26 results about "Time domain electromagnetics" patented technology

The invention discloses a radiation source individual identification method, system and device based on space-time information separation, and relates to the field of radiation source individual identification, and the method comprises the steps: obtaining a to-be-detected time domain electromagnetic signal; inputting a to-be-detected time domain electromagnetic signal into the trained radiation source individual identification model to obtain a radiation source individual, and completing the identification of the radiation source individual; the radiation source individual identification model comprises a signal preprocessing and feature enhancement module, a multi-scale spatial feature coding module, a time sequence dynamic modeling module and a space-time cross attention fusion module which are connected in sequence; a loss function for training of the radiation source individual identification model adds triple loss on the basis of standard cross entropy loss. According to the invention, the accuracy and the recognition efficiency of radiation source individual recognition can be improved.

The invention relates to the technical field of geophysical electromagnetic data exploration, in particular to a three-dimensional time-frequency domain electromagnetic joint inversion method based on a finite element algorithm. The method comprises the following steps: respectively acquiring time domain and frequency domain electromagnetic observation data of a to-be-measured region; dividing a to-be-measured region to obtain a non-structural tetrahedral mesh to construct a time-frequency domain inversion initial model; performing forward modeling calculation on the time-frequency domain inversion initial model to obtain time domain and frequency domain electromagnetic response data; obtaining a time domain electromagnetic data residual error and a frequency domain electromagnetic data residual error, respectively obtaining corresponding adaptive weights, and establishing a joint inversion objective function; performing iterative solution on the joint inversion target function, and calculating an update vector of the inversion initial model; and iteratively updating the initial inversion model until a set condition is met, and completing the time-frequency domain electromagnetic joint inversion. According to the method, the accuracy of three-dimensional inversion is effectively improved through joint inversion, so that the practical effect of three-dimensional inversion is enhanced.

The invention discloses a transient electromagnetic data polarizability extraction method based on frequency domain resistivity, and the method comprises the following steps: designing measuring line and wire emission source positions in a test mining area, selecting observation parameters, and collecting field electromagnetic data, the field electromagnetic data comprising transient electromagnetic method electric field data and frequency domain electromagnetic method electric field data; performing inversion on actually measured frequency domain electromagnetic method electric field data by adopting an Occam inversion algorithm to obtain resistivity characteristics of different measuring points, and further obtaining resistivity distribution information; and taking the resistivity distribution information obtained by inversion as a constraint condition of transient electromagnetic method electric field data inversion, performing transient electromagnetic method polarizability inversion by analyzing a relationship between the resistivity and a time constant, and extracting the polarizability. By analyzing and processing the frequency domain electromagnetic data and the time domain electromagnetic data, the resistivity and the polarizability can be accurately extracted, parameter separation is achieved, and the problem of traditional time domain inversion coupling is solved.

The application discloses a semi-airborne full-time electromagnetic forward method based on an Octree grid, which performs spatial discretization on time-domain Maxwell equations, thereby effectively reducing unknowns of equations to be solved. For full-time electromagnetic field numerical simulation, the application combines the high calculation precision of the second-order backward Euler method with the high OFF-Time calculation efficiency of the model reduction algorithm, adopts the second-order BDF and the model reduction algorithm to respectively solve ON-Time and OFF-Time time-domain control equations, forms a joint algorithm to realize simulation of semi-airborne time-domain electromagnetic full-time response, and finally completes the forward calculation process. Through numerical simulation verification, in the full-time transient electromagnetic forward process, the application can keep small occupied memory and also has higher calculation efficiency, and the calculation precision is not lower than that of other methods.

