Data-Driven White Noise Gain Constrained Robust Superdirective Beamformer for Speech Enhancement

Superdirective beamformers are highly effective at suppressing directional interference and diffuse noise, but their practical use is often constrained by the problem of white noise amplification. Robust superdirective beamforming methods typically address this by imposing a constraint on the white noise gain (WNG). However, determining the appropriate WNG threshold in varying noise environments remains unclear. This paper introduces a data-driven approach to estimating the optimal WNG threshold. Subsequently, a more versatile and robust superdirective beamformer is developed by solving a quadratic eigenvalue problem (QEP). Experimental results show that this method outperforms traditional superdirective beamformers, which rely on a WNG threshold set through a fixed search range. Importantly, this approach functions as a distortionless beamformer, maintaining high fidelity of the desired acoustic signal and allowing for additional post-filtering if required.