Abstract: An apparatus for sensing acoustic energy in a borehole penetrating the earth includes an optical interrogator and a sensing optical fiber having a length Ls optically coupled to the optical interrogator and configured to sense the acoustic energy to provide sensed acoustic data. The apparatus also includes a reference optical fiber having a length Lr optically coupled to the optical interrogator to provide reference data, wherein the optical interrogator corrects the sensed acoustic data using the reference data to provide corrected sensed acoustic data.

Abstract: A time-of-flight imaging device comprises an image sensor comprising a pixel array including a plurality of pixel circuits, respective ones of the plurality of pixel circuits including a first tap output configured to output a first tap signal, and a second tap output configured to output a second tap signal; and a signal processing circuit including a time-of-flight processing circuit configured to perform at least one logical operation on the first tap signal and the second tap signal based on a mode of the signal processing circuit, and a counter configured to output a digital signal based on an output of the time-of-flight processing circuit.

Abstract: What is proposed is a method for optically measuring distances, in the case of which a first plurality of measuring pulses is emitted during a first measuring interval by means of a transmitting element of a transmitting unit at first emitting times, and wherein a second plurality of measuring pulses is emitted during a second measuring interval by means of the transmitting element of the transmitting unit at second emitting times. The method comprises the reception of reflected measuring pulses by means of a receiving element of a receiving unit assigned to the transmitting element at receiving times. The method further comprises the determining of a first amount of times-of-flight for each received measuring pulse, wherein the first amount of times-of-flight is determined by using the first emitting times.

Abstract: An electroacoustic transducer 400 is described. The electroacoustic transducer 400 comprises an active element 410. The electroacoustic transducer 400 comprises an acoustic coupling layer 430 arranged to acoustically couple, in use, the active element 410 to a transmission medium. The electroacoustic transducer 400 further comprises a cavity 420 arranged between the active element 410 and the acoustic coupling layer 430 to receive a fluid. In this way, acoustic coupling of the electroacoustic transducer 400 and the transmission medium is improved.

Abstract: A method of generating ultrasound by driving an array of ultrasonic transducers comprises a charge transfer procedure. The charge transfer procedure comprises switching a terminal of a first ultrasonic transducer of the array, at a first electric potential, to a charge distribution bus; switching a terminal of a second ultrasonic transducer of the array, at a second electric potential different than the first potential, to the charge distribution bus; and allowing charge to flow between the first ultrasonic transducer and the second ultrasonic transducer through the charge distribution bus.

Abstract: Land seismic survey including providing at least two vibrators in a first group, wherein each vibrator in the first group is assigned to a respective source line, where the source lines of the first group run substantially parallel to one another; providing at least two vibrators in a second group, wherein each vibrator in the second group is assigned to a respective source line that is different than the source lines assigned to vibrators from the first group; actuating the vibrators in the first group simultaneously using different frequency bandwidth sweeps and different phase encodings; actuating the vibrators in the second group at the same time as those in the first group, and simultaneously using different frequency bandwidth sweeps and different phase encodings; and detecting the resulting seismic signals with a plurality of seismic sensors that are placed in contact with the earth and as part of a seismic spread.

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: A method of determining a distance between a vehicle and a sound source includes detecting, at a microphone of the vehicle, sounds from a sound source external to the vehicle. The sounds have a first frequency component at a first frequency and a second frequency component at a second frequency. The method also includes determining, at a processor of the vehicle, a classification of the sound source based on audio properties of the sounds. The method further includes determining a first energy level associated with the first frequency component and a second energy level associated with the second frequency component. The method also includes determining a ratio between the first energy level and the second energy level. The method further includes determining the distance between the vehicle and the sound source based on the ratio and the classification of the sound source.

Abstract: Optical receivers and transmitters can be used as stand-alone systems or combined together as a transceiver. Each of the receiver and transmitter may include an optically reflective steerable device, such as an optically reflective liquid crystal metasurface (LCM), to steer optical radiation to a target location. A transmit waveguide conveys optical radiation from a light source to the transmitter steerable device. A receive waveguide conveys received optical radiation reflected by the receiver optically steerable device to a sensor. In some embodiments, the transmit waveguide and the receive waveguide may be portions of the same planar waveguide. The receiver includes a holographic lens between the receiver LCM and the receive waveguide to pass through optical radiation received at a first range of incident angles and modify (e.g., collimate and/or spectrally filter) optical radiation reflected by the receiver LCM for conveyance by the receive waveguide to the sensor.

Abstract: The disclosed systems, structures, and methods are directed to a LiDAR system comprising a radiation source configured to emit light pulses towards a region of interest (ROI), a detector configured to detect light pulses reflected from the ROI, a processor, communicatively coupled to the radiation source and the detector, configured to cause the radiation source to emit a preamble light pulse having an energy EP and a pulse width W1 towards the ROI, determine, if the preamble light pulse is detected by the detector and whether there is an object in the ROI, responsive to a determination that there is an object in the ROI, cause the radiation source to emit a scanning light pulse having an energy EL and a pulse width W2 towards the ROI, else the radiation source to emit a scanning light pulse having an energy EH and the pulse width W2 towards the ROI.

Abstract: Embodiments include a primary short circuit (PSC) coupled to a primary side of a transformer and a dampening element, coupled to a transducer coupled to a secondary side of the transformer, configured to dampen a received signal during a portion of a reverberation period. The PSC and the dampening element may be activated substantially simultaneously. Activation of the PSC circuit mitigates a parallel resonance otherwise arising, in part, in the transducer, but, increases the received signal by a DC shift voltage. The dampening element dampens the DC shift voltage. The received signal may be dampened prior to amplification of the received signal by an amplifier. The dampening facilitates earlier and more precise measurement, during the reverberation period, of at least one operating characteristic for the PAS sensor. Another embodiment prevents the DC shift voltage by selectively activating the PSC within a determined time of a zero-crossing of a given signal.

