51 results about "Transient waves" patented technology

The invention discloses a welding robot track self-adaptive correction method based on multi-modal data fusion, and particularly relates to the technical field of industrial robots, which comprises the following steps: synchronously acquiring visual three-dimensional point cloud and arc current and voltage transient waveform data in a welding process in real time; an enhanced working trajectory feature vector fusing the visual trajectory features and the arc deviation compensation amount is constructed; respectively calculating real-time confidence coefficients of the visual sense and the arc sensing mode; inputting the confidence coefficient into a weight distribution strategy model, dynamically resolving vision and arc weight coefficients, and when the confidence coefficient of one sensor is low, lifting the weight of the other sensor to dominate correction; performing weighted fusion on the two pose adjustment amounts by using a weight coefficient to generate a six-degree-of-freedom comprehensive trajectory correction amount; and finally, the robot is driven to execute online adaptive trajectory correction. Through a confidence-driven dynamic fusion strategy, the limitation of a single sensor is overcome, and the welding robot trajectory tracking precision and the adaptive capacity are improved.

The invention provides a transient recording fault intelligent judgment method combining waveform matching and cloud edge cooperation, and relates to the technical field of fault diagnosis. Comprising the following steps: collecting global topological information and fault judgment reference parameters of a master station synchronous power system, and outputting initial transient recording data; carrying out preprocessing and feature extraction on the initial transient recording data, realizing edge side layered fault detection by adopting an improved waveform matching algorithm, and outputting multi-layer fault information; constructing a global fault judgment model, updating the global fault judgment model through the hierarchical model, and optimizing the fault judgment model; multi-level fault information is input into the optimized fault judgment model for accurate fault judgment, and graded response measures are taken for real-time judgment results with different confidence degrees; according to the invention, through deep fusion and system-level optimization of multiple technical streams, a transient recording fault intelligent judgment system integrating real-time performance and accuracy is created.

The invention relates to the technical field of intelligent decision making, can be applied to business system platforms of financial science and technology, medical health and the like, and discloses an equipment adaptive control method and device, equipment and a medium, and the method comprises the following steps: obtaining a multi-modal signal of an equipment detection target, and constructing a dynamic reference system according to the multi-modal signal; performing space-time alignment optimization on the multi-modal signal according to the dynamic reference system to obtain a space-time alignment signal, and performing dynamic calibration on the space-time alignment signal to obtain a calibration signal; performing transient waveform distortion feature extraction on the calibration signal to obtain a signal distortion feature; performing feature space mapping on the signal distortion features to obtain a feature mapping result; and generating an equipment early warning grade parameter according to the feature mapping result and a preset safety boundary distance, and dynamically adjusting a preset equipment control parameter according to the equipment early warning grade parameter. By analyzing the multi-mode signal, the dynamic adjustment of the equipment control parameters is realized, and the equipment detection precision is improved.

The invention discloses a simulation IC test method and system based on load transient response, and aims to improve the performance evaluation precision of a simulation IC under a complex load condition. The method comprises the following steps: firstly, acquiring transient response waveforms and response delay characteristics of an analog IC (Integrated Circuit) in various load jump modes, and constructing a mapping matrix between a load current step change rate and response delay time; in the real-time test, response delay time in a future preset time period is predicted according to the step change rate of the current load current. When the steady-state time window exists, a fixed sampling time sequence is set based on the window to generate a first test waveform; and if the steady-state window does not exist, correcting the transient waveform, and generating a compensated second test waveform. And then time sequence decomposition is carried out on the test waveform, and a load transient stability evaluation matrix is constructed, so that the dynamic performance of the simulation IC is accurately evaluated, and a detailed performance test report is output.

