Targeted enhancement local amplification methods, systems, devices, and storage media

Abstract

This application relates to a method, system, device, and storage medium for directional enhancement of local loudspeaker amplification, belonging to the field of signal processing technology. It includes acquiring N+1 microphone signals, where N is greater than or equal to 4; estimating the time delay of the N+1 microphone signals to obtain the time-delayed signals of the N+1 channels and determining the location of the target sound source; acquiring a directional enhancement filter based on the time-delayed signals; and applying the directional enhancement filter to the time-delayed signals to obtain an enhanced signal. This application has the following effects: directional pickup and enhancement of the speaker's voice, and superimposing a perturbation signal on the enhanced signal, disrupting the correlation between sound pickup and playback, further suppressing feedback problems at their source, improving the system's anti-feedback and interference capabilities, and improving signal sound quality.

Description

Technical Field

[0001] This application relates to the field of signal processing technology, and in particular to a method, system, device, and storage medium for directional enhancement of local loudspeaker amplification. Background Art

[0002] Local amplification is a common acoustic application, such as in classrooms and large conference rooms. By using distributed speakers, the speaker's voice can be amplified, ensuring that everyone in the room can hear the speaker clearly.

[0003] The main problems with existing local public address systems include:

[0004] The sound is prone to feedback. Because it's a local amplification system, the microphones in the system pick up the voices of the speaker and listeners, amplify them, and play them back. Simultaneously, this sound is also picked up again by the microphones, forming a closed loop. When the signal gain reaches a certain level, the equipment will produce feedback, potentially damaging it.

[0005] Poor sound quality from amplification. To suppress feedback, different manufacturers employ different feedback-reducing strategies, such as gain attenuation and notch filters. While these methods can suppress feedback, they also destroy some sound components, causing sound distortion and affecting sound quality.

[0006] It has weak interference suppression capabilities. For open microphones, it picks up not only the speaker's voice but also the listener's voice. Summary of the Invention

[0007] To address the issues of sound distortion and reduced sound quality in local amplification systems, this application provides a method, system, device, and storage medium for directional enhancement of local amplification.

[0008] A method for directional enhancement of local loudspeaker amplification, comprising:

[0009] Acquire N+1 microphone signals, where N is greater than or equal to 4;

[0010] The time delay of the N+1 microphone signals is estimated to obtain the time delay signals of the N+1 channels and determine the location of the target sound source;

[0011] Based on the time-delay signal, a directional enhancement filter is obtained;

[0012] The directional enhancement filter is applied to the time-delay signal to obtain an enhanced signal.

[0013] By adopting the above technical solution, the microphone signal is delayed based on the cross-correlation algorithm. The location of the target sound source can be determined based on the obtained delay time and the correlation of the sound signal, and the sound signal is aligned. Then, a directional enhancement filter is calculated on the delay signal and applied to the delay signal to enhance the target sound and reduce noise. This achieves directional pickup and enhancement of only the speaker's voice, improves the system's anti-feedback and interference capabilities, and improves the problem of poor signal quality.

[0014] Preferably, after obtaining the enhanced signal, the method further includes:

[0015] A perturbation signal is superimposed on the enhanced signal to obtain the playback signal.

[0016] By adopting the above technical solution, a perturbation signal is superimposed on the enhanced signal. The perturbation signal disrupts the correlation between the pickup and playback signals, thereby further suppressing the occurrence of howling from the root and improving the signal quality.

[0017] Preferably, obtaining the directional enhancement filter based on the time-delay signal includes:

[0018] Obtain the cross-correlation power spectral density between the time-delayed signals, average the cross-correlation power spectral density to obtain the cross-correlation average signal, and obtain the real part of the cross-correlation average signal;

[0019] Obtain the autocorrelation power spectral density of the time-delay signal, and average the autocorrelation power spectral density to obtain the autocorrelation average signal;

[0020] The ratio of the real part of the cross-correlation average signal to the autocorrelation average signal at each frequency point is used as the directional enhancement filter.

[0021] By adopting the above technical solution, a directional enhancement filter is obtained based on the ratio of the real part of the cross-correlation average signal to the autocorrelation average signal. The directional enhancement filter is used to directionally enhance the speaker's voice.

