A method and apparatus for directional sound transmission

Abstract

The application discloses a directional sound transmission method and a directional device, which comprises the following steps: performing analog-digital conversion on an original audio signal, performing multi-resolution dynamic spectrum analysis on the signal after the analog-digital conversion, and extracting a current audio signal characteristic parameter; determining an adaptive frequency division point according to the extracted characteristic parameter, dividing the audio signal into a low-frequency signal component and a high-frequency signal component; performing double-channel differential processing on the divided components to generate directional sound waves; performing time delay compensation and phase calibration on the generated directional sound waves to make the two-channel sound waves synchronously arrive at a target sound field predetermined space intersection plane; when a multi-path independent audio stream request is received, performing signal characteristic parameter extraction, adaptive division, double-channel differential processing and calibration on each input respectively, and alternately or in parallel driving a loudspeaker array in a time division or space division mode to generate multiple independent directional sound beams. The application adopts the above method and device, realizes directional sound transmission, and effectively reduces noise in a non-target region.

Description

Technical Field

[0001] This invention relates to the field of directional sound transmission technology, and in particular to a directional sound transmission method and directional device. Background Technology

[0002] Square dancing, a popular form of mass fitness and recreational activity, is often performed in public places such as parks, community squares, and open spaces. In practice, multiple dance teams often operate simultaneously in the same or adjacent areas, with each team typically using its own high-powered sound system to play its own accompaniment music. This leads to the following prominent problems: Sound interference: Music played by different teams overlaps and mixes in the air, making it difficult for dancers to hear the beat of their own team's music, leading to disordered movements and a decreased experience of the activity.

[0003] Frequent noise complaints: The sound waves of traditional speakers spread spherically, and the low-frequency energy has strong penetrating power, which can spread to high-rise residential buildings hundreds of meters away, which can easily cause complaints from surrounding residents and even trigger social conflicts.

[0004] Achieving independent sound fields in multiple areas is difficult: existing portable amplification equipment cannot simultaneously generate multiple audible sound zones that do not interfere with each other within the same physical space. Adding physical isolation or staggering the timing of activities for different teams would significantly reduce the utilization rate of the venue and the convenience of the activities.

[0005] Therefore, there is an urgent need for a directional sound transmission method and directional equipment suitable for square dancing. Summary of the Invention

[0006] The purpose of this invention is to provide a directional sound transmission method and directional device to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides a directional sound transmission method, comprising the following steps: S1. Perform analog-to-digital conversion on the original audio signal, and use a digital signal processor to perform multi-resolution dynamic spectrum analysis on the converted signal to extract the characteristic parameters of the current audio signal. S2. Based on the extracted feature parameters, the adaptive frequency division point is determined in real time according to the valley position of the probability density function of the spectral distribution, and the audio signal is divided into low-frequency signal components and high-frequency signal components. S3. Perform dual-channel differential processing on low-frequency and high-frequency signal components to generate directional sound waves; S4. Perform time delay compensation and phase calibration on the generated directional sound waves to ensure that the two channels of sound waves arrive at the predetermined spatial intersection plane of the target sound field synchronously. S5. When multiple independent audio stream requests are received, steps S1-S4 are executed for each input, driving the speaker array alternately or in parallel in time-division or space-division mode to generate multiple independent directional sound beams, and inserting virtual null constraints between adjacent beams to suppress crosstalk between adjacent beams.

[0008] Preferably, the characteristic parameters in step S1 include spectral envelope, spectral centroid, and spectral kurtosis.

[0009] Preferably, in step S2, the adaptive frequency division point is the frequency value corresponding to the local minimum of the spectral distribution probability density function between two adjacent main energy peaks.

[0010] Preferably, step S3 specifically includes: The low-frequency signal component is modulated to the ultrasonic carrier frequency band through single-sideband up-conversion to obtain an ultrasonic modulated signal. The ultrasonic modulated signal is then sent to an ultrasonic transducer array for transmission. The nonlinear demodulation effect of ultrasonic waves in the air is used to reconstruct low-frequency audible sound in front of the target area. The high-frequency signal components are sent to the phased array beamforming processing unit. The phased array beamforming processing unit adopts the least mean square class adaptive beamforming algorithm. Combining the beam maximum response direction and zero-point constraint position information, it calculates the amplitude weight and time delay corresponding to at least two loudspeaker array elements in real time to generate multiple high-frequency drive signals. Each drive signal is independently driven by at least two electrodynamic high-frequency loudspeaker array elements to generate highly directional sound waves. The anti-phase cancellation effect is used to achieve rapid attenuation of sound energy in non-target directions.

