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1021 results about "Time–frequency analysis" patented technology
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In signal processing, time–frequency analysis comprises those techniques that study a signal in both the time and frequency domains simultaneously, using various time–frequency representations. Rather than viewing a 1-dimensional signal (a function, real or complex-valued, whose domain is the real line) and some transform (another function whose domain is the real line, obtained from the original via some transform), time–frequency analysis studies a two-dimensional signal – a function whose domain is the two-dimensional real plane, obtained from the signal via a time–frequency transform.
Pedestrian inertial positioning system based on indoor magnetic field feature assistance
ActiveCN103175529AThere is no need to lay out the problemReduce energy costsNavigation by terrestrial meansNavigation by speed/acceleration measurementsTime–frequency analysisAngular velocity
The invention provides a pedestrian inertial positioning system based on indoor magnetic field feature assistance. The system comprises a magnetic field and inertial data obtaining module, a magnetic field positioning module, a pedestrian dead reckoning module, a positioning fusion module and an output module, wherein the magnetic field and inertial data obtaining module is used for acquiring magnetic field, accelerated speed and angular velocity information; the magnetic field positioning module is used for building a magnetic field feature library and carrying out time-frequency analysis on the magnetic field vector sequence in real time to extract the time-frequency feature, and matching with the magnetic field feature library to carry out magnetic field feature positioning; the pedestrian dead reckoning module is used for updating accelerated speed and angular velocity zero offset according to the condition that the step velocity discontinuity is zero during walking, judging the step number and calculating the step length and the direction of each step; the positioning fusion module is used for fusing a magnetic field feature positioning result and a pedestrian dead reckoning inertial positioning result by means of particle filter; and the output module is used for displaying a positioning result on web pages and terminals. The system provided by the invention has the characteristics of being independent from beacon during positioning, low in cost and consumption of positioning terminals, accurate in positioning result and adaptive to environment change.
Owner:MEDIASOC TECH
Method of adaptive interactive learning control and a lithographic manufacturing process and apparatus employing such a method
InactiveUS20050043834A1Less potentImprove tracking performanceSemiconductor/solid-state device testing/measurementElement comparisonManufacturing technologyAdaptive filter
By applying time-frequency analysis to a given standard iterative learning control or ILC an adaptive filter for the learned feed-forward loop is designed. This time varying filter varies according to the momentary frequency content of the error signal and allows to discriminate between areas of deterministic and stochastic error. Its application results in selective application of ILC to those intervals where error signals of high level are concentrated and allows application of a single ILC acquisition to different setpoint trajectories. The adaptive filter finds particular use in lithographic scanning systems where it is used for varying scan length.
Owner:ASML NETHERLANDS BV
Method and apparatus for continuous measurement of motor symptoms in parkinson's disease and essential tremor with wearable sensors
Disclosed embodiments include an apparatus for generating a plurality of movement impairment indices from one or more kinematic signals to characterize movement disorders. Additionally we disclose methods for generating a plurality of movement impairment indices from one or more kinematic signals obtained from one or more kinematic sensors, said methods implemented in a digital computer with one or more processors in order to characterize movement disorders based on spectral analysis, regularity metrics, and time-frequency analsysis.
