CTIMIT: a speech corpus for the cellular environment with applications to automatic speech recognition

This paper reports on techniques used in the generation of a continuous speech, multi-speaker, cellular bandwidth database and describes its application to automatic speech recognition in the cellular environment. CTIMIT (cellular TIMIT) has been generated by transmitting the TIMIT speech database over the cellular network. The CTIMIT database can have widespread applicability in the design and development of speech processing and speech recognition products for the cellular market. It describes the preliminary collection of the CTIMIT database and reports on several studies designed to test the utility of the database in a phoneme recognition task. Two HMM-based phoneme recognizers were trained using utterances drawn from the TIMIT database and the CTIMIT database, respectively. Each recognizer was then tested using the test utterances from CTIMIT. Phoneme recognition accuracy for the TIMIT-trained recognizer dropped 58% from its baseline performance on TIMIT test utterances. By comparison, phoneme recognition accuracy of the CTIMIT-trained recognizer increased 82% compared to that of the TIMIT-trained recognizer