Julius-an Open Source Real-Time Large Vocabulary Recognition Engine

Akinobu Lee, Graduate School of Information Science, Nara Institute of Science and Technology, Japan, Tatsuya Kawahara, School of Informatics, Kyoto University, Japan, and Kiyohiro Shikano, Graduate School of Information Science, Nara Institute of Science and Technology, Japan

12/22/2008
(Original Publish Date: 3/3/2001)

Julius is a high-performance, two-pass LVCSR decoder for researchers and developers. Based on word 3-gram and context-dependent HMM, it can perform almost realtime decoding on most current PCs in 20k word dictation task. Major search techniques are fully incorporated such as tree lexicon, N-gram factoring, cross-word context dependency handling, enveloped beam search, Gaussian pruning, Gaussian selection, etc. Besides search efficiency, it is also modularized carefully to be independent from model structures, and various HMM types are supported such as shared-state triphones and tiedmixture models, with any number of mixtures, states, or phones. Standard formats are adopted to cope with other free modeling toolkit. The main platform is Linux and other Unix workstations, and partially works on Windows. Julius is distributed with open license together with source codes, and has been used by many researchers and developers in Japan.