The invention relates to the technical field of semiconductor device measurement, and provides a semiconductor nonlinear output junction capacitance measurement method based on fitting iteration, and the method comprises the steps: firstly building a junction capacitance extraction circuit, collecting the turn-off transient waveform of a to-be-measured device through a test platform, extracting the oscillation frequency fexp through fast Fourier transform, and carrying out the measurement of the to-be-measured device; based on the relation between the oscillation frequency and the junction capacitance and parasitic parameters, the initial junction capacitance Coss is reversely deduced; then, fitting is carried out by adopting a hyperbolic tangent function, fitting parameters are optimized through a least square method, a preliminary junction capacitance Coss-test voltage udc relation curve under different voltage grades is obtained, an oscillation frequency simulation circuit is further built, simulation frequency fm is obtained, fm is compared with fexp, if deviation exists, the fitting curve is adjusted and iterative optimization is carried out, and the test voltage udc relation curve of the junction capacitance under different voltage grades is obtained. And ending until the error of two adjacent rounds of fitting results is lower than a set error threshold value, thereby obtaining a final accurate junction capacitance Coss-test voltage udc relation curve.

The invention discloses a high-speed link signal integrity analysis general modeling method and system based on fast time domain simulation and transfer learning. The method comprises the following steps: S1, selecting a high-speed link structure to be modeled; s2, extracting a pure edge signal without intersymbol interference based on a multi-edge response method, and calculating a reconstructed transient waveform and a worst eye pattern; s3, only performing a small amount of high-precision transient simulation and preprocessing in the target domain, and constructing a target domain data set; s4, designing special neural network DNN and TCN models, and constructing a source domain data pre-training model by using source domain fast time domain simulation data; and S5, based on a transfer learning strategy, the model is finely tuned by using limited target domain data. The method is used for constructing the high-speed link signal integrity agent model, so that under the condition that the number of times of high-precision transient simulation is remarkably reduced, the model prediction precision and training efficiency are improved, and the problems that traditional transient simulation consumes too long time, ANN model data dependence is large, and the transfer learning application range is limited are solved.

The invention discloses an intelligent early warning system for an industrial safety production situation, particularly relates to the field of industrial network safety, and is used for solving the problems of real-time splicing of hidden abnormal sequences and quantification of cross-subnet dangerous potential energy in an industrial network in which variable topology and hidden channels coexist. Tracking the whole network dynamic state; the transient waveform is decomposed by a multi-scale wavelet packet to form a micro-impact fingerprint index, and abnormity is accurately detected; calculating a time slot compression potential and an energy jump amplitude in combination with gap virtual node interpolation and energy vector interpolation, and identifying hidden threats in a time domain and an energy domain respectively; extracting an intersection criticality through double logarithmic spiral mapping, driving a multi-body energy diffusion model, and drawing a danger potential value propagation gradient in real time; through comparison of the risk matrix and the dynamic inflection point criterion, the early warning advance and the coverage subnet range are significantly improved, the linkage trigger chain outbreak is avoided, the anomaly recognition sensitivity is improved, the link repair period is shortened, and the false alarm rate is reduced.

The invention relates to the technical field of reliability testing of semiconductor power devices, and discloses a short-circuit robustness testing method and system based on grid stress degradation of a silicon carbide device, and the method comprises the steps of pre-testing short circuit, grid stress application and post-testing short circuit are continuously executed under the same physical connection by configuring a coupling testing time sequence. The control unit cooperates with the driving unit to generate a static positive and negative bias and dynamic switch stress mode, and cooperates with the power loop auxiliary switch action to simulate different short circuit faults. A dynamic and static index correlation model is established to quantitatively evaluate robustness by collecting transient waveforms and measuring static parameters and calculating short-circuit energy integral, threshold voltage and drift distance of on resistance. According to the invention, the in-situ test of the aging and short-circuit characteristics of the device is realized, the contact resistance change and the loop parasitic parameter difference caused by the repeated disassembly and assembly of the device in the traditional discrete test are eliminated, and the change of the two short-circuit waveforms completely corresponds to the internal degradation of the device caused by the grid stress.