[0022] Preferably, the superimposed disturbance signal includes:

[0023] The short-time Fourier spectrum of the enhanced signal is filtered to obtain the perturbation signal.

[0024] By adopting the above technical solution, the short-time Fourier spectrum of the enhanced signal is filtered to obtain a disturbance signal. The disturbance signal filters the amplified sound and noise, destroys the correlation between sound pickup and playback, and thus improves the system's anti-feedback capability.

[0025] Preferably, filtering the short-time Fourier spectrum of the enhanced signal includes:

[0026] The short-time Fourier spectrum of the enhanced signal is multiplied by a complex exponential phase correction term, which includes a time-invariant component and a periodic time-varying component.

[0027] By adopting the above technical solution, the short-time Fourier spectrum of the enhanced signal is multiplied by a complex exponential phase correction term, which enables filtering of the short-time Fourier spectrum of the enhanced signal.

[0028] Preferably, applying the directional enhancement filter to the time-delay signal to obtain the enhanced signal includes:

[0029] The directional enhancement filter directionally enhances the speaker's voice on the time-delay signal and weakens the interference signal. The enhancement range of the speaker's voice is 3dB-6dB, and the weakening range of the interference signal is 10dB-13dB; thus obtaining a directional pickup and enhancement signal of the speaker's voice.

[0030] By adopting the above technical solution, the directional enhancement filter can enhance the speaker's voice signal by 3dB-6dB and reduce interference signals by 10dB-13dB.

[0031] A directional enhancement local loudspeaker system includes:

[0032] The signal acquisition module is used to acquire N+1 microphone signals, where N is greater than or equal to 4;

[0033] The time delay estimation module is used to estimate the time delay of the N+1 microphone signals, obtain the time delay signals of the N+1 channels, and determine the location of the target sound source.

[0034] The calculation module is used to obtain a directional enhancement filter based on the time-delay signal;

[0035] The application module is used to apply the directional enhancement filter to the time-delay signal to obtain an enhanced signal.

[0036] By adopting the above technical solution, the signal acquisition module acquires N+1 microphone signals, the time delay estimation module performs time delay estimation on the acquired N+1 microphone signals according to the cross-correlation algorithm, performs signal alignment, and determines the location of the target sound source based on the time delay and signal correlation, the calculation module calculates the directional enhancement filter on the time delay signal, and the application module applies the directional enhancement filter to the time delay signal to directionally enhance the speaker's voice and reduce noise, thereby outputting the enhanced speaker's voice.

[0037] Preferably, the N+1 microphone signals correspond to N+1 microphones, wherein the N+1 microphones include one center microphone and N surround microphones, wherein: the N surround microphones are equally spaced and arranged in a ring on the plane, the center microphone is located at the central axis of the ring plane formed by the N surround microphones, and the center microphone is located at the central axis.

[0038] By adopting the above technical solution, the microphone can pick up sound more comprehensively, better locate the sound source, and produce better sound reproduction.

[0039] An apparatus includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the aforementioned directional enhancement local amplification method.

[0040] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the aforementioned directional enhancement local amplification method.

[0041] In summary, this application includes at least one of the following beneficial effects:

[0042] 1. By delaying the acquired N+1 microphone signals, the audio signals are aligned and the location of the target sound source is obtained. The cross-correlation spectrum of each delayed signal is calculated, and a directional enhancement filter is calculated. The directional enhancement filter is applied to each delayed signal to amplify only the speaker's voice and suppress the voices of the listeners and the amplified voice. This achieves directional enhancement of only the speaker's voice, enabling everyone in the room to hear the speaker's voice clearly and improving the sound quality of the playback signal.

[0043] 2. A perturbation signal is superimposed on the enhanced signal, which further disrupts the correlation between the pickup and playback signals, suppressing feedback at its source, improving the poor sound quality of the playback signal, and enhancing the system's anti-feedback and anti-interference capabilities. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the directional enhancement process of a directional enhancement local amplification method, system, device, and storage medium according to an embodiment of this application.

[0045] Figure 2 This is a diagram illustrating the directional enhancement effect of a directional enhancement local amplification method, system, device, and storage medium according to an embodiment of this application.

