the audio processing device 1024 transmits the reversed-phase sound signal to the speaker 1026 after a preset delay time, so that the reversed-phase sound signal and the noise signal traveling in the air almost reach the position where the speaker 1026 is located at the same time, and further the reversed-phase sound signal and the noise signal traveling in the air almost reach the position where the second microphone 1028 is located at the same time. Therefore, the anti-phase sound signal and the noise signal which almost simultaneously reach the second microphone are mutually offset, and a better noise elimination effect can be achieved.
When the noise signal includes a high-frequency noise signal not less than a preset frequency, for example, a high-frequency noise signal greater than 1000Hz, the audio processing device 1024 sends an inverse sound signal to the speaker 1026 after a preset delay time, so that the time for the inverse sound signal played by the speaker 1026 to propagate to the second microphone is almost the same as the time for the noise signal to propagate to the second microphone in the air, and a better noise cancellation effect can be achieved compared with a technical scheme in which the inverse sound signal played by the speaker 1026 reaches the position of the second microphone first and the noise signal propagated in the air reaches the position of the second microphone 1028 later.
In particular, the preset delay time may be obtained by pre-testing the distance between the first microphone 1022 and the speaker 1026.
The active noise reduction system provided in the embodiments of the present disclosure may include one noise control branch 102, or may include a plurality of noise control branches 102. The more the number of the noise control branches 102 included in the active noise reduction system is, the denser the layout position of each noise control branch 102 is, the better the noise reduction effect is, but the more the number is, the resource waste may be caused, and the layout cost of the active noise reduction system is increased. Therefore, the number and the arrangement position of the noise control branches 102 included in the active noise reduction system can be determined according to the designated noise reduction region and the noise control range corresponding to each noise control branch 102, and the active noise reduction system has the characteristics of strong designability, high flexibility and the like.
The aforementioned designated noise reduction area may be an open or semi-open area where significant noise reduction requirements exist, such as an open conference room. In addition to the open or semi-open area, the designated noise reduction area may also be a closed area that itself has a poor sound insulation effect. For example, when activities such as taking a rest in a home environment are performed and the floor is low and close to the road, the home environment is easily affected by road noise, which causes a reduction in the quality of rest and a reduction in the quality of life. Although the area for rest in the home environment and the road are isolated from each other through the wall structure and do not belong to an open type or a semi-open type area, road noise may penetrate through the wall to interfere with normal work and life of personnel in the home environment, and the original wall structure may not meet the noise reduction requirement.
The following may describe, with reference to fig. 6 and fig. 7, determining the number and the layout positions of the noise control branches 102 included in the active noise reduction system according to the specified noise reduction region and the noise control range corresponding to each noise control branch 102.
Fig. 6 is a schematic diagram of an open office space provided in an embodiment of the present disclosure.
Referring to fig. 6, the designated noise reduction area may be a conference area, where the right side of the conference area is a wall, the upper and lower sides are aisles, and the left side is an office area. Then, according to the conference area of the designated noise reduction area, it can be determined that noise control branches are arranged on the upper side, the lower side and the left side of the conference area, so as to realize the noise reduction effect. The wall on the right side of the conference area has a certain sound insulation function, so that a noise control branch is not required to be arranged on the right side of the conference area.
Fig. 7 is a schematic diagram of a fourth structure of an active noise reduction system according to an embodiment of the present disclosure.
Referring to fig. 7, the designated noise reduction area is a semi-open area, and noise control branches 102 need to be arranged on both the upper side and the lower side and the left side of the core area of the designated noise reduction area. 5 noise control branches 102 are arranged for the core region, and are respectively arranged at the following five positions: the right lower part of the core area, the left side of the core area, the left upper part of the core area and the right upper part of the core area.
The noise control branch 102 shown in the figure includes a first microphone 1022, a speaker 1026, and a second microphone 1028. The other noise control branches are similar to the devices included in the noise control branch 102 and will not be described herein.
When one side of the designated noise reduction region does not have a wall structure, the side is open to the outside of the designated noise reduction region, and noise outside the designated noise reduction region is easily transmitted to the designated noise reduction region through the side, so in order to avoid noise from being transmitted into the designated noise reduction region, one or more noise control branches should be arranged on the side.
