A Vibration Control Method of an Electrolarynx Based on Statistical <i>F</i>₀ Pattern Prediction

Abstract

SUMMARY This paper presents a novel speaking aid system to help laryngectomees produce more naturally sounding electrolaryngeal (EL) speech. An electrolarynx is an external device to generate excitation signals, instead of vibration of the vocal folds. Although the conventional EL speech is quite intelligible, its naturalness suffers from the unnatural fundamental frequency (F 0 ) patterns of the mechanically generated excitation signals. To improve the naturalness of EL speech, we have proposed EL speech enhancement methods using statistical F 0 pattern prediction. In these methods, the original EL speech recorded by a microphone is presented from a loudspeaker after performing the speech enhancement. These methods are effective for some situation, such as telecommunication, but it is not suitable for face-to-face conversation because not only the enhanced EL speech but also the original EL speech is presented to listeners. In this paper, to develop an EL speech enhancement also effective for face-to-face conversation, we propose a method for directly controlling F 0 patterns of the excitation signals to be generated from the electrolarynx using the statistical F 0 prediction. To get an "actual feel" of the proposed system, we also implement a prototype system. By using the prototype system, we find latency issues caused by a real-time processing. To address these latency issues, we furthermore propose segmental continuous F 0 pattern modeling and forthcoming F 0 pattern modeling. With evaluations through simulation, we demonstrate that our proposed system is capable of effectively addressing the issues of latency and those of electrolarynx in term of the naturalness.

Design of Electrolarynx to Increase Energy Efficiency by Varying the Driving Source

“…Control electronics designed using the electromyography activity of the neck muscles (Arifin et al, 2014;Fuchs et al, 2015;Oe et al, 2017) and video cameras to capture lip movement (Wu et al, 2013) provide an automatic control over the electrolarynx. A statistical method for varying fundamental frequencies suggests that, this allows for more natural speech (Tanaka et al, 2016;Tanaka et al, 2017). Based on the electrolarynx speech signals' feedback, the excitation signal is varied to accommodate differences in fundamental frequency.…”