Direction of Arrival Estimation Using Phase Aligned Correlation
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Solution Overview
Problem
Existing methods for estimating the direction of arrival (DOA) and delays of early room reflections are limited, particularly in blind scenarios where no additional information beyond microphone signals is available.
Innovation Solution
The proposed method employs Phase Aligned Correlation (PHALCOR), which involves transforming the spatial correlation matrix to enhance the separation of reflections with different delays, enabling the detection and localization of reflections with similar DOAs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If blind methods are used to estimate DOA and delays of early reflections, then no additional information beyond microphone signals is required, but the accuracy of reflection separation and localization deteriorates in reverberant environments
Solution Approach 1:
The patent segments the spatial correlation matrix into multiple delay representations through transformation, separating reflections with different delays into distinct components. This segmentation allows accurate identification and localization of individual reflections even in blind scenarios without additional information.
Solution Approach 2:
The patent transforms the spatial correlation matrix from the spatial domain to a delay domain through frequency-to-time transformation, adding a temporal dimension to the analysis. This dimensional transformation enables separation of reflections by delay while maintaining blind operation capabilities.
2Measurement precision
If spatial filtering and subspace methods are used for reflection estimation, then some separation capability is achieved, but reflections with similar DOAs cannot be effectively localized
Solution Approach 1:
The patent introduces a delay domain through frequency-to-time transformation of the spatial correlation matrix. This transforms the problem from purely spatial separation to joint delay-DOA separation, enabling effective localization of reflections with similar DOAs by exploiting their delay differences.
Solution Approach 2:
The patent changes the analysis parameters by transforming from spatial correlation to delay representations, and further to phase-aligned delay representations. This parameter transformation enhances the separability of reflections by emphasizing delay differences while maintaining DOA information.
3Measurement precision
If phase alignment transformation is applied to separate reflections by delay, then reflections with different delays are effectively separated, but the computational complexity increases
Solution Approach 1:
The patent applies phase alignment transformation as a preliminary step before delay detection and DOA estimation. By pre-aligning the phases of different frequency components, the transformation simplifies subsequent detection steps and enables more efficient computational processing of the delay representations.
Solution Approach 2:
The patent introduces phase-aligned delay representations as an intermediary form between the spatial correlation matrix and the final reflection parameters. This intermediate representation facilitates efficient computation by organizing the data in a structure that highlights delay differences while preserving spatial information.
Data Source
AI summary
Aspects of embodiments pertain to systems for estimating direction of arrival and delays of reflected and non-reflected sources in a room received by a plurality of sound capturing devices in the room, comprising obtaining sound data descriptive of received sources. Embodiments may further comprise determining, based on the sound data, a correlation value between each two audio channels of a plurality of audio channels to obtain, for a same frequency of the plurality of frequencies, a set of correlation values; and to perform a transform on each set of frequency-related correlation values to obtain a plurality of subsets of delay representations of a 3D Matrix. Each set of time delay representations may be analyzed or processed to extract information about the sources.