A microphone assembly, an acoustic imaging system, and an acoustic imaging method.

Abstract

This application provides a microphone assembly, an acoustic imaging system, and an acoustic imaging method, relating to the field of acoustic imaging technology. The microphone assembly includes a support structure and multiple microphones disposed on the support structure. An opening is located at the center of the support structure. The multiple microphones are located within an annular region between a first edge of the opening and a second edge of the support structure. The greater the distance between the microphones and the opening, the lower the microphone density. The high-density distribution at the center meets the sampling requirements of short-wavelength signals in the high-frequency band, effectively suppressing high-frequency spatial aliasing, grating lobes, and strong sidelobes, reducing imaging false hotspots, and improving the accuracy of high-frequency sound source localization. The low-density distribution at the outer edges maximizes the effective physical aperture of the microphone array without increasing the component volume or the total number of microphones, enhancing the angular resolution capability in the mid-to-low frequency band and reducing mid-to-low frequency positioning ambiguity. This effectively improves the performance of the microphone assembly.

Description

Technical Field

[0001] This application relates to the field of acoustic imaging technology, and in particular to a microphone assembly, an acoustic imaging system, and an acoustic imaging method. Background Technology

[0002] Acoustic imaging devices typically acquire multi-channel acoustic signals using microphone arrays, and then use array signal processing algorithms such as beamforming to invert the energy distribution of the sound source in the spatial domain. In industrial scenarios, the main detection targets include sound sources such as compressed gas leaks, vacuum leaks, electrical equipment discharges, mechanical friction, and abnormal vibrations. These application environments generally present problems such as strong background noise, complex structural sound reflections, and long detection distances, placing high demands on the accuracy and stability of sound source localization.

[0003] However, existing portable acoustic imaging devices are limited by lightweight requirements such as size and weight, resulting in generally small microphone array apertures, which leads to insufficient spatial angular resolution in the low-frequency band. When operating in the high-frequency band, they are prone to spatial aliasing and high sidelobes, forming false sound source hotspots, thereby reducing the accuracy and reliability of sound source localization.

[0004] It is evident that existing microphone components suffer from poor performance. Summary of the Invention

[0005] This application provides a microphone assembly, an acoustic imaging system, and an acoustic imaging method to address the problem of poor performance in existing microphone assemblies.

[0006] In a first aspect, embodiments of this application provide a microphone assembly, including a support structure and a plurality of microphones disposed on the support structure. The support structure has an opening at its center, and the plurality of microphones are located in an annular region between a first edge of the opening and a second edge of the support structure. The greater the distance between the microphones and the opening, the lower the microphone distribution density.

[0007] Optionally, the plurality of microphones are arranged in a non-periodic spiral radial pattern.

[0008] Optionally, in a polar coordinate system with the center of the supporting structure as the pole, the polar coordinates of the first microphone mounted on the supporting structure are (r i θ i The first microphone is the i-th microphone among the plurality of microphones;

[0009] in, 'a' is a scaling factor used to control the overall density and array expansion speed, and 'i' is the sequential number of the first microphone; θ i=θ0+iγ, where θ0 is the initial angle and γ is the angle increment that is a non-π rational multiple.

[0010] Optionally, in a polar coordinate system with the center of the supporting structure as the pole, the polar coordinates of the first microphone mounted on the supporting structure are (r i θ i The first microphone is the i-th microphone among the plurality of microphones;

[0011] in, , 'a' is the scaling factor, used to control the overall density and array expansion speed; 'i' is the sequential number of the first microphone; 'W(·)' is the monotonic radial mapping function; θ i =θ0+iγ, where θ0 is the initial angle and γ is the angle increment that is a non-π rational multiple.

[0012] Optionally, from the first edge to the second edge, the support structure includes a first density region and a second density region, wherein the microphone density in the first density region is greater than the microphone density in the second density region;

[0013] The first density region ranges from 0.35R to 0.65R, where R is the radius of the support structure.

[0014] Optionally, the support structure is a double-layer structure, with the upper and lower support structures both equipped with the plurality of microphones, and the interval between the upper and lower support structures is between 5mm and 50mm.

[0015] Optionally, it also includes a wind noise suppression structure, which is disposed on the support structure near the second edge, and the wind noise suppression structure includes at least one of a windbreak ring, a sound-absorbing ring, and a damping ring.

[0016] Optionally, it further includes a first back plate and a second back plate, wherein the first back plate is a rigid reflective back plate and is spaced apart from the support structure, the second back plate includes a damping material layer and a sound-absorbing material layer and is attached to the support structure, and the first back plate and the second back plate are switchable back plates.

[0017] Optionally, it also includes an expansion ring, wherein the second edge is disposed on the expansion ring, and an expansion microphone is disposed on the expansion ring.