And determining the number and the arrangement positions of the noise control branches included in the active noise reduction system according to the noise control range corresponding to each noise control branch on the side without the wall structure in the specified noise reduction area, for example, if the noise control range corresponding to one noise control branch is two meters, arranging one noise control branch every two meters on the same side of the core area.
Optionally, the noise control branch 102 includes: the microphone array comprises an audio processing device 1024, a first microphone array wirelessly connected with the audio processing device 1024, and a loudspeaker array and a second microphone array respectively connected with the audio processing device 1024 in a communication mode.
A microphone array refers to a system composed of a certain number of microphones for processing the spatial characteristics of a sound field. A speaker array refers to a system consisting of a certain number of speakers for playing voice signals.
The first microphone 1022 in various embodiments of the present description may be replaced with a first microphone array, the speaker 1026 may be replaced with a speaker array, and the second microphone 1028 may be replaced with a second microphone array. During specific implementation, a microphone array and a loudspeaker array are adopted to achieve a better active noise reduction effect. The first loudspeaker and the second loudspeaker play different roles in the system, and can be the same type of loudspeaker or different types of loudspeakers from the viewpoint of equipment; the first microphone 1022 and the second microphone 1028 play different roles in the present system, and may be the same type of microphone or different types of microphones from the viewpoint of the device; the first microphone array and the second microphone array are the same, and the description is omitted here.
Optionally, the first microphone 1022 and the second microphone 1028 comprise different microphones of a webcam IPC device; the speaker includes a speaker of an IPC device.
IPC (IP Camera) is a new generation Camera generated by combining a conventional Camera and a network technology. As a new monitoring camera, the system completely gets rid of the constraint of simulation monitoring and has the advantages of good expansibility, strong centralized management capability, low construction cost and the like. Through the distributed layout of a plurality of IPC devices, a certain 'quiet' area can be formed, and the area has the characteristics of privacy protection and low noise and can meet the requirements of offices, families and the like. IPC devices may include microphones, speakers, audio processing devices.
The first microphone 1022 may be a microphone of the IPC device, a first microphone array, or may be formed by a plurality of microphones included in at least one set of IPC devices. The second microphone 1028 is similar to the first microphone 1022 and will not be described herein. The speaker 1026 may be a speaker of the IPC device, and the speaker array may be formed by a plurality of sets of speakers included in the IPC device.
The first microphone 1022 and the second microphone 1028 comprise different microphones of a webcam IPC device, e.g., the IPC device comprises microphone 1 and microphone 2, the first microphone 1022 may comprise microphone 1, and the second microphone 1028 may comprise microphone 2.
In the embodiment of the present specification, an active noise reduction system may also be configured by combining an independent microphone, an independent speaker, an independent audio processing device, a microphone of the IPC device, a speaker of the IPC device, and the like.
Optionally, the sound emission source of the noise signal is located outside the boundary region of the specified noise reduction region; the first microphone 1022 is disposed in the boundary region; a speaker 1026 is provided in the boundary region; the second microphone 1028 is disposed in a core region of the designated noise reduction region; the border area surrounds the core area.
Fig. 8 is a schematic diagram of an open conference room provided in an embodiment of the present disclosure. Referring to fig. 8, a core region 802 of a designated noise reduction region is surrounded by a boundary region 804 of the designated noise reduction region.
In particular implementations, the first microphone 1022 may be disposed in a boundary region of the designated noise reduction region, the speaker 1026 may be disposed in a boundary region of the designated noise reduction region, and the second microphone 1028 may be disposed in a core region of the designated noise reduction region.
In particular implementations, for example, the designated noise reduction area includes a conference room; the first microphone is suspended on a ceiling of a boundary area of the conference room opposite to the core area; the loudspeaker is hung on the ceiling of the boundary area facing the second microphone; the second microphone is suspended from a ceiling of a core area of the conference room facing the speaker.