The invention discloses a grid drive short-circuit protection method based on dV / dt detection, which relates to the technical field of power electronics, and comprises the following steps: constructing a unified time frequency reference baseline, executing all-phase mapping on each power device of a parallel system, reconstructing a conduction sequence, and calculating a phase difference between a voltage rising edge and sampling trigger. Generating a time frequency dislocation matrix, and determining a phase dislocation risk window; and executing causal playback in the phase dislocation risk window, extracting transient waveform characteristics of a voltage rising edge, eliminating parasitic pseudo peaks, obtaining an effective response trajectory, generating a sampling phase check anchor point based on the trajectory, and constructing a phase reference baseline. According to the method, a unified time-frequency baseline and a dynamic sampling mechanism are constructed to realize phase synchronization of sampling and conduction, the sampling rhythm and the turn-off threshold are optimized in combination with feed-forward vibration suppression and residual adjustment, the short circuit identification speed and precision are improved, and the method has self-healing and self-correcting capabilities and is suitable for high-frequency and high-power density scenes.

The invention relates to the field of power system state monitoring, and discloses a power equipment fault diagnosis system suitable for a complex power grid environment, and the system comprises a propagation medium model building unit which is used for dynamically correcting a model through benign transient waves; the transient traveling wave synchronous acquisition unit is used for synchronously acquiring traveling wave data at high precision; the fault positioning unit is used for determining a fault position based on a time difference residual minimization principle; and the fault property and equipment state analysis unit is used for carrying out deep analysis by comparing actually measured and theoretical reflected wave path spectrums and frequency dispersion characteristics. The method comprises the following steps: constructing and dynamically correcting a transient wave propagation medium model; synchronously acquiring transient traveling waves excited by an electrical event; calculating a fault physical position; the propagation characteristics of the transient waves are analyzed to determine fault properties and device states. According to the invention, the electrical asymmetry hidden danger can be identified and positioned by actively injecting the pure-sequence traveling wave probe, and the combination of passive diagnosis and active early warning is realized.

The embodiment of the invention provides a power loop dynamic VI calibration method, system and device and a storage medium, and the method comprises the steps: carrying out the real-time detection of a half-bridge circuit, obtaining a detection value, and obtaining first detection time and second detection time through combining with a second preset condition and a third preset condition; the switching state is identified by comparing the first detection time and the second detection time, and dynamic voltage-current (VI) calibration is achieved with a first time offset by capturing a first turn-off transient waveform and a second turn-off transient waveform and calculating the first time offset in a fast switching transient. According to the embodiment of the invention, by accurately analyzing the relation between the current and the voltage in the switching transient process, the measurement error caused by high-frequency noise and time deviation in the traditional voltage-current (VI) calibration is effectively avoided.

The invention relates to a balun MMIC power amplifier, a broadband testing device and a broadband testing method.The balun MMIC power amplifier comprises a 1: 1 balun differential circuit, an MMIC power amplifier body and a 1: K balun differential circuit, and the problem of high-frequency current signal amplification is solved; the broadband testing method comprises the following steps: carrying out steady-state wave testing on the current transformer to be tested through the broadband testing device; carrying out transient wave testing on the current transformer to be tested through the broadband testing device; and testing the traveling wave positioning function of the current transformer based on the traveling wave head, testing the accuracy of the traveling wave fault positioning function of the current transformer to be tested, and generating a traveling wave positioning function test report. Based on the application of a Balun MMIC power amplifier and the optimization of a test process, the invention aims to solve the key problems in the prior art, improve the accuracy and comprehensiveness of the broadband test of the current transformer, and meet the urgent demand of a power system for the accurate evaluation of the performance of the current transformer.

