A beamforming system and method for wideband signal reception

Abstract

This invention relates to a beamforming system and method for broadband signal reception. The system includes: a reconfigurable circular microphone array, composed of several microphone units, for acquiring multi-channel acoustic signals with different radius configurations; a motion control module connected to the reconfigurable circular microphone array, for adaptively controlling the radius variation of the reconfigurable circular microphone array according to the frequency of the target signal; and a signal processing module for receiving the multi-channel signals acquired by the reconfigurable circular microphone array, applying a beamforming algorithm to generate corresponding intermediate spatial spectra for each radius configuration, fusing multiple intermediate spatial spectra to generate a combined spatial spectrum with suppressed grating lobes, and outputting a direction estimate of the sound source based on the combined spatial spectrum. Compared with the prior art, this invention has the advantages of achieving high spatial resolution and low grating lobe beamforming for broadband signals.

Description

Technical Field

[0001] This invention relates to the fields of acoustic signal processing, virtual reality and augmented reality, and in particular to a beamforming system and method for broadband signal reception. Background Technology

[0002] In various technological fields such as audio signal processing, virtual reality (VR), augmented reality (AR), intelligent voice interaction, sonar detection, radar communication, and security monitoring, direction of arrival (DoA) estimation of sound waves is a core and crucial technology. Specifically, DoA refers to the spatial angular parameter of a sound wave relative to a preset reference coordinate system of a microphone array when it reaches the array's reference point during propagation. It is typically composed of azimuth and elevation angles. The azimuth angle characterizes the offset angle of the sound wave in the horizontal plane relative to a reference direction (such as the array's central axis), while the elevation angle characterizes the offset angle of the sound wave in the vertical plane relative to a horizontal reference plane. The combination of these two angles allows for precise location of the sound source's specific propagation direction in three-dimensional space, providing a fundamental basis for subsequent signal enhancement, source separation, target tracking, and other processing.

[0003] In DoA estimation using microphone arrays, grating lobes are a common and critical issue affecting estimation accuracy. Grating lobes essentially form because the spacing between adjacent microphones in the array is greater than half the wavelength of the signal being processed (i.e., half the wavelength). This causes periodic spurious peaks in the array's spatial response. The amplitude of these spurious peaks is comparable to that of the main lobe, resulting in multiple indistinguishable peak signals in the spatial spectrum. This leads to ambiguity in DoA estimation, making it impossible to accurately determine the direction of the true sound source. In severe cases, it can even cause incorrect sound source localization, impacting the overall system performance.

[0004] With the rapid development of VR / AR technology, its application scenarios are constantly expanding, from consumer-grade VR games and AR navigation to industrial-grade virtual simulation and remote collaboration, and even virtual surgical guidance in the medical field. This places increasingly higher demands on auditory immersion and sound-based interactive experiences. In these applications, accurate estimation of the Angle of Arrival (AoA, consistent with the DoA concept, both referring to the angular parameter of the direction of sound wave arrival) is a core prerequisite for achieving high-fidelity spatial audio rendering and precise sound source localization interaction. Only by accurately acquiring the AoA information of each sound source in the environment can users be presented with a sense of sound location and distance consistent with the real scene, achieving an immersive experience of "sound localization." Simultaneously, it supports sound-based gesture control, sound source tracking, and other interactive functions, improving the practicality and naturalness of the VR / AR system.

[0005] Currently, in VR / AR and other applications requiring AoA estimation, traditional receiver beamforming methods are still widely used. These methods typically rely on microphone arrays with fixed geometries (such as linear arrays, circular arrays, square arrays, etc.). Through a preset array layout and beamforming algorithm, sound wave signals in a specific direction are enhanced while interference signals in other directions are suppressed, thereby achieving AoA estimation.

[0006] However, fixed arrays have inherent defects that are difficult to overcome. The core contradiction lies in the balance between spatial resolution and grating lobe suppression: on the one hand, in order to improve the spatial resolution of AoA estimation, the spacing between adjacent microphones in the microphone array needs to be increased. The larger the spacing, the stronger the array's ability to distinguish sound waves from different directions, and the higher the spatial resolution. On the other hand, when the microphone spacing exceeds half the wavelength of the signal to be processed, grating lobes will inevitably appear. Moreover, the larger the spacing, the stronger the intensity of the grating lobes, the more serious the ambiguity of AoA estimation, and even false localization may occur.

