Improvement of Abnormality Detection System for Bathers Using Ultrasonic Sensors.

This paper proposes a new method for improving an existing abnormality detection system for a person who soaks in a bathtub. As the number of aged people increases year by year in Japan, bathing accidents among the aged are growing at a rapid rate, especially in-bathtub drowning accidents. Therefore, prompt detection of a bather's abnormality, such as dizziness and fainting, is important to prevent in-bathtub drowning. In order to detect a bather's abnormality promptly, an abnormality detection system using seven ultrasonic sensors has been proposed. The system uses two methods-posture detection and motion detection-to detect a difference in a bather's state compared to normal before an accident occurs, and improves the delay in detection considered heretofore to be a serious problem. There was, however, plenty of room for improvement. In order to improve the detection rate of the system, we propose a new detection method in this paper. The method uses two ultrasonic sensors to scan a bather's head and neck, and detects the head height and swing speed of the head. Experimental results are superior to the accuracy of the existing system, which enables us to detect an abnormality in a bather more precisely. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 179(3): 57-67, 2012; Published online in Wiley Online Library (). DOI 10.1002/eej.21133 [ABSTRACT FROM AUTHOR]