[0018] Optionally, it also includes a calibration sound source, which is located on the side near the support structure where the plurality of microphones are located, or the calibration sound source is located on the side away from the support structure where the plurality of microphones are located.

[0019] Secondly, embodiments of this application provide an acoustic imaging system, including a synchronous sampling and clock distribution circuit, a processor, and a microphone assembly as described in the first aspect. The processor is electrically connected to the microphone assembly through the synchronous sampling and clock distribution circuit to acquire multi-channel synchronous data of the microphone assembly. The processor is used to output acoustic image data based on the multi-channel synchronous data.

[0020] Optionally, the processor includes a frequency band partitioning module, a subset selection module, a weighting module, and a generation module, wherein the frequency band partitioning module, the subset selection module, the weighting module, and the generation module are communicatively connected.

[0021] The frequency band division module is used to divide the multi-channel synchronization data of the microphone assembly into frequency bands to obtain multiple frequency band data, and the frequency band range of different frequency band data is different.

[0022] The subset selection module is used to determine, among the multiple microphones of the microphone assembly, a set of target microphones corresponding to the target frequency band data, wherein the target frequency band data is any one of the multiple frequency band data.

[0023] The weighting module is used to apply a target weighting coefficient to the data collected by each microphone in the target microphone set to obtain weighted data. The target weighting coefficient is a weighting coefficient determined in a pre-built weight library based on the position of the target microphone set on the support structure.

[0024] The generation module is used to perform beam generation on the weighted data and output acoustic image data.

[0025] Thirdly, embodiments of this application provide an acoustic imaging method applied to the acoustic imaging system described in the second aspect, the method comprising:

[0026] Acquire multi-channel synchronized data;

[0027] The multi-channel synchronization data is divided into frequency bands to obtain multiple frequency band data, and the frequency band range of different frequency band data is different;

[0028] Determine a target microphone set corresponding to the target frequency band data from the plurality of microphones, wherein the target frequency band data is any one of the plurality of frequency band data;

[0029] Apply target weighting coefficients to the data collected by each microphone in the target microphone set to obtain weighted data. The target weighting coefficients are weighting coefficients determined in a pre-built weight library based on the position of the target microphone set on the support structure.

[0030] Beamforming is performed on the weighted data to output acoustic image data.

[0031] In this embodiment, multiple microphones are arranged radially within an annular region between the first and second edges, with a denser central distribution and a sparser peripheral distribution. The high-density distribution at the center meets the sampling requirements of short-wavelength signals in the high-frequency band, effectively suppressing high-frequency spatial aliasing, grating lobes, and strong sidelobes, reducing imaging false hotspots, and improving the accuracy of high-frequency sound source localization. The low-density distribution at the outer edges maximizes the effective physical aperture of the microphone array without increasing the component volume or the total number of microphones, enhancing the angular resolution capability in the mid-to-low frequency band and reducing mid-to-low frequency positioning ambiguity. This effectively improves the performance of the microphone assembly. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is one of the structural schematic diagrams of a microphone assembly provided in the embodiments of this application;

[0034] Figure 2 This is a second schematic diagram of the structure of a microphone assembly provided in an embodiment of this application;

[0035] Figure 3 This is the third schematic diagram of a microphone assembly provided in the embodiments of this application;

[0036] Figure 4 This is the fourth schematic diagram of a microphone assembly provided in the embodiments of this application;

[0037] Figure 5 This is the fifth schematic diagram of a microphone assembly provided in the embodiments of this application;

[0038] Figure 6 This is a schematic diagram of the structure of an acoustic imaging system provided in an embodiment of this application;

[0039] Figure 7 This is a schematic diagram illustrating the selection of different microphone sets for different frequency bands provided in the embodiments of this application;

[0040] Figure 8 This is a flowchart illustrating the operation of an acoustic imaging system provided in an embodiment of this application.

[0041] Figure 9 This is a flowchart of an acoustic imaging method provided in an embodiment of this application. Detailed Implementation

[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] like Figure 1 As shown, this application embodiment provides a microphone assembly, including a support structure 10 and a plurality of microphones 20 disposed on the support structure 10. The support structure 10 has an opening 30 at its center. The plurality of microphones 20 are located in an annular region between the first edge 301 of the opening 30 and the second edge 101 of the support structure 10. The greater the distance between the microphone and the opening 30, the smaller the microphone distribution density.

[0044] In this embodiment, the support structure 10 can be circular or nearly circular, with a diameter ranging from 150mm to 550mm. An opening 30 is provided at the center of the support structure 10, with a diameter ranging from 20mm to 120mm. For example, the support structure 10 can be an annular structure, with an inner diameter (i.e., the diameter of the opening 30) of 50mm and an outer diameter of 340mm. The opening 30 at the center of the support structure 10 facilitates the placement of camera modules, ranging modules, or structural connectors at the opening 30 location. Furthermore, the opening 30 location is a no-display zone, meaning no microphone is placed there, reducing obstruction and assembly conflicts between the microphone and components such as the camera and ranging module, improving component integration, and ultimately achieving a comprehensive improvement in the imaging accuracy, robustness, and practicality of the microphone component within the constraints of portable size.

