| 摘要 |
PROBLEM TO BE SOLVED: To provide technical means capable of subjectively and intuitively recognizing the motion of a detection object.SOLUTION: A transmitter unit 100 of an acoustic motion detection device 1 emits sound of a high range frequency f1 which is almost inaudible for a human being from a speaker 103 toward a detection object. A receiver unit 200 of the acoustic motion detection device 1 acquires reflection sound based on a Doppler shift generated by the motion of the detection object with the use of a microphone 201. The receiver unit 200 multiplies the acquired reflection sound by a sinewave of a frequency f2 in a multiplier 203, so as to shift the frequency of the acquired reflection sound to a frequency of an audible range. The receiver unit 200 removes a component corresponding to high range sound to be emitted by the transmitter unit 100 from the audibly shifted sound with the use of a notch filter 208, and then emits the sound from a speaker 210.SELECTED DRAWING: Figure 1 |
