Wideband Relative Transfer Function (RTF) Estimation Exploiting Frequency Correlations

Fuente: arXiv
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Autores principales: Bologni, Giovanni, Hendriks, Richard C., Heusdens, Richard
Formato: Preprint
Publicado: 2024
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author Bologni, Giovanni
Hendriks, Richard C.
Heusdens, Richard
author_facet Bologni, Giovanni
Hendriks, Richard C.
Heusdens, Richard
contents This article focuses on estimating relative transfer functions (RTFs) for beamforming applications. Traditional methods often assume that spectra are uncorrelated, an assumption that is often violated in practical scenarios due to factors such as time-domain windowing or the non-stationary nature of signals, as observed in speech. To overcome these limitations, we propose an RTF estimation technique that leverages spectral and spatial correlations through subspace analysis. Additionally, we derive Cramér--Rao bounds (CRBs) for the RTF estimation task, providing theoretical insights into the achievable estimation accuracy. These bounds reveal that channel estimation can be performed more accurately if the noise or the target signal exhibits spectral correlations. Experiments with both real and synthetic data show that our technique outperforms the narrowband maximum-likelihood estimator, known as covariance whitening (CW), when the target exhibits spectral correlations. Although the proposed algorithm generally achieves accuracy close to the theoretical bound, there is potential for further improvement, especially in scenarios with highly spectrally correlated noise. While channel estimation has various applications, we demonstrate the method using a minimum variance distortionless (MVDR) beamformer for multichannel speech enhancement. A free Python implementation is also provided.
format Preprint
id arxiv_https___arxiv_org_abs_2407_14152
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Wideband Relative Transfer Function (RTF) Estimation Exploiting Frequency Correlations
Bologni, Giovanni
Hendriks, Richard C.
Heusdens, Richard
Audio and Speech Processing
Signal Processing
This article focuses on estimating relative transfer functions (RTFs) for beamforming applications. Traditional methods often assume that spectra are uncorrelated, an assumption that is often violated in practical scenarios due to factors such as time-domain windowing or the non-stationary nature of signals, as observed in speech. To overcome these limitations, we propose an RTF estimation technique that leverages spectral and spatial correlations through subspace analysis. Additionally, we derive Cramér--Rao bounds (CRBs) for the RTF estimation task, providing theoretical insights into the achievable estimation accuracy. These bounds reveal that channel estimation can be performed more accurately if the noise or the target signal exhibits spectral correlations. Experiments with both real and synthetic data show that our technique outperforms the narrowband maximum-likelihood estimator, known as covariance whitening (CW), when the target exhibits spectral correlations. Although the proposed algorithm generally achieves accuracy close to the theoretical bound, there is potential for further improvement, especially in scenarios with highly spectrally correlated noise. While channel estimation has various applications, we demonstrate the method using a minimum variance distortionless (MVDR) beamformer for multichannel speech enhancement. A free Python implementation is also provided.
title Wideband Relative Transfer Function (RTF) Estimation Exploiting Frequency Correlations
topic Audio and Speech Processing
Signal Processing
url https://arxiv.org/abs/2407.14152