TY - CHAP A1 - Povey, Daniel A1 - Hannemann, Mirko A1 - Boulianne, Gilles A1 - Burget, Lukáš A1 - Ghoshal, Arnab A1 - Janda, Miloš A1 - Karafiát, Martin A1 - Kombrink, Stefan A1 - Motlíček, Petr A1 - Qian, Yanmin A1 - Riedhammer, Korbinian A1 - Veselý, Karel A1 - Thang Vu, Ngoc T1 - Generating Exact Lattices in the WFST Framework T2 - 2012 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Kyoto, Japan, May 2012. N2 - We describe a lattice generation method that is exact, i.e. it satisfies all the natural properties we would want from a lattice of alternative transcriptions of an utterance. This method does not introduce substantial overhead above one-best decoding. Our method is most directly applicable when using WFST decoders where the WFST is “fully expanded”, i.e. where the arcs correspond to HMM transitions. It outputs lattices that include HMM-state-level alignments as well as word labels. The general idea is to create a state-level lattice during decoding, and to do a special form of determinization that retains only the best-scoring path for each word sequence. This special determinization algorithm is a solution to the following problem: Given a WFST A, compute a WFST B that, for each input-symbol-sequence of A, contains just the lowest-cost path through A. KW - Speech Recognition KW - Lattice Generation Y1 - 2012 SP - 4213 EP - 4216 ER -