An ultrasonic-based person detection method. The method comprising the steps of: (a) emitting, from an emitter, an ultrasonic signal, the ultrasonic signal including a component at a first frequency; (b) receiving reflections of the ultrasonic signal, the received signal including components at frequencies greater than and less than the first frequency; (c) determining a difference between an upper portion of the received signal containing a frequency higher than the first frequency, and a lower portion of the received signal containing a frequency lower than the first frequency; and (d) determining, based on the difference between the upper portion and the lower portion, whether a person is present.

In order to estimate the trajectory of a moving wave source, this trajectory estimation device (10) comprises: an acquisition unit (11) that acquires wave motion data based on wave motion detected by a plurality of sensors (100); a generation unit (12) that generates a spectrogram using the wave motion data; an extraction unit (13) that extracts a Doppler shift from the spectrogram; a selection unit (14) that selects, as a sensor pair, two sensors that satisfy a preset selection condition pertaining to the Doppler shift; and an estimation unit (15) that estimates the trajectory of a wave source, which is the source generating the wave motion, on the basis of the positional relationship between the sensors constituting the sensor pair and the relationship of the Doppler shift between the two sensors constituting the sensor pair.

In order to estimate the trajectory of a moving wave source, this trajectory estimation device (10) comprises: an acquisition unit (11) that acquires wave motion data based on wave motion detected by a plurality of sensors (100); a generation unit (12) that generates a spectrogram using the wave motion data; an extraction unit (13) that extracts a Doppler shift from the spectrogram; a selection unit (14) that selects, as a sensor pair, two sensors that satisfy a preset selection condition pertaining to the Doppler shift; and an estimation unit (15) that estimates the trajectory of a wave source, which is the source generating the wave motion, on the basis of the positional relationship between the sensors constituting the sensor pair and the relationship of the Doppler shift between the two sensors constituting the sensor pair.

Proposed is a noise avoiding method for a space monitoring apparatus using a sound signal and, more specifically, is a technology that allows the space monitoring apparatus, which uses a sound signal to monitor a spatial condition, to avoid noise in a space to be monitored to correctly determine the spatial condition.

Proposed is a noise avoiding method for a space monitoring apparatus using a sound signal and, more specifically, is a technology that allows the space monitoring apparatus, which uses a sound signal to monitor a spatial condition, to avoid noise in a space to be monitored to correctly determine the spatial condition.

In an ultrasonic detection system that uses frequency-modulation coding to distinguish emitted bursts from multiple transducers, a receiver associated with a transducer uses dynamic thresholding to discriminate valid echoes from system and environmental noise in multiple envelope signals produced by multiple correlators. The time-varying dynamic thresholds are generated from the mean of noise in a respective envelope derived from the output of a respective correlator. Multiple thresholds can be combined together such that a single time-varying threshold is applied to all correlators' envelopes. Such thresholding has the benefits of a constant false-alarm rate with regard to detection of echoes (as opposed to false triggering from noise), and, owing to finer-resolution and adaptive thresholds, can detect targets or obstacles as further distances and with greater time responsiveness.

In an ultrasonic detection system that uses frequency-modulation coding to distinguish emitted bursts from multiple transducers, a receiver associated with a transducer uses dynamic thresholding to discriminate valid echoes from system and environmental noise in multiple envelope signals produced by multiple correlators. The time-varying dynamic thresholds are generated from the mean of noise in a respective envelope derived from the output of a respective correlator. Multiple thresholds can be combined together such that a single time-varying threshold is applied to all correlators' envelopes. Such thresholding has the benefits of a constant false-alarm rate with regard to detection of echoes (as opposed to false triggering from noise), and, owing to finer-resolution and adaptive thresholds, can detect targets or obstacles as further distances and with greater time responsiveness.

An object detection device includes: a transceiver having a predetermined resonance frequency; a driving signal generation unit generating a driving signal having a driving frequency different from the resonance frequency for driving the transceiver; a filter extracting and outputting at least one received signal from received signals of the transceiver; and a detection determination unit performing object detection determination based on the extracted at least one received signal. The received signals include a first and second received signals, the first received signal having a frequency that has been shifted from the driving frequency to the resonance frequency; and the filter has a characteristic that: when extracting the first received signal, outputs the extracted first received signal as a first output signal, and when extracting the second received signal, outputs the extracted second received signal as a second output signal, the first output signal being greater than the second output signal.

An object detection device includes: a transceiver having a predetermined resonance frequency; a driving signal generation unit generating a driving signal having a driving frequency different from the resonance frequency for driving the transceiver; a filter extracting and outputting at least one received signal from received signals of the transceiver; and a detection determination unit performing object detection determination based on the extracted at least one received signal. The received signals include a first and second received signals, the first received signal having a frequency that has been shifted from the driving frequency to the resonance frequency; and the filter has a characteristic that: when extracting the first received signal, outputs the extracted first received signal as a first output signal, and when extracting the second received signal, outputs the extracted second received signal as a second output signal, the first output signal being greater than the second output signal.

A method and beverage container assembly for determining a level of liquid in a beverage container having a lid removably attached thereto. The beverage container assembly including a sensor configured to measure sound waves in the beverage container assembly. A processor is electronically coupled to the sensor, and to memory provided with executable instructions for causing the processor to determine the level of liquid. The executable instructions, when executed by the processor, cause the processor to receive a sound wave measurement from the sensor, obtain a frequency characteristic of the sound wave measurement, and obtain reference information regarding a set of characteristics of the beverage container assembly. The processor may determine the level of liquid in the beverage container assembly based on the frequency characteristic and the reference information.