Bilateral area isolated array receiving device

Abstract

The invention discloses an array receiving device with isolated regions on two sides. Comprising a first plane microphone array, a second plane microphone array, a first analog / digital conversion array module, a second analog / digital conversion array module, a middle plane solid damping layer, a common digital signal array processing module, a first direction digital audio output module, a second direction digital audio output module and microphone sub-array elements. Accurate separation and clear pointing of positive and negative areas can be realized in a complex sound field, the problems of area audio frequency separation, noise suppression, structural resonance interference and the like of a traditional microphone array are solved, and the method can be widely applied to the field of audio frequency receiving.

Description

Technical Field

[0001] The present invention relates to the field of audio signal reception, and particularly to an array receiving device with bilateral area isolation. Background Art

[0002] With the wide application of audio acquisition technology, directional microphones play a key role in scenarios such as conference systems, speech recognition, and environmental monitoring. Traditional directional microphones (such as cardioid and shotgun) achieve direction selectivity through physical structures or acoustic designs, but still have significant defects in many aspects.

[0003] In terms of direction suppression, although cardioid microphones can attenuate noise from the sides and rear, in a complex sound field environment, interfering sound waves from the rear direction can still enter the signal through side lobes, resulting in a decrease in signal-to-noise ratio; shotgun microphones rely on an interference tube structure, which can improve directivity, but the directivity in the low-frequency band is significantly weakened, making it difficult to effectively suppress mid-low frequency interference.

[0004] In terms of multi-directional noise dynamic processing, existing array microphone systems mostly adopt unidirectional beamforming technology to focus on a single-direction sound source, but cannot dynamically cancel reverse noise in real time. For example, in a two-way conversation scenario, traditional arrays are difficult to synchronously isolate interference from both the front and back sides, resulting in impure extraction of the target sound source.

[0005] In terms of related acoustic effects, improper design of the microphone array spacing is likely to cause the low-frequency proximity effect or high-frequency aliasing effect, resulting in signal distortion. Especially in an enclosed space, sound wave reflection and standing wave effects further exacerbate the signal aliasing phenomenon, leading to various distortion problems.

[0006] For existing noise reduction and sound collection solutions centered on phased array technology, the processing at the receiving end still relies on the design of passive filtering algorithms or fixed-direction beamforming algorithms, lacking two-way dynamic cancellation capabilities, and it is also difficult to adapt to a dynamic sound field environment. Moreover, in the low-frequency band, phase cancellation failure is likely to occur due to improper array element spacing.

[0007] Therefore, an array receiving device that supports two-way dynamic noise suppression is needed, which can accurately isolate sound waves in the front and back regions in a complex sound field, while avoiding high-frequency spatial aliasing effects and excessive feedback delay problems, and improving the quality of voice collection. Summary of the Invention

[0008] To solve the above problems, the present invention provides an array receiving device with bilateral area isolation.

[0009] The technical solution adopted by the present invention is as follows:

[0010] An array receiving device with bilateral area isolation, characterized by comprising:

[0011] The first planar microphone array is provided with a plurality of microphone sub-elements and is used for receiving acoustic wave signals in a first direction;

[0012] The second planar microphone array is provided with a plurality of microphone sub-elements, is arranged in parallel and back-to-back at an interval with the first planar microphone array, and is used for receiving acoustic wave signals in a second direction;

[0013] The first analog / digital conversion array module is connected to the first planar microphone array one by one and is used for converting the acoustic analog signals at each element position in the first direction into a first-direction digital signal group;

[0014] The second analog / digital conversion array module is connected to the second planar microphone array one by one and is used for converting the acoustic analog signals at each element position in the second direction into a second-direction digital signal group;

[0015] The middle-plane solid damping layer is respectively arranged on the back of the first planar microphone array and the back of the second planar microphone array and is used for suppressing the acoustic-solid resonance of the first and second planar microphone arrays.

[0016] The shared digital signal array processing module is respectively connected to the first analog / digital conversion array module and the second analog / digital conversion array module;

[0017] The first-direction digital audio output module is connected to the shared digital signal array processing module and is used for outputting the processed first-direction audio signal;

[0018] The second-direction digital audio output module is connected to the shared digital signal array processing module and is used for outputting the processed second-direction audio signal;

[0019] Wherein, the shared digital signal array processing module is configured to: process the second-direction digital signal group and then superimpose it on the first-direction digital signal group to suppress the interfering acoustic waves incoming from the second direction, and output the first-direction audio signal after processing; process the first-direction digital signal group and then superimpose it on the second-direction digital signal group to suppress the interfering acoustic waves incoming from the first direction, and output the second-direction audio signal after processing; the interval distance between the first planar microphone array and the second planar microphone array is set based on the frequency response range and corresponding wavelength of the target audio signal.