When the noise reduction area is designated as a conference room, the first microphone 1022 may be disposed in a boundary area of the conference room, has a small size and occupies no space, and may be suspended on a ceiling of the boundary area to receive a noise signal; a speaker 1026, which can be installed in the border area of the conference room, and can be fixed by hanging on the ceiling, for playing the inverse sound signal; a second microphone 1028 may be positioned in the core area near the boundary, suspended from the ceiling of the core area, for receiving the residual sound signal for feedback to the audio processing device 1024.
In an embodiment of the present specification, the active noise reduction system includes at least one noise control branch, where the noise control branch includes: the system comprises an audio processing device, a first microphone wirelessly connected with the audio processing device and a loudspeaker in communication connection with the audio processing device; the first microphone is used for acquiring a noise signal and transmitting the noise signal to the audio processing equipment through wireless connection; the audio processing equipment is used for generating an inverse sound signal according to the noise signal and the currently stored signal processing parameter and sending the inverse sound signal to the loudspeaker after the preset delay time; the residual sound signal after the phase-reversed sound signal and the noise signal are mutually offset is not greater than a preset sound signal threshold value; and the loudspeaker is used for playing the inverse sound signal. Therefore, the noise signal is transmitted between the first microphone and the audio processing device through wireless connection, transmission delay of the noise signal between the first microphone and the audio processing device can be reduced based on the characteristic of wireless transmission, the problems of signal phase mismatch and the like caused by large transmission delay are avoided, and the processing rate of the noise signal is improved. The reverse sound signal played by the loudspeaker can be mutually offset with the noise signal propagated in the air by sending the reverse sound signal after the preset delay time; for an open or semi-open area, noise signals can be prevented from being transmitted to the area and causing adverse effects on personnel in the area, and therefore noise reduction of the open or semi-open area is achieved.
Based on the same technical concept, the embodiment of the present specification further provides an active noise reduction method, which can be applied to the active noise reduction system provided in the foregoing embodiment.
Fig. 9 is a schematic flowchart of an active noise reduction method provided in an embodiment of the present disclosure, and as shown in fig. 9, the method includes: .
And S902, acquiring the noise signal collected by the first microphone through wireless connection.
The noise signal may be a noise signal generated outside a designated noise reduction area where noise reduction requirements exist, for example, speech sounds of people passing through a passageway outside an open conference room. The noise signal may be a voice of a person speaking, a voice of moving an object, or a voice of audio software played by the electronic device, and the description does not specially limit the type of the noise signal.
In the active noise reduction method in the embodiment of the present specification, a first microphone included in the active noise reduction system is in wireless communication connection with the audio processing device, so that a time for the first microphone to collect and transmit a noise signal to the audio processing device is less than a time for the noise signal to propagate in the air to the audio processing device, that is, the wirelessly transmitted noise signal reaches the audio processing device first, and the noise signal propagating in the air reaches a position where the audio processing device is located later.
And S904, generating an inverse sound signal according to the noise signal and the currently stored signal processing parameter.
The audio processing apparatus has stored therein a signal processing parameter for processing the noise signal to obtain an intermediate sound signal that can be expressed by an approximate mathematical expression, and performing an inversion process on the intermediate sound signal to obtain an inverted sound signal.
Optionally, the signal processing parameters include filter weights; generating an inverted sound signal based on the noise signal and the currently stored signal processing parameters, comprising: generating an intermediate sound signal according to the noise signal and the filter weight; the intermediate audio signal is processed in reverse to generate a reverse audio signal.
The noise signal may include the voice of a human speaking. In general, there is instability in the voice of a person speaking, and the voice greatly fluctuates depending on the content, emotion, and the like. Therefore, no matter the first microphone collects only one person speaking voice, or collects the voice mixed by the voices of a plurality of persons speaking, or collects the voice mixed by the voices of the persons speaking and other voices, the collected voice signal to be processed has instability, the voice signal is difficult to express through a fixed mathematical formula, and further the voice signal to be processed is difficult to directly carry out reverse phase processing.
In the embodiment of the present specification, the audio processing device stores signal processing parameters, and the signal processing parameters include filter weights hAF(t) of (d). Filter weight hAF(t) processing the sound signal to be processed to obtain an intermediate sound signal, the intermediate sound signal being representable by an approximate mathematical expression, the audio processing device performing an inverse phase processing on the intermediate sound signal to obtain an inverse sound signal, the mathematical expression of the sound signal being achieved.