The invention discloses a meshless Galerkin-Newmark method for calculating a transient wave propagation problem. The meshless Galerkin-Newmark method comprises the following steps: dispersing a transient wave propagation problem domain into nodes; selecting an interpolation primary function and a weight function; constructing a node interpolation primary function and a global interpolation format by adopting a moving least square method based on the selected function; based on a global interpolation format, combining a partial differential control equation and a Galerkin weighted residual value method to obtain a transient wave propagation problem system matrix equation; performing time domain discretization through a Newmark time integration method to obtain a discrete time equation; solving the discrete time equation to obtain a numerical calculation result; and analyzing a result and comparing the result with a common method to finish solving and analyzing a transient wave propagation problem. The meshless Galerkin-Newmark method for calculating the transient wave propagation problem has a monotonous consistent convergence characteristic in the numerical calculation of the transient wave propagation problem, and the calculation precision can be continuously improved along with the reduction of the time integral step length.

The application discloses an enhanced mobile least square meshless-Newmark integral method for reducing total dispersion error of transient wave propagation, and belongs to the technical field of numerical analysis and total dispersion error prediction of transient wave propagation, and comprises the following contents: a wave propagation problem domain is discretized into a series of nodes; a standard mobile least square interpolation base function of each node is derived; a local numerical approximation of an enhanced least square algorithm is completed; a global interpolation format of a general scalar field based on the enhanced least square algorithm is constructed; a system matrix equation of the dispersion analysis of the transient wave propagation problem is obtained by adopting a Galerkin weighted residual method and a Newmark time integral method; and based on a given node distribution, the total dispersion error of different calculation methods along different wave propagation directions under different time integral step lengths is calculated. The application adopts the above method, reduces the total dispersion error caused by the coupling of spatial dispersion and time dispersion, and improves the solving precision.

This invention relates to the field of semiconductor device measurement technology, and proposes a method for measuring the nonlinear output junction capacitance of semiconductors based on fitting iteration. This method first constructs a junction capacitance extraction circuit, and then acquires the turn-off transient waveform of the device under test through a test platform. Finally, it uses Fast Fourier Transform to extract the oscillation frequency f. exp Based on the relationship between the oscillation frequency, junction capacitance, and parasitic parameters, the initial junction capacitance C is deduced. oss Subsequently, a hyperbolic tangent function was used for fitting, and the fitting parameters were optimized using the least squares method to obtain the preliminary junction capacitance C under different voltage levels. oss - Test voltage u dc Based on the relationship curve, a simulation circuit for the oscillation frequency was further constructed to obtain the simulation frequency f. m and f m with f exp The fitting curve is compared, and if a deviation exists, the fitting curve is adjusted and iteratively optimized until the error between two adjacent fitting results is lower than the set error threshold, thus obtaining the final accurate junction capacitance C. oss - Test voltage u dc Relationship curve.

The utility model discloses a multifunctional earth screen monitoring device which at least has the following beneficial effects: a power supply module; the control module is connected with the power supply module; the intelligent analysis module is connected with the control module, and the intelligent analysis module is used for obtaining the peak value, the wave head time, the wave tail time and the gradient of the lightning stroke current; and the lightning stroke current detection module is connected with the intelligent analysis module, and the lightning stroke current detection module is arranged on the earth screen main line and is used for obtaining the transient waveform of the lightning stroke current. According to the technical scheme of the embodiment, the lightning stroke type and the corrosion degradation trend of the ground screen can be effectively judged.

The application relates to the technical field of optical element testing, and discloses a fiber connector butt joint position deviation detection method and system. The method first performs physical butt joint on a standard reference jumper fiber, collects a static reference insertion loss value and a transient Fresnel reflection dithering waveform of a butt joint full cycle, extracts an end face structure scattering entropy, and constructs a multi-dimensional optical transmission characteristic reference library; then real-time transient waveforms of on-site butt joint are collected and real-time scattering entropy is calculated, feature matching is performed, decoupling branch determination of end face physical defects and mechanical geometric position deviation is completed, and a to-be-corrected optical link data packet is generated according to the position deviation; finally, a connection point characteristic signal is obtained through iterative deconvolution signal reconstruction, three-dimensional position deviation is analyzed, and a correction instruction is generated to perform closed-loop verification; the application effectively avoids end face damage caused by end face defect misjudgment, and realizes high-precision detection and adaptive correction of butt joint position deviation.

