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.

Techniques are described herein for displacing liquid away from a signal path of sonic signals in a signal anemometer. A sonic anemometer may include a membrane positioned between a sonic transducer and the open environment. The membrane may be formed of a hydrophobic material that repels the liquid. The membrane may also include a plurality of pores that impede the flow of liquid through the membrane but enables sonic signals to pass through the membrane. The sonic anemometer may also include a reflector that displaces liquid away from the signal path of the sonic anemometer. The reflector may include one or more pores that wick liquid away from the signal path.

Techniques are described herein for displacing liquid away from a signal path of sonic signals in a signal anemometer. A sonic anemometer may include a membrane positioned between a sonic transducer and the open environment. The membrane may be formed of a hydrophobic material that repels the liquid. The membrane may also include a plurality of pores that impede the flow of liquid through the membrane but enables sonic signals to pass through the membrane. The sonic anemometer may also include a reflector that displaces liquid away from the signal path of the sonic anemometer. The reflector may include one or more pores that wick liquid away from the signal path.

A wind speed specification system according to the present disclosure includes an optical fiber (10) laid around a power transmission line (40), a reception unit (20) that receives an optical signal including information indicating a sound generated when an airflow hits the optical fiber (10), from the optical fiber (10), and a specification unit (32) that specifies a wind speed around the optical fiber (10), based on information indicating a sound that is included in the optical signal.

An acoustic dual-frequency phased array system with common beam angles is disclosed. In one aspect, the system includes a planar array of transducer elements and a multiplexing circuit for selecting between a first state and a second state during either transmit operation, receive operation or both transmit and receive operation. The multiplexer is configured to connect transducer elements to a plurality of connections different between the first state and second state. The system is configured to transmit and receive beams at a first frequency when the multiplexer is in the first state and transmit and receive beams at a second frequency when the multiplexer is in the second state. The angle of the beams from vertical in the first and second state are substantially similar.

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 autonomous vehicle includes audio sensors configured to detect audio in an environment around the autonomous vehicle and to generate audio signals based on the detected audio. A processor in the autonomous vehicle receives the audio signals and compares a time domain or frequency domain representation of the audio signals to a corresponding representation of a known emergency vehicle siren. The comparison causes the processor to output a first determination indicating whether the audio signals are indicative of an emergency vehicle siren. The processor also applies a trained neural network to the audio signals that causes the processor to output a second determination indicating whether the audio signals are indicative of the emergency vehicle siren. If the first determination or the second determination indicates presence of an emergency vehicle siren in the environment around the autonomous vehicle, the autonomous vehicle is caused to perform an action.

A system and method for enhancing visualization of color flow ultrasound is provided. The method includes generating estimated parameter values from filtered ultrasound image data. The method includes applying filter thresholds to the estimated parameter values, wherein the filter thresholds comprise first and second high power rejection thresholds and first and second low power and low velocity rejection thresholds. The method includes applying a transparency map to the estimated parameter values between the first and second high power rejection thresholds and between the first and second low power and low velocity rejection thresholds. The method includes generating a color flow image based at least in part on the estimated parameter values. The method includes presenting the color flow image at a display system.

An acoustic vector sensor has an array of sensors to detect at least the bearing of a target. The acoustic vector sensor or hydrophone with sensor array avoids the need to deploy multiple hydrophones each with a single sensor. The array of sensor signals can be processed using any one of a number of methods.

A Doppler device including a transducer and processing circuitry is provided. The transducer transmits underwater ultrasonic wave and receives a reflected wave of the ultrasonic wave. The Doppler device generates a first echo signal from the reflected wave in a first direction making a depression angle θ with a receiving surface of the transducer, generates a second echo signal from the reflected wave in a second direction making the depression angle θ with the receiving surface, the second direction being different from the first direction, and generates a third echo signal in a third direction perpendicular to the receiving surface. The processing circuitry further calculates a first Doppler frequency of the first echo signal, a second Doppler frequency of the second echo signal, and a third Doppler frequency of the third echo signal. The processing circuitry further calculates the depression angle θ from the first, second and third Doppler frequencies.