Audio Source Localization Using Spatial Beamforming
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Solution Overview
Problem
Conventional audio source localization methods are suboptimal and resource-intensive, particularly when dealing with two simultaneous sound sources with similar characteristics, as they rely on temporal or frequency differences that often break down for signals with similar characteristics.
Innovation Solution
An audio source localization apparatus using a microphone array with at least three microphones, generating reference beams with different directional properties, and an estimation circuit that combines these signals to determine direction estimates based on spatial characteristics, reducing sensitivity to similar audio signals and improving accuracy with low computational resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional time or frequency difference-based methods are used to separate sound sources, then direction estimation can be performed for sound sources with distinct characteristics, but the method breaks down and becomes unreliable for sound sources with similar characteristics
Solution Approach 1:
The patent changes the fundamental parameters used for sound source separation from temporal/frequency characteristics to spatial characteristics. By using microphone array geometry and signal phase differences across multiple spatial locations, the method can reliably distinguish between sound sources even when their audio content is similar, thus improving both reliability and adaptability
Solution Approach 2:
The patent introduces spatial dimension as an additional degree of freedom for sound source separation. Instead of relying solely on time or frequency differences, the method utilizes the spatial arrangement of microphones and the directional properties of sound waves, adding a spatial dimension to the separation problem that enables reliable estimation for similar sound sources
2Measurement precision
If conventional sound source localization methods are used, then direction estimates can be generated for sound sources with significant temporal or frequency differences, but the computational complexity and resource consumption increase significantly
Solution Approach 1:
The patent extracts and utilizes only the essential spatial characteristics from the microphone signals, separating the directional information extraction from complex temporal and frequency analysis. By focusing on spatial phase differences and using simplified mathematical models based on microphone geometry, the method achieves accurate direction estimation with reduced computational complexity
Solution Approach 2:
The patent changes the computational approach by using closed-form mathematical solutions based on spatial geometry rather than iterative optimization methods. This parameter change in the computational strategy maintains measurement precision while significantly reducing device complexity and resource consumption
Data Source
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AI summary
An audio source localization apparatus receives signals from a microphone array (101), and a reference processor (105) generates at least three reference beams with different directional properties. An estimation processor (107) which generates simultaneous direction estimates for two sound sources, comprises a circuit (401) combining signals of the at least three reference beams with a beam shape parameter reflecting a shape of an audio beamform and a beam direction parameter reflecting a direction of an audio beamform for the combined signal. A cost processor (403) generates a cost measure indicative of an energy of the combined signal and a minimization processor (405) estimates values of the beam shape parameter and the beam direction parameter which correspond to a local minimum of the cost measure. A direction processor (407) then determines simultaneous direction estimates for two sound sources from the determined parameter values. Improved direction estimation for two simultaneous sound sources may be achieved.