High-Accuracy Measurement of Small Movement of an Object behind Cloth Using Airborne Ultrasound

概要

論文の詳細を見る
The acoustic measurement of vital information such as breathing and heartbeat in the standing position whilst the subject is wearing clothes is a difficult problem. In this paper, we present the basic experimental results to measure small movement of an object behind cloth. We measured acoustic characteristics of various types of cloth to obtain the transmission loss through cloth. To observe the relationship between measurement error and target speed under a low signal-to-noise ratio (SNR), we tried to measure the movement of an object behind cloth. The target was placed apart from the cloth to separate the target reflection from the cloth reflection. We found that a small movement of less than 6 mm/s could be observed using the M-sequence, moving target indicator (MTI) filter, and tracking phase difference, when the SNR was less than 0 dB. We also present the results of theoretical error analysis in the MTI filter and phase tracking for high-accuracy measurement. Characteristics of the systematic error were clarified.
2013-07-25