Rejection and keyword spotting algorithms for a directory assistance city name recognition application

When isolated word speech recognition devices are deployed in real user applications, they must do more than simply recognize isolated words. Real users often embed target words in a longer utterance, and the words should be recognized as often as possible. Out-of-vocabulary utterances must be rejected. The target application is to recognize the city name query of directory assistance. Within this project, a keyword spotting algorithm has been developed which markedly improves the recognizer´s performance on embedded speech. A rejection algorithm has also been implemented, and several variations on the algorithmic approach are compared with respect to their ability to reject out-of-vocabulary utterances while still accepting in-vocabulary correctly-recognized utterances. The keyword spotting and rejection algorithms are evaluated, and the factors contributing to their success are described