98 results about "Phase sensitive" patented technology

The invention discloses a self-adaptive filtering and intelligent separation method for a multi-mode partial discharge signal, and relates to the technical field of insulation state monitoring and signal processing of power equipment, and the method comprises the following steps: S1, collecting the partial discharge signal of the power equipment in real time, and synchronously obtaining an equipment operation parameter and an environment noise signal; according to the adaptive filtering and intelligent separation method for the multi-modal partial discharge signal, the problems of modal aliasing and feature distortion caused by signal and noise time-frequency coupling in a dynamic noise environment in a traditional method are effectively solved through a cooperative mechanism of dynamic coupling degree modeling and dual-channel adversarial decoupling. The dynamic coupling path sensing module quantifies interaction characteristics of noise and signals in real time, and realizes accurate suppression of high-frequency transient interference and low-frequency periodic noise in combination with a double-channel architecture of complex field phase sensitive filtering and vibration trajectory matched filtering.

The invention relates to the technical field of photoetching machine calibration, and discloses a photoetching machine calibration method, device and equipment based on multi-view vision, and the method comprises the following steps: carrying out imaging and phase sensitive detection analysis on a mask plane and a wafer plane through a four-path optical beam splitting system to obtain four groups of mask-wafer initial alignment position information; performing scanning white light interference edge enhancement processing to obtain three-dimensional surface contour data; performing wavelet transform processing on the three-dimensional surface contour data, and performing dynamic registration on the four-path optical beam splitting system to obtain multi-view visual feature registration data; a comprehensive error model including mechanical errors, optical errors and environmental errors is established, real-time correction and error compensation are carried out on a six-degree-of-freedom motion platform of the photoetching machine, a multi-view vision calibration result of the photoetching machine is obtained, the influence of environmental vibration and thermal drift on calibration precision is effectively eliminated, and the calibration accuracy of the photoetching machine is improved. The optical system is ensured to be always in the optimal imaging state, and the calibration precision is improved.

The invention relates to a phase-sensitive optical time domain reflectometer based on multi-frequency reference switching. Continuous laser generated by a continuous laser is divided into a local path and a detection path through an optical coupler; the local path is input to the polarization coherent receiving module, the detection path is incident to a light intensity modulator driven by the signal generation circuit module, and the light intensity modulator is converted into a multi-frequency pulse laser sequence with intensity modulation; the multi-frequency pulse laser sequence enters the sensing optical fiber to be measured through the optical circulator; generated Rayleigh backscattered light and local continuous laser are subjected to beat frequency coherent receiving in a polarization coherent receiving module through a circulator; and the signal acquisition circuit adopts a demodulation algorithm to compensate phase drift and sensitivity difference of detection pulse demodulation signals with different frequencies so as to realize dynamic strain sensing. Compared with the prior art, the phase drift and the sensitivity difference between the frequencies are extracted to realize the compensation of the interleaved signals, and the method does not depend on the fixed reference frequency, so that the robustness and the adaptability of the system in a complex environment are remarkably enhanced.

The invention relates to a phase-sensitive optical time domain reflectometer based on a parallel frequency division multiplexing sequence. Continuous laser is divided into a local path and a detection path through an optical coupler; the local path is input to the polarization coherent receiving module, the detection path is converted into a pulse laser sequence with intensity modulation through a light intensity modulator driven by a radio frequency signal provided by the signal generation circuit module, and the radio frequency signal is composed of two frequency division multiplexing sequences with difference; the pulse laser sequence enters the sensing link to be measured to generate Rayleigh backscattered light, and the Rayleigh backscattered light and local continuous laser are subjected to beat frequency coherent receiving through a circulator; and the signal acquisition circuit is used for sampling and analyzing the interference signal, and performing frequency domain comparison on an interleaving result of the two frequency division multiplexing pulse sequences to eliminate a harmonic frequency and retain a real strain signal frequency. Compared with the prior art, the non-harmonic strain signal measurement is realized, the high-frequency response performance and the high-precision strain measurement capability are excellent, and meanwhile, the long-distance coverage capability is also realized.

