Abstract: An information processing method is an information processing method that is executed by a computer. The information processing method includes acquiring information based on reflected sound obtained by emitting ultrasound into a space and extracting, from the reflected sound, a reflected wave every cycle of emission of the ultrasound to extract reflected waves; generating time-series information by concatenating vectors based on the reflected waves each extracted every cycle of emission of the ultrasound; determining an action of a person in the space in accordance with an output of a trained model, the output being obtained by inputting the generated time-series information to the trained model, the trained model being configured to output, upon receipt of input of time-series information, a human action associated with the time-series information; and outputting a determination result.

Abstract: An information processing method is to be executed by a computer. The method includes acquiring information indicating a first reflected wave of ultrasound acquired by emitting the ultrasound into a space, calculating a feature based on a difference between a first signal and a second signal, the first signal being based on the reflected wave, the second signal being based on information indicating a second reflected wave acquired at a past time before the first reflected wave, and determining whether a person is present or absent in the space in accordance with the calculated feature.

Abstract: A microphone 1 includes a light source 11 that outputs an optical signal, an optical coupler 12 that demultiplexes and multiplexes the optical signal, a transmission path 13 including an optical fiber 130 that transmits a demultiplexed optical signal demultiplexed by the optical coupler 12 to the optical coupler 12 in mutually opposite directions, a sensor part 14 that is connected to the transmission path 13 and returns the demultiplexed optical signal to be transmitted by the transmission path 13 to the transmission path 13 via a space part 40, and a light receiving element 15 that receives a multiplexed optical signal multiplexed by the optical coupler 12.