The principal aim of this paper is to present a novel speech transmission system that conveys speech between an actuator in a wearable wristwatch and the ear bone of a user through a finger. If an individual wears a smart watch equipped with an actuator that can play speech sent via communication lines, speech vibrations propagate from the actuator to fingertips through the human tissue and bone. When an individual places his or her finger into their ear, speech conducted through the finger can be registered and heard. While listening to finger-conducted speech, sounds are muffled, significantly degrading the intelligibility of speech. To mitigate this problem, a formant enhancement filter is applied to the speech prior to being fed into the actuator. With this method, the impulse response of human tissue and bones between the fingertips and wrist on which the watch is worn is first estimated to account for speaker-dependent distortion. Based on the estimated impulse response, a gain filter is used to boost the sound spectra, especially within the formant regions, to compensate for frequency distortion prior to speech transmission. On the other hand, since the impulse responses of humans are quite different for each individual, we propose the novel idea of a personalized algorithm that guides users to select an appropriate gain filter, using the k-medoids clustering algorithm. Also, when an individual uses the proposed system, speech quality is degraded due to the ambient noise and acoustic echo between the microphone and actuator in the watch. Thus, to reduce background noise and acoustic echo, an integrated acoustic echo and background noise suppression algorithm is employed. Extensive simulations of the proposed system were performed by creating a novel phantom, which mimics the human hand with an aid of an ear simulator. We demonstrate that the proposed system has improved speech quality, when transmitting speech from the wearable wristwatch to a human perceptual organ through the finger.

中文翻译：

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采用手指传导语音传输系统的智能手表


本文的主要目的是提出一种新颖的语音传输系统，该系统通过手指在可穿戴手表的执行器和用户的耳骨之间传输语音。如果一个人佩戴的智能手表配备了可以播放通过通信线路发送的语音的执行器，那么语音振动就会从执行器通过人体组织和骨骼传播到指尖。当一个人将他或她的手指放入耳朵时，可以记录并听到通过手指进行的语音。在聆听手指传导的语音时，声音会变得低沉，从而显着降低语音的清晰度。为了缓解这个问题，在将语音馈送到执行器之前，对语音应用共振峰增强滤波器。通过这种方法，首先估计佩戴手表的指尖和手腕之间的人体组织和骨骼的脉冲响应，以考虑与扬声器相关的失真。根据估计的脉冲响应，增益滤波器用于增强声谱，特别是在共振峰区域内，以补偿语音传输之前的频率失真。另一方面，由于每个人的脉冲响应差异很大，我们提出了个性化算法的新颖想法，使用 k-medoids 聚类算法指导用户选择合适的增益滤波器。此外，当个人使用所提出的系统时，由于环境噪声以及手表中的麦克风和执行器之间的声学​​回声，语音质量会下降。因此，为了减少背景噪声和声学回声，采用了集成的声学回声和背景噪声抑制算法。 通过创建一种新颖的模型来对所提出的系统进行广泛的模拟，该模型在耳朵模拟器的帮助下模仿人手。我们证明，当通过手指将语音从可穿戴手表传输到人类感知器官时，所提出的系统提高了语音质量。