[0020] It is characterized in that it further includes: the element arrangement modes of the first planar microphone array and the second planar microphone array are two-dimensional planar arrays, and their arrangement structures are symmetrical to each other.

[0021] Preferably, the processing of the signal group by the shared digital signal array processing module includes operations such as time delay, amplitude-frequency weighting, phase-frequency weighting, phase inversion, basic signal operations, and threshold clipping.

[0022] Preferably, the processing processes for generating the first and second direction audio signals in the shared digital signal array processing module are allowed to be different and are allowed to be adjusted in real time.

[0023] Preferably, the spacing distance between every two microphone sub-elements on the same planar array is not higher than half of the wavelength of the upper limit of the device response frequency, so as to satisfy the spatial sampling theorem and avoid the spatial aliasing effect of high-frequency signals.

[0024] Preferably, the spacing distance between the first planar microphone array and the second planar microphone array is not higher than the wavelength of the upper limit of the device response frequency, so as to avoid too long feedback delay.

[0025] Preferably, the solid resonance frequency distribution of the middle-plane solid damping layer is different from the solid resonance frequency points, resonance peaks, and resonance Q values of the first and second planar microphone arrays.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] The array receiving device with bilateral area isolation according to the present invention uses the first planar microphone array and the second planar microphone array to be arranged in parallel and spaced apart back to back, and the element arrangements of the two are symmetric to each other, respectively receiving the first direction signal group and the second direction signal group, and in the shared digital signal array processing module, the second direction audio signal after being processed such as time delay, attenuation, weighting, and phase is anti-phase superimposed on the first direction digital signal group, so as to dynamically cancel the sound coming from the area in the second direction and only receive the sound wave in the area in the first direction; similarly, the second planar microphone array can also use the received signal of the first planar microphone array for dynamic cancellation to achieve real-time and accurate audio reception of the back area.

[0028] At the same time, since a middle-plane solid damping layer is provided on the back sides of the first and second planar microphone arrays, and its solid resonance frequency distribution characteristics are mismatched with the resonance frequency distribution characteristics of the array itself, a composite plate vibration structure is jointly formed with the planar array part. According to the physical theory of the composite sandwich plate, this structure can enhance the resistance of the device to super-resonance and sub-resonance under the excitation vibration of broadband signals; since the resonance frequency of the middle-plane solid damping layer is separated from the natural frequency of the microphone array, the resonance energy transfer process can be effectively suppressed, thereby weakening the problem of acoustic-solid coupling resonance excitation caused by strong sound pressure signals and improving the signal-to-noise ratio and audio directivity.

[0029] In addition, the distance d between the microphone sub-array elements within the same planar array is not higher than half of the wavelength of the upper limit of the device response frequency, that is, it satisfies It can satisfy the spatial sampling theorem and avoid the phase distortion problem caused by spatial aliasing of high-frequency signals; the distance D between the planar arrays is not higher than the wavelength of the upper limit of the response frequency, that is, it satisfies D ≤ λ MAX , preventing the pseudo-echo problem caused by too long feedback delay of the back signal.

[0030] Considering the above three aspects comprehensively, finally, the device can achieve accurate separation and clear directional reception of sound waves in the positive and negative regions in a complex sound field, while avoiding various distortion problems brought by high-frequency spatial aliasing effects and too long feedback delays, solving the technical bottlenecks of traditional microphone arrays in aspects such as back-region audio separation and noise suppression, structural resonance interference, and frequency band response, and providing a general solution with high precision, accurate regional separation, and clear directional reception. Brief Description of the Drawings

[0031] Figure 1 is a schematic diagram of the signal structure of an array receiving device with bilateral regional isolation according to the present invention

[0032] Figure 2 is a physical assembly example diagram of an array receiving device with bilateral regional isolation according to the present invention

[0033] First planar microphone array, 2. Second planar microphone array, 3. First analog / digital conversion array module, 4. Second analog / digital conversion array module, 5. First direction digital signal group, 6. Second direction digital signal group, 7. Middle-plane solid damping layer, 8. Shared digital signal array processing module, 9. First direction audio signal, 10. Second direction audio signal, 11. First direction digital audio output module, 12. Second direction digital audio output module, 13. Microphone sub-array element Detailed Embodiment

[0034] For the convenience of description, the following is combined with Figure 1 , Figure 2 to describe an array receiving device with bilateral regional isolation according to the present invention. Similar components in the drawings are represented by the same or similar reference numerals. Those skilled in the art should understand that the specific case content described below is illustrative rather than restrictive, and should not be used to limit the protection scope of the present invention.