S906, sending the reversed-phase sound signal to a loudspeaker after the preset delay time so that the loudspeaker plays the reversed-phase sound signal; and the residual sound signal after the phase-reversed sound signal and the noise signal are mutually offset is not greater than a preset sound signal threshold value.
In a specific implementation, the audio processing device may send the generated inverse sound signal to the speaker after a preset delay time, so that the speaker plays the inverse sound signal.
And the residual sound signal after the phase-reversed sound signal and the noise signal are mutually offset is not greater than a preset sound signal threshold value. Considering theoretical values, the active noise reduction system expects to completely cancel the inverse sound signal and the noise signal, i.e., the residual sound signal takes a value of 0. However, in the actual operation process, complete cancellation is almost impossible, and when the value of the residual sound signal is not larger than the preset sound signal threshold value, the human ear can hardly perceive the residual sound signal, and a good sound cancellation effect can be achieved at the moment, so that sound insulation of an open type or a semi-open type area is realized.
Optionally, the active noise reduction method further includes: acquiring a residual sound signal collected by a second microphone; if the residual sound signal is determined to be larger than the sound signal threshold, adjusting the signal processing parameters according to a preset mode to obtain new signal processing parameters; and updating the currently stored signal processing parameters into new signal processing parameters.
When the noise signal includes a high-frequency noise signal not less than a preset frequency, for example, a high-frequency noise signal greater than 1000Hz, the audio processing apparatus sends the inverse sound signal to the speaker after a preset delay time, so that the time for the inverse sound signal played by the speaker to propagate to the second microphone is almost the same as the time for the noise signal to propagate in the air to the second microphone.
Therefore, the audio processing apparatus sends the inverse sound signal to the speaker 1026 after the preset delay time, so that the inverse sound signal and the noise signal propagating in the air can reach the position where the second microphone 1028 is located at almost the same time, and a better noise cancellation effect can be achieved for the high-frequency noise signal.
If it is determined that the received residual sound signal is greater than the sound signal threshold, it can be understood that the cancellation effect of the inverse sound signal and the voice signal is poor, and at this time, it indicates that the filter weight needs to be adjusted. The filter weights stored in the audio processing device are updated in real time according to the residual sound signal fed back by the second microphone.
It should be noted that although there is hysteresis in terms of algorithm, the audio processing device adjusts the filter weights according to the received residual sound signal fed back by the second microphone, the calculation speed of updating the filter weights is very fast, for example, the updated filter weights can be calculated only by tens of milliseconds, and the collected new noise signal is processed according to the updated filter weights. Whereas delays of tens of milliseconds are difficult to capture by the perception capabilities of the human ear. The sound collected within tens of milliseconds can be generally regarded as a smooth sound signal with small difference, so even if the filter weight is calculated according to the feedback of the sound signal before tens of milliseconds, the filter weight can still be used for generating an anti-phase sound signal with good sound cancellation effect.
In practical application, in the second microphone, short-time sound can be heard from no sound to initial sound emission, and in the process that the active noise reduction system continuously feeds back according to the residual sound signal, the system can quickly adjust the weight value of the filter, so that the residual sound signal is reduced to a preset sound signal threshold value, and therefore a better sound cancellation effect can be achieved, and sound insulation treatment of an open type or a semi-open type area is achieved.
Optionally, adjusting the signal processing parameter according to a preset mode to obtain a new signal processing parameter, including: and gradually adjusting the signal processing parameters according to the residual sound signal, the sound signal collected by the first microphone in the appointed time range and the reverse sound signal until the residual sound signal is not greater than a preset signal threshold value.
According to the residual sound signal, the sound signal collected by the first microphone in the appointed time range and the reversed-phase sound signal, the signal processing parameters are adjusted gradually until the residual sound signal is not larger than the sound signal threshold value, the longer the appointed time range is, the more information can be processed, the processing frequency band range can be expanded, and the processing capacity of the algorithm on high-frequency information is improved.