Owner:WEARABLES IP HLDG LLC +1
Wind turbine generator bearing fault diagnosis method for multi-channel deep convolutional neural network
ActiveCN107560849AImprove scalabilityAvoid subjectivityMachine bearings testingNeural architecturesExtensibilityVibration acceleration
The invention relates to a wind turbine generator bearing fault diagnosis method for a multi-channel deep convolutional neural network. The method comprises the steps of: simultaneously acquiring high-frequency vibration acceleration signals of a drive end and a non-drive end of a test bearing in various states by using a vibration acceleration sensor; analyzing the acquired vibration signals by using a time frequency analysis technology to obtain corresponding time frequency spectra; establishing a deep convolutional neural network diagnosis model, and training the diagnosis model by using the time frequency spectra and the states of the bearing as a training sample; evaluating the diagnosis model, and applying the diagnosis model to a bearing to be monitored. The method can realize automatic feature learning, avoids feature engineering, effectively utilizes multi-channel vibration signals, and has good universality and extensibility.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING)
Land mine detector
InactiveUS20050128125A1Minimizing functionDefence devicesDetection using electromagnetic wavesFeature setData set
Owner:UNIV OF FLORIDA RES FOUNDATION INC
Vehicle type classification method based on single frequency continuous-wave radar
InactiveCN101136141AThe overall structure is simple and reliableLow costWave based measurement systemsRoad vehicles traffic controlFrequency spectrumTime–frequency analysis
The vehicle classification method includes: the time-domain radar signal of single-frequency continuous wave radar is used as input to conduct time-frequency analysis to obtain a radar echo Doppler frequency spectrum chart changing along time; by Hafford counterchange the Doppler chart is mapped into a scattered central position parameter image; through characteristic picking-up, Karhunen-Loeve(K-L) screening and compressing, a characteristic sample is obtained, which is classified using Fisher rule to obtain the vehicle-type classification. For multi-type condition, multiple two-type classifiers are used to conduct respectively pairwise classification, according to the result of the classifiers said above the classification result is obtained by voting. Advantage: simple and reliable structure and low cost, conducting classification synchronously with detecting and speed-measuring of vehicles.
Owner:TSINGHUA UNIV
GIS mechanical oscillation signal time frequency analysis method based on VMD adaptive morphology
The invention discloses a GIS (Gas Insulated Switchgear) mechanical oscillation signal time frequency analysis method based on VMD (Variational Mode Decomposition) adaptive morphology. The GIS mechanical oscillation signal time frequency analysis method based on VMD adaptive morphology includes the steps: simulating different types of mechanical faults of GIS equipment; detecting oscillation signals of the GIS equipment in the normal condition and the simulation condition for many times; utilizing VMD to realize time frequency analysis of the oscillation signals, and finding out the change ofthe oscillation signal amplitude of the GIS device, following frequency distribution; and by integrating with Hilbert analysis, obtaining the characteristic criteria of the faults, by simulating different types of mechanical faults, establishing a GIS mechanical fault diagnosis database to realize time frequency analysis of the oscillation signals of the GIS equipment. The GIS mechanical oscillation signal time frequency analysis method based on VMD adaptive morphology performs time frequency analysis on the mechanical oscillation signals through the VMD algorithm, and can effectively processthe GIS oscillation signals so as to establish the GIS mechanical fault diagnosis database to provide theoretical basis for realizing field live detection of the GIS mechanical faults.
Owner:STATE GRID SHANDONG ELECTRIC POWER +1
Fracture monitoring using pressure-frequency analysis
ActiveUS7100688B2Electric/magnetic detection for well-loggingSurveyFrequency spectrumTime–frequency analysis
Changes occurring downhole during a fracturing process can create or reflect pressure signals. Capturing and evaluating such pressure waves during fracturing enables personnel to monitor, in real time or later, what happens downhole. When a fracture extends, a burst of acoustic noise is embodied in a pressure wave or signal, as is noise coming from other sources. By transforming time-based pressure signals to a frequency base, one can monitor this acoustic noise. In a particular implementation, a waterfall plot of frequency spectra at successive time slices of the original signal is used to determine frequency ridges, such as a ridge of decreasing frequencies indicates fracture extension and a ridge of increasing frequencies indicates either closure or proppant backing up in the fracture. Filtering, such as wavelet filtering, can be used. A fracturing process can be controlled in response to determining whether the fracture is extending.
Owner:HALLIBURTON ENERGY SERVICES INC
Digital camera and digital processing system for correcting motion blur using spatial frequency
ActiveUS7176962B2Improve efficiencyTelevision system detailsColor television detailsPhase differenceTime–frequency analysis
First image data and second image data are generated by capturing a subject image at a CCD. The first image data captured over a first exposure time manifest a relatively small extent of image blur. The second image data are captured over a second exposure time set longer than the first exposure time. A spatial frequency analysis is implemented on the first image data and the second image data to calculate the amplitude ratio and the phase difference of the high-frequency components in the two sets of image data. Based upon the amplitude ratio and the phase difference of the high-frequency components thus calculated, the spatial frequency component of the second image data is corrected to generate third image data in which any image blur has been corrected.