[0046] Figure 3 This is a comparison diagram of the disturbance signal before and after superposition in a directional enhancement local amplification method, system, device, and storage medium according to an embodiment of this application;

[0047] Figure 4 This is a block diagram of a directional enhancement local amplification method, system, device, and storage medium according to an embodiment of this application;

[0048] Figure 5 This is a schematic diagram of the microphone placement in a directional enhancement local amplification method, system, device, and storage medium according to an embodiment of this application;

[0049] Figure 6 This is an internal structural block diagram of a device for a directional enhancement local amplification method, system, device, and storage medium according to an embodiment of this application. Detailed Implementation

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0051] For local amplification systems, the listener's voice does not need to be amplified by the amplification system; it needs to be suppressed.

[0052] This application provides a method for directional enhancement of local loudspeaker amplification, referring to... Figure 1 ,include

[0053] S10. Obtain N+1 microphone signals, where N is greater than or equal to 4.

[0054] S20. Estimate the time delay of the N+1 microphone signals to obtain the time delay signals of the N+1 channels and determine the location of the target sound source.

[0055] S30. Obtain a directional enhancement filter based on the time-delay signal.

[0056] S40. Apply a directional enhancement filter to the time-delay signal to obtain an enhanced signal.

[0057] The microphone signals include the speaker's voice, the listener's voice, and amplified sound. N microphones are located in different directions on the same plane, with one microphone positioned on the central axis of the plane formed by the N microphones. A cross-correlation estimation method is used to determine the location of the target sound source based on the time delay of the N+1 microphone signals and to align the acquired microphone signals. Setting N to be greater than or equal to 4 is to acquire more signals for better sound source localization.

[0058] Its function is that, due to their different positions, the N+1 microphones picking up target sound sources at the same location have different time delays. The different time delays in the N+1 microphone signals are calculated based on cross-correlation, and then the location of the target sound source is determined and the signals are aligned based on these time delays. The directional enhancement filter directionally enhances the speaker's voice on the N+1 time-delayed signals and attenuates interference signals. The speaker's signal enhancement range is 3dB-6dB, for example, 5dB, while the interference signal attenuation range is 10dB-13dB, for example, 12dB. This achieves directional pickup and enhancement of only the speaker's voice, improving the system's anti-feedback and interference capabilities, and addressing the problem of poor sound quality. (Refer to...) Figure 2 This is a diagram showing the effect of targeted enhancement.

[0059] Specifically, the delay estimation method in this application employs a cross-correlation algorithm, as follows:

[0060] The cross-correlation function of a discrete signal is defined as:

[0061]

[0062] From the above equation, we can see that the cross-correlation is a function of the relative delay τ, x k and y k+x Given N+1 input microphone signals, it is clear that the delay value that maximizes the cross-correlation coefficient can be taken as the estimate of the arrival time difference, i.e.:

[0063]

[0064] However, this algorithm is easily affected by noise and reverberation in practice, and its performance is not very stable. Therefore, the concept of generalized cross-correlation is introduced. The arrival time difference is obtained by maximizing the delay value of the generalized cross-correlation function.

[0065]

[0066] in, Defined as the inverse Fourier transform of the generalized cross spectrum:

[0067]

[0068] γ f It is a weighting equation in the frequency domain. Cross spectrum is represented by the following definition:

[0069] Here, γ f Defined as This is equivalent to normalizing the amplitude, leaving only the phase information.

[0070] Based on the time-delay signal, a directional enhancement filter is obtained, including:

[0071] Obtain the cross-correlation power spectral density between time-delayed signals, average the cross-correlation power spectral density to obtain the average cross-correlation signal, and obtain the real part of the average cross-correlation signal.

[0072] Obtain the autocorrelation power spectral density of the time-delayed signal, and average the autocorrelation power spectral density to obtain the average autocorrelation signal; use the ratio of the real part of the cross-correlation average signal to the average autocorrelation signal at each frequency point as the directional enhancement filter.

[0073] Specifically, this involves: acquiring the time-delay signal v l Then for signal v l Perform an FFT transform, compensate for each frequency point in the frequency domain, and then sum the results to obtain the delayed-aligned signal.

