Microphone Array Sound Source Probing via Correlation Matrix Learning
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Solution Overview
Problem
Existing sound source probing techniques face challenges in accurately determining the direction of a sound source when noise levels are higher than the sound source levels, as noise interference complicates the calculation of correlation matrices.
Innovation Solution
A sound source probing apparatus that determines a first correlation matrix from acoustic signals by learning weights to combine pre-calculated second correlation matrices, stored for various directions, to isolate sound pressure intensities, using methods like LMS or ICA to reduce noise interference and enhance detection speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a correlation matrix of noise signals is calculated based on acoustic signals acquired by microphone units, then the direction of sound source can be estimated, but when noise level is higher than sound source level, the accuracy of correlation matrix determination deteriorates
Solution Approach 1:
The patent segments the acoustic signals into multiple channels corresponding to different microphone units, and calculates correlation matrices for each channel separately. This segmentation allows the system to process and analyze signals from individual microphones independently, thereby improving the reliability of correlation matrix determination even in noisy environments by focusing on channel-specific characteristics rather than being overwhelmed by overall noise.
2Measurement precision
If acoustic signals are processed to determine sound source direction, then detection capability is achieved, but response time increases due to complex processing requirements
Solution Approach 1:
The patent performs preliminary calculations of correlation matrices for each microphone channel and stores them for future use. By pre-computing and storing these correlation matrices, the system avoids repeating complex calculations during real-time sound source detection, thereby significantly reducing processing time while maintaining detection accuracy.
Solution Approach 2:
The patent replaces complex mechanical signal processing with mathematical operations on pre-calculated correlation matrices. Instead of performing heavy real-time signal filtering and analysis, the system uses stored correlation matrices combined with simple mathematical computations to determine sound source direction, thereby substituting computationally intensive mechanical processing with efficient mathematical operations.
3Measurement precision
If multiple microphone units are used to improve sound source detection accuracy, then measurement precision increases, but device complexity increases
Solution Approach 1:
The patent makes each microphone unit universal by having all microphones perform the same function of acquiring acoustic signals and calculating their own correlation matrices. This multi-functionality approach allows the system to use multiple microphones for improved accuracy without increasing operational complexity, as each unit follows the same processing protocol independently.
Solution Approach 2:
Each microphone unit independently calculates and stores its own correlation matrix without requiring centralized processing or coordination. This self-service approach allows multiple microphones to contribute to improved detection accuracy while maintaining simple individual operation, thereby reducing overall system complexity despite using multiple units.
Data Source
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AI summary
A sound source probing apparatus, including storage and processing circuitry, is provided that probes a direction of a sound source. The processing circuitry performs operations including determining a first correlation matrix that is a correlation matrix of acoustic signals acquired as observation signals by a microphone array including two or more microphones disposed apart from each other. The operations also include determining, by learning, weights such that a linear sum of a plurality of second correlation matrices multiplied by the respective weights is equal to the first correlation matrix where the plurality of second correlation matrices are correlation matrices, which are determined for respective directions determined based on an array arrangement of the microphone array and which are stored in advance in the storage. The operations further include determining, using the determined weights, a spatial spectrum of the observation signal indicating sound pressure intensities in the respective directions.