Smoothed time/frequency features for vowel classification

A novel signal modeling technique is described to compute smoothed time-frequency features for encoding speech information. These time-frequency features compactly and accurately model phonetic information, while accounting for the main effects of contextual variations. These segment-level features are computed such that more emphasis is given to the center of the segment and less to the end regions. For phonetic classification, the features are relatively insensitive to both time and frequency resolution, as least insofar as changes in window length and frame spacing are concerned. A 60-dimensional feature space based on this modeling technique resulted in 70.9% accuracy for classification of 16 vowels extracted from the TIMIT data base in speaker-independent experiments. These results are higher than any other results reported in the literature for the same task