The active noise reduction method provided by the embodiment of the specification acquires a noise signal acquired by a first microphone; generating an inverse sound signal according to the noise signal and the currently stored signal processing parameters; sending the reversed phase sound signal to a loudspeaker so that the loudspeaker plays the reversed phase sound signal; and the residual sound signal after the phase-reversed sound signal and the noise signal are mutually offset is not greater than a preset sound signal threshold value. Therefore, the noise signal is transmitted between the first microphone and the audio processing device through wireless connection, transmission delay of the noise signal between the first microphone and the audio processing device can be reduced based on the characteristic of wireless transmission, the problems of signal phase mismatch and the like caused by large transmission delay are avoided, and the processing rate of the noise signal is improved. The reverse sound signal played by the loudspeaker can be mutually offset with the noise signal propagated in the air by sending the reverse sound signal after the preset delay time; for an open or semi-open area, noise signals can be prevented from being transmitted to the area and causing adverse effects on personnel in the area, and therefore noise reduction of the open or semi-open area is achieved.
For the above method embodiment, since it is basically similar to the system embodiment, the description is simple, and the relevant points can be referred to the partial description of the system embodiment.
Based on the same technical concept, an embodiment of the present specification further provides an active noise reduction device, which is applied to an active noise reduction system, where the active noise reduction system includes at least one noise control branch, and the noise control branch includes a first microphone and a speaker; fig. 10 is a schematic diagram illustrating a module composition of an active noise reduction apparatus provided in an embodiment of the present disclosure, and as shown in fig. 10, the apparatus includes:
a memory 1002 for storing signal processing parameters;
a processor 1004 for acquiring the noise signal collected by the first microphone through a wireless connection; generating an inverse sound signal according to the noise signal and the currently stored signal processing parameters; sending the reversed-phase sound signal to a loudspeaker after a preset delay time so that the loudspeaker plays the reversed-phase sound signal; and the residual sound signal after the phase-reversed sound signal and the noise signal are mutually offset is not greater than a preset sound signal threshold value.
Optionally, the processor 1004 is further configured to:
acquiring a residual sound signal collected by a second microphone;
if the residual sound signal is determined to be larger than the sound signal threshold, adjusting the signal processing parameters according to a preset mode to obtain new signal processing parameters; and updating the currently stored signal processing parameters into new signal processing parameters.
Optionally, the processor 1004 is specifically configured to:
and gradually adjusting the signal processing parameters according to the residual sound signal, the noise signal collected by the first microphone in the appointed time range and the reverse sound signal until the residual sound signal is not greater than a preset signal threshold value.
Optionally, the signal processing parameters include filter weights; the processor 1004 is specifically configured to:
generating an inverted sound signal based on the noise signal and the currently stored signal processing parameters, comprising:
generating an intermediate sound signal according to the noise signal and the filter weight;
the intermediate audio signal is processed in reverse to generate a reverse audio signal.
The active noise reduction device provided by the embodiment of the specification acquires a noise signal acquired by a first microphone through wireless connection; generating an inverse sound signal according to the noise signal and the currently stored signal processing parameters; sending the reversed-phase sound signal to a loudspeaker after a preset delay time so that the loudspeaker plays the reversed-phase sound signal; and the residual sound signal after the phase-reversed sound signal and the noise signal are mutually offset is not greater than a preset sound signal threshold value. Therefore, the first microphone and the audio processing device are connected in a wireless mode, the time required by signal transmission between the first microphone and the audio processing device is shortened obviously, the reverse sound signal played by the loudspeaker in a delayed mode and the noise signal are offset by sending the reverse sound signal after the preset delay time, and the noise reduction effect in an open type or semi-open type area can be improved.
In addition, for the embodiment of the active noise reduction device, since it is basically similar to the method embodiment, the description is relatively simple, and for relevant points, reference may be made to part of the description of the method embodiment. Further, it should be noted that, among the respective components of the active noise reduction apparatus of the present invention, the components thereof are logically divided according to the functions to be implemented, but the present invention is not limited thereto, and the respective components may be newly divided or combined as necessary.