Owner:NIKON CORP
Time sequence analysis-based storm surge disaster early warning system
The invention discloses a time sequence analysis-based storm surge disaster early warning system, which comprises a database server, an early warning prediction model analysis module, an assistant decision making system, a Web server and a management user, wherein the database server stores historical monitoring data, real-time monitoring data, basic geographic information data, emergency plan data, related calculation model data and early warning data; the monitoring data and the early warning data are time sequence data; the early warning prediction model analysis module is mainly used for preprocessing the data, piecewise linearly expressing the time sequence data to fulfill dimension reduction and compression aims, performing similarity matching on the time sequence data and the historical monitoring data, and performing disaster early warning according to a similarity matching result; and the assistant decision making system displays assistant decision making information on the basis of geographical graphic information, and displays the assistant decision making information to a client of the management user through the deployed Web server.
Owner:SHANGHAI OCEAN UNIV
Method and system to convey the within-channel fine structure with a cochlear implant
The present invention provides a cochlear stimulation system and method for capturing and translating fine time structure (“FTS”) in incoming sounds and delivering this information spatially to the cochlea. The system comprises a FTS estimator / analyzer and a current navigator. An embodiment of the method comprises analyzing the incoming sounds within a time frequency band, extracting the slowly varying frequency components and estimating the FTS to obtain a more precise dominant FTS component within a frequency band. After adding the fine structure to the carrier to identify a precise dominant FTS component in each analysis frequency band (or stimulation channel), a stimulation current may be “steered” or directed, using the concept of virtual electrodes, to the precise spatial location (place) on the cochlea that corresponds to the dominant FTS component. This process is simultaneously repeated for each stimulation channel and each FTS component.
Owner:ADVANCED BIONICS AG
Distributed remote vibration monitoring and fault diagnosis system of large steam turbine-generator
InactiveCN102086784AQuick installation and layoutImprove accuracyMachines/enginesSafety/regulatory devicesSelf organizing map neural networkWeb service
The invention discloses a distributed remote vibration monitoring and fault diagnosis system of a large steam turbine-generator, comprising a database subsystem in which steam turbine-generator vibration data is stored, a workstation subsystem capable of providing real-time status monitoring, historical data analysis and fault symptom analysis, and a Web server subsystem provided with remote monitoring and fault diagnosing software, wherein, the subsystems are connected with one another by the Ethernet, and are integrated by a Web services technique. A method combining a traditional fault diagnosing technique based on Fourier analysis, a novel independent component analysis feature extraction technique, a Hilbert-yellow time frequency analysis technique, an empirical decomposition algorithm trend analysis technique and a self-organizing map neural network is adopted for monitoring and diagnosing in the system, thus improving the monitoring real time and the accuracy of diagnosis. The system has strong universality and reliability; and the system configuration can be adjusted, thus conveniently realizing distributed remote monitoring and diagnosis based on the internet as a medium.
Owner:ZHEJIANG UNIV
Online monitoring system and method for partial discharge of intelligent switch cabinet based on ultra-high frequency detection
InactiveCN102841296AIncreased frequency rangeSolve the problem of difficult to acquire high-frequency signalsTesting dielectric strengthTransmission systemsFrequency spectrumTransformer
The invention discloses an online monitoring system and a method for partial discharge of an intelligent switch cabinet based on ultra-high frequency detection. The online monitoring system comprises a sensor unit, a signal conditioning unit, a MCU (Micro Control Unit) unit, a communication unit, a system power supply and an upper machine monitoring unit. The online monitoring method comprises the following steps that: the sensor unit finishes collection of partial discharge signals in the switch cabinet; the signal conditioning unit realizes amplification, filtering, frequency reduction and bias of the signals, thus obtaining signals which can be converted by an ADC (Analog to Digital Converter) module in a DSP (Digital Signal Processor); the MCU unit realizes analysis and procession of the signals; and data are uploaded to an upper machine in a monitoring room through an Ethernet. According to the online monitoring system and the method for the partial discharge of the intelligent switch cabinet based on the ultra-high frequency detection disclosed by the invention, collection and procession of high-frequency signals conducted by the DSP are realized by adopting a frequency spectrum shifting technology; a time-frequency analysis technology and a mode identification theory are applied to the monitoring system, therefore, the monitoring system is functional in fault diagnosis; and in addition, an IEC61850 standard is adopted by the system, consequently, management of various IEDs (Intelligent Electronic Devices) and interconnecting as well as networking of equipment in a transformer substation are convenient.
