High Performance Chinese Continuous Digits Recognition System

摘要

Connected digits recognition, as a special recognition task of continuous speech recognition (CSR), keeps an active domain for many speech recognition researchers in recent years. For English languages, several high performance recognizer up to 99.7%[1][8] word accuracy were reported; whereas for Chinese digits, it is another case, 93%[2] string accuracy is the best result. Even though, in their systems, digits strings are not strictly continuously uttered in a natural mode, but connectedly; secondly they often ignored the most confusable digit 1 /yil/, instead with another pronunciation /yiaol/, which is easier to be recognized. In this paper, a real continuous unknown-length digits string recognition system was presented with spontaneous speaking rate is about 250～350 words/min (4～6 w/sec), moreover, both /yil/ and /yiaol/ were considered simultaneously. Espeically by introducing duration information into state and word, with modified Viterbi beam search, about 80～85% string errors reduction were achieved and almost imposed no overhead, futhermore several probability distribution of duration were compared.