[0007] Crucially, in practical applications such as VR / AR, the acoustic signals that need to be processed are typically broadband signals (such as 20Hz-20kHz audio signals audible to the human ear). The half-wavelengths of signals at different frequencies differ significantly—low-frequency signals have longer wavelengths and correspondingly larger half-wavelengths, while high-frequency signals have shorter wavelengths and correspondingly smaller half-wavelengths. For microphone arrays with fixed spacing, it is impossible to simultaneously satisfy the half-wavelength condition for all frequency components in a broadband signal: if the microphone spacing is designed according to the half-wavelength of the low-frequency signal, although it can suppress grating lobes in low-frequency signals, for high-frequency signals, this spacing will be much larger than its half-wavelength, resulting in severe grating lobes in high-frequency signals and causing fuzzy AoA estimation in the high-frequency band; if the microphone spacing is designed according to the half-wavelength of the high-frequency signal, although it can ensure the positioning accuracy in the high-frequency band, for low-frequency signals, this spacing will be smaller than its half-wavelength, resulting in a significant decrease in spatial resolution in the low-frequency band, making it impossible to accurately distinguish sound sources from similar directions.

[0008] To address the shortcomings of fixed arrays, existing technologies have proposed several non-uniform array design schemes. By scrambling the microphone arrangement and adopting irregular array layouts, these schemes alleviate the conflict between grating lobes and spatial resolution to some extent, improving the performance of broadband signal processing. However, these non-uniform arrays still have significant limitations: once the array layout is designed, it cannot be dynamically adjusted according to the actual acoustic environment and the frequency characteristics of the signal being processed, lacking dynamic adaptability. In complex acoustic environments (such as those with multiple sound source interference, echoes, noise, or dynamic changes in signal frequency distribution), the performance of non-uniform arrays degrades significantly, making it difficult to maintain the consistency and accuracy of AoA estimation, and failing to meet the high-precision, high-stability sound source localization requirements of high-end applications such as VR / AR.

[0009] A search revealed Chinese invention patent application publication number CN111540371A, which discloses a method for microphone array beamforming. The method includes: a microphone array comprising M microphones uniformly distributed on the same circular ring, M = 2n, n = 2, 3, 4…, where the aperture c of the microphone array is the speed of sound and f is the highest frequency of the signal. The method includes: receiving an audio input signal and determining a target direction based on sound source localization, the target direction being an arbitrary angle; generating a specified beam in the target direction from the audio input signal using a specified calculation method, wherein the specified calculation method is derived from matrix C; generating a corrected beam corresponding to the specified beam within a specified angular range from the target direction; canceling the corrected beam with the specified beam using an adaptive filter to obtain a beam output in the target direction; and outputting the beam output in the target direction. The output signal beam of the small-aperture microphone array pointing in an arbitrary angular direction is obtained through matrix C. This existing patent application has the problem of failing to solve the problem of broadband signal grating lobes.

[0010] In applications such as VR / AR that require high accuracy in AoA estimation and environmental adaptability, designing a receiving beamforming scheme that balances high spatial resolution and low ambiguity while adapting to the reception requirements of broadband signals has become a technical problem that needs to be solved. Summary of the Invention

[0011] The purpose of this invention is to overcome the shortcomings of the prior art and provide a beamforming system and method for broadband signal reception.

[0012] The objective of this invention can be achieved through the following technical solutions: According to one aspect of the present invention, a beamforming system for broadband signal reception is provided, the system comprising: A reconfigurable circular microphone array, consisting of several microphone units, is used to collect multi-channel acoustic signals under different radius configurations; A motion control module connected to a reconfigurable circular microphone array is used to adaptively control the radius change of the reconfigurable circular microphone array according to the frequency of the target signal. The system also includes a signal processing module for receiving multi-channel signals acquired by the reconfigurable circular microphone array, applying a beamforming algorithm to generate corresponding intermediate spatial spectra for each radius, fusing multiple intermediate spatial spectra to generate a combined spatial spectrum with suppressed grating lobes, and outputting a direction estimate of the sound source based on the combined spatial spectrum.