[0011] Preferably, the ultrasonic carrier frequency band is between 40 kHz and 80 kHz.

[0012] Preferably, step S4 specifically includes: based on the pre-measured or online estimated low-frequency channel ultrasonic demodulation group delay and high-frequency channel circuit signal processing channel total delay, using a global delay alignment algorithm, applying a compensation delay to the driving signals of each element of the high-frequency phased array channel, so that the sound waves of the two channels arrive at the predetermined spatial intersection plane of the target sound field synchronously.

[0013] Preferably, step S5 specifically includes: Receive requests for multiple independent audio streams and execute steps S1-S4 for each audio stream; Based on the spatial boundary constraints of the target regions of each audio stream, calculate the independent pointing vector and null constraint coordinates of each beam; Time-slice scheduling sequences or space-division multiplexing allocation parameters are issued to each phased array computing unit to drive the speaker array through time-division alternation or space-division parallelism. Virtual null constraint directions are added between adjacent beams to reduce audible crosstalk between adjacent beams. The virtual null constraint directions are determined based on the spatial boundary of the target area of ​​adjacent beams.

[0014] The present invention also provides a directional device for performing the above-described directional sound transmission method, comprising: The audio acquisition module is used to receive the raw audio signal; The analog-to-digital conversion module, connected to the audio acquisition module, is used to perform analog-to-digital conversion on the original audio signal; A digital signal processor, connected to an analog-to-digital converter module, is used to perform multi-resolution dynamic spectrum analysis on the converted signal, extract the characteristic parameters of the current audio signal, and divide the audio signal into low-frequency signal components and high-frequency signal components based on the characteristic parameters. A dual-channel differential processing module, connected to a digital signal processor, is used to differentially process low-frequency and high-frequency signal components to generate directional sound waves. The delay calibration module, connected to the dual-channel differential processing module, is used to perform time delay compensation and phase calibration on the generated directional sound waves, so that the sound waves of the two channels arrive at the predetermined spatial intersection plane of the target sound field synchronously. The multi-channel audio stream scheduling controller is connected to the audio acquisition module. When it receives multiple independent audio stream requests, it activates the digital signal processor, dual-channel differential processing module and delay calibration module for each input, and drives the speaker array alternately or in parallel in time-division or space-division mode to generate multiple independent directional sound beams.

[0015] Preferably, the dual-channel differential processing module includes: The low-frequency channel processing unit is used to convert the low-frequency signal components to the ultrasonic carrier frequency band through single-sideband up-conversion modulation and output the ultrasonic modulated signal. The phased array beamforming processing unit is used to receive high-frequency signal components and adopts the least mean square class adaptive beamforming algorithm. It combines the beam maximum response direction and null constraint position information to calculate the amplitude weight and time delay of at least two loudspeaker array elements in real time and generate multiple high-frequency drive signals. Loudspeaker arrays, including ultrasonic transducer arrays and electrodynamic high-frequency loudspeaker arrays; An ultrasonic transducer array, connected to a low-frequency channel processing unit, is used to transmit ultrasonic modulated signals and utilize the nonlinear demodulation effect in the air to reproduce low-frequency audible sound in front of the target area. An electric high-frequency loudspeaker array consists of at least two loudspeaker elements, each of which is connected to the corresponding drive signal output terminal of a phased array beamforming processing unit for independently driving and generating highly directional sound waves.

[0016] Therefore, the present invention, employing the above-described directional sound transmission method and directional device, has the following beneficial effects: (1) By adaptive frequency division and dual-channel differential processing, the audio signal is efficiently divided into low-frequency and high-frequency components. After the low frequency is transmitted by ultrasonic carrier modulation, it is naturally demodulated and restored in front of the target area, and the spatial coverage range is controllable. The high frequency forms a sharp directional beam through phased array beamforming. Multiple independent audio streams request to drive the speaker array through time division or space division mode, and virtual zero point constraints are added between adjacent beams to generate independent sound waves, reducing the interference in adjacent areas.

[0017] (2) The directional sound waves generated by this method have their energy mainly concentrated in the target activity area, and the sound energy in non-target directions decays rapidly, effectively reducing noise.

