The 1998 HTK broadcast news transcription system: development and results
PC Woodland, Thomas Hain, G.L. Moore, TR Niesler, Daniel Povey, Andreas Tuerk, Ewd Whittaker · White Rose Research Online (University of Leeds, The University of Sheffield, University of York) · 1999
This paper presents the development of the HTK broadcast news transcription system for the November 1998 Hub4 evaluation. Relative to the previous year's system The system a number of features were added including vocal tract length normalisation; cluster-based variance normalisation; double the quantity of acoustic training data; interpolated word level language models to combine text sources; increased broadcast news language model training data; and an extra adaptation stage using a full-variance transform. Overall these changes to the system reduced the error rate by 13% on the 1997 evaluation data and the final system had an overall word error rate of 13.8% for the 1998 evaluation data sets. 1. Introduction Significant progress in the accurate transcription of broadcast news data has been made over the last few years so that we are now at a point where such systems can be used for a variety of tasks such as audio indexing and retrieval. However there is still much interest in re...