Spatial Audio Signal Enhancement: A Multi-output MVDR Method in The Spherical Harmonic-domain

TL;DR

This paper introduces a novel spherical harmonic domain MVDR method for spatial audio enhancement that effectively reduces interference and preserves spatial cues in reverberant environments, outperforming existing approaches in simulation.

Contribution

The paper proposes a new multi-output MVDR approach using Relative Harmonic Coefficients for improved spatial audio signal enhancement in reverberant conditions.

Findings

Lower estimation error compared to baseline

Higher speech-distortion-ratio (SDR) achieved

Comparable noise reduction within the sweet area

Abstract

Spatial audio signal enhancement aims to reduce interfering source contributions while preserving the desired sound field with its spatial cues. Existing methods generally rely on impractical assumptions (e.g. accurate estimations of impractical information) or have limited applicability. This paper presents a spherical harmonic (SH)-domain minimum variance distortionless response (MVDR)-based spatial signal enhancer using Relative Harmonic Coefficients (ReHCs) to extract clean SH coefficients from noisy recordings in reverberant environments. A simulation study shows the proposed method achieves lower estimation error, higher speech-distortion-ratio (SDR), and comparable noise reduction (NR) within the sweet area in a reverberant environment, compared to a beamforming-and-projection method as the baseline.