[0018] (3) Through the multi-channel audio stream scheduling controller and the virtual zero-point constraint algorithm, the speaker array of the present invention can generate multiple independent directional sound beams simultaneously or alternately, and each beam can carry completely different audio content.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating an embodiment of a directional sound transmission method according to the present invention. Figure 2 This is a system framework diagram of an embodiment of a directional device according to the present invention. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0023] Example like Figure 1 As shown, the present invention provides a directional sound transmission method, comprising the following steps: S1. Perform analog-to-digital conversion on the original audio signal, and use a digital signal processor to perform multi-resolution dynamic spectrum analysis on the converted signal to extract characteristic parameters such as the spectral envelope, spectral centroid, and spectral kurtosis of the current audio signal.

[0024] S2. Based on the extracted feature parameters, the adaptive frequency division point is determined in real time according to the valley position of the spectral probability density function, dividing the audio signal into low-frequency and high-frequency signal components. The adaptive frequency division point is the frequency value corresponding to the local minimum of the spectral probability density function between two adjacent main energy peaks. Through adaptive segmentation, the frequency division position can be dynamically determined according to the spectral structure characteristics of the audio content, ensuring accurate matching between the real-time signal and the frequency division point.

[0025] S3. Perform dual-channel differential processing on the low-frequency and high-frequency signal components to generate directional sound waves. Specifically, this includes: The low-frequency signal component is modulated to the ultrasonic carrier frequency band through single-sideband up-conversion to obtain an ultrasonic modulated signal. The ultrasonic modulated signal is then sent to an ultrasonic transducer array for transmission. By utilizing the nonlinear demodulation effect of ultrasonic waves in the air, a low-frequency audible sound is reproduced in front of the target area. The ultrasonic carrier frequency band is between 40kHz and 80kHz.

[0026] The high-frequency signal components are fed into the phased array beamforming processing unit. The phased array beamforming processing unit adopts the least mean square class adaptive beamforming algorithm. Combining the beam maximum response direction and zero-point constraint position information, it calculates the amplitude weight and time delay corresponding to at least two loudspeaker array elements in real time, and generates multiple high-frequency driving signals. Each driving signal is amplified by an independent DAC digital-to-analog conversion channel and an independent power amplifier AMP, and drives at least two loudspeaker array elements to form a highly directional sound wave beam in the specified direction. In the non-target direction, the anti-phase cancellation effect is used to achieve rapid attenuation of sound energy.

[0027] S4. Perform time delay compensation and phase calibration on the generated directional sound waves to ensure that the sound waves from both channels arrive at the predetermined spatial intersection plane of the target sound field synchronously. Specifically, this includes: based on the pre-measured or online estimated group delay of the low-frequency channel ultrasonic demodulation and the total delay of the high-frequency channel circuit signal processing channel, using a global delay alignment algorithm, applying compensation time delay to the driving signals of each element in the high-frequency phased array channel to ensure that the sound waves from both channels arrive at the predetermined spatial intersection plane of the target sound field synchronously.

[0028] S5. When multiple independent audio stream requests are received, steps S1-S4 are executed for each input, driving the speaker array alternately or in parallel in time-division or space-division mode to generate multiple independent directional acoustic beams. Virtual null constraints are inserted between adjacent beams to suppress crosstalk between adjacent beams. Specifically, this includes: Receive requests for multiple independent audio streams and execute steps S1-S4 for each audio stream; Based on the spatial boundary constraints of the target regions of each audio stream, calculate the independent pointing vector and null constraint coordinates of each beam; Time-slice scheduling sequences or space-division multiplexing allocation parameters are issued to each phased array computing unit to drive the speaker array through time-division alternation or space-division parallelism. Virtual null constraint directions are added between adjacent beams to reduce audible crosstalk between adjacent beams. The virtual null constraint directions are determined based on the spatial boundary of the target area of ​​adjacent beams.

[0029] like Figure 2 As shown, the present invention also provides an orientation device, comprising: The audio acquisition module includes interfaces for USB flash drive, Bluetooth, TF card, AUX, microphone, electric guitar, and electric saxophone, used to receive raw audio signals.

[0030] The analog-to-digital conversion module, connected to the audio acquisition module, is used to perform analog-to-digital conversion on the original audio signal; A digital signal processor, connected to an analog-to-digital converter module, is used to perform multi-resolution dynamic spectrum analysis on the converted signal, extract the characteristic parameters of the current audio signal, and divide the audio signal into low-frequency signal components and high-frequency signal components based on the characteristic parameters. A dual-channel differential processing module, connected to a digital signal processor, is used to differentially process low-frequency and high-frequency signal components to generate directional sound waves. The delay calibration module, connected to the dual-channel differential processing module, is used to perform time delay compensation and phase calibration on the generated directional sound waves, so that the sound waves of the two channels arrive at the predetermined spatial intersection plane of the target sound field synchronously. The multi-channel audio stream scheduling controller is connected to the audio acquisition module. When it receives multiple independent audio stream requests, it activates the digital signal processor, dual-channel differential processing module and delay calibration module for each input, and drives the speaker array alternately or in parallel in time-division or space-division mode to generate multiple independent directional sound beams.

