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Lattices or word graphs are a condensed representation of the search space. Word graphs can be used in many way, including as an intermediate representation for a multipass speech recognition system. Word graphs normally contain word labels, start and stop times, a language model score and an acoustic score. This package performs four operations on word graphs: Accepts normal word graphs and generates augmented graphs with posterior scores. Computes the lattice word (or symbol) error rate. Prunes the links in the lattice based on a user-specified threshold. Converts a word graph to a confusion network and generates an output hypothesis. Each of the four operations is performed by separate utilities. Information about package installation and usage is provided in the AAREADME.text file provided with the package. To download the current version of the tools, click here. Also please feel free to send us comments or suggestions regarding the tools. The algorithm details of this package can be found in the following presentation: S. Raghavan and J. Picone, "Confidence Measures Using Word Posteriors and Word Graphs," IES Spring'05 Seminar Series, January 30, 2005.

We will continue to augment these tools as needs arise.