[0013] As a preferred technical solution, the reconfigurable circular microphone array is a double-layer ring structure, comprising: A fixed inner ring frame is provided with several radially extending straight guide grooves; The outer ring frame is rotatable and has several arc-shaped guide grooves on it; The outer ring frame and the inner ring frame are coaxially arranged and can rotate relative to each other. The outer ring frame and the inner ring frame are connected by a coaxial rotary support structure, which is fitted and installed on the outer edge of the inner ring frame. Each of the microphone units is simultaneously constrained at the intersection of one of the straight guide slots and one of the arc-shaped guide slots; The coaxial rotatable connection structure is any one of the following: 1) Bearing rolling fit structure; 2) Sliding clearance fit structure.

[0014] As a preferred technical solution, the outer ring frame is coaxially connected to the inner ring frame through an independent support base.

[0015] As a preferred technical solution, the motion control module controls the rotation of the outer ring frame, and through the synergistic effect of the arc-shaped guide groove and the straight guide groove, drives the microphone unit to move radially along the straight guide groove, thereby changing the radius of the microphone array.

[0016] As a preferred technical solution, the trajectory of the arc-shaped guide groove satisfies a preset polar coordinate equation, so that the radial movement distance of the microphone unit is linearly related to the rotation angle of the outer ring frame.

[0017] As a preferred technical solution, the trajectory of the arc-shaped guide groove is an Archimedean spiral.

[0018] According to another aspect of the present invention, a beamforming method for broadband signal reception is provided, the method comprising: The motion control module controls the reconfigurable circular microphone array to acquire multi-channel acoustic signals in multiple different radius configurations; For each radius configuration, the signal processing module uses a beamforming algorithm to generate a corresponding intermediate spatial spectrum from the acoustic signals acquired; multiple intermediate spatial spectra are then fused to generate a combined spatial spectrum. The signal processing module detects the peak value of the combined spatial spectrum and uses the angle corresponding to the peak value as the direction of arrival of the sound source.

[0019] As a preferred technical solution, the control of the reconfigurable circular microphone array to acquire multi-channel acoustic signals under multiple different radius configurations includes: The motion control module controls the reconfigurable circular microphone array to acquire sound source signals at a first radius threshold, and performs time-frequency transformation on the acquisition results to determine the dominant frequency of the target signal; Based on the dominant frequency of the target signal, the motion control module gradually adjusts the radius of the reconfigurable circular microphone array from a first radius threshold to a second radius threshold, and acquires multi-channel acoustic signals under at least two different radius configurations.

[0020] As a preferred technical solution, the reconfigurable circular microphone array is a double-layer ring structure, comprising: A fixed inner ring frame is provided with several radially extending straight guide grooves; The outer ring frame is rotatable and has several arc-shaped guide grooves on it; The outer ring frame and the inner ring frame are coaxially arranged and can rotate relative to each other. The outer ring frame and the inner ring frame are connected by a coaxial rotary support structure, which is fitted and installed on the outer edge of the inner ring frame. The motion control module controls the rotation of the outer ring frame, and through the synergistic effect of the arc-shaped guide groove and the straight guide groove, drives the microphone unit to move radially along the straight guide groove, thereby changing the radius of the microphone array.

[0021] As a preferred technical solution, the beamforming algorithm includes the MUSIC algorithm, the ESPRIT algorithm, and a neural network algorithm based on deep learning.

[0022] Compared with the prior art, the present invention has the following beneficial effects: 1) The system of this invention overcomes the inherent limitation of traditional fixed microphone arrays, which cannot simultaneously satisfy the half-wavelength conditions of different frequency bands of broadband signals, through the coordinated operation of a reconfigurable circular microphone array, a motion control module, and a signal processing module. The motion control module can adaptively adjust the radius of the microphone array according to the target signal frequency, so that the spacing between array elements satisfies the grating lobe suppression condition in each frequency band; the signal processing module further eliminates grating lobe ambiguity under a single array configuration through multi-radius intermediate spatial spectrum fusion, achieving high spatial resolution and low ambiguity sound source direction estimation across the entire frequency band of broadband signals.