Owner:JIANGSU UNIV OF SCI & TECH
Transformer vibration signal de-noising method based on EEMD kurtosis threshold value
InactiveCN103902844AImprove performanceSubsonic/sonic/ultrasonic wave measurementSpecial data processing applicationsTime domainTransformer
The invention discloses a transformer vibration signal de-noising method based on an EEMD kurtosis threshold value. Many methods have been put forward by domestic and foreign scholars for de-noising of non-stationary signals and are roughly divided into three major types of time-frequency analysis methods based on time domain statistics, Fourier transform and wavelet transform. All the methods have respective advantages and disadvantages, for instance, the theory of the frequency domain method is mature, but signals with overlapped frequency are difficult to separate; although the wavelet transform method has the multi-resolution performance, the de-noising effect of the method usually depends on selection of a wavelet base and a threshold value. The method includes the steps that first, random signals are subjected to EEMD, then, each intrinsic mode function is subjected to autocorrelation function calculation, the kurtosis coefficient of each IMF is solved, next, the IMFs are differentiated through the threshold value, and therefore noisy signals can be removed. The method is used for de-noising of transformer vibration signals.
Owner:STATE GRID CORP OF CHINA +2
Method of processing of compressed image into a gamut mapped image using spatial frequency analysis
ActiveUS20090285478A1Minimize changesExtensive resourcesImage enhancementColor signal processing circuitsPattern recognitionGamut
The spatial frequency analysis contained in the compressed image is used not only for decompression of images but also for the selection of an appropriate gamut mapping algorithm. Computation resources are then saved because no specific spatial frequency analysis is required for the selection of an appropriate gamut mapping algorithm.
Owner:INTERDIGITAL MADISON PATENT HLDG
Monitoring method based on image features and LLTSA algorithm for tool wear state
ActiveCN107378641ARealization of wear status monitoringFully automatedMeasurement/indication equipmentsTime–frequency analysisTool wear
The invention relates to a monitoring method based on image features and an LLTSA algorithm for a tool wear state. According to the method, an image texture feature extraction technology is introduced into the field of tool wear fault diagnosis, and monitoring for the tool wear state is realized in combination with three flows of ' signal denoising', 'feature extraction and optimization' and 'mode recognition'. The method comprises the steps of firstly, acquiring an acoustic emission signal in a tool cutting process through an acoustic emission sensor, and carrying out signal denoising processing through an EEMD diagnosis; secondly, carrying out time-frequency analysis on a denoising signal through S transformation, converting a time-frequency image to a contour gray-level map, extracting image texture features through a gray-level co-occurrence matrix diagnosis, and then further carrying out dimensionality reduction and optimization on an extracted feature vector through a scatter matrix and the LLTSA algorithm to obtain a fusion feature vector; and finally training a discrete hidden Markov model of the tool wear state through the fusion feature vector, and establishing a classifier, thereby realizing automatic monitoring and recognition for the tool wear state.
Owner:NORTHEAST DIANLI UNIVERSITY
Detecting illuminant flicker
InactiveUS20100045819A1Improve abilitiesImprove dynamic rangeTelevision system detailsColor signal processing circuitsComputer graphics (images)Time–frequency analysis
A method of determining when an image capture device with a rolling shutter is in an environment having a flickering illuminant by using autocorrelation or frequency analysis of difference vectors produced from first and second captured images.
