A method and a system are disclosed for normalizing a speech signal prior to a speech recognition process. In a preparatory procedure, a sample interval of speech is separated into thirty-one frequency bands and an amplitude histogram is generated for each band. From these histograms, the 5% percentile...http://www.google.ca/patents/US4817158?utm_source=gb-gplus-sharePatent US4817158 - Normalization of speech signals
