Wideband DOA Estimation via Eigenvalue Domain Covariance Merging

Solution Overview

Problem

Conventional narrow-band DOA estimation algorithms, such as the ESPRIT algorithm, are not robust and suffer from high computational complexity, making them inefficient for estimating the direction of arrival (DOA) of sound sources emitting wide-band signals.

Innovation Solution

The proposed method accumulates narrow-band signal statistics in the eigenvalue domain across all frequency bins to estimate DOAs directly, using Hadamard powering to rotate eigenvectors and reconstructing covariance matrices, resulting in a more robust and computationally efficient algorithm that is frequency-independent.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If narrow-band DOA estimation algorithms (e.g., ESPRIT) are applied to each frequency bin separately, then the algorithm can process wide-band signals, but the computational complexity is high and the estimation process is slow

Engineering Contradiction:

Improvecapability to process wide-band signalsVSAvoidcomputational complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the DOA estimation process across all frequency bins by accumulating narrow-band signal statistics in the eigenvalue domain to form a wide-band covariance matrix. This combines information from all frequency bins into a single estimation process, reducing computational complexity while maintaining the capability to process wide-band signals.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent transforms the problem from the time-frequency domain to the eigenvalue domain by performing eigenvalue decomposition on the wide-band covariance matrix. This dimensionality change allows the algorithm to exploit the structure of the problem in a different mathematical space, reducing computational burden.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If narrow-band DOA estimation algorithms are applied to each frequency bin separately, then the algorithm can estimate DOA for wide-band signals, but the estimation process is slow

Engineering Contradiction:

Improvecapability to estimate DOA for wide-band signalsVSAvoidestimation speed

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent merges the DOA estimation process across all frequency bins by accumulating narrow-band signal statistics in the eigenvalue domain to form a wide-band covariance matrix. This combines information from all frequency bins into a single estimation process, reducing computational complexity while maintaining the capability to process wide-band signals.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent performs preliminary accumulation of signal statistics and construction of the wide-band covariance matrix before the actual DOA estimation. This preliminary action organizes the data in a way that enables faster final estimation by avoiding repeated processing of individual frequency bins.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If narrow-band DOA estimation algorithms are applied to each frequency bin separately, then the algorithm can process wide-band signals, but the robustness is poor

Engineering Contradiction:

Improvecapability to process wide-band signalsVSAvoidrobustness

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent merges the DOA estimation process across all frequency bins by accumulating narrow-band signal statistics in the eigenvalue domain to form a wide-band covariance matrix. This combines information from all frequency bins into a single estimation process, reducing computational complexity while maintaining the capability to process wide-band signals.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent uses the accumulated wide-band covariance matrix to provide feedback about the overall signal structure across all frequency bins. This feedback mechanism allows the algorithm to adapt to the statistical properties of the wide-band signal, improving robustness by utilizing information from the entire frequency range rather than isolated narrow-band segments.

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP3698160B1Device and method for estimating direction of arrival of sound from a plurality of sound sources

Publication Date: 2023.03.15 HUAWEI TECH CO LTD

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AI summary

The invention provides a device (100) for estimating Direction of Arrival (DOA) of sound from Q sound sources (200) received by P microphone units (201), wherein P ≥ Q > 1. The device (100) is configured to transform (111) the output signals of the P microphone units (201) into the frequency domain and compute a covariance matrix for each of a plurality of N frequency bins in a range of frequencies of the sound. Further, the device (100) is configured to calculate (112) an adapted covariance matrix from each of the N covariance matrices for wide-band merging, calculate (113) an accumulated covariance matrix from the N adapted covariance matrices, and estimate (114) the DOA for each of the Q sound sources (200) based on the accumulated covariance matrix. In particular, in order to calculate (112) an adapted covariance matrix from a covariance matrix, the device (100) is configured to spectrally decompose (401) the covariance matrix and obtain a plurality of eigenvectors, rotate (403) each obtained eigenvector, and construct (404) each rotated eigenvector back to the shape of the covariance matrix to obtain the adapted covariance matrix.