The present invention relates to the field of geophysical exploration technology, and in particular to a physical simulation method, device and system for a time domain electromagnetic method. The system comprises an electromagnetic signal transmitter, a DC stable power supply, a receiver and a transient electromagnetic signal acquisition instrument. The receiver is used to carry the surrounding rock part and the abnormal body part of the manufacturing material of the physical simulation model; the DC stable power supply is used to power the electromagnetic signal transmitter, and the electromagnetic signal transmitter is used to transmit a bipolar rectangular pulse current. The pulse width and off time of the bipolar rectangular pulse current are determined according to the time constant of the abnormal body part; and according to the parameter characteristics of the surrounding rock part, the diffusion distance of the transmitted signal in the surrounding rock part over time is determined, and a data collection time period is selected according to the diffusion distance. Then, the receiver synchronously collects electric field data and magnetic field data within the data collection time period through a receiving electrode and a flux gate arranged on its surface, and forwards the data to the transient electromagnetic signal acquisition instrument for analysis.

The invention relates to the technical field of time-domain electromagnetic geological exploration, in particular to a time-domain superconducting electromagnetic multi-effect multi-parameter extraction method and system, and the method comprises the steps: calculating time-domain superconducting electromagnetic induction-polarization-magnetization multi-effect response, and constructing a data error fitting term based on the multi-effect response and the residual error of measured data; constructing a constraint matrix of multi-parameter correlation coefficients including resistivity, polarizability and magnetic susceptibility, and constructing a multi-parameter statistical constraint term for describing statistical correlation among multiple parameters based on the constraint matrix; constructing a regularization objective function; an improved Gaussian-Newton optimization algorithm is adopted, the regularization objective function is minimized, the optimal value of the regularization objective function is iteratively solved, and the resistivity, the polarizability and the magnetic susceptibility are obtained through synchronous inversion. According to the invention, multi-parameter efficient and accurate extraction imaging in the deep mineral exploration and geological structure identification field is realized.

The invention provides a time domain finite element fast algorithm for electromagnetic force coupling simulation of a loudspeaker, which comprises the following steps of: performing three-dimensional modeling on a micro loudspeaker, setting parameter information of a solving region, and extracting a calculation model; performing discretization processing on the micro loudspeaker model by using a tetrahedral mesh; an electromagnetic force coupling discrete process is deduced, a hybrid finite element fast time domain solver is constructed, a discrete model and solving parameters of the miniature loudspeaker are imported into the solver, and the solver is initialized; and carrying out coil geometric analysis, calculating the current density in the coil, taking the current density as an excitation source of a magnetic field, calling a hybrid finite element fast time domain solver, calculating to obtain the displacement of the vibrating diaphragm, and finally obtaining the time domain vibration curve of the vibrating diaphragm. According to the time domain hybrid finite element fast algorithm, the tree-cotree technology and the Lanczos modal order reduction technology are introduced, the method can be used for analyzing the time domain electromagnetic force coupling simulation problem of the complex micro loudspeaker, and the method has the advantage of being high in solving efficiency under the condition that the solving precision is met.

The application discloses a borehole time domain electromagnetic far detection device and method, which comprises a ground system, an armored cable, a remote transmission system and a time domain electromagnetic logging instrument; the remote transmission system is connected with the time domain electromagnetic logging instrument and is arranged in a borehole; the time domain electromagnetic logging instrument comprises an electronic circuit, an acquisition module and a transmission module which are sequentially arranged from top to bottom; the electronic circuit is connected with the acquisition module and the transmission module for detection; the acquisition module comprises a first array type three-component magnetic receiving sensor, a second array type three-component magnetic receiving sensor, an electric receiving sensor, a third array type three-component magnetic receiving sensor and a fourth array type three-component magnetic receiving sensor which are sequentially arranged from top to bottom; and the transmission module comprises a magnetic source and an electric source which are sequentially arranged from top to bottom. The time domain magnetic and electric hybrid transmission source is adopted for transmission, the array type magnetic sensor is adopted for reception and the electric sensor is adopted for reception, so that the source distance of the detector is shortened, and the borehole far detection is realized.

