Sound Source Direction Estimation Using Spatial Correlation Filters
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Solution Overview
Problem
Conventional methods face challenges in robustly estimating the arrival direction of sound from a sound source with lower computational cost, especially in noisy environments and when the sound source is not fixed.
Innovation Solution
An estimation device is configured with a conversion module for time frequency conversion of acoustic signals, a spatial correlation calculation module for calculating spatial correlation matrices, a spatial correlation filter module for generating spatial correlation filters, and a direction estimation module that estimates general direction information from partial elements of the spatial correlation filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional beam forming methods are used to estimate sound source direction, then direction estimation can be performed, but computational cost increases and robustness decreases
Solution Approach 1:
The patent extracts only the necessary spatial correlation information from the full spatial correlation filter. By using a reduced set of equations that calculate spatial correlation between specific microphone pairs rather than all possible pairs, the system achieves direction estimation with significantly lower computational cost while maintaining robustness.
Solution Approach 2:
The patent segments the direction estimation process into two stages: first calculating spatial correlation for selected microphone pairs, then using these partial correlations to estimate direction. This segmentation allows the system to avoid the full computational burden of conventional beam forming while preserving essential directional information.
2Reliability
If conventional beam forming is used in noisy environments, then direction estimation is attempted, but robustness against noise deteriorates
Solution Approach 1:
The patent converts the harmful effect of noise into a benefit by using spatial correlation properties that are inherently more robust to noise than conventional beam forming. The spatial correlation approach naturally suppresses uncorrelated noise while preserving correlated signal components, turning noise resistance into a strength rather than a weakness.
3Loss of information
If full spatial correlation filter is calculated, then complete spatial information is obtained, but computational complexity increases
Solution Approach 1:
The patent applies partial action by calculating spatial correlation only for specific microphone pairs that provide sufficient directional information, rather than computing the complete spatial correlation filter. This partial calculation achieves the necessary directional estimation without the excessive computational cost of full spatial correlation analysis.
Data Source
AI summary
According to one embodiment, an estimation device includes one or more hardware processors configured to function as: a conversion module configured to perform time frequency conversion on acoustic signals of a plurality of channels to acquire a frequency spectrum; a spatial correlation calculation module configured to calculate a spatial correlation matrix from the frequency spectrum; a spatial correlation filter module configured to calculate a spatial correlation filter from the spatial correlation matrix; and a direction estimation module configured to estimate general direction information from a partial element included in the spatial correlation filter.