[0031] In this embodiment, the dual-channel differentiation processing module includes: The low-frequency channel processing unit is used to convert the low-frequency signal components to the ultrasonic carrier frequency band through single-sideband up-conversion modulation and output the ultrasonic modulated signal. The phased array beamforming processing unit is used to receive high-frequency signal components and adopts the least mean square class adaptive beamforming algorithm. It combines the beam maximum response direction and null constraint position information to calculate the amplitude weight and time delay of at least two loudspeaker array elements in real time and generate multiple high-frequency drive signals. Loudspeaker arrays, including ultrasonic transducer arrays and electrodynamic high-frequency loudspeaker arrays; An ultrasonic transducer array, connected to a low-frequency channel processing unit, is used to transmit ultrasonic modulated signals and utilize the nonlinear demodulation effect in the air to reproduce low-frequency audible sound in front of the target area. An electric high-frequency loudspeaker array consists of at least two loudspeaker elements, each of which is connected to the corresponding drive signal output terminal of a phased array beamforming processing unit for independently driving and generating highly directional sound waves.

[0032] To verify the effectiveness of the method of the present invention, the differences in the angle of the sound-emitting area and the before-and-after differences are used for illustration. Specifically, as follows: Test scenario: Target area: The area with the acoustic center of the loudspeaker array as the origin, and the angular coverage range is defined as ±15° (total width 30°).

[0033] Non-target area: At the same distance, the area beyond ±35° horizontal angle and the area behind it.

[0034] Test equipment: Loudspeaker arrays: ultrasonic transducer array (center frequency 40kHz, element spacing λ / 2), electrodynamic high-frequency loudspeaker array (8-unit linear array). Power amplifier: Low frequency channel: 50W@40kHz; High frequency channel: 100W@2kHz–20kHz; Signal generator, multi-channel arbitrary waveform generator, sampling rate ≥192kHz, resolution 24bit; Test results: The main sound-emitting area has a directional sound beam coverage angle of ≤25°, with energy highly concentrated in the target area, covering only a small space where the square dance team is located.

[0035] In non-target areas, the sound energy at the outside angle of the beam decays rapidly, and there is basically no effective audible sound outside ±35°, thus avoiding large-scale sound diffusion.

[0036] In multi-beam scenarios, multiple independent beams are constrained by virtual null points, and there is no crosstalk between adjacent beam boundary angles, enabling independent sound generation in multiple areas of the same venue.

[0037] Directional sound transmission effect, with a difference of ≥30dB before and after.

[0038] Therefore, the present invention employs the above-mentioned directional sound transmission method and directional device to achieve directional sound transmission and effectively reduce noise in non-target areas.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for directional sound transmission, characterized in that, Includes the following steps: S1. Perform analog-to-digital conversion on the original audio signal, and use a digital signal processor to perform multi-resolution dynamic spectrum analysis on the converted signal to extract the characteristic parameters of the current audio signal. S2. Based on the extracted feature parameters, the adaptive frequency division point is determined in real time according to the valley position of the probability density function of the spectral distribution, and the audio signal is divided into low-frequency signal components and high-frequency signal components. S3. Perform dual-channel differential processing on low-frequency and high-frequency signal components to generate directional sound waves; S4. Perform time delay compensation and phase calibration on the generated directional sound waves to ensure that the two channels of sound waves arrive at the predetermined spatial intersection plane of the target sound field synchronously. S5. When multiple independent audio stream requests are received, steps S1-S4 are executed for each input, driving the speaker array alternately or in parallel in time-division or space-division mode to generate multiple independent directional sound beams, and inserting virtual null constraints between adjacent beams to suppress crosstalk between adjacent beams.

2. The directional sound transmission method according to claim 1, characterized in that: The characteristic parameters in step S1 include spectral envelope, spectral centroid, and spectral kurtosis.

3. The directional sound transmission method according to claim 1, characterized in that: In step S2, the adaptive frequency division point is the frequency value corresponding to the local minimum value of the spectral distribution probability density function between two adjacent main energy peaks.