[0023] 2) The reconfigurable circular microphone array of this invention adopts a double-layer ring structure. The fixed inner ring frame and the rotatable outer ring frame are combined through a coaxial rotary support structure, providing a stable and reliable mechanical foundation for the dynamic adjustment of the array radius. The inner ring frame serves as a support reference to ensure structural stability, while the outer ring frame drives the microphone units to move through arc-shaped guide grooves. The microphone units are simultaneously constrained to the intersection of the straight guide groove and the arc-shaped guide groove. By controlling the rotation angle of the outer ring frame, all microphone units can be driven to move synchronously without individual control of each unit. This achieves synchronous and uniform radial movement of all microphone units when the outer ring frame rotates. This design ensures that the array maintains a uniform circular distribution after reconstruction, avoids array geometric distortion caused by asynchronous movement of microphone units, ensures the consistency of the array manifold under different radius configurations, provides a stable and predictable signal input for subsequent spatial spectrum fusion algorithms, and effectively improves the robustness and accuracy of sound source direction estimation.

[0024] 3) The trajectory of the arc-shaped guide groove pole of this invention satisfies the preset polar coordinate equation, making the radial movement distance of the microphone unit linearly related to the rotation angle of the outer ring frame, simplifying the control logic and calibration process of the motion control module. The motion control module can quickly calculate the rotation angle corresponding to the target radius through a simple linear conversion model, without the need for complex nonlinear compensation; at the same time, the linear relationship ensures the uniformity and predictability of the array radius adjustment process, avoids uneven array distribution caused by local movement anomalies, and improves the consistency of spatial resolution under different radius configurations. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the beamforming system in an embodiment of the present invention; Figure 2 This is a schematic diagram of the inner ring frame structure of the reconfigurable circular microphone array in an embodiment of the present invention; Figure 3 This is a schematic diagram of the outer ring structure of the reconfigurable circular microphone array in an embodiment of the present invention; Figure 4 This is a schematic diagram of the inner and outer ring frame combination of the reconfigurable circular microphone array in an embodiment of the present invention; Figure 5 This is a schematic diagram of a beamforming system in a VR / AR application according to an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the effect of suppressing grating lobes after fusion of intermediate spatial spectra at different radii in an embodiment of the present invention. Detailed Implementation

[0026] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0027] Example 1 This embodiment relates to a beamforming system for broadband signal reception, such as... Figure 1 The system includes: A reconfigurable circular microphone array, with its radius dynamically adjustable, overcomes the physical limitations of fixed arrays, providing a hardware foundation for wideband adaptation. The reconfigurable circular microphone array consists of N microphone units, where N≥2, used to acquire multi-channel acoustic signals.

[0028] Explanation of Array Shape Selection: The microphone array of this invention preferably adopts a uniform circular structure. The principle behind this is that a circular array is isotropic, meaning the array manifold remains consistent within a 360° azimuth range, and the main lobe width does not change with the direction of the sound source, thus providing consistent spatial resolution. Simultaneously, the circular structure naturally matches the mechanical design of the double-layer concentric ring frame, ensuring that all microphone units remain symmetrically distributed during radius adjustment, facilitating synchronous radial movement. In contrast, rectangular arrays exhibit significant resolution differences at 0° and 90°, linear arrays suffer from blurring around 180°, and while spiral arrays can suppress some grating lobes, their adjustment mechanisms are complex; therefore, none of these are considered preferred embodiments of this invention.

[0029] A motion control module is connected to the reconfigurable circular microphone array. This module controls the radius of the reconfigurable circular microphone array to continuously or discretely vary between a first radius threshold and a second radius threshold, based on the frequency of the target signal. This module achieves adaptive matching between the frequency and the microphone array radius, suppressing grating lobes from the hardware level. Specifically, the radius adjustment method is as follows: calculate the desired radius based on the target frequency f0. Where N is the number of elements in the microphone array, and c is the speed of sound in air. The radius is π. For example, when N=8 and f0=15kHz, λ≈2.29cm, half wavelength≈1.15cm, but to avoid physical interference with the microphone, the actual minimum radius is set to 2cm, so the system adjusts the radius to 2cm (i.e., the lower limit). If f0=5kHz, λ≈6.86cm, half wavelength≈3.43cm, then the radius is adjusted to about 3.5cm to obtain the best resolution. The motion control system drives the servo motor according to this target radius value, changing the radius of the reconfigurable circular microphone array from the current value to the target radius value. A signal processing module receives multi-channel acoustic signals collected by the microphone array under different radius configurations, applies a beamforming algorithm to generate the corresponding intermediate spatial spectrum for each radius configuration, and fuses multiple intermediate spatial spectra to suppress grating lobes, generating a combined spatial spectrum. Finally, the direction of attack (AOA) of the sound source is estimated based on the combined spatial spectrum.