Abstract: A light detection and ranging system includes synchronously scanning transmit and receive mirrors that scan a pulsed fanned laser beam in two dimensions. Imaging optics image a receive aperture onto an arrayed receiver that includes a plurality of light sensitive devices. Scanning mirror offsets may be applied to modify a fan angle of the pulsed fanned laser beam. Adaptive methods dynamically modify the size and location of the field of view, laser pulse properties, and/or fan angle in response to internal and external sensors data.

Abstract: A method for underwater acoustic communication includes steps of S1: capturing a synchronization signal using a cross-correlation operation; S2: performing time forward shifting and reversing processing and time backward shifting and reversing processing, respectively, on the synchronization signal to obtain a forward shifted time reversal coefficient and a backward shifted time reversal coefficient; S3: performing a convolution operation of the forward shifted time reversal coefficient and the backward shifted time reversal coefficient, respectively, with a subsequently captured information sequence to obtain a forward shifted time reversal output and a backward shifted time reversal output; S4: processing the forward shifted time reversal output and the backward shifted time reversal output, respectively, with a forward shift equalizer and a backward shift equalizer to obtain two sets of equalizer outputs; and S5: selecting one of the two sets of equalizer outputs with a smaller error for data decoding to o

Abstract: An ultrasound diagnostic apparatus of the present invention includes: a transmitter that generates and outputs a plurality of drive signals to a transducer of an ultrasound probe, the drive signals causing the transducer to transmit a plurality of transmission ultrasound waves that have different waveforms in a temporally shifted manner, the drive signals being compensated for asymmetry of the transmission sound pressure waveforms of the plurality of transmission ultrasound waves transmitted from the transducer; and a hardware processor configured to extract a harmonic component according to a plurality of reception signals, and generating an ultrasound image based on the extracted harmonic component.

Abstract: Embodiments of the disclosure provide an optical sensing system, a range estimation system for the optical sensing system, and a method for the optical sensing system. The exemplary optical sensing system includes a transmitter configured to emit a plurality of laser pulses towards an object. The optical sensing system further includes a range estimation system configured to estimate a range between the object and the optical sensing system. The range estimation system includes an analog to digital converter (ADC) configured to convert a plurality of laser pulses returned from an object to a digital signal. The ADC has a predetermined sampling period. The exemplary system further includes a processor. The processor is configured to calculate an intensity ratio between two data points selected from the digital signal.

Abstract: An acoustic imaging metamaterial is provided for obtaining edge detection information of a tangible object. The acoustic imaging metamaterial includes a longitudinally extending phononic crystal substrate that defines a first major surface and a second major surface opposite the first major surface. A first structurally rigid grating layer is disposed adjacent the first major surface, and a second structurally rigid grating layer is disposed adjacent the second major surface. In various aspects, the first and second structurally rigid grating layers are identical in shape and dimensions, and are aligned with one another. The acoustic imaging metamaterial is configured to redirect, confine, and/or manipulate an incident acoustic wave resulting in a high contrast image used for extracting edge detection information of the tangible object. The background medium fluid of the system can be air or a fluid such as water.

Abstract: In an ultrasonic detection system that uses frequency-modulation or phase-modulation coding to distinguish emitted bursts from multiple transducers, a receiver associated with a transducer uses peak search, peak buffer, and peak rank stages in one or more receiver signal processing paths to identify valid received ultrasonic signal envelope peaks in correlator outputs. The peak rank stage can support different modes respectively designed to handle one code, two or more codes, or two or more codes with support for Doppler frequency shift detection. Valid peak information (e.g., amplitude and time) can be reported to a central controller and/or stored locally in a fusion stage to generate more intelligent information for targets or obstacles using peaks from multiple bursts.

Abstract: An object detection device includes: a wave receiver that receives a reflected wave generated by reflection, by an object, of a transmission wave incident on the object; a determination section that determines whether, in a change over time in an amplitude of the reflected wave received by the wave receiver, an amplitude of a falling portion is greater than a predetermined criterion, the amplitude of the falling portion being decreased after the amplitude has reached a maximum value; and a processing section that, on the basis of a determination by the determination section that the amplitude of the falling portion is greater than the predetermined criterion, performs a process in which the object is treated as an object to be avoided.

Abstract: A method for positioning an underwater glider based on a virtual TDOA of a single beacon is provided. In the method, a positioning beacon periodically sends positioning messages, where the positioning message includes longitude, latitude and depth information of the positioning beacon; the underwater glider receives the positioning messages and records TOAs at which the positioning messages arrive at an acoustic positioning signal receiving module; and the underwater glider parses the positioning messages and stores positioning message data, creates virtual beacons based on beacon information and attitude information of the underwater glider, corrects the TOAs, and calculates a position of the underwater glider according to a TDOA algorithm. According to the method, the underwater glider passively listens to and receives the positioning messages without sending a positioning request to the positioning beacon, making the entire positioning process energy-saving with a certain degree of concealment.

Abstract: Systems and methods provide for the reduction of motion at a ground layer of a site due to a seismic event. A predicted seismic motion is obtained for a geological layer at depth and properties of the layers between the ground layer and layer at depth are determined. A model is created using the layers and the predicted seismic motion. Iteratively for each layer, one or more properties of the layer is changed in the model and a site amplification is performed to determine a change or changes that result in an acceptable response at the ground layer. Subsequently, the in situ layer may be modified according to the modified property or properties to reduce motion at the site due to a seismic event.