The invention discloses a double-core optical fiber integrated MZ interferometer based on thermal diffusion. The interferometer is mainly characterized in that a core structure of the interferometer is formed by sequentially welding an input optical fiber (1), a first double-cladding transition optical fiber (2), a double-core optical fiber (3), a second double-cladding transition optical fiber (4) and an output optical fiber (5). Thermal diffusion treatment is performed by long-term high-temperature heating in the welding regions (A) and (B). The thermal diffusion treatment enables fiber core doping elements to be diffused, a transition area is formed in the double-clad optical fiber, the coupling efficiency between the single-mode optical fiber and the double-core optical fiber is remarkably improved, and compared with a traditional tapering structure, the thermal diffusion area is higher in mechanical strength. The interferometer device is compact in structure, high in integration level and excellent in interference contrast, can realize high-precision phase sensitive sensing, is suitable for distributed measurement of physical quantities such as temperature, bending and refractive index, and can be widely applied to optical fiber sensing.

The invention discloses a phi-OTDR (Optical Time Domain Reflectometer) vibration signal classification method based on multi-scale residual convolution and a bidirectional long-short-term memory network, relates to the technical field of phase-sensitive optical time domain reflectometer vibration sensing, and solves the problems of insufficient feature extraction, single model fusion mechanism, poor system real-time performance and the like of an existing phi-OTDR vibration signal classification method. The method is realized through the steps of a multi-scale deep convolutional network, a bidirectional long-short term memory network, a cross attention fusion module, a learnable gating mechanism and the like. A cross attention fusion module is adopted, association between spatial features and time sequence features is dynamically established in a double-path network, feature interaction and information coupling are deepened, and the sensing ability of the model to key information is remarkably improved. Meanwhile, the fusion proportion of the multi-path features is adaptively adjusted according to the actual distribution of the input features, background noise interference is effectively suppressed, and the robustness and discrimination performance of the model are enhanced. Accurate identification and classification of external vibration signals are realized.

The invention provides a phase-sensitive optical time domain reflectometer system and method, and the system comprises a first polarization-maintaining coupler which is used for dividing laser generated by a DC laser, and obtaining first laser and second laser; the optical fiber measurement front-end module is used for processing the random signal through pulse shaping and multi-carrier modulation technologies to generate an electric signal, and sequentially performing modulation, amplification, Rayleigh scattering and amplification on the first laser after the electric signal is generated to obtain amplified Rayleigh backscattered light; the second polarization-maintaining coupler is used for dividing the second laser to obtain third laser and local oscillation light; the delay optical fiber is used for processing the third laser to obtain delay light; the third polarization-maintaining coupler is used for combining the delayed light and the amplified Rayleigh backscattered light to obtain combined light; the receiver is used for processing the combined light and the local oscillation light to obtain multiple paths of target electric signals; and the oscilloscope is used for processing multiple paths of target electric signals through low-pass and high-pass filters and a phase noise compensation algorithm so as to determine power and phase distribution. The system cost can be reduced.

The invention discloses a bearing fault acoustic detection method and system based on fractional harmonic phase-locked amplification, and the method comprises the steps: obtaining an acoustic signal of a target motor, measuring the shaft rotation frequency of a motor shaft in real time, synchronizing the shaft rotation frequency to a fractional phase-locked loop, and carrying out the calculation of a bearing fault characteristic frequency according to the geometric parameters of a bearing, the bearing fault characteristic frequency is a non-integer multiple of the shaft rotation frequency, generating a reference signal synchronous with the bearing fault characteristic frequency through a fractional phase-locked loop, and performing phase sensitive detection on the obtained acoustic signal and the generated reference signal by using a phase-locked amplifier, specifically, performing orthogonal demodulation on the acoustic signal and the reference signal, and performing phase sensitive detection on the obtained acoustic signal and the reference signal. The method comprises the following steps: generating an in-phase component and an orthogonal component, extracting a direct-current component through low-pass filtering, calculating to obtain a vibration amplitude and phase information corresponding to a bearing fault characteristic frequency, and judging the type and severity of a bearing fault according to the comparison between the vibration amplitude and a preset baseline, the harmonic consistency and the phase stability.

