Yoshihisa Nakatoh

Detecting system of approaching vehicles using an ultrasonic wave

The elderly population is increasing, and the traffic environment surrounding elderly people is not safe. We can prevent traffic accidents at an early stage by jumping out of the way if we perceive that the approaching vehicle may collide with the walking elderly person. Therefore, we think that it would be useful if we could build a system to inform us of the approaching vehicle by a supersonic wave. In this paper, using a supersonic wave loudspeaker attached to a vehicle, we proposed the technique to detect approaching vehicles on the sidewalk. We found that we could detect areas around 50 m with a high probability of more than 80% by using a tone burst as input to the supersonic wave loudspeaker.

Preliminary Study of Mobile Device-Based Speech Enhancement System Using Lip-Reading

This paper describes our preliminary study towards a new type of speech enhancement system. To avoid using odd-looking electrolarynx, we used lip-reading function. Our final image is to use a smart phone with camera and audio output to be able to convert the lip motion to speech output. We tested MLP, CNN, and MobileNets image recognition methods. 3k image datasets for training and testing were recorded from five persons. The preliminary experiment indicated that the MobileNets is the most adequate algorithm for smart phone apps. in terms of the recognition accuracy and the calculation cost.

Development of Hands-free Speech Enhancement System for Both EL-users and Esophageal Speech Users

A hands-free speech enhancement system for laryngectomies is proposed to improve the usability and the speech quality. The system has a small and right weight transducer, photo-reflector based lip movement level sensors, and a microphone. The sensor outputs are used for generating the transducer turn on/off signal. A simple performance test was conducted if the system can determine the utterance segments accurately, and the result showed good utterance detection performance. Also, we tested with five more subjects and confirmed that the proposed method was well performed even under the speaker-independent condition.

Study on the Improvement of Intelligibility for Elderly Speech Using Formant Frequency Shift Method

In general, aging is progressing in developed countries. Elderly people have difficulty controlling their articulation accurately due to aging. We need to improve the quality of elderly speech for smooth communication. In this paper, we analyzed the 1st formant frequency (F1) and 2nd formant frequency (F2) between the more intelligible speech and less intelligible speech of Japanese elderly people. In addition, we improved the intelligibility of less intelligible elderly speech by using the formant frequency shift method. This method is the correcting by shift value of formant frequency based on LPC. The shift value is the magnification such as expanding the F1-F2 size of less intelligible speech.

Design of elder-friendly auditory signals for microwave ovens

Recent house electrical appliances generate a number of auditory signals, when a user operates an appliance or an appliance draws attention to a user. In this paper, we focus on multi-functional microwave ovens, which commonly have several auditory signals for users operation, error occurrence, completion of cooking, and so on. A wide variety of auditory signals for current microwave ovens have two problems: it is difficult for users to image what the auditory signals inform, and the auditory signals including high frequency components are not friendly for elderly users. In this paper, popular auditory signals for microwave ovens were subjectively evaluated with/without an elderly-simulated band-pass filter, which simulated an averaged audiogram of elder people, on the five grade scales of easiness of perception, unpleasantness, and emergency. Experimental results suggest that young and elderly people might imagine different function for a single auditory signal. Finally, suitable auditory signals both for young and elderly users are proposed in the viewpoints of frequency and temporal patterns.