Abstract: Methods and systems for acoustic sensing include determining sensing locations along a fiber to generate a beam pattern that is directed to an acoustic source. An optical pulse is transmitted on the fiber. Optical phase of backscattering light is measured from the sensing locations on the fiber. An output signal is generated by combining the measured optical phase according to the beam pattern.

Abstract: Disclosed are systems and methods directed to a frequency analysis approach to transformer status monitoring using distributed fiber optic sensing to monitor a phase delay of a 120 Hz vibrational signal and determining an angular difference between a designated point and a reference point. Operationally, systems and methods according to aspects of the present disclosure identify phase delay patterns of a single transformer from its vibrational humming and combined vibrational signals of multiple transformers.

Abstract: A signal acquisition unit acquires a plurality of signal groups acquired based on backscattered light from a plurality of long gauge length sections and a plurality of signal groups acquired based on backscattered light from a plurality of short gauge length sections, which are set in an optical fiber used for distributed acoustic sensing. A signal selection unit selects a long gauge length section based on a first signal feature of each of signal groups of the plurality of long gauge length sections, and selects a plurality of short gauge length sections corresponding to the selected long gauge length section. A section estimation unit determines one short gauge length section, as a section in which an event has occurred, based on a second signal feature of each of signal groups of the plurality of selected short gauge length sections.

Abstract: Disclosed are systems and methods directed to a MIMO method that detects and localizes an object without requiring the object to emit a sound. Operationally, multiple speakers generate tone signals at different frequencies, while multiple acoustic sensors demodulate the complex amplitude of each frequency. By monitoring the feature variation of the relative phase (or intensity) vector from the complex amplitude, our method detects or localizes movement of the object. For large-scale applications, a fiber-optic system and method that employs distributed acoustic sensing (DAS) in which an optical fiber is used as one or more acoustic sensors located at points along the length of the optical fiber. A single DAS system provides numerous sensors using only a single optical fiber thereby enabling perfect synchronization and centralized signal processing. Notably, with such a DAS arrangement, cost and complexity is significantly reduced, while privacy is preserved.

Abstract: An improved near-infrared spectroscopy based handheld tissue oxygenation scanner and method in which the handheld tissue oxygenation scanner is a small device-like an optical mouse-employing a single transmitter-receiver pair, an optical switch, and a plurality of optical fibers that transmit light into tissue under examination and receive light after interacting with that tissue. The integration of a plurality of optical fibers wherein each individual one provides emission/reception of infrared radiation advantageously provides a higher density of tissue interrogation by the infrared radiation thereby providing faster operation and more information in a given time period. Additional features and advantages of our inventive system and method include computer control and the ability to connect to a variety of computing devices via BlueTooth and other communications techniques.

Abstract: It is an object of the present disclosure to provide a signal processing apparatus, a system, a method, and a non-transitory computer-readable medium capable of estimating the signal generation position in consideration of the optical fiber laying information and the optical fiber gauge length. A signal processing apparatus according to the present disclosure includes: a signal source candidate generation means configured to generate a plurality of signal source candidate positions; a composite data generation means configured to calculate a distortion signal, which is generated when a signal generated from a signal source distorts an optical fiber, based on a plurality of pieces of optical fiber laying information, a plurality of optical fiber gauge lengths, and the plurality of signal source candidate positions.

Abstract: Provided is a signal processing apparatus including: an acquisition unit configured to acquire a phase difference signal of backscattered light of laser light, by an optical fiber sensor configured to convert dynamic distortion of an optical fiber, at a first gauge length that is a predetermined section, into a phase difference of the backscattered light of the laser light passing through the first gauge length; and a control unit configured to perform signal processing to obtain phase difference data of the backscattered light of the laser light at a second gauge length shorter than the first gauge length, from the acquired phase difference signal of the backscattered light of the laser light.

Abstract: An information processing device includes an acquisition unit that acquires measurement signals measured at a plurality of measurement points on a laid optical fiber cable, a prediction unit that predicts a predictive environment representing the environment of each of the measurement points from each of the measurement signals by using a prediction model set in advance, and a correction unit that corrects the predictive environment on the basis of a comparison between the predictive environment of each of the measurement points and the measurement signal measured at each of the measurement points.

