5th International Conference on Spoken Language Processing

Sydney, Australia
November 30 - December 4, 1998

Double Tree Beam Search Using Hierarchical Subword Units

Juan Carlos Torrecilla, Ismael Cortazar, Luis A. Hernandez

Telefonica Investigacion Y Desarrollo, Spain

In this paper we proposed an efficient beam search procedure that combines well-known search techniques as a lexicon organization using tree-structured grammars with a novel approach of using different types of subword units depending on the local scores of the active words. An efficient double-tree structure using phonemes and triphones is presented. Experimental results on an isolated word recognition systems reveals that the proposed strategy is suitable for important reductions in computational cost with only negligible increases in recognition errors. Tests over a vocabulary of 955 Spanish words presents a 0.5% of increase in error rate for a 32% reduction in the number of senones to be evaluated.

Full Paper

Bibliographic reference.  Torrecilla, Juan Carlos / Cortazar, Ismael / Hernandez, Luis A. (1998): "Double tree beam search using hierarchical subword units", In ICSLP-1998, paper 0321.