The utility model discloses a selection circuit, an emission power supply and ultrasonic equipment, and solves the problem of different emission current demands in different imaging modes. According to the scheme, in the shear wave imaging mode, the resistance value is small when the shear wave path is conducted, so that large transient wave beam energy is provided for the transmitting circuit; in a conventional imaging mode, such as a conventional PW or Color mode, the resistance value of a conventional path is large, at the moment, relatively small energy is provided for the transmitting circuit, and the transmitting requirement in the conventional imaging mode can be met. In conclusion, through switching of the shear wave path and the conventional path, efficient transmission of appropriate emission current and emission energy in different imaging modes is achieved, the current requirements in the shear wave imaging mode and the conventional imaging mode are met at the same time, and the adaptability and performance of the switching power supply are improved.

The invention discloses a traveling wave / transient state quantity protection method and system for an electric power system and electrical equipment, and terminal equipment. A bypass attenuation effect of a bus stray distribution capacitor on a fault traveling wave / high-frequency transient quantity or a hindering effect of reactance of electrical equipment on the fault traveling wave / high-frequency transient quantity, a refraction and reflection effect of the fault traveling wave / high-frequency transient quantity at a wave impedance discontinuous point and a shunting effect at a branch, and a hindering effect of a wave trapper on a specific frequency band are utilized; the internal relation between the difference value and the average value of the observed values at the two different monitoring points is utilized, the relative gradient or gradient or kurtosis or relative kurtosis or gradient or relative gradient is utilized to calibrate the initial effective action period of the fault traveling wave / transient quantity, and traveling wave / transient quantity protection is constructed. According to the method, the initial effective action period of the fault transient quantity, the effective action period of the fault traveling wave head and the arrival time of the fault traveling wave head are accurately calibrated, and the problem that the arrival time of the traveling wave head cannot be accurately calibrated by traditional transient / traveling wave protection is solved.

The application discloses a kind of generator rotor winding dynamic ground fault multi-modal diagnostic system and method, belong to generator state monitoring and fault diagnosis technical field, in system, leakage current sensing module can collect the transient waveform of rotor winding leakage current to ground;Multi-physical quantity can synchronous acquisition module collects rotor voltage ripple signal and shaft vibration acceleration signal;Ground capacitance online measurement module can be under the working condition of generator rotation, acquisition rotor dynamic ground capacitance value;Signal processing and diagnosis host computer can carry out time-frequency analysis and data fusion to the signal received, construct leakage current-shaft vibration-voltage ripple three-dimensional fault fingerprint matrix, and then realize early fault identification, fault location, fault nature evaluation and rotor winding insulation state classification.The application fuses multi-modal information, resists strong electromagnetic interference, realizes early warning of dynamic ground fault, early identification of dynamic ground fault and accurate positioning and nature identification of insulation deterioration point.

The invention relates to a dynamic monitoring and early warning method, system and terminal for sedimentation of a sewage and rain pipe network, and relates to the technical field of urban drainage pipe network monitoring, and the method comprises the steps: actively generating a pressure transient wave at a monitoring point of the pipe network, and enabling the pressure transient wave to be transmitted in the pipe network; echo signals generated when the pressure transient waves are propagated in the pipe network are collected, and a pressure time sequence containing geometric structure information in the pipe network is formed; performing reverse reconstruction calculation on the pressure time sequence based on a preset pipe network hydraulic physical model to obtain a continuous deposition profile of a downstream pipe section of the monitoring point; and according to the continuous siltation profile, the siltation state of the pipe network is evaluated, and an early warning signal is generated when the siltation state meets a preset condition. According to the application, the problem that in the prior art, on the premise that normal operation of the pipe network is not interrupted, the effects of remote, automatic and accurate positioning, quantitative evaluation and dynamic early warning on pipe network siltation are difficult to achieve are solved.

