ISCA Archive Interspeech 2015
ISCA Archive Interspeech 2015

Annotating large lattices with the exact word error

Rogier C. van Dalen, Mark J. F. Gales

The acoustic model in modern speech recognisers is trained discriminatively, for example with the minimum Bayes risk. This criterion is hard to compute exactly, so that it is normally approximated by a criterion that uses fixed alignments of lattice arcs. This approximation becomes particularly problematic with new types of acoustic models that require flexible alignments. It would be best to annotate lattices with the risk measure of interest, the exact word error. However, the algorithm for this uses finite-state automaton determinisation, which has exponential complexity and runs out of memory for large lattices. This paper introduces a novel method for determinising and minimising finite-state automata incrementally. Since it uses less memory, it can be applied to larger lattices.

doi: 10.21437/Interspeech.2015-560

Cite as: Dalen, R.C.v., Gales, M.J.F. (2015) Annotating large lattices with the exact word error. Proc. Interspeech 2015, 2625-2629, doi: 10.21437/Interspeech.2015-560

  author={Rogier C. van Dalen and Mark J. F. Gales},
  title={{Annotating large lattices with the exact word error}},
  booktitle={Proc. Interspeech 2015},