[0045] The microphones can be micro-electro-mechanical systems (MEMS) microphones, and the number of microphones mounted on the support structure 10 is greater than or equal to 128. For example, 256 microphones are arranged in the annular area between the first edge 301 and the second edge 101. In addition, an acoustically transparent mesh or a perforated protective layer can be provided on the microphones 20 to resist dust, moisture, impacts, and foreign object impacts in the industrial environment, thereby improving the environmental adaptability and structural durability of the components.

[0046] Multiple microphones 20 are arranged in an annular region between the first edge 301 and the second edge 101, resulting in a radial distribution of microphones that are densely packed in the center and sparsely packed at the periphery. That is, the greater the distance from the microphone to the opening 30, the lower the microphone density. The microphone density is high near the center of the support structure 10 to meet the spatial sampling requirements of high-frequency, short-wavelength arrays, suppress high-frequency spatial aliasing, grating lobes, and strong sidelobes, reduce false hotspots, and improve high-frequency positioning reliability. Conversely, the microphone density is low near the outer edge of the support structure 10, reducing channel redundancy caused by an overly dense array while preserving the effective physical aperture of the microphone array, thus reducing data volume, computational load, and power consumption.

[0047] In this way, multiple microphones 20 are arranged in a radial pattern within the annular region between the first edge 301 and the second edge 101, with a denser central distribution and a sparser outer distribution. The high-density distribution at the center meets the sampling requirements of short-wavelength signals in the high-frequency band, effectively suppressing high-frequency spatial aliasing, grating lobes, and strong sidelobes, reducing imaging false hotspots, and improving the accuracy of high-frequency sound source localization. The low-density distribution at the outer edges maximizes the effective physical aperture of the microphone array without increasing the component volume or the total number of microphones, enhancing the angular resolution capability in the mid-to-low frequency band and reducing mid-to-low frequency positioning ambiguity. This effectively improves the performance of the microphone component.

[0048] Optionally, the multiple microphones 20 are arranged in a non-periodic spiral radial pattern.

[0049] In this embodiment, as Figure 2 As shown, multiple microphones 20 are arranged in a non-periodic spiral radial pattern, breaking the periodic structural characteristics of regular arrays. This effectively reduces the probability of generating grating lobes and strong side lobes, suppressing artifacts and false hotspots caused by array periodicity, sparse sampling, and environmental reflections from the source, significantly improving the accuracy and reliability of sound source localization. At the same time, the non-periodic spiral distribution, combined with the density gradient design of dense central distribution and sparse peripheral distribution, ensures high-density sampling in the central region to meet the spatial sampling requirements of short-wavelength signals in the high-frequency band, effectively suppressing high-frequency aliasing and artifacts. Furthermore, the non-uniform arrangement of the peripheral spiral extension maximizes the expansion of the effective physical aperture, enhancing the angular discrimination capability in the mid-to-low frequency band, reducing the limitation of angular resolution in the low-frequency band for portable acoustic imaging devices, and improving the performance of the microphone assembly.

[0050] Furthermore, the non-periodic spiral structure can achieve flexible placement while meeting manufacturing and assembly constraints such as minimum spacing and no-distribution zones, taking into account both the manufacturability of the array and compatibility with on-site assembly. The sparse spiral arrangement on the periphery reduces the number of redundant microphones, lowers the computational load and system power consumption of signal acquisition and processing, and adapts to the computing power and size constraints of portable devices, ultimately improving the accuracy of acoustic imaging within the limitations of portable size.

[0051] To achieve a non-periodic spiral radial distribution of multiple microphones 20, please refer to the following description:

[0052] In some embodiments, in a polar coordinate system formed with the center of the support structure 10 as the pole, the polar coordinates of the first microphone disposed on the support structure 10 are (r i θ i The first microphone is the i-th microphone among the plurality of microphones;

[0053] in, 'a' is a scaling factor used to control the overall density and array expansion speed, and 'i' is the sequential number of the first microphone; θ i =θ0+iγ, where θ0 is the initial angle, γ is the angle increment that is not a rational multiple of π, and i is a positive integer from 1 to N, where N is the number of microphones.