The invention discloses a composite hose structure for fuel gas transmission, and relates to the technical field of fuel gas transmission and distribution equipment, the composite hose structure comprises a dual-mode quick sealing assembly, dual-mode monitoring is formed by an FBG sensor, a phase-sensitive optical time domain reflectometer and a carbon tube composite filament, the FBG sensor can capture fine strain of a reinforced fiber layer in real time, and the phase-sensitive optical time domain reflectometer can capture the fine strain of the reinforced fiber layer in real time; the phase-sensitive optical time domain reflectometer detects and captures stress waves generated by crack propagation in a material through broadband sound waves, early recognition of millimeter-level damage in a pipe is achieved, grids woven by carbon tube composite filaments are utilized, continuity of the grids is monitored in real time through alternating-current impedance measurement, and the detection accuracy of the millimeter-level damage in the pipe is improved. When local grid resistance is increased due to breakage of the reinforced fiber layer, a micro-damage area can be accurately positioned, when leakage occurs, the memory alloy spring receives an electric signal monitored by a dual-mode, then axial thrust is generated to push the outer side of the fluororubber sealing ring, the fluororubber sealing ring expands in the radial direction under the thrust action of the memory alloy spring, and the leakage is prevented. And rapid and effective mechanical hard sealing is realized.

The invention discloses a distributed sound wave sensing device based on PDH frequency locking and a demodulation method. The distributed sound wave sensing device comprises a narrow linewidth laser, a first optical fiber coupler, a heterodyne phase sensitive optical time domain reflectometer and a frequency stabilization feedback module. The frequency stabilization feedback module comprises a frequency stabilization modulation and demodulation module, a reference cavity and a server; the frequency stabilization modulation and demodulation module comprises an electro-optical modulator or an acousto-optical modulator, a photoelectric detector, a multiplier and a low-pass filter; the first path of light enters a reference cavity for resonance after being modulated by an electro-optical modulator or an acousto-optical modulator, a resonance signal enters a photoelectric detector through cavity reflection, and a signal output by the photoelectric detector is subjected to signal demodulation by a multiplier and a low-pass filter and then is used as feedback to be input into a server for proportional-integral processing; the laser is fed back and output to a modulation interface of the narrow-linewidth laser, and frequency compensation is performed on the laser, so that the laser is locked on the reference cavity; according to the invention, through frequency stabilization and homologous modulation and demodulation, line width and phase drift of the laser can be suppressed at the same time.

The application provides a phase-sensitive optical time domain reflectometer, a measurement method and a readable storage medium, wherein a signal generation circuit of the phase-sensitive optical time domain reflectometer is configured to generate a radio frequency signal to drive an optical intensity modulator to modulate probe light, so that two groups of frequency division multiplexing sequences with differences can be used to synchronously detect a sensing optical fiber to be measured, a differential unfolding algorithm is combined to accurately solve a phase change amount in adjacent sampling intervals, and then demodulation results corresponding to different frequency parts are respectively unfolded to obtain unfolded phase results, so that the problem of large strain phase folding is solved and a large strain range is recovered, and further, the unfolded phase results are rearranged and combined in time sequence through time sequence interleaving processing of the unfolded phase results, so that a high sampling rate and a distortion-free reconstruction result are reconstructed, and therefore, the application can realize accurate measurement of high frequency response and large strain range dynamic strain.

The application discloses a phase-sensitive pre-amplification method based on an electro-absorption modulated laser, and is applied to a star-ground laser communication system receiving end. A distributed feedback laser in the electro-absorption modulated laser amplifies weak pump light after long distance transmission, and generates idler light under the nonlinear effect of a laser cavity; an electro-absorption modulator in the electro-absorption modulated laser detects phase error information between signal light, pump light and idler light, and constructs an optical injection phase-locked loop through a feedback loop, so that stable control of the three-wave phase relationship is realized. Under the phase stability condition, the output light of the electro-absorption modulated laser is fed into a later-stage nonlinear medium to complete phase-sensitive pre-amplification. The phase-sensitive pre-amplification method based on the electro-absorption modulated laser has the advantages of simple structure and easy integration, can realize pump light amplification, idler light generation and phase error suppression under the condition of weak pump light, and effectively improves the receiving sensitivity performance of the star-ground laser communication system.

