ABSTRACT
Speech enhancement aims at improving the performance of speech communication systems in noisy environments. Speech enhancement may be applied, for example, to a mobile radio communication system, a speech recognition system, a set of low quality recordings, or to improve the performance of aids for the hearing impaired. Both the quality and intelligibility are elaborate and expensive to measure, since they require listening sessions with live subjects. Thus, researchers often resort to less formal listening tests to assess the quality of an enhanced signal, and they use automatic speech recognition tests to assess the intelligibility of that signal. Estimation of speech signals second-order statistics from training data has proven successful in coding and recognition of clean speech signals. This is commonly done in coding applications using vector quantization and in recognition applications using hidden Markov modeling. On-line estimation of second-order statistics of a speech signal from a sample function of the noisy signal has proven to be a better choice.