[0030] Furthermore, the reconfigurable circular microphone array includes: 1) A fixed inner ring frame 1, on which several radially extending straight guide grooves 11 are provided, such as... Figure 2 ; 2) A rotatable outer ring frame 2, on which several arc-shaped guide grooves 21 are provided, such as Figure 3 The trajectory of the arc-shaped guide groove satisfies the preset polar coordinate equation, making the radial movement distance of the microphone unit linearly related to the rotation angle of the outer ring frame; 3) N microphone units 3, each microphone unit is simultaneously constrained at the intersection of a straight guide groove 11 and an arc-shaped guide groove 12.

[0031] First, let's define some terms: First radius threshold: The system-preset lower limit (minimum) for radius adjustment, denoted as... .

[0032] Second radius threshold: The system's preset upper limit (maximum value) for radius adjustment, denoted as... .

[0033] First radius: Generally refers to the radius value actually used in a specific measurement step. In a traversal scanning strategy, it is the first radius actually used during the initial acquisition. Equal to the first radius threshold (i.e. ).

[0034] Method for determining the radius threshold: The determination of the first radius threshold (minimum radius) mainly considers two factors: the highest operating frequency and physical and mechanical limitations.

[0035] 1) Avoid high-frequency grating lobes: For A uniform circular array, with the arc length spacing between adjacent microphones approximately... R is the array radius. To avoid operating at the highest frequency... The appearance of grid lobes requires the following conditions to be met. ,in , The speed of sound is approximately 343 m / s. Therefore, the theoretical maximum permissible radius can be obtained as follows: In this embodiment, , The theoretical value calculated is approximately 1.1 cm.

[0036] 2) Physical and mechanical limitations: The microphone unit itself has certain physical dimensions and a minimum installation spacing. .

[0037] Taking all the above factors into account, the first radius threshold value is: The final setting was 2 cm.

[0038] The determination of the second radius threshold (maximum radius) mainly considers the minimum operating frequency and device portability: to achieve the minimum operating frequency To achieve a sufficiently narrow main lobe (high spatial resolution), the array aperture should be as large as possible. Theoretically, the larger the radius, the better, but due to the wearing comfort and overall size of VR / AR devices, the array radius cannot be increased indefinitely. In this embodiment, after weighing the resolution and portability, the following parameters are set: .

[0039] like Figure 4 The rotation of the outer ring frame 2 causes the microphone unit 3 to move radially along the straight guide groove 11, thereby changing the radius of the microphone array. The radius changes from the first radius threshold R. min To the second radius threshold R max Change.

[0040] Example 2 This embodiment relates to a beamforming system for broadband signal reception, comprising: A reconfigurable circular microphone array, comprising the microphone array and a double-layer ring support. Microphone array: Employs an 8-channel microphone array, each microphone unit being a condenser electret microphone, connected to the host via a USB sound card, with a sampling rate set to 192kHz to ensure distortion-free acquisition of high-frequency audio signals. Double-layer ring support: To achieve dynamic adjustment of the array radius, a double-layer circular ring support structure is constructed (see reference). Figures 2-4 ).like Figure 2 Eight radially extending straight guide grooves are formed on the fixed inner ring frame; such as Figure 3 The rotatable outer ring has eight arc-shaped guide grooves, the trajectories of which satisfy the Archimedean spiral equation. For example... Figure 4Eight microphone units are positioned at the intersection of the inner and outer guide slots (straight guide slots and curved guide slots). When the outer ring rotates, the curved guide slots drive the microphone units to slide along the straight guide slots, thereby enabling continuous adjustment of the array radius between a first radius threshold (e.g., 2cm) and a second radius threshold (e.g., 5cm).

