Speech enhancement with improved a posteriori SNR computation

In speech enhancement, the decision-directed (DD) approach to compute the a priori SNR is often used to reduce the musical tones. However, the constant DD weighting factor very close to one results in more speech distortion during transitional speech segments. Contrarily, a time-varying weighting factor gives less speech distortion but with more residual noise in speech pause. In this contribution we present a new a posteriori SNR computation to relax the dependence on the decision-directed weighting factor. By computing the a posteriori SNR with a timevarying weighting factor, we actually derive a correction factor to the time-varying DDweighting factor resulting in less speech distortion during transitions, as well as less residual noise in speech pause.