The invention discloses a carrier roller fault diagnosis method and system based on coupled vibration analysis, and the method specifically comprises the steps: separating a phase-sensitive optical time domain reflection signal based on a physical parameter of a conveying system, separating the phase-sensitive optical time domain reflection signal into a direct vibration signal and a conveying belt conduction vibration signal, recording the direct vibration signal as a first frequency band signal, and recording the second frequency band signal as a second frequency band signal; recording the conveying belt conduction vibration signal as a second frequency band signal; calculating a feature vector of the first frequency band signal to obtain a first feature vector set; calculating a feature vector of the second frequency band signal to obtain a second feature vector set; and carrying out feature fusion on the first feature vector set and the second feature vector set, and obtaining probability distribution of fault categories based on fused features. According to the method, the physical phenomenon of'conveying belt-carrier roller coupling vibration 'is systematically utilized for the first time, the defects that an existing method is single in dimension and prone to being interfered are overcome through double-channel feature fusion analysis, and the accuracy and robustness of early fault diagnosis of the carrier roller of the long-distance belt conveyor are remarkably improved.

The invention relates to the technical field of capacitance detection circuits, in particular to a capacitance digital conversion circuit based on phase-sensitive integration. The circuit comprises a phase shift circuit unit, a capacitance detection unit, a phase control unit and a digital processing unit. According to the invention, an excitation signal is converted into an excitation signal which is 90 degrees ahead by using a phase shift circuit through a phase shift circuit unit, a capacitance detection unit controls a single-pole double-throw switch S1 to alternately access the excitation signal and an inversion signal to a to-be-detected capacitor Cx and a reference capacitor C0, and a phase control unit utilizes integration-deintegration double stages in an integration stage. Phase signals are converted into high and low levels through a comparator so as to control overturning of a capacitor CF pole plate, the digital processing unit carries out phase sampling counting at 0 degree and 180 degrees, the capacitance value is calculated according to the ratio of the number of integration cycles to the number of deintegration half cycles, the influence of stray capacitance is reduced, and the measurement precision is improved.

The present invention provides a vision-based path planning method for a photovoltaic panel intelligent installation robot, which relates to the field of image data processing. The method comprises: using a phase-sensitive camera to collect real-time data on the photovoltaic panel storage and installation area to generate a holographic data stream; constructing a continuous phase field using a bidirectional space-time grid discretization algorithm based on a wave equation solver, combining it with time-reverse light field prediction to generate pre-compensation parameters, fusing them to form a holographic phase field model and constructing a digital elevation model; using a phase gradient tracking algorithm to avoid terrain undulations and obstacles in global optimal path planning, dynamically optimizing path curvature and movement speed; using time-reverse light field prediction to detect phase break risks in real time and generate microsecond-level correction instructions to adjust the robot's trajectory; and verifying phase deviations through differential analysis after installation, triggering time-reverse light field prediction and reinforcement learning to iteratively optimize model parameters, achieving high-precision adaptive path planning and obstacle avoidance control.

An electromagnetic induction (EMI) system for characterizing geophysical (e.g. subterranean) environments, includes: (a) a transmitter module including a transmission coil and signal transmission electronics; and (b) at least one receiver module including a receiver coil and signal reception electronics wherein the at least one receiver module is physically separated from the transmitter module without a wired signal connection between them, wherein phase information of signals sent by the transmitter module and those received by at least one receiver module are preserved such that phase information of received signals may be determined and used in characterizing the geophysical environment. In some systems, signal preservation uses a pair of correlated, stable, high frequency clocks.

