An acoustic transponder provides information related to the transponder when the transponder is receiving an acoustic interrogating signal. The transponder includes a power supply, an electronic circuit connected to the power supply, and one or more transducers receiving and emitting the acoustic signal. The electronic circuit includes a sequence generator. The transponder further includes an amplification and modulation unit, an extraction filter, and a suppression filter. The extraction filter is adapted to extract the received acoustic interrogating signal and suppress other signals prior to being input to the amplification and modulation unit which are configured to modulate the received acoustic signal according to a sequence generated by the sequence generator and to amplify the modulated signal. The suppression filter is adapted to suppress the received acoustic interrogating signal from the amplified and modulated signal. The amplified modulated signal is transferred through the one or more transducers of the transponder and/or through other transducer(s).

An object detection apparatus detects an object in a vicinity of a moving body in a state of being mounted to the moving body. The object detection apparatus measures a reverberation frequency that is a frequency of a reverberation signal that is generated in a transceiver that externally transmits a transmission wave that is an ultrasonic wave and receives a reception wave that includes a reflected wave of the transmission wave from the object. object detection apparatus detects the object based on the reception wave. The object detection apparatus sets at least one of a transmission characteristic and a reception characteristic in the transceiver. The object detection apparatus sets at least one of transmission characteristics of the transmission wave and/or sets circuit characteristics in the transceiver. The object detection apparatus reduces at least one of the transmission characteristic and the reception characteristic during measurement of the reverberation frequency.

A distance measurement device includes: a transmission and reception device configured to transmit a transmission wave and receive a reflected wave; a memory; and a hardware processor coupled to the memory. The hardware processor is configured to: detect a reception signal received by the transmission and reception device and obtain a reception waveform indicating a temporal change in an intensity of the reception signal; detect a feature amount of the reflected wave based on the reception waveform; calculate a distance from the distance measurement device to an object, based on the feature amount; and control a detection condition of detection of the feature amount by changing a threshold for detecting the feature amount, based on a change in the feature amount, in a case where the reflected wave arrives during a reverberation period in which reverberation of the transmission wave remains in the transmission and reception device.

A distance measurement device includes: a transmission and reception device configured to transmit a transmission wave and receive a reflected wave; a memory; and a hardware processor coupled to the memory. The hardware processor is configured to: detect a reception signal received by the transmission and reception device and obtain a reception waveform indicating a temporal change in an intensity of the reception signal; detect a feature amount of the reflected wave based on the reception waveform; calculate a distance from the distance measurement device to an object, based on the feature amount; and control a detection condition of detection of the feature amount by changing a threshold for detecting the feature amount, based on a change in the feature amount, in a case where the reflected wave arrives during a reverberation period in which reverberation of the transmission wave remains in the transmission and reception device.

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.

A sonar transmit array (11), comprising: a plurality of transmitters configured to generate an acoustic sonar signal, wherein at least one of the transmitters is a polyvinylidene difluoride, PVDF, piezoelectric device configured to generate at least part of the acoustic sonar signal. Some embodiments, include a receive array (12) and the associated receive array circuitry (14).

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.

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.

A sonar survey system including a multibeam echo sounder using plural transmit projectors and plural receive hydrophones, wherein beams with associated magnitudes are received such that the largest magnitude beam(s) are identified as characterizing beam(s) and data associated with these characterizing beam(s) is used as a compressed characterization of the ensonified space.

A sonar survey system including a multibeam echo sounder using plural transmit projectors and plural receive hydrophones, wherein beams with associated magnitudes are received such that the largest magnitude beam(s) are identified as characterizing beam(s) and data associated with these characterizing beam(s) is used as a compressed characterization of the ensonified space.