- Paul Lamere, Philip Kwok, W. E. Gouvêa, Rita Singh, Bhik, I. Walker, Shankar raj, Peter Wolf. 2003. DESIGN OF THE CMU SPHI. Abstract: Sphinx-4 is an open source HMM-based speech recognition system written in the JavaTM programming language. The design of the Sphinx-4 decoder incorporates several new features in response to current demands on HMM-based large vocabulary systems. Some new design aspects include graph construction for multilevel parallel decoding with multiple feature streams without the use of compound HMMs, the incorporation of a generalized search algorithm that subsumes Viterbi decoding as a special case, token stack decoding for efficient maintenance of multiple paths during search, design of a generalized language HMM graph from grammars and language models of multiple standard formats, that can potentially toggle between flat search structure, tree search structure, etc. This paper describes a few of these design aspects, and reports some preliminary performance measures for speed and accuracy.