The invention relates to the technical field of light atmosphere, and discloses a light atmosphere effect generation method, which comprises the following steps: generating an initial wave function according to an intensity field, deducing on the basis of a potential energy field to obtain a first wave function, performing intensity calculation and phase extraction from the first wave function to obtain a second wave function, updating the direction field based on the second wave function to obtain an updated direction field and an enhanced optical flow field; three core advantages of light atmosphere generation are realized, firstly, deep coupling of quantum optics and neurocognition is realized, real response of human eyes is simulated through a phase-sensitive light response model, and light atmosphere distribution is enabled to conform to quantum propagation rules and human visual cognition characteristics in combination with a cognition attention focusing mechanism of a DQN model; and 2, a dynamic self-adaptive mechanism runs through the whole process, and a light current coefficient and object motion data are adjusted in real time through the pupil diameter to feed back a new light flow field so as to ensure that the environment change can be quickly responded.

The invention provides a spectral confocal assisted phase-sensitive optical coherence tomography sensing system and method, and the method comprises the steps: connecting a first optical fiber coupler with a broadband light source, and outputting a first light beam and a second light beam at two output ends of the first optical fiber coupler respectively; the confocal probe is located on one side of the to-be-detected sample, receives the first light beam and irradiates the front side and the rear side of the to-be-detected sample through the first light beam to obtain a confocal signal; the interference signal assembly receives the second light beam and measures the to-be-measured sample to obtain an interference signal; the monitoring assembly is connected with the first optical fiber coupler and the interference signal assembly, receives the confocal signal and the interference signal, and obtains the initial thickness and the refractive index of the to-be-detected sample and the change data of the shrinkage strain and the refractive index in the deformation process; according to the invention, the chromatography interference signal and the spectrum confocal signal can be respectively output in one-time spectrum signal acquisition, so that the thickness and the refractive index initial value of the to-be-tested sample can be separated.

This optical transmission system comprises: a phase conjugate conversion device (200) that performs optical parametric amplification in a first optical parametric amplification unit (238) and in a second optical parametric amplification unit (244), monitors electric power of a first polarized component and a second polarized component of first pilot light, controls the phase of higher harmonic wave excitation light by means of phase shifters (218, 224) so as to maximize the optical power of first pilot light to thereby synchronize the phase of the higher harmonic wave and the first pilot light, and controls a phase shifter (264) disposed in at least one path so as to maximize interference waveforms of respective components of second pilot light, which is different from the first pilot light in terms of the wavelength or the optical power and which has passed through from a pilot light source (270) in a reverse direction, to thereby match the optical length of the path of the first optical parametric amplification unit (238) and the path of the second optical parametric amplification unit (244); and a phase sensitive amplification device (400) for performing phase sensitive amplification on idler light and on an optical signal included in an optical transmission signal through optical parametric amplification using the excitation light controlled by using the first pilot light included in the optical transmission signal.

In the present invention, a second harmonic generator (103) generates pump light and local oscillator light from input light that is input to a second input section (102). A first demultiplexer (104) demultiplexes the pump light and the local oscillator light generated by the second harmonic generator (103). A combiner (105) combines the pump light demultiplexed by the first demultiplexer (104) with measurement light, and an amplifier (106) inputs the pump light and the measurement light combined by the combiner (105) and amplifies the measurement light through optical phase-sensitive amplification. An interferometer (108) causes 50 / 50 interference between the local oscillator light demultiplexed by the first demultiplexer (104) and the measurement light demultiplexed by a second demultiplexer (107).

The application discloses a kind of multi-modal partial discharge signal's adaptive filtering and intelligent separation method, and the application is related to power equipment insulation state monitoring and signal processing technical field, comprising the following steps: step S1: real-time acquisition power equipment partial discharge signal, and synchronously obtain equipment operating parameter and environmental noise signal.The multi-modal partial discharge signal's adaptive filtering and intelligent separation method, by dynamic coupling degree modeling and the synergistic mechanism of double-channel confrontation type decoupling, effectively solves the mode aliasing and feature distortion problem caused by signal and noise time-frequency coupling in dynamic noise environment in traditional method.Dynamic coupling path perception module quantifies the interactive characteristics of noise and signal in real time, combined with the double-channel architecture of complex domain phase-sensitive filtering and vibration trajectory matching filtering, realizes the accurate suppression of high-frequency transient interference and low-frequency periodic noise.