[0074] Calculate the cross-correlation power spectrum of the time-delayed signal and autocorrelation power spectrum And calculate the weight h of the directional enhancement filter.

[0075]

[0076] Among them, V i and V j The signal after time delay is represented by N, where N is the number of microphones, and the cross-correlation power spectrum is... The calculation method is the same as the time delay estimation method mentioned above.

[0077] After obtaining the enhanced signal, the process also includes:

[0078] Acquire enhanced signals.

[0079] A perturbation signal is superimposed on the enhanced signal to obtain the playback signal.

[0080] Output audio signal.

[0081] The disturbance signal is obtained by filtering the short-time Fourier spectrum of the enhanced signal, i.e., multiplying the short-time Fourier spectrum of the enhanced signal by a complex exponential phase correction term, which gives:

[0082] f represents the frequency unit, and k represents the frame index.

[0083] Phase correction item It consists of two parts: a time-invariant component and a periodic time-varying component, both measured in Hz.

[0084] The sampling frequency is f s The sampling frame shift is R, and the modulation frequency is f. m The amplitude is a(f), and the constant displacement is f. v (f), This is the initial phase.

[0085] Its function is that the perturbation signal can disrupt the correlation between the pickup and playback signals, allowing the playback signal to be effectively filtered out from the pickup signal, fundamentally suppressing feedback. It also does not damage the sound components, thus ensuring that the sound is not distorted, improving signal quality and the system's anti-feedback capability. (Refer to...) Figure 3 The image shows a comparison before and after the disturbance signal is superimposed. When the disturbance signal is not superimposed, the system can generate a howling sound. After the disturbance signal is superimposed, the signal still maintains its original waveform and is not distorted.

[0086] In one embodiment, a directional enhancement local loudspeaker system is provided, referring to... Figure 4 It includes: a signal acquisition module 10, used to acquire N+1 microphone signals, where N is greater than or equal to 4.

[0087] The time delay estimation module 20 is used to estimate the time delay of the N+1 microphone signals, obtain the time delay signals of the N+1 channels, and determine the location of the target sound source.

[0088] The calculation module 30 is used to obtain a directional enhancement filter based on the time-delay signal.

[0089] Application module 40 is used to apply a directional enhancement filter to a time-delayed signal to obtain an enhanced signal.

[0090] Its function is as follows: the signal acquisition module 10 acquires N+1 microphone signals, the time delay estimation module 20 estimates the time delay of the microphone signals based on cross-correlation, determines the position of the target sound source, and aligns the N+1 microphone signals to obtain N+1 time delay signals, the calculation module 30 calculates a directional enhancement filter on the time delay signal, and the application module 40 applies the directional enhancement filter to the time delay signal to obtain a signal that enhances the target sound.

[0091] Reference Figure 5 The N+1 microphone signals correspond to N+1 microphones, including one center microphone and N surround microphones. The N surround microphones are evenly spaced and arranged in a ring on the plane. The center microphone is located at the central axis of the ring plane formed by the N surround microphones. The center microphone is suspended from the ceiling by a connecting rod or placed on the ground by a mounting bracket.

[0092] Its function is to enable the speaker's voice to be picked up by the microphone from all directions, thereby obtaining more sound signals to better locate the sound source. In addition, the center microphone is set up in this way so that the speaker does not need to hold the microphone, making it convenient to use.

[0093] For specific limitations regarding a directional enhancement local loudspeaker system, please refer to the limitations described above, which will not be repeated here. The modules in the aforementioned directional enhancement local loudspeaker system can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor within the device in hardware form, or stored in the device's memory in software form, so that the processor can call and execute the corresponding operations of each module.

[0094] In one embodiment, a device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 6 As shown, the device includes a processor, memory, network interface, and database connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The database contains data related to a directional enhancement local amplification method. The network interface is used for communication with external terminals via a network connection. The computer program, when executed by the processor, implements a directional enhancement local amplification method.

[0095] In one embodiment, a device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements a directional enhancement local amplification method according to the above embodiments, for example... Figure 1 Steps S10 to S40 are shown. Alternatively, when the processor executes the computer program, it implements the functions of each module / unit of the directional enhancement local loudspeaker device in the above embodiments, for example... Figure 4 The functions of modules 10 to 40 are shown. To avoid repetition, they will not be described again here.