Owner:INTELLECTUAL VENTURES FUND 83 LLC
System and method for constrained least-squares spectral processing and analysis of seismic data
ActiveUS20140067273A1Reduced window smearingFavorable for determinationSeismic signal processingSpecial data processing applicationsTime–frequency analysisShort time fourier transformation
An inversion-based algorithm for computing the time frequency analysis of reflection seismograms using constrained least-squares spectral analysis is formulated and applied to modeled seismic waveforms and real seismic data. The Fourier series coefficients are computed as a function of time directly by inverting a basis of truncated sinusoidal kernels for a moving time window. Spectra may be provided that have reduced window smearing for a given window length relative to the discrete Fourier transform irrespective of window shape, and a time-frequency analysis with a combination of time and frequency resolution that is superior to the short time Fourier transform and the continuous wavelet transform. The reduction in spectral smoothing enables enhanced determination of spectral characteristics of interfering reflections within a short window. The degree of resolution improvement relative to the short time Fourier transform increases as window length decreases.
Owner:LUMINA GEOPHYSICAL
System for pre-testing and diagnosing electro magnetic interference of electronic equipment and method thereof
ActiveCN101701986AStrong complementarityGood synergySpectral/fourier analysisElectromagentic field characteristicsEnvironmental noiseFrequency spectrum
The invention discloses a system for pre-testing and diagnosing the electro magnetic interference of electronic equipment, which is characterized by comprising a data collecting module, an interference source diagnosing and locating module, an environmental noise eliminating module and a visual time-frequency analyzer, wherein the data collecting module, the interference source diagnosing and locating module and the environmental noise eliminating module are respectively connected with the visual time-frequency analyzer, and the visual time-frequency analyzer achieves the drive of the data collecting module, the call of the interference source diagnosing and locating module and the environmental noise eliminating module and the monitoring and displaying of time-domain waveforms and frequency spectrums. The invention also discloses a method for pre-testing and diagnosing the electro magnetic interference of electronic equipment, which utilizes a LabView visual instrument platform and Matlab programming environmental developing software to pre-test and diagnose signals. The invention can pre-test and diagnose the electro magnetic interference of electronic equipment at common test fields, and has high automation and carrying degree and simple usage and reduces cost.
Owner:CHINA SHIP DEV & DESIGN CENT
De-noising method of transient electromagnetic detecting echo signal
InactiveCN101882964AOptimistic about noise reductionFix extraction issuesTransmission noise suppressionDecompositionTime–frequency analysis
The invention provides a de-noising method of a transient electromagnetic detecting receiving signal, which comprises the following steps of: decomposing a transient electromagnetic detecting receiving signal by means of empirical mode, i.e. 'screening'; leading all extreme points of signal data x (t) to form into an upper envelope and a lower envelope through a cubic spline interpolation function; obtaining a mean value m1, wherein a first component h1=x (t)-m1, and the h1 is regarded as data to be processed to repeat the screening with k times; obtaining a first IMF when the standard deviation SD of the continues twice screening results meets the requirement, wherein c1=h1k=h1(k-1)-m1k and a residual signal r1; repeatedly 'screening' the r1; decomposing signal data to be n IMFs and one residual quantity rn; judging signal dominant and noise dominant component according to the diminishing condition of each IMF energy; and accumulating again after filtering each IMF of the signal dominant to obtain the de-noised signal. The method adopts empirical mode decomposition of adaptive time-frequency analysis, does not need priori information, respectively processes the different natural frequencies of the signal, removes high-frequency noise, filters high-frequency noise, is applied to removing the noise of the non-linear and non-stationary transient electromagnetic detecting echo signal, and is patricianly applied to removing the noise of a deep echo signal.
