A new approach has been proposed for increasing astronaut comfort and speech capture. Currently, the special design of a spacesuit forms an extreme acoustic environment making it difficult to capture clear speech without compromising comfort. The current system, called Communication-Cap-based Audio (CCA), relies on a single microphone placed close to the subject’s mouth. While this results in clear audio, it also has problems: wire fatigue, blind mating, interference with food/drink, need for custom communication caps, and not being able to adjust the microphone during extravehicular activities.
The proposed Integrated Spacesuit Audio (ISA) system is to incorporate the microphones into the helmet and use software to extract voice signals from background noise. The system would rely on an array of microphones to enhance speech quality. It will feature performance similar to the CCA system while providing comfort, ease of use, and logistical convenience. In this study, the feasibility of using microphone array beam forming or multichannel noise reduction plus a single-channel post-filter to combat a variety of in-helmet noise was validated.
The developed multichannel plus single-channel noise reduction approach can effectively enhance the intelligibility or quality of the speech from the subject. Using the acoustic data recorded inside spacesuits, it was shown that the developed multichannel noise reduction algorithm can help improve the signal-to-noise ratio (SNR) by approximately 20 dB in ideal cases, and 8–12 dB in worst cases. With four microphones, the multichannel noise reduction algorithm can yield a 4–5 dB gain in SNR with no distortion, and 12–15 dB SNR with a moderate amount of speech distortion. This new approach is more practical and more advantageous than the traditional microphone array beam-forming solutions.
This system would be applicable not only for spaceflight, but also for telecollaboration, human-machine interface, hands-free in-car phone interface, acoustic surveillance, and any kind of system where wide-area sound sensing is important.
This work was done by Yiteng (Arden) Huang, Jingdong Chen, and Shaoyan (Sharyl) Chen of WeVoice, Inc. for Glenn Research Center.
Inquiries concerning rights for the commercial use of this invention should be addressed to NASA Glenn Research Center, Innovative Partnerships Office, Attn: Steve Fedor, Mail Stop 4–8, 21000 Brookpark Road, Cleveland, Ohio 44135. Refer to LEW-18405-1.