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Speech Acquisition and Automatic Speech Recognition for Integrated Spacesuit Audio SystemsA voice-command human-machine interface system has been developed for spacesuit extravehicular activity (EVA) missions. A multichannel acoustic signal processing method has been created for distant speech acquisition in noisy and reverberant environments. This technology reduces noise by exploiting differences in the statistical nature of signal (i.e., speech) and noise that exists in the spatial and temporal domains. As a result, the automatic speech recognition (ASR) accuracy can be improved to the level at which crewmembers would find the speech interface useful. The developed speech human/machine interface will enable both crewmember usability and operational efficiency. It can enjoy a fast rate of data/text entry, small overall size, and can be lightweight. In addition, this design will free the hands and eyes of a suited crewmember. The system components and steps include beam forming/multi-channel noise reduction, single-channel noise reduction, speech feature extraction, feature transformation and normalization, feature compression, model adaption, ASR HMM (Hidden Markov Model) training, and ASR decoding. A state-of-the-art phoneme recognizer can obtain an accuracy rate of 65 percent when the training and testing data are free of noise. When it is used in spacesuits, the rate drops to about 33 percent. With the developed microphone array speech-processing technologies, the performance is improved and the phoneme recognition accuracy rate rises to 44 percent. The recognizer can be further improved by combining the microphone array and HMM model adaptation techniques and using speech samples collected from inside spacesuits. In addition, arithmetic complexity models for the major HMMbased ASR components were developed. They can help real-time ASR system designers select proper tasks when in the face of constraints in computational resources.
Document ID
Document Type
Other - NASA Tech Brief
Huang, Yiteng (WeVoice, Inc. Bridgewater, NJ, United States)
Chen, Jingdong (WeVoice, Inc. Bridgewater, NJ, United States)
Chen, Shaoyan (WeVoice, Inc. Bridgewater, NJ, United States)
Date Acquired
August 25, 2013
Publication Date
November 1, 2010
Publication Information
Publication: NASA Tech Briefs, November 2010
Subject Category
Man/System Technology and Life Support
Report/Patent Number
Distribution Limits
Public Use Permitted.

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IDRelationTitle20100039392Analytic PrimaryNASA Tech Briefs, November 2010