[0041] The double-layer ring support structure uses the inner ring as a supporting reference to ensure structural stability, while the outer ring drives the microphone unit to move via an arc-shaped guide groove. Continuous adjustment of the array radius can be achieved simply by rotating the outer ring, providing a stable and reliable mechanical basis for dynamic adjustment of the array radius. This structure simplifies the mechanical structure, reduces the size and complexity of the equipment, and avoids the wear and misalignment problems associated with linear drive mechanisms, thus improving the system's reliability and durability.

[0042] Motion Control Module: The outer ring frame is driven by a servo motor, which is precisely controlled by a microcontroller using pulse-width modulation (PWM) signals. The microcontroller adjusts the rotation angle of the servo motor according to instructions from the host computer, thereby precisely adjusting the microphone array radius to the target value. Actual measurements show that a complete radius adjustment cycle (2cm to 5cm) takes less than 0.8 seconds, meeting real-time requirements and quickly adapting to frequency changes in the target signal. This outer ring frame rotation drive method achieves automation and precision in array radius adjustment. It significantly reduces the algorithm complexity and computational load of the motion control module; simultaneously, the rotation drive has high mechanical transmission efficiency and fast response speed, completing a radius adjustment of 2cm to 5cm within 0.8 seconds, enabling rapid adaptation to dynamic frequency changes in wideband signals and meeting the latency requirements of real-time interactive scenarios.

[0043] Signal processing module: All control command transmission and signal processing algorithms run on a laptop equipped with a high-performance processor. The host computer communicates with the microcontroller through the MATLAB environment and executes beamforming and blur suppression algorithms (i.e., intermediate spatial spectrum fusion).

[0044] The system can be deployed compatible with VR head-mounted displays, such as... Figure 5 The receiver beam, formed through adjustable radius and ambiguity suppression, is used for intelligent voice interaction, in-vehicle voice noise reduction, and other applications. Compared with traditional receiver beams, it achieves high spatial resolution and low ambiguity.

[0045] To verify the superiority of this invention over existing technologies, a quantitative comparative experiment was conducted in a controlled acoustic environment. The experimental environment was a 7m×7m×3m indoor room, and the ambient noise included air conditioning operation noise, human voices, etc. The sound source was a loudspeaker placed 2 meters away from the array.

[0046] Comparison: The system of the present invention is compared with two existing fixed array designs: (1) Fixed circular array: an 8-element uniform circular array with a fixed radius of 4cm; (2) Fixed spiral array: an 8-element spiral non-uniform array with a radius increasing from 2cm to 5.5cm.

[0047] Evaluation indicators: (1) Average error (ME): the average deviation between the estimated angle and the actual angle, which measures the accuracy; (2) Normalized maximum fuzzy peak (NMP): the ratio of the highest fuzzy side lobe to the main lobe, which measures the fuzziness suppression capability. The lower the value, the better; (3) Half power beamwidth (HPBW): the width of the main lobe, which measures the spatial resolution. The narrower the value, the better.

[0048] Test results: Tests were conducted at frequencies of 5kHz, 10kHz, 15kHz, and 20kHz, and the average values ​​of each indicator were taken. The results are shown in Table 1.

[0049] Table 1 Results and Conclusions: Experiments show that the system of this invention achieves both high spatial resolution and low ambiguity over a wide frequency range. Compared with a fixed circular array, the average estimation error is reduced by 34.2%, the ambiguity peak is reduced by 42.9%, and the beamwidth is narrowed by 49.6%. The performance is significantly better than that of the traditional fixed array design, verifying the effectiveness and adaptability of this invention in complex acoustic environments.

[0050] Example 3 This embodiment also relates to a beamforming method for broadband signal reception, applied to the system of Embodiment 1.