[0035] See Figure 1 , Figure 2As shown in the figure, to solve the above problems, an embodiment of the present invention provides an array receiving device with bilateral area isolation, including a first planar microphone array 1, which is provided with a plurality of microphone sub-elements 13 for receiving acoustic wave signals in a first direction; a first planar microphone array 2, which is provided with a plurality of microphone sub-elements 13, is arranged in parallel and at a spaced distance from the first planar microphone array 1 in the opposite direction for receiving acoustic wave signals in a second direction; a first analog / digital conversion array module 3, which is connected to the first planar microphone array 1 one by one, for converting the acoustic analog signals at each element position in the first direction into a first-direction digital signal group 5; a first analog / digital conversion array module 4, which is connected to the first planar microphone array 2 one by one, for converting the acoustic analog signals at each element position in the second direction into a second-direction digital signal group 6; a middle-plane solid damping layer 7, which is respectively arranged on the back of the first planar microphone array 1 and the back of the first planar microphone array 2 for suppressing the acoustic-solid resonance of the first and second planar microphone arrays 1 and 2. A shared digital signal array processing module 8, which is respectively connected to the first analog / digital conversion array module 3 and the first analog / digital conversion array module 4; a first-direction digital audio output module 11, which is connected to the shared digital signal array processing module 8 for outputting the processed first-direction audio signal 9; a second-direction digital audio output module 12, which is connected to the shared digital signal array processing module 8 for outputting the processed second-direction audio signal 10; wherein, the shared digital signal array processing module 8 is configured to: process the second-direction digital signal group 6 and then superimpose it on the first-direction digital signal group 5 to suppress the interfering acoustic waves incoming from the second direction, and output the first-direction audio signal 9 after processing; process the first-direction digital signal group 5 and then superimpose it on the second-direction digital signal group 6 to suppress the interfering acoustic waves incoming from the first direction, and output the second-direction audio signal 10 after processing; the spacing distance between the first planar microphone array 1 and the first planar microphone array 2 is set based on the frequency response range and corresponding wavelength of the target audio signal.

[0036] Among them, the arrangement mode of the sub-elements of the first planar microphone array 1 and the first planar microphone array 2 is a two-dimensional planar array, and the specific distribution form of the microphone sub-elements 13 on each planar array can present an array arrangement in the form of a rectangle, a triangle, a hexagon, a multi-arm spiral or other forms, and the arrangement structures of the two planar arrays are symmetrical to each other.

[0037] This embodiment further includes: The processing of the signal group by the shared digital signal array processing module 8 includes operations such as time delay, amplitude-frequency weighting, phase-frequency weighting, phase inversion, basic signal operations, and threshold clipping; The time delay algorithm part is designed based on the time difference of the wave paths when the sound source propagates to each microphone sub-element 13. When the sampling rates of the analog / digital conversion array modules and the digital signal array processing module inside the device are not less than 48 kHz, the time delay resolution can be ensured to be less than 0.1 ms; The amplitude-frequency weighting algorithm is calculated based on the frequency transfer functions of the same-site sound source reaching the first planar microphone array 1 and the first planar microphone array 2. Therefore, this filtering and weighting algorithm should measure and superimpose the transfer function curve on the basis of conventional weighting algorithms such as Chebyshev weighting and Taylor weighting, so as to effectively compensate for the amplitude-frequency and phase-frequency differences of the same-site sound source in the two receiving planes in different orientations, and improve the fitting degree and robustness of the anti-phase signal cancellation after processing.

[0038] In the shared digital signal array processing module 8, the processing processes for generating the first and second direction audio signals 9 and 10 are allowed to be different to obtain audio beams at different angles and regions on the front and back sides. Combining external software control or hardware manual control to perform real-time adjustment of the time delay of the signal group, etc., can achieve effects such as audio capture and locking of a moving dynamic sound source.

[0039] The interval distance d between every two of the microphone sub-elements 13 located on the same planar array is not higher than half of the upper limit of the device response frequency, that is, it satisfies to satisfy the spatial sampling theorem and avoid the phase distortion problem caused by spatial aliasing of high-frequency signals.

[0040] The interval distance D between the first planar microphone array 1 and the first planar microphone array 2 is not higher than the wavelength of the upper limit of the device response frequency, that is, it satisfies D≤λ MAX , preventing the pseudo-echo problem caused by too long back signal feedback delay.