The present application relates to a kind of system response correction methods of time domain electromagnetic detection system.The present application method is used to correct the influence of system response on effective signal, removes the influence of inherent characteristics of receiving sensor on effective signal by training adaptive output compensation of the theoretical and actual response of correction device;And by the real measured current waveform and adaptive current sensor compensation, the real transmitting current waveform is obtained, and the response of earth under unit step excitation is obtained according to its inverse function.The present application can remove the influence of system response on time domain electromagnetic detection system signal, improve signal quality, reduce the blind area time of system detection, improve the detection range of system.

The present application relates to the technical field of geophysical electromagnetic data exploration, in particular to a three-dimensional time-frequency domain electromagnetic joint inversion method based on finite element algorithm. The method obtains time domain and frequency domain electromagnetic observation data of the region to be measured respectively; the region to be measured is profiled to obtain a non-structural tetrahedral mesh to construct a time-frequency domain inversion initial model; the time-frequency domain inversion initial model is forward calculated to obtain time domain and frequency domain electromagnetic response data; time domain electromagnetic data residuals and frequency domain electromagnetic data residuals are obtained, and their corresponding adaptive weights are obtained respectively to establish a joint inversion objective function; the joint inversion objective function is iteratively solved to calculate the update vector of the inversion initial model; the inversion initial model is iteratively updated until the set condition is reached, and the time-frequency domain electromagnetic joint inversion is completed. The present application effectively improves the accuracy of three-dimensional inversion through joint inversion, thereby enhancing the practical effect of three-dimensional inversion.

The invention discloses a large-loop source transient electromagnetic fast forward modeling method based on GPU acceleration, and the method comprises the steps: firstly carrying out the parameter setting and preprocessing, then segmenting a large-loop source into a north edge, a south edge, an east edge and a west edge, and carrying out the discretization of each edge into N electric dipoles through employing a Gaussian-Legendre quadrature method; constructing a loop edge-frequency sampling point-wave number-time channel four-level parallel computing architecture to compute each edge; wherein each side in the GPU adopts a frequency-wave number-time parallel computing architecture, and parallel computing is performed on each electric dipole, so that the frequency-time domain response of each electric dipole is obtained; and finally, after calculation of all the electric dipoles is completed, vectorization calculation and summation are carried out on transient responses of all the electric dipoles on the GPU, a large loop source total field response at the current observation point is obtained, and a final time domain electromagnetic field value is output. According to the method, the advantages of large-scale parallel computing of the GPU can be efficiently and fully played, so that the computing efficiency is effectively improved on the premise of ensuring the computing precision.

The application relates to a time-domain electromagnetic space-time double-gradient resistivity imaging method, device, computer equipment, computer readable storage medium and computer program product. The method comprises the following steps: acquiring transient electromagnetic method data to be processed, wherein the data to be processed comprises electric field component attenuation data of m*n measuring points, and a far zone condition is met between the m*n measuring points and a long wire source; acquiring a spatial gradient expression of apparent resistivity and a time gradient expression of apparent resistivity; performing finite difference fusion based on the spatial gradient expression of resistivity and the time gradient expression of apparent resistivity to obtain a gradient resistivity expression; and generating a resistivity distribution map of a subsurface medium according to the data to be processed and the gradient resistivity expression. The abnormal body boundary description accuracy is improved.

The application discloses a data storage method of time domain electromagnetic signals, comprising the following steps: initiating a transfer transaction from a sending account to a receiving account of a block chain transfer transaction, and placing time domain electromagnetic signal data in a parameter input area; performing a transfer operation to complete the on-chain storage of the time domain electromagnetic signal data. The data storage method of the time domain electromagnetic signals on the block chain chain based on the transfer transaction writes the time domain electromagnetic signal data in the form of the transfer transaction into the block chain through the decentralized idea, thereby avoiding the phenomenon of "super-privilege user tampering" of the centralized storage, and improving the security and reliability of the time domain electromagnetic signal data storage.