[0054] In this embodiment, with the center of the supporting structure 10 as the pole, the installation position of all microphones 20 is defined by polar coordinates. For example, the polar coordinate of the i-th microphone (i.e., any one of the multiple microphones 20) is defined as (r i θ i ), where r i θ represents the radial distance from the i-th microphone to the center of the circle (i.e., the center of aperture 30). i This represents the angle of the microphone relative to the initial direction. To arrange the multiple microphones radially, r... i Defined as , The changing pattern of θ causes the microphone to gradually expand outward from the center, preventing the radius from growing too rapidly. Combined with the adjustment of the scaling factor 'a' (for example, a larger 'a' results in a sparser array and faster outward expansion, while a smaller 'a' results in a denser array and slower outward expansion), this allows for flexible matching of the support structure size and the total number of microphones. Simultaneously, it ensures high sampling density in the central region and low density in the outer region, adapting to high and low frequency sampling requirements. Furthermore, θ... i Defined as θ i =θ0+iγ, where γ is a non-π rational multiple to avoid periodic arrangement and thus prevent obvious periodicity in the array. Selecting a non-π rational multiple of γ (preferably a value close to the golden angle) ensures that the microphone angle distribution is non-periodic, reducing artifact interference from the topological structure and ensuring positioning reliability.

[0055] In this way, the microphone mounting coordinates are generated using an aperiodic spiral, achieving a radial distribution with dense microphones at the center and sparse microphones at the periphery. The aperiodicity of the arrangement is ensured by setting the angle increment, which meets the requirements of the aperiodic spiral radial layout, thereby improving the performance of the microphone assembly.

[0056] In some embodiments, in a polar coordinate system with the center of the supporting structure as the pole, the polar coordinates of the first microphone disposed on the supporting structure are (r i θ i The first microphone is the i-th microphone among the plurality of microphones;

[0057] in, , 'a' is the scaling factor, used to control the overall density and array expansion speed; 'i' is the sequential number of the first microphone; 'W(·)' is the monotonic radial mapping function; θ i =θ0+iγ, where θ0 is the initial angle and γ is the angle increment that is a non-π rational multiple.

[0058] In this embodiment, to make the multiple microphones arranged radially, r can also be... i Defined as , The changing pattern of the microphone allows it to gradually expand outward from the center, preventing excessively rapid radius growth. Combined with the adjustment of the scale coefficient 'a', the radial position of the microphone can be made to gradually expand outward with the numbering, naturally forming a basic distribution trend of denser center and sparser periphery. Furthermore, a monotonic radial mapping function W(·) is introduced, such as a piecewise linear function, power function, exponential compression / stretching function, or spline function, so that the radius near the center is compressed to increase the sampling density in the core area, and the radius near the outer edge is stretched to reduce the density in the outer edge area. This further enhances the zoning effect of high density in the core area and low density in the outer edge area, accurately matching the different needs of high-frequency sampling and low-frequency large aperture. In addition, θ is also... i Defined as θ i =θ0+iγ, where γ takes a value that is not a rational multiple of π, so that the microphone angle distribution is irregular and periodic, forming a non-periodic spiral arrangement. This eliminates the grating lobes, side lobes and false hot spots that are easy to be generated by regular arrays from the array topology, and improves the reliability of sound source localization.

[0059] Given that the polar coordinates of any microphone are (r i θ i After that, (r) i θ i The coordinates are converted into planar coordinates and mapped onto the support structure 10, so that each microphone is distributed in a non-periodic spiral radial pattern.

[0060] Furthermore, to meet the manufacturing, assembly, and acoustic imaging performance requirements of the microphone array, minimum spacing constraints, no-go zone constraints, and performance constraints can be applied to the initial microphone placement coordinates. For example, the minimum spacing constraint may include: ensuring that the distance between any two microphones is not less than S. min For example, S minThe thickness can range from 3mm to 10mm, depending on the encapsulation and mesh structure. Keep-out area constraints may include: microphones must not be placed in areas such as 30mm openings, mounting holes, cable routing corridors, support pillar locations, and shielding structures. Performance constraints may include: controlling sidelobe parameters across multiple frequency bands and multiple pointing angle domains, such as maximum sidelobe level or its proxy parameters.

[0061] Thus, at the structural level, the regular periodicity of the array is weakened by non-periodic spiral placement, variable density partitioning, and various constraint adjustments, thereby reducing the generation of grating lobes and strong sidelobes at the source. At the algorithmic level, the maximum sidelobe level in the target angular domain can be further reduced through the selection of frequency band-related subarrays, windowing or weighted coefficient design, and offline optimization. Among these, offline optimization uses sidelobe indices in multiple frequency bands and multiple pointing angular domains as objective functions or constraints. Finally, the microphone installation position is determined to meet the needs of mass production, balancing array manufacturability and acoustic imaging positioning reliability.

[0062] Optionally, from the first edge 301 to the second edge 101, the support structure 10 includes a first density region and a second density region, wherein the microphone density in the first density region is greater than the microphone density in the second density region.

[0063] The radius R of the first density region c The range is from 0.35R to 0.65R, where R is the radius of the supporting structure 10.