4. The directional sound transmission method according to claim 1, characterized in that: Step S3 specifically includes: The low-frequency signal component is modulated to the ultrasonic carrier frequency band through single-sideband up-conversion to obtain an ultrasonic modulated signal. The ultrasonic modulated signal is then sent to an ultrasonic transducer array for transmission. The nonlinear demodulation effect of ultrasonic waves in the air is used to reconstruct low-frequency audible sound in front of the target area. The high-frequency signal components are sent to the phased array beamforming processing unit. The phased array beamforming processing unit adopts the least mean square class adaptive beamforming algorithm. Combining the beam maximum response direction and zero-point constraint position information, it calculates the amplitude weight and time delay corresponding to at least two loudspeaker array elements in real time to generate multiple high-frequency drive signals. Each drive signal is independently driven by at least two electrodynamic high-frequency loudspeaker array elements to generate highly directional sound waves. The anti-phase cancellation effect is used to achieve rapid attenuation of sound energy in non-target directions.

5. A directional sound transmission method according to claim 1, characterized in that: The ultrasonic carrier frequency band is between 40kHz and 80kHz.

6. The directional sound transmission method according to claim 1, characterized in that: Step S4 specifically includes: based on the pre-measured or online estimated low-frequency channel ultrasonic demodulation group delay and high-frequency channel circuit signal processing channel total delay, using a global delay alignment algorithm, applying compensation delay to the driving signals of each element of the high-frequency phased array channel, so that the sound waves of the two channels arrive at the predetermined spatial intersection plane of the target sound field synchronously.

7. A directional sound transmission method according to claim 6, characterized in that, Step S5 specifically includes: Receive requests for multiple independent audio streams and execute steps S1-S4 for each audio stream; Based on the spatial boundary constraints of the target regions of each audio stream, calculate the independent pointing vector and null constraint coordinates of each beam; Time-slice scheduling sequences or space-division multiplexing allocation parameters are issued to each phased array computing unit to drive the speaker array through time-division alternation or space-division parallelism. Virtual null constraint directions are added between adjacent beams to reduce audible crosstalk between adjacent beams. The virtual null constraint directions are determined based on the spatial boundary of the target area of ​​adjacent beams.

8. A directional device for performing a directional sound transmission method according to any one of claims 1-7, characterized in that, include: The audio acquisition module is used to receive the raw audio signal; The analog-to-digital conversion module, connected to the audio acquisition module, is used to perform analog-to-digital conversion on the original audio signal; A digital signal processor, connected to an analog-to-digital converter module, is used to perform multi-resolution dynamic spectrum analysis on the converted signal, extract the characteristic parameters of the current audio signal, and divide the audio signal into low-frequency signal components and high-frequency signal components based on the characteristic parameters. A dual-channel differential processing module, connected to a digital signal processor, is used to differentially process low-frequency and high-frequency signal components to generate directional sound waves. The delay calibration module, connected to the dual-channel differential processing module, is used to perform time delay compensation and phase calibration on the generated directional sound waves, so that the sound waves of the two channels arrive at the predetermined spatial intersection plane of the target sound field synchronously. The multi-channel audio stream scheduling controller is connected to the audio acquisition module. When it receives multiple independent audio stream requests, it activates the digital signal processor, dual-channel differential processing module and delay calibration module for each input, and drives the speaker array alternately or in parallel in time-division or space-division mode to generate multiple independent directional sound beams.

9. A directional device according to claim 8, characterized in that, The dual-channel differential processing module includes: The low-frequency channel processing unit is used to convert the low-frequency signal components to the ultrasonic carrier frequency band through single-sideband up-conversion modulation and output the ultrasonic modulated signal. The phased array beamforming processing unit is used to receive high-frequency signal components and adopts the least mean square class adaptive beamforming algorithm. It combines the beam maximum response direction and null constraint position information to calculate the amplitude weight and time delay of at least two loudspeaker array elements in real time and generate multiple high-frequency drive signals. Loudspeaker arrays, including ultrasonic transducer arrays and electrodynamic high-frequency loudspeaker arrays; An ultrasonic transducer array, connected to a low-frequency channel processing unit, is used to transmit ultrasonic modulated signals and utilize the nonlinear demodulation effect in the air to reproduce low-frequency audible sound in front of the target area. An electric high-frequency loudspeaker array consists of at least two loudspeaker elements, each of which is connected to the corresponding drive signal output terminal of a phased array beamforming processing unit for independently driving and generating highly directional sound waves.

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