A kind of distributed multi-parameter sensing system based on multi-core optical fiber, including laser, laser light source is sent to the signal generator input trigger pulse drive respectively with the signal input end of phase-sensitive optical time domain reflectometer based on Rayleigh scattering and its demodulation device, Raman optical time domain reflectometer based on Raman scattering and its demodulation device, Brillouin optical time domain reflectometer based on Brillouin scattering and its demodulation device are connected, the signal output end of phase-sensitive optical time domain reflectometer and its demodulation device, Raman optical time domain reflectometer and its demodulation device, Brillouin optical time domain reflectometer and its demodulation device is connected with the signal input end of multi-core optical fiber through multi-core optical fiber fan-in fan-out module;The present application utilizes the principle of space division multiplexing, each fiber core in optical cable as separate sensing channel carries out measurement and signal transmission;Multi-core optical fiber fuses three kinds of distributed optical fiber sensing systems together, realizes in-situ measurement and mutual compensation decoupling of temperature, strain and vibration, improves the measurement precision of sensing system.

The application discloses a phase-sensitive optical receiving system for enhancing inter-satellite laser pointing measurement, comprising: an optical transceiver unit for receiving an input laser signal to be measured, collimating and beam-reducing the laser signal to be measured, obtaining a beam-reduced laser signal and outputting the same; a phase-sensitive amplification unit for receiving the input beam-reduced laser signal and pump laser, processing the beam-reduced laser signal and the pump laser, obtaining a power amplified signal and outputting the same; an optical receiver unit for receiving an optical amplified signal and a local oscillation laser, processing the optical amplified signal and the local oscillation laser, obtaining four electronic signals and outputting the same; and a data processing unit for receiving the four electronic signals, demodulating the four electronic signals, obtaining laser pointing information and outputting the same. The application implements noiseless amplification on an incident laser pointing signal through the phase-sensitive optical receiving system, and improves the detection sensitivity of a spacecraft laser pointing system.

The invention relates to a vehicle-type-based traffic flow monitoring DAS system and a signal processing method, and belongs to the technical field of intelligent traffic monitoring. A DAS system for monitoring traffic flow based on different vehicle types is characterized by comprising a sensing module based on a phase-sensitive optical time domain reflection technology and a self-adaptive signal processing module, according to the system, firstly, road vibration data are collected by using an optical fiber distributed acoustic sensing technology, vehicle vibration characteristics are selectively enhanced and background interference is suppressed in a key frequency band of 10-80 Hz through DAS-PCSE based on enhanced ultra-wavelet transform, and high-stability input characterization is generated; then, the preprocessed data are input into a lightweight DAS Trajectory Net, the network takes an encoder-decoder as a skeleton and introduces an adaptive feature enhancement module, and accurate recognition of a vehicle track is achieved; and finally, through a DAS Veple Classifier Net, a double-current signal processing module and lightweight convolution are utilized to efficiently fuse spatio-temporal information, and vehicle type discrimination is completed. According to the invention, the influence of low signal-to-noise ratio and complex background disturbance can be effectively overcome, and wide-area and all-weather vehicle-type-based traffic flow and vehicle speed monitoring can be realized with low calculation cost.

The invention relates to a magnetic resonance image reconstruction method and device, computer equipment and a storage medium, and the method comprises the steps: applying a phase-sensitive inversion recovery pulse sequence to a to-be-imaged object, collecting a magnetic resonance signal of the to-be-imaged object, and obtaining a to-be-processed image according to the magnetic resonance signal; removing a background first-order phase in the to-be-processed image to obtain a first dephasing image; according to the first dephasing image and a preset recognition model, removing a target background zero-order phase in the first dephasing image to obtain a second dephasing image; and extracting a real part component of the second dephasing image to obtain a target magnetic resonance image. By using the magnetic resonance image reconstruction method provided by the invention, the quality of the obtained target magnetic resonance image can be improved.

