Single-Frame Vowel Recognition Using Vector Quantization With Several Distance Measures

One of the most fundamental concepts used in the standard pattern recognition model for speech recognition is that of distance between pairs of frames of speech. Several distance measures have been proposed and studied in the context of an overall speech recognizer. The purpose of this investigation was to isolate the effects of different distance measures in a recognizer from the other types of processing typically used in recognition. The way in which this isolation was achieved was to use a recognizer based on single-frame distance scores, using a vector quantization approach to give the single-frame reference patterns required by the recognizer. The vocabulary for recognition was the set of continuant vowels extracted from carrier words. A speaker-dependent vowel recognition experiment was carried out using seven talkers (four male, three female) and five distance measures. Results indicated that there were differences in performance for the different distance measures when the number of code-book patterns per vowel was one or two; however, when the number of code-book patterns was four or more, these differences in performance became insignificant.