[0064] In this embodiment, as Figure 2 As shown, the array of multiple microphones is divided into a core region (i.e., the first density region) and an outer region (i.e., the second density region) from the first edge 301 to the second edge 101. The radius R of the core region is... c The range can be from 0.35R to 0.65R, for example, R c A radius of 0.45R can be selected to meet the spatial sampling requirements of high-frequency signals and effectively suppress spatial aliasing, grating lobe, and side lobe artifacts. The effective aperture of the microphone array is expanded by setting the outer edge region without increasing the array volume, which improves the angular resolution capability of the mid-to-low frequency sound source. At the same time, the radial range division takes into account the manufacturability of array layout and the balance between high and low frequency imaging performance, further optimizing the positioning accuracy and imaging robustness of portable acoustic imaging equipment.

[0065] Optionally, the support structure 10 is a double-layer structure, with multiple microphones 20 provided in both the upper and lower support structures, and the interval between the upper and lower support structures is between 5mm and 50mm.

[0066] In this embodiment, the support structure 10 adopts a double-layered structure with upper and lower layers, and multiple microphones 20 are arranged in both the upper and lower layers with the interlayer spacing controlled between 5mm and 50mm. This can form a three-dimensional layered array without significantly increasing the lateral size, effectively expanding the three-dimensional spatial sampling dimension and equivalent aperture, and further improving the angular resolution and sound source pointing accuracy in the mid-low frequency band. In addition, the collaborative sampling of the double-layered microphones can also improve signal redundancy and anti-interference ability, and optimize the imaging stability in complex industrial scenarios.

[0067] Optionally, it also includes a wind noise suppression structure 40, which is disposed on the support structure 10 near the second edge 101. The wind noise suppression structure 40 includes at least one of a wind deflector ring 401, a sound-absorbing ring 402, and a damping ring 403.

[0068] In this embodiment, as Figure 3 As shown, a wind noise suppression structure 40 is set at the position of the support structure 10 near the second edge 101 to reduce airflow noise interference in complex industrial sites, reduce wind noise pollution of multi-channel microphone acquisition signals, and improve the anti-interference capability and signal robustness of the acoustic imaging system in harsh environments. At the same time, the wind noise suppression structure 40 is arranged on the outer edge of the microphone array, which can achieve wind noise suppression while avoiding obstruction and interference to normal sound field acquisition, ensuring sound source positioning accuracy, and adapting to the stable working requirements of portable acoustic imaging equipment in multi-scenario industrial inspection.

[0069] Optionally, it also includes a first back plate 50 and a second back plate 60. The first back plate 50 is a rigid reflective back plate and is spaced apart from the support structure 10. The second back plate 60 includes a damping material layer 601 and a sound-absorbing material layer 602 and is attached to the support structure 10. The first back plate 50 and the second back plate 60 are switchable back plates.

[0070] In this embodiment, as Figure 4 As shown, the first backplate 50 is a rigid reflective backplate and is spaced apart from the support structure 10 to enhance the far-field directivity of the array and improve the ability to locate distant sound sources; the second backplate 60 includes a damping material layer 601 and a sound-absorbing material layer 602 and is attached to the support structure 10, which can effectively suppress structural reflection, vibration coupling and artifact interference.

[0071] With the switchable configuration of two backplates, the operating state can be flexibly selected according to different industrial environments, target frequency bands, and imaging requirements. This allows the acoustic imaging equipment to achieve optimal adaptation between far-field directivity and artifact suppression, improving imaging robustness and scene adaptability under complex working conditions. For example, when detecting far-field sound sources such as gas leaks or electrical discharges at a distance and when the ambient reflection is weak, the first rigid reflective backplate is switched on to enhance the array's far-field directivity and improve the sensitivity and angular resolution of far-field sound source localization. When detecting near-field sound sources or when there is strong structural reflection or equipment vibration interference in the field, the second backplate, which is fitted to the support structure, is switched on. Through the damping material layer and sound-absorbing material layer, structural reflection and vibration coupling are weakened, suppressing imaging artifacts and false hot spots, thereby flexibly adapting to different imaging requirements according to actual working conditions.

[0072] Optionally, it also includes an expansion ring, wherein the second edge is disposed on the expansion ring, and an expansion microphone is disposed on the expansion ring.

[0073] In this embodiment, by setting up an expansion ring and an expansion microphone, the overall effective aperture of the array can be effectively expanded without changing the original layout of the microphone array, further improving the angular resolution capability of mid-to-low frequency sound sources. Furthermore, the expansion ring can be detachably connected to the second edge of the support structure 10, allowing for flexible assembly and disassembly according to actual testing needs. This facilitates product serialization and multi-specification adaptation, while not affecting the high-frequency imaging performance and structural stability of the original array, thus balancing improved acoustic imaging performance with product scalability.

[0074] Optionally, it also includes a calibration sound source 70, which is located on the side near the support structure 10 where there are multiple microphones, or the calibration sound source 70 is located on the side away from the support structure 10 where there are multiple microphones.