Fig. 11 is a schematic structural diagram of an electronic device according to an embodiment of the present disclosure, and referring to fig. 11, the electronic device includes a processor, an internal bus, a network interface, a memory, and a non-volatile memory, and may also include hardware required by other services. The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs, forming the audio processing device on a logical level. Of course, besides the software implementation, the present application does not exclude other implementations, such as logic devices or a combination of software and hardware, and the like, that is, the execution subject of the following processing flow is not limited to each logic unit, and may also be hardware or logic devices.
The network interface, the processor and the memory may be interconnected by a bus system. The bus may be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, an EISA (Extended Industry Standard Architecture) bus, or the like. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one double-headed arrow is shown in FIG. 11, but that does not indicate only one bus or one type of bus.
The memory is used for storing programs. In particular, the program may include program code including computer operating instructions. The memory may include both read-only memory and random access memory, and provides instructions and data to the processor. The Memory may include a Random-Access Memory (RAM) and may also include a non-volatile Memory (non-volatile Memory), such as at least 1 disk Memory.
The processor is used for executing the program stored in the memory and specifically executing the following steps:
acquiring a noise signal acquired by a first microphone through wireless connection;
generating an inverse sound signal according to the noise signal and the currently stored signal processing parameters;
sending the reversed-phase sound signal to a loudspeaker after a preset delay time so that the loudspeaker plays the reversed-phase sound signal; and the residual sound signal after the phase-reversed sound signal and the noise signal are mutually offset is not greater than a preset sound signal threshold value.
The method performed by the active noise reduction device according to the embodiment shown in fig. 10 of the present application may be applied to or implemented by a processor. The processor may be an integrated circuit chip having signal processing capabilities. In implementation, the steps of the above method may be performed by integrated logic circuits of hardware in a processor or instructions in the form of software. The Processor may be a general-purpose Processor, including a Central Processing Unit (CPU), a Network Processor (NP), and the like; it may also be an audio processing device 1024 (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic device, discrete hardware component. The various methods, steps, and logic blocks disclosed in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in a memory, and a processor reads information in the memory and completes the steps of the method in combination with hardware of the processor.
Based on the same technical concept, embodiments of the present application also provide a computer-readable storage medium storing one or more programs, which when executed by an electronic device including a plurality of application programs, cause the electronic device to perform the active noise reduction method provided by the foregoing method embodiments.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.
The foregoing description has been directed to specific embodiments of this disclosure. Other embodiments are within the scope of the following claims. In some cases, the actions or steps recited in the claims may be performed in a different order than in the embodiments and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing may also be possible or may be advantageous.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
In a typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.
The memory may include forms of volatile memory in a computer readable medium, Random Access Memory (RAM) and/or non-volatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). Memory is an example of a computer-readable medium.
Computer-readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), Digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device. As defined herein, a computer readable medium does not include a transitory computer readable medium such as a modulated data signal and a carrier wave.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The above description is only an example of the present application and is not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims (15)

1. An active noise reduction system comprising at least one noise control branch, the noise control branch comprising: the system comprises an audio processing device, a first microphone wirelessly connected with the audio processing device and a loudspeaker in communication connection with the audio processing device;
the first microphone is used for collecting noise signals and sending the noise signals to the audio processing equipment through the wireless connection;
the audio processing device is used for generating an inverse sound signal according to the noise signal and the currently stored signal processing parameter, and sending the inverse sound signal to the loudspeaker after a preset delay time; the residual sound signal after the phase-reversed sound signal and the noise signal are mutually offset is not greater than a preset sound signal threshold value;
the loudspeaker is used for playing the reversed phase sound signal.
2. The system of claim 1, wherein the noise control branch further comprises: a second microphone in communicative connection with the audio processing device;
the second microphone is used for collecting the residual sound signal and sending the residual sound signal to the audio processing equipment;
the audio processing device is configured to, if it is determined that the received residual sound signal is greater than the sound signal threshold, adjust the signal processing parameter according to a preset manner to obtain a new signal processing parameter; and updating the currently stored signal processing parameters into the new signal processing parameters.
3. The system of claim 2, wherein the audio processing device is specifically configured to:
and gradually adjusting the signal processing parameters according to the residual sound signal, the noise signal collected by the first microphone in a specified time range and the reverse sound signal until the residual sound signal is not greater than a preset signal threshold.
