Nonlinear Compensation Using the Gauss–Newton Method for Noise-Robust Speech Recognition

摘要

In this paper, we present the Gauss–Newton method as a unified approach to estimating noise parameters of the prevalent nonlinear compensation models, such as vector Taylor series (VTS), data-driven parallel model combination (DPMC), and unscented transform (UT), for noise-robust speech recognition. While iterative estimation of noise means in a generalized EM framework has been widely known, we demonstrate that such approaches are variants of the Gauss–Newton method. Furthermore, we propose a novel noise variance estimation algorithm that is consistent with the Gauss–Newton principle. The formulation of the Gauss–Newton method reduces the noise estimation problem to determining the Jacobians of the corrupted speech parameters. For sampling-based compensations, we present two methods, sample Jacobian average (SJA) and cross-covariance (XCOV), to evaluate these Jacobians. The proposed noise estimation algorithm is evaluated for various compensation models on two tasks. The first is to fit a Gaussian mixture model (GMM) model to artificially corrupted samples, and the second is to perform speech recognition on the Aurora 2 database. The significant performance improvements confirm the efficacy of the Gauss–Newton method to estimating the noise parameters of the nonlinear compensation models.