[0051] The method includes the following steps: Step S1: Signal Acquisition and Frequency Analysis: Acquire sound source signals with a first radius using a reconfigurable circular microphone array, and perform time-frequency analysis to determine the frequency components of the target signal; Step S2: Multi-radius signal acquisition: Based on the frequency components of the target signal, the radius of the microphone array is gradually adjusted from the first radius threshold to the second radius threshold through the motion control module, and multi-channel acoustic signals are acquired under at least two different radius configurations; Step S3: Intermediate Spatial Spectrum Generation: For the signals acquired under each radius configuration, a beamforming algorithm is applied to generate the corresponding intermediate spatial spectrum. ,in Indicates the first Secondary radius configuration. It is the azimuth angle. The pitch angle; Step S4: Fusion of intermediate spatial spectra with multiple radii: To suppress grating lobes, intermediate spatial spectra generated with multiple radii are weighted and fused to generate a combined spatial spectrum. The fusion formula is: , in, These are the weighting coefficients; Furthermore, weighting coefficients Determined based on the maximum ratio merging principle, and with the th The variance of the second estimate Inversely proportional, that is In practical implementation, an approximate ratio is used. Weighting is applied.

[0052] By fusing multiple intermediate spatial spectra, grating lobes are completely canceled out, achieving unambiguous high-resolution positioning. For example... Figure 6 As shown, the position of the grating lobe shifts under different radii while the position of the main lobe remains unchanged. The grating lobe can be effectively eliminated by weighted fusion, and the spurious peaks caused by random noise are also weakened.

[0053] Step S5: Sound source direction estimation: Detect the peak value of the combined spatial spectrum and determine the angle corresponding to the peak value. As the final estimated direction of the sound source.

[0054] Furthermore, in step S1, when the sound source emits sound, the reconfigurable circular microphone array collects the sound signal with a minimum radius (2cm). The host computer performs a short-time Fourier transform on the collected signal, analyzes its frequency components, and determines the dominant frequency of the target signal.

[0055] Furthermore, in step S2, based on the dominant frequency of the target signal, the motion control module controls the rotation of the outer ring frame, gradually increasing the array radius from 2cm to 5cm. Under each radius configuration, the system acquires a segment of multi-channel acoustic signal and transmits it to the host computer.

[0056] Furthermore, the beamforming algorithm in step S3 is the MUSIC algorithm. For the selected frequency f, the intermediate spatial spectrum calculation formula is: , in, This is the steering vector. The noise subspace matrix, The azimuth angle is And pitch angle The MUSIC spatial spectrum, with the superscript H indicating conjugate transpose.

[0057] Alternatively, the beamforming algorithm can be replaced with the ESPRIT algorithm or a deep learning-based neural network algorithm.

[0058] Example 4 The electronic device of this invention includes a central processing unit (CPU), which can perform various appropriate actions and processes according to computer program instructions stored in read-only memory (ROM) or loaded from a storage unit into random access memory (RAM). The RAM may also store various programs and data required for device operation. The CPU, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0059] Multiple components in the device are connected to the I / O interface, including: input units such as keyboards and mice; output units such as various types of displays and speakers; storage units such as disks and optical discs; and communication units such as network interface cards (NICs), modems, and wireless transceivers. The communication unit allows the device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0060] The processing unit performs the various methods and processes described above. For example, in some embodiments, the methods may be implemented as computer software programs tangibly contained in a machine-readable medium, such as a storage unit. In some embodiments, part or all of the computer program may be loaded and / or installed on the device via ROM and / or a communication unit. When the computer program is loaded into RAM and executed by the CPU, one or more steps of the methods described above may be performed. Alternatively, in other embodiments, the CPU may be configured to execute the methods by any other suitable means (e.g., by means of firmware).

[0061] The functions described above in this document can be performed, at least in part, by one or more hardware logic components. For example, exemplary types of hardware logic components that can be used, without limitation, include: Field Programmable Gate Arrays (FPGAs), Application-Specific Integrated Circuits (ASICs), Application Standard Products (ASSPs), System-on-Chip (SoCs), Complex Programmable Logic Devices (CPLDs), and so on.

[0062] The program code used to implement the methods of the present invention can be written in any combination of one or more programming languages. This program code can be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code can be executed entirely on the machine, partially on the machine, as a standalone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0063] In the context of this invention, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory, optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0064] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A beamforming system for broadband signal reception, characterized in that, The system includes: A reconfigurable circular microphone array, consisting of several microphone units, is used to collect multi-channel acoustic signals under different radius configurations; A motion control module connected to a reconfigurable circular microphone array is used to adaptively control the radius change of the reconfigurable circular microphone array according to the frequency of the target signal. The system also includes a signal processing module for receiving multi-channel signals acquired by the reconfigurable circular microphone array, applying a beamforming algorithm to generate corresponding intermediate spatial spectra for each radius, fusing multiple intermediate spatial spectra to generate a combined spatial spectrum with suppressed grating lobes, and outputting a direction estimate of the sound source based on the combined spatial spectrum.

