An ultrasonic sensing system includes an ultrasonic receiver configured to receive an ultrasonic signal and a gain-adjustable amplifier operably coupled to the ultrasonic receiver. The gain-adjustable amplifier is configured to amplify the ultrasonic signal according to a variable gain determined based at least in part on a value of a timer that corresponds to a measuring distance.

The present invention provides a system for use in a vehicle for determining an indication of the type of terrain in the vicinity of the vehicle. The system comprises a processor arranged to receive acoustic sensor output data from at least one vehicle-mounted acoustic sensor, the or each acoustic sensor being arranged to receive a reflected signal from the terrain in the vicinity of the vehicle, the processor also being arranged to calculate at least one acoustic parameter in dependence on the acoustic sensor output data. The system also comprises a data memory arranged to store pre-determined data relating the at least one acoustic parameter to a particular terrain type. The processor is arranged to compare the at least one acoustic parameter with the pre-determined data to determine an indication of the particular terrain type based on the acoustic sensor output data only.

Ultrasonic ranging state management for a UAV is described. A transducer transmits an ultrasonic signal and receives an ultrasonic response thereto using a gain value. A noise floor estimation mechanism determines a noise floor estimate. A state mechanism sets an ultrasonic ranging state used by the transducer to a first ultrasonic ranging state. The transducer transmits an ultrasonic signal and responsively receive an ultrasonic response to the ultrasonic signal using a gain value according to the noise floor estimate. The state mechanism processes the ultrasonic response to determine whether to determine a new noise floor estimate, adjust the gain value used by the transducer, or change the ultrasonic ranging state of the UAV to a second ultrasonic ranging state. The configurations of the first and second ultrasonic ranging states differ as to, for example, power and gain levels used by the transducer to receive ultrasonic responses.

Disclosed is a marine surface drone including: - an on-board multi-beam sonar; - a system for controlling the sonar, configured to command, for a given position of the drone, a plurality of consecutive transmissions of acoustic waves, the control system controlling the sonar transmitters so as to vary the characteristics of the transmitted acoustic waves, from one of the transmissions to the next, and - an acquisition unit configured to determine, from echo signals acquired in response to the plurality of transmissions, a three-dimensional image representing the content of a given observation volume. The invention also relates to a method for characterising an underwear environment, implemented by such a drone.

This disclosure describes presence-detection devices that detect movement of a person in an environment by emitting ultrasonic signals into the environment, and characterizing the change in the frequency, or the Doppler shift, of the reflections of the ultrasonic signals off the person caused by the movement of the person. In addition to detecting movement, and thus presence of a person, the presence-detection devices may include a microphone array to perform techniques for identifying a direction of movement of the person, and also to perform techniques for identifying a number of people that are in the room. Additionally, the techniques described herein include processing audio signals in such a way to allow for the use of on-board loudspeakers to transmit ultrasonic signals at out-of-band frequencies.

An object detection apparatus includes a transmitting portion configured to transmit a transmission wave, a receiving portion configured to receive a reception wave based on the transmission wave which returned, an estimation portion configured to estimate an amount of frequency transition between the transmission wave and the reception wave on the basis of a result of a frequency analysis, a correction portion configured to correct the reception wave to obtain consistency of frequencies with the transmission wave on the basis of an estimation result of the estimation portion, and a detection portion configured to detect information related to the object on the basis of a relation between the transmission wave and the corrected reception wave corrected by the correction portion.

A method of operating electro-acoustical transducers such as PMUTs involves applying to the transducer an excitation signal over an excitation interval, acquiring at the transducer a ring-down signal indicative of the ring-down behavior of the transducer after the end of the excitation interval, and calculating, as a function of said ring-down signal, a resonance frequency of the electro-acoustical transducer. A bias voltage of the electro-acoustical transducer can be controlled as a function of the resonance frequency. An acoustical signal received can be transduced into an electrical reception signal and a damping parameter of the electro-acoustical transducer can be calculated as a function of the ring-down signal so that a cross-correlation reference signal can be synthesized as a function of the resonance frequency and the damping ratio of the electro-acoustical transducer. Such a cross-correlation reference signal can be used for cross-correlation with the electrical reception signal to improve the reception quality.

A processor is configured to include a correlation object determination unit for establishing: a first to-be-correlated signal established on the basis of a first upper-limit rate of change, which is the rate of change of an upper-limit envelope of a direct wave signal, and a first lower-limit rate of change, which is the rate of change of a lower-limit envelope of the direct wave signal; and a second to-be-correlated signal established on the basis of a second upper-limit rate of change, which is the rate of change of an upper-limit envelope of a round-trip-delayed wave signal, and a second lower-limit rate of change, which is the rate of change of a lower-limit envelope of the round-trip-delayed wave signal. The processor is also configured to include a correlation processing unit for establishing a correlation value between the first to-be-correlated signal and a signal based on the second to-be-correlated signal.

In accordance with some embodiments of the disclosed subject matter, mechanisms (which can, for example, include systems, apparatuses, methods, and media) for determining three dimensional location of an object associated with a person at risk of falling down are provided. In some embodiments, the apparatus comprises: an ultrasound detector; an antenna; and a processor, the processor programmed to: detect a first ultrasound signal at a first time using the ultrasound detector; in response to detecting the first ultrasound signal, cause a first wireless signal to be emitted by the antenna; detect a second ultrasound signal at a second time; in response to detecting the second ultrasound signal, cause a second wireless signal to be emitted by the antenna; determine that a first amount of time has passed since the second ultrasound signal was detected; and in response to determining that the first amount of time has passed since the second ultrasound signal was detected, cause the wearable apparatus to enter a low power state.

A system produces sensed images. The system includes a sensor array, an image display device, and a processor that generates an image illustrating contents of an expanded field of view. The processor receives sensor element data from the sensor array, performs zero padding and discrete Fourier transform to result in a sensor wavenumber data buffer. The processor determines reference point locations, and generates a reference Fresnel field. The processor obtains an inverse Huygens-Fresnel transfer data buffer based on the reference Fresnel field. The processor multiplies each data element of the sensor wavenumber buffer with each corresponding data element of the inverse Huygens-Fresnel transfer data buffer. The processor generates a rectilinear spectrum data buffer based on the multiplication. The processor performs Stolt mapping and uniformly resampling to achieve image data.