Recognition confidence measuring by lexical distance between candidates

A computer readable storage medium storing a program for implementing a recognition confidence measurement method comprising:

• extracting a phoneme string from a feature vector of an input speech signal;
• extracting candidates by matching the extracted phoneme string and phoneme strings of vocabularies registered in a predetermined dictionary;
• estimating a lexical distance between the extracted candidates;
• and
• determining whether the input speech signal is an in-vocabulary, based on the lexical distance.

A recognition confidence measurement system comprising:

• a phoneme string extraction unit extracting a phoneme string from a feature vector of an input speech signal;
• a candidate extraction unit extracting candidates by matching the extracted phoneme string and phoneme strings of vocabularies registered in a predetermined dictionary;
• a distance estimation unit estimating a lexical distance between the extracted candidates;
• and
• a registration determination unit determining whether the input speech signal is an in-vocabulary, based on the lexical distance.

A recognition confidence measurement method comprising:

• extracting candidates by matching a phoneme string of a speech signal and phoneme strings of vocabularies registered in a predetermined dictionary;
• estimating a lexical distance between the extracted candidates;
• and
• determining whether the speech signal is an in-vocabulary, based on the lexical distance.