Owner:百色美联天衡地质探测雷达制造有限责任公司
Radar level gauge system
ActiveUS7284425B2Reliable conclusionWave based measurement systemsMachines/enginesPropagation timeRadar
Owner:ROSEMOUNT TANK RADAR
Portable partial discharge detecting and diagnosing device
ActiveCN104749498ASolve the errorImprove data processing and analysis performanceTesting dielectric strengthTransformerTime–frequency analysis
The invention discloses a portable partial discharge detecting and diagnosing device. The device comprises a partial discharge detector, a cable, a pre-sensor and a charger device, wherein the partial discharge detector comprises a lower computer and an upper computer; the lower computer comprises a simulation unit module, an FPGA module, an ARM module, a clock and reset module and a power management module; the upper computer is a Linux industrial personal computer. The portable partial discharge detecting and diagnosing device is provided with a 14-bit 100MHz two-channel acquisition system having the maximum storage depth of 64Mbit; the display of the characteristic spectrum of defects and the model identification of faults can be completed accurately in such a manner of PRPD clustering analysis in combination with impulse waveform time-frequency analysis; meanwhile, a radio-frequency sensor and an ultrahigh-frequency sensor are simultaneously provided, and the pulse current detection and the ultrahigh-frequency detection on primary equipment can be completed by replacing the pre-filter; the device is small in volume, light in weight, and capable of supplying power to a battery and convenient for field live testing and polling of a transformer.
Owner:XI AN JIAOTONG UNIV
Ion trap mass spectrometer
ActiveCN102884608AImprove acquisitionPerfectly compatibleStability-of-path spectrometersTime-of-flight spectrometersTime–frequency analysisMass analyzer
The application relates to an ion trap mass spectrometer. An apparatus 41 and operation method are provided for an electrostatic trap mass spectrometer with measuring frequency of multiple isochronous ionic oscillations. For improving throughput and space charge capacity, the trap is substantially extended in one Z-direction forming a reproduced two-dimensional field. Multiple geometries are provided for trap Z-extension. The throughput of the analysis is improved by multiplexing electrostatic traps. The frequency analysis is accelerated by the shortening of ion packets and either by Wavelet-fit analysis of the image current signal or by using a time- of-flight detector for sampling a small portion of ions per oscillation. Multiple pulsed converters are suggested for optimal ion injection into electrostatic traps.
Owner:LECO CORPORATION
Adaptive radiation source modulation identification method based on time-frequency analysis
ActiveCN107301432AAvoid missing low signal-to-noise ratio signal featuresAvoid situations where high signal-to-noise ratio signal features are redundantCharacter and pattern recognitionComputation complexityTime–frequency analysis
The invention provides an adaptive radiation source modulation identification method based on time-frequency analysis. The method comprises the steps of I, carrying out time-frequency analysis on a received radiation source signal by use of time frequency distribution, converting the radiation signal from a time-domain signal to a time-frequency two-dimensional image; II, reducing computation complexity and characteristic dimension by use of an image processing technology, and improving the proportion of signal characteristic information in the image through normalization, binaryzation, image thinning and image preprocessing operations; III, carrying out image shape characteristic extraction on the preprocessed image in combination with a second-order and four-order moment estimation method by use of an adaptive principal component analysis algorithm; and IV, identifying a modulation mode of the radiation source signal by use of an LIBSVM (Library for Support Vector Machine) classifier. According to the adaptive radiation source modulation identification method based on time-frequency analysis, the characteristic missing of a low signal to noise ratio signal can be effectively avoided, and characteristic redundancy of a high low signal to noise ratio can be also avoided, and the modulation identification rate is not affected at the same time.
Owner:HARBIN ENG UNIV
Online detection method for torsion vibration signal of automotive power transmission system
InactiveCN101871846AAccurate torsional vibration frequencyAccurate calculation of torsional vibration frequencyVibration measurement in solidsVehicle testingElectric power transmissionVibration control
Owner:TSINGHUA UNIV
Method of Real Time-Estimation of Indicators of the Combustion State of an Internal-Combustion Engine
InactiveUS20080051975A1Analogue computers for vehiclesInternal-combustion engine testingCombustionEstimation methods
A method of real-time estimation of indicators of the engine combustion state from signals containing oscillating components. A signal, such as a vibration signal for example, correlated with the engine combustion, is acquired as a function of time or of the crank angle. Real-time filtering and time-frequency analysis of this signal is carried out and indicators of the combustion state are estimated in real time from this analysis. The method has application for combustion control of an internal-combustion engine.
