caa a22 4500 60620606X CHVBK 20210128101010.0 cr unu---uuuuu 210128e20150401xx s 000 0 eng 10.1007/s00034-014-9904-4 doi (NATIONALLICENCE)springer-10.1007/s00034-014-9904-4 Mouth State Detection From Low-Frequency Ultrasonic Reflection [Elektronische Daten] [Ian McLoughlin, Yan Song] This paper develops, simulates and experimentally evaluates a novel method based on non-contact low frequency (LF) ultrasound which can determine, from airborne reflection, whether the lips of a subject are open or closed. The method is capable of accurately distinguishing between open and closed lip states through the use of a low-complexity detection algorithm, and is highly robust to interfering audible noise. A novel voice activity detector is implemented and evaluated using the proposed method and shown to detect voice activity with high accuracy, even in the presence of high levels of background noise. The lip state detector is evaluated at a number of angles of incidence to the mouth and under various conditions of background noise. The underlying mouth state detection technique relies upon an inaudible LF ultrasonic excitation, generated in front of the face of a user, either reflecting back from their face as a simple echo in the closed mouth state or resonating inside the open mouth and vocal tract, affecting the spectral response of the reflected wave when the mouth is open. The difference between echo and resonance behaviours is used as the basis for automated lip opening detection, which implies determining whether the mouth is open or closed at the lips. Apart from this, potential applications include use in voice generation prosthesis for speech impaired patients, or as a hands-free control for electrolarynx and similar rehabilitation devices. It is also applicable to silent speech interfaces and may have use for speech authentication. Springer Science+Business Media New York, 2014 Lip state detection nationallicence Low frequency ultrasound nationallicence Mouth state detection nationallicence Speech activity detection nationallicence Voice activity detection nationallicence McLoughlin Ian National Engineering Laboratory of Speech and Language Information Processing, The University of Science & Technology of China, 230027, Hefei, Anhui, China aut Song Yan National Engineering Laboratory of Speech and Language Information Processing, The University of Science & Technology of China, 230027, Hefei, Anhui, China aut Circuits, Systems, and Signal Processing Springer US; http://www.springer-ny.com 34/4(2015-04-01), 1279-1304 0278-081X 34:4<1279 2015 34 34 https://doi.org/10.1007/s00034-014-9904-4 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00034-014-9904-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- McLoughlin Ian National Engineering Laboratory of Speech and Language Information Processing, The University of Science & Technology of China, 230027, Hefei, Anhui, China aut NATIONALLICENCE 700 1- Song Yan National Engineering Laboratory of Speech and Language Information Processing, The University of Science & Technology of China, 230027, Hefei, Anhui, China aut NATIONALLICENCE 773 0- Circuits, Systems, and Signal Processing Springer US; http://www.springer-ny.com 34/4(2015-04-01), 1279-1304 0278-081X 34:4<1279 2015 34 34