The invention discloses a transformer on-load tap-changer testing method and testing device based on alternating current and direct current characteristics, and relates to the technical field of power equipment detection.The testing method comprises the steps that in response to adjustable direct current voltage applied to an on-load tap-changer, direct current resistance values at all tapping positions are measured, and direct current resistance deviation is calculated; the method comprises the following steps: in response to a sweep frequency alternating current signal injected into an on-load tap-changer in a preset frequency range, acquiring voltage and current transient waveforms at the moment of switch action, and calculating a sweep frequency impedance phase angle and arc energy intensity and contact jitter variance in the transient waveforms; the direct current resistance deviation, the sweep frequency impedance phase angle, the arc energy characteristic and the contact jitter variance form a fusion characteristic vector; and inputting the fusion feature vector into a pre-trained deep belief network diagnosis model, and outputting fault probability distribution. According to the invention, the operation state information of the on-load tap-changer can be comprehensively obtained from multiple dimensions, and the fault of the on-load tap-changer of the transformer can be accurately diagnosed.

The invention provides a method for calculating a ship motion response amplitude operator, which comprises the following steps of: generating a transient wave packet based on a specified wave spectrum, carrying out a target ship type seakeeping model test by adopting the transient wave packet, and extracting a time sequence of the transient wave packet and a time sequence of ship model swaying motion; wherein the time sequence of the transient wave packet needs to be collected when no ship model exists in a water pool, a Hilbert marginal spectrum analysis model based on Hilbert-Huang transform is established, and the time sequence of the transient wave packet and the time sequence of the ship model swaying motion under the action of the transient wave packet are input into the Hilbert marginal spectrum analysis model. The method comprises the following steps of: acquiring a transient wave packet time sequence, acquiring a marginal spectrum of the transient wave packet time sequence and the ship model swaying motion time sequence, and acquiring a target ship swaying motion response amplitude operator according to a ratio of the ship model swaying motion time sequence to the marginal spectrum of the transient wave packet time sequence. And therefore, the problem that a ship motion response amplitude operator curve has a relatively large error can be solved.

The invention provides an underwater target time domain transient feature intelligent detection method based on a convolutional neural network. The method comprises the following steps: firstly, constructing a one-dimensional time domain waveform sample set with transient label information; secondly, designing a multi-scale convolution operator on the basis of a deep convolutional neural network method in combination with underwater acoustic target transient characteristic knowledge, and constructing a deep neural network detection model on the basis of the multi-scale convolution operator; then designing a transient waveform value reinforcement learning loss function and completing deep neural network detection model training based on the sample set; and finally, processing unknown target data based on the deep neural network detection model, and outputting a transient behavior detection result. According to the method, a deep neural network is constructed, a weak feature reinforcement learning method is designed, the comprehensiveness and the refinement degree of feature information mining and utilization are improved, and the method is an innovative method for application of an artificial intelligence algorithm in the field of underwater acoustic signal processing.

The invention discloses a physical information neural network solving method and system for shaft transient fluctuation pressure. The method comprises the steps that a physical control equation and definite solution conditions are constructed based on fluid dynamics; obtaining training data and normalizing the training data; a physical information neural network with a hard-soft constraint coupling mechanism is constructed, hard constraint compulsively meets an initial boundary value condition through structural transformation, and soft constraint constructs joint loss based on equation residual errors and data errors; introducing an adaptive loss weight and an adaptive activation function configuration model; training the model to convergence by using the data and the joint loss; and inputting to-be-measured coordinates and outputting a pressure field. According to the method, accurate satisfaction of physical boundary conditions is ensured through hard-soft constraint coupling, the capture capability and convergence precision of the model on transient shock wave characteristics are improved by using an adaptive optimization mechanism, effective fusion of a physical mechanism and data is realized, and the calculation efficiency is improved.