The present invention relates to the technical field of pattern recognition for phase-sensitive optical time-domain reflectometry, and discloses a method for optimizing pattern recognition feature selection based on a simulated annealing algorithm. The method comprises the following steps: encoding intrusion signal feature parameters and initializing the parameters; selecting an initial intrusion signal feature combination based on the Fisher Score method; determining a fitness function and initiating a simulated annealing algorithm to search for the optimal result; continuously updating the new solution based on the fitness function value of the new solution and the Metropolis criterion for accepting new solutions; and varying the temperature and repeating the iterations until internal and external loop conditions are met, thereby obtaining the optimal intrusion signal feature combination and the optimal fitness function value. The present invention can achieve the selection of an intrusion signal feature combination with a good overall effect, eliminate redundant intrusion signal features, accelerate convergence, and improve the pattern recognition and classification accuracy of the phase-sensitive optical time-domain reflectometry.

This application relates to the field of optical fiber sensing technology, and particularly to a phase demodulation method and system. Among them, the phase demodulation method includes: obtaining a discrete signal corresponding to a beat frequency signal; determining a first target signal corresponding to the discrete signal based on intermediate frequency filtering technology; determining a second target signal and a third target signal based on the first target signal and an orthogonal frequency shift signal, where the second target signal and the third target signal are obtained after mixing and low-pass filtering the first target signal and the orthogonal frequency shift signal; converting the amplitudes of the second target signal and the third target signal to 1; constructing a first function of the second target signal with respect to time and position, and a second function of the third target signal with respect to time and position based on the second target signal and the third target signal; demodulating the differential phase of a phase-sensitive optical time domain reflectometry fiber sensing system based on the first function and the second function. The demodulation efficiency is improved, the noise and error are reduced, and the system complexity and cost are reduced.

The invention relates to the technical field of optical fiber event detection, and discloses a phi-OTDR event detection method, system and device and a medium, and the method comprises the steps: obtaining the optical fiber signal data of an original phase-sensitive optical time domain reflectometer, and carrying out the first processing; constructing a deep learning model based on the residual network, training the deep learning model by using the training set, evaluating the performance through the verification set, and adjusting hyper-parameters according to an evaluation result to optimize the model; and inputting the data after the first processing into a trained deep learning model based on a residual network to extract high-level features of the optical fiber signals, and performing event identification and classification according to the high-level features. According to the method, the problems that the current OTDR event detection signal is interfered in noise, the model is insufficient in tiny event extraction capability, and the deep learning model is slow in convergence speed and poor in generalization capability are solved, automatic and accurate identification of the optical fiber event is realized, and the efficiency and reliability of optical fiber fault diagnosis are greatly improved.

A distributed acoustic sensing (DAS) system may include an optical fiber, a phase-sensitive OTDR (ϕ-OTDR) coupled to the optical fiber, and a processor cooperating with the ϕ-OTDR. The processor may be configured to train a plurality of machine learning networks with DAS data from the ϕ-OTDR based upon different respective optimizers, select a trained machine learning network from among the plurality thereof based upon a game theoretic model, and generate an acoustic event report from the DAS data using the selected trained machine learning network.

The present invention belongs to the field of distributed optical fiber acoustic wave sensing technology, and is a method for suppressing complex multimodal phase noise of a phase-sensitive optical time domain reflectometer, including: obtaining a noise-containing signal by subjecting two beat frequency electrical signals output by a balanced photodetector to I / Q demodulation and unwrapping processing; performing SVMD decomposition to obtain the decomposed modes, and judging the correlation between the modes and the noise-containing signal through the SWPCC method to retain the components with high correlation at the window positions corresponding to the modes; traversing all modes, and accumulating all the components to be retained according to the corresponding window positions to obtain a phase noise cancellation result. In the process of calculating the correlation between each mode and the original signal in the present invention, the influence of irrelevant components in the mode on the correlation coefficient is eliminated, and the signal-to-noise ratio of the DAS signal is significantly improved.