Owner:INST FR DU PETROLE
Method based on improved HHT algorithm and applied to time-frequency analysis of GIS (Gas Insulated Switchgear) mechanical vibration signals
InactiveCN106840637AThe result is accurateEasy to handleMachine part testingDecompositionTime–frequency analysis
The invention discloses a method based on an improved HHT algorithm and applied to time-frequency analysis of GIS (Gas Insulated Switchgear) mechanical vibration signals. The method comprises the following steps: measuring GIS normal operation vibration signals and GIS vibration signals under faults, extracting characteristic quantities of the vibration signals by using ensemble empirical mode decomposition (EEMD), and carrying out hilbert transformation (HT) on the signals obtained by EEMD preprocessing to carry out time-frequency analysis on the GIS mechanical vibration signals. Through the method, the GIS vibration signals can be effectively processed by carrying out time-frequency analysis of the GIS mechanical vibration signals through adoption of a method of carrying out HT after preprocessing via an EEMD algorithm, so that a GIS mechanical fault diagnosis database is established; the theoretical basis is provided for achieving on-site live detection of the GIS mechanical faults.
Owner:STATE GRID SHANDONG ELECTRIC POWER +1
Hyperspectral remote sensing image band selection method based on time sequence important point analysis
InactiveCN101859383AReduce computational complexityThe realization process is convenientImage analysisCharacter and pattern recognitionSequence analysisComputation complexity
The invention discloses a hyperspectral remote sensing image band selection method based on time sequence important point analysis, which realizes the selection of characteristic bands by clustering the data sample of a hyperspectral remote sensing image into K categories by a K-means clustering method based on DBI (Data Base Index), using wavelet analysis to carry out noise-removal processing and then extracting important points according to the time sequence analysis. Compared with the prior art, the method has the advantages of low computation complexity and convenient and rapid realization process and provides a brand-new idea for reducing dimensions of high-dimension data.
Owner:HOHAI UNIV
Micro moving target feature extracting method based on micro Doppler effect
The invention provides a micro moving target feature extracting method based on micro Doppler effect, which comprises the steps that HHT (Hilbert-Huang transform) is introduced into micro moving target feature extracting, an HHT algorithm based on the down sampling EMD (empirical mode decomposition) is provided by aiming at the problem of the modal mixing of the feature extracting of the HHT, and procedures of resolving, summing and averaging on the noisy EMD are performed by the multiple groups of data obtained by performing the down sampling on original signals, thus effectively solving the mixing problem of spectrogram modes in the vibration target feature extracting of the HHT, inhibiting the noise of the original signals, improving the signal to noise ratio, reducing the EMD operating complexity of the multiple groups of data, greatly reducing the operating amount, improving the operating speed and achieving a better micro Doppler feature extracting effect. The micro Doppler feature extracting model based on the improved HHT is provided by integrating the advantages of the traditional time frequency analysis method and the improved HHT algorithm, a spectrogram peak value estimation method is added into the model, the resolution in the traditional time frequency spectrogram is improved to be used as an assisting method for the HHT feature extracting, and the requirements on accuracy and practicability of the extracted vibration target feature are achieved.
Owner:SICHUAN UNIV
Non-contact heart rate measurement method and device based on Euler image magnification
ActiveCN107529646ARealize automatic measurementImage analysisCharacter and pattern recognitionTime domainHeart rate measurement
The embodiment of the invention discloses a non-contact heart rate measurement method and a device based on Euler image magnification, used for solving the technical problems existing in the existingnon-contact heart rate measurement method that the heart rate is great in same-frequency noise interference and is greatly influenced by an environment temperature, isolation signal authenticity lacksjudgment and the like. The non-contact heart rate measurement method and device based on Euler image magnification in the embodiment of the invention comprises the following steps: S1, magnifying tiny change of radial artery jump in a video through an Euler image magnification technology; S2, performing luminance variance statistics on a video frame pixel point luminance channel after magnifyingthe tiny change of radial artery jump in a time domain, performing skin segmentation on the video frame subjected to magnification of the tiny change of radial artery jump, and extracting a radial artery jump area; and S3, performing time-frequency analysis on the radial artery jump area so as to calculate the heart rate.
Owner:GUANGDONG UNIV OF TECH
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