[0075] In this embodiment, as Figure 5As shown, the calibration sound source 70 is positioned on the side near the support structure 10 where multiple microphones are located. By configuring the calibration sound source 70, known excitation signals such as sweep frequency, chirp, or narrowband can be output, providing a standard reference input for self-calibration. The acoustic imaging system can trigger a self-calibration process upon power-on or periodic maintenance: first, the calibration sound source 70 is driven to emit a preset excitation signal, and each microphone channel synchronously acquires the response data of this excitation; then, the acquired data is analyzed to estimate the gain, phase, and time delay errors of each channel, generating or updating correction parameters and writing them into the calibration table for subsequent imaging to compensate for channel errors. Simultaneously, abnormal faulty channels such as those with missing responses, abnormal noise, or phase jumps are identified and removed from the effective aperture selection during subsequent imaging processing. This effectively compensates for channel consistency degradation caused by assembly tolerances, temperature drift, and other factors, avoiding interference from faulty channels on the imaging results, thereby improving the measurement accuracy, long-term operational stability, and reliability of the acoustic imaging system in complex industrial environments.

[0076] It should be understood that when the calibration sound source 70 is set on the side opposite to the support structure 10 where the multiple microphones are located, the same technical effect can be achieved. To avoid repetition, it will not be described again here.

[0077] This application also provides an acoustic imaging system, such as... Figure 6 As shown, it includes a synchronous sampling and clock distribution circuit, a processor, and the aforementioned microphone assembly. The processor is electrically connected to the microphone assembly through the synchronous sampling and clock distribution circuit to acquire multi-channel synchronous data of the microphone assembly. The processor is used to output acoustic image data based on the multi-channel synchronous data.

[0078] In this embodiment, the processor is electrically connected to the microphone assembly via a synchronous sampling and clock distribution circuit to achieve synchronous acquisition and reliable transmission of multi-channel microphone signals. This allows the processor to obtain multi-channel synchronous data output by the microphone assembly. Based on this multi-channel synchronous data, the processor performs beamforming, frequency band adaptive processing, and other calculations, ultimately outputting high-quality acoustic image data. Because the microphones in the microphone assembly are distributed with high density at the center and low density at the outer edges, sufficient spatial sampling density can be ensured in the high-frequency band to suppress spatial aliasing, grating lobe, and side lobe artifacts. In the mid-to-low frequency band, a larger effective aperture improves the sound source angular resolution. Simultaneously, the non-uniform arrangement weakens the array periodicity to reduce false hotspots, thereby improving the accuracy of acoustic imaging in the acoustic imaging system.

[0079] Optionally, the processor includes a frequency band partitioning module, a subset selection module, a weighting module, and a generation module, wherein the frequency band partitioning module, the subset selection module, the weighting module, and the generation module are communicatively connected.

[0080] The frequency band division module is used to divide the multi-channel synchronization data of the microphone assembly into frequency bands to obtain multiple frequency band data, and the frequency band range of different frequency band data is different.

[0081] The subset selection module is used to determine, among the multiple microphones of the microphone assembly, a set of target microphones corresponding to the target frequency band data, wherein the target frequency band data is any one of the multiple frequency band data.

[0082] The weighting module is used to apply a target weighting coefficient to the data collected by each microphone in the target microphone set to obtain weighted data. The target weighting coefficient is a weighting coefficient determined in a pre-built weight library based on the position of the target microphone set on the support structure.

[0083] The generation module is used to perform beam generation on the weighted data and output acoustic image data.

[0084] In this embodiment, the frequency band division module performs precise frequency band division on the multi-channel synchronization data of the microphone component, obtaining multiple sets of frequency band data covering different frequency ranges. For example, the signal can be divided into multiple frequency bands through Fast Fourier Transform (FFT), Short-time Fourier Transform (STFT), or filter banks, providing a data basis for differentiated processing. For example, frequency band division yields frequency band A (0.5kHz~8kHz), frequency band B (8kHz~20kHz), and frequency band C (20kHz~100kHz).

[0085] The subset selection module selects a corresponding set of target microphones from the microphone components for any target frequency band data. For example, for frequency band A, it selects a full array of microphones including both the core and outer regions to form a large effective aperture and improve mid-to-low frequency angular resolution; for frequency band B, it selects microphones with a sparse subset of the core and outer regions, balancing aperture size and aliasing suppression; for frequency band C, it selects microphones primarily composed of high-density microphones in the core region, retaining only a small number of microphones in the outer region that meet spacing and pattern constraints, to suppress high-frequency spatial aliasing and artifacts. Figure 7 As shown.