[0096] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When executed by a processor, the computer program implements a directional enhancement local amplification method according to the above embodiment, for example... Figure 1 Steps S10 to S40 are shown. Alternatively, when the computer program is executed by the processor, it implements the functions of each module / unit in a directional enhancement local loudspeaker device according to the above-described device embodiments, for example... Figure 4 The functions of modules 10 to 40 are shown. To avoid repetition, they will not be described again here.

[0097] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments of this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (RON), programmable RON (PRON), electrically programmable RON (EPRON), electrically erasable programmable RON (EEPRON), or flash memory. Volatile memory may include random access memory (RAN) or external cache memory. By way of illustration and not limitation, RAN is available in a variety of forms, such as Static RAN (SRAN), Dynamic RAN (DRAN), Synchronous DRAN (SDRAN), Dual Data Rate SDRAN (DDRSDRAN), Enhanced SDRAN (ESDRAN), Synchronous Link DRAN (SLDRAN), Memory Bus Direct RAN (RDRAN), Direct Memory Bus Dynamic RAN (DRDRAN), and Memory Bus Dynamic RAN (RDRAN), etc.

[0098] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0099] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for directional enhancement of local loudspeaker amplification, characterized in that, Includes the following steps: Acquire N+1 microphone signals, where N is greater than or equal to 4; Time delay estimation is performed on the N+1 microphone signals to obtain and determine the time delay signals of the N+1 channels. The location of the target sound source; Based on the time-delay signal, a directional enhancement filter is obtained; The directional enhancement filter is applied to the time-delay signal to obtain an enhanced signal; After obtaining the enhanced signal, the process also includes: A perturbation signal is superimposed on the enhanced signal to obtain a playback signal; The step of obtaining the directional enhancement filter based on the time-delay signal includes: Obtain the cross-correlation power spectral density between the time-delayed signals, and then analyze the cross-correlation power spectral density. The average cross-correlation signal is obtained by averaging, and the real part of the average cross-correlation signal is obtained. Obtain the autocorrelation power spectral density of the time-delayed signal, and calculate the autocorrelation power spectral density. The average value of the autocorrelation signal is obtained by averaging. The ratio of the real part of the cross-correlation average signal to the autocorrelation average signal at frequency points. Values ​​are used as directional enhancement filters; The superimposed disturbance signal includes: The short-time Fourier spectrum of the enhanced signal is filtered to obtain the perturbation signal; The filtering of the short-time Fourier spectrum of the enhanced signal includes: The short-time Fourier spectrum of the enhanced signal is multiplied by a complex exponential phase correction term, the phase... The position correction term includes time-invariant components and periodic time-varying components; The step of applying the directional enhancement filter to the time-delay signal to obtain an enhanced signal includes: The directional enhancement filter directionally enhances the speaker's voice on the time-delay signal and... The interference signal is weakened, with the main signal enhancement range being 3dB-6dB and the interference signal reduction range being 10dB-13dB. Obtain the directional pickup and enhancement signal of the speaker's voice.

2. A directional enhancement local loudspeaker system, characterized in that, Using the directional enhancement local amplification method as described in claim 1, including The signal acquisition module is used to acquire N+1 microphone signals, where N is greater than or equal to 4. The time delay estimation module is used to estimate the time delay of the N+1 microphone signals to obtain N+1. The time delay signal of the road is used to determine the location of the target sound source; The calculation module is used to obtain a directional enhancement filter based on the time-delay signal; The application module is used to apply the directional enhancement filter to the time-delay signal to obtain an enhanced signal.

3. The directional enhancement local loudspeaker system according to claim 2, characterized in that, The N+1 microphone signals correspond to N+1 microphones, wherein the N+1 microphones include one center microphone and N surround microphones, wherein: The N surround microphones are equally spaced and arranged in a ring on a plane, with the central microphone located at... The central axis position of the annular plane formed by the N surrounding microphones.

4. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the directional enhancement local amplification method as described in claim 1.

5. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the directional enhancement local amplification method as described in claim 1.

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