Robustness issues and solutions in speech recognition based telephony services

HMM-based algorithms for speaker-dependent recognition as well as speaker-independent recognition form the basis of speech services developed at Nynex S&T and deployed widely by Nynex and other telephone service providers. Based on the analysis of the initially deployed VoiceDialing service, the robustness of these algorithms was recognized to be a dominant issue. We discuss the features of a high-performance, robust speaker-dependent recognition algorithm, and include some deployment issues that were successfully resolved.