Speech dereverberation using backward estimation of the late reverberant spectral variance

In speech communication systems the received microphone signals are degraded by room reverberation and ambient noise. This signal degradation can decrease the fidelity and intelligibility of the desired speaker. Reverberant speech can be separated into two components, viz. an early speech component and a late reverberant speech component. Reverberation suppression algorithms, that are feasible in practice, have been developed to suppress late reverberant speech or in other words to estimate the early speech component. The main challenge is to develop an estimator for the so-called late reverberant spectral variance (LRSV). In this contribution a generalized statistical reverberation model is proposed that can be used to estimate the LRSV. Novel and existing estimators can be derived from this model. One novel estimator is a so-called backward estimator that uses an estimate of the early speech component to obtain an estimate of the LRSV. Advantages and possible disadvantages of the estimators are discussed, and experimental results using simulated reverberant speech are presented.