2. The beamforming system for broadband signal reception according to claim 1, characterized in that, The reconfigurable circular microphone array is a double-layer ring structure, comprising: A fixed inner ring frame is provided with several radially extending straight guide grooves; The outer ring frame is rotatable and has several arc-shaped guide grooves on it; The outer ring frame and the inner ring frame are coaxially arranged and can rotate relative to each other. The outer ring frame and the inner ring frame are connected by a coaxial rotary support structure, which is fitted and installed on the outer edge of the inner ring frame. Each of the microphone units is simultaneously constrained at the intersection of one of the straight guide slots and one of the arc-shaped guide slots; The coaxial rotatable connection structure is any one of the following: 1) Bearing rolling fit structure; 2) Sliding clearance fit structure.

3. A beamforming system for broadband signal reception according to claim 2, characterized in that, The outer ring frame is coaxially connected to the inner ring frame via an independent support base.

4. A beamforming system for broadband signal reception according to claim 2, characterized in that, The motion control module controls the rotation of the outer ring frame. Through the synergistic effect of the arc-shaped guide groove and the straight guide groove, it drives the microphone unit to move radially along the straight guide groove, thereby changing the radius of the microphone array.

5. A beamforming system for broadband signal reception according to claim 2, characterized in that, The trajectory of the arc-shaped guide groove satisfies a preset polar coordinate equation, so that the radial movement distance of the microphone unit is linearly related to the rotation angle of the outer ring frame.

6. A beamforming system for broadband signal reception according to claim 5, characterized in that, The trajectory of the arc-shaped guide groove is an Archimedean spiral.

7. A beamforming method for broadband signal reception, characterized in that, This method is applied to a beamforming system for broadband signal reception as described in any one of claims 1 to 6, the method comprising: The motion control module controls the reconfigurable circular microphone array to acquire multi-channel acoustic signals in multiple different radius configurations; For each radius configuration, the signal processing module uses a beamforming algorithm to generate a corresponding intermediate spatial spectrum from the acoustic signals acquired; multiple intermediate spatial spectra are then fused to generate a combined spatial spectrum. The signal processing module detects the peak value of the combined spatial spectrum and uses the angle corresponding to the peak value as the direction of arrival of the sound source.

8. A beamforming method for broadband signal reception according to claim 7, characterized in that, The controllable reconfigurable circular microphone array acquires multi-channel acoustic signals in multiple different radius configurations, including: The motion control module controls the reconfigurable circular microphone array to acquire sound source signals at a first radius threshold, and performs time-frequency transformation on the acquisition results to determine the dominant frequency of the target signal; Based on the dominant frequency of the target signal, the motion control module gradually adjusts the radius of the reconfigurable circular microphone array from a first radius threshold to a second radius threshold, and acquires multi-channel acoustic signals under at least two different radius configurations.

9. A beamforming method for broadband signal reception according to claim 7, characterized in that, The reconfigurable circular microphone array is a double-layer ring structure, comprising: A fixed inner ring frame is provided with several radially extending straight guide grooves; The outer ring frame is rotatable and has several arc-shaped guide grooves on it; The outer ring frame and the inner ring frame are coaxially arranged and can rotate relative to each other. The outer ring frame and the inner ring frame are connected by a coaxial rotary support structure, which is fitted and installed on the outer edge of the inner ring frame. Each of the microphone units is simultaneously constrained at the intersection of one of the straight guide slots and one of the arc-shaped guide slots; The motion control module controls the rotation of the outer ring frame. Through the synergistic effect of the arc-shaped guide groove and the straight guide groove, it drives the microphone unit to move radially along the straight guide groove, thereby changing the radius of the microphone array.

10. A beamforming method for broadband signal reception according to claim 7, characterized in that, The beamforming algorithms include the MUSIC algorithm, the ESPRIT algorithm, and a deep learning-based neural network algorithm.

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