High-level approaches to confidence estimation in speech recognition

Abstract--We describe some high-level approaches to estimating confidence scores for the words output by a speech recognizer. By "high-level" we mean that the proposed measures do not rely on decoder specific "side information" and so should find more general applicability than measures that have been developed for specific recognizers. Our main approach is to attempt to decouple the language modeling and acoustic modeling in the recognizer in order to generate independent information from these two sources that can then be used for estimation of confidence. We isolate these two information sources by using a phone recognizer working in parallel with the word recognizer. A set of techniques for estimating confidence measures using the phone recognizer output in conjunction with the word recognizer output is described. The most effective of these techniques is based on the construction of "metamodels," which generate alternative word hypotheses for an utter...

• Type: Journal
• Year: 2002
• Where: TASLP
• Authors: Stephen Cox, Srinandan Dasmahapatra
• Keywords: Phone Recognizer, Recognizers, TASLP 2002, Word Recognizer