International Symposium on Chinese Spoken Language Processing (ISCSLP 2002)

Taipei, Taiwan
August 23-24, 2002

Two-Pass Continuous Digit String Decoder

Zhi-yu Wang, Yuan Wen, Ming Li

Institute of Acoustics, Chinese Academy of Sciences, Beijing

In this paper, we present a two-pass continuous digit string decoder using two sets of whole-word HMM models. One set contains context-independent (CI) models used in the first-pass search. The first-pass search results in N-best hypotheses from which a N-best word lattice can be derived. The other set contains context-dependent (CD) HMM models used to search along the N-best word lattice for the best hypothesis, which is called the second-pass search. During the second-pass search, we introduce a tree-structured word lattice to speed up the second-pass search. Compared with one-pass decoder using only CI models, our two-pass decoder achieves 68% reduction of word error rate. Compared with one-pass decoder using only CD models, it achieves a 6.5 times faster search speed. Compared with two-pass decoder using flat-structured word lattice, it achieves about one time faster search speed.

Full Paper

Bibliographic reference.  Wang, Zhi-yu / Wen, Yuan / Li, Ming (2002): "Two-pass continuous digit string decoder", In ISCSLP 2002, paper 13.