[0041] The solid resonance frequency distribution of the middle solid damping layer 7 is different from the solid resonance frequency points, resonance peaks, and resonance Q values of the first and second planar microphone arrays 1 and 2. Its solid resonance frequency distribution characteristics are mismatched with the self-resonance frequency distribution characteristics of the two arrays, so as to jointly form a composite plate vibration structure with the two planar arrays. According to the physical theory of the composite sandwich plate, this structure can enhance the device's resistance to super-resonance and sub-resonance under the excitation vibration of broadband signals; At the same time, since the resonance frequency of the middle solid damping layer 7 is separated from the inherent frequency of the microphone array, it can effectively suppress the resonance energy transfer process, thereby weakening the problem of acoustic-solid coupling resonance excitation caused by strong sound pressure signals, and high signal-to-noise ratio and audio directivity can also be achieved in application scenarios with complex acoustic conditions and large volume.

[0042] Considering the above three aspects, the device can finally achieve precise separation and clear directional reception of sound waves in the forward and reverse regions in a complex sound field, while avoiding various distortion problems caused by high-frequency spatial aliasing effects and excessive feedback delays. It solves the technical bottlenecks of traditional microphone arrays in aspects such as audio separation and noise suppression in the backward region, structural resonance interference, and frequency band response, achieving a general-purpose, high-precision, precise regional separation, and clear directional audio reception effect, with broad application prospects.

[0043] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, based on the above description, other different forms of changes or modifications can be made. It is impossible to enumerate all the implementation manners here. Any obvious changes or modifications derived from the technical solutions of the present invention still fall within the protection scope of the present invention.

Claims

1. An array receiving device with double-side area isolation, characterized in that: include: A first planar microphone array is provided with a plurality of microphone sub-array elements for receiving a sound wave signal in a first direction; A second planar microphone array is provided with a plurality of microphone sub-array elements, which are arranged in parallel and back-to-back with the first planar microphone array and are used to receive sound wave signals in a second direction; A first analog / digital conversion array module is connected to the first planar microphone array one by one and is used to convert the sound wave analog signal of each array element point in the first direction into a first direction digital signal group; A second analog / digital conversion array module is connected to the second planar microphone array one by one, and is used to convert the sound wave analog signal of each array element point in the second direction into a second direction digital signal group; The mid-surface solid damping layer is respectively arranged on the back side of the first planar microphone array and the back side of the second planar microphone array, and is used to suppress the acoustic-solid resonance of the first and second planar microphone arrays. A common digital signal array processing module, connected to the first analog / digital conversion array module and the second analog / digital conversion array module respectively; A first direction digital audio output module, connected to the common digital signal array processing module, for outputting a processed first direction audio signal; A second direction digital audio output module, connected to the common digital signal array processing module, for outputting a processed second direction audio signal; Among them, the shared digital signal array processing module is configured to: process the second direction digital signal group and then superimpose it to the first direction digital signal group to suppress the interference sound waves transmitted from the second direction, and output the first direction audio signal after processing; process the first direction digital signal group and then superimpose it to the second direction digital signal group to suppress the interference sound waves transmitted from the first direction, and output the second direction audio signal after processing; the spacing distance between the first planar microphone array and the second planar microphone array is set based on the frequency response range and corresponding wavelength of the target audio signal.

2. The array receiving device with double-side area isolation according to claim 1, characterized in that: The array elements of the first planar microphone array and the second planar microphone array are arranged in a two-dimensional planar array, and the arrangement structures of the two are symmetrical to each other.

3. The array receiving device with double-side area isolation according to claim 2, characterized in that: The processing of the signal group by the common digital signal array processing module includes operations such as timing delay, amplitude-frequency weighting, phase-frequency weighting, phase inversion, basic signal operations and threshold compression.

4. The array receiving device with double-side area isolation according to claim 3, characterized in that: The processing procedures for generating the first and second directional audio signals in the common digital signal array processing module are allowed to be different and can be adjusted in real time.

5. The array receiving device with double-side area isolation according to claim 2, characterized in that: The spacing distance between every two microphone sub-array elements located on the same plane array is no greater than half the wavelength of the upper limit of the device response frequency.

6. The array receiving device with double-side area isolation according to claim 2, characterized in that: The distance between the first planar microphone array and the second planar microphone array is no greater than the wavelength of the upper limit of the device response frequency.

7. The array receiving device with double-side area isolation according to claim 2, characterized in that: The solid resonance frequency distribution of the mid-surface solid damping layer is different from the solid resonance frequency distribution of the first and second planar microphone arrays.

Images