[0086] The weighting module matches target weighting coefficients from a pre-built weight library based on the position of the target microphone array on the support structure and applies them to the data acquired by each microphone. This effectively compensates for consistency errors caused by channel tolerances and temperature drift, while optimizing the beam pattern to suppress sidelobes and aliasing artifacts. Specifically, for higher frequency bands, a subset of the core region is preferentially used with robust weights to improve noise immunity. For example, weighting coefficients adapted to a large aperture are applied to the full array microphones corresponding to frequency band A to compensate for channel phase and gain deviations; weighting coefficients emphasizing sidelobe suppression are applied to the microphone array primarily located in the core region corresponding to frequency band C to reduce high-frequency pseudo-hotspots and grating lobe interference.

[0087] The generation module performs beamforming operations on the weighted data, ultimately outputting high-quality acoustic image data. For example, using beamforming algorithms such as frequency domain beamforming and time delay summation, the weighted data for each frequency band is processed separately to generate single-band acoustic images. Then, the multi-band imaging results are fused to output final acoustic image data with both high and low frequency sound source localization accuracy.

[0088] In this way, by selecting microphones at different positions for different frequency bands to form effective apertures, it is possible to adapt to the different needs of large apertures in the mid-to-low frequency band to improve angular resolution, and high-density sampling in the high frequency band to suppress spatial aliasing and sidelobe artifacts. This achieves optimal matching of sound source localization performance in each frequency band, thereby improving the accuracy of acoustic imaging in the acoustic imaging system.

[0089] like Figure 8 As shown in the embodiments of this application, an acoustic imaging system can realize full-bandwidth acquisition, frequency-band differentiated processing, and imaging output, specifically including the following stages:

[0090] Input data stage: Receives multi-channel synchronous raw audio data collected by the microphone assembly, providing a complete acoustic signal foundation for subsequent processing.

[0091] Frequency band division stage: Multi-channel synchronous data can be decomposed into frequency domains using methods such as FFT, filter banks, or STFT, and split into multiple frequency bands (such as low frequency A, medium frequency B, and high frequency C), realizing the frequency band decomposition of the full bandwidth signal and providing data prerequisites for differentiated processing.

[0092] Subset selection stage: For each frequency band, the corresponding microphone subset is selected based on the characteristics of the frequency band: for the low frequency band, the full array of the core area plus the outer edge area is selected to expand the effective aperture; for the mid frequency band, the sparse subset of the core area plus the outer edge area is selected to balance the aperture and aliasing; for the high frequency band, the high-density subset of the core area is the main component, and only a small number of compliant outer edge array elements are selected to achieve the differentiated construction of the exclusive effective aperture of each frequency band.

[0093] Frequency band related weighting stage: For the selected microphone subset, the target weighting coefficient (or windowed weight) is matched from the preset weight library according to its position on the support structure. This not only compensates for the consistency error caused by channel tolerance and temperature drift, but also optimizes the beam pattern to suppress artifacts such as sidelobes and aliasing.

[0094] Beamforming stage: Beamforming algorithms (such as time delay summation, frequency domain beamforming, etc.) are executed on the weighted data after weighting to complete the acoustic imaging data calculation for single or multi-band frequencies.

[0095] The final output stage of acoustic image output is a single-band acoustic image or a high-quality acoustic image after multi-band fusion, which enables accurate localization and visualization of the sound source.

[0096] This application provides an acoustic imaging method applied to the aforementioned acoustic imaging system, such as... Figure 9 As shown, the method includes:

[0097] Acquire multi-channel synchronized data;

[0098] The multi-channel synchronization data is divided into frequency bands to obtain multiple frequency band data, and the frequency band range of different frequency band data is different;

[0099] Determine a target microphone set corresponding to the target frequency band data from the plurality of microphones, wherein the target frequency band data is any one of the plurality of frequency band data;

[0100] Apply target weighting coefficients to the data collected by each microphone in the target microphone set to obtain weighted data. The target weighting coefficients are weighting coefficients determined in a pre-built weight library based on the position of the target microphone set on the support structure.

[0101] Beamforming is performed on the weighted data to output acoustic image data.

[0102] In this embodiment, by acquiring multi-channel synchronous data, dividing frequency band data based on different frequency band ranges, matching corresponding microphone sets for the target frequency band, selecting weighting coefficients from a preset weight library based on microphone positions and applying weighting processing, and then performing beam generation on the weighted data, it can fully adapt to the non-periodic spiral layout characteristics of the microphone component with high density at the center and low density at the periphery, and realize frequency band adaptive differentiated imaging processing.

[0103] Specifically, for the low and mid-frequency bands, the angular resolution is improved by matching the full array, and for the high-frequency bands, spatial aliasing and artifacts are suppressed by using a high-density microphone array in the core area. At the same time, the position-correlated weighting coefficients are used to effectively compensate for consistency errors such as channel tolerance and temperature drift, and optimize the beam pattern, thereby improving the sound source localization accuracy, imaging robustness and scene adaptability of the acoustic imaging system, and achieving high-quality and high-reliability acoustic image output.