4. The system of claim 1, wherein the signal processing parameters include filter weights; the digital signal processing module is specifically configured to:
generating an intermediate sound signal according to the noise signal and the filter weight;
and carrying out reverse processing on the intermediate sound signal to generate a reverse sound signal.
5. The system of claim 2,
the sound emission source of the noise signal is positioned outside the boundary area of the designated noise reduction area;
the first microphone is arranged in the boundary area;
the loudspeaker is arranged in the boundary area;
the second microphone is arranged in a core area of the designated noise reduction area; the border area surrounds the core area.
6. The system of claim 1,
aiming at any one noise control branch circuit, a first distance between a sound generating source of the noise signal and the first microphone is smaller than a second distance between the sound generating source and the loudspeaker, and the second distance is smaller than a third distance between the sound generating source and the second microphone.
7. The system of claim 2, wherein the noise control branch comprises: the microphone array comprises an audio processing device, a first microphone array wirelessly connected with the audio processing device, and a loudspeaker array and a second microphone array which are respectively in communication connection with the audio processing device.
8. The system of claim 2, wherein the first microphone and the second microphone comprise different microphones of a webcam IPC device; the speaker includes a speaker of the IPC device.
9. An active noise reduction method is applied to an active noise reduction system, wherein the active noise reduction system comprises at least one noise control branch, and the noise control branch comprises an audio processing device, a first microphone wirelessly connected with the audio processing device, and a loudspeaker communicatively connected with the audio processing device; the method comprises the following steps:
acquiring a noise signal acquired by the first microphone through the wireless connection;
generating an inverse sound signal according to the noise signal and the currently stored signal processing parameters;
sending the reversed-phase sound signal to the loudspeaker after a preset delay time so that the loudspeaker plays the reversed-phase sound signal; and the residual sound signal after the phase-reversed sound signal and the noise signal are mutually offset is not greater than a preset sound signal threshold value.
10. The method of claim 9, wherein the noise control branch further comprises a second microphone; the method further comprises the following steps:
acquiring the residual sound signal collected by the second microphone;
if the residual sound signal is determined to be larger than the sound signal threshold, adjusting the signal processing parameter according to a preset mode to obtain a new signal processing parameter; and updating the currently stored signal processing parameters into the new signal processing parameters.
11. The method of claim 10, wherein adjusting the signal processing parameters according to a preset manner to obtain new signal processing parameters comprises:
and gradually adjusting the signal processing parameters according to the residual sound signal, the noise signal collected by the first microphone in a specified time range and the reverse sound signal until the residual sound signal is not greater than a preset signal threshold.
12. The method of claim 9, wherein the signal processing parameters include filter weights; generating an inverse sound signal based on the noise signal and the currently stored signal processing parameters, comprising:
generating an intermediate sound signal according to the noise signal and the filter weight;
and carrying out reverse processing on the intermediate sound signal to generate the reverse sound signal.
13. An active noise reduction device is applied to an active noise reduction system, wherein the active noise reduction system comprises at least one noise control branch, and the noise control branch comprises a first microphone and a loudspeaker; the device comprises:
a memory for storing signal processing parameters;
the processor is used for acquiring the noise signal acquired by the first microphone through wireless connection; generating an inverse sound signal according to the noise signal and the currently stored signal processing parameters; sending the reversed-phase sound signal to the loudspeaker after a preset delay time so that the loudspeaker plays the reversed-phase sound signal; and the residual sound signal after the phase-reversed sound signal and the noise signal are mutually offset is not greater than a preset sound signal threshold value.
14. An electronic device, comprising: a processor, a communication interface, a memory, and a communication bus; the processor, the communication interface and the memory complete mutual communication through a bus; a memory for storing a computer program; a processor for executing a program stored in a memory to implement the steps of the active noise reduction method according to any of the preceding claims 9 to 12.
15. A computer-readable storage medium, characterized in that the computer-readable storage medium has stored thereon a computer program which, when being executed by a processor, carries out the steps of the active noise reduction method according to any of the preceding claims 9 to 12.
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