Abstract: This optical fiber real-space distribution calculation system includes propagation signal output means outputting a propagation signal propagating in a non-contact manner via a vibration medium to an optical fiber; reception time difference calculation means calculating a reception time difference of the propagation signal between adjacent measurement points; coordinate information acquisition means acquiring coordinates of a measurement point on the optical fiber and coordinates of the propagation signal output means; and measurement point calculation means calculating coordinates of each measurement point on the optical fiber by repeating calculation of an intersection between a circle centered on coordinates of the measurement point with a distance of the predetermined length segment as a radius and a circle centered on coordinates of the propagation signal output means as a next measurement point adjacent to the current measurement point, based on the calculated reception time difference of the propagatio

Abstract: Disclosed are systems, methods, and structures employing a distributed fiber optic sensing (DFOS)/distributed acoustic sensing (DAS) system operating as an underwater wireless acoustic antenna in which an optical fiber sensor cable serves as a distributed acoustic antenna that receives multiple data from transmitters using an optical interrogator. Sensing channels, in the form of acoustic-antenna-array systems are located near transmitters taking advantage of the fact that these channels are automatically synchronized. The sensing channels may also be manually selected from software controlling the interrogator, and acoustic repeaters may be introduced as one data transmission mechanism. Acoustic tata transmission using an orthogonal frequency division multiplexed (OFDM) signal is demonstrated as a cure for data transmission using a DAS, such as multipath fading impacting bit error rate (BER) and limitations in acoustic transmission bandwidth.

Abstract: An object of the present disclosure is to provide a signal source position estimation apparatus, a system, a method, and a non-transitory computer-readable medium that are capable of accurately estimating positions of a plurality of different signal sources even when signals are generated from the plurality of signal sources at substantially the same time. The signal source position estimation apparatus according to the present disclosure includes: a time difference of arrival (TDOA) candidate value evaluation means for calculating, for all combinations of two sensors selected from among a plurality of sensors, all candidate values of a time difference of arrival being a difference in time of arrival (TOA) of signals generated from each of a plurality of signal sources between the two sensors; and a solution candidate distribution derivation means for deriving a solution candidate distribution formed by distributing whether predetermined coordinates are coordinates of the plurality of signal sources.

Abstract: The optical fiber sensor includes a setting unit which sets a section to be evaluated set in the optical fiber to one of a first section and a plurality of second sections, each of which is shorter than the first section, an extraction unit which extracts a state change of light from the optical fiber, and a detection unit which detects a change in the surrounding environment based on time-series data of the state change of light in the section to be evaluated.

Abstract: An improved near-infrared spectroscopy (NIRS) based handheld tissue oxygenation scanner employing a single transmitter-receiver pair, an integral inertial measurement sensor, an optional optical tracker, and wireless communications. Operational coordination among/between the elements are performed by a processor. The NIRS scanner device has a small foot print and permits the use of only a single transmitter/receiver pair to scan a large area of tissue manually, in real-time. Additional features and advantages of include battery power, hand held, may connect to a variety of computing devices via BlueTooth and/or WiFi, and may be modified to employ multiple transmitter/receivers to improve sensitivity and obtain absolute measurements.

Abstract: An optical fiber sensing system according to the present disclosure includes an optical fiber, an interrogator connected to the optical fiber, and a vibration device disposed in a vicinity of the optical fiber. The vibration device acquires weather information regarding an installation location of the vibration device, and applies vibration according to the acquired weather information to the optical fiber. The interrogator detects vibration applied to the optical fiber by the vibration device, based on an optical signal received from the optical fiber, and determines weather conditions at the installation location of the vibration device, based on the detected vibration.

Abstract: An evaluation apparatus according to the present disclosure includes at least one memory storing a set of instructions, and at least one processor configured to execute the set of instructions and thereby to acquire, from a sensor, time-space data on vibrations that have occurred in an overhead optical fiber strung between poles, and evaluate, for each of predetermined analysis sections, a wind velocity and a propagation speed of wind in the analysis section based on the time-space data, and evaluate a wind direction in the analysis section based on the evaluated wind velocity and the propagation speed of the wind.

Abstract: A signal processing apparatus according to the present disclosure includes: at least one memory configured to store instructions; and at least one processor configured to execute the instructions to: acquire signals measured by a signal measurement apparatus at a plurality of points located along an optical fiber; and determine whether there is an event based on a degree of similarity between the signals measured at points adjacent points.

Abstract: An apparatus includes memory and processor configured to: input, from a sensor, a signal indicating a characteristic vibration occurring at each position of an optical fiber, and estimate, based on the input signal, an aerial section in which the optical fiber being aerially laid over a pole is present; calculate, based on the input signal, sensing data indicating a vibration characteristic of each position of the optical fiber being present in the aerial section, and calculate a difference degree of the sensing data between two neighboring points of the optical fiber; and temporally integrate the difference degree, calculate a time average of the difference degree, estimate, based on a time average value of the difference degree, a position of the pole and a position of an extra length section of the optical fiber, and output an estimation result of positions of the pole and the extra length section.