The present disclosure belongs to the technical field of geophysical exploration signal processing, and particularly relates to a time-domain electromagnetic polarization parameter extraction method based on an improved physical guided neural network, comprising generating a sample set; constructing a loss function constrained by physical information; using the sample set, minimizing the loss function, and using an improved whale optimization algorithm to optimize the hyperparameters of the neural network to obtain a time-domain electromagnetic polarization parameter neural network inversion model; wherein the improved whale optimization algorithm introduces chaotic mapping to generate an initial population in the initialization stage, introduces a dynamic opposite learning strategy in the bubble net attack stage, and introduces an adaptive t-distribution disturbance variation in the search prey stage; obtaining measured data and preprocessing the same, using the time-domain electromagnetic polarization parameter neural network inversion model to process the preprocessed measured data, and extracting polarization medium model parameters. The method improves the accuracy and robustness of polarization parameter interpretation.

This invention discloses a rapid detection method for shallow ore bodies based on the fusion of time-domain electromagnetic method and AI, comprising: acquiring time-domain electromagnetic induction data of each unit within the detection area and extracting voltage decay curves to obtain preliminary ore body electromagnetic response characteristics; analyzing electromagnetic signal abrupt change points between adjacent units based on the preliminary ore body electromagnetic response characteristics to determine ore body boundary location information; processing the ore body boundary location information using a clustering algorithm to generate a three-dimensional geological structure model; obtaining clear electromagnetic response signals based on the three-dimensional geological structure model; identifying aliased electromagnetic response components in overlapping areas based on the clear electromagnetic response signals to determine existing ore body structures; when multiple ore body structures are determined to exist, acquiring response components and decomposing them into independent electromagnetic signal components using a signal separation algorithm to obtain time constant difference characteristics of each ore body; constructing location modeling relationships based on the time constant difference characteristics and generating a spatial distribution map of overlapping ore bodies.

The invention discloses a machine learning-based time domain electromagnetic transmitter performance evaluation method, which comprises the following steps of: extracting key parameter data from an operation log of an electromagnetic transmitter, and preprocessing the key parameter data to obtain a standardized data set; constructing a multi-dimensional feature set according to the standardized data set, and dividing the multi-dimensional feature set into an input feature vector and a target output variable; training a regression prediction model according to the multi-dimensional feature set to obtain a trained performance prediction model; and predicting the to-be-evaluated data according to the performance prediction model to obtain a prediction result, and performing feature importance analysis on the prediction result to obtain an analysis result. According to the method, intelligent evaluation of transmitter performance under the conditions of multiple devices and multiple working conditions can be achieved, the limitation of a traditional experience or single-index method is overcome, the precision and interpretability of performance analysis are improved, and a new data driving scheme is provided for instrument operation optimization and abnormality diagnosis.

The application discloses a GPU acceleration-based large-loop-source transient electromagnetic fast forward method, which comprises the following steps: firstly, parameter setting and pretreatment are performed; then, the large-loop-source is divided into four edges of north, south, east and west, and each edge is discretized into N electric dipoles by using a Gauss-Legendre quadrature method; a four-level parallel computing architecture of loop edge-frequency sampling point-wave number-time channel is constructed to calculate each edge; wherein, the parallel computing architecture of frequency-wave number-time is used in each edge in the GPU to perform parallel calculation on each electric dipole, so that the frequency-time domain response of each electric dipole is obtained; finally, after the calculation of all electric dipoles is completed, the vectorization calculation and summation of the transient responses of all electric dipoles are performed on the GPU to obtain the total field response of the large-loop-source at the current observation point, and the final time domain electromagnetic field value is output. The above method can efficiently and fully exert the large-scale parallel computing advantage of the GPU, so that the calculation efficiency is effectively improved under the premise of ensuring the calculation precision.