The application relates to the field of power system state monitoring, and discloses a power equipment fault diagnosis system suitable for a complex power grid environment, which comprises a propagation medium model construction unit, a transient traveling wave synchronous acquisition unit, a fault positioning unit and a fault property and equipment state analysis unit. The propagation medium model construction unit is used for dynamic correction of a benign transient wave. The transient traveling wave synchronous acquisition unit is used for high-precision synchronous acquisition of traveling wave data. The fault positioning unit is used for determining a fault position based on a time difference residual minimization principle. The fault property and equipment state analysis unit is used for deep analysis by comparing a measured reflection wave path spectrum and a theoretical reflection wave path spectrum and by comparing frequency dispersion characteristics. The method comprises the following steps: constructing and dynamically correcting a transient wave propagation medium model; synchronously acquiring transient traveling waves excited by electrical events; calculating a fault physical position; and analyzing propagation characteristics of the transient traveling waves to determine a fault property and an equipment state. The application can also identify and position electrical asymmetry hidden dangers by actively injecting a pure positive sequence traveling wave probe, and realizes the combination of passive diagnosis and active early warning.

The invention discloses an upper limb exoskeleton intention recognition method and system based on myoelectricity and a neural network. The method comprises the steps that a sensor is used for synchronously collecting an upper limb original myoelectricity signal sequence and an inertial kinematics sequence; performing action phase coarse segmentation by taking the inertial sequence as a reference, calculating an energy sequence by utilizing a nonlinear energy operator, eliminating invalid resting signals in combination with dual-threshold judgment logic, and generating a time sequence characteristic sample sequence through sliding window processing; calculating a root mean square value and an envelope slope feature of each channel to construct a time sequence feature matrix; a causal convolution layer is utilized to extract transient waveform features which only depend on historical information, a time sequence dependency feature is extracted through an LSTM layer, an envelope slope feature is injected into an attention mechanism to enhance the capture capability of an action boundary, and finally contraction, hovering and extension intentions are identified. The problems of electromechanical delay and hovering misjudgment are effectively solved, and the real-time performance and accuracy of exoskeleton control are improved.

The application relates to a laser ultrasonic signal processing method for a double-wave mixing interferometer, which comprises the following steps: acquiring a laser ultrasonic time domain signal received by the double-wave mixing interferometer; performing discrete wavelet decomposition on the laser ultrasonic time domain signal to obtain layer detail coefficients and approximation coefficients; determining adaptive threshold values for the layer detail coefficients based on unbiased risk estimation, and performing smoothing processing on the layer detail coefficients; performing inverse wavelet transformation and reconstruction on the smoothed detail coefficients and the reserved approximation coefficients to obtain a reconstructed signal; constructing a digital band-pass filter with maximum flat characteristics of a passband based on the frequency spectrum distribution of a target ultrasonic characteristic wave to be extracted; and extracting a target ultrasonic characteristic signal by using the digital band-pass filter. The adaptive soft threshold algorithm of wavelet decomposition and unbiased risk estimation can completely eliminate the signal artifacts and additional oscillations of a hard threshold value, and perfectly reserve the weak and key transient wave peaks and amplitude characteristics of an ultrasonic longitudinal wave.

The application discloses a wave front detection system and method based on a pulse camera, and belongs to the technical field of adaptive optics. The system comprises a micro optical unit for dividing an incident wave front into a sub-spot array; a pulse camera, whose photosensitive surface is located at the focal plane of the micro optical unit, for receiving the sub-spot array and outputting spot change information in the form of an asynchronous pulse stream; and a data processing unit for processing the pulse stream in real time, outputting a transient wave front phase through pulse classification, centroid calculation and wave front reconstruction. The application utilizes the high time resolution and asynchronous output characteristics of the pulse camera, can track the high-speed movement of a spot with a precision of microseconds, significantly improves the time resolution and dynamic range of wave front detection, and is suitable for fields such as astronomical observation, high-speed flow imaging, laser communication and the like which require high-frequency and large-aberration measurement.