Phone-Conditioned Suboptimal Wiener Filtering

A novel way of managing the compromise between noise reduction and speech distortion in Wiener filters is presented. It is based on adjusting the amount of noise reduced, and therefore the speech distortion introduced, on a phone-by-phone basis. We show empirically that optimal Wiener filters produce different amounts of speech distortion for different phones. Therefore we propose a phone-conditioned suboptimal Wiener filter that uses different amounts of noise reduction for each phone, based on a previous estimation of the amount of distortion introduced. Speech recognition results have shown that phone conditioning suboptimal Wiener filtering can provide almost a 5% additional relative improvement in word accuracy over comparable optimal Wiener filtering.