The invention discloses a shallow ore body rapid detection method based on fusion of a time domain electromagnetic method and AI, and the method comprises the steps: obtaining time domain electromagnetic induction data of each unit in a detection region, and extracting a voltage attenuation curve to obtain initial ore body electromagnetic response features; analyzing electromagnetic signal mutation points between adjacent units based on the preliminary ore body electromagnetic response characteristics, and determining ore body boundary position information; processing the ore body boundary position information by adopting a clustering algorithm to generate a three-dimensional geologic structure model; obtaining a clear electromagnetic response signal based on the three-dimensional geological structure model; on the basis of the clear electromagnetic response signals, aliasing electromagnetic response components in the overlapping area are identified, and an existing ore body structure is determined; when it is judged that multiple ore body structures exist, response components are obtained and decomposed into independent electromagnetic signal components through a signal separation algorithm, and time constant difference characteristics of all ore bodies are obtained; and constructing a position modeling relation based on the time constant difference characteristics, and generating an overlapped ore body spatial distribution diagram.

The invention discloses an induction-polarization effect targeted excitation method based on full-waveform current control, and aims to respectively excite a polarization effect and an induction effect of an underground medium in a targeted manner by using a slow-rising and fast-turn-off combined emission current so as to realize high-precision detection. A polarization model is constructed based on geological data, optimal current parameters including rise time, fall time and the like are calculated, and target excitation parameters are preset in the master controller; aiming at a polarization effect, linear slow rising excitation of emission current is realized based on a direct current voltage regulation clamping module, and observation is carried out at a flat top section; and aiming at the induction effect, linear fast turn-off excitation of emission current is realized based on the energy feedback voltage regulation clamping module, and observation is carried out at the tail section after the current is completely turned off. According to the invention, in a unipolar period, the time domain electromagnetic response of the induction effect and the polarization effect is enhanced in a targeted manner, and the conductive and polarization information is obtained at the same time, so that the signal-to-noise ratio of polarization data and the exploration efficiency are improved, and time domain electromagnetic refined exploration is facilitated.

The embodiments of the present application relate to the field of geophysical electromagnetic data processing, and specifically to a method for frequency-domain conversion of magnetic source time-domain electromagnetic data at a specified measuring point in a specified work area, comprising the following steps: S1: determining a typical resistivity value of the specified work area based on the specified work area; S2: acquiring time-domain electromagnetic data at a specified measuring point in the specified work area to determine a time trace vector and an induced electromotive force vector; S3: determining a random resistivity vector of the specified work area based on the typical resistivity value; S4: determining a calculated induced electromotive force vector based on the random resistivity value vector and the time trace vector; S5: determining fitness based on the calculated induced electromotive force vector and the induced electromotive force vector; S6: determining an optimal resistivity vector based on the fitness and a fitness threshold; and S7: calculating the frequency-domain electromagnetic response of the magnetic source based on the optimal resistivity vector. The method provided by the embodiments of the present application can improve the accuracy and reliability of frequency-domain conversion.

The application belongs to the technical field of petroleum physical exploration, and particularly discloses a wellbore electric source time-domain electromagnetic measurement device and method. The device comprises a ground collection system, a cable, a remote transmission short section, an array electric source receiving sensor and a transmitting device. The ground collection system is connected with the remote transmission short section through the cable. The remote transmission short section is connected with the array electric source receiving sensor. The array electric source receiving sensor is connected with the transmitting device. The measurement mode of electric source excitation and array electric source receiving is adopted, the manufacturing process difficulty of three-dimensional magnetic source in the limited space of the wellbore is reduced, the problem of difficult quick shutdown of the multi-turn coil is solved, and the ultra-long detection of the radial geological information beside the well is realized.

This invention discloses a time-domain electromagnetic data removal method based on continuous wavelet transform, belonging to the field of time-domain electromagnetic noise processing technology. The method includes: acquiring accelerated transient electromagnetic signals; processing and superimposing averaging methods for accelerated transient electromagnetic signals; continuously performing time-frequency transform on the superimposed "total field" signal to obtain a wavelet coefficient matrix; performing dual filtering on the wavelet coefficients, including frequency filtering and amplitude filtering; performing continuous inverse time-frequency transform on the filtered wavelet coefficients to reconstruct the time-domain signal; applying amplitude enhancement processing to the reconstructed signal; and performing Gaussian smoothing processing on the enhanced time-domain signal to facilitate feature recognition. This invention is based on GPU-accelerated continuous wavelet transform + fast convolution. Wavelet transform has multi-scale analysis capabilities, realizing multi-scale decomposition of the signal in the time-frequency domain. Combined with band filtering and amplitude filtering, it performs targeted noise suppression, accurately suppressing specific frequency noise such as power frequency interference and harmonics.

