PROBLEM TO BE SOLVED: To highly accurately detect the minute displacement of a target object to be detected after eliminating the effect of vibration propagated from the place of installation.SOLUTION: A sensor unit 10 for sending an ultrasonic wave, i.e., a transmitted wave, to a human body present in an observation space, receiving its reflected wave by a microphone 102 and detecting the motion (displacement) of a chest due to the aspiration of the human body includes a transmit/receive wave control unit 109 for delaying or advancing the D/A conversion by a D/A converter 104 of an ultrasonic wave sent from a speaker 101 and the A/D conversion by an A/D converter 107 of the reflected wave received by the microphone 102 on the basis of a transmitted wave lag time or a reflected wave lag time calculated from the vibration amount inputted from a vibration amount measurement unit 108 in order to eliminate a lag time due to the vibration amount.SELECTED DRAWING: Figure 2COPYRIGHT: (C)2020,JPO&INPIT【課題】設置箇所から伝わる振動の影響を排除して検出したい対象物体の微小な変位を高精度に検出すること。【解決手段】観察空間内に存在する人体に送信波である超音波を送波し、その反射波をマイク１０２で受波して人体の呼吸に伴う胸郭の動き（変位）を検出するセンサユニット１０は、振動量計測部１０８から入力した振動量から算出した送信波ずれ時間又は反射波ずれ時間に基づいて、スピーカー１０１から送波する超音波のＤ／Ａ変換部１０４によるＤ／Ａ変換動作と、マイク１０２で受波する反射波のＡ／Ｄ変換部１０７によるＡ／Ｄ変換動作を、振動量によるずれ時間を排除されるように遅らせたり進ませたりする送受波制御部１０９を備えている。【選択図】図２
