Microphone Array Beamforming for Low Frequency Resolution
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Solution Overview
Problem
Conventional beamformer technologies using microphone arrays face limitations in resolving low frequency band signals due to insufficient size of the microphone array, leading to increased manufacturing costs and space constraints when trying to improve resolution performance.
Innovation Solution
A sound source signal processing apparatus that includes a first and second sound source detection unit with a beamforming unit, utilizing relative position information between the units to beamform sound source signals, allowing for increased size without adding more microphones, thereby enhancing resolution performance and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the size of the microphone array is increased to improve resolution performance for low frequency signals, then the beamforming effect is improved, but the manufacturing cost and installation space requirements increase
Solution Approach 1:
The patent combines multiple microphone arrays with different configurations into a single integrated system. The first microphone array uses microphones arranged in a specific geometric pattern (e.g., tetrahedral configuration), while the second array uses a different arrangement. By merging these arrays and sharing common microphones between them, the system achieves the resolution performance of larger arrays without proportionally increasing the total number of microphones, thus reducing manufacturing costs while maintaining beamforming effectiveness for low frequency signals
2Measurement precision
If the number of microphones in the array is increased to improve beamforming effect, then the resolution performance is improved, but the manufacturing cost increases
Solution Approach 1:
The patent merges multiple microphone arrays that share common microphones. Specifically, the first microphone array and second microphone array have overlapping microphone positions, allowing the same physical microphones to serve multiple array configurations. This reduces the total number of microphones required while maintaining the mathematical equivalence of larger arrays for beamforming calculations
Solution Approach 2:
Each microphone in the system serves multiple functions by belonging to different array configurations simultaneously. The same microphone array can be used for different beamforming modes (e.g., omnidirectional, directional, narrowbeam) by applying different weight coefficients and processing algorithms, eliminating the need for dedicated microphones for each function
3Measurement precision
If the distance between microphones is increased to improve low frequency signal detection, then the resolution performance is improved, but the installation space required increases
Solution Approach 1:
The patent transitions from two-dimensional microphone arrangements to three-dimensional spatial configurations. By arranging microphones in volumetric patterns (such as tetrahedral or spherical configurations) rather than flat arrays, the system achieves larger effective baseline distances for low frequency detection without proportionally increasing the footprint area. The third dimension allows microphones to be positioned at greater mutual distances while maintaining a compact overall installation envelope
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus effectively improves beamforming for low frequency band signals, such as voice signals, by increasing the size of the microphone array without increasing the number of microphones, resulting in improved resolution and reduced manufacturing costs while effectively filtering noise and maintaining important low frequency signals.
Implementation Method 1
a first sound source detection unit having at least one microphone to detect a sound source signal
Implementation Method 2
The beamformer finds the direction of a sound using a time difference between signals reaching the respective microphones arranged in the array
Implementation Method 3
This is distinguished only when a phase difference caused by time delay between the neighboring microphones is 2π or less
Data Source
AI summary
A sound source signal processing apparatus including a first sound source detection unit having at least one microphone to detect a sound source signal, a second sound source detection unit having at least one microphone to detect the sound source signal, the second sound source detection unit being spaced apart from the first sound source detection unit, and a beamforming unit to beamform the sound source signal detected by the first sound source detection unit and the second sound source detection unit. At least one microphone is further provided in addition to the microphone array, and position information of the microphones and sound source information are used, thereby improving beamforming performance of the sound source signal. Also, the number and size of microphone arrays is reduced through further provision of the at least one microphone, thereby improving spatial utilization.