[0104] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0105] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0106] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A microphone assembly, characterized in that, The device includes a support structure and a plurality of microphones disposed on the support structure. The support structure has an opening at its center. The plurality of microphones are located in an annular region between a first edge of the opening and a second edge of the support structure. The greater the distance between the microphones and the opening, the lower the microphone distribution density.

2. The microphone assembly according to claim 1, characterized in that, The multiple microphones are arranged in a non-periodic spiral radial pattern.

3. The microphone assembly according to claim 2, characterized in that, In a polar coordinate system with the center of the supporting structure as the pole, the polar coordinates of the first microphone mounted on the supporting structure are (r i θ i The first microphone is the i-th microphone among the plurality of microphones; in, 'a' is a scaling factor used to control the overall density and array expansion speed, and 'i' is the sequential number of the first microphone; θ i =θ0+iγ, where θ0 is the initial angle and γ is the angle increment that is a non-π rational multiple.

4. The microphone assembly according to claim 2, characterized in that, In a polar coordinate system with the center of the supporting structure as the pole, the polar coordinates of the first microphone mounted on the supporting structure are (r i θ i The first microphone is the i-th microphone among the plurality of microphones; in, , 'a' is the scaling factor, used to control the overall density and array expansion speed; 'i' is the sequential number of the first microphone; 'W(·)' is the monotonic radial mapping function; θ i =θ0+iγ, where θ0 is the initial angle and γ is the angle increment that is a non-π rational multiple.

5. The microphone assembly according to claim 1, characterized in that, From the first edge to the second edge, the support structure includes a first density region and a second density region, wherein the microphone density in the first density region is greater than the microphone density in the second density region; The first density region ranges from 0.35R to 0.65R, where R is the radius of the support structure.

6. The microphone assembly according to any one of claims 1 to 5, characterized in that, The support structure is a double-layer structure, with the upper and lower support structures both equipped with the multiple microphones, and the interval between the upper and lower support structures is between 5mm and 50mm.

7. The microphone assembly according to any one of claims 1 to 5, characterized in that, It also includes a wind noise suppression structure, which is disposed on the support structure near the second edge, and the wind noise suppression structure includes at least one of a windbreak ring, a sound-absorbing ring, and a damping ring.

8. The microphone assembly according to any one of claims 1 to 5, characterized in that, It also includes a first back plate and a second back plate. The first back plate is a rigid reflective back plate and is spaced apart from the support structure. The second back plate includes a damping material layer and a sound-absorbing material layer and is attached to the support structure. The first back plate and the second back plate are switchable.

9. The microphone assembly according to any one of claims 1 to 5, characterized in that, It also includes an expansion ring, which has the second edge and an expansion microphone.

10. The microphone assembly according to any one of claims 1 to 5, characterized in that, It also includes a calibration sound source, which is located on the side near the support structure where the plurality of microphones are located, or the calibration sound source is located on the side away from the support structure where the plurality of microphones are located.

11. An acoustic imaging system, characterized in that, The device includes a synchronous sampling and clock distribution circuit, a processor, and a microphone assembly as described in any one of claims 1 to 10. The processor is electrically connected to the microphone assembly via the synchronous sampling and clock distribution circuit to acquire multi-channel synchronous data of the microphone assembly. The processor is used to output acoustic image data based on the multi-channel synchronous data.

12. The acoustic imaging system according to claim 11, characterized in that, The processor includes a frequency band partitioning module, a subset selection module, a weighting module, and a generation module, wherein the frequency band partitioning module, the subset selection module, the weighting module, and the generation module are communicatively connected. The frequency band division module is used to divide the multi-channel synchronization data of the microphone assembly into frequency bands to obtain multiple frequency band data, and the frequency band range of different frequency band data is different. The subset selection module is used to determine, among the multiple microphones of the microphone assembly, a set of target microphones corresponding to the target frequency band data, wherein the target frequency band data is any one of the multiple frequency band data. The weighting module is used to apply a target weighting coefficient to the data collected by each microphone in the target microphone set to obtain weighted data. The target weighting coefficient is a weighting coefficient determined in a pre-built weight library based on the position of the target microphone set on the support structure. The generation module is used to perform beam generation on the weighted data and output acoustic image data.

13. An acoustic imaging method, characterized in that, Applied to the acoustic imaging system as described in any one of claims 11 or 12, characterized in that the method comprises: Acquire multi-channel synchronized data; The multi-channel synchronization data is divided into frequency bands to obtain multiple frequency band data, and the frequency band range of different frequency band data is different; Determine a target microphone set corresponding to the target frequency band data from the plurality of microphones, wherein the target frequency band data is any one of the plurality of frequency band data; Apply target weighting coefficients to the data collected by each microphone in the target microphone set to obtain weighted data. The target weighting coefficients are weighting coefficients determined in a pre-built weight library based on the position of the target microphone set on the support structure. Beamforming is performed on the weighted data to output acoustic image data.

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