The present application relates to the field of electromagnetic detection in geophysical exploration, in particular to a time-domain electromagnetic electric source transmitting system. The purpose is to achieve impedance matching of the electric source equivalent load and to effectively suppress the power ripple generated by the DC power bus. It includes a high-power DC power supply, a transmitting host and a fractional-order ripple suppression circuit, wherein the high-power DC power supply provides three-phase AC power; the transmitting host includes an H-bridge inverter circuit, which is connected to the transmitting cable and alternately conducts under the control of a set of complementary pulse width modulation signals to generate a transmitting current in the loop formed by the transmitting cable and the ground; the fractional-order ripple suppression circuit includes a matching capacitor and a first fractional-order device in series, which are connected in parallel at both ends of the H-bridge inverter circuit. It is beneficial to improve the performance of the time-domain electromagnetic electric source transmitting system.

The invention relates to the technical field of geological exploration, and particularly discloses a three-dimensional exploration method based on a composite field source, which comprises the following steps: S1, composite field source arrangement: arranging a plurality of different types of field sources in an observation system; s2, multi-field-source synchronous data acquisition: on the basis of acquisition by adopting a time domain electromagnetic method, performing supplementary measurement by using a frequency domain electromagnetic method; s3, data processing and joint inversion are carried out, data of different field sources are inversed respectively, a plurality of geophysical models which are possibly contradictory to each other can be generated, and a unified underground electrical structure model is searched through joint inversion; s4, performing result interpretation and verification, including comprehensive section compilation, three-dimensional geological modeling and drilling verification and correction; and S5, a final output result is obtained. The problems that a traditional electrical exploration excitation source is poor in adaptability and insufficient in detection performance, and complex requirements are difficult to meet are solved.

The invention discloses a transformer fault prediction method based on frequency domain and time domain combined feature extraction, and belongs to the technical field of power equipment fault diagnosis. The method comprises the following steps: firstly, synchronously acquiring a sweep frequency response curve and transient voltage and current recording data of a transformer; extracting frequency domain structure sensitivity features and time domain electromagnetic sensitivity features in parallel; fusing the different-source features to construct a high-dimensional joint feature vector, and performing dimensionality reduction by adopting principal component analysis; and finally, inputting the fusion feature vector into a pre-trained random forest machine learning model to realize joint recognition, severity evaluation and location positioning of the fault. Through complementation of frequency domain and time domain features, the problems that an existing method depends on a single signal type, is not sensitive to early faults and is difficult to identify multiple fault types at the same time are solved, and the accuracy rate and the early warning capacity of transformer fault diagnosis are remarkably improved.

The invention discloses a time-domain electromagnetic coupling calculation method and device, electronic equipment and a storage medium, and relates to the technical field of electromagnetic fields. Compared with the prior art, a multi-conductor transmission line system is divided into cascaded transmission line units, and an external electromagnetic field horizontal component is equivalent to a transverse voltage source; an improved telegraph equation is established in combination with a pre-training field line coupling model, a multi-port Norton equivalent circuit is constructed after modulus conversion, the structure is simplified by utilizing the characteristics of a short-circuit admittance matrix, the ultra wide band and strong transient characteristics of high-altitude electromagnetic pulses can be adapted, and the complexity of the model is reduced. The technical problems that in an existing field line coupling modeling method, due to the fact that a distributed voltage source equivalent strategy is adopted, model complexity is high and computing resource consumption is large under high-altitude electromagnetic pulse excitation can be solved, and the purposes that the complexity of a multi-conductor transmission line system field line coupling model is reduced, computing resource consumption is reduced, and the modeling efficiency is improved are achieved. And the coupling modeling efficiency in the extreme electromagnetic environment is improved.