Using word confidence score, insertion and substitution thresholds for selected words in speech recognition

摘要

A method and system for improving the accuracy of a speech recognition system using were confidence score (WCS) processing is introduced. Parameters in a decoder are selected to minimize a weighted total error rate, such that deletion errors are weighted more heavily than substitution and insertion errors. The occurrence distribution in WCS is different depending on whether the word was correctly identified and based on the type of error. This is used to determine thresholds in WCS for insertion and substitution errors. By processing the hypothetical word (HYP) (output of the decoder), a mHYP (modified HYP) is determined. In some circumstances, depending on the WCS's value in relation to insertion and substitution threshold values, mHYP is set equal to: null, a substituted HYP, or HYP.

主权项

1. A method for recognizing speech in acoustic data, comprising:
developing a selected word list; determining an insertion threshold value for each word on the selected word list; determining a substitution threshold value for each word on the selected word list; conducting a tuning phase on each word to provide an occurrence distribution in WCS for such situations as: word is correctly identified, word is substituted, and word is inserted; generating at least one hypothetical word (HYP) in a decoder; deriving a word confidence score (WCS) for each HYP; and determining a modified hypothetical word (mHYP) for each HYP based on the HYP and the WCS for each HYP; wherein the insertion and substitution threshold values are based at least in part on WCS occurrence distributions.