Abstract: A system is provided for imaging an underwater environment. The system includes one or more arrays of transducer elements. Each array is operated at a fixed phase shift and varies in frequency so as to beamform multiple sonar return beams of a first range of angles and a second range of angles. The arrays can be oriented to cover the gap in sonar coverage for other arrays to create a continuous arc of sonar coverage. Accordingly, a 2D live sonar image can be formed. Three arrays are mounted in a housing in an X plus Line configuration with one of the arrays extending below the center of the X.

Abstract: A light detection and ranging system. The system includes a solid-state optical antenna array, a phase monitor array, a phase controller, a plurality of phase shifters and a global phase shifter. The phase monitor array is configured to output a first mixed signal associated with one of the optical antenna subarrays, and a second mixed signal associated with two of the optical antenna subarrays. The phase controller is configured to output a first phase coefficient based on the first mixed signal and a second phase coefficient based on the second mixed signal. One of the phase shifters is configured to apply the first phase coefficient to compensate for temperature variation within one of the optical antenna subarrays. The global phase shifter is configured to apply the second phase coefficient to compensate for temperature variation between two of the optical antenna subarrays.

Abstract: A digital transmit beamformer for an ultrasound system has a waveform sample memory which stores sequences of samples of different pulse transmit waveforms of differing pulse widths. The memory is shared by a plurality of transmit channels, each of which can access its own selected sample sequence, independent of the selections by other channels. Waveform sample readout by the channels occurs substantially simultaneously during a transmit event, producing a transmit beam from a transmit aperture with different pulse waveforms applied to different elements of the transmit aperture. Higher energy waveforms with wider pulse widths are applied to central elements of the aperture and lower energy waveforms with narrower pulse widths are applied to lateral elements of the aperture to produce an apodized transmit beam.

Abstract: A distance measuring device is disclosed that includes a controller operably coupled with a receiver to receive different amplification channels. The controller includes a time of flight core configured to determine time of flight information for the light pulse; and a decider block configured to determine a measurement correction value for the device based on a determination of a presence of a reflective background that is different than a measurement correction value selected for the device when there exists a diffuse background or an absence of a background into a reading field.

Abstract: A positioning system comprising a processing system (7; 9) configured to receive a first position estimate for a mobile device (7), and to receive data representative of an acoustic signal received by the mobile device (7) from one of a plurality of acoustic transmitter units (2, 3, 4, 5). For each of the acoustic transmitter units (2, 3, 4, 5), the processing system (7; 9) determines spatial likelihood data representative of a likelihood of the received acoustic signal having been transmitted by the respective acoustic transmitter unit by comparing a time-of-flight range value with a geometric distance value, representative of a distance between the acoustic transmitter unit and the first position estimate.

Abstract: Determining locations to gather information to reduce the number of locations without reducing the information gathered is of key importance when such observations require drilling or other resource-intensive activities. By utilizing ergodic sampling, the same information (volume and/or resolution) may be obtained when compared to an exhaustive grid approach but with significantly fewer observations.

Abstract: A system for evaluation of a sheathing behind a casing of a wellbore. One or more wave generators provide at least asymmetric lamb (AL) waves through a casing having an anisotropic property in a first mode of the system, and provide at least shear horizontal acoustic (SHA) waves through the casing in a second mode that is concurrent with the first mode. A receiver receives indications associated with the SHA waves and the AL waves. At least one processor determines a quality of the sheathing behind the casing based in part on the indications associated with the SHA waves and the AL waves.

Abstract: A sensor assembly includes a base, a housing mounted to the base and rotatable relative to the base around an axis in a direction of rotation, a sensing apparatus inside the housing and rotatable with the housing, and a sensor window extending from a point on the housing in a direction that is radially outward and circumferential relative to the axis. The sensor window is flat. The sensing apparatus has a field of view through the sensor window. An exterior surface of the sensor window faces in a direction that is radially outward and circumferentially in the direction of rotation relative to the axis.

Abstract: A time-of-flight based distance measuring method and a time-of-flight based distance measuring system are provided. The distance measuring method includes: sending N consecutive pulses from a transmitter side intermittently, N being a positive integer greater than one, wherein the N consecutive pulses are reflected by a target object, and a reflection signal is generated accordingly, during arrival of the reflected signal at a receiver side, sampling the reflected signal multiple times according to a predetermined sampling interval within a predetermined sampling duration and accordingly generating a sampling result; detecting time of flight of a single pulse of the N consecutive pulses traveling from the transmitter side to the receiver side according to the sampling result; and measuring a distance between the target object and a reference position according to the time of flight. The distance measuring method maintains good measurement quality, measures the distance rapidly, and consumes low power.

Abstract: System and techniques to position a first source array at a fixed first inline distance from a vessel, position a second source array at a fixed second inline distance from a vessel, wherein the fixed second horizontal inline distance differs from the fixed first horizontal distance, generating a spatial coding, fire the first source array, and fire the second source array.

Abstract: The present disclosure relates to a method of simultaneous manufacturing, from a same substrate (101), at least one first CMUT transducer (I) having a first resonance frequency and at least one second CMUT transducer (II) having a second resonance frequency different from the first frequency, the method comprising the steps of: a) for each transducer (I, II), forming a cavity (103) on the upper surface side of the substrate, and forming a flexible membrane (105) suspended above the cavity (103); b) forming a first layer (109) extending over a portion only of the upper surface of the membrane (105) of the first transducer (I) and which does not extend over the membrane (105) of the second transducer (II); and c) forming a second layer (111) extending over the entire upper surface of the membrane (105) of the first transducer and over the entire upper surface of the membrane of the second transducer.

Abstract: In a method for multipath reflection correction of acoustic signals received at an ultrasonic sensor, acoustic signals are received at the ultrasonic sensor over a time of flight range. Characteristics of multipath reflection signals of received acoustic signals are determined, wherein the characteristics of the multipath reflection signals of the received acoustic signals comprise a relationship of primary signal contributions to multipath reflection signal contributions for the acoustic signals received at the ultrasonic sensor at a plurality of times of flight for a plurality of locations of the ultrasonic sensor. The characteristics of the multipath reflection signals of received acoustic signals are compared to the received acoustic signals.

Abstract: An ultrasonic transducer is described. The ultrasonic transducer comprises a membrane and a substrate disposed opposite the membrane such that a cavity is formed therebetween. The substrate comprises an electrode region and pedestals protruding from a surface of the substrate and having a height greater than a height of the electrode region, the pedestals being electrically isolated from the electrode region.

Abstract: An acoustic transmission device may communicate sensing data via one or more multiple-input multiple-output (MIMO) transmissions. The device may comprise a serial peripheral interface (SPI) and/or a phase shifting key (PSK) modulator. The device may be configured to provide a first SPI signal, perhaps including one or more coded information bits, to the PSK modulator. The device may provide a second SPI signal, perhaps including a synchronous clock signal, to the PSK modulator. The device may generate of one or more symbols on N transmit branches based on the first SPI signal. The device may generate of at least one carrier frequency with one or more phases to form one or more phased carriers based on the second SPI signal. The device may control a transmission of the sensing data (e.g., video) via the one or more symbols on the N transmit branches on the one or more phased carriers.

Abstract: Techniques, systems, and devices are disclosed for spatial and temporal encoding of transmission in full synthetic transmit aperture imaging to achieve optimal spatial and contrast resolution and large signal-to-noise ratio for medical imaging applications with fewer signal transmissions, which can be equal to or less than the number of array elements within the aperture. In some aspects, a method of signal transmission is disclosed that includes a sequence of one or more sets of transmissions on a plurality of elements with unique, random, and/or optimized combinations of waveforms using amplitude and phase, and/or delay encoding. Sets of echoes corresponding to the sequence are beamformed such that fewer transmissions are needed than the number of array elements within the aperture, while maintaining complete spatial sampling of the aperture as if sampled according to a full set of synthetic transmit aperture transmissions on the same aperture.

Abstract: A reflective sonar imaging system is provided. The system includes a reflective sonar imaging assembly. The reflective sonar imaging assembly includes a receiving aperture, a reflective surface defining a concave shape, and a receiver positioned between the reflective surface and the receiving aperture. The system also includes a display and processing circuitry. The reflective surface is configured to cause sonar returns to be reflected as reflected sonar returns toward the receiver. The sonar returns enter the reflective sonar imaging assembly through the receiving aperture, and the receiver is configured to receive the reflected sonar returns. The receiver is configured to generate sonar return data using the reflected sonar returns that are received, and the processing circuitry is configured to receive the sonar return data and generate one or more sonar images based on the sonar return data. The display is configured to present the sonar image(s).

Abstract: A geofenced autonomous aquatic drone for repelling sharks from a shoreline. The drone employs a buoyant housing resembling a portion of a predator such as an orca whale. A battery positioned within the drone is recharged through a floating inductive charging station. A transmitter unit coupled to at least one under water transducer introduces certain sounds, such as reproduction of orca whale or dolphin calling sounds. A propulsion system controlled a microprocessor receives location information via DGPS for providing a geofence around an area to be patrolled. The drone travels within the geofence area, monitored by the DGPS receiver, while said transducer produces certain sounds and or a solution of shark repellant is dispensed.

Abstract: Provided are an ultrasonic imaging method and device, and a storage medium. The ultrasonic imaging method includes: acquiring an ultrasonic echo signal; segmenting the ultrasonic echo signal into a first predetermined number of sub-echo signals according to scan depths; performing amplitude apodization on each sub-echo signal with a predetermined window function to obtain processed sub-echo signals; completing ultrasonic imaging according to the processed sub-echo signals.

Abstract: A synthetic aperture sonar (SAS) system utilizes a novel timing and pointing method to illuminate and process data from multiple receive channels over one or more elevation swaths. The system further utilizes cross-track interferometry to improve accuracy of three-dimensional mapping.

Abstract: Systems, methods, and other embodiments associated with acoustic fingerprint identification of devices are described. In one embodiment, a method includes generating a target acoustic fingerprint from acoustic output of a target device. A similarity metric is generated that quantifies similarity of the target acoustic fingerprint to a reference acoustic fingerprint of a reference device. The similarity metric is compared to a threshold. In response to a first comparison result of the comparing of the similarity metric to the threshold, the target device is indicated to match the reference device. In response to a second comparison result of the comparing of the similarity metric to the threshold, it is indicated that the target device does not match the reference device.