INTERSPEECH 2008
9th Annual Conference of the International Speech Communication Association

Brisbane, Australia
September 22-26, 2008

On Estimation of a Speaker's Confusion Matrix from Sparse Data

Stephen Cox

University of East Anglia, UK

Confusion matrices have been widely used to increase the accuracy of speech recognisers, but usually a mean confusion matrix, averaged over many speakers, is used. However, analysis shows that confusion matrices for individual speakers vary considerably, and so there is benefit in obtaining estimates of confusion matrices for individual speakers. Unfortunately, there is rarely enough data to make reliable estimates. We present a technique for estimating the elements of a speaker's confusion matrix given only sparse data from the speaker. It utilizes non-negative matrix factorisation to find structure within confusion matrices, and this structure is exploited to make improved estimates. Results show that under certain conditions, this technique can give estimates that are as good as those obtained with twice the number of utterances available from the speaker.

Full Paper

Bibliographic reference.  Cox, Stephen (2008): "On estimation of a speaker's confusion